761 research outputs found
Pharmacogenetic Variation and Its Clinical Relevance in a Latin American Rural Population
Latin-American populations have been largely underrepresented in genomic studies of drug response and disease susceptibility. In this paper, we present a genome-wide Chilean dataset from Talca based on the Illumina Global Screening Array. This let us to compare the frequency of gene variants involved in response to drugs among our population and others, taking data from the 1000 Genomes Project. We found four single-nucleotide polymorphisms with low prevalence in Chileans when compared with African, Amerindian, East and South Asian, and European populations: rs2819742 (RYR2), rs2631367 (SLC22A5), rs1063320 (HLA-G), and rs1042522 (TP53). Moreover, two markers showed significant differences between lower and higher proportion of Mapuche ancestry groups: rs1719247 (located in an intergenic region in chromosome 15; p-value = 6.17 × 10-5, Bonferroni corrected p-value = 0.02) and rs738409 (A nonsynonymous gene variant in the PNPLA3 gene; p-value = 9.02 × 10-5, Bonferroni corrected p-value = 0.04). All of these polymorphisms have been shown to be associated with diverse pathologies, such as asthma, cancer, or chronic hepatitis B, or to be involved in a different response to drugs, such as metformin, HMG-CoA reductase inhibitors, or simvastatin. The present work provides a pharmacogenetic landscape of an understudied Latin American rural population and supports the notion that pharmacogenetic studies in admixed populations should consider ancestry for a higher accuracy of the results. Our study stresses the relevance of the pharmacogenomic research to provide guidance for a better choice of the best treatment for each individual in a population with admixed ancestry. Keywords: Chile; Latin-American; ancestry; personalized medicine; pharmacogenetics; single nucleotide polymorphism
Robust ASR using Support Vector Machines
The improved theoretical properties of Support Vector Machines with respect to other machine learning alternatives due to their max-margin training paradigm have led us to suggest them as a good technique for robust speech recognition. However, important shortcomings have had to be circumvented, the most important being the normalisation of the time duration of different realisations of the acoustic speech units.
In this paper, we have compared two approaches in noisy environments: first, a hybrid HMM–SVM solution where a fixed number of frames is selected by means of an HMM segmentation and second, a normalisation kernel called Dynamic Time Alignment Kernel (DTAK) first introduced in Shimodaira et al. [Shimodaira, H., Noma, K., Nakai, M., Sagayama, S., 2001. Support vector machine with dynamic time-alignment kernel for speech recognition. In: Proc. Eurospeech, Aalborg, Denmark, pp. 1841–1844] and based on DTW (Dynamic Time Warping). Special attention has been paid to the adaptation of both alternatives to noisy environments, comparing two types of parameterisations and performing suitable feature normalisation operations. The results show that the DTA Kernel provides important advantages over the baseline HMM system in medium to bad noise conditions, also outperforming the results of the hybrid system.Publicad
Field analysis of solar PV-based collective systems for rural electrification.
This article analyses the long-term performance of collective off-grid photovoltaic (PV) systems in rural areas. The use of collective PV systems for the electrification of small medium-size villages in developing countries has increased in the recent years. They are basically set up as stand-alone installations (diesel hybrid or pure PV) with no connection with other electrical grids. Their particular conditions (isolated) and usual installation places (far from commercial/industrial centers) require an autonomous and reliable technology. Different but related factors affect their performance and the energy supply; some of them are strictly technical but others depend on external issues like the solar energy resource and users’ energy and power consumption. The work presented is based on field operation of twelve collective PV installations supplying the electricity to off-grid villages located in the province of Jujuy, Argentina. Five of them have PV generators as unique power source while other seven include the support of diesel groups. Load demand evolution, energy productivity and fuel consumption are analyzed. Besides, energy generation strategies (PV/diesel) are also discussed
Microscopic transition potential: Determination of and coupling constants
A transition potential, based on an effective
quark-quark interaction and a constituent quark cluster model for baryons, is
derived in the Born-Oppenheimer approach. The potential shows significant
differences with respect to those obtained by a direct scaling of the
nucleon-nucleon interaction. From its asymptotic behavior we extract the values
of and coupling constants in a
particular coupling schemeComment: 15 eps figures, Accepted for publication in Phys. Rev.
