1,415 research outputs found

    History of geology: scottish uniformitarianism from the point of view of philosophy of science. Didactic implications

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    En este trabajo tratamos de hacer una aproximación a la Historia y Filosofía de la Geología mediante la aplicación del concepto de tradiciones de investigación de L. Laudan al nacimiento de la geología como ciencia con la “Teoría de La Tierra” de J. Hutton y los “Principios de Geología” de C. Lyell, que sentaron las bases del uniformismo/actualismo hegemónico desde 1840 hasta los años 60 del siglo pasado con la aparición del neocatastrofismo. Así mismo, veremos cómo estos conceptos se pueden aplicar en La Formación del Profesorado y en el currículo de ciencias del Bachillerato.We are trying in this work to do an approximation to History and Philosophy of Geology by the application of the concept of “research traditions” from L. Laudan to the birth of geology as science with the “Theory of the Earth” by J. Hutton and the “Principles of Geology” by C. Lyell, which founded the uniformitarianism/actualism, hegemonic theory from 1840 to the sixties of the last century, with the appearance of neocatastrofism. Also, we will see how these concepts can be applied to teacher treaning and the curriculum of sciences of post-compulsory secondary education

    Historical financial analogies of the current crisis

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    This paper tries to shed light on the historical analogies of the current crisis. To that end we compare the current sample distribution of Dow Jones Industrial Average Index returns for a 769-day period (from 15 September 2008, the Lehman Brothers bankruptcy, to September 2011), with all historical sample distributions of returns computed with a moving window of 769 days in the 2 January 1900 to 12 September 2008 period. Using a Kolmogorov-Smirnov and a x2 homogeneity tests which have the null hypothesis of equal distribution we find that the stock market returns distribution during the current crisis would be similar to several past periods of severe financial crises that evolved into intense recessions, being the sub-sample from 28 May 1935 to 17 Jun 1938 the most analogous episode to the current situation. Furthermore, when applying the procedure proposed by Diebold, Gunther and Tay (1998) for comparing densities of sub-samples, we obtain additional support for our findings and discover a period from 10 September 1930 to 13 October 1933 where the severity of the crisis overcomes the current situation having sharper tail events. Finally, when comparing historical market risk with the current risk, we observe that the current market risk has only been exceeded at the beginning of the Great Depression.Financial crisis, Great Recession, Great Depression

    Volatility transmission between stock and exchange-rate markets: A connectedness analysis

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    This paper empirically investigates volatility transmission among stock and foreign exchange markets in seven major world economies during the period July 1988 to January 2015. To this end, we first perform a static and dynamic analysis to measure the total volatility connectedness in the entire period (the system-wide approach) using a framework recently proposed by Diebold and Yilmaz (2014). Second, we make use of a dynamic analysis to evaluate the net directional connectedness for each market. To gain further insights, we examine the time-varying behaviour of net pair-wise directional connectedness during the financial turmoil periods experienced in the sample period Our results suggest that slightly more than half of the total variance of the forecast errors is explained by shocks across markets rather than by idiosyncratic shocks. Furthermore, we find that volatility connectedness varies over time, with a surge during periods of increasing economic and financial instability

    Calcified Nodule Mimicking Red Thrombus on Optical Coherence Tomography

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    Functional Renormalization Group flows on Friedman-Lema\^{\i}tre-Robertson-Walker backgrounds

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    We reanalyze the construction of the gravitational functional renormalization group equation tailored to the Arnowitt-Deser-Misner formulation emphasizing its connection to the covariant formulation. The results obtained from projecting the renormalization group flow onto the Einstein-Hilbert action are reviewed in detail and we provide a novel example illustrating how the formalism may be connected to the Causal Dynamical Triangulations approach to quantum gravity.Comment: 14 pages, 2 figure

    Greenland sharks (Somniosus microcephalus) Spanish data (Surveys and Fishery) in NAFO Regulatory Area.

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    The aim of this paper is to update the Spanish commercial and survey catches for the Greenland sharks (Somniosus microcephalus) presented González-Costas and Ramilo (2017). An analysis of the 2018 catches estimated by the Scientific Observers and NAFO Observers is also presented

    Greenland sharks (Somniosus microcephalus) Spanish data (Surveys and Fishery) in NAFO Regulatory Area

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    The analysis of EU NAFO Regulatory Area surveys and Spanish Scientific Observers fishery data from Divisions 3LMNO show that Greenland sharks is not abundant and that this species appears in these Divisions sporadically and in depths of more than 300 meters. The surveys depth information is slightly different from that collected by scientific observers where most of the catches are at depths greater than 700 meters. Based on the Scientific Observers show that most of the catches of this species are mainly a by catch of the Greenland halibut fishery.Versión del edito

    Depth Distribution of the Effort, CPUE, Proportion of Mature and Oversized in the Catches of the Spanish Fisheries in NAFO Area

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    This paper reports an analysis of the depth distribution of effort and CPUE of the Spanish fleet, as well as undersized fish proportions and mature rates in the Spanish catches of five different species (Greenland halibut, American plaice, cod, yellowtail flounder, skate). Data were collected by the Spanish scientific observer program in the areas NAFO Div. 3LMNO during the period 1996-2000. More than 80% of the annual effort is carried out in the strata of 600-800, 800-1000 and >1000 meters. The species with highest yields in these strata is the Greenland halibut. 10% of the effort is carried out in the stratum of <200 meters and within this the highest yields correspond to skate and American plaice. The proportion of mature fish in the catches depends on depth for Greenland halibut and skate, whilst for the rest of the species the proportions of mature fish are bigger and more stable. The percentage of oversized fish is quite high, bigger than 95% in all species and ranges of depth

    New records and distribution extensions of centrolenid frogs for Venezuela

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    We report the first record of Centrolene notostictum for Venezuela, the first records of Centrolene venezuelense and Hyalinobatrachium pallidum for Zulia state, and extend the distribution of Hyalinobatrachium tatayoi and Espadarana andina based on specimens coming from the eastern versant of the Sierra de Perijá in northwestern Venezuela. The altitudinal ranges of all species are extended, and comments and notes on natural history provided
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