Muestreo como un requisito fundamental en las ciencias experimentales (Sampling as a basic requirement in experimental sciences)

Se presentan los fundamentos básicos de muestreo, enfatizando los requisitos para determinar el tamaño óptimo de la muestra. Se discuten el muestreo absoluto y relativo y la comparación entre ellos. Se destaca la relevancia del tipo de distribución espacial en el diseño de muestreo y presenta varios modelos de uso actual para la determinación de ella. Se presentan de manera somera tres modelos de uso común, y finalmente, y por su relevancia práctica e económica, se discuten las cinco modalidades de muestreo secuencial. The fundamentals of sampling with emphasis on determining the optimal sample size are given. Absolute and relative sampling as well as the comparison among them is stressed. The importance of spatial distribution in sampling design is noted and various current models for its determination are offered. Three current models are discussed briefly, and finally, due to the practical and economical significance of sequential sampling, five different types of this kind of sampling design are fully addressed

Improving the performance of polyamide Nano-filtration membrane in acidic media by incorporation of modified multi-walled carbon nanotubes

Postprint (author's final draft

Comparing human and automatic speech recognition in a perceptual restoration experiment

Speech that has been distorted by introducing spectral or temporal gaps is still perceived as continuous and complete by human listeners, so long as the gaps are filled with additive noise of sufficient intensity. When such perceptual restoration occurs, the speech is also more intelligible compared to the case in which noise has not been added in the gaps. This observation has motivated so-called 'missing data' systems for automatic speech recognition (ASR), but there have been few attempts to determine whether such systems are a good model of perceptual restoration in human listeners. Accordingly, the current paper evaluates missing data ASR in a perceptual restoration task. We evaluated two systems that use a new approach to bounded marginalisation in the cepstral domain, and a bounded conditional mean imputation method. Both methods model available speech information as a clean-speech posterior distribution that is subsequently passed to an ASR system. The proposed missing data ASR systems were evaluated using distorted speech, in which spectro-temporal gaps were optionally filled with additive noise. Speech recognition performance of the proposed systems was compared against a baseline ASR system, and with human speech recognition performance on the same task. We conclude that missing data methods improve speech recognition performance in a manner that is consistent with perceptual restoration in human listeners

Werner states and the two-spinors Heisenberg anti-ferromagnet

We ascertain, following ideas of Arnesen, Bose, and Vedral concerning thermal entanglement [Phys. Rev. Lett. {\bf 87} (2001) 017901] and using the statistical tool called {\it entropic non-triviality} [Lamberti, Martin, Plastino, and Rosso, Physica A {\bf 334} (2004) 119], that there is a one to one correspondence between (i) the mixing coefficient $x$ of a Werner state, on the one hand, and (ii) the temperature $T$ of the one-dimensional Heisenberg two-spin chain with a magnetic field $B$ along the $z-$axis, on the other one. This is true for each value of $B$ below a certain critical value $B_c$. The pertinent mapping depends on the particular $B-$value one selects within such a range

Highly effective SERS nanopattern substrate. The enhancement is demonstrated using thiophenol as a molecular probe

The number of different types of Surface-enhanced Raman Scattering (SERS) substrates available for experimentation is increasing at high speed. New alternatives are introduced and explored every year in the literature including both novel nano-particles in solution as well as self-assembled or engineered structures with different levels of control over their optical properties. In this work silver nanopattern obtained by the nano-sphere lithography approach was prepared and characterized by AFM. This method basically exploits the regular patterns formed by self-assembly of dielectric (polystyrene, PS) nano-spheres on a surface upon drying. The evaporation of a silver film on top of the array can be followed by the lift-off of the nano-spheres themselves in which case an array of interstitial sites is left on the surface [1-2] (Fig. 1). We have observed in the AFM images that the shape of the nanopatterns is regular but the surface is rough and they are homogeneously distributed with dimensions in the sub-wavelength range.SERS properties of this substrate were examined by using thiophenol (TP) as molecular probe through the preparation of self-assembled monolayer (SAM) by dipping the substrates for 1h in 0.1mM solution of TP in CH2Cl2 at the temperature of 25ºC. Samples were subsequently rinsed with solutions solvents and dried before scanning. The surface interaction of this molecule has been studied by several groups and the most significant Raman change after the adsorption is the disappearance of the S-H stretching mode at about 2566 cm-1 in the SERS spectrum and indicating that an Ag-S bond has been formed [3]. The reproducibility on different areas of this substrate has been analyzed by using this molecular probe concluding that a fairly homogeneous distribution of the SERS intensity is observed (Fig. 2) which is a prerequisite for applications as ultrasensitive sensing assemblies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

First Report of Homothallic Isolates of Phytophthora infestans in Commercial Potato Crops (Solanum tuberosum) in the Toluca Valley, Mexico

Phytophthora infestans causes severe symptoms of wilt disease on potato crops (Solanum tuberosum) in the Toluca Valley (Mexico)despite the use of fungicides. P. infestans oospores produced by sexual reproduction can survive in the soil for many years, resisting harsh environments

