Colour Changes of Acetal Resins (CAD-CAM) In Vivo

To quantify the discolouration of the temporary acetal resins in vivo, based on the weeks of follow-up and the salivary pH in the three thirds of the tooth. To find out if the final CIELAB coordinates can be predicted from the initial colour coordinates, the salivary pH, the situation (in thirds) and the weeks of follow-up. Colour coordinates (L, C, and h) were recorded by spectrophotometry in 13 participants fitted with hybrid provisional complete dentures made of acetal resin. Colour recordings were made on the day of placement and after several weeks of follow-up (6 to 31 weeks). Salivary pH was also measured as a predictor variable for colour change. The ANOVA statistical test and regression models have been used. The highest colour difference according to DEab* was 27.46 units after 15 weeks of follow-up and the lowest was 7.34 units after 17 weeks of follow-up. Neither in the cervical nor in the middle third any regressor variable (initial L*, initial C*, initial h*, salivary pH and weeks of follow-up) was able to significantly predict any of the final colour coordinates (p > 0.05). The colour change of the temporary acetal resins used exceeds the threshold of clinical acceptability, and it is not acceptable to maintain satisfactory aesthetics. The weeks of follow-up and the salivary pH are not capable of satisfactorily predicting the final color coordinates of the acetal resins

A Comparison of Front-Ends for Bitstream-Based ASR over IP

Automatic speech recognition (ASR) is called to play a relevant role in the provision of spoken interfaces for IP-based applications. However, as a consequence of the transit of the speech signal over these particular networks, ASR systems need to face two new challenges: the impoverishment of the speech quality due to the compression needed to fit the channel capacity and the inevitable occurrence of packet losses. In this framework, bitstream-based approaches that obtain the ASR feature vectors directly from the coded bitstream, avoiding the speech decoding process, have been proposed ([S.H. Choi, H.K. Kim, H.S. Lee, Speech recognition using quantized LSP parameters and their transformations in digital communications, Speech Commun. 30 (4) (2000) 223–233. A. Gallardo-Antolín, C. Pelàez-Moreno, F. Díaz-de-María, Recognizing GSM digital speech, IEEE Trans. Speech Audio Process., to appear. H.K. Kim, R.V. Cox, R.C. Rose, Performance improvement of a bitstream-based front-end for wireless speech recognition in adverse environments, IEEE Trans. Speech Audio Process. 10 (8) (2002) 591–604. C. Peláez-Moreno, A. Gallardo-Antolín, F. Díaz-de-María, Recognizing voice over IP networks: a robust front-end for speech recognition on the WWW, IEEE Trans. Multimedia 3(2) (2001) 209–218], among others) to improve the robustness of ASR systems. LSP (Line Spectral Pairs) are the preferred set of parameters for the description of the speech spectral envelope in most of the modern speech coders. Nevertheless, LSP have proved to be unsuitable for ASR, and they must be transformed into cepstrum-type parameters. In this paper we comparatively evaluate the robustness of the most significant LSP to cepstrum transformations in a simulated VoIP (voice over IP) environment which includes two of the most popular codecs used in that network (G.723.1 and G.729) and several network conditions. In particular, we compare ‘pseudocepstrum’ [H.K. Kim, S.H. Choi, H.S. Lee, On approximating Line Spectral Frequencies to LPC cepstral coefficients, IEEE Trans. Speech Audio Process. 8 (2) (2000) 195–199], an approximated but straightforward transformation of LSP into LP cepstral coefficients, with a more computationally demanding but exact one. Our results show that pseudocepstrum is preferable when network conditions are good or computational resources low, while the exact procedure is recommended when network conditions become more adverse.Publicad

La importancia de la segregación de itrio en la deformación plástica de nanocristales de circonia tetragonal dopada con óxido de itrio (YTZP)

