Sucesiones de recurrencia en la matemática recreativa

En este trabajo mostramos algunos aspectos recreativos relacionados con la sucesión de Fibonacci y otras sucesiones de recurrencia. Como aplicación didáctica, proponemos también algunos juegos y trucos basados en las propiedades de dicha sucesión.Palabras clave: Sucesión de Fibonacci; sucesiones de recurrencia; razón áurea.Recursive sequences in recreational mathematicsIn this work, some recreational aspects related to the Fibonacci sequence, as well as other recursive sequences, are shown. Moreover, in order to provide an educational application, some games and tricks based in the properties of that sequence are proposed.Keywords: Fibonacci sequence; recursive sequences; golden ratio

neuroanatomical basis of behavioral disturbances in patients with prefrontal lesions

The role of the frontal lobe in control of behavioral and cognitive abilities is explored in a group of 34 patients with brain lesions restricted to the prefrontal cortex. The scores in both structured behavioral questionnaires and standard neuropsychological tests were analyzed using the injured area of the frontal lobe as the independent variable. Our results show that patients with simultaneous lesions in supero– and inferomedial areas of the prefrontal cortex exhibit higher behavioral disturbances. Bilateral lesions also are associated with greater behavioral troubles. On the contrary, cognitive abilities are globally impaired in prefrontal patients. Results are discussed in relation to current models of the organization of the prefrontal cortex and its role on behavior control

Depercolation of aggregates upon polymer grafting in simplified industrial nanocomposites studied with dielectric spectroscopy

The dynamics of polymer and filler in simplified industrial silica-styrene-butadiene nanocomposites (silica Zeosil 1165 MP, volume fraction 0-21%v) have been studied with broadband dielectric spectroscopy (BDS) and nuclear magnetic resonance (NMR). The fraction of graftable matrix chains was varied from 0 to 100%D3. The introduction of silica nanoparticles is shown to leave the segmental relaxation unaffected, an observation confirmed by the measurement of only a thin (some Angstroms thick) immobilized layer by NMR. The low-frequency measurements are resolved in two distinct dielectric Maxwell-Wagner-Sillars (MWS) processes of different behavior with respect to changes of large-scale silica structures induced by variations of filler fraction and grafting. It is found that increasing grafting leaves the first MWS-process unaffected, while it decreases the strength of the (slower) second MWS by about a decade. At constant silica volume fraction, this indicates depercolation of the filler, thereby providing a microscopic explanation of the evolution of rheological reinforcement. The sensitivity to large-scale reorganizations together with a characterization of local polymer dynamics provides insight over many length- and time-scales into structure and dynamics of nanocomposites, and thus the physical origin of the reinforcement effect.We are thankful for a “Chercheur d'Avenir” grant by the Languedoc-Roussillon region (J.O.) and Ph.D. funding “CIFRE” by Michelin (G.P.B.). The authors acknowledge financial support from the European Commission under the Seventh Framework Program by means of the grant agreement for the Integrated Infrastructure Initiative N. 262348 European Soft Matter Infrastructure (ESMI).Peer Reviewe

Starting the area of occupational therapy in rehabilitation services "hospital el Carmen"

Demographic and epidemiological changes associated with aging population and increasing chronic diseases result in increased health demands. For this reason the State plans to open services physical medicine and rehabilitation incorporating the area of occupational therapy in the coming years.The objective of this document is to convey the experience of the implementation of the area of occupational therapy in a public hospital. Ten stages are identified throughout the implementation process and implementation, each with their facilitators and obstructionist. The main results are translated into the making of care protocols, technical documents associated with the intervention, strengthening coordination with the network of disability, occupational therapy as necessary discipline in these units, increased demand for care, the good reception of users, the importance of the work teams, and systematization document.As findings highlight the particular skills of the work team development process, coordination with network to clarify the relevance of user input, reference and counter processes. And finally, the importance of systematizing the experience that facilitates the transfer of information to teams that can run late

