Functionalization, compatibilization and properties of polyolefin composites with natural fibers

The article is focused on analyzing the effect of functionalization and reactive processing on the morphological, thermal, rheological and mechanical properties of composites of isotactic polypropylene (PP), polystyrene (PS), poly(ethylene-vinyl acetate) (EVA), with cellulose fibers, hemp or oat as natural fillers. Both polymers and fibers were modified with bi-functional monomers (glycidyl methacrylate, GMA; maleic anhydride, MA) capable of facilitating chemical reactions between the components during melt mixing. Polyolefin copolymers containing reactive groups (PP-g-GMA, SEBS-g-MA, PS-co-MA, etc.) were used as compatibilizers. Optical and SEM microscopy, FTIR, RX, DSC, TGA, DMTA, rheological and mechanical tests were employed for the composites characterization. The properties of binary and ternary systems have been analyzed as a function of both fiber and compatibilizer content. All compatibilized systems showed enhanced fiber dispersion and interfacial adhesion. The phase behavior and the thermal stability of the composites were affected by the chemical modification of the fibers. Marked changes in the overall crystallization processes and crystal morphology of PP composites were observed owing to the nucleating effect of the fibers. The tensile mechanical behavior of the compatibilized composites generally resulted in a higher stiffness, depending on the fiber amount and the structure and concentration of compatibilizer.Fil: Pracella, Mariano. Institute of Composite and Biomedical Materials; ItaliaFil: Minhaz-Ul Haque, M.. Universita Degli Studi Di Pisa; ItaliaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Ontogenetic changes in DNA and RNA content of laboratory-reared Prochilodus lineatus larvae: use of RNA/DNA ratios as indicators of nutritional condition

The aims of the present study were to describe the ontogenetic performance of DNA and RNA content, as well as to assess the nutritional condition of Prochilodus lineatus larvae reared under different feeding treatments. The experiment consisted of two parts, the first 6-14 days after hatching (DAH) and the second 15-21 DAH. In the first part of the experiment, larvae were kept under one of two feeding treatments: fed or starved. During the second part of the experiment, larvae were kept under one of four treatments: fed, fed until 14 DAH and later starved, starved until 14 DAH and fed later or starved. It is of note that the size and weight reached of larvae that were starved during early development and later received food were higher than those of than larvae in the other feeding treatments. In addition, instantaneous growth rates were higher and nutritional condition was better in larvae that were initially starved and fed later. The availability of food following a period of starvation seems to trigger larval metabolism and cellular division. Consequently, we recommend maintaining appropriate food provision in the aquaculture of P. lineatus larvae, especially in advanced developmental stages. We verified that RNA/DNA ratio is affected by the feeding condition and that it is sensitive enough to promptly reflect changes in feeding conditions of P. lineatus larvae. Thus, the RNA/DNA ratio could be used to assess nutritional condition of both wild and cultured P. lineatus larvae.Fil: Diaz, Marina Vera. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Gómez, M. I.. Dirección de Pesca Continental; ArgentinaFil: Sánchez, S.. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: Fuentes, Carlos Mariano. Dirección de Pesca Continental; Argentin

Breaks in Presence in Virtual Environments: An Analysis of Blood Flow Velocity Responses

One of the techniques used to monitor variations in presence during a virtual reality experience is the analysis of breaks in presence (BIPs). Previous studies have monitored peripheral physiological responses during BIPs in order to find a characteristic physiological response. In this work, blood flow velocity (BFV) in middle cerebral arteries (MCAs) has been monitored using transcranial Doppler ultrasound during the exposure to a virtual environment. Two BIPs of different intensity were forced during the virtual reality experience. Variations in BFV during each BIP and during the recovery periods that followed them have been analyzed. A decreasing trend was observed in BFV signal during the most intense BIP in most subjects. However, during the less intense BIP an oscillating behavior was observed. Significant differences have been found between the maximum percentage variations observed in each BIP. During the recovery periods, an increasing trend was observed. The mean response times (time elapsed since the beginning of the period until the maximum percentage variation in the period occured) ranged between 10.116 s and 12.774 s during the BIPs, and between 11.025 s and 13.345 during the recovery periods, depending on the vessel and on the kind of BIP. © 2011 by the Massachusetts Institute of Technology.Rey Solaz, B.; Parkhutik, V.; Tembl, J.; Alcañiz Raya, ML. (2011). Breaks in Presence in Virtual Environments: An Analysis of Blood Flow Velocity Responses. Presence: Teleoperators and Virtual Environments. 20(3):273-286. doi:10.1162/PRES_a_00049S27328620

