The Dynamical Behaviour of Test Particles in a Quasi-Spherical Spacetime and the Physical Meaning of Superenergy

We calculate the instantaneous proper radial acceleration of test particles (as measured by a locally defined Lorentzian observer) in a Weyl spacetime, close to the horizon. As expected from the Israel theorem, there appear some bifurcations with respect to the spherically symmetric case (Schwarzschild), which are explained in terms of the behaviour of the superenergy, bringing out the physical relevance of this quantity in the study of general relativistic systems.Comment: 14 pages, Latex. 4 figures. New references added. Typos corrected. To appear in Int. J. Theor. Phy

Copernicus Marine Service ocean state report, issue 4

This is the final version. Available from Taylor & Francis via the DOI in this record. FCT/MCTE

Image, Speech and Intelligent Systems

This paper presents a bound on the performance of a Support Vector Machine obtained within the PAC-Bayes framework. The bound is computed by means of the estimation of a prior of the distribution of SVM classifiers given a particular dataset, and the use of this prior in the PAC-Bayes generalisation bound. The quality of the bound is tested in a model selection task, where it is compared against other procedures to select models based on other PAC-Bayes bounds and ten fold cross-validation. Furthermore, we introduce an algorithm to approximately optimise the new bound and test it against a standard SVM both in terms of bound value and test set error.

Abstract

Automatic methods for music navigation and music recommendation exploit the structure in the music to carry out a meaningful exploration of the “song space”. To get a satisfactory performance from such systems, one should incorporate as much information about songs similarity as possible; however, how to do so is not obvious. In this paper, we build on the ideas of the Probabilistic Latent Semantic Analysis (PLSA) that have been successfully used in the document retrieval community. Under this probabilistic framework, any song will be projected into a relatively low dimensional space of “latent semantics”, in such a way that all observed similarities can be satisfactorily explained using the latent semantics. Therefore, one can think of these semantics as the real structure in music, in the sense that they can explain the observed similarities among songs. The suitability of the PLSA model for representing music structure is studied in a simplified scenario consisting of 4412 songs and two similarity measures among them. The results suggest that the PLSA model is a useful framework to combine different sources of information, and provides a reasonable space for song representation.

Abstract

Automatic methods for music navigation and music recommendation exploit the structure in the music to carry out a meaningful exploration of the “song space”. To get a satisfactory performance from such systems, one should incorporate as much information about songs similarity as possible; however, how to do so is not obvious. In this paper, we build on the ideas of the Probabilistic Latent Semantic Analysis (PLSA) that have been successfully used in the document retrieval community. Under this probabilistic framework, any song will be projected into a relatively low dimensional space of “latent semantics”, in such a way that all observed similarities can be satisfactorily explained using the latent semantics. Therefore, one can think of these semantics as the real structure in music, in the sense that they can explain the observed similarities among songs. The suitability of the PLSA model for representing music structure is studied in a simplified scenario consisting of 4412 songs and two similarity measures among them. The results suggest that the PLSA model is a useful framework to combine different sources of information, and provides a reasonable space for song representation.

Voxel Selection in MRI through Bagging and Conformal Analysis: Application to Detection of Obsessive Compulsive Disorder

In this work we apply a multivariate feature selection method based on bagging linear SVMs to construct a classifier able to differentiate among control subjects and patients with obsessive compulsive disorder (OCD). Our method selects sets of voxels that are relevant for the detection of the disease. The voxel selection is completed with a conformal analysis based refinement that controls over fitting and dramatically reduces the test error rate of the final classifier. Furthermore, the resulting discrimination pattern is organized in regions that show great agreement with those found by traditional methods used in OCD problems, achieving cleaner and more accurate region maps. © 2012 IEEE

Dissecting the transcriptional program of phosphomannomutase 2-deficient cells: Lymphoblastoide B cell lines as a valuable model for congenital disorders of glycosylation studies

©. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in [Glycobiology]. To access the final edited and published work see[https://doi.org/10.1093/glycob/cwab087]Congenital disorders of glycosylation (CDG) include 150 disorders constituting in genetically and clinically heterogeneous diseases, showing significant glycoprotein hypoglycosylation that leads to pathological consequences on multiple organs and systems whose underlying mechanisms are not yet understood. A few cellular and animal models have been used to study specific CDG characteristics, although they have given limited information due to the few CDG mutations tested and the still missing comprehensive molecular and cellular basic research. Here, we provide specific gene expression profiles, based on ribonucleic acid (RNA) microarray analysis, together with some biochemical and cellular characteristics of a total of nine control Epstein– Barr virus-transformed lymphoblastoid B cell lines (B-LCL) and 13 CDG B-LCL from patients carrying severe mutations in the phosphomannomutase 2 (PMM2) gene, strong serum protein hypoglycosylation and neurological symptoms. Significantly dysregulated genes in PMM2-CDG cells included those regulating stress responses, transcription factors, glycosylation, motility, cell junction and, importantly, those related to development and neuronal differentiation and synapse, such as carbonic anhydrase 2 (CA2) and ADAM23. PMM2-CDG-associated biological consequences involved the unfolded protein response, RNA metabolism and the endoplasmic reticulum, Golgi apparatus and mitochondria components. Changes in the transcriptional and CA2 protein levels are consistent with the CDG physiopathology. These results demonstrate the global transcriptional impact in phosphomannomutase 2-deficient cells, reveal CA2 as a potential cellular biomarker and confirm B-LCL as an advantageous model for CDG studies

