Herramienta de análisis y visualización de noticias basada en Machine Learning aplicado a Redes Sociales

La cantidad de información que generan las sociedades modernas está en continuo crecimiento. Cuando ocurre un suceso relevante se produce una saturación de noticias de prensa. Esto, sumado a la tendencia de las redes sociales y los buscadores a producir burbujas informativas, puede provocar desinformación. Hace años que la prensa escrita tradicional ha dado paso a un conglomerado de periódicos online, blogs, redes sociales y agregadores de noticias. Actualmente un número creciente de personas accede a las noticias a través de redes sociales como Twitter, Facebook, Whatsapp; o de buscadores como Google y Bing. Estas herramientas ayudan a bucear en el mar de información para encontrar noticias relevantes, pero también pueden introducir sesgos que limitan la exposición a noticias de posiciones contrarias. En este trabajo se han analizado tres casos de noticias de gran impacto, que han provocado un elevado número de publicaciones en redes sociales. Para realizar dicho análisis, se ha desarrollado una herramienta que permite visualizar el impacto de las noticias de prensa en las redes sociales, e identificar grupos de noticias de ideología similar según la percepción de los usuarios de Twitter. La herramienta construida permite recolectar un elevado número de tweets relacionados con un suceso de interés, para formar a partir de ellos un grafo de noticias. Posteriormente la herramienta analiza el grafo con diversos algoritmos de detección de comunidades, y ofrece al usuario una visualización interactiva. Una vez construida la herramienta, se realizaron tres pruebas con diferentes sucesos informativos y usuarios, para evaluar la calidad de los resultados. El resultado final del trabajo es una herramienta que permite analizar un elevado número de tweets de forma automatizada y proporciona una visualización en forma de grafo que ayuda a identificar las noticias más importantes y los principales grupos de opinión

Molecular etiological profile of atypical bacterial pathogens, viruses and coinfections among infants and children with community acquired pneumonia admitted to a national hospital in Lima, Peru

Objective The main objective of this study was to detect the presence of 14 respiratory viruses and atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae), via polymerase chain reaction in patients under 18 years old hospitalized due to community-acquired pneumonia (CAP) from Lima, Peru. Results Atypical pathogens were detected in 40% (58/146); viral etiologies in 36% (52/146) and coinfections in 19% (27/146). The most common etiological agent was M. pneumoniae (n = 47), followed by C. pneumoniae (n = 11). The most frequent respiratory viruses detected were: respiratory syncytial virus A (n = 35), influenza virus C (n = 21) and parainfluenza virus (n = 10). Viral-bacterial and bacterium-bacterium coinfections were found in 27 cases. In our study population, atypical bacteria (40%) were detected as frequently as respiratory viruses (36%). The presence of M. pneumoniae and C. pneumoniae should not be underestimated as they can be commonly isolated in Peruvian children with CAP.Peer ReviewedPostprint (published version

Dengue diagnosis in an endemic area of Peru: Clinical characteristics and positive frequencies by RT-PCR and serology for NS1, IgM, and IgG

Background: Huánuco is a central eastern region of Peru whose geography includes high forest and low jungle, as well as a mountain range that constitutes the inter-Andean valleys. It is considered a region endemic for dengue due to the many favorable conditions that facilitate transmission of the virus. Methods: A total of 268 serum samples from patients in Huánuco, Peru with an acute febrile illness were assessed for the presence of dengue virus (DENV) via RT-PCR and NS1, IgM, and IgG ELISA during December 2015 and March 2016. Results: DENV was detected in 25% of samples via RT-PCR, 19% of samples by NS1 antigen ELISA, and 10.5% of samples by IgM ELISA. DENV IgG was detected in 15.7% of samples by ELISA. The most frequent symptoms associated with fever across all groups were headache, myalgia, and arthralgia, with no significant difference between the four test methods Conclusions: In this study, DENV was identified in up to 25% of the samples using the standard laboratory method. In addition, a correlation was established between the frequency of positive results and the serological tests that determine NS1, IgM, and IgG. There is an increasing need for point-of-care tests to strengthen epidemiological surveillance in Peru.Peer ReviewedPostprint (published version

