10 resultados para natural-resource-based view

em Universidad Politécnica de Madrid


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The author participated in the 6 th EU Framework Project ―Q-pork Chains (FP6-036245-2)‖ from 2007 to 2009. With understanding of work reports from China and other countries, it is found that compared with other countries, China has great problems in pork quality and safety. By comparing the pork chain management between China and Spain, It is found that the difference in governance structure is one of the main differences in pork chain management between Spain and China. In China, spot-market relationship still dominates governance structure of pork chain, especially between the numerous house-hold pig holders and the great number of small slaughters. While in Spain, chain agents commonly apply cooperatives or integrations to cooperate. It also has been proven by recent studies, that in quality management at the chain level that supply chain integration has a direct effect on quality management practices (Han, 2010). Therefore, the author started to investigate the governance structure choices in supply chain management. And it has been set as the first research objective, which is to explain the governance structure choices process and the influencing factors in supply chain management, analyzing the pork chains cases in Spain and in China. During the further investigation, the author noticed the international trade of pork between Spain and China is not smooth since the signature of bi-lateral agreement on pork trade in 2007. Thus, another objective of the research is to find and solve the problems exist in the international pork chain between Spain and China. For the first objective, to explain the governance structure choices in supply chain management, the thesis conducts research in three main sections. 10 First of all, the thesis gives a literature overview in chapter two on Supply Chain Management (SCM), agri-food chain management and pork chain management. It concludes that SCM is a systems approach to view the supply chains as a whole, and to manage the total flow of goods inventory from the supplier to the ultimate customer. It includes the bi-directional flow of products (materials and services) and information, and the associated managerial and operational activities. And it also is a customer focus to create unique and individual source of customer value with an appropriate use of resources, leading to customer satisfaction and building competitive chain advantages. Agri-food chain management and pork chain management are applications of SCM in agri-food sector and pork sector respectively. Then, the research gives a comparative study in chapter three in the pork chain and pork chain management between Spain and China. Many differences are found, while the main difference is governance structure in pork chain management. Furthermore, the author gives an empirical study on governance structure choice in chapter five. It is concluded that governance structure of supply chain consists of a collection of rules/institutions/constraints structuring the transactions between the various stakeholders. Based on the overview on literatures closely related with governance structure, such as transaction cost economics, transaction value analysis and resource-based view theories, seven hypotheses are proposed, which are: Hypothesis 1: Transaction cost has positive relationship with governance structure choice Hypothesis 2: Uncertainty has positive relationship with transaction cost; higher uncertainty exerts high transaction cost Hypothesis 3: The relationship between asset specificity and transaction cost is positive Hypothesis 4: Collaboration advantages and governance structure choice have positive relationship11 Hypothesis 5: Willingness to collaborate has positive relationship with collaboration advantages Hypothesis 6: Capability to collaborate has positive relationship with collaboration advantages Hypothesis 7: Uncertainty has negative effect on collaboration advantages It is noted that as transaction cost value is negative, the transaction cost mentioned in the hypotheses is its absolute value. To test the seven hypotheses, Structural Equation Model (SEM) is applied and data collected from 350 pork slaughtering and processing companies in Jiangsu, Shandong and Henan Provinces in China is used. Based on the empirical SEM model and its results, the seven hypotheses are proved. The author generates several conclusions accordingly. It is found that the governance structure choice of the chain not only depends on transaction cost, it also depends on collaboration advantages. Exchange partners establish more stable and more intense relationship to reduce transaction cost and to maximize collaboration advantages. ―Collaboration advantages‖ in this thesis is defined as the joint value achieved through transaction (mutual activities) of agents in supply chains. This value forms as improvements, mainly in mutual logistics systems, cash response, information exchange, technological improvements and innovative improvements and quality management improvements, etc. Governance structure choice is jointly decided by transaction cost and collaboration advantages. Chain agents take different governance structures to coordinate in order to decrease their transaction cost and to increase their collaboration advantages. In China´s pork chain case, spot market relationship dominates the governance structure among the numerous backyard pig farmer and small family slaughterhouse 12 as they are connected by acquaintance relationship and the transaction cost in turn is low. Their relationship is reliable as they know each other in the neighborhood; as a result, spot market relationship is suitable for their exchange. However, the transaction between large-scale slaughtering and processing industries and small-scale pig producers is becoming difficult. The information hold back behavior and hold-up behavior of small-scale pig producers increase transaction cost between them and large-scale slaughtering and processing industries. Thus, through the more intense and stable relationship between processing industries and pig producers, processing industries reduce the transaction cost and improve the collaboration advantages with their chain partners, in which quality and safety collaboration advantages be increased, meaning that processing industries are able to provide consumers products with better quality and higher safety. It is also drawn that transaction cost is influenced mainly by uncertainty and asset specificity, which is in line with new institutional economics theories developed by Williamson O. E. In China´s pork chain case, behavioral uncertainty is