887 resultados para Availability and efficiency
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In order to verify Point-Centered Quarter Method (PCQM) accuracy and efficiency, using different numbers of individuals by per sampled area, in 28 quarter points in an Araucaria forest, southern Paraná, Brazil. Three variations of the PCQM were used for comparison associated to the number of sampled individual trees: standard PCQM (SD-PCQM), with four sampled individuals by point (one in each quarter), second measured (VAR1-PCQM), with eight sampled individuals by point (two in each quarter), and third measuring (VAR2-PCQM), with 16 sampled individuals by points (four in each quarter). Thirty-one species of trees were recorded by the SD-PCQM method, 48 by VAR1-PCQM and 60 by VAR2-PCQM. The level of exhaustiveness of the vegetation census and diversity index showed an increasing number of individuals considered by quadrant, indicating that VAR2-PCQM was the most accurate and efficient method when compared with VAR1-PCQM and SD-PCQM.
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Forest biomass represents a geographically distributed feedstock, and geographical location affects the greenhouse gas (GHG) performance of a given forest-bioenergy system in several ways. For example, biomass availability, forest operations, transportation possibilities and the distances involved, biomass end-use possibilities, fossil reference systems, and forest carbon balances all depend to some extent on location. The overall objective of this thesis was to assess the GHG emissions derived from supply and energy-utilization chains of forest biomass in Finland, with a specific focus on the effect of location in relation to forest biomass’s availability and the transportation possibilities. Biomass availability and transportation-network assessments were conducted through utilization of geographical information system methods, and the GHG emissions were assessed by means of lifecycle assessment. The thesis is based on four papers in which forest biomass supply on industrial scale was assessed. The feedstocks assessed in this thesis include harvesting residues, smalldiameter energy wood and stumps. The principal implication of the findings in this thesis is that in Finland, the location and availability of biomass in the proximity of a given energyutilization or energy-conversion plant is not a decisive factor in supply-chain GHG emissions or the possible GHG savings to be achieved with forest-biomass energy use. Therefore, for the greatest GHG reductions with limited forest-biomass resources, energy utilization of forest biomass in Finland should be directed to the locations where most GHG savings are achieved through replacement of fossil fuels. Furthermore, one should prioritize the types of forest biomass with the lowest direct supply-chain GHG emissions (e.g., from transport and comminution) and the lowest indirect ones (in particular, soil carbon-stock losses), regardless of location. In this respect, the best combination is to use harvesting residues in combined heat and power production, replacing peat or coal.
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ABSTRACT Weeds have the potential to dramatically interfere in cassava cultivation, reducing its productive potential; however, there are few studies on the selective herbicides in this crop. Therefore, the objective was to evaluate in this work the selectivity and efficiency of sulfentrazone in cassava crops grown in sandy and clayey soils. Two experiments were carried out: The first one was carried out in sandy soil conditions in the conventional system; and the second one was carried out in clayey soil conditions in the no-tillage system. The experimental design was a randomized block with four replications. The treatments consisted in doses of 250, 500, 750 and 1,000 g ha-1 of sulfentrazone, and weeded and non-weeded controls. Sulfentrazone application in cassava crops has linearly reduced the production of roots in a proportion of 0.0153 and 0.0107 t ha-1 at each increment in grams of the active ingredient, respectively. It was concluded that sulfentrazone was not selective for cassava crops grown both in sandy and in clayey soil; however, it was highly effective in weed control in both soils.
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The purpose of this research was to examine the most optimal way to arrange meetings and events management and source to pay –process in a global company. The research is a qualitative multi-method case study and is a commission from a global company. The theoretical framework of this research structures around two approaches. First approach focus on a purchasing strategy and management that shows the current role of procure-ment and introduce different ways to organize purchasing functions. Second approach focus on purchasing process management and improvement methods. Annual spend analyze, external and internal interviews and internal survey were done to gain compre-hensive knowledge about the current state of operations and possible solutions. Gathered data were then combined to theoretical framework in order to create optimal solution for the case company. Based on the research a source to pay –process and global policy for meeting and event category was created. The solution includes all relevant matters that are needed in order to secure efficient and profitable operations. The results show that optimal way to arrange meetings and events structures around standardized source to pay –processes, central-ized procurement, preferred supplier and clearly defined roles and responsibilities be-tween different stakeholders.
