25,982 research outputs found

    The Dual Stickiness Model and Inflation Dynamics in Spain

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    We estimate a model that integrates sticky prices and sticky information using Spanish data following Dupor et. al (2008). The model yields three empircal facts: a-) the frequency of price changes (around one year), b-) the firm's report that sticky information is no too important for nominal rigidities and c-) the inflation's persistence, the latter with more microfoundations than the Hybrid Model. We found that both types of stickiness are present in Spain, but the most important is the stickiness in prices.Sticky Prices; Sticky Information; Spain; Inflation Dynamics

    Revisiting the Classics to recover the Physical Sense in electrical noise

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    This paper shows a physically cogent model for electrical noise in resistors that has been obtained from Thermodynamical reasons. This new model derived from the works of Johnson and Nyquist also agrees with the Quantum model for noisy systems handled by Callen and Welton in 1951, thus unifying these two Physical viewpoints. This new model is a Complex or 2-D noise model based on an Admittance that considers both Fluctuation and Dissipation of electrical energy to excel the Real or 1-D model in use that only considers Dissipation. By the two orthogonal currents linked with a common voltage noise by an Admittance function, the new model is shown in frequency domain. Its use in time domain allows to see the pitfall behind a paradox of Statistical Mechanics about systems considered as energy-conserving and deterministic on the microscale that are dissipative and unpredictable on the macroscale and also shows how to use properly the Fluctuation-Dissipation Theorem

    Stretchable electronics for artificial skin

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    Postprint (published version

    Developing Allometric Equations for Teak Plantations Located in the Coastal Region of Ecuador from Terrestrial Laser Scanning Data

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    Traditional studies aimed at developing allometric models to estimate dry above-ground biomass (AGB) and other tree-level variables, such as tree stem commercial volume (TSCV) or tree stem volume (TSV), usually involves cutting down the trees. Although this method has low uncertainty, it is quite costly and inefficient since it requires a very time-consuming field work. In order to assist in data collection and processing, remote sensing is allowing the application of non-destructive sampling methods such as that based on terrestrial laser scanning (TLS). In this work, TLS-derived point clouds were used to digitally reconstruct the tree stem of a set of teak trees (Tectona grandis Linn. F.) from 58 circular reference plots of 18 m radius belonging to three different plantations located in the Coastal Region of Ecuador. After manually selecting the appropriate trees from the entire sample, semi-automatic data processing was performed to provide measurements of TSCV and TSV, together with estimates of AGB values at tree level. These observed values were used to develop allometric models, based on diameter at breast height (DBH), total tree height (h), or the metric DBH2 × h, by applying a robust regression method to remove likely outliers. Results showed that the developed allometric models performed reasonably well, especially those based on the metric DBH2 × h, providing low bias estimates and relative RMSE values of 21.60% and 16.41% for TSCV and TSV, respectively. Allometric models only based on tree height were derived from replacing DBH by h in the expression DBH2 x h, according to adjusted expressions depending on DBH classes (ranges of DBH). This finding can facilitate the obtaining of variables such as AGB (carbon stock) and commercial volume of wood over teak plantations in the Coastal Region of Ecuador from only knowing the tree height, constituting a promising method to address large-scale teak plantations monitoring from the canopy height models derived from digital aerial stereophotogrammetry

    Comments on : diet, physiology and ecology of fossil mammals as inferred from stable carbon and nitrogen isotope biogeochemistry: implications for Pleistocene bears

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    A detailed study of isotopic relationships in European Pleistocene ursid teeth have been presented by Bocherens et al. (1994). We agree with the resu1ts and broad conclusions derived from the stable carbon isotope relationships. These are findings that confirm the previous hypothesis relating to the diets of Ursus deningeri and Ursus spelaeu

    Pleistocene paleoenvironmental evolution at continental middle latitude inferred from carbon and oxygen stable isotope analysis of ostracodes from the Guadix-Baza Basin (Granada, SE Spain)

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    A representative paleoenvironmental reconstruction of continental middle latitude from ca. 2my to the upper part of Middle Pleistocene (279±77ky) was obtained from the carbon and oxygen stable isotopes analyzed in ostracode shells (Cyprideis torosa) recovered in the Guadix-Baza Basin (SE Spain), an intramontaneous closed depression filled by alluvial and lacustrine sediments. This study was performed along a 356-m-thick composite section, dated previously by paleomagnetism and the amino acid racemization method. 013C and 0180 profiles reflected changes in temperature, the evaporationJinfill ratio in the water bodies and the amount of rain. 013C is also affected by changes in plant biomass: periods with high 013C and 0180 values are associated with warm and dry regimes, and with less vegetation, which, in some cases, coincide with the development of displacive gypsum crystals, whereas low 013C and 0180 values correlate with cold and humid episodes, which cause more vegetation biomass and, therefore, increasing the input of isotopically light carbon. Intermediate 0180 values are linked to temperate dry or humid episodes when they coincide with high or low 013C values, respectively. 86 paleoclimatic events were distinguished in the Pleistocene record from the 013C and 0180 profiles. From both the statistical analysis of the geochemical data and the geological observations, four Cold and Humid Long Periods (low 0180) and four Warm and Dry Long Periods (high 0180) were defined. This differs with respect to the paleoclimatological behavior established for the Northern Hemisphere where during cold periods (glacial), no water was available while permafrost conditions persisted, whereas in warm episodes (interglacial), higher precipitation rates occurred. Good correspondences between the Guadix-Baza Basin paleoclimatic record and a marine oxygen-isotope sequence, two continental cores and other long Mediterranean paleoenvironmental records (pollen sequences from Israel) were found, which suggested that climate changes in the Guadix-Baza Basin were in tune with global climatic changes

