Analytical approach to soliton ratchets in asymmetric potentials

We use soliton perturbation theory and collective coordinate ansatz to investigate the mechanism of soliton ratchets in a driven and damped asymmetric double sine-Gordon equation. We show that, at the second order of the perturbation scheme, the soliton internal vibrations can couple {\it effectively}, in presence of damping, to the motion of the center of mass, giving rise to transport. An analytical expression for the mean velocity of the soliton is derived. The results of our analysis confirm the internal mode mechanism of soliton ratchets proposed in [Phys. Rev. E {\bf 65} 025602(R) (2002)].Comment: 9 figures. Submitted to Phys. Rev.

Eco-friendly performance as a determining factor of the Adoption of Virtual Reality Applications in National Parks

The purpose of this study is to find the key factors of influence for the use and acceptance of Virtual Reality (VR) by tourists visiting National Parks in Costa Rica. The aim is to find whether tourists are willing to use VR to contribute to the eco-friendly performance of the area they visit and to determine whether they are willing to use VR in environmental tourism to protect flora and fauna. This study is quantitative and uses the theoretical Unified Theory of Acceptance and Use of Technology (UTAUT) Model and a survey as the research instrument to obtain data. Data analysis was carried out using a PLS-SEM statistical analysis. The data collection procedure consisted of 50 people being surveyed in the initial pre-test phase and later 455 tourists in the fieldwork phase with national or foreign people over the age of 18 who visit or have visited the national parks of Costa Rica. The results show that there is a positive relationship between eco-friendly performance and the intention to use VR technology, as well as the actual use of VR for the benefit of the environment. The UTAUT2 model was used to find the effect of eco-friendly performance on the intention to use VR, as well as the use of this technology during visits to tourist destinations. The originality of the work is in answering the question of how to develop sustainable tourism in Costa Rica with the use of VR devices and applications that also allow the conservation of flora and fauna.2021-2

Degradation and adsorption of AZO RR239 dye in aqueous solution by nanoscale zerovalent iron particles immobilized on sawdust

ABSTRACT: Carra sawdust pretrated with formaldehyde was used to adsorb RR239 (reactive azo dye) at varying pH and zerovalent iron (ZVI) dosage. Modeling of kinetic results shows that sorption process is best described by the pseudosecond-order model. Batch experiments suggest that the decolorization efficiency was strongly enhanced with the presence of ZVI and low solution pH. The kinetics of dye sorption by mixed sorbent (5 g of sawdust and 180 mg of ZVI) at pH 2.0 was rapid, reaching more than 90% of the total discoloration in three minutes.RESUMEN: Se reportan resultados de adsorción del colorante RR239 (colorante reactivoazo) con aserrín pretratado con formaldehído, los experimentos se realizaron a dos valores de pH y considerando el efecto de nanopartículas de hierro de valencia cero. Los datos cinéticos de adsorción se ajustaron bien a un modelo de seudo segundo orden. Los experimentos realizados en el sistema por lotes sugieren que la eficiencia de la decoloración esta fuertemente influenciada por la presencia de partículas de ZVI y bajos pH. La cinética de adsorción por la mezcla de adsorbente (5 g de aserrín y 180 mg de ZVI) a pH 2,0 fue rápida, lográndose más del 90% de la decoloración en 3 minutos

Directrices para zonificación, uso y manejo del desierto La Tatacoa

El Desierto de la Tatacoa se caracteriza por sus condiciones climáticas y botánicas de zonas tropicales áridas y semiáridas, cuyas tierras están dedicadas principalmente a la ganadería extensiva y en menor proporción a la agricultura. Sin embargo, sobresale por su riqueza paleontológica y sus áreas de refugio para la diversidad de aves en el alto Magdalena,  los atractivos naturales y aspectos sugerentes para el ecoturismo; éstos no son protegidos adecuadamente y en consecuencia, se ha considerado necesario proponer algunas directrices para su zonificación con fines de uso y manejo

