Continuous Forest Fire Propagation in a Local Small World Network Model

This paper presents the development of a new continuous forest fire model implemented as a weighted local small-world network approach. This new approach was designed to simulate fire patterns in real, heterogeneous landscapes. The wildland fire spread is simulated on a square lattice in which each cell represents an area of the land's surface. The interaction between burning and non-burning cells, in the present work induced by flame radiation, may be extended well beyond nearest neighbors. It depends on local conditions of topography and vegetation types. An approach based on a solid flame model is used to predict the radiative heat flux from the flame generated by the burning of each site towards its neighbors. The weighting procedure takes into account the self-degradation of the tree and the ignition processes of a combustible cell through time. The model is tested on a field presenting a range of slopes and with data collected from a real wildfire scenario. The critical behavior of the spreading process is investigated

Self-assembly of triblock copolymers in aqueous solution

Indexación: ScieloThe aggregation of PE4VP-b-PS-b-PE4VP block copolymers was studied in aqueous solution. Triblock copolymers P4VP-b-PS-b-P4VP were synthesized by sequential anionic polymerization of poly(styrene) and poly(4-vinylpirydine) using sodium naphthalene as a bifunctional initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PE4VP-b-PS-b-PE4VP block copolymers. Both star and crew-cut micelles were formed. The concentrations at which micelles are formed cmc were determined, by steady-state and time-resolved fluorescence probing methods, as a function of quatemization degree. The results indicate that cmc of crew-cut micelles increases with increasing charge density of the PE4VP blocks. For star micelles there is not a clear dependency of cmc with the percentage of quatemization. The lifetime of pyrene fluorescence and the ratio I1/I3 were determined at concentrations of copolymers well above the cmc, and the results show that the location of pyrene into the micelle changes with the charge density of the micelle corona. The micropolarity sensed by pyrene decreases with increasing quatemization degree. The presence of aggregates was confirmed by transmission electronic microscopy.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072008000200013&lng=es&nrm=is

Sum-of-squares of polynomials approach to nonlinear stability of fluid flows: an example of application

With the goal of providing the first example of application of a recently proposed method, thus demonstrating its ability to give results in principle, global stability of a version of the rotating Couette flow is examined. The flow depends on the Reynolds number and a parameter characterising the magnitude of the Coriolis force. By converting the original Navier-Stokes equations to a finite-dimensional uncertain dynamical system using a partial Galerkin expansion, high-degree polynomial Lyapunov functionals were found by sum-of-squares-of-polynomials optimization. It is demonstrated that the proposed method allows obtaining the exact global stability limit for this flow in a range of values of the parameter characterising the Coriolis force. Outside this range a lower bound for the global stability limit was obtained, which is still better than the energy stability limit. In the course of the study several results meaningful in the context of the method used were also obtained. Overall, the results obtained demonstrate the applicability of the recently proposed approach to global stability of the fluid flows. To the best of our knowledge, it is the first case in which global stability of a fluid flow has been proved by a generic method for the value of a Reynolds number greater than that which could be achieved with the energy stability approach

Is UV laser ablation a suitable tool for geochemical analysis of organic rich source materials?

Abstract not available

A Novel Low-Cost Sensor Prototype for Nocturia Monitoring in Older People

Indexación: Scopus.This work was supported in part by CORFO - CENS 16CTTS-66390 through the National Center on Health Information Systems, in part by the National Commission for Scientific and Technological Research (CONICYT) through the program STIC-AMSUD 17STIC-03: ‘‘e-MONITOR âĂŞ Chronic Disease: Ambient Assisted Living and vital teleMONOTORing for e-health,’’ FONDEF ID16I10449 ‘‘Sistema inteligente para la gestión y análisis de la dotación de camas en la red asistencial del sector público,’’ and MEC80170097 ‘‘Red de colaboración científica entre universidades nacionales e internacionales para la estructuración del doctorado y magister en informática médica en la Universidad de Valparaíso.’’ The work of V. H. C. de Albuquerque was supported by the Brazilian National Council for Research and Development (CNPq) under Grant #304315/2017-6.Nocturia is frequently defined as the necessity to get out of bed at least one time during the night to urinate, with each of these episodes being preceded and continued by sleep. Several studies suggest that an increase of nocturia is seen with the onset of age, occurring in around 70% of adults over the age of 70. Its appearance is associated with detrimental quality of life for those who present nocturia, since it leads to daytime sleepiness, cognitive dysfunction, among others. Currently, a voiding diary is necessary for nocturia assessment; these are prone to bias due to their inherent subjectivity. In this paper, we present the design of a low-cost device that automatically detects micturition events. The device obtained 73% in sensibility and 81% in specificity; these results show that systems such as the proposed one can be a valuable tool for the medical team when evaluating nocturia. © 2013 IEEE.https://ieeexplore.ieee.org/document/845445

A transversal study on the way of acquisition of the interrogative in english in a group of students in the second cycle of compulsory secondary education (ESO). Educational implications

Este artículo comienza con una revisión general sobre algunos de los aspectos y hallazgos más importantes en el campo de la adquisición de segundas lenguas (SLA) desde una doble perspectiva psicolingüística y didáctica. Nos referiremos a las dicotomías cognición / automatización, inducción / deducción y adquisición / aprendizaje, junto al papel de las interrogativas en la lengua hablada a través de las principales corrientes de influencia. También estudiaremos la relación entre los conceptos de construcciones transicionales e interlengua y las etapas de desarrollo de las interrogativas en conversación. Seguidamente, comentaremos la relación existente entre las interrogativas y el texto narrativo. Más tarde procederemos al análisis y descripción de la producción verbal de interrogativas por parte de un grupo de estudiantes de inglés como lengua extranjera. Nuestro estudio está basado en un corpus de 69 preguntas producidas por 63 estudiantes en el segundo ciclo de Educación Secundaria. Nuestro análisis corrobora algunas de las hipótesis actuales sobre la adquisición de las interrogativas: a) el uso de fórmulas por parte de nuestros estudiantes, y b) la coherencia de su proceso de adquisición de la interrogativa con las etapas naturales en el desarrollo de dicha estructura. Para terminar, intentaremos establecer algunas implicaciones educativas para la enseñanza de las interrogativas en Educación Secundaria.This paper starts with a general revision on some of the most important aspects and findings in the field of Second Language Acquisition (SLA) from both a psycholinguistic and a didactic perspective. We will refer to the dichotomies cognition / automation, induction / deduction and acquisition / learning, together with the role of the interrogative in the spoken language throughout the main influential currents. We will also study the relationship between the concepts of transitional constructions and interlanguage and the stages of development of interrogatives in conversation. After that, we will comment on the relationship between the interrogatives and the narrative text. Later, we will go on with the analysis and description of the verbal production of interrogatives on the part of a group of students of English as a Foreign Language. Our study is based on a corpus of 69 questions produced by 63 students in the second cycle of Secondary Education. Our analysis corroborates some of the current hypotheses on the acquisition of interrogatives: a) the use of formulas on the part of our students, and b) the coherence of their process of acquisition of the interrogative with the natural stages in the development of this structure. To finish, we will try to set some educational implications for the teaching of interrogatives in Secondary Education.