12,080 research outputs found

    Quantile Correlations: Uncovering temporal dependencies in financial time series

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    We conduct an empirical study using the quantile-based correlation function to uncover the temporal dependencies in financial time series. The study uses intraday data for the S\&P 500 stocks from the New York Stock Exchange. After establishing an empirical overview we compare the quantile-based correlation function to stochastic processes from the GARCH family and find striking differences. This motivates us to propose the quantile-based correlation function as a powerful tool to assess the agreements between stochastic processes and empirical data

    Three in one-multiple faunal elements within an endangered european butterfly species

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    Ice ages within Europe forced many species to retreat to refugia, of which three major biogeographic basic types can be distinguished: "Mediterranean", "Continental" and "Alpine / Arctic" species. However, this classification often fails to explain the complex phylogeography of European species with a wide range of latitudinal and altitudinal distribution. Hence, we tested for the possibility that all three mentioned faunal elements are represented within one species. Our data was obtained by scoring 1,307 Euphydryas aurinia individuals (46 European locations) for 17 allozyme loci, and sequencing a subset of 492 individuals (21 sites) for a 626 base pairs COI fragment. Genetic diversity indices, F statistics, hierarchical analyses of molecular variance, individual-based clustering, and networks were used to explore the phylogeographic patterns. The COI fragment represented 18 haplotypes showing a strong geographic structure. All but one allozyme loci analysed were polymorphic with a mean F-ST of 0.20, supporting a pronounced among population structure. Interpretation of both genetic marker systems, using several analytical tools, calls for the recognition of twelve genetic groups. These analyses consistently distinguished different groups in Iberia (2), Italy, Provence, Alps (3), Slovenia, Carpathian Basin, the lowlands of West and Central Europe as well as Estonia, often with considerable additional substructures. The genetic data strongly support the hypothesis that E. aurinia survived the last glaciation in Mediterranean, extra-Mediterranean and perialpine refugia. It is thus a rare example of a model organism that combines attributes of faunal elements from all three of these sources. The observed differences between allozymes and mtDNA most likely result from recent introgression of mtDNA into nuclear allozyme groups. Our results indicate discrepancies with the morphologically-based subspecies models, underlining the need to revise the current taxonomy.Estonian targeted financing project [Sf0180122s08]; DFG graduate school [1319]; [Pest-C/MAR/LA0015/2011]info:eu-repo/semantics/publishedVersio

    Direct medical costs of type 2 diabetes and its complications in Switzerland

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    Background: This paper analyses the direct medical costs of type 2 diabetes and its complications in Switzerland. Methods: Individual healthcare resource consumption related to type 2 diabetes and its complications was determined retrospectively in 1479 non-incident and non-dying patients over 12 months (1998-1999). Literature-derived attributable risks were used to correct for non-diabetes related macrovascular disease. Results: A total of 111 primary care physicians from 19 cantons throughout Switzerland participated. Their diabetic patients on average had 10.3 consultations per year related to this disease (95% CI: 10.0-10.7). Patients spent on average 2.7 days (95% CI: 2.2-3.3) per year in hospital due to diabetes and diabetes-related complications. Mean annual type 2 diabetes-related direct medical costs per patient amounted to CHF 3,508 / € 2,323 (95% CI: CHF 3,140-3,876 / € 2,080-2,567). They were particularly high in patients with insulin treatment or with complications. After application of attributable risks and a correction for the use of adjuvant materials, costs were CHF 3,324 / € 2,201. Assuming 250,000 patients with type 2 diabetes in Switzerland leads to an estimate of CHF 0.88 billion spent for this disease and its complications in 1998. This represents a share of about 2.2% of the country's total healthcare expenditures. Conclusion: These findings demonstrate the high economic importance of type 2 diabetes and its complications in Switzerlan

    Cerebral differences in explicit and implicit emotional processing - An fMRI study

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    The processing of emotional facial expression is a major part of social communication and understanding. In addition to explicit processing, facial expressions are also processed rapidly and automatically in the absence of explicit awareness. We investigated 12 healthy subjects by presenting them with an implicit and explicit emotional paradigm. The subjects reacted significantly faster in implicit than in explicit trials but did not differ in their error ratio. For the implicit condition increased signals were observed in particular in the thalami, the hippocampi, the frontal inferior gyri and the right middle temporal region. The analysis of the explicit condition showed increased blood-oxygen-level-dependent signals especially in the caudate nucleus, the cingulum and the right prefrontal cortex. The direct comparison of these 2 different processes revealed increased activity for explicit trials in the inferior, superior and middle frontal gyri, the middle cingulum and left parietal regions. Additional signal increases were detected in occipital regions, the cerebellum, and the right angular and lingual gyrus. Our data partially confirm the hypothesis of different neural substrates for the processing of implicit and explicit emotional stimuli. Copyright (c) 2007 S. Karger AG, Basel

    Dynamics of excited-state proton transfer systems via time-resolved photoelectron spectroscopy

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    The use of time-resolved photoelectron spectroscopy for analyzing excited state intramolecular proton transfer (ESIPT) and internal conversion dynamics in a model system was investigated. The photoelectron spectra of both the excited state enol and keto tautomers were presented as a function of pump laser wavelength and pump-probe time delay. It was found that the internal conversion dynamics in o-hydroxybenzaldehyde (OHBA) was influenced by interactions with a close-lying n??* state.open958
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