Papers by Jesus Nieto Martínez
Journal of Applied Polymer Science, 2009
The rheological properties of blends consisting of a long chain branched low-density polyethylene... more The rheological properties of blends consisting of a long chain branched low-density polyethylene (LDPE) and two linear low-density polyethylenes (LLDPE) are studied in detail. The weight fractions of the LDPE used in the blends are 5 and 15%. The linear viscoelastic characterization is performed at different temperatures for all the blends to check thermorheological behavior and miscibility in the melt state. Blends containing metallocene LLDPE as the matrix display thermorheologically complex behavior and show evidences of immiscibility in the melt state. The linear viscoelastic response exhibits the typical additional relaxation ascribed to the form deformation mechanism of dispersed phase droplets (LDPE). The Palierne model satisfactorily describes the behavior of these blends in the whole frequency range explored. However, those blends with Ziegler-Natta LLDPE as the matrix fulfill the time-temperature superposition, but exhibit a broad linear viscoelastic response, further than the expected for an immiscible system with a sharp interface. The rheological analysis reveals that, in addition to the droplets form relaxation, another mechanism at lower frequencies exists. The broad linear response of the blends with the Ziegler-Natta LLDPE can be explained by hypothesizing a strong interaction between the high molecular weight linear fraction of the LLDPE and the low molecular weight (almost linear) chains of the LDPE phase, forming a thick interface with its own viscoelastic properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Todos los profesionales implicados en la atención temprana del niño (pediatras, neurólogos, psiqu... more Todos los profesionales implicados en la atención temprana del niño (pediatras, neurólogos, psiquiatras, psicólogos, audiólogos, foniatras, terapeutas ocupacionales y fisioterapeutas) deberían estar suficientemente familiarizados con los signos y síntomas de autismo como para reconocer los posibles indicadores (sociales, de la comunicación y de la conducta) que hacen necesaria una evaluación diagnóstica más amplia. Es importante ser conscientes de que los niños con autismo son derivados a menudo por múltiples sospechas, tales como retrasos en el lenguaje, problemas de regulación de la conducta en la infancia, problemas motrices o sensoriales, problemas sociales y de conducta, trastornos emocionales, y problemas en el aprendizaje.
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Papers by Jesus Nieto Martínez