M and F theory instantons, N = 1 supersymmetry and fractional topological charge

We analyze instanton generated superpotentials for three-dimensional N = 2 supersymmetric gauge theories obtained by compactifying on S1 N = 1 four-dimensional theories. For SU(2) with Nf = 1, we find that the vacua in the decompactification limit is given by the singular points of the Coulomb branch of the N = 2 four-dimensional theory (we also consider the massive case). The decompactification limit of the superpotential for pure gauge theories without chiral matter is interpreted in terms of 't Hooft's fractional instanton amplitudes. © World Scientific Publishing Company.This research is partially supported under grant AEN 96-1655, and by E. C. grant FMRX-CT 960012.Peer Reviewe

Accurate experimental (p, ρ, T) data for the introduction of hydrogen into the natural gas grid: Thermodynamic characterization of the nitrogen-hydrogen binary system from 240 K to 350 K and pressures up to 20 MPa

The experimental density data of the binary system nitrogen-hydrogen available at the time of the development of the equation of state for natural gases and related mixtures, GERG-2008, were limited to hydrogen contents higher than 0.15 (amount-of-substance fraction) and temperatures above 270 K. This work provides accurate experimental (p, ρ, T) data for three binary mixtures of nitrogen and hydrogen: (0.95 N2 + 0.05 H2), (0.90 N2 + 0.10 H2), and (0.50 N2 + 0.50 H2) at temperatures of (240, 250, 260, 275, 300, 325, and 350) K, thus extending the range of available experimental data to low hydrogen contents and low temperatures. The density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. The relative deviations of the experimental data from both equations of state were within the estimated uncertainty value of the equations. Therefore, the experimental data agree very well with the values estimated from the equations. The virial coefficients B(T,x), C(T,x), and D(T,x) as well as the second interaction virial coefficient for the nitrogen-hydrogen binary system were also calculated from the experimental data set at temperatures from (240 to 350) K. The resulting values agree with those from literature.2018-11-03MEC ENE2013-47812-REuropean Commission’s ENG54Junta de Castilla y León VA035U1

Líneas de producto de software (SPL) como complemento para el desarrollo de soluciones orientadas a servicios (SOA): Una revisión de la literatura

Hoy en día la construcción de software exige soluciones cada vez más ágiles y completas que optimicen la forma de implementar sistemas en entornos cada vez más complejos. Las arquitecturas orientadas a servicios –SOA- y las líneas de productos de software –SPL- son dos paradigmas arquitectónicos que reciben bastante interés por parte de investigadores y stakeholders. A lo largo de las décadas pasadas ambas estrategias se aplicaron a grandes proyectos revelando muy buenos resultados en función de características como la flexibilidad y el reúso. Sin embargo, existieron algunas limitaciones como la dependencia de tecnologías y plataformas para las líneas de productos y la ausencia de mecanismos de personalización y reutilización de artefactos en el caso de las arquitecturas orientadas a servicios. Debido a estas deficiencias y a la evidente complementariedad de ambos conceptos se procede con la realización de una revisión sistemática de la literatura que permita presentar de forma ordenada y precisa la manera en que ambos enfoques pueden ser unidos para ofrecer una solución robusta y eficiente. Con esto se busca reducir los costos y el esfuerzo de desarrollo, al igual que el tiempo de implementación y adaptación de soluciones nuevas o existentes.Today the construction of software requires increasingly flexible and complete solutions that optimize the way of implementing systems in increasingly complex environments. The service-oriented architecture -SOA- and software product lines -SPL- two architectural paradigms are receiving considerable interest by researchers and stakeholders. Over the past decades both strategies were applied to large projects revealed very good results in terms of characteristics such as flexibility and reuse. However, there were some limitations such as reliance on technologies and platforms for product lines and the absence of mechanisms for customization and reuse of artifacts in the case of service-oriented architectures. Because of these shortcomings and obvious complementarity of both concepts are applicable to the conduct of a systematic review of the literature to permit the filing of an orderly and precise fashion that both approaches can be joined to provide a robust and efficient solution. This seeks to reduce costs and development effort, as well as deployment time and adaptation of new or existing solutions

Non-Critical Poincar\'e Invariant Bosonic String Backgrounds and Closed String Tachyons

A new family of non critical bosonic string backgrounds in arbitrary space time dimension $D$ and with $ISO(1,D-2)$ Poincar\'e invariance are presented. The metric warping factor and dilaton agree asymptotically with the linear dilaton background. The closed string tachyon equation of motion enjoys, in the linear approximation, an exact solution of ``kink'' type interpolating between different expectation values. A renormalization group flow interpretation ,based on a closed string tachyon potential of type $-T^{2}e^{-T}$, is suggested.Comment: latex, 16 pages, 4 figures, misprints correcte

