Estudio sobre las relaciones entre la percepción de competencia, el estado de ánimo y la tolerancia al estrés en jóvenes deportistas en formación

247 p.

Análisis de la influencia de los sistemas de puesta a tierra en la eficiencia de instalaciones eléctricas de baja tensión residenciales e industriales.

[EN]Nowadays, global society is more aware of electrical energy’s risks than never before, and electrical safety has turned a priority when a new installation is designed. So, a great protection to an unwanted electric hazard is required, being specially careful with indirect contacts. If a circuit has an insulation failure and an indirect contact is produced, there is risk of an accidental electrocution, risk that must be avoided by making a good choice of the grounding methodology and properly coordinating the electrical protections in the installation. In order to minimize that risk, a study of low voltage industrial and residential installation’s grounding methodologies is introduced, analyzing the tree grounding methodologies internationally accepted (TT, TN, IT). In addition, two real examples are solved (using a computer-aided engineering software), confirming the results of the theoretical study.

Evaluation of marine phytoplankton toxicity by application of marine invertebrate bioassays

The dinoflagellate Alexandrium minutum and the haptophyte Prymnesium parvum are well known for their toxin production and negative effects in marine coastal environments. A. minutum produces toxins which cause paralytic shellfish poisoning in humans and can affect copepods, shellfish and other marine organisms. Toxins of P. parvum are associated with massive fish mortalities resulting in negative impacts on the marine ecosystem and large economic losses in commercial aquaculture. The aim of this work is to improve our knowledge about the reliability of the use of marine invertebrate bioassays to detect microalgae toxicity, by performing: (i) a 24- to 48-h test with the brine shrimp Artemia franciscana; (ii) a 48-hour embryo-larval toxicity test with the sea urchin Paracentrotus lividus; and (iii) a 72-h test with the amphipod Corophium multisetosum. The results indicate that A. franciscana and P. lividus larvae are sensitive to the toxicity of A. minutum and P. parvum. LC50 comparison analysis between the tested organisms reveals that A. franciscana is the most sensitive organism for A. minutum. These findings suggest that the use of different organizational biological level bioassays appears to be a suitable tool for A. minutum and P. parvum toxicity assessment.