7,086 research outputs found
Sustainability of organic and conventional beef cattle farms in SW Spanish rangelands (‘dehesas’): a comparative study
Organic production in Spain has increased substantially in recent years due to several factors, such as the growing interest of the European Union towards preserving sensitive ecosystems; the potential role of organic production in the socio-economic development of rural areas and the growing consumers' demand for safer and higher quality foods. Within this framework, this paper analyzes the beef sector of SW Spanish rangelands (dehesas). These are traditional systems characteristic of the Iberian Peninsula where native herbaceous vegetation and evergreen species of Quercus provide the basis for extensive beef farms. Alt-hough traditional management in dehesa farms is of vital importance for the sustainability of this particular ecosystem, in the last years many farms have turned to organic production, trying to take advantage both of new subsidies and of new market trends.With this study, we try to evalu-ate the sustainability of conventional and organic beef production systems in dehesas in Extre-madura (SW Spain), trying to determine the level these systems are contributing both to the preservation of this sensitive ecosystem and to the socioeconomic development of the region. To this end, we apply a methodological adaptation of the MESMIS methodology to 90 dehesa beef farms located in Extremadura (SW Spain). MESMIS is based on the evaluation of basic attributes of sustainability that allow one to make a simultaneous and comparative analysis of different types of farms. It has been found that organic farms are the most sustainable, obtaining higher scores than con-ventional farms in stability and self-reliance, and similar scores in productivity, adaptability, and equity. Organic dehesa beef farms show little dependence on external products and services and are more adapted to their environment (lower stocking rates for an optimal use of the system's feedstuff production), those being the clues for their enhanced sustainability
Conversión de sistemas de producción caprinos de áreas desfavorecidas a ganadería ecológica
INTRODUCTION: The Spanish goat sector's crisis has led to the abandonment of a large number of farms. At present, sector's expectations are reduced, which threatens farms' permanence. This in turn means a loss of agricultural biodiversity, reduced economic activity and loss of rural population. In this context, it is necessary to implement strategies to ensure farms' continuity . In this sense, the conversion to the organic model is proposed in the farms analyzed.
METHODOLOGY: To study the possibility and feasibility of such conversion an analysis of their structure (technical and economic characteristics), an assessment of farms' sustainability (based on social, economic and environmental parameters) has been carried out. For this purpose, the MESMIS Framework was used
Evaluación de la sostenibilidad de explotaciones caprinas extremeñas en áreas desfavorecidas como herramienta de apoyo en la conversión hacia explotaciones ecológicas.
INTRODUCTION: The Ibores-Villuercas region (located in SW Spain) is known for its dairy goat farms producing cheeses of high quality (P.D.O. Queso Ibores).
The present study characterizes such farms and assess their sustainability, as a tool to determine which farms present more feasibility to carry out a conversion to the organic system. This conversion could be used as a marketing tool for these farms, and contribute to local development (both economically and socially), ensuring the maintenance of the farms and rural population while enabling the preservation of valuable landscapes.
METHODOLOGY: farms where classified using cluster analysis. Later, a sustainability assessment of the clusters (groups of farms) was carried out. Finally, farms' difficulties and advantages producing under the organic model where predicted.
RESULTS and DISCUSSION: 3 groups of farms were obtained. Group 1 farms were intensive ones, using highly-productive dairy breeds fed high proportion of concentrates. Group 2 were semi-extensive of higher surface and mixed with sheeps, where autochthonous and allochthonous races are reared, and management is closer to a traditional one. Finally, group 3 was a traditional one, closer to the orgnaic management, with low stocking rates and native breeds feeding local feed resources.
Regarding the attributes of sustainability, group 3 showed advantages in terms of self-management, which is important under the organic system and areas of scarcity of feed resources (such as that studied)
Comparative Sustainability Assessment of Extensive Beef Cattle Farms
This chapter analyzes the sustainability of beef cattle systems of the Spanish Rangelands known as “Dehesas”. These are traditional systems of the Iberian Peninsula where native herbaceous vegetation and evergreen species of Quercus provide the basis for extensive livestock farms. These systems are considered as outstanding High Nature Value (HNV) farming systems and the most extensive agroforestry systems in Europe according to CORINE Land Cover.
Beef farms in this area show low stocking rates and a small dependence on foodstuff purchases.However, certain changes have occurred in the last decadesdue to the Common Agricultural Policy (CAP). On the one hand, some farms have become more intensified, as a way to maximize the revenues from the CAP subsidies. On the other hand, many farms have turned to organic production, trying to take advantage both of new subsidies and of new market trends.
In this regard, the organic livestock farming model is gaining weight as an option for sustainable production since, according to various authors, these systems have advantages over conventional and intensive systems. In fact, organic production in the area has increased substantially in recent years due to several factors, such as the growing interest of the EU towards preserving sensitive ecosystems, the potential role of organic production in the development of rural areas and the growing consumers’ demand for safer and higher quality foods produced under ethical and environmental standards.