created by the hold-up behaviors of great numbers of small pig producers, while big slaughtering and processing industries having strong asset specificity. On the other hand, ―collaboration advantages‖ is influenced by chain agents´ willingness to collaborate and chain agents´ capabilities to cooperate. With the fast growth of big scale slaughtering and processing industries, they are more willing to know and make effort to cooperate with their chain members, and they are more capable to create joint value together with other chain agents. Therefore, they are now the main chain agents who drive more intense and stable governance structure in China‘s pork chain. For the other objective, to find and solve the problems in the international pork chain between Spain and China, the research gives an analysis in chapter four on the 13 international pork chain. This study gives explanations why the international trade of pork between Spain and China is not sufficient from the chain perspective. It is found that the first obstacle is the high quality and safety requirement set by Chinese government. It makes the Spanish companies difficult to get authorities to export. Other aspects, such as Spanish pork is not competitive in price compared with other countries such as Denmark, United States, Canada, etc., Chinese consumers do not have sufficient information on Spanish pork products, are also important reasons that Spain does not export great quantity of pork products to China. It is concluded that China´s government has too much concern on the quality and safety requirements to Spanish pork products, which makes trade difficult to complete. The two countries need to establish a more stable and intense trade relationship. They also should make the information exchange sufficient and efficient and try to break trade barriers. Spanish companies should consider proper price strategies to win the Chinese pork market

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Vivimos una época en la que el mundo se transforma aceleradamente. La globalización está siguiendo un curso imparable, la población mundial así como la población urbana siguen creciendo, y en los países emergentes los ingresos promedios aumentan, resultando en un cambio también acelerado de las dietas y hábitos alimentarios. En conjunto esos factores están causando un aumento fundamental de la demanda de alimentos. Junto con la apertura de los mercados agrícolas, estos procesos han provocado un crecimiento del comercio internacional de alimentos durante la última década. Dado que muchos países de América Latina están dotados de abundancia de recursos naturales, estas tendencias han producido un crecimiento rápido de las exportaciones de bienes primarios desde América Latina al resto del mundo. En sólo 30 años la participación en el mercado agrícola de América Latina casi se ha duplicado, desde 10% en 1980 a 18% en 2010. Este aumento del comercio agrícola ha dado lugar a un debate sobre una serie de cuestiones cruciales relacionadas con los impactos del comercio en la seguridad alimentaria mundial, en el medio ambiente o en la reducción de la pobreza rural en países en desarrollo. Esta tesis aplica un marco integrado para analizar varios impactos relacionados con la transformación de los mercados agrícolas y los mercados rurales debidos a la globalización y, en particular, al progresivo aumento del comercio internacional. En concreto, la tesis aborda los siguientes temas: En primer lugar, la producción mundial de alimentos tendrá que aumentar considerablemente para poder satisfacer la demanda de una población mundial de 9000 millones personas en 2050, lo cual plantea grandes desafíos sobre los sistemas de la producción de alimentos. Alcanzar este logro, sin comprometer la integridad del medio ambiente en regiones exportadoras, es un reto aún mayor. En este contexto, la tesis analiza los efectos de la liberalización del comercio mundial, considerando distintas tecnologías de producción agraria, sobre unos indicadores de seguridad alimentaria en diferentes regiones del mundo y sobre distintos indicadores ambientales, teniendo en cuenta escalas diferentes en América Latina y el Caribe. La tesis utiliza el modelo “International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT)” – un modelo dinámico de equilibrio parcial del sector agrícola a escala global – para modelar la apertura de los mercados agrícolas así como diferentes escenarios de la producción hasta el año 2050. Los resultados del modelo están vinculados a modelos biofísicos para poder evaluar los cambios en la huella hídrica y la calidad del agua, así como para cuantificar los impactos del cambio en el uso del suelo sobre la biodiversidad y los stocks de carbono en 2050. Los resultados indican que la apertura de los mercados agrícolas es muy importante para mejorar la seguridad alimentaria a nivel mundial, sin embargo, produce también presiones ambientales indeseables en algunas regiones de América Latina. Contrastando dos escenarios que consideran distintas modos de producción, la expansión de la tierra agrícola frente a un escenario de la producción más intensiva, se demuestra que las mejoras de productividad son generalmente superiores a la expansión de las tierras agrícolas, desde un punto de vista económico e ambiental. En cambio, los escenarios de intensificación sostenible no sólo hacen posible una mayor producción de alimentos, sino que también generan menos impactos medioambientales que los otros escenarios futuros en todas sus dimensiones: biodiversidad, carbono, emisiones de nitratos y uso del agua. El análisis muestra que hay un “trade-off” entre el objetivo de alcanzar la sostenibilidad ambiental y el objetivo de la seguridad alimentaria, independiente del manejo agrícola en el futuro. En segundo lugar, a la luz de la reciente crisis de los precios de alimentos en los años 2007/08, la tesis analiza los impactos de la apertura de los mercados agrícolas en la transmisión de precios de los alimentos en seis países de América Latina: Argentina, Brasil, Chile, Colombia, México y el Perú. Para identificar las posibles relaciones de cointegración entre los índices de precios al consumidor de alimentos y los índices de precios de agrarios internacionales, sujetos a diferentes grados de apertura de mercados agrícolas en los seis países de América Latina, se utiliza un modelo simple de corrección de error (single equation error correction). Los resultados indican que la integración global de los mercados agrícolas ha dado lugar a diferentes tasas de transmisión de precios en los países investigados. Sobre todo en el corto plazo, las tasas de transmisión dependen del grado de apertura comercial, mientras que en el largo plazo las tasas de transmisión son elevadas, pero