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Hematological status in rainbow trout, Salmo gairdneri, was examined in relation to eight combinations of three environmental fa ctors; temperature (5°, 20°C), oxygen availability «35%, >70% saturation) and photoperiod (16L:8D, 8L:16D) and evaluated by 3-factor analysis of variance. Hemog l obin and hematocrit , indicators of oxygenc arrying capacity increased significantly at the higher temperature, following exposure to hypoxia and in relation to reduced light period. Significant variations in mean corpuscular hemoglobin concentration were not detected. The effects of temperature and oxygen availability were more pronounced than that of photoperiod which was generally masked. Although oxygen availability and photoperiod did not interact with temperature, the interaction of the former fac tors was significant. Elec trophoresis revealed twelve hemoglobin isomorphs. Relative concentration changes were found in re lation to the factors c onsidered with temperature>hypoxia>photoperiod. Howeve r , in terms of absolute concentration, effects were hypoxia>temperature>photoperiod. Photoperiod effects were again masked by temperature and (or) hypoxia. Red cell +2 l eve ls of [CI ] and [Mg ], critical elements in the hemoglobin-oxygen affinity regulating system, were also significantly altered. Red cell CI +2 was influenced only by temperature ; Mg by temper ature and oxygen. No photoperiod influence on either ions was observed. Under nominal 'summer' conditions, these changes point to the likelihood of increases in oxygen-c arrying c apac ity coupled with low Hb-02 affinity adjustments which would be expected to increase oxygen delivery rates to their more rapidly metabolising tissues.
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We consider two new approaches to nonparametric estimation of the leverage effect. The first approach uses stock prices alone. The second approach uses the data on stock prices as well as a certain volatility instrument, such as the CBOE volatility index (VIX) or the Black-Scholes implied volatility. The theoretical justification for the instrument-based estimator relies on a certain invariance property, which can be exploited when high frequency data is available. The price-only estimator is more robust since it is valid under weaker assumptions. However, in the presence of a valid volatility instrument, the price-only estimator is inefficient as the instrument-based estimator has a faster rate of convergence. We consider two empirical applications, in which we study the relationship between the leverage effect and the debt-to-equity ratio, credit risk, and illiquidity.
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A new method for enhancing the 2.1 VSWR impedance bandwidth of microstrip antennas is presented. Bandwidth enhancement is achieved by loading the microstrip antenna by a ceramic microwave dielectric resonator (DR). The validity of this technique has been established using rectangular and circular radiating geometries. This method improves the bandwidth of a rectangular microstrip antenna to more than 10% (= 5 times that of a conventional rectangular microstrip antenna) with an enhanced gain of I dB
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School of management studies
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El artículo describe las características centrales de la reforma regulatoria al sector eléctrico en 1994 y evalúa el desempeño y la eficiencia de las empresas públicas antes y después de la reforma. El análisis de desempeño evalúa los cambios en medias y medianas en ganancias, eficiencia, inversión y ventas de las empresas privatizadas en el sector. La eficiencia técnica es estimada mediante la técnica DEA en una muestra de 33 plantas térmicas de energía, que representan el 85% del parque térmico; y 12 empresas distribuidoras de energía. La muestra de plantas generadoras está compuesta por plantas que estaban activas antes de la reforma y plantas nuevas que entraron en operación después de la reforma. Los principales resultados muestran que la eficiencia mejoro después de la reforma y que la política regulatoria ha tenido un efecto positivo en la eficiencia de la generación térmica de energía. Por el contrario, las distribuidoras de energía menos eficientes empeoraron después de la reforma y no llevaron a cabo una reestructuración para alcanzar la eficiencia productiva respecto a las empresas que conforman la frontera de eficiencia en distribución de energía.
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We study the role of natural resource windfalls in explaining the efficiency of public expenditures. Using a rich dataset of expenditures and public good provision for 1,836 municipalities in Peru for period 2001-2010, we estimate a non-monotonic relationship between the efficiency of public good provision and the level of natural resource transfers. Local governments that were extremely favored by the boom of mineral prices were more efficient in using fiscal windfalls whereas those benefited with modest transfers were more inefficient. These results can be explained by the increase in political competition associated with the boom. However, the fact that increases in efficiency were related to reductions in public good provision casts doubts about the beneficial effects of political competition in promoting efficiency.