Acute Toxicity of Perfluorooctane Sulfonic Acid on Early Life Stages of Daphnia Magna, Siriella Armata, Paracentrotus Lividus Sea Urchin, and Turbot (Scophthalmus Maximus L.).

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant whose potential toxicity is causing great concern. In the present study, we used two crustaceans (_Daphnia magna_, _Siriella armata_), echinoid embryos (_Paracentrotus lividus_) and turbot (_Scophthalmus maximus L._) embryos and larvae to investigate the acute toxicity of this compound. The marine species _S. armata_ exhibited greater sensitivity than the freshwater species _D. magna_. In the 48-h acute toxicity test the median lethal concentration was 10.96 mg/L for _S. armata_ and 87.46 mg/L for _D. magna_. In the 96h toxicity test, turbot showed the lowest EC50 (0.155 mgL-1), whilst the EC50 for _S. armata_ was 7.92 mgL-1 which was approximately three times lower than that for sea urchin (24.12 mgL-1). The EC10 values were estimated as 0.032 mgL-1, 4.23 mgL-1 and 45.21 mgL-1 for turbot, Siriella and daphnia, respectively. The LOEC values were 75 µgL-1, 2.5 mgL-1 and 75 mgL-1 (p< 0.05) for turbot, daphnia, and Siriella, respectively. The NOEC values were estimated at 37.5 µgL-1, 1.25 mgL-1 and 50 mgL-1 (p< 0.05) for turbot, Siriella and daphnia, respectively. The order of acute toxicity was: turbot > _S. armata_ > sea urchin > _Daphnia magna_. This result highlights the importance of including a marine fish in the battery of species to describe the toxicity of these compounds. Considering the persistent nature of PFOS, more research is required to determine potential consequences of long-term exposure to these compounds in aquatic ecosystems

Estimación de la humedad de tapones de corcho mediante medida de la resistencia electrica

En este trabajo se exponen los resultados obtenidos en el Departamento de Productos Forestales del CIFOR-INIA sobre la relación entre la resistencia eléctrica y el contenido de humedad de los tapones de corcho. Estos resultados muestran que los medidores de humedad utilizados habitualmente en la industria pueden alcanzar una precisión elevada, siempre y cuando se tenga en cuenta la influencia de los distintos factores que afectan a la relación resistencia eléctrica-humedad: tipo de tapón, dirección de la medida, temperatura del material. Además, se han obtenido los modelos matemáticos que permiten la calibración de cualquier aparato de este tipo de manera rápida y sencill

Un altar de sacrificios humanos.

71 (3-4) Jul.-Dez. 1961, p. 375-390

Dos villas romanas de la Cibdá de Armea, en Santa Mariña de Águas Santas.

69 (3-4) Jul.-Dez. 1959, p. 472-500

Short-Term Price Forecasting Models Based on Artificial Neural Networks for Intraday Sessions in the Iberian Electricity Market

This paper presents novel intraday session models for price forecasts (ISMPF models) for hourly price forecasting in the six intraday sessions of the Iberian electricity market (MIBEL) and the analysis of mean absolute percentage errors (MAPEs) obtained with suitable combinations of their input variables in order to find the best ISMPF models. Comparisons of errors from different ISMPF models identified the most important variables for forecasting purposes. Similar analyses were applied to determine the best daily session models for price forecasts (DSMPF models) for the day-ahead price forecasting in the daily session of the MIBEL, considering as input variables extensive hourly time series records of recent prices, power demands and power generations in the previous day, forecasts of demand, wind power generation and weather for the day-ahead, and chronological variables. ISMPF models include the input variables of DSMPF models as well as the daily session prices and prices of preceding intraday sessions. The best ISMPF models achieved lower MAPEs for most of the intraday sessions compared to the error of the best DSMPF model; furthermore, such DSMPF error was very close to the lowest limit error for the daily session. The best ISMPF models can be useful for MIBEL agents of the electricity intraday market and the electric energy industry

Efecto de la temperatura de termotratamiento en el comportamiento eléctrico de la madera de pino radiata

Se analiza el efecto de la temperatura del termotratamiento sobre la conductividad eléctrica de la madera de pino radiata. Sobre probetas de madera de pino radiata de procedencia País Vasco (España), termotratada a 190ºC y 210ºC por el método Thermowood así como sobre piezas testigo de la misma especie, procedencia y dimensiones, acondicionadas todas ellas hasta masa constante a 20ºC/40%HR, 20ºC/65%HR y 20ºC/90%HR se evaluó la resistencia eléctrica (longitudinal y transversal) y, posteriormente, se ajustó el modelo Samuelson para modelizar en cada tipo de material la relación humedad de la madera-resistencia eléctrica. Se concluye que la temperatura empleada en el tratamiento térmico de la madera afecta no sólo a la humedad de equilibrio sino, también, a su conductividad eléctrica, siendo máximo este efecto en el tratamiento efectuado a 210ºC

Correlated Anisotropies in the Cosmic Far-Infrared Background Detected by MIPS/Spitzer: Constraint on the Bias