Muestras de YTZP (policristales de oxido de circonio dopado con itria) con tamaño medio de grano de 50 nm, puras y con un 10% en peso de diferentes fases vítreas han sido deformadas a carga constante en un rango de temperatura comprendido entre 1150-1200 ºC. Con dicho estudio se pretende caracterizar el comportamiento mecánico del material y estudiar la influencia de la segregación de itria en la frontera de los granos en los posibles mecanismos de deformación. Igualmente se ha llevado a cabo un estudio microscópico con el fin de obtener una completa caracterización del material. Se han analizado micrografías de las muestras recibidas y de las deformadas a partir de Microscopía Electrónica de Transmisión convencional (TEM), y de las fronteras de granos de dichas muestras por Microscopía Electrónica de Transmisión de Alta Resolución (HRTEM). Se ha probado que la existencia de segregación catiónica hacia las fronteras de granos está relacionada con la falta de una tensión umbral. El parámetro n no se ve alterado por dicha segregación, en buen acuerdo con la ausencia de tensión umbral.Nano-sized YTZP (Yttria Tetragonal Zirconia Polycrystals) samples, pure and doped with 10 wt.% of different glassy phases have been crept in a range of temperature between 1150-1200 ºC. Macroscopic characterization of the mechanical behaviour of these material and a study on the effect of the grain boundaries yttria segregation on the mechanical response of these materials have been carried out. Moreover, a microstructural analysis by conventional Transmission Electron Microscopy (TEM) of both, as-received and deformed samples and a study of the grain boundaries by High Resolution Transmission Electron Microscopy are required to have a complete characterization of these materials. The yttrium segregation to grain boundary is related to the non existence of a threshold stress. The parameter n is not altered by this segregation and grain boundary sliding seems to be the deformation mechanism

Learning communities: what is the university volunteers' contribution?

En este trabajo se presentan las valoraciones de los y las estudiantes universitarios que han participado como voluntarios en centros constituidos como Comunidad de Aprendizaje. Se ha realizado un análisis del contenido de 23 informes entregados por otros tantos alumnos y alumnas de la titulación de Psicología de la Universidad de Sevilla. Los resultados se han agrupado en cinco bloques que hacen referencia a: a) para qué les ha servido colaborar en el voluntariado; b) cómo se han sentido durante esta colaboración; c) los aspectos positivos que quieren destacar de esta experiencia, d) los aspectos negativos de la misma y por último e) las propuestas de mejora que quieran formular. La principal conclusión de este trabajo es que, a juicio de los participantes, esta experiencia les ha aportado muchos beneficios a nivel profesional y personal, siendo una práctica formativa que valoran muy positivamente y que no sólo recomendarían a otros compañeros y compañeras sino que volverían a repetir.This paper presents the assessment of the voluntary students who have participated in centers established as Learning Community. We have carried out a content analysis of 23 reports of students of the degree in psychology from the University of Sevilla. The results have been grouped into five blocks that refer to: a) what benefit have they obtained from collaborating in the voluntary service; b) how have they felt during the collaboration; c) what are the positive aspects that they would like to highlight from the experience; d) what are the negative aspects of the experience and, lastly; e) improvement proposals that they would like to put forward. The main conclusion of this paper is that, in the view of its participants, this experience has brought them many benefits both at professional and personal levels, being a highly positively valued practice that they would recommend to others colleagues and they would repeat

Ecological Aspects and Conservation of Wild Grapevine Populations in the S.W. of the Iberian Peninsula

Populations of wild grapevine, Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi, were discovered in S.W. of the Iberian Peninsula over the last years. Location, ecological aspects, sanitary characteristics, including the ELISA test to detect specific virus attack, are described. In vitro propagation and conservation are also considered. The paper also contains a global description of female and male individuals. This material could be used to start breeding programs of cultivated varieties and also to restore riverbank forests, which constitute one of the worst preserved ecosystems in the area

Comunidades de aprendizaje: ¿qué aportan a los voluntarios y voluntarias universitarios?

This paper presents the assessment of the voluntary students who have participated in centers established as Learning Community. We have carried out a content analysis of 23 reports of students of the degree in psychology from the University of Sevilla. The results have been grouped into five blocks that refer to: a) what benefit have they obtained from collaborating in the voluntary service; b) how have they felt during the collaboration; c) what are the positive aspects that they would like to highlight from the experience; d) what are the negative aspects of the experience and, lastly; e) improvement proposals that they would like to put forward. The main conclusion of this paper is that, in the view of its participants, this experience has brought them many benefits both at professional and personal levels, being a highly positively valued practice that they would recommend to others colleagues and they would repeat.En este trabajo se presentan las valoraciones de los y las estudiantes universitarios que han participado como voluntarios en centros constituidos como Comunidad de Aprendizaje. Se ha realizado un análisis del contenido de 23 informes entregados por otros tantos alumnos y alumnas de la titulación de Psicología de la Universidad de Sevilla. Los resultados se han agrupado en cinco bloques que hacen referencia a: a) para qué les ha servido colaborar en el voluntariado; b) cómo se han sentido durante esta colaboración; c) los aspectos positivos que quieren destacar de esta experiencia, d) los aspectos negativos de la misma y por último e) las propuestas de mejora que quieran formular. La principal conclusión de este trabajo es que, a juicio de los participantes, esta experiencia les ha aportado muchos beneficios a nivel profesional y personal, siendo una práctica formativa que valoran muy positivamente y que no sólo recomendarían a otros compañeros y compañeras sino que volverían a repetir