Seasonal cycle of precipitation variability in South America on intraseasonal timescales

The seasonal cycle of the intraseasonal (IS) variability of precipitation in South America is described through the analysis of bandpass filtered outgoing longwave radiation (OLR) anomalies. The analysis is discriminated between short (10--30 days) and long (30--90 days) intraseasonal timescales. The seasonal cycle of the 30--90-day IS variability can be well described by the activity of first leading pattern (EOF1) computed separately for the wet season (October--April) and the dry season (May--September). In agreement with previous works, the EOF1 spatial distribution during the wet season is that of a dipole with centers of actions in the South Atlantic Convergence Zone (SACZ) and southeastern South America (SESA), while during the dry season, only the last center is discernible. In both seasons, the pattern is highly influenced by the activity of the Madden--Julian Oscillation (MJO). Moreover, EOF1 is related with a tropical zonal-wavenumber-1 structure superposed with coherent wave trains extended along the South Pacific during the wet season, while during the dry season the wavenumber-1 structure is not observed. The 10--30-day IS variability of OLR in South America can be well represented by the activity of the EOF1 computed through considering all seasons together, a dipole but with the stronger center located over SESA. While the convection activity at the tropical band does not seem to influence its activity, there are evidences that the atmospheric variability at subtropical-extratropical regions might have a role. Subpolar wavetrains are observed in the Pacific throughout the year and less intense during DJF, while a path of wave energy dispersion along a subtropical wavetrain also characterizes the other seasons. Further work is needed to identify the sources of the 10--30-day-IS variability in South America

Análisis e implementación de ciudades inteligentes

En la actualidad la tecnología es parte de la vida cotidiana de las personas tanto para trabajo, comunicaciones, esparcimiento; las empresas invierten y desarrollan servicios tecnológicos que les facilitan la vida a las personas mientras consumen sus productos y servicios. Hoy en día es común tener aplicaciones en el smartphone para pedir un vehículo para traslado, solicitar comida a domicilio y un sinfín de otras cosas. Los gobiernos no pueden escapar a esta tendencia y deben actualizarse, hacer uso de la tecnología existente, diseñar recursos y servicios para facilitar las gestiones de sus ciudadanos a la vez que brinda mayor transparencia a sus acciones. Es por eso que surge el concepto de cuidades inteligentes o Smart Cities donde la tecnología se hace presente. Este proyecto de investigación se basa en el estudio de las Smart Cities (sus bases, fundamentos, grado de implementación) con el objetivo de realizar propuestas para facilitar y mejorar la implementación de las mismas.Red de Universidades con Carreras en Informátic

Submesoscale dispersion in the vicinity of the Deepwater Horizon spill

Reliable forecasts for the dispersion of oceanic contamination are important for coastal ecosystems, society and the economy as evidenced by the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 and the Fukushima nuclear plant incident in the Pacific Ocean in 2011. Accurate prediction of pollutant pathways and concentrations at the ocean surface requires understanding ocean dynamics over a broad range of spatial scales. Fundamental questions concerning the structure of the velocity field at the submesoscales (100 meters to tens of kilometers, hours to days) remain unresolved due to a lack of synoptic measurements at these scales. \textcolor{black} {Using high-frequency position data provided by the near-simultaneous release of hundreds of accurately tracked surface drifters, we study the structure of submesoscale surface velocity fluctuations in the Northern Gulf Mexico. Observed two-point statistics confirm the accuracy of classic turbulence scaling laws at 200m$-$50km scales and clearly indicate that dispersion at the submesoscales is \textit{local}, driven predominantly by energetic submesoscale fluctuations.} The results demonstrate the feasibility and utility of deploying large clusters of drifting instruments to provide synoptic observations of spatial variability of the ocean surface velocity field. Our findings allow quantification of the submesoscale-driven dispersion missing in current operational circulation models and satellite altimeter-derived velocity fields.Comment: 9 pages, 6 figure