We report the detection of correlated anisotropies in the Cosmic Far-Infrared Background at 160 microns. We measure the power spectrum in the Spitzer/SWIRE Lockman Hole field. It reveals unambiguously a strong excess above cirrus and Poisson contributions, at spatial scales between 5 and 30 arcminutes, interpreted as the signature of infrared galaxy clustering. Using our model of infrared galaxy evolution we derive a linear bias b=1.74 \pm 0.16. It is a factor 2 higher than the bias measured for the local IRAS galaxies. Our model indicates that galaxies dominating the 160 microns correlated anisotropies are at z~1. This implies that infrared galaxies at high redshifts are biased tracers of mass, unlike in the local Universe.Comment: ApJ Letters, in pres

The influence of the moisture content on the electrical resistance of two types of cork stoppers

The relationship between the log of the electrical resistance (ER; measured using pin electrodes) and the moisture content (MC) have not been reported in any form of cork. That is important for the cork stoppers industry because it should help in the design and verification of more precise devices for measuring cork moisture content. In this study, using linear regression techniques, different regression models of the type log(Log(R) + 1) = axh + b were derived to describe the relationship ERMC, that was measured using pin electrodes on two types of cork stoppers [natural (N) and agglomerate(AG)]. The results obtained show that in the models proposed, the moisture content of AG cork stoppers can be estimated with an error of ± 0.3%, while that of N stoppers can be estimated with an error of 0.5%. Neither the geographical origin of the N corks nor the surface treatment to which the AG corks were subjected significantly affected the proposed models. Therefore, the moisture content of cork stoppers could be measured at the industrial scale using electrical resistancetype moisture meter

Noise influence on the Characteristic Relations and Reinjection Probability Densities of type-II and type-III Intermittencies

This paper explores the effect of the noise in the reinjection probability densities (RPD) for type-II and type-III intermittencies by using the temporal series of iterative maps. The RPD are calculated by means of a new method proposed in Refs. [1] and [2] and the results are compared with both, numerical simulations and analytical calculations. In addition, we provide an explanation for the gap observed in early experiments around the unstable point in the Poincaré map. We show that and added white noise approaches the RPD to the case of uniform reinjection for small distances of iterations to the unstable point. For large distances the RPD should be incremented with respect to the noiseless case. These numerical results suggest the existence of a noise induced reinjection mechanis

Os efeitos das perceções de instrumentalização da avaliação de desempenho nas respostas face à organização

Doutoramento em GestãoReconhecendo que os objetivos de rigor e exatidão na avaliação de desempenho são difíceis, se não mesmo impossíveis de alcançar, o presente trabalho pretende contribuir para o desenvolvimento dos estudos sobre os fatores contextuais, nomeadamente os comportamentos políticos dos avaliadores, que influenciam o processo de avaliação e as respostas dos colaboradores face à organização. Estudou-se os efeitos das perceções de instrumentalização da avaliação de desempenho nas respostas face à organização, considerando que estas dependem dos motivos subjacentes à instrumentalização percecionados pelos avaliados. Optou-se por uma metodologia mista, tendo-se realizado entrevistas e aplicado um inquérito por questionário a uma amostra de colaboradores de diversas entidades públicas e privadas. O estudo qualitativo possibilitou aprofundar o conhecimento sobre os antecedentes, motivações e consequências da instrumentalização. Mostrou que os entrevistados valorizam o rigor e isenção por parte dos avaliadores bem como reconhecem a importância do feedback e acompanhamento para apoiar o seu desenvolvimento profissional. O estudo quantitativo permitiu verificar que os avaliados distinguem a instrumentalização que visa servir os interesses do avaliador daquela que visa beneficiar os avaliados ou a organização. Constatou-se que as perceções de motivações egoístas estão positivamente relacionadas com a saída, a negligência e o cinismo organizacional e negativamente relacionadas com a lealdade. Verificou-se ainda que as perceções de comportamento ético do avaliador assumem um papel mediador nessa relação, eliminando o impacto da instrumentalização nas respostas face à organização. Os resultados dos estudos desenvolvidos sugerem que o julgamento dos avaliados sobre o comportamento dos seus avaliadores não se rege apenas pelo princípio da justiça mas também pelo princípio do bem-estar dos outros, pelo que, em futuras pesquisas sobre a avaliação de desempenho, será desejável investigar a coexistência desses dois princípios.Recognizing that performance appraisal accuracy is difficult, if not impossible to achieve, this thesis aims to contribute to the study of the contextual factors, namely the raters’ political behaviours, which influence the evaluation process and employees’ reactions towards the Organization. The effects of perceptions of performance appraisal instrumentalization on employees’ reactions were studied considering that these reactions vary according to the perceived underlying motives of the instrumentalization. A mixed method approach was adopted, comprised of interviews and a survey questionnaire conducted to a sample of employees of both public and private entities. The qualitative study allows a better understanding of the perceptions of the antecedents, motivations and outcomes of the instrumentalization. It shows that the interviewees value the accuracy and impartiality of their evaluators. Moreover, feedback and supervisor support conducive to personal development are also relevant. The quantitative study shows that the employees distinguish the instrumentalization motivated by the rater’s self-interest from the instrumentalization that aims to benefit the employees or the Organization. The perceptions of selfish motivations are positively related to exit, negligence and organizational cynicism and negatively related to loyalty. Further, it was found that the perceptions of rater’s ethical behaviour assume a mediating role in that relationship, eliminating the impact of the perceptions of performance appraisal instrumentalization on the employees’ reactions towards the Organization. The results of both studies suggest that employees’ judgment on the raters’ behaviour is not only governed by the principle of justice but also by the principle of welfare. Therefore, future research on performance appraisal should consider analysing the coexistence of those principles