A POWERFUL TEST FOR CONDITIONAL HETEROSCEDASTICITY FOR FINANCIAL TIME SERIES WITH HIGHLY PERSISTENT VOLATILITIES.

Traditional tests for conditional heteroscedasticity are based on testing for significant autocorrelations of squared or absolute observations. In the context of high frequency time series of financial returns, these autocorrelations are often positive and very persistent, although their magnitude is usually very small. Moreover, the sample autocorrelations are severely biased towards zero, specially if the volatility is highly persistent. Consequently, the power of the traditional tests is often very low. In this paper, we propose a new test that takes into account not only the magnitude of the sample autocorrelations but also possible patterns among them. This aditional information makes the test more powerful in situations of empirical interest. The asymptotic distribution of the new statistic is derived and its finite sample properties are analized by means of Monte Carlo experiments. The performance of the new test is compared with other alternative tests. Finally, we illustrate the results analysing several real time series of financial returns.

Preliminary report on estimating potassium content of soils and minerals

Agradecemos a la Fundación Juan March la ayuda prestada para realizar este trabajo.The potassium contens in clay minerals has been estimated by the Cluley´s method.On stablish the relation between the % of K and the K-40 radio-activity for different densitys.This reation has been also used to determine the total amount of K in soils of England (JULIO RODRIGUEZ, G.E.G. Mattingly y O. Talibudeen; paper sended to Journal of Science of Food and Agriculture.I am indebted to Dr. G. E. G. Mattingly and Dr. O. Talibudeen for their assistance.En el presente trabajo se determina el contenido en potasio en varios minerales de la arcilla (moscovita,glauconita y bentonita - K) siguiendo el método de H. J. Cluley.A partir de esos valores se establece una relación entre el contenido en potasio y la radioactividad correspondiente al K-40 en función de la densidad.Esa relación nos ha permitido determinar radiométricamente el contenido en K en diversos suelos de Inglaterra (Trabajo en prensa J. RODRIGUEZ. G. E. G. Mattingly y O. Talibudeen. Rothamsted Experimental Station, Harprenden. Inglalerra).ROTHAMSTED EXPT. STATIO

Creatividad en el Arte: Descentramientos, aplicaciones, conexiones, complejidad

Se consideran algunas de las transformaciones ocurridas en el ámbito del arte en los últimos años, extrayendo sus rasgos fundamentales. A partir de ahí, se revisa la perspectiva tradicional sobre la creatividad artística y se ofrecen algunas claves, para considerar la creatividad en artes, ajustada a las nuevas manifestaciones artísticas, con la referencia en la complejidad y la interconexión

Creatividad, arte, artista, locura: una red de conceptos limítrofes.

El tema de la relación entre el artista o los individuos creadores y la locura ha sido siempre polémico y continúa siéndolo. A pesar de la abundante investigación, no parece que se haya llegado a ninguna solución definitiva acerca del carácter real o mitico de esa vinculación. Una vía de análisis que aquí se plantea, diferente a las habituales, puede ser el estudio de algunos de los conceptos implicados --arte, artista, creatividad, locura-- y de sus posibles puntos de contacto. Quizás esta perspectiva pueda facilitar una mayor comprensión del problema y de sus numerosas denvaciones.The topic of the relationship between artist or creative people and madness has always been polemie and it is so still. Despite a vast range of research, there seems to be no definitive answer to the discussion about the mythical or real character of this linldng. Another perspective to research, difi'erent from usual ones, can be to study several coneepts involved --art, artist, creativity, madness-- and the meetting arcas between them. Perhaps, this approach may help to understand the problem and bis several derivations

Are Seafarers Protected?