Fasting enhances pyroglutamyl peptidase II activity in tanycytes of the mediobasal hypothalamus of male adult rats

Fasting down-regulates the hypothalamus-pituitary-thyroid (HPT) axis activity through a reduction of TRH synthesis in neurons of the parvocellular paraventricular nucleus of the hypothalamus (PVN). These TRH neurons project to the median eminence (ME), where TRH terminals are close to the cytoplasmic extensions of β2 tanycytes. Tanycytes express pyroglutamyl peptidase II (PPII), the TRH-degrading ectoenzyme that controls the amount of TRH that reaches the anterior pituitary. We tested the hypothesis that regulation of ME PPII activity is another mechanism by which fasting affects the activity of the HPT axis. Semiquantitative in situ hybridization histochemistry data indicated that PPII and deiodinase 2 mRNA levels increased in tanycytes after 48 hours of fasting. This increase was transitory, followed by an increase of PPII activity in the ME, and a partial reversion of the reduction in PVN pro-TRH mRNA levels and the number of TRH neurons detected by immunohistochemistry. In fed animals, adrenalectomy and corticosterone treatment did not change ME PPII activity 72 hours later. Methimazole-induced hypothyroidism produced a profound drop in tanycytes PPII mRNA levels, which was reverted by 3 days of treatment with T4. The activity of thyroliberinase, the serum isoform of PPII, was increased at most fasting time points studied. We conclude that delayed increases in both the ME PPII as well as the thyroliberinase activities in fasted male rats may facilitate the maintenance of the deep down-regulation of the HPT axis function, despite a partial reactivation of TRH expression in the PVN

Accessible routes integrating data from multiple sources

Providing citizens with the ability to move around in an accessible way is a requirement for all cities today. However, modeling city infrastructures so that accessible routes can be computed is a challenge because it involves collecting information from multiple, large-scale and heterogeneous data sources. In this paper, we propose and validate the architecture of an information system that creates an accessibility data model for cities by ingesting data from different types of sources and provides an application that can be used by people with different abilities to compute accessible routes. The article describes the processes that allow building a network of pedestrian infrastructures from the OpenStreetMap information (i.e., sidewalks and pedestrian crossings), improving the network with information extracted obtained from mobile-sensed LiDAR data (i.e., ramps, steps, and pedestrian crossings), detecting obstacles using volunteered information collected from the hardware sensors of the mobile devices of the citizens (i.e., ramps and steps), and detecting accessibility problems with software sensors in social networks (i.e., Twitter). The information system is validated through its application in a case study in the city of Vigo (Spain).This work was supported in part by the project Friendly barrierLess AdapTable City (FLATCity) (Ministerio de Ciencia, innovación y Universidades/ERDF, EU) funded by the Spanish Agencia Estatal de Investigación (AEI, doi 10.13039/501100011033), and in part by the European Regional Development Fund (ERDF), under Grants TIN2016-77158-C4-1-R, TIN2016-77158-C4-2-R and TIN2016-77158-C4-3-R. This work was also supported in part by the project Massive Geospatial Data Storage and Processing for Intelligent and Sustainable Urban Transportation (MaGIST), funded by the Spanish Agencia Estatal de Investigación (AEI, doi 10.13039/501100011033) under grants PID2019-105221RBC41, PID2019-105221RB-C43 and PID2019-105221RB-C44. The research of Miguel R. Luaces was also partially founded by: Xunta de Galicia/FEDER-UE GRC: ED431C 2017/58 and Xunta de Galicia/FEDER-UE, ConectaPeme, GEMA: IN852A 2018/14. Miguel R. Luaces also wishes to acknowledge the support received from the Centro de Investigación de Galicia "CITIC", funded by Xunta de Galicia and the European Union (European Regional Development Fund- Galicia 2014-2020 Program), by grant ED431G 2019/01. Jesús Balado and Lucía Díaz-Vilariño would like to thank to the Xunta de Galicia given through human resources grants ED481B-2019-061 and ED481D 2019/020, respectively

