First CLADAG data mining prize : data mining for longitudinal data with different marketing campaigns

The CLAssification and Data Analysis Group (CLADAG) of the Italian Statistical Society recently organised a competition, the 'Young Researcher Data Mining Prize' sponsored by the SAS Institute. This paper was the winning entry and in it we detail our approach to the problem proposed and our results. The main methods used are linear regression, mixture models, Bayesian autoregressive and Bayesian dynamic models

Numerical optimal control for HIV prevention with dynamic budget allocation

This paper is about numerical control of HIV propagation. The contribution of the paper is threefold: first, a novel model of HIV propagation is proposed; second, the methods from numerical optimal control are successfully applied to the developed model to compute optimal control profiles; finally, the computed results are applied to the real problem yielding important and practically relevant results.Comment: Submitted pape

Reconstruction of the second layer of Ag on Pt(111)

The reconstruction of an Ag monolayer on Ag/Pt(111) is analyzed theoretically, employing a vertically extended Frenkel-Kontorova model whose parameters are derived from density functional theory. Energy minimization is carried out using simulated quantum annealing techniques. Our results are compatible with the STM experiments, where a striped pattern is initially found which transforms into a triangular reconstruction upon annealing. In our model we recognize the first structure as a metastable state, while the second one is the true energy minimum

Análisis crítico de la controversia del uso de animales en las investigaciones científicas biomédicas

En los últimos años, se ha generado una enconada discusión por parte de grupos proteccionistas y entidades científicas vigentes respecto al uso de animales en el laboratorio. Si bien es cierto, que bajo la perspectiva actual la historia ha mostrado abusos y acciones denigrantes hacia los animales en la sociedad humana, el progreso de los conocimientos y el desarrollo de la bioética, ha generado actitudes más humanitarias con respecto a este tema. Los reclamos de estos grupos defensores de los animales han generado ideas distorsionadas respecto al uso de ellos en la investigación científica, en gran parte por el carácter dogmático de sus argumentos y por una visión limitada y en extremo estereotipada de la actividad científica de investigación. En la presente revisión, se consideran aspectos históricos de la relación hombre-animal; discusión del entorno y creencias de épocas remotas y su posterior evolución en el tiempo; análisis crítico de la publicación de Rusell y Burch como hito en la investigación científica humanizada a través de sus 3 R y la presentación de argumentos tan básicamente razonables que resulta hasta innecesaria cualquier justificación sobre la existencia de la actividad científica biológica en la humanidad.In the past years a sustained issue has been generated between certain activists groups and scientific institutions regarding the use of animals in the biological research. A revision of the historical aspects about the interaction of humans and animals in the past clearly revealed abominable abuses to animals. However, in the present times the evolution of bioethics and the generation of scientific information have put into evidence a significant change in the human attitudes to animals in biological research. However, the activist’s claims have generated distorted ideas regarding the use of animals in experimental research, mainly due to the dogmatic character of their arguments, and the propagation of a stereotyped vision about research procedures and researcher’s attitudes to animals use. In the present revision, history aspects about the relationship of human-animal in the evolving society; discussion about the context and beliefs of the society at that time; critical review about the 3 Rs of Rusell and Burch historical landmark in the humane experimental techniques, and presentation of scientific arguments justifying use of animals in biological research are considered.Fil: Álvarez, Edgardo O.. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: Ratti, Silvia. Universidad Nacional de Cuyo. Facultad de Ciencias Médica

Análisis de conceptos básicos de memoria y aprendizaje : ¿Hasta qué punto los "dogmas" cognitivos son realmente "dogmas"?

El aprendizaje como proceso se puede considerar un avance evolutivo importante para todos los sistemas vivientes que lo adquirieron en las tempranas épocas del desarrollo de la vida. La percepción de un entorno que tiene “pasado" y “presente" permitió a los animales primitivos adquirir una visión más completa del mundo que los rodeaba. El uso cognitivo de la información que está disponible en un sistema viviente se le reconoce ahora como “aprendizaje". A pesar que han pasado muchos años y muchos investigadores han estado muy comprometidos en el estudio de la memoria y el aprendizaje, su intrincada naturaleza todavía no se comprende bien. En este trabajo se amplían muchos términos comunes en la investigación de este tema, como memoria, aprendizaje y ensayo redefiniéndose en un contexto más acotado con la intención de uniformar su comprensión. Se vuelve a discutir el modelo de aprendizaje en términos de un “circuito de aprendizaje". También se amplía el concepto unificador de “engrama de la unidad vectorial de la memoria" para el proceso de aprendizaje y el almacenamiento de la información, descrito con anterioridad. Finalmente, las implicaciones del modelo propuesto se consideran en el contexto de patologías que producen déficit de memoria, evaluándose las predicciones del modelo con la evidencia comportamental de pacientes con lesiones localizadas en ciertas partes del cerebro.Learning can be considered a process that gave to living systems a significant evolutionary advance in the history of life. The capacity to distinguish that events in the environment have “past" or “present" permitted the primitive evolving organisms to acquire a convenient enriched vision of the their surrounding world. The appropriate use of the information available as experience in an organism now it is known as learning. In spite of many years of intense research, the complete understanding of memory and learning still is not clear. Debate and disagreements about the intrinsic nature of this neural process in the scientific community did not help in these years to sediment a clear-cut knowledge about this important brain function. Part of these issues appears to be linked to the semantic use of some terms implying different meanings to different investigators, and the strong belief in interpretations about learning that in time has been considered dogmas. In the present work, intent to emphasize the meaning of many terms by limiting its significance and extending an alternative point of view previously presented elsewhere, about memory and learning is done.Fil: Álvarez, Edgardo O.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología.Fil: Ratti, Silvia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área Farmacología