Quality of sleep and academic performance in high school students

Indexación: Scopus.Background: Sleeping and studying are the day-to-day activities of a teenager attending school. Aim: To determine the quality of sleep and its relationship to the academic performance among students attending morning and afternoon shifts in a public high school. Material and Methods: Students of the first and second year of high school answered an interview about socio-demographic background, academic performance, student activities and subjective sleep quality; they were evaluated using the Pittsburgh Sleep Quality Index (PSQI). Results: The interview was answered by 322 first year students aged 15 ± 5 years attending the morning shift and 364 second year students, aged 16 ± 0.5 years, attending the afternoon shift. The components: sleep latency, habitual sleep efficiency, sleep disturbance, drug use and daytime dysfunction were similar and classified as good in both school shifts. The components subjective sleep quality and duration of sleep had higher scores among students of the morning shift. The mean grades during the first semester of the students attending morning and afternoon shifts were 5.9 and 5.8, respectively (of a scale from 1 to 7). Among students of both shifts, the PSQI scale was associated inversely and significantly with academic performance. Conclusions: A bad sleep quality influences academic performance in these students.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872017000901106&lng=en&nrm=iso&tlng=e

Algoritmos de derivación y confirmación diagnóstica de citología cervical atípica: desafíos para la actualización

Indexación: ScieloEl Programa Nacional de Pesquisa y Control del Cáncer Cervicouterino de Chile ha contribuido al descenso sostenido de la mortalidad por cáncer de cuello uterino. Para la reducción de esta mortalidad ha sido fundamental la citología exfoliativa del cérvix, la que no está exenta de resultados inciertos. En este sentido, los frotis clasificados como atípicos se consideran ambiguos por la presencia de anomalías celulares de difícil determinación, lo que se traduce en un diagnóstico de probabilidad incierta. En la literatura nacional como internacional, se manifiesta un notorio interés por unificar la nomenclatura citológica cervical y los algoritmos de derivación y confirmación diagnóstica, para el manejo clínico de las mujeres con anomalías citológicas cervicales y lesiones precursoras de cáncer cervicouterino. Por lo anterior, se considera relevante los estudios que proporcionen evidencia clínica epidemiológica actualizada, que permitan optimizar el cumplimiento del Programa Nacional de Cáncer Cervicouterino, conducentes al logro de los Objetivos Sanitarios del período 2011-2020.The National Research and Control of Cervical Cancer in Chile had contributed to the sustained decline in mortality from cervical cancer. The exfoliative cytology of the cervix has been to reduce this mortality, which is not without uncertain results. The smears classified as atypical are considered ambiguous by the presence of cellular abnormalities difficult to determine, resulting in a diagnosis of uncertain probability. The literature, both nationally and internationally, is widespread interest to unify the nomenclature cervical cytology and the support of the derivation algorithms for the clinical management of women with cytologic abnormalities cervical and cervical cancer precursor lesions. Therefore, it is relevant to perform studies the provide updated epidemiological clinical evidence, to optimize the performance of the National Program for the achievement of health objectives for the period 2011-2020.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-75262012000400015&nrm=is

Massive open star clusters using the VVV survey III: A young massive cluster at the far edge of the Galactic bar

Context: Young massive clusters are key to map the Milky Way's structure, and near-IR large area sky surveys have contributed strongly to the discovery of new obscured massive stellar clusters. Aims: We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods: We physically characterized the cluster using $JHK_S$ near-infrared photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and near-infrared $K$-band spectroscopy, following the methodology presented in the first article of the series. Results: Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster members from the statistically field-star decontaminated CMD, have spectral types between O9 and B0V. According to our analysis, this young cluster ($1.0$ Myr $<$ age $< 5.0$ Myr) is located at a distance of $11^{+5}_{-6}$ kpc, and we estimate a lower limit for the cluster total mass of $(2.8^{+1.6}_{-1.4})\cdot10^3 {M}_{\odot}$. It is likely that the cluster contains even earlier and more massive stars.Comment: Accepted for publication as a Letter in A&

