Evaluating the role of energy efficiency labels in the prices of household appliances: the case of refrigerators

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Análisis de precios del mercado diario de electricidad español

El trabajo analiza los precios de la electricidad del mercado diario español. En el mismo se realiza un estudio del mercado eléctrico español y sus componentes junto con un análisis de los cambios regulatorios más significativos durante el periodo muestral. A partir de allí, se analiza la muestra a través de los estadísticos descriptivos principales. Luego se presenta un modelo general que es analizado a partir de los resultados empíricos principales obtenidos con su estimación. Finalmente, se realizan ajustes al mismo para obtener un modelo simplificado que se ajuste mejor a lo que se quiere conseguir, que es analizar la evolución de los precios de la electricidad. Los resultados del ajuste arrojan que los precios horarios dependen en su mayor parte de los precios de las horas anteriores. También que el modelo recoge muy bien la estacionalidad mensual y horaria que presenta la muestra. Por otro lado, características de la serie de precios como son la volatilidad y los saltos no quedan bien recogidos por el modelo, lo que lleva a plantearse la búsqueda de modelos alternativos.

Análisis de precios del mercado diario de electricidad español

El trabajo analiza los precios de la electricidad del mercado diario español. En el mismo se realiza un estudio del mercado eléctrico español y sus componentes junto con un análisis de los cambios regulatorios más significativos durante el periodo muestral. A partir de allí, se analiza la muestra a través de los estadísticos descriptivos principales. Luego se presenta un modelo general que es analizado a partir de los resultados empíricos principales obtenidos con su estimación. Finalmente, se realizan ajustes al mismo para obtener un modelo simplificado que se ajuste mejor a lo que se quiere conseguir, que es analizar la evolución de los precios de la electricidad. Los resultados del ajuste arrojan que los precios horarios dependen en su mayor parte de los precios de las horas anteriores. También que el modelo recoge muy bien la estacionalidad mensual y horaria que presenta la muestra. Por otro lado, características de la serie de precios como son la volatilidad y los saltos no quedan bien recogidos por el modelo, lo que lleva a plantearse la búsqueda de modelos alternativos.

Observations on the distribution, daytime migrations and daily food intake rates of Chaoborus flavicans (Meigen) in the Goggausee [Translation from: Carinthia II 165(85), 184-190, 1975]

The Goggausee, in spite of its modest depth (Zmax = 12 metres), shows meromictic properties: autumn and spring circulation extend only to a depth of 8 metres. The water layers below about 10 metres are constantly oxygen-free, the critical zone with at least intermittent oxygen loss lies at a depth of between 6 and 10 metres. A limnological excursion in May 1974 offered an opportunity to investigate the daily vertical migration of the species Chaoborus flavicans with reference to its food supply of zooplankton as well as the chance to carry out some preliminary experiments on its rate of food intake. Among the studied features were the planktonic depth distribution of Chaoborus flavicans and the food intake of Chaoborus larvae under experimental conditions.

Distribution of Healthcare resources II.Study and Comparison of a Linear Programming Problem and its Dual. Resolution and Evaluation of a Practical Case and its Programming using Excel and Win QSB.

[EN]This research had as primary objective to model different types of problems using linear programming and apply different methods so as to find an adequate solution to them. To achieve this objective, a linear programming problem and its dual were studied and compared. For that, linear programming techniques were provided and an introduction of the duality theory was given, analyzing the dual problem and the duality theorems. Then, a general economic interpretation was given and different optimal dual variables like shadow prices were studied through the next practical case: An aesthetic surgery hospital wanted to organize its monthly waiting list of four types of surgeries to maximize its daily income. To solve this practical case, we modelled the linear programming problem following the relationships between the primal problem and its dual. Additionally, we solved the dual problem graphically, and then we found the optimal solution of the practical case posed through its dual, following the different theorems of the duality theory. Moreover, how Complementary Slackness can help to solve linear programming problems was studied. To facilitate the solution Solver application of Excel and Win QSB programme were used.