en gran medida independientes del régimen de comercio. Por lo tanto, durante un período de shocks de precios mundiales una mayor apertura del comercio trae consigo más inestabilidad de los precios domésticos a corto plazo y la resultante persistencia en el largo plazo. Sin embargo, estos resultados no verifican necesariamente la utilidad de las políticas comerciales, aplicadas frecuentemente por los gobiernos para amortiguar los shocks de precios. Primero, porque existe un riesgo considerable de volatilidad de los precios debido a cambios bruscos de la oferta nacional si se promueve la autosuficiencia en el país; y segundo, la política de proteccionismo asume el riesgo de excluir el país de participar en las cadenas de suministro de alto valor del sector agrícola, y por lo tanto esa política podría obstaculizar el desarrollo económico. Sin embargo, es indispensable establecer políticas efectivas para reducir la vulnerabilidad de los hogares a los aumentos repentinos de precios de alimentos, lo cual requiere una planificación gubernamental precisa con el presupuesto requerido disponible. En tercer lugar, la globalización afecta a la estructura de una economía y, por medios distintos, la distribución de los ingreso en un país. Perú sirve como ejemplo para investigar más profundamente las cuestiones relacionadas con los cambios en la distribución de los ingresos en zonas rurales. Perú, que es un país que está cada vez más integrado en los mercados mundiales, consiguió importantes descensos en la pobreza extrema en sus zonas rurales, pero a la vez adolece de alta incidencia de pobreza moderada y de desigualdad de los ingresos en zonas rural al menos durante el periodo comprendido entre 2004 y 2012. Esta parte de la tesis tiene como objetivo identificar las fuerzas impulsoras detrás de estas dinámicas en el Perú mediante el uso de un modelo de microsimulación basado en modelos de generación de ingresos aplicado a nivel los hogares rurales. Los resultados indican que la fuerza principal detrás de la reducción de la pobreza ha sido el crecimiento económico general de la economía, debido a las condiciones macroeconómicas favorables durante el periodo de estudio. Estos efectos de crecimiento beneficiaron a casi todos los sectores rurales, y dieron lugar a la disminución de la pobreza rural extrema, especialmente entre los agricultores de papas y de maíz. En parte, estos agricultores probablemente se beneficiaron de la apertura de los mercados agrícolas, que es lo que podría haber provocado un aumento de los precios al productor en tiempos de altos precios mundiales de los alimentos. Sin embargo, los resultados también sugieren que para una gran parte de la población más pobre existían barreras de entrada a la hora de poder participar en el empleo asalariado fuera de la agricultura o en la producción de cultivos de alto valor. Esto podría explicarse por la falta de acceso a unos activos importantes: por ejemplo, el nivel de educación de los pobres era apenas mejor en 2012 que en 2004; y también las dotaciones de tierra y de mano de obra, sobre todo de los productores pobres de maíz y patata, disminuyeron entre 2004 y 2012. Esto lleva a la conclusión de que aún hay margen para aplicar políticas para facilitar el acceso a estos activos, que podría contribuir a la erradicación de la pobreza rural. La tesis concluye que el comercio agrícola puede ser un importante medio para abastecer una población mundial creciente y más rica con una cantidad suficiente de calorías. Para evitar adversos efectos ambientales e impactos negativos para los consumidores y de los productores pobres, el enfoque debe centrarse en las mejoras de la productividad agrícola, teniendo en cuenta los límites ambientales y ser socialmente inclusivo. En este sentido, será indispensable seguir desarrollando soluciones tecnológicas que garanticen prácticas de producción agrícola minimizando el uso de recursos naturales. Además, para los pequeños pobres agricultores será fundamental eliminar las barreras de entrada a los mercados de exportación que podría tener efectos indirectos favorables a través de la adopción de nuevas tecnologías alcanzables a través de mercados internacionales. ABSTRACT The world is in a state of rapid transition. Ongoing globalization, population growth, rising living standards and increasing urbanization, accompanied by changing dietary patterns throughout the world, are increasing the demand for food. Together with more open trade regimes, this has triggered growing international agricultural trade during the last decade. For many Latin American countries, which are gifted with relative natural resource abundance, these trends have fueled rapid export growth of primary goods. In just 30 years, the Latin American agricultural market share has almost doubled from 10% in 1980 to 18% in 2010. These market developments have given rise to a debate around a number of crucial issues related to the role of agricultural trade for global food security, for the environment or for poverty reduction in developing countries. This thesis uses an integrated framework to analyze a broad array of possible impacts related to transforming agricultural and rural markets in light of globalization, and in particular of increasing trade activity. Specifically, the following issues are approached: First, global food production will have to rise substantially by the year 2050 to meet effective demand of a nine billion people world population which poses major challenges to food production systems. Doing so without compromising environmental integrity in exporting regions is an even greater challenge. In this context, the thesis explores the effects of future global trade liberalization on food security indicators in different world regions and on a variety of environmental indicators at different scales in Latin America and the Caribbean, in due consideration of different future agricultural production practices. The International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) –a global dynamic partial equilibrium model of the agricultural sector developed by the International Food Policy Research Institute (IFPRI)– is applied to run different future production scenarios, and agricultural trade regimes out to 2050. Model results are linked to biophysical models, used to assess changes in water footprints and water quality, as well as impacts on biodiversity and carbon stocks from land use change by 2050. Results indicate that further trade liberalization is crucial for improving food security globally, but that it would also lead to more environmental pressures in some regions across Latin America. Contrasting land expansion versus more intensified agriculture shows that productivity improvements are generally superior