Real-world data on the effectiveness and safety of teriflunomide in patients with relapsing–remitting multiple sclerosis: The EFFECT study

Introduction: The objective of the present study was to evaluate the effectiveness and safety of teriflunomide in relapsing–remitting multiple sclerosis (RRMS) patients treated in a real-world setting. Methods: This retrospective study was conducted at neurology departments of 15 hospitals in 2 Spanish Autonomous Regions. The primary endpoint was annualized relapse rate (ARR) during teriflunomide treatment. Secondary endpoints included changes in Expanded Disability Status Scale (EDSS), radiological activity, and adverse events (AEs). Results: 485 patients (72.2% women, mean of 36.5 years) were included; 74.8% had previously received other disease-modifying treatment. EDSS score at inclusion was 2.0. Mean time receiving teriflunomide was 2.5 years. The ARR during teriflunomide treatment was 0.16, a 20% lower than at baseline (0.20), although the difference did not reach statistical significance (P = 0.098). The mean number of relapses significantly decreased after teriflunomide initiation, with 0.17 relapses at month 12, 0.11 at month 24, and 0.13 at month 36, compared to 0.50 in the year before teriflunomide initiation (P < 0.001). EDSS scores were maintained over the study period. The percentage of patients without gadolinium-enhanced T1-weighted lesions was significantly higher after teriflunomide (P = 0.01), and the percentage of patients without new/enlarged lesions on T2 remained stable. The proportion of patients with AEs was 41.9% (1.4% serious), being hair thinning (19.4%) and gastrointestinal disorders (18.4%) the most frequent. Discussion: Over teriflunomide treatment, the ARR was low, radiologic evidence of disease activity decreased, and disability stabilized. These findings, together with the acceptable safety profile observed, support the use of teriflunomide in RRMS patients. Resumen: Introducción: El objetivo de este estudio es evaluar la efectividad y seguridad de teriflunomida en pacientes con esclerosis múltiple remitente-recurrente (EMRR) en un contexto del mundo real. Métodos: Realizamos un estudio retrospectivo de pacientes atendidos en los servicios de neurología de 15 hospitales localizados en dos comunidades autónomas de España. La variable principal fue la tasa anualizada de brotes (TAB) durante el tratamiento con teriflunomida. Como variables secundarias analizamos los cambios en la puntuación de la escala Expanded Disability Status Scale (EDSS), la actividad radiológica y los efectos adversos. Resultados: Nuestra muestra incluyó 485 pacientes (72,2% mujeres; edad media de 36,5 años); 74,8% de los pacientes habían recibido otro tratamiento modificador de la enfermedad con anterioridad. La puntuación media en la EDSS al inicio fue de 2,0. Los pacientes recibieron teriflunomida durante una media de 2,5 años. Durante el tratamiento, la TAB se redujo en un 20% respecto al inicio (0,16 frente a 0,20), aunque la diferencia no fue estadísticamente significativa (P = 0,098). El número medio de brotes se redujo significativamente tras iniciar el tratamiento con teriflunomida, pasando de 0,50 brotes en el año anterior al inicio del estudio a 0,17 brotes a los 12 meses de tratamiento, 0,11 brotes a los 24 meses y 0,13 brotes a los 36 meses (p < 0,001). Las puntuaciones en la EDSS se mantuvieron estables a lo largo del estudio. El porcentaje de pacientes que no mostraron lesiones captadoras de gadolinio en secuencias potenciadas en T1 fue significativamente mayor tras el tratamiento con teriflunomida (p = 0,01), mientras que el porcentaje de pacientes que no presentaron lesiones nuevas o un aumento en el tamaño de lesiones previas en secuencias potenciadas en T2 permaneció estable. Se reportaron efectos adversos en 41,9% de los pacientes (graves en 1,4%); los más frecuentes fueron la pérdida de cabello (19,4%) y los problemas gastrointestinales (18,4%). Conclusión: Durante el periodo de tratamiento con teriflunomida, la TAB y la actividad radiológica de la enfermedad disminuyeron, mientras que el grado de discapacidad permaneció estable. Estos hallazgos, junto con el aceptable perfil de seguridad de teriflunomida, apoyan el uso del fármaco en pacientes con EMRR