    Scale and structure of time-averaging (age mixing) in terrestrial gastropod assemblages from Quaternary eolian deposits of the eastern Canary Islands

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    Quantitative estimates of time-averaging (age mixing) in gastropod shell accumulations from Quaternary (the late Pleistocene and Holocene) eolian deposits of Canary Islands were obtained by direct dating of individual gastropods obtained from exceptionally well-preserved dune and paleosol shell assemblages. A total of 203 shells of the gastropods Theba geminata and T. arinagae, representing 44 samples (= strati graphic horizons) from 14 sections, were dated using amino acid (isoleucine) epimerization ratios calibrated with 12 radiocarbon dates. Most samples reveal a substantial variation in shell age that exceeds the error that could be generated by dating imprecision, with the mean within-sample shell age range of 6670 years and the mean standard deviation of 2920 years. Even the most conservative approach (Monte Carlo simulations with a non-sequential Bonferroni correction) indicates that at least 25% of samples must have undergone substantial time-averaging (e.g., age variations within those samples cannot be explained by dating imprecision alone). Samples vary in shell age structure, including both left-skewed (17 out of 44) and right-skewed distributions (26 out of 44) as well as age distributions with a highly variable kurtosis. Dispersion and shape of age distributions of samples do not show any notable correlation with the stratigraphic age of samples, suggesting that the structure and scale of temporal mixing is time invariant. The statistically significant multi-millennial time-averaging observed here is consistent with previous studies of shell accumulations from various depositional settings and reinforces the importance of dating numerous specimens per horizon in geochrono logical studies. Unlike in the case of marine samples, typified by right-skewed age distributions (attributed to an exponential-like shell loss from older age classes), many of the samples analyzed here displayed leftskewed distributions, suggestive of different dynamics of age mixing in marine versus terrestrial shell accumulations

    Anomalies in the cognitive-executive functions in patients with chiari malformation type I

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    Resumen tomado de la publicaciónAnomalías en las funciones cognitivo-ejecutivas en pacientes con la Malformación de Chiari Tipo I. Antecedentes: en la última década, existen evidencias crecientes de que déficits neuropsicológicos, esencialmente en funciones ejecutivas, pueden estar involucrados en la patogenia de la enfermedad de Chiari Tipo I. El objetivo del estudio es evaluar la influencia de anormalidades estructurales sobre las funciones neuropsicológicas, fundamentalmente ejecutivas, en pacientes con Chiari Tipo I. Método: para ello se comparó el perfil neuropsicológico de estos pacientes con controles sanos. Tanto a los pacientes Chiari Tipo I como a los controles sanos se les aplicó pruebas neuropsicológicas que valoraron funciones ejecutivas frontales de vigilancia o atención sostenida, flexibilidad mental, y planificación y formación de conceptos (Stroop, CPT, WCST). Resultados: los resultados obtenidos sugieren una afectación de los pacientes Chiari Tipo I en los procesos de inhibición y autocontrol (Stroop) y en la capacidad atencional y en el mantenimiento del curso del pensamiento y la acción (WCST). Conclusiones: estos resultados proporcionan evidencias de posibles déficits o anomalías en las funciones ejecutivas cognitivas, que permitirían diferenciar los pacientes con Chiari Tipo I.Universidad de Oviedo. Biblioteca de Psicología; Plaza Feijoo, s/n.; 33003 Oviedo; Tel. +34985104146; Fax +34985104126; [email protected]

    Innovative Corporate Social Responsibility in Botswana: The Debswana Mining Company Study Case

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    This paper presents a study case on innovative corporate social responsibility as a very important aspect of management planning and, in the process, explores some trends and new ideas pertaining to corporate social responsibility in mining industries. Some pertinent literature is reviewed as a theoretical frame to introduce the presentation of the Debswana Mining Company case to show innovative corporate social responsibility in the mining industries in Botswana

    Particle production from marginally trapped surfaces of general spacetimes

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    We provide a general formalism that allows to analyze the phenomenon of tunneling in arbitrary spacetimes. We show that a flux of particles produced by tunneling through general marginally trapped surfaces may be perceived by some privileged observers. We discuss how this particle perception can be related to Hawking/Unruh radiation in specific cases. Our approach naturally leads to an expression for the effective surface gravity of marginally trapped surfaces. The procedure is applicable to general astrophysical and cosmological dynamical situations. Some practical examples for known and new cases are provided.Comment: 24 pages, 2 figures. Section 4.2, concerning the analysis of the Kerr-Vaidya solution, has been rewritten, correcting mistakes in previous versions. The corrected calculations do support our claims. A corrigendum has also been sent to CQG. New references added. Some of the mistakes in previous versions are actually common and spread in the literature on the Kerr-Vaidya solutio
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