to agricultural land expansion, from an economic and environmental point of view. Most promising for achieving food security and environmental goals, in equal measure, is the sustainable intensification scenario. However, the analysis shows that there are trade-offs between environmental and food security goals for all agricultural development paths. Second, in light of the recent food price crisis of 2007/08, the thesis looks at the impacts of increasing agricultural market integration on food price transmission from global to domestic markets in six Latin American countries, namely Argentina, Brazil, Chile, Colombia, Mexico and Peru. To identify possible cointegrating relationships between the domestic food consumer price indices and world food price levels, subject to different degrees of agricultural market integration in the six Latin American countries, a single equation error correction model is used. Results suggest that global agricultural market integration has led to different levels of price path-through in the studied countries. Especially in the short-run, transmission rates depend on the degree of trade openness, while in the long-run transmission rates are high, but largely independent of the country-specific trade regime. Hence, under world price shocks more trade openness brings with it more price instability in the short-term and the resulting persistence in the long-term. However, these findings do not necessarily verify the usefulness of trade policies, often applied by governments to buffer such price shocks. First, because there is a considerable risk of price volatility due to domestic supply shocks if self-sufficiency is promoted. Second, protectionism bears the risk of excluding a country from participating in beneficial high-value agricultural supply chains, thereby hampering economic development. Nevertheless, to reduce households’ vulnerability to sudden and large increases of food prices, effective policies to buffer food price shocks should be put in place, but must be carefully planned with the required budget readily available. Third, globalization affects the structure of an economy and, by different means, the distribution of income in a country. Peru serves as an example to dive deeper into questions related to changes in the income distribution in rural areas. Peru, a country being increasingly integrated into global food markets, experienced large drops in extreme rural poverty, but persistently high rates of moderate rural poverty and rural income inequality between 2004 and 2012. The thesis aims at disentangling the driving forces behind these dynamics by using a microsimulation model based on rural household income generation models. Results provide evidence that the main force behind poverty reduction was overall economic growth of the economy due to generally favorable macroeconomic market conditions. These growth effects benefited almost all rural sectors, and led to declines in extreme rural poverty, especially among potato and maize farmers. In part, these farmers probably benefited from policy changes towards more open trade regimes and the resulting higher producer prices in times of elevated global food price levels. However, the results also suggest that entry barriers existed for the poorer part of the population to participate in well-paid wage-employment outside of agriculture or in high-value crop production. This could be explained by a lack of sufficient access to important rural assets. For example, poor people’s educational attainment was hardly better in 2012 than in 2004. Also land and labor endowments, especially of (poor) maize and potato growers, rather decreased than increased over time. This leads to the conclusion that there is still scope for policy action to facilitate access to these assets, which could contribute to the eradication of rural poverty. The thesis concludes that agricultural trade can be one important means to provide a growing and richer world population with sufficient amounts of calories. To avoid adverse environmental effects and negative impacts for poor food consumers and producers, the focus should lie on agricultural productivity improvements, considering environmental limits and be socially inclusive. In this sense, it will be crucial to further develop technological solutions that guarantee resource-sparing agricultural production practices, and to remove entry barriers for small poor farmers to export markets which might allow for technological spill-over effects from high-value global agricultural supply chains.

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Forest connectivity restoration is a major goal in natural resource planning. Given the high amount of abandoned cultivated lands, setting efficient methods for the reforestation of agricultural lands offers a good opportunity to face this issue. However, reforestations must be carefully planned, which poses two main challenges. In first place, to determine those agricultural lands that, once reforested, would meet more effectively the planning goals. As a further step, in order to grant the success of the activity, it is fairly advisable to select those tree species that are more adapted to each particular environment. Here we intend to give response to both requirements by proposing a sequential and integrated methodology that has been implemented in two Spanish forest districts, which are formed by several landscape types that were previously defined and characterized. Using the software Conefor Sensinode, a powerful tool for quantifying habitat availability that is based on graph theory concepts, we determined the landscapes where forest planning should have connectivity as a major concern and, afterwards, we detected the agricultural patches that would contribute most to enhance connectivity if they were reforested. The subsequent reforestation species assessment was performed within these priority patches. Using penalized logistic regressions we fitted ecological niche models for the Spanish native tree species. The models were trained with species distribution data from the Spanish Forest Map and used climatic and lithological variables as predictors. Model predictions were used to build ordered lists of suitable species for each priority patch. The lists include dominant and non dominant tree species and allow adding biodiversity goals to the reforestation planning. The result of this combined methodology is a map of agricultural patches that would contribute most to uphold forest connectivity if they were reforested and a list of suitable tree species for each patch ordered by occurrence probability. Therefore the proposed methodology may be useful for suitable and efficient forest planning and landscape designing.