Non-critical Non-singular Bosonic Strings, Linear Dilatons and Holography

$AdS_{5}$ with linear dilaton and non vanishing $B$-field is shown to be a solution of the non critical string beta function equations. A non critical $(D=5)$ solution interpolating between flat space-time and $AdS_{5}$, with asymptotic linear dilaton and non vanishing $B$-field is also presented. This solution is free of space-time singularities and has got the string coupling constant everywhere bounded. Both solutions admit holographic interpretation in terms of ${\cal N}=0$ field theories. Closed string tachyon stability is also discussed.Comment: 14 pages, 5 figures, misprints corrected, reference adde

Accurate experimental (p, ρ, T) data and virial coefficients for the (methane and helium) binary system

The quality and the availability of experimental data limit the achievable accuracy of multiparameter equations of state, such as the GERG-2008. Referring to the fundamentals of this wide-range equation of state, no suitable data were available for many mixtures containing helium. This work provides accurate experimental (p, ρ, T) data for three binary mixtures of methane with helium: (0.95 (amount-of-substance fraction) CH4 + 0.05 He) and (0.90 CH4 + 0.10 He) at temperatures of (240, 250 and 260) K, and (0.50 CH4 + 0.50 He) from (240 to 400) K. This work is a continuation of a previous one which reported accurate experimental (p, ρ, T) data for the (0.95 CH4 + 0.05 He) and the (0.90 CH4 + 0.10 He) binary mixtures in the temperature range from the (250 to 400) K. All density measurements were performed by using a single-sinker densimeter with magnetic suspension coupling at pressures up to 20 MPa. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. Deviations from the GERG-2008 are much larger than from the AGA8-DC92 (up to –6.5 %). These deviations increased with decreasing temperature, with increasing pressure, and with increasing helium fraction. In contrast, deviations from the AGA8-DC92 are within the 0.5 % band. The experimental values were also used to calculate the second interaction virial coefficient for this mixture.2018-05-30MEC ENE2013-47812-REuropean Commission ENG5

Experimental determination of (p, ρ, T) data for binary mixtures of methane and helium

Innovación EducativaThe basis for the development and evaluation of equations of state for mixtures is experimental data for several thermodynamic properties. The quality and the availability of experimental data limit the achievable accuracy of the equation. Referring to the fundamentals of GERG-2008 wide-range equation of state, no suitable data were available for many mixtures containing secondary natural gas components. This work provides accurate experimental (p, ρ, T) data for two binary mixtures of methane with helium (0.95 (amount-of-substance fraction) CH4 + 0.05 He and 0.90 CH4 + 0.10 He). Density measurements were performed at temperatures between 250 K and 400 K and pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. Experimental data were compared with the corresponding densities calculated from the GERG-2008 and the AGA8-DC92 equations of state. Deviations from GERG-2008 were found within a 2 % band for the (0.95 CH4 + 0.05 He) mixture but exceeded the 3 % limit for the (0.95 CH4 + 0.05 He) mixture. The highest deviations were observed at 250 K and pressures between 17 and 19 MPa. Values calculated from AGA8-DC92, however, deviated from the experimental data by only 0.1 % at high pressures and exceeded the 0.2 % limit only at temperatures of 300 K and above, for the (0.90 CH4 + 0.10 He) mixture.MEC ENE2013-47812-RJunta de Castilla y León Regional VA391A12-1European Commission's ENG5

GMM-based classifiers for the automatic detection of obstructive sleep apnea

The aim of automatic pathological voice detection systems is to serve as tools, to medical specialists, for a more objective, less invasive and improved diagnosis of diseases. In this respect, the gold standard for those system include the usage of a optimized representation of the spectral envelope, either based on cepstral coefficients from the mel-scaled Fourier spectral envelope (Mel-Frequency Cepstral Coefficients) or from an all-pole estimation (Linear Prediction Coding Cepstral Coefficients) forcharacterization, and Gaussian Mixture Models for posterior classification. However, the study of recently proposed GMM-based classifiers as well as Nuisance mitigation techniques, such as those employed in speaker recognition, has not been widely considered inpathology detection labours. The present work aims at testing whether or not the employment of such speaker recognition tools might contribute to improve system performance in pathology detection systems, specifically in the automatic detection of Obstructive Sleep Apnea. The testing procedure employs an Obstructive Sleep Apnea database, in conjunction with GMM-based classifiers looking for a better performance. The results show that an improved performance might be obtained by using such approach