GJ357: A low-mass planetary system uncovered by precision radial-velocities and dynamical simulations
We report the detection of a new planetary system orbiting the nearby M2.5V
star GJ357, using precision radial-velocities from three separate echelle
spectrographs, HARPS, HiRES, and UVES. Three small planets have been confirmed
in the system, with periods of 9.125+/-0.001, 3.9306+/-0.0003, and 55.70+/-0.05
days, and minimum masses of 3.33+/-0.48, 2.09+/-0.32, and 6.72+/-0.94 Me,
respectively. The second planet in our system, GJ357c, was recently shown to
transit by the Transiting Exoplanet Survey Satellite (TESS; Luque et al. 2019),
but we could find no transit signatures for the other two planets. Dynamical
analysis reveals the system is likely to be close to coplanar, is stable on
Myrs timescales, and places strong upper limits on the masses of the two
non-transiting planets b and d of 4.25 and 11.20 Me, respectively. Therefore,
we confirm the system contains at least two super-Earths, and either a third
super-Earth or mini-Neptune planet. GJ357b & c are found to be close to a 7:3
mean motion resonance, however no libration of the orbital parameters was found
in our simulations. Analysis of the photometric lightcurve of the star from the
TESS, when combined with our radial-velocities, reveal GJ357c has an absolute
mass, radius, and density of 2.248+0.117-0.120 Me, 1.167+0.037-0.036 Re, and
7.757+0.889-0.789 g/cm3, respectively. Comparison to super-Earth structure
models reveals the planet is likely an iron dominated world. The GJ357 system
adds to the small sample of low-mass planetary systems with well constrained
masses, and further observational and dynamical follow-up is warranted to
better understand the overall population of small multi-planet systems in the
solar neighbourhood.Comment: Manuscript accepted to MNRAS 15/10/201
Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)
The macrozoobenthos of Mejillones Bay (23°S; Humboldt Current) was quantitatively investigated over a 7-year period from austral summer 1995/1996 to winter 2002. About 78 van Veen grab samples taken at six stations (5, 10, 20 m depth) provided the basis for the analysis of the distribution of 60 species and 28 families of benthic invertebrates, as well as of their abundance and biomass. Mean abundance (2,119 individuals m-2) was in the same order compared to a previous investigation; mean biomass (966 g formalin wet mass m-2), however, exceeded prior estimations mainly due to the dominance of the bivalve Aulacomya ater. About 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (H', Log e) was 1.54 ± 0.58 with a maximum at 20 m (1.95 ± 0.33); evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%). About 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a significant difference between the shallow and the deeper stations. Gammarid amphipods and the polychaete family Nephtyidae characterized the 5-mzone, the molluscs Aulacomya ater, Mitrella unifasciata and gammarids the intermediate zone, while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depth zones did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997–1998, in contrast to what was observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current system
BioDR : semantic indexing networks for biomedical document retrieval
In Biomedical research, retrieving documents that match an interesting query is a task performed quite
frequently. Typically, the set of obtained results is extensive containing many non-interesting documents
and consists in a flat list, i.e., not organized or indexed in any way. This work proposes BioDR, a novel
approach that allows the semantic indexing of the results of a query, by identifying relevant terms in
the documents. These terms emerge from a process of Named Entity Recognition that annotates occurrences
of biological terms (e.g. genes or proteins) in abstracts or full-texts. The system is based on a learning
process that builds an Enhanced Instance Retrieval Network (EIRN) from a set of manually classified
documents, regarding their relevance to a given problem. The resulting EIRN implements the semantic
indexing of documents and terms, allowing for enhanced navigation and visualization tools, as well as
the assessment of relevance for new documents.Fundação para a Ciência e a Tecnologia (FCT)Maria Barbeito” contract XuntaHUELLA financed by the Consellería de Sanidade (Xunta de Galicia de Galicia
Waterborne outbreak of tularemia associated with crayfish fishing.
In 1997, an outbreak of human tularemia associated with hare-hunting in central Spain affected 585 patients. We describe the identification of Francisella tularensis biovar palaearctica in a second outbreak of ulceroglandular tularemia associated with crayfish (Procambarus clarkii) fishing in a contaminated freshwater stream distant from the hare-associated outbreak. The second outbreak occurred 1 year after the first
Surviving sepsis campaign guidelines for severe sepsis and septic shock: implementation and outcome of a 3-year follow up
Managing irrelevant knowledge in CBR models for unsolicited e-mail classification
The problem of unsolicited e-mail has been increasing during recent years. Fortunately, some advanced technologies have been successfully applied to spam filtering, achieving promising results. Recently, we have introduced SpamHunting, a successful spam filter able to address the concept drift problem by combining a relevant term identification technique with an evolving sliding window strategy. Several successful spam filtering techniques use continuous learning strategies to achieve better adaptation capabilities and address concept drift issues. Nevertheless, due to the presence of concept drift and hidden changes in the environment, the presence of obsolete and irrelevant knowledge becomes a serious drawback. Soon after the launch of the filter, many decisions are made based on irrelevant and/or obsolete knowledge. Therefore, in such a situation, the use of forgetting strategies is as important as the implementation of continuous learning approaches. In this paper we introduce a novel technique designed for identifying and removing the obsolete and irrelevant knowledge that has accumulated over to the passage of time. We have carried out several experiments to test for the suitability of our proposal showing the results obtained and its applicability
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