A pilot study on the Spanish version of the Psychosocial Adjustment to Illness Scale (PAIS‐SR) with carers of people with Parkinson's disease

Aim: To report the cross-cultural adaptation and pilot study of the ongoing validation of the Spanish version of the Psychosocial Adjustment to Illness Scale with carers of people with Parkinson's disease. Design: Cross-cultural adaptation and pilot study with a cross-sectional validation design of the Spanish version of the Psychosocial Adjustment to Illness Scale - Carers. Methods: Twenty-one carers of people with Parkinson's disease from a Primary Care practice in Spain were recruited and completed the PAIS-Carers, the SF-36 Health Survey, the Brief COPE Inventory and an assessment form. SPSS 23.0 was used to determine viability/acceptability and preliminary aspects of internal consistency of the instrument. Results: Five of the seven domains presented floor effect (71.42%), and only one presented ceiling effect (14.28%). The internal consistency of the scale and domains showed acceptable values (over 0.7). The content validity of the Spanish version seemed satisfactory with positive comments in general from participants

Static Analysis-based Debugging, Certification, Testing, and Optimization with CiaoPP

Facilitate the development of safe, efficient programs. Approach: •Next-generation, higher-level, multiparadigm prog. languages. •Improved program development environments. •A framework (CiaoPP) which integrates: •Debugging. •Verification and certification. •Testing. •Optimization (optimized compilation, parallelization, ...

Apoptotic cells subjected to cold/warming exposure disorganize apoptotic microtubule network and undergo secondary necrosis

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath the plasma membrane which plays a critical role in preserving cell morphology and plasma membrane integrity. The aim of this study was to examine the effect of cold/warming exposure on apoptotic microtubules and plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptotic H460 cells that cold/warming exposure disorganized apoptotic microtubules and allowed the access of active caspases to the cellular cortex and the cleavage of essential proteins in the preservation of plasma membrane permeability. Cleavage of cellular cortex and plasma membrane proteins, such as ¿-spectrin, paxilin, focal adhesion kinase and calcium ATPase pump (PMCA-4) involved in cell calcium extrusion resulted in increased plasma permeability and calcium overload leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the addition of the pan-caspase inhibitor z-VAD during cold/warming exposure that induces AMN depolymerization avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Likewise, apoptotic microtubules stabilization by taxol during cold/warming exposure also prevented cellular cortex and plasma membrane protein cleavage and secondary necrosis. Furthermore, microtubules stabilization or caspase inhibition during cold/warming exposure was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that cold/warming exposure of apoptotic cells induces secondary necrosis which can be prevented by both, microtubule stabilization or caspase inhibition.This work was supported by FIS PI10/00543 Grant, FIS EC08/00076 Grant, Ministerio de Sanidad, Spain and Fondo Europeo de Desarrollo Regional (FEDER-Unión Europea), SAS 111242 Grant, Servicio Andaluz de Salud-Junta de Andalucía, Proyecto de Investigación de Excelencia de la Junta de Andalucía CTS-5725, and by Asociación de Enfermos de Patología Mitocondrial (AEPMI).Peer Reviewe

Thermal Stability of Sol-Gel Derived 6 Mole%CaO-ZrO₂ Ceramics

The thermal behavior of the hyperfine interaction at Zr sites on two sol-gel derived 6 mole% CaO-ZrO₂ powders, obtained from the particulate and non-particulate regimes, has been studied by Perturbed Angular Correlations and complementary techniques. The aim was to get experimental support on the thermal stability of the obtained material in order to see the advantages of the different preparation regimes. The results could be interpreted in terms of the different microstructures and nanoscopic configurations exhibited by the resulting powders. After crystallization both powders showed the hyperfine nanoconfigurations of metastable tetragonal zirconia. In the sample obtained following the hydrolysis and the condensation processes via a particulate regime, the undesirable phase transformation towards the monoclinic form of zirconia is inhibited up to higher temperatures.Instituto de Física La Plat