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El suelo es un importante recurso natural que necesita ser preservado y mejorado para permitirle mantener su calidad y capacidad productiva, para ello se deben proponer y aplicar prácticas sostenibles que permitan recuperar aquellos suelos degradados por un mal manejo del hombre, como por ejemplo la salinización. El objetivo planteado fue evaluar la biorecuperación de un suelo con problemas salino-sódico con la aplicación de dos proporciones (1,5 y 3% (p/p)) de tres enmiendas orgánicas: compost, vermicompost sólido y Lemna mesclados o no con el 100% de los requerimientos de fosfoyeso, generándose 15 tratamientos (incluyendo tres controles). La evaluación se realizó a través de tres ensayos: 1. Columnas simuladas de suelo. 2. Evolución de CO2 y 3. Crecimiento de plántulas de tomate. El suelo objeto de estudio está clasificado my como Fluventic Haplustepts, y fue tomado de una zona de la Hacienda Alto Viento, con una latitud de 10° 2' 15 N y una longitud de 72 ° 34' 15 W, en el estado de Zulia – Venezuela. Se tomó una muestra compuesta por 20 submuestras de 20 cm de profundidad del área problema, se secó al aire (2,3% de humedad), se tamizó y homogenizó. El suelo y las enmiendas orgánicas fueron caracterizadas. Los materiales orgánicos; compost y vermicompost fueron procesados en la misma Hacienda con el uso de estiércol de ganado bovino; la Lemna fue recolectada de orillas del Lago de Maracaibo en la ciudad de Maracaibo. El suelo se mezcló a las proporciones indicadas se le midió respiración basal y el efecto sobre la germinación de semillas de tomate y se empaquetó en un tubo de polietileno de 7,1 cm de diámetro y 70 a 90 cm de longitud, según la altura de la mezcla del suelo con la enmienda. El fondo de cada columna fue rellenado con 40 cm de arena lavada para facilitar el drenaje. En cada columna se utilizó la misma cantidad de suelo (1055 mg), la altura que ocupó dentro de las columnas dependió del tipo de enmienda orgánica y su proporción, la cual modificó la Da del suelo (1,328±0,05 g•cm-3). La altura dentro de la columna varió desde 20 cm para el suelo sin enmienda hasta 38,33±0,8 cm para el suelo enmendado con Lemna al 3,0%. Transcurrido el periodo de tres meses tiempo en el cual el suelo enmendado y colocado en las columnas fue lavado con una cantidad de agua que equivalente a la tasa de infiltración, la cual se calculó a partir de la precipitación anual de la zona y las perdidas por evaporación y escorrentía; se fraccionó en tres secciones de 7, 7 y 6 cm de longitud, y el suelo de cada fracción se secó al aire y se tamizó, y se le midió CEextr, pH, cationes en solución y cationes extraíbles para calcular el RAS y el PSI. Se tomó una cantidad equivalente de cada sección para conformar una muestra de 50 g de suelos a los cuales se le midió respiración basal e igualmente se tomó suelo para evaluar la germinación y crecimiento de plántulas de tomate. Se detectaron diferencias significativa (p<0,05) entre tratamientos, según la prueba de Tukey, para la variables evaluadas, aunque no hubo diferencias entre las proporciones ni entre la utilización del fosfoyeso mezclado con las enmiendas orgánicas. La enmienda que mostró menos potencial en la bio remediación fue la Lemna por sus altos contenidos de Na+. La metodología de las columnas simuladas del suelo, bajo las condiciones de estudio, no fue del todo adecuada para evaluar la bio remediación debido que en el suelo control por efecto de la aplicación de agua también hubo recuperación del mismo por su disminución en el la CE, RAS y PSI y en algunas variables su recuperación fue mayor que en aquellos enmendados con Lemna. Tomando en la respuesta del cultivo la mejor enmienda fue el vermicompost Abstract The soil is an important natural resource that needs to be preserved and improved to maintain its quality and production potential. Therefore, it is necessary to propose and apply sustainable practices that permit the recovery of soils that have been degraded by inadequate management, among these saline soils. The objective of this study was to evaluate the bioremediation of a saline-sodic soil through the application of two proportions (1,5 and 3% (p/p) of three organic amendments: compost, vermicompost and Lemna, mixed or not with gypsum phosphate, resulting in 15 treatments (including 3 controls). The evaluation was conducted through three tests: 1. Simulated soil columns. 2. Evolution of CO2 and 3. Growth of tomato seedlings The soil under evaluation was classified as Fluventic Haplustepts and was collected from the Alto Viento farm located at 10° 2' 15 North Latitude and 72° 34' 15 West longitude, in Zulia State, Venezuela. A composite soil sample, integrated of 20 subsamples taken to a depth of 20 cm collected in the problem area, was air dried (2.3 % moisture), sieved and homogenized. Soil and organic amendments were characterized. Organic material for the compost and vermicompost were obtained on the farm using cattle manure, whereas the Lemna was collected from the shores of Lake Maracaibo outside Maracaibo city. The soil was mixed in the above-mentioned proportions and its baseline respiration rate and effect on the germination of tomato seeds were recorded. Soil was packed in a PVC pipe (7,1 cm diameter and 70-90 cm length) to simulate a soil column. The bottom of each column was filled out with 40 cm of washed sand to facilitate drainage. The same amount of soil was used in each column (1,055 mg), but the height of the column varied according to the organic amendment and its proportion, which modified the apparent density of the soil (1,328±0,05 g•cm-3). The height of each column varied from 20 cm for the soil without amendment to 38,33±0,8 cm for the soil with 3% Lemna. After three months, the soil was treated with water (using the equivalent of the problem area infiltration rate), and was divided into three sections (7, 7 and 6 cm length). The soil from each section was air dried, sieved and its cationic exchange capacity, pH, cation solutions and extractable cations were measured to estimate RAS and PSI. An equivalent portion of each section was collected to compose a 50 g soil sample, and baseline respiration rate and tomato seedlings growth were recorded. Statistical differences (p<0,05) were observed among treatments for the variables under evaluation. Tukey test showed no differences among the proportions of organic amendments nor with the addition of gypsum phosphate to the organic amendments. The amendment which showed the lowest bioremediation potential was the Lemna, as a result of its high Na+ concentration. Under the conditions of this study, the soil column methodology used showed limitations to evaluate bioremediation because the control soil column, after being rinsed with water, also showed improvements as CE, RAS and PSI values were reduced. For some variables, the improvement noted in the control soil column surpassed those obtained with the soil amended with Lemna. Based on the best crop response amendment was vermicompost 3%.