Feeding ecology of Atlantic bluefin tuna (Thunnus thynnus) in North Carolina: diet, daily ration, and consumption of Atlantic menhaden (Brevoortia tyrannus)

Diet, gastric evacuation rates, daily ration, and population-level prey demand of bluefin tuna (Thunnus thynnus) were estimated in the continental shelf waters off North Carolina. Bluefin tuna stomachs were collected from commercial fishermen during the late fall and winter months of 2003–04, 2004–05, and 2005–06. Diel patterns in mean gut fullness values were used to estimate gastric evacuation rates. Daily ration determined from mean gut fullness values and gastric evacuation rates was used, along with bluefin tuna population size and residency times, to estimate population-level consumption by bluefin tuna on Atlantic menhaden (Brevoortia tyrannus). Bluefin tuna diet (n= 448) was dominated by Atlantic menhaden; other teleosts, portunid crabs, and squid were of mostly minor importance. The time required to empty the stomach after peak gut fullness was estimated to be ~20 hours. Daily ration estimates were approximately 2% of body weight per day. At current western Atlantic population levels, bluefin tuna predation on Atlantic menhaden is minimal compared to predation by other known predators and the numbers taken in commercial harvest. Bluefin tuna appear to occupy coastal waters in North Carolina during winter to prey upon Atlantic menhaden. Thus, changes in the Atlantic menhaden stock status or distribution would alter the winter foraging locations of bluefin

Recalculated diet and daily ration of the shortfin mako (Isurus oxyrinchus), with a focus on quantifying predation on bluefish (Pomatomus saltatrix) in the northwest Atlantic Ocean

The diet and daily ration of the shortfin mako (Isurus oxyrinchus) in the northwest Atlantic were re-examined to determine whether fluctuations in prey abundance and availability are reflected in these two biological variables. During the summers of 2001 and 2002, stomach content data were collected from fishing tournaments along the northeast coast of the United States. These data were quantified by using four diet indices and were compared to index calculations from historical diet data collected from 1972 through 1983. Bluefish (Pomatomus saltatrix) were the predominant prey in the 1972–83 and 2001–02 diets, accounting for 92.6% of the current diet by weight and 86.9% of the historical diet by volume. From the 2001– 02 diet data, daily ration was estimated and it indicated that shortfin makos must consume roughly 4.6% of their body weight per day to fulfill energetic demands. The daily energetic requirement was broken down by using a calculated energy content for the current diet of 4909 KJ/kg. Based on the proportional energy of bluefish in the diet by weight, an average shortfin mako consumes roughly 500 kg of bluefish per year off the northeast coast of the United States. The results are discussed in relation to the potential effect of intense shortfin mako predation on bluefish abundance in the region.

Age and growth of three species of Lake Victoria fish determined by means of otolith daily growth rings

The sagittal otoliths of Lates niloticus, Haplochromis obesus, and Oreochromis niloticus from Lake Victoria were examined for daily growth rings using scanning electron microscopy. In the three species the increments were clear and thick enough to allow future studies with light microscopy. The daily nature of the increments seems supported by the rhythmic growth that were found.

Diet composition and daily ration estimates of selected trawl-caught fishes in San Miguel Bay, Philippines

The diet composition of fish caught in San Miguel Bay, Philippines, in April and May 1993 was studied. The diets of tiger-tooth croaker (Otolithes ruber), commerson's anchovy (Stolephorus commersonii); and the Indian anchovy (Stolephorus indicus) consisted mainly of zooplankton, primarily crustaceans. The stomach content of orangefin ponyfish (Leiognathus bindus) was found to consist mostly of detritus and unidentified materials. Daily rations estimated were: 1.90 g day super(1) for O. ruber of 17.3 g mean body weight (BW), 0.078 g day super(1) for S. commersonii) of 3.8 g mean BW, 0.062 g day super(1) for S. indicus of 3.9 g mean BW and 0.56 g day super(1) for L. bindus of 7.7 g mean BW.

SUNLIGHT: a computer program for calculation of daily solar radiation

This paper presents an algorithm and software (available from ICLARM) for estimating the possible amount of sunlight that may fall on any location of the earth, any day of the year, as might be required for ecological modelling.