[Resumo] Que o mar é un xerador de riqueza é algo que ninguén dúbida: foino no pasado, éo no presente e serao, probablemente aínda máis, no futuro. E para afirmar que Europa é un continente marítimo, abonda o seguinte dato: «o 90% do comercio exterior da Unión Europea e máis do 40% do seu comercio interior efectúase por mar» (Comisión Europea, 2006). Neste contexto Galicia é líder en xente de mar: pesca e transporte marítimo. Conta cunha das sete escolas técnicas superiores de Náutica e Máquinas que existen en España. O 23 de outubro de 1549 o Concello da Coruña, por orde do rei Filipe II, acordou crear unha Cátedra de Gramática e Estudos do Mar. Desde entón, esta cidade formou oficiais da mariña mercante de recoñecido prestixio no mundo marítimo. Por outra banda, Galicia achega máis da metade do emprego pesqueiro de España e un 10% do conxunto da Unión Europea (UE). Con case 6000 embarcacións –pesca máis acuicultura–, a frota pesqueira galega supón o 48% do total nacional en 2013. Canto á súa dependencia social, poden resaltarse vilas como Bueu ou Ribeira, onde o emprego pesqueiro representa o 30% da poboación ocupada, que chega a valores do 60% na Illa de Arousa. Ora ben, os traballadores do mar non gozan dos mesmos niveis de protección que os do resto de actividades no tocante ás relacións laborais. O efecto máis inmediato disto é a falta de man de obra cualificada; e o seu efecto máis pernicioso, a perda de saúde dos traballadores. Como veremos ao longo deste traballo, a xente de mar desenvolve a súa xornada nunhas condicións realmente moi difíciles, nun medio inhóspito, agresivo ás veces. Unha mellora nas condicións laborais faría, sen dúbida, máis seguro e máis atractivo o traballo no mar, preocupacións ambas tanto das Nacións Unidas como da UE. Co obxectivo de abrir unha xanela, actualizada con data de 2013, a estas peculiares condicións de traballo que pola súa vez son condicións de vida, e facendo énfase no máis mellorable –lugares de traballo, ruído, enfermidades profesionais, vibracións, estatísticas, sinistralidade–, pomos ao día as distintas publicacións sobre o tema, case sempre acompañados por excelentes colegas investigadores. Todas elas tratan sobre a seguridade e a saúde laboral da xente de mar desde distintas perspectivas: profesional, xurídica, preventiva, científica...[Abstract] Nobody doubts that the sea is a source of wealth: it has been in the past, it is in the present and it will be, probably even more, in the future. Europe is a maritime continent: 90 % of European Union foreign trade and more than 40 % of its domestic trade is carried out by sea (European Commission, 2006). In this context Galicia is a leading region in sea workforce both in fishing and maritime transport sectors. One of the seven Spanish High Technical Colleges of Nautical Sciences and Marine Engineering is settled in Galicia. On October 23, 1549 La Corunna city council, by order of King Philip II, agreed to create a Chair of “Grammar and Sea Studies”. Since then, this city has educated and trained Merchant Marine Officers that are highly recognized in the maritime world. Also, Galicia provides more than a half of the Spanish fishing employment and 10 % of the European Union one. With almost 6,000 ships (devoted to fishing and aquiculture), the Galician fishing fleet is 48 % of the national fishing fleet (2013). With regard to its social value, Bueu and Ribeira are two examples of towns where fishing employment represents 30 % of the working population, coming to values of 60 % in Illa de Arousa town. But sea workers have not the same levels of occupational protection than the rest of working activities. The most immediate effect is the lack of skilled workforce; the most harmful one is the loss of workers’ health. We will see in this work that sea workers develop their working activities in very hard working conditions, in an inhospitable and sometimes aggressive environment. Improvements in these working conditions would undoubtedly make the work at sea safer and more attractive. These are both concerns of United Nations and European Union. With the purpose of reviewing the state of the art, this author shows the characteristic working and living conditions, emphasizing those improvable aspects (workplaces, noise, occupational diseases, vibrations, statistics and accident rates). In addition, several publications carried out on this topic are updated. All these publications are related to Occupational Safety and Health of sea workers from several perspectives such as the professional, juridical, preventionist and scientific ones

Noise on Board:Workers Protected?

