Maximum approximate entropy and r threshold: A new approach for regularity changes detection

Approximate entropy (ApEn) has been widely used as an estimator of regularity in many scientific fields. It has proved to be a useful tool because of its ability to distinguish different system's dynamics when there is only available short-length noisy data. Incorrect parameter selection (embedding dimension $m$, threshold $r$ and data length $N$) and the presence of noise in the signal can undermine the ApEn discrimination capacity. In this work we show that $r_{max}$ ($ApEn(m,r_{max},N)=ApEn_{max}$) can also be used as a feature to discern between dynamics. Moreover, the combined use of $ApEn_{max}$ and $r_{max}$ allows a better discrimination capacity to be accomplished, even in the presence of noise. We conducted our studies using real physiological time series and simulated signals corresponding to both low- and high-dimensional systems. When $ApEn_{max}$ is incapable of discerning between different dynamics because of the noise presence, our results suggest that $r_{max}$ provides additional information that can be useful for classification purposes. Based on cross-validation tests, we conclude that, for short length noisy signals, the joint use of $ApEn_{max}$ and $r_{max}$ can significantly decrease the misclassification rate of a linear classifier in comparison with their isolated use

Rubio de Francia's extrapolation theory: estimates for the distribution function

Let $T$ be an arbitrary operator bounded from $L^{p_0}(w)$ into $L^{p_0, \infty}(w)$ for every weight $w$ in the Muckenhoupt class $A_{p_0}$. It is proved in this article that the distribution function of $Tf$ with respect to any weight $u$ can be essentially majorized by the distribution function of $Mf$ with respect to $u$ (plus an integral term easy to control). As a consequence, well-known extrapolation results, including results in a multilinear setting, can be obtained with very simple proofs. New applications in extrapolation for two-weight problems and estimates on rearrangement invariant spaces are established too.Comment: 29 page

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

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]

Superficial characteristics of titanium after treatment of chorreated surface, passive acid, and decontamination with argon plasma

Background. Titanium is characterized by its biocompatibility, resistance to maximum stress, and fatigue and non-toxicity. The composition, surface structure, and roughness of titanium have a key and direct influence on the osseointegration processes when it is used in the form of dental implants. The objective of the present study is to characterize, at chemical, superficial, and biological levels, the result of the application of the sandblasted with large-grit and acid-etched (SLA) treatment consisting of coarse-grained and double-passivated acid blasting with subsequent decontamination with argon plasma on the surface of titanium implants type IV. (2) Methods. Four Oxtein® dental implants (Zaragoza, Spain) were investigated with the following coding: Code L63713T (titanium grade IV, 3.75 mm in diameter, and 13 mm in length). The surface of the implants was SLA type obtained from coarse-grained, double passivated acid, and decontaminated with argon plasma. The samples were in their sealed packages and were opened in our laboratory. The X-ray photoelectron spectroscopy (XPS) technique was used to characterize the chemical composition of the surface, and the scanning electronic microscope (SEM) technique was used to perform topographic surface evaluation. Cell cultures were also performed on both surfaces. (3) Results. The superficial chemical analysis of the studied samples presented the following components, approximately, expressed in atomic percentage: O: 39%; Ti: 18%; C: 39%; N: 2%; and Si: 1%. In the same way, the topographic analysis values were obtained in the evaluated roughness parameters: Ra: 1.5 μm ± 0.02%; Rq: 1.31 μm ± 0.33; Rz: 8.98 μm ± 0.73; Rp: 5.12 μm ± 0.48; Rv: 3.76 μm ± 0.51; and Rc: 4.92 μm ± 0.24. At a biological level, the expression of osteocalcin was higher (p < 0.05) on the micro-rough surface compared to that machined at 48 and 96 h of culture. (4) Conclusions. The data obtained in our study indicate that the total carbon content, the relative concentration of titanium, and the roughness of the treatment performed on the implants are in agreement with those found in the literature. Further, the roughness of the treatment performed on the implants throws a spongy, three-dimensional surface suitable for bone growth on it. The biological results found are compatible with the clinical use of the surface tested

Quality assessment by region in spot images fused by means dual-tree complex wavelet transform

This work is motivated in providing and evaluating a fusion algorithm of remotely sensed images, i.e. the fusion of a high spatial resolution panchromatic image with a multi-spectral image (also known as pansharpening) using the dual-tree complex wavelet transform (DT-CWT), an effective approach for conducting an analytic and oversampled wavelet transform to reduce aliasing, and in turn reduce shift dependence of the wavelet transform. The proposed scheme includes the definition of a model to establish how information will be extracted from the PAN band and how that information will be injected into the MS bands with low spatial resolution. The approach was applied to Spot 5 images where there are bands falling outside PAN’s spectrum. We propose an optional step in the quality evaluation protocol, which is to study the quality of the merger by regions, where each region represents a specific feature of the image. The results show that DT-CWT based approach offers good spatial quality while retaining the spectral information of original images, case SPOT 5. The additional step facilitates the identification of the most affected regions by the fusion process

Superficial characteristics of titanium after treatment of chorreated surface, passive acid, and decontamination with argon plasma