Relationship between Resilience and Self-regulation: A Study of Spanish Youth at Risk of Social Exclusion

The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fpsyg.2017.00612/full#supplementary-materialThe ability to self-regulate behavior is one of the most important protective factors in relation with resilience and should be fostered especially in at-risk youth. Previous research has characterized these students as having behaviors indicating lack of foresight. The aim of the present study was to test the hypothetical relationship between these personal variables. It was hypothesized that self-regulation would be associated with and would be a good predictor of resilience, and that low-medium-high levels of self-regulation would lead to similar levels of resilience. The participants were 365 students -aged 15 and 21- from Navarre (Spain) who were enrolled in Initial Vocational Qualification Programs (IVQP). For the assessment, the Connor Davidson Resilience Scale (CD-RISC) and the Short Self-Regulation Questionnaire (SSRQ) were applied. We carried out linear association analyses (correlational and structural) and non-linear interdependence analyses (MANOVA) between the two constructs. Relationships between them were significant and positive. Learning from mistakes (self-regulation) was a significant predictor of coping and confidence, tenacity and adaptation, and tolerance to negative situations (resilience). Likewise, low-medium-high levels of self-regulation correlated with scores on resilience factors. Implications of these results for educational practice and for future research are discussed.Motivational-affective strategies of personal self-regulation and coping with stress in the university teaching-learning process. Ref. EDU2011-24805 (2012-2015). Ministry of Economy and Competitiveness (Spain) and FEDER Found (EU)

The nanomechanics of neurotoxina proteins reveals common features at the start of the neurodegeneration cascade.

1 pags. -- 56th Annual Meeting of the Biophysical-Society, FEB 25-29, 2012, San Diego, CAAmyloidogenic neurodegenerative diseases are incurable conditions caused by specific largely disordered proteins. However, the underlying molecular mechanism remains elusive. A favored hypothesis postulates that a critical conformational change in the monomer (an ideal therapeutic target) in these ‘‘neurotoxic proteins’’ triggers the pathogenic cascade. Using force spectroscopy with unequivocal singlemolecule identification we demonstrate a rich conformational polymorphism at their monomer level. This polymorphism strongly correlates with amyloidogenesis and neurotoxicity: it is absent in a fibrillization-incompetent mutant, favored by familial-disease mutations and diminished by a surprisingly promiscuous inhibitor of the monomeric b-conformational change and neurodegeneration. The demonstrated ability to inhibit the conformational heterogeneity of these proteins by a single pharmacological agent reveals common features in the monomer and suggests a common pathway to diagnose, prevent, halt or reverse multiple neurodegenerative disease

Empleo de aprendizaje basado en juegos y técnicas de gamificación en el ámbito universitario

El aprendizaje basado en juegos puede ser utilizado también en el ámbito académico universitario, teniendo como enfoque principal la motivación de los alumnos. Pero también implica analizar cómo presentar los contenidos para que los alumnos puedan evaluar sus conocimientos por fuera del espacio del aula física. Por otra parte el concepto de gamificación plantea utilizar técnicas de juegos en ámbitos no lúdicos, lo que implica analizar mecanismos de implementación de desafíos, premios, niveles alcanzados, etc El desafío radica en cómo aplicar esos mecanismos en el ámbito universitario. Esta línea de I+D (Investigación y Desarrollo) se centra en el análisis de técnicas de gamificación y aprendizaje basado en juegos; junto con la construcción de un software que podrá ser accesible desde internet, utilizándolo tanto en computadoras como dispositivos móviles y promueva de forma entretenida un apoyo a la construcción del conocimiento.Eje: Tecnología Informática Aplicada en EducaciónRed de Universidades con Carreras en Informática (RedUNCI