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Purpose – The strategic management literature lacks a comprehensive explanation as to why seemingly similar business models in the same industry perform differently. This paper strives to explain this phenomenon. Design/methodology/approach – The model is conceptualized and accompanied by a case study on the airline industry to explain knowledge brokerage that creates value from the effective utilization of knowledge resources acquired from intra- and inter-firm environments. Findings – The model explains a cyclical view of business model flexibility in which the knowledge-based resource accumulation of the business model is spread across the intra- and inter-firm environments. Knowledge brokerage strategies from the inter- and intra-firm environments result in improved performance of the business model. The flexibility that the business model acquires is determined by how efficiently resource accumulation is aligned with its external environment. Originality/value – The paper effectively integrates the concepts of knowledge brokerage and business models from a resource accumulation-based view and simultaneously arrives at the performance heterogeneity of seemingly similar business models within the same industry. It has performance implications for firms that start out without any distinct resources of their own, or that use an imitated business model, to attain better performance through business model evolution aligned with successful knowledge brokerage strategies. It adds to the resource accumulation literature by explaining how resources can be effectively acquired to create value.

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Natural regeneration is an ecological key-process that makes plant persistence possible and, consequently, it constitutes an essential element of sustainable forest management. In this respect, natural regeneration in even-aged stands of Pinus pinea L. located in the Spanish Northern Plateau has not always been successfully achieved despite over a century of pine nut-based management. As a result, natural regeneration has recently become a major concern for forest managers when we are living a moment of rationalization of investment in silviculture. The present dissertation is addressed to provide answers to forest managers on this topic through the development of an integral regeneration multistage model for P. pinea stands in the region. From this model, recommendations for natural regeneration-based silviculture can be derived under present and future climate scenarios. Also, the model structure makes it possible to detect the likely bottlenecks affecting the process. The integral model consists of five submodels corresponding to each of the subprocesses linking the stages involved in natural regeneration (seed production, seed dispersal, seed germination, seed predation and seedling survival). The outputs of the submodels represent the transitional probabilities between these stages as a function of climatic and stand variables, which in turn are representative of the ecological factors driving regeneration. At subprocess level, the findings of this dissertation should be interpreted as follows. The scheduling of the shelterwood system currently conducted over low density stands leads to situations of dispersal limitation since the initial stages of the regeneration period. Concerning predation, predator activity appears to be only limited by the occurrence of severe summer droughts and masting events, the summer resulting in a favourable period for seed survival. Out of this time interval, predators were found to almost totally deplete seed crops. Given that P. pinea dissemination occurs in summer (i.e. the safe period against predation), the likelihood of a seed to not be destroyed is conditional to germination occurrence prior to the intensification of predator activity. However, the optimal conditions for germination seldom take place, restraining emergence to few days during the fall. Thus, the window to reach the seedling stage is narrow. In addition, the seedling survival submodel predicts extremely high seedling mortality rates and therefore only some individuals from large cohorts will be able to persist. These facts, along with the strong climate-mediated masting habit exhibited by P. pinea, reveal that viii the overall probability of establishment is low. Given this background, current management –low final stand densities resulting from intense thinning and strict felling schedules– conditions the occurrence of enough favourable events to achieve natural regeneration during the current rotation time. Stochastic simulation and optimisation computed through the integral model confirm this circumstance, suggesting that more flexible and progressive regeneration fellings should be conducted. From an ecological standpoint, these results inform a reproductive strategy leading to uneven-aged stand structures, in full accordance with the medium shade-tolerant behaviour of the species. As a final remark, stochastic simulations performed under a climate-change scenario show that regeneration in the species will not be strongly hampered in the future. This resilient behaviour highlights the fundamental ecological role played by P. pinea in demanding areas where other tree species fail to persist.

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En claro alineamiento con estrategias de sostenibilidad en el uso de recursos naturales en un escenario constante de aumento de la demanda energética mundial, el desarrollo de la tecnología energética en la Historia de la Especie Humana muestra un vector de evolución permanente desde su origen en el sentido del desarrollo y uso de nuevas fuentes energéticas con la explotación de recursos naturales de manera más eficiente: soluciones energéticas con aumento de la densidad energética (exoenergía de proceso por unidad de masa de recurso natural). Así el cambio de escala en la demanda de explotación del Litio como recurso natural se viene presentando en la última década ligada al desarrollo del mercado de las baterías "ion-Litio" y los requisitos de combustible (Deuterio y Litio) en el camino de la fusión nuclear como opción energética próxima. El análisis anticipado de las demandas sinérgicas a escala de ambos mercados aparece de enorme interés prospectivo en sus aspectos técnicos: (1) tecnologías de base para la extracción mineral y de agua marina y (2) su enriquecimiento isotópico (de interés sinérgico; 7Li para baterías eficientes ion-litio; 6Li como regenerador de tritio en ciclo de combustible en fusión nuclear) a la vez que en sus aspectos económicos. Este Proyecto realiza: (1) un ejercicio de análisis prospectivo de la demanda y de mercado para el enriquecimiento 6Li/7Li para las próximas décadas, (2) se califican los desarrollos tecnológicos específicos que van a poder permitir la producción a escala conforme a la demanda; (3) se selecciona y califica una técnica [de centrifugación / termo-difusión/ destilación combinada] como opción tecnológicamente viable para la producción a escala de formas litiadas; (4) se propone un diseño conceptual de planta de producción y finalmente (5) propone un estudio de viabilidad para la demostración de proceso y construcción de dicha planta de demostración de la nueva capacidad tecnológica. ABSTRACT Clearly aligned with sustainability strategies under growing world energy demand in the use of natural resources the development of energy technology in the history of the human species shows a vector of ongoing evolution from its origin in the sense of the development and use of new energy sources with the exploitation of natural resources in a more efficient manner. The change of scale in the demand for exploitation of Lithium as a natural resource appears during the last decade as bound to the deployment of "lithium-ion" batteries market and to the Nuclear Fusion fuels (deuterium and lithium) supply scaled demands. The prospective analysis of demands to scale in both markets appears in scene with huge prospective interest in its technical aspects: (1) base technologies for mineral and water marine extraction (2) its isotopic enrichment (synergistic interests; 7Li efficient battery Li-ion; 6Li as fusion nuclear fuel breeder (tritium) as well as in its economic aspects. This Project: (1) propose a prospective analysis exercise of the synergistic supply demand for coming decades for the enrichment of 6Li and 7Li, (2) qualifies specific technological developments ongoing to respond to supply demand; (3) select and qualifies an appropriate technique [combined centrifugation/thermo-diffusion/distillation] as technologically viable option for lithiated forms scaled-production; (4) proposes a conceptual design of production plant based on the technique and finally (5) proposes a feasibility study for the process demonstration and construction of this new technological capability Demonstration Plant.