Background. Titanium is characterized by its biocompatibility, resistance to maximum stress, and fatigue and non-toxicity. The composition, surface structure, and roughness of titanium have a key and direct influence on the osseointegration processes when it is used in the form of dental implants. The objective of the present study is to characterize, at chemical, superficial, and biological levels, the result of the application of the sandblasted with large-grit and acid-etched (SLA) treatment consisting of coarse-grained and double-passivated acid blasting with subsequent decontamination with argon plasma on the surface of titanium implants type IV. (2) Methods. Four Oxtein® dental implants (Zaragoza, Spain) were investigated with the following coding: Code L63713T (titanium grade IV, 3.75 mm in diameter, and 13 mm in length). The surface of the implants was SLA type obtained from coarse-grained, double passivated acid, and decontaminated with argon plasma. The samples were in their sealed packages and were opened in our laboratory. The X-ray photoelectron spectroscopy (XPS) technique was used to characterize the chemical composition of the surface, and the scanning electronic microscope (SEM) technique was used to perform topographic surface evaluation. Cell cultures were also performed on both surfaces. (3) Results. The superficial chemical analysis of the studied samples presented the following components, approximately, expressed in atomic percentage: O: 39%; Ti: 18%; C: 39%; N: 2%; and Si: 1%. In the same way, the topographic analysis values were obtained in the evaluated roughness parameters: Ra: 1.5 μm ± 0.02%; Rq: 1.31 μm ± 0.33; Rz: 8.98 μm ± 0.73; Rp: 5.12 μm ± 0.48; Rv: 3.76 μm ± 0.51; and Rc: 4.92 μm ± 0.24. At a biological level, the expression of osteocalcin was higher (p < 0.05) on the micro-rough surface compared to that machined at 48 and 96 h of culture. (4) Conclusions. The data obtained in our study indicate that the total carbon content, the relative concentration of titanium, and the roughness of the treatment performed on the implants are in agreement with those found in the literature. Further, the roughness of the treatment performed on the implants throws a spongy, three-dimensional surface suitable for bone growth on it. The biological results found are compatible with the clinical use of the surface tested

The credibility of the Venezuela crawling-band system

This paper studies the credibility of the Venezuela crawling-band exchange rate regime during the period July, 1996-February, 2002. We show that, introducing some modifications, the credibility analysis widely applied to target zone regimes can also be used in studying the credibility of crawling- band regimes. In analyzing the credibility of the Venezuela crawling band, first we use the so-called simple credibility tests developed by Svensson (1991). Additionally, we estimate the expected rate of realignment using the drift- adjustment method. Both the credibility tests and the drift-adjustment method give similar results, showing that the crawling-band system was highly credible during the period.crawling band exchange rate system, credibility, realignments

Análisis del artículo 207-2 del estatuto tributario nacional el cual creó nuevas rentas exentas y su incidencia en las finanzas del estado

La inquietud por saber si el estado está cumpliendo los objetivos en sus finanzas, otorgando beneficios tributarios a diferentes sectores de la economía, tales como el sector hotelero, el sector agrícola primario, el sector energético, entre otros, a generado inquietud para analizar el articulo 207-2 de Estatuto Tributario Nacional, el cual creo nuevas rentas exentas desde el año 2002 con la expedición de la ley 788 de 2002. El objetivo es determinar si dichas exenciones en el impuesto sobre la renta y complementarios, compensan dentro del Presupuesto General de la Nación, los ingresos que deja de percibir el Estado al otorgar dichos beneficios tributariosThe restlessness to know if the State is fulfilling the objectives in its finances, granting tributary benefits to different sectors from the economy, such as the hotel sector, the primary sector agricultural, the power sector, among others, to generated restlessness to analyze article 207-2 of National Statute Tributary, which I create new rents free from year 2002 with the expedition of 2002 law 788. The objective is to determine if these exemptions in the tax on the rent and complementary, compensate within the General Budget of the Nation, the income that stop perceiving the State when granting these tributary benefit

Job-search strategies of individuals at risk of poverty and social exclusion in Spain

In Spain, the issue of unemployment or precarious employment worsen with globalization, leading to an expansion of the so-called working poor in the labour market.According to previous literature, the economic poverty that is characteristic of this group may accompany poverty competency.In particular, the working poor resort to informal and poorly developed job-searchstrategies.This study addresses the job search methods used by people at risk of poverty and social exclusion. It provides evidence on the subject and serves as a basis for the adaptation of socio-labour intermediation programmes to this group.The hypothesis of this study is that people at high risk will predominantly use informal strategies that require a low level of job-searchs kills.A survey-based correlational study is conducted using a questionnaire completed by 279 people participating in socio-labourinter mediation programmes developed by the Action against Hunger Foundation(AaHF) in Spain.Information on poverty indicators and on job-search strategies is collected.Data are analysed through cluster analysis,which distinguish two groups of people at risk of poverty and social exclusion(high risk and low risk),followed by a comparison of means(t-test)with a subsequent calculation of effect size using Cohen’s d. Results show statistically significant differences with a medium effect size(between 0.45 and 0.50)for the typology of job-search strategies used,confirming the initial hypothesis.These results offer relevant information that should be considered when developing programmes aimed at improving social and labour issues for people at risk of poverty and social exclusion.Ministry of Economy and Competitiveness (MINECO- Government of Spain)European Regional Development Fund (ERDF-FEDER