This work presents the deconvolution of thermoluminescent (TL) glow curves, by using logistic asymmetric functions, of sintered pure alumina matrices under two different conditions: 1000 °C/3h (NALO) and 1000 °C/6h (ALO), and also, of cerium-doped matrix with 0.1 wt.% sintered at 1000 °C/3h (NALOCe0.1). Sintering treatments induced a remarkable change in the TL kinetics and consequently in the glow curve shape, in terms of the number of traps and initially trapped charge carriers. Structural analysis revealed α-alumina phase in NALO and ALO matrices, and its distortion for NALOCe0.1, achieving a generation of new electronic traps energetically more stable for doped matrix. This result offers a possible solution in order to reduce the notable fading for TL characteristic peak in alumina matrix, expanding its field of applications.

J. F. Montoyaa, *, E. A. Chavarriagab, **, S. Villada-Gilc, ***, O. D. Gutierrezd, and O. Restrepoe aGrupo GAMA, Corporación Universitaria Lasallista, Caldas, Colombia bDepartamento de Ciencias Básicas, Universidad Católica Luis Amigó, Medellín, Colombia cFacultad de Ciencias Básicas, Sociales y Humanas, Politécnico Colombiano Jaime Isaza Cadavid, Medellín, Colombia dInstituto Tecnológico Metropolitano, Medellín, Colombia eGrupo del Cemento y Materiales de Construcción. Universidad Nacional de Colombia sede Medellín, Medellín, Colombia *e-mail: jumontoya@lasallistadocentes.edu.co **e-mail: eachavar@unal.edu.co ***e-mail: svillada@elpoli.edu.co Received June 20, 2020; revised August 21, 2020; accepted August 24, 2020

The biodiversity and productivity of the Amazon floodplain depend on nutrients and organic matter transported with suspended sediments. Nevertheless, there are still fundamental unknowns about how hydrological and rainfall variability influence sediment flux in the Amazon River. To address this gap, we analyzed 3069 sediment samples collected every 10 days during 1995–2014 at five gauging stations located in the main rivers. We have two distinct fractions of suspended sediments, fine (clay and silt) and coarse (sand), which followed contrasting seasonal and long-term patterns. By taking these dynamics into account, it was estimated, for first time, in the Amazon plain, that the suspended sediment flux separately measured approximately 60% fine and 40% coarse sediment. We find that the fine suspended sediments flux is linked to rainfall and higher coarse suspended sediment flux is related with discharge. Additionally this work presents the time lag between rainfall and discharge, which is related to the upstream area of the gauging. This result is an important contribution to knowledge of biological and geomorphological issues in Amazon basin.

The incorporation of nanoparticles inside polymeric matrices has led to the development of multifunctional composites necessary to repair human tissues. The addition of nanoparticles may improve the properties of the composite materials such as surface area, mechanical properties, flexibility, hydrophilicity, electrical conductivity, etc. These properties can help in cellular growth, proliferation and/or differentiation. In this work, scaffolds of polycaprolactone (PCL) and reduced graphite oxide (rGO) were built by electrospinning technique. The ratios of rGO/PCL employed were 0.25, 0.5, 0.75 and 1 wt%. Two different voltage setup (10 and 15 kV) and distance of 10 cm were used for electrospinning. Thermal, mechanical, morphological, electrical, porosity and absorption water tests were made to the scaffolds. Samples electrospun at 10 kV with rGO showed improvement in mechanical properties with an increase of 190% of Young's Modulus in comparison with sample without rGO. Furthermore, samples electrospun at 15 kV showed an important deterioration with the addition of rGO but had an increase in the electrical conductivity and porosity. Overall, the addition of 0.75 and 1 wt% of rGO led to a detriment on properties due to formation of aggregates. The voltage on the electrospinning process plays a very important role in the final properties of the nanocomposites scaffolds of PCL-rGO.

This study compares specific acceptance-based strategies and cognitive-control-based strategies for coping with experimentally induced pain. Forty participants were randomly assigned to an acceptance-based protocol (ACT), the goal of which was to disconnect pain-related thoughts and feelings from literal actions, or to a control-based protocol (CONT) that focused on changing or controlling pain-related thoughts and feelings. Participants took part in a nonsense-syllables-matching task that involved successive exposures to increasingly painful shocks. In both conditions, the task involved an overall value-oriented context that encouraged the participants to continue with the task despite the exposure to pain. At times throughout the task, participants were asked to choose to continue with the task and be shocked or stop the task and avoid being shocked. Each choice had specific costs and benefits. Participants performed the task twice, both before and after receiving the assigned experimental protocol. Two measures were obtained at pre- and post-intervention: tolerance of the shocks and self-reports of pain. ACT participants showed significantly higher tolerance to pain and lower believability of experienced pain compared to the CONT condition. Conceptual and clinical implications are discussed.