Quintessence Cosmology and the Cosmic Coincidence

Within present constraints on the observed smooth energy and its equation of state parameter, it is important to find out whether the smooth energy is static (cosmological constant) or dynamic (quintessence). The most dynamical quintessence fields observationally allowed are now still fast-rolling and no longer satisfy the tracker approximation if the equation of state parameter varies moderately with cosmic scale. We are optimistic about distinguishing between a cosmological constant and appreciably dynamic quintessence, by measuring average values for the effective equation of state parameter. However, reconstructing the quintessence potential from observations of any scale dependence appears problematic in the near future. For our flat universe, at present dominated by smooth energy in the form of either a cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction to be maximal at the observed smooth energy/matter ratio. Identifying this collapsed fraction as a conditional probability for habitable galaxies, we infer that the prior distribution is flat. Interpreting this prior as a distribution over theories, rather than as a distribution over unobservable subuniverses, leads us to heuristic predictions about the class of future quantum cosmology theories and the static or quasi-static nature of the smooth energy.Comment: Typos corrected, as presented at Cosmo-01 Workshop, Rovaniemi, Finland and accepted for publication in Physical Review D. 9 pages, 4 figure

Aromáticas y medicinales en Paravachasca: promoviendo el aprovechamiento sustentable

In Córdoba province, the use and commercialization of native aromatic and medicinal plants (AMP) are widespread practices adopted by the population. This context defines the need for the development of adequate technologies and its transfer to the environment in order to revalue and conserve the resource; the proposed objectives were to promote the use, production and sustainable use of native AMP in Valle de Paravachasca and to train social actors in management practices. In order to address sustainable practices in the use of AMP and their cultivation, the training and learning of students, teachers, producers and policy makers was carried out through journeys, practical workshops in fields and exchange of knowledge. The development of new knowledge was achieved through active participation in the different stages carried out. It is worth highlighting that students and teachers showed great interest in the activities and spaces for intervention on the subject. The participation of family groups in relation to new concerns and the return of practices and knowledge was visualized, allowing progress towards new objectives in pursuit of regional development. The interrelation and participation made it possible to detect new problems for future challenges in university research and outreach.En la provincia de Córdoba el uso y comercialización de plantas aromáticas y medicinales (PAM) nativas son prácticas difundidas y arraigadas en la población. Sin embargo, las prácticas de colecta no se realizan en forma sustentable, generando la degradación de los recursos y consecuentemente la pérdida de ingresos familiares. Este contexto define la necesidad del desarrollo de tecnologías adecuadas y su transferencia al medio para revalorizar y conservar el recurso. Los objetivos propuestos fueron promover el aprovechamiento, producción y uso sustentable de PAM nativas en el Valle de Paravachasca y capacitar a los actores sociales en las prácticas de manejo. Para abordar las prácticas sustentables en el aprovechamiento de las PAM y su cultivo se consideró la capacitación y aprendizaje de alumnos, docentes, productores y decisores políticos a través de jornadas, talleres de prácticas a campo e intercambio de saberes. La incorporación de nuevos conocimientos se logró mediante la participación activa en las instancias desarrolladas. Se destacó el gran interés de alumnos y docentes en las actividades y espacios de acción sobre la temática. Se visualizó la participación de los grupos familiares en nuevas inquietudes y el retorno de prácticas y conocimientos, permitiendo avanzar hacia nuevos objetivos en pos de un desarrollo regional. La interrelación y participación permitieron detectar nuevas problemáticas para futuros desafíos en la investigación y extensión universitaria

Evolution of the Schr\"odinger--Newton system for a self--gravitating scalar field

Using numerical techniques, we study the collapse of a scalar field configuration in the Newtonian limit of the spherically symmetric Einstein--Klein--Gordon (EKG) system, which results in the so called Schr\"odinger--Newton (SN) set of equations. We present the numerical code developed to evolve the SN system and topics related, like equilibrium configurations and boundary conditions. Also, we analyze the evolution of different initial configurations and the physical quantities associated to them. In particular, we readdress the issue of the gravitational cooling mechanism for Newtonian systems and find that all systems settle down onto a 0--node equilibrium configuration.Comment: RevTex file, 19 pages, 26 eps figures. Minor changes, matches version to appear in PR

Feature Extraction and Classification of Biosignals - Emotion Valence Detection from EEG Signals

In thisworkavalencerecognitionsystembasedonelectroencephalogramsispresented.Theperformanceof the systemisevaluatedfortwosettings:singlesubjects(intra-subject)andbetweensubjects(inter-subject). The featureextractionisbasedonmeasuresofrelativeenergiescomputedinshorttimeintervalsandcertain frequencybands.Thefeatureextractionisperformedeitheronsignalsaveragedoveranensembleoftrialsor on single-trialresponsesignals.Thesubsequentclassificationstageisbasedonanensembleclassifier,i.e.a random forestoftreeclassifiers.Theclassificationisperformedconsideringtheensembleaverageresponsesof all subjects(inter-subject)orconsideringthesingle-trialresponsesofsinglesubjects(intra-subject).Applying a properimportancemeasureoftheclassifier,featureeliminationhasbeenusedtoidentifythemostrelevant features of the decision making.info:eu-repo/semantics/publishedVersio