On the potential contribution of rooftop PV to a sustainable electricity mix: the case of Spain

This work evaluates the potential contribution of rooftop PV to the future electricity mix. Several sustainable scenarios are considered, each comprising different shares of centralized renewables, rooftop PV and storage. For each generation scenario, the storage capacity that balances the net hourly demand is determined, and the portfolio combination that minimizes the cost of supplying electricity is obtained. The analysis is applied to mainland Spain, using public information and detailed granular models, both in time (hourly resolution) and space (municipal level). For the Spanish case, when the flexibility of hydro and biomass generation is taken into account, the least-cost portfolio involves rather modest storage capacities, in the order of daily rather than seasonal values. This shows that a sustainable, almost emissions-free electricity system for Spain is possible, at a cost that can be even lower than current wholesale market prices.Comment: 7 tables & 11 figures in the main body (24 pages), and 13 pages for the supplementary material, wit

Persistent homology for 3D reconstruction evaluation

Space or voxel carving is a non-invasive technique that is used to produce a 3D volume and can be used in particular for the reconstruction of a 3D human model from images captured from a set of cameras placed around the subject. In [1], the authors present a technique to quantitatively evaluate spatially carved volumetric representations of humans using a synthetic dataset of typical sports motion in a tennis court scenario, with regard to the number of cameras used. In this paper, we compute persistent homology over the sequence of chain complexes obtained from the 3D outcomes with increasing number of cameras. This allows us to analyze the topological evolution of the reconstruction process, something which as far as we are aware has not been investigated to date

Planeacion Financiera: Aplicación de las herramientas de la planeacion financiera en la Empresa Químicas Veterinarias S,A. en el periodo 2015-2016

Con esta investigación abordamos problemas de liquidez y rentabilidad que se estaban presentando en la empresa Químicas Veterinarias, S.A. con el objetivo de aplicar las principales herramientas de planeación financiera y explicar la importancia y utilidad de las mismas en toda empresa. Para llevar a cabo esta investigación, se utilizó la técnica de investigación documental y bibliográfica, además se revisó los principales Documentos de Gestión e información financiera de la empresa Químicas Veterinarias, S.A que se abordó en el caso práctico. Se logró así comprender en más detalle la problemática presentada por la Empresa. También se determinó las causas que generaron el problema y las posibles soluciones. Como solución, se implementaron las principales herramientas de planeación financiera como son: Presupuesto Maestro, Flujo de Caja Presupuestado y Estados Financieros Proforma, logrando así dar solución a los problemas de Liquidez con la Planeación del Efectivo y mejorar la Rentabilidad con la Planeación de las Utilidades a través del control y planificación de los gastos al analizar el efecto e importancia que los mismos presentaban en los Estados Financieros Proforma. Se puede concluir que las herramientas de planeación financiera son un instrumento de vital importancia en toda empresa si se quiere prolongar la existencia de la misma y si se quiere mantener un crecimiento y desarrollo sostenibles, puesto que con la planeación financiera adecuada se pueden alcanzar los objetivos estratégicos y mantener la “salud” financiera de empresa