On the improvement of the low energy neutrino factory

The low energy neutrino factory has been proposed as a very sensitive setup for future searches for CP violation and matter effects. Here we study how its performance is affected when the experimental specifications of the setup are varied. Most notably, we have considered the addition of the 'platinum' nu_{mu} -> nu_{e} channel. We find that, whilst theoretically the extra channel provides very useful complementary information and helps to lift degeneracies, its practical usefulness is lost when considering realistic background levels. Conversely, an increase in statistics in the 'golden' nu_{e} -> nu_{mu} channel and, to some extent, an improvement in the energy resolution, lead to an important increase in the performance of the facility, given the rich energy dependence of the 'golden' channel at these energies. We show that a low energy neutrino factory with a baseline of 1300 km, muon energy of 4.5 GeV, and either a 20 kton totally active scintillating detector or 100 kton liquid argon detector, can have outstanding sensitivity to the neutrino oscillation parameters theta13, delta and the mass hierarchy. For our estimated exposure of 2.8 x 10^{23} kton x decays per muon polarity, the low energy neutrino factory has sensitivity to theta13 and delta for sin^{2}(2theta13) > 10^{-4} and to the mass hierarchy for sin^{2}(2theta13) > 10^{-3}.Comment: 13 pages, 8 eps figures. Version published in PRD - experimental section with preliminary results removed, abstract and conclusions re-written accordingly, title changed, author list amended

Phylogenetic Relationships of the Decumbentes Group of Paspalum, Thrasya, and Thrasyopsis (Poaceae: Panicoideae: Paniceae)

Paspalum (Poaceae: Panicoideae: Paniceae) includes 330 species distributed mainly in tropical and subtropical regions of America. Due to the large number of species and convergence in many characters, an adequate infrageneric classification is still needed. Studies on Paniceae based on molecular and morphological data have suggested that Paspalum is paraphyletic, including the genus Thrasya, but none of these analyses have included a representative sample of these two genera. In this study, phylogenetic relationships among the informal group Decumbentes of Paspalum, plus subgenera and other informal groups, and the genera Thrasya and Thrasyopsis were estimated. A cladistic analysis under parsimony was performed using a matrix of 50 taxa and 77 morphological and anatomical characters. Different analytical parameters were explored, equally weighing characters and employing implied weights by varying the concavity constant, k, from 1 to 12. Almost all analyses showed that species of the Decumbentes group and Thrasya form a natural group, supported by the presence of axillary peduncles in the upper foliar sheath, the upper glume slightly shorter than the spikelet, margins of the lower lemma plicate on the upper anthecium, and the upper anthecium without simple papillae. The position of Thrasyopsis is not clear because it varies within the different analyses. The most important clades are discussed as well as diagnostic characters usually employed to distinguish the genera

Geographic distribution of the Gerridae in Argentina (Insect, Heteroptera)

Distributional data for the fourteen species of Gerridae known to occur in Argentina are given: Eurygerris fuscinervis (herein first recorded from San Juan and San Luis Provinces), Limnogonus (Limnogonus) aduncus (herein first recorded from Formosa Prov.), L. (L.) ignotus, L. (L.)profugus, L. (Neogerris) lubricus (herein first recorded from Cordoba Prov.), Brachymetra albinerva albinerva (herein first recorded from Salta Prov.), Rheumatobates (Rheumatobates) bonariensis, R. (R.)crassifemur crassifemur (herein first recorded from Santa Fe Prov.), Halobatopsis platensis, H. spiniventris (herein first recorded from Entre Rios Prov.), Metrobates plaumanni plaumanni, M. vigilis, Ovatametra gualeguay (herein first recorded from Buenos Aires Prov.), and Trepobates taylori (herein first recorded from Jujuy Prov.). In addition distributional maps are provided. The species characteristic for each main geographic area of Argentina are: E. fuscineruis and T. taylori for the Northwestern mountainous area; L. ignotus, L. lubricus, and R. crassifemur for the Chacoan plain; L. ignotus and H. platensis for the Bonarian plain; L. ignotus, R. bonariensis, H. platensis and 0 . gualeguay for the Mesopotamian plain. E. fuscinervis and T. taylori are restricted to mountain rivers and rivulets, whereas the remaining species seem to be genuine inhabitants of either rivulets in forested hilly areas (L. aduncus, L. profugus, B. albinerva, H. spiniventris, M. plaumanni and M. vigilis), or rivers, rivulets and ponds in plains (L. ignotus, L. lubricus, R. bonariensis, R. crassifemur, H. platensis, and 0 . gualeguay). L. ignotus is a pioneer species in lowlands, readily colonizing new pools. Excepting L. aduncus, L. profugus, and 0. gualeguay which are rare, the remaining species are common in Argentina (no enough data are available for B. albinerva, M. plaumanni, and M. vigilis). Gregariousness is high in E. fuscinervis, R. bonariensis, R. crassifemur, and H. platensis, and probably also in B. albinerva. The other species mentioned seem not to be gregarious, but 0 . gualeguay appears sometimes in the dense aggregations of H. platensis, suggesting some gregarious tendency