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Natural regeneration-based silviculture has been increasingly regarded as a reliable option in sustainable forest management. However, successful natural regeneration is not always easy to achieve. Recently, new concerns have arisen because of changing future climate. To date, regeneration models have proved helpful in decision-making concerning natural regeneration. The implementation of such models into optimization routines is a promising approach in providing forest managers with accurate tools for forest planning. In the present study, we present a stochastic multistage regeneration model for Pinus pinea L. managed woodlands in Central Spain, where regeneration has been historically unsuccessful. The model is able to quantify recruitment under different silviculture alternatives and varying climatic scenarios, with further application to optimize management scheduling. The regeneration process in the species showed high between-year variation, with all subprocesses (seed production, dispersal, germination, predation, and seedling survival) having the potential to become bottlenecks. However, model simulations demonstrate that current intensive management is responsible for regeneration failure in the long term. Specifically, stand densities at rotation age are too low to guarantee adequate dispersal, the optimal density of seed-producing trees being around 150 stems·ha−1. In addition, rotation length needs to be extended up to 120 years to benefit from the higher seed production of older trees. Stochastic optimization confirms these results. Regeneration does not appear to worsen under climate change conditions; the species exhibiting resilience worthy of broader consideration in Mediterranean silviculture.

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El proceso de cambio de una sociedad industrial a una sociedad del conocimiento, que experimenta el mundo globalizado en el siglo XXI, induce a las empresas y organizaciones a desarrollar ventajas competitivas y sostenibles basadas en sus activos intangibles, entre los cuales destacan los sistemas de gestión en general y los sistemas de gestión de la calidad (SGC) en particular. Las organizaciones dedicadas a la producción de petróleo están influenciadas por dicha tendencia. El petróleo es un recurso natural con reservas limitadas, cuya producción y consumo ha crecido progresivamente, aportando la mayor cuota (35 %) del total de la energía que se consume en el mundo contemporáneo, aporte que se mantendrá hasta el año 2035, según las previsiones más conservadoras. Por tanto, se hace necesario desarrollar modelos de producción innovadores, que contribuyan a la mejora del factor de recobro de los yacimientos y de la vida útil de los mismos, al tiempo que satisfagan los requerimientos de producción y consumo diarios de los exigentes mercados globales. El objeto de esta investigación es el desarrollo de un modelo de gestión de la calidad y su efecto en el desempeño organizacional, a través del efecto mediador de los constructos satisfacción del cliente interno y gestión del conocimiento en la producción de petróleo. Esta investigación de carácter explicativo, no experimental, transeccional y ex-postfacto, se realizó en la región petrolífera del lago de Maracaibo, al occidente de Venezuela, la cual tiene más de 70 años en producción y cuenta con yacimientos maduros. La población objeto de estudio fue de 369 trabajadores petroleros, quienes participaron en las mesas técnicas de la calidad, durante los meses de mayo y julio del año 2012, los cuales en su mayoría están en proceso de formación como analistas, asesores y auditores de los SGC. La técnica de muestreo aplicada fue de tipo aleatorio simple, con una muestra de 252 individuos. A la misma se le aplicó un cuestionario diseñado ad hoc, el cual fue validado por las técnicas de juicio de expertos y prueba piloto. El procedimiento de investigación se realizó a través de una secuencia, que incluyó la elaboración de un modelo teórico, basado en la revisión del estado del arte; un modelo factorial, sobre la base del análisis factorial de los datos de la encuesta; un modelo de regresión lineal, elaborado a través del método de regresión lineal simple y múltiple; un modelo de análisis de sendero, realizado con el software Amos 20 SPSS y finalmente, un modelo informático, realizado con el simulador Vensim PLE v.6.2. Los resultados obtenidos indican que el modelo teórico se transformó en un modelo empírico, en el cual, la variable independiente fue el SGC, la variable mediadora fue la integración de las dimensiones eliminación de la no conformidad, satisfacción del cliente interno y aprendizaje organizacional (ENCSCIAO) y la variable respuesta la integración de las dimensiones desempeño organizacional y aprendizaje organizacional (DOOA). Se verificó el efecto mediador del ENSCIAO sobre la relación SGC-DOOA con una bondad del ajuste, del 42,65%. En el modelo de regresión múltiple se encontró que las variables determinantes son eliminación de la no conformidad (ENC), conocimiento adquirido (CA) y conocimiento espontáneo (CE), lo cual fue corroborado con el modelo de análisis de sendero. El modelo informático se desarrolló empleando datos aproximados de una unidad de producción tipo, generándose cuatro escenarios; siendo el más favorable, aquel en el cual se aplicaba el SGC y variables relacionadas, reduciendo la desviación de la producción, incrementando el factor de recobro y ampliando la vida útil del yacimiento. Se concluye que la aplicación del SGC y constructos relacionados favorece el desempeño y la producción de las unidades de explotación de yacimientos petrolíferos maduros. Los principales aportes de la tesis son la obtención de un modelo de gestión de la producción de petróleo en yacimientos maduros, basado en los SGC. Asimismo, el desarrollo de un concepto de gestión de la calidad asociado a la reducción de la desviación de la producción petrolífera anual, al incremento del factor de recobro y al aumento de la vida útil del yacimiento. Las futuras líneas de investigación están orientadas a