Fracture toughness of cemented carbides obtained by electrical resistance sintering

The unique combination of hardness, toughness and wear resistance exhibited by WC-Co cemented carbides (hardmetals) has made them a preeminent material choice for extremely demanding applications, such as metal cutting/forming tools or mining bits, in which improved and consistent performance together with high reliability are required. The high fracture toughness values exhibited by hardmetals are mainly due to ductile ligament bridging and crack deflection (intrinsic to carbides). In this work two WC-Co grades obtained by using the electric resistance sintering technique are studied. The relationships between the process parameters (cobalt volume fraction, sintering current and time, die materials, etc.), the microstructural characteristics (porosity, cobalt volume fraction, carbide grain size, binder thickness and carbide contiguity) and mechanical properties (Vickers hardness and fracture toughness) are established and discussed. Also the presence of microstructural anisotropy and residual stresses is studied. The sintering process at 7 kA, 600 ms and 100 MPa, in an alumina die, followed by a treatment of residual stress relief (800 °C, 2 h in high vacuum), allows to obtain WC-Co pellets with the best balance between an homogeneous microstructure and mechanical behaviour.EU for funding this research with in the framework of the EU 7th Framework FoF.NMP.2013-10 608729 EFFIPRO Projec

Comment on “Pairing interaction and Galilei invariance”

A recent article by Dussel, Sofia, and Tonina studies the relation between Galilei invariance and dipole energy weighted sum rule (EWSR). The authors find that the pairing interaction, which is neither Galilei nor Lorentz invariant, produces big changes in the EWSR and in effective masses of the nucleons. They argue that these effects of the pairing force could be realistic. In this Comment we stress the validity of Galilei invariance to a very good approximation in this context of low-energy nuclear physics and show that the effective masses and the observed change in the EWSR for the electric dipole operator relative to its classical value are compatible with this symmetry.Dirección General de Investigación Científica y Técnica PB95-0533European Commission CI1*-CT94-007

Calidad y visibilidad de las revistas científicas: el caso de PNA

La difusión internacional de la investigación de calidad constituye uno de los principales retos al que se enfrentan los consejos editoriales de las publicaciones científicas. Entre ellas se encuentra PNA, una revista española especializada en investigación en Educación Matemática. En este trabajo presentamos una reflexión sobre esta problemática desde nuestra experiencia como integrantes del consejo editorial de PNA. Con la descripción del proceso seguido para dar visibilidad internacional a la revista y garantizar su calidad científica, aspiramos aportar algunos referentes operativos de utilidad para aquellas iniciativas recientes que buscan difundir la producción investigadora de calidad

Mujeres en puestos de responsabilidad dentro de las organizaciones públicas deportivas de la Comunidad de Madrid

Despite the social advances that have taken place during the last decades, the participation of women in positions of responsibility is much lower as compared to men. Similarly, this also applies to sports organizations. This article aims to give an overview of the representation of women in key leadership positions within public sports organizations of the city of Madrid and the Autonomous Comunity. One of t he most remarkable conclusions is that the higher the level of responsibility the lower is the participation by women in most of the studied organizationsA pesar de los relativos avances de las últimas décadas, el peso de las mujeres en los puestos de responsabilidad continúa siendo muy inferior al de los hombres. De igual forma, esto también ocurre en las organizaciones deportivas. En el presente artículo se pretende dar una visión global de la representación femenina en puestos directivos clave dentro de las organizaciones deportivas públicas de Madrid, ciudad y comunidad autónoma. Una de las conclusiones más llamativas es que, en la mayoría de las organizaciones estudiadas, a mayor nivel de responsabilidad, la presencia de mujeres es meno