In this study, we carried out a comparative assessment of the sustainability of different conventional and organic beef production systems located in dehesa rangelands. The systems analyzed were classified as follows. (i) non-organic farms (Conventional); (ii) organic farms that sold calves at weaning age as conventional ones (Organic 1); (iii) organic farms that fattened and sold their calves as organic (Organic 2). An adaptation of the MESMIS multicriteria framework was applied to calculate sustainability indices for each system. The results showed that the Organic 2 farms scored highest on most of the attributes of sustainability, as well as on the environmental and economic dimensions of sustainability. Thus, they were the most sustainable system (66.55%), followed by the Organic 1 (61.04%) and Conventional ones (56.89%). Despite Organic 2 was the most sustainable system, its implementation is complex due to both the high costs of organic inputs and the weak demand for organic beef.
The results also showed that all three types of systems need to improve in certain aspects that are crucial in the current and future context of the livestock sector. These aspects are: reducing the dependence on external feed, implementing more environmentally friendly farming practices, and farm diversification
Piezoresistor sensor fabrication by direct laser writing on hydrogenated amorphous silicon
In this paper we report on the 532 nm Nd:YAG laser-induced crystallization of 10 nm thick boron-doped hydrogenated amorphous silicon thin films deposited on flexible polyimide and on rigid oxidized silicon wafers by hot-wire chemical vapor deposition. The dark conductivity increased from ~10-7 -1cm-1, in the as-deposited films, to ~10 and 50 -1cm-1 after laser irradiation, on rigid and flexible substrates, respectively. Depending on type of substrate, laser power and fluence, a Raman crystalline fraction between 55 and 90% was measured in HWCVD films, which was higher than observed in rf-PECVD films (35 - 55%). Crystallite size remained small in all cases, in the range 6-8 nm. Due to a very high conductivity contrast (>7 orders of magnitude) between amorphous and crystallized regions, it was possible to define conductive paths in the a-Si:H matrix, by mounting the sample on a X-Y software-controlled movable stage under the laser beam, with no need for the usual lithography steps. The resistors scribed by direct laser writing had piezoresistive properties, with positive gauge factor ~1. The details of the laser interaction process with the Si film were revealed by scanning electron microscopy imaging.(undefined
Evolving neural networks to optimize material usage in blow molded containers
In industry, there is a growing interest to optimize the use of raw material in blow molded products. Commonly, the material in blow molded containers is optimized by dividing the container into different sections and minimizing the wall thickness of each section. The definition of discrete sections is limited by the shape of the container and can lead to suboptimal solutions. This study suggests determining the optimal thickness distribution for blow molded containers as a function of geometry. The proposed methodology relies on the use of neural networks and finite element analysis. Neural networks are stochastically evolved considering multiple objectives related to the optimization of material usage, such as cost and quality. Numerical simulations based on finite element analysis are used to evaluate the performance of the container with a thickness profile determined by feeding the coordinates of mesh elements in finite element model into the neural network. The proposed methodology was applied to the design of industrial bottle. The obtained results suggested the validity and usefulness of this methodology by revealing its ability to identify the most critical regions for the application of material.FCT -Fundação para a Ciência e a Tecnologia(PEst-E/EEI/UI0319/2014)info:eu-repo/semantics/publishedVersio
Principales factores económicos y de estructura en explotaciones de vacuno ecológico en dehesas de Badajoz
publishedTomo I . Sección: Sistemas Ganaderos-Economía y Gestión. Sesión: Economía I. Ponencia nº 1
Hydrogel 3D in vitro tumor models for screening cell aggregation mediated drug response
Hydrogel-based 3D in vitro models comprising tumor ECM-mimetic biomaterials exhibit superlative potential as preclinical testing platforms for drug discovery and bioperformance screening. However, during hydrogel design and testing stages, the ideal selection between cancer cell laden 3D models or spheroid embedded hydrogel platforms remains to be elucidated. Selecting a disease-mimicking cellular arrangement within ECM hydrogels is paramount for anti-cancer therapeutics performance evaluation and may lead to differential outcomes. To investigate the effects assigned to varying cellular-arrangement, we developed dense 3D spheroid microtumors and cell-laden MG-63 osteosarcoma platforms embedded in GelMA and Matrigel ECM-mimetic scaffolds. These platforms enabled cancer cells/3D microtissues maturation and lorlatinib drug performance screening. Initial 3D spheroids assembly via the liquid overlay technique, resulted in the fabrication of dense cellular aggregates with reproducible size, morphology and necrotic core formation, thus mimicking the native tumor. Upon in vitro maturation, MG-63 spheroids encapsulated in hydrogel scaffolds exhibited significantly higher invasion and drug resistance than their cell laden hydrogel counterparts. Such data reveals inherent physiological and drug response variances among randomly distributed osteosarcoma cells and 3D spheroid-laden hydrogels. Overall, this highlights the importance of evaluating different cellular aggregation states when designing ECM-mimetic hydrogels for in vitro tumor modeling and high-throughput screening of anti-cancer therapeutics.publishe
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