la aplicación del modelo en contextos reales y específicos, para medir su impacto y realizar los ajustes pertinentes. ABSTRACT The process of change from an industrial society to a knowledge-based society, which undergoes the globalized world in the twenty-first century, induces companies and organizations to develop a sustainable and competitive advantages based on its intangible assets, among which are noteworthy the management systems in general and particularly the quality management systems (QMS). Organizations engaged in oil production are influenced by said trend. Oil is a natural resource with limited reserves, where production and consumption has grown progressively, providing the largest share (35%) of the total energy consumed in the contemporary world, a contribution that will remain until the year 2035 according to the more conservative trust estimations. Therefore, it becomes necessary to develop innovative production models which contribute with the improvement of reservoirs´ recovery factor and the lifetime thereof, while meeting the production requirements and daily consumption of demanding global markets. The aim of this research is to develop a model of quality management and its effect on organizational performance through the mediator effect of the constructs, internal customer satisfaction and knowledge management in oil production. This research of explanatory nature, not experimental, transactional and expos-facto was carried out in the oil-region of Maracaibo Lake located to the west of Venezuela, which has more than 70 years in continuous production and has mature reservoirs. The population under study was 369 oil workers who participated in the technical quality workshops, during the months of May and July of 2012, the majority of which were in the process of training as analysts, consultants and auditors of the QMS. The sampling technique applied was simple random type. To a sample of 252 individuals of the population it was applied an ad hoc designed questionnaire, which was validated by the techniques of expert judgment and pilot test. The research procedure was performed through a sequence, which included the elaboration of a theoretical model, based on the review of the state of the art; a factorial model with based on factorial analysis of the survey data; a linear regression model, developed through the method of simple and multiple linear regression; a structural equation model, made with software °Amos 20 SPSS° and finally, a computer model, performed with the simulator Vensim PLE v.6.2. The results indicate that the theoretical model was transformed into an empirical model, in which the independent variable was the QMS, the mediator variable was the integration of the dimensions: elimination of non-conformity, internal customer satisfaction and organizational learning (ENCSCIAO) and the response variable the integration of the dimensions, organizational performance and learning organizational (DOOA). ENSCIAO´s mediator effect on the relation QMS-DOOA was verified with a goodness of fit of 42,65%. In the multiple regression model was found to be the determining variables are elimination of nonconformity (ENC), knowledge acquired (CA) and spontaneous knowledge (EC), which was verified with the structural equation model. The computer model was developed based on approximate data of an oil production unit type, creating four (04) scenarios; being the most favorable, that one which it was applied the QMS and related variables, reducing the production deviation, increasing the recovery factor and extending the lifetime of the reservoir. It is concluded that QMS implementation powered with the related constructs, favors performance and production of mature oilfield of exploitation reservoirs units. The main contributions of this thesis are obtaining a management model for oil production in mature oilfields, based on QMS. In addition, development of a concept of quality associated to reduce the annual oil production deviation, increase the recovery factor and increase oilfield lifetime. Future lines of research are oriented to the implementation of this model in real and specific contexts to measure its impact and make the necessary adjustments that might take place.

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Electrical power systems are changing their traditional structure, which was based on a little number of large generating power plants placed at great distances from loads by new models that tend to split the big production nodes in many smaller ones. The set of small groups which are located close to consumers and provide safe and quality energy is called distributed generation (DG). The proximity of the sources to the loads reduces losses associated with transportation and increases overall system efficiency. DG also favors the inclusion of renewable energy sources in isolated electrical systems or remote microgrids, because they can be installed where the natural resource is located. In both cases, as weak grids unable to get help from other nearby networks, it is essential to ensure appropriate behavior of DG sources to guarantee power system safety and stability. The grid codes sets out the technical requirements to be fulfilled for the sources connected in these electrical networks. In technical literature it is rather easy to find and compare grid codes for interconnected electrical systems. However, the existing literature is incomplete and sparse regarding isolated electrical systems and this happens due to the difficulties inherent in the pursuit of codes. Some countries have developed their own legislation only for their island territory (as Spain or France), others apply the same set of rules as in mainland, another group of island countries have elaborated a complete grid code for all generating sources and some others lack specific regulation. This paper aims to make a complete review of the state of the art in grid codes applicable to isolated systems, setting the comparison between them and defining the guidelines predictably followed by the upcoming regulations in these particular systems.