Ecohydrology of aspen and eucalyptus plantations: considerations for management

Forecast scenarios predict an increase in the demand of alternative sources of energy during the coming decades, such as woody biomass crops (WBC). WBC have the potential to become a major challenge for the next generation of researchers, policymakers and land managers. However, the current rationale for promoting plant-based over petroleum-based energy sources emphasizes the benefits of reduced carbon dioxide and other emissions, while giving less attention to potential impacts to water resources. It is well documented in the scientific literature that trees use large amounts of water for metabolic needs. Water use at the tree and ecosystem level has always been of scientific interest, however, the potential impact of water use in bioenergy plantations is often considered a “possible environmental impact”. Thus, understanding the ecological implications of water use in WBC is essential for their sustainable development. The general goal of my research was to assess potential ecohydrological impacts associated with the production of biomass for bioenergy from aspen (Populus tremuloides Mich.) in Wisconsin, USA, and eucalyptus (Eucalyptus grandis) plantations in Entre Rios, Argentina. My doctoral research was part of a large international interdisciplinary NSF-PIRE research project that examined the impacts, barriers and opportunities related to bioenergy production across the Americas (USA, Mexico, Brazil, Argentina). We selected plantation ages within the most common rotation cycles for each species. In Wisconsin, we studied three sites, a 10- and a 24-year-old (YO) coppice plantations, and a reference 34 YO mature forest. In Argentina, we studied two 1 YO plantations one at high and one at regular density, a 4 YO, a 10 YO plantation, and a reference grassland. This was a unique study to determine annual water use based on a combination of tree-level measurements of water use using sap flow sensors, and deterministic models of potential evapotranspiration. We validated two sap flow methods (heat dissipation and heat ratio), and validated a third method (maximum heat ratio) that is capable of measuring with precision high and low sap flux densities (Fd, cm3 cm-2 cm1). According to the results from the validation studies, we were able to estimate tree-level water use within a 7% error margin (estimated as the difference between observed and estimated sap flow in L h-1) using heat ratio and maximum heat ratio methods, without generating species-specific parameters. However, using the heat dissipation method, the average estimation error without species-specific parameters was -53%, and improved to 5% once species-specific parameters were generated. Validating the maximum heat ratio method, allowed us to estimate Fd in young trees, which are often excluded from chronosequence studies due to their high Fd. Our estimates of Fd at different plantation ages, allowed us to extrapolate from the tree to the site level, using real tree-level response to various environmental variables. Our analysis of P. tremuloides and E. grandis offered contrasting results. In P. tremuloides plantations, water use at the site level generally increased with age, even when site density decreased over time (from approx. 6500 to 1900 from 10 to 34 YO). We observed that young plantations (10 YO) used 80% of the annual water early in the growing season, compared to a 45% for the same period in the Mid-aged and Mature plantations. Site effects, specifically soil type and the resulting soil saturation (S), had a significant effect on T estimates. After modeling the effects of S, creating two artificial scenarios (e.g. limited and non-limited S) the 10 YO site showed the highest sensibility to changes in S, while the 34 YO mature site was the least affected. Average stand transpiration by site considering the effects of S increased with age, which supported our hypothesis regarding the relationship between stand age and stand T. However, the relationship between stand T was not constant across seasons, which according to our results might be caused by a higher hydraulic stress observed in the 10YO site, compared to the other two sites. On eucalyptus plantations, when the density remained constant, stand T decreased with plantation age, reaching maximum water use rates at around 4 YO and declining afterwards for the remainder of the typical 15 YO rotation cycles. Due to similar site conditions in terms of soil characteristics, we did not observe a strong site effect. Our experimental site at high density (e.g., double of a regular site) showed an increase in average site T of 50%, and both 1 YO sites presented an opportunistic pattern in water use, increasing when soil water was available, but decreasing significantly when soil moisture was limiting. Finally, in both plantations we observed that reference evapotranspiration, estimated with the Penman-Monteith equation, was a poor predictor of water use in young plantations. We associate these results to the seasonal patterns of water use in young plantations. Within the context of bioenergy production, our results provide ample evidence for the importance of water use in bioenergy plantations in the early stages of feedstock production. We also show that plantation density in fast and slow growing species, impacts the way trees respond to water availability in the soil

The contribution of the United States Supreme Court and the European Court of justice in the vertical and horizontal allocation of power

PhDThis thesis explores the contribution of the US Supreme Court (USSC) and the European Court of Justice (ECJ) in the vertical and horizontal allocation of power. Said differently, it answers the two following questions: How do both Courts draw the line between the realm of politics and judicial process? How do they allocate power between the Union and its component States? After examining standing, the political question doctrine, negative and positive integration and liability in damages on both sides of the Atlantic, it is concluded that both Courts should not always look for “substantive” constitutional benchmarks. The reason lies in that sometimes the latter may turn to be either questions deemed too political for judicial resolution or insufficient to control congressional or Community legislative powers. Additionally, the judicial department should also pay due regard to a “process” review. This type of review would operate at two levels. At first stage, Courts should solve flaws in the procedure by which the political institutions adopt their decisions. For instance, this would be the case where procedures neglect “discrete and insular” minorities, or where they entrench incumbent political majorities. Thus, judicial review would be principled upon understanding “democracy” as an intangible value that cannot succumb to majoritarian pressures. At a second stage, Courts should also examine whether, in their deliberations, political actors pay due account to all interests at stake, particularly, to those not represented in the political process