Emerging and reemerging arboviruses: a new threat in Eastern Peru

Background: Arboviral diseases are one of the most common causes of acute febrile illness (AFI) and a significant health problem in South America. In Peru, laboratory etiologic identification of these infections occurs in less than 50% of cases, leading to underdiagnoses of important emerging arboviruses. Aim: To assess the prevalence of the Dengue (DENV), Oropouche (OROV), Chikungunya (CHIKV), Mayaro (MAYV) and Zika (ZIKV) viruses in patients with acute febrile illness from Puerto Maldonado (Peru). Methodology: Serum samples were obtained from patients with AFI during January 2016 to March 2016. A total of 139 specimens were analyzed for the presence of DENV, OROV, CHIKV, MAYV, and ZIKV using polymerase chain reaction (PCR). Results: CHIKV in 9.4% and OROV in 8.6% were the most prevalent arboviruses, followed by DENV and ZIKV, with a prevalence of 6.5% and 5%, respectively. Among all patients, the most common symptoms accompanying fever were headaches 79.9%, muscle pain 65.5% and joint pain 63.3%. Conclusions: During this short 3-month period, 4 arboviruses were detected by PCR, CHIKV and OROV being the most common arboviruses in Puerto Maldonado (Peru). Thus, it is crucial to include OROV detection in the national health surveillance. Furthermore, the etiologic clinical diagnosis of arboviral infections is not possible due to the low specificity of symptoms; therefore an increase of cases confirmed by molecular diagnostic methods will enhance arboviral surveillance in Peru.Peer ReviewedPostprint (published version

A caloritronics-based Mott neuristor

Machine learning imitates the basic features of biological neural networks to efficiently perform tasks such as pattern recognition. This has been mostly achieved at a software level, and a strong effort is currently being made to mimic neurons and synapses with hardware components, an approach known as neuromorphic computing. CMOS-based circuits have been used for this purpose, but they are non-scalable, limiting the device density and motivating the search for neuromorphic materials. While recent advances in resistive switching have provided a path to emulate synapses at the 10 nm scale, a scalable neuron analogue is yet to be found. Here, we show how heat transfer can be utilized to mimic neuron functionalities in Mott nanodevices. We use the Joule heating created by current spikes to trigger the insulator-to-metal transition in a biased VO2 nanogap. We show that thermal dynamics allow the implementation of the basic neuron functionalities: activity, leaky integrate-and-fire, volatility and rate coding. By using local temperature as the internal variable, we avoid the need of external capacitors, which reduces neuristor size by several orders of magnitude. This approach could enable neuromorphic hardware to take full advantage of the rapid advances in memristive synapses, allowing for much denser and complex neural networks. More generally, we show that heat dissipation is not always an undesirable effect: it can perform computing tasks if properly engineered

Niveles de resistencia a quinolonas y otros antimicrobianos en cepas de Escherichia coli comensales en niños de la zona periurbana de Lima, Perú

El objetivo principal del estudio fue establecer el nivel de resistencia a antimicrobianos en un total de 222 cepas comensales de E. coli de origen fecal, en Perú. Las frecuencias de resistencia encontrados, frente los antimicrobianos evaluados, fueron: ampicilina (62,6%), cotrimoxazol (48,6%), tetraciclina (43,0%) y cloranfenicol (15,8%). Destacan los elevados niveles de resistencia a quinolonas: 32% al ácido nalidíxico (NAL) y 12% a ciprofloxacino (CIP). Estos elevados niveles hacia las quinolonas en cepas comensales aisladas en niños de esta franja de edad, realzan el uso extendido y el impacto de consumo de este tipo de antimicrobianos en la comunidad, mostrando el riesgo potencial de su pérdida de utilidad en el áreaPostprint (published version

Smart systems related to polypeptide sequences

Increasing interest for the application of polypeptide-based smart systems in the biomedical field has developed due to the advantages given by the peptidic sequence. This is due to characteristics of these systems, which include: biocompatibility, potential control of degradation, capability to provide a rich repertoire of biologically specific interactions, feasibility to self-assemble, possibility to combine different functionalities, and capability to give an environmentally responsive behavior. Recently, applications concerning the development of these systems are receiving greater attention since a targeted and programmable release of drugs (e.g. anti-cancer agents) can be achieved. Block copolymers are discussed due to their capability to render differently assembled architectures. Hybrid systems based on silica nanoparticles are also discussed. In both cases, the selected systems must be able to undergo fast changes in properties like solubility, shape, and dissociation or swelling capabilities. This review is structured in different chapters which explain the most recent advances on smart systems depending on the stimuli to which they are sensitive. Amphiphilic block copolymers based on polyanionic or polycationic peptides are, for example, typically employed for obtaining pH-responsive systems. Elastin-like polypeptides are usually used as thermoresponsive polymers, but performance can be increased by using techniques which utilize layer-by-layer electrostatic self-assembly. This approach offers a great potential to create multilayered systems, including nanocapsules, with different functionality. Recent strategies developed to get redox-, magnetic-, ultrasound-, enzyme-, light-and electric-responsive systems are extensively discussed. Finally, some indications concerning the possibilities of multi-responsive systems are discussed.Postprint (published version