[Resumo] Unha das moitas particularidades do traballo no mar, en concreto nos buques mercantes, é que os traballadores deben permanecer no centro de traballo, o buque, unha vez finalizada a xornada laboral. Non cabe dúbida da responsabilidade dos empresarios no tocante aos danos para a súa saúde que calquera traballador/a poida sufrir no seu traballo e durante a súa xornada laboral, mais até aí chega a súa responsabilidade, como sucede no resto de actividades laborais. Con todo, no mar, o buque non é só o lugar de traballo, tamén é a vivenda dos mariños, e podemos afirmar que as condicións de vida destes non son máis que unha continuación das súas condicións de traballo; ora ben, como debe considerarse un dano na saúde dos mariños nese intervalo de tempo non laboral que permanecen no centro de traballo, o buque? A xurisprudencia, por medio de numerosas sentenzas, estableceu o nexo causal entre o traballo dos mariños e o dano que poidan sufrir a bordo fóra da súa xornada laboral. Neste estudo tomouse o ruído como fío condutor da relación entre a responsabilidade dos empresarios e os danos que poden sufrir os traballadores non só na súa xornada laboral, senón tamén fóra dela. Mais que normativas sobre ruído se deben aplicar a ese período non laboral? Tecnicamente falando, trataríase de ruído laboral durante as oito horas da xeira e de ruído ambiental o resto da xornada, polo que entraría en escena non só a corresponsabilidade das autoridades (marítimas?, laborais?, de saúde pública?), senón tamén a normativa ambiental. Pola súa vez, o ámbito mundial do transporte marítimo trae consigo a aplicación de normativa internacional. No entanto, a pesar das variadas responsabilidades e das variadas normativas de aplicación, preguntámonos: fronte ao ruído a bordo, están os mariños protexidos?[Abstract] One of peculiarities of work at sea, in particular on merchant ships, is that the worker must remain at his workplace, on the ship, once his working shift has finalized. There is no doubt of the employers responsibility in regards to the health damages a worker can suffer in his job and during his working hours, but this is where his responsibilities end, as in other labour activities. However, at sea, the ship is not only the workplace, it is also the home of the marine and we can affirm that the conditions of life are not more than a continuation of his working conditions, but how ought we to considerer health damages to the marine in this interval of time, non-working hours, and who remains in the workplace, on the ship?. Jurisprudence, by means of numerous sentences, has established the causal link between the work of the marine and the damage, which he could suffer on board on his leisure time. In this study we adopt acoustic noise as a link between the responsibility of the employer and the damages that a worker may suffer, not only during his working shift, but also out of it. But what regulations must we apply to this during non-working periods?. Technically speaking, we refer to noise as that produced during the 8 hours of work and environmental noise during the rest of the day, by which the co-responsibilities of the authorities (maritime? labour? public health?) would enter into scene, as well as the environmental rules. In turn, the global stage of maritime transport brings about in its self the application of international rules. Nevertheless, in spite of the varied responsibilities and of the diverse rules of application, we ask ourselves in regards to the noise on board, is the marine protected

A methodology for population projections: an application to Spain

This paper looks at projections for the Spanish population by sex and age for the period of 2005 to 2050. These were carried out using forecasts for birth and mortality rates, and migration. These rates are calculated using two main sources of information. First, a multivariate time series model was applied for the series of variables from the 1970 to 2001 period. Second a model was estimated for life expectancy and for a synthetic fertility index. Both sources of information were combined to obtain the forecasts for the rates. Immigration rates are predicted by assuming three possible scenarios based on the maximum proportion that immigrants will represent in the Spanish population. With these variables a structure of ages and sex for the Spanish population is estimated using a cohort component model

Urbanismo, vivienda y economía en España

Peer Reviewe