New galactic star clusters discovered in the VVV survey : Candidates projected on the inner disk and bulge

Context. VISTA Variables in the Vía Láctea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy. Aims. The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge. Methods. Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JHKS color images to select new cluster candidates on the basis of apparent overdensities. DR1, DR2, CASU, and point spread function photometry of 10 × 10 arcmin fields centered on each candidate cluster were used to construct color-magnitude and color-color diagrams. Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their nature. Results. We report the discovery of 58 new infrared cluster candidates. Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters.Peer reviewedFinal Accepted Versio

Network dynamics in nanofilled polymers

It is well accepted that adding nanoparticles (NPs) to polymer melts can result in significant property improvements. Here we focus on the causes of mechanical reinforcement and present rheological measurements on favourably interacting mixtures of spherical silica NPs and poly(2-vinylpyridine), complemented by several dynamic and structural probes. While the system dynamics are polymer-like with increased friction for low silica loadings, they turn network-like when the mean face-to-face separation between NPs becomes smaller than the entanglement tube diameter. Gel-like dynamics with a Williams-Landel-Ferry temperature dependence then result. This dependence turns particle dominated, that is, Arrhenius-like, when the silica loading increases to similar to 31 vol%, namely, when the average nearest distance between NP faces becomes comparable to the polymer's Kuhn length. Our results demonstrate that the flow properties of nanocomposites are complex and can be tuned via changes in filler loading, that is, the character of polymer bridges which 'tie' NPs together into a network.We thank Leon Serc (ETH Zurich) for help with FTIR. Enlightening discussions with Ulrich Jonas are gratefully acknowledged. Partial support has been provided by the EU FP7 (ETN Supolen GA-607937, Infrastructure ESMI GA-262348) and the Greek General Secretariat for Research and Technology (Thalis-380238 COVISCO). M.R. acknowledges financial support from the National Science Foundation under grants DMR-1309892, DMR-1436201 and DMR-1121107, the National Institutes of Health under grants P01-HL108808 and 1UH2HL123645 and the Cystic Fibrosis Foundation. D.Z., S.G., R.H.C. and S.K.K. gratefully acknowledge the National Science Foundation grant DMR-1408323 for financial support

Association of sociocultural stressors with bipolar disorder onset in Puerto Rican youth growing up as members of a minoritized ethnic group: results from the Boricua Youth Longitudinal Study

BACKGROUND: The development of bipolar disorder is currently explained by a complex interaction of genetic and environmental factors. Less is known regarding the influence of sociocultural factors. This study aims to evaluate the incidence and impact of sociocultural factors on bipolar disorder onset in two comparable samples of youth growing up in different social settings. METHODS: We leveraged data from two urban population-based cohorts representative of Puerto Rican children growing up in either San Juan (Puerto Rico) or the South Bronx (NYC) and followed up for 17 years. Bipolar disorder diagnoses were based on retrospective self-reports on the World Health Organization Composite International Diagnostic Interview. We used a causal inference approach to estimate associations of sociocultural factors with bipolar disorder onset after adjusting for potential confounders. FINDINGS: We found that South Bronx children, who grew up as a minoritized group, had twice the risk of bipolar disorder onset as young adults, with an incidence rate of 2.22 new cases per 1000 person-years compared to 1.08 new cases in San Juan (incidence rate difference, 1.13; 95% CI, 0.09-1.20). After adjusting for potential confounders, South Bronx children had the same lifetime hazard of bipolar disorder onset compared to San Juan children. However, our analysis demonstrated that caregivers' exposure to societal cultural stress partially explained the increased risk of bipolar disorder onset in the South Bronx, in addition to the potential contribution of genetics. INTERPRETATION: Our results provide evidence that societal cultural stress can increase the risk of lifetime bipolar disorder onset in youth growing up as a minoritized group. Addressing stress in minoritized groups might reduce the risk of bipolar disorder onset. FUNDING: The Boricua Youth Study has been supported by the National Institutes of HealthMH56401, MH098374, DA033172, and AA020191. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the article