El estiaje del Ebro durante el verano de 2002. Causas climáticas y consecuencias sobre la calidad del agua en el tramo Zaragoza - Escatrón

Ponencia presentada en: IV Congreso de la Asociación Española de Climatología "El Clima entre el Mar y la Montaña", celebrado en Santander del 2 al 5 de noviembre de 2004.[ES]Esta comunicación muestra datos climáticos que explican el intenso estiaje del Ebro durante el verano de 2002 en su tramo medio y analiza las principales consecuencias sobre la calidad del agua y del ecosistema fluvial en el tramo Zaragoza - Escatrón.[EN]This text shows climatic data which explain the intense low water in Ebro river during summer 2002 along its middle section and analizases the main consequences on water quality and the fluvial ecosistem in the sector from Zaragoza to Escatrón

Nanoperforations in poly(lactic acid) free-standing nanomembranes to promote interactions with cell filopodia

Nanoperforated poly(lactic acid) (PLA) free-standing nanomembranes (FsNMs) have been prepared using a two-step process: (1) spin-coating a mixture of immiscible polymers to provoke phase segregation and formation of appropriated nanofeatures (i.e. phase separation domains with dimensions similar to the entire film thickness); and (2) selective solvent etching to transform such nanofeatures into nanoperforations. For this purpose, PLA has been mixed with polyethylene glycol (PEG) and poly(vinyl alcohol) (PVA). Unfortunately, the characteristics of PLA:PEG mixtures were not appropriated to prepare nanoperforated FsNMs. In contrast, perforated PLA FsNMs with pores crossing the entire film thickness, which have been characterized by scanning electron microscopy and atomic force microscopy, were obtained using PLA:PVA mixtures. The diameter (¿) of such pores has been controlled through both the PLA:PVA ratio and the processing conditions of the mixtures, FsNMs with pores of ¿ ˜ 0.8 µm, 170 nm and 65 nm being achieved. Investigations on nanoperforated FsNMs (i.e. those with ¿ ˜ 170 and 65 nm), which are the more regular, reveal that pores crossing the entire membrane thickness do not affect the surface wettability of PLA but drastically enhances the cellular response of this biomaterial. Thus, cell proliferation assays indicate that cell viability in PLA with perforations of ¿ ˜ 170 nm is ~2.6 and ~2.2 higher than in non-perforated PLA and PLA with perforations of ¿ ˜ 65 nm, respectively. This excellent response has been attributed to the similarity between the nanoperforations with ¿ ˜ 170 nm and the filopodia filaments in cells (¿ ˜ 100–200 nm), which play a crucial role in cell migration processes. The favorable interaction between the perforated membrane nanofeatures and cell filopodia has been corroborated by optical and scanning electron microscopies.Peer ReviewedPostprint (author's final draft

Contribution of Time of Drinking Onset and Family History of Alcohol Problems in Alcohol and Drug Use Behaviors in Argentinean College Students

Aims: The aim of the study was to analyze independent and potential interactive effects of age at drinking onset and family history of alcohol abuse on subsequent patterns of alcohol drinking, alcohol-related problems and substance use. Methods: Participants were college students (60.3% females, mean age = 20.27 ± 2.54 years) from the city of Córdoba, Argentina. Several measures were used to assess alcohol, tobacco and drug use. The Spanish version of the Brief Young Adult Alcohol Consequences Questionnaire was used to assess alcohol-related problems. Factorial analyses of variance, or its non-parametric equivalent, were performed to explore differences in substance use behaviors and alcohol-related problems in subjects with early or late drinking onset and with or without family history of alcohol abuse. Chi-square tests were conducted to analyze the association between these two risk factors and categorical measures of alcohol, tobacco and drug use. Results: Early onset of drinking was associated with amount of consumption of alcohol including up to hazardous levels, as well as tobacco and drug use. However, the frequency of alcohol problems and frequency of episodes of alcohol intoxication were only related to age of onset in those with a positive family history of alcohol problems. Conclusion: Delaying drinking debut is particularly important in the prevention of future alcohol problems in those adolescents who have a family history of such problems.Fil: Pilatti, Angelina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Caneto, Florencia. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Garimaldi, Javier Alejandro. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Vera, Belén del Valle. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin