Rogue waves of the Sasa-Satsuma equation in a chaotic wave field

We study the properties of the chaotic wave fields generated in the frame of the Sasa-Satsuma equation (SSE). Modulation instability results in a chaotic pattern of small-scale filaments with a free parameter - the propagation constant k. The average velocity of the filaments is approximately given by the group velocity calculated from the dispersion relation for the plane-wave solution. Remarkably, our results reveal the reason for the skewed profile of the exact SSE rogue-wave solutions, which was one of their distinctive unexplained features. We have also calculated the probability density functions for various values of the propagation constant k, showing that probability of appearance of rogue waves depends on k

Fatigue crack characterisation in 2024-T351 aluminium alloy through SEM observation combined with the CJP model

This work characterises crack growth in AA2024-T315 by combining different methods to further increase the reliability of the results. The Christopher-James-Patterson (CJP) model was fitted to experimental data obtained by digital image correlation (DIC). The effective value of the CJP stress intensity factors were successfully correlated with the ΔK-da/dN curve as obtained with Scanning Electron Microscopy measurements of the depth of striations on the fracture surface. This approach based on fitting the CJP model with DIC data and SEM observations allowed estimation of opening and closure loads and allowed the propagation rate and fracture mode to be effectively characterised.The authors would like to acknowledge the financial support of Programa Operativo FEDER from the Junta de Andalucia (Spain) through grant reference UMA18-FEDERJA-250. Industrial support from Bettergy SL and from Dr N Ordonez and M Carrera is also greatly acknowledged, as well as access to different components and materials in the energy industry. The authors would also like to acknowledge the financial support from Junta de Andalucia through the research project “1380786” funded by the program “Proyectos de I + D + I en el Marco del Programa Operativo FEDER Andalucia 2014-2020. Convocatoria 2020.” We would also like to acknowledge funding for open access charge: Universidad de Malaga / CBU

How online search behavior is influenced by user-generated content on review websites and hotel interactive websites

ABSTRACT: Purpose – The purpose of this paper is to advance in research on consumer Psychology of hospitality, since it investigates how online search behavior of users (particularly, information search and choice) is influenced by the opinions of other people in a new context characterized by the generalized use of Web 2.0 applications. Design/methodology/approach – Empirical research was carried out in the hotel sector in Iberian Peninsula, where two Web 2.0 applications are especially relevant for users: the review Web sites and the hotel interactive Web sites. A qualitative method (in-depth interviews with hotel managers) and a quantitative technique (personal surveys to a sample of 830 users) were used to conduct this research. Findings – The results indicates that the perceived influence on behavior of the user-generated content on these Web 2.0 applications is determined, in both cases, by the value of the information, the credibility of the sources and the degree of similarity between the user and the creators of content. Practical implications – Firms should have an active presence in the review Web sites and the hotel interactive Web sites, and use these platforms for market research and communication. Firms should engage users to post content, support their credibility and facilitate the evaluation of the content generators’ similarity. Originality/value – This paper is the first study in the hospitality literature that develops and empirically tests an integrative model explaining the perceived influence on behavior of user-generated content on Web 2.0 applications

Evaporation Forecasting through Interpretable Data Analysis Techniques

©2022. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the Published, version of a Published Work that appeared in final form in Electronics. To access the final edited and published work see https://doi.org/10.3390/electronics11040536Climate change is increasing temperatures and causing periods of water scarcity in arid and semi-arid climates. The agricultural sector is one of the most affected by these changes, having to optimise scarce water resources. An important phenomenon within the water cycle is the evaporation from water reservoirs, which implies a considerable amount of water lost during warmer periods of the year. Indeed, evaporation rate forecasting can help farmers grow crops more sustainably by managing water resources more efficiently in the context of precision agriculture. In this work, we expose an interpretable machine learning approach, based on a multivariate decision tree, to forecast the evaporation rate on a daily basis using data from an Internet of Things (IoT) infrastructure, which is deployed on a real irrigated plot located in Murcia (southeastern Spain). The climate data collected feed the models that provide a forecast of evaporation and a summary of the parameters involved in this process. Finally, the results of the interpretable presented model are validated with the best literature models for evaporation rate prediction, i.e., Artificial Neural Networks, obtaining results very similar to those obtained for them, reaching up to 0.85R2 and 0.6MAE. Therefore, in this work, a double objective is faced: to maintain the performance obtained by the models most frequently used in the problem while maintaining the interpretability of the knowledge captured in it, which allows better understanding the problem and carrying out appropriate actions

Smoothed particle hydrodynamics on GPU computing

Smoothed Particle Hydrodynamics (SPH) is a powerful technique used to simulate complex free-surface flows. However one of the main drawbacks of this method is the expensive computational runtime and the large number of particles needed when 3D simulations are performed. High Performance Computing (HPC) therefore becomes essential to accelerate these codes and perform simulations. In this study, parallelization using Graphics Processing Units (GPU) is applied to the SPHysics code (www.sphysics.org) dedicated to free-surface flows with SPH. Simulations involving several million particles on a single GPU exhibit speedups of up to two orders of magnitude over the same calculations using CPU codes, while parallelization using MPI for multi-GPU leads to further acceleration. This cheap technology allows studying real-life engineering problems at reasonable computational runtimes

Diel patterns of microphytobenthic primary production in intertidal sediments: the role of photoperiod on the vertical migration circadian rhythm

Diel primary production patterns of intertidal microphytobenthos (MPB) have been attributed to short-term physiological changes in the photosynthetic apparatus or to diel changes in the photoautotrophic biomass in the sediment photic layer due to vertical migration. Diel changes in primary production and vertical migration are entrained by external factors like photoperiod and tides. However, the role of photoperiod and tides has not been experimentally separated to date. Here, we performed laboratory experiments with sediment cores kept in immersion, in the absence of tides, with photoperiod or under continuous light. Measurements of net production, made with O-2 microsensors, and of spectral reflectance at the sediment surface showed that, in intertidal sediments, the photoperiod signal was the major driver of the diel patterns of net primary production and sediment oxygen availability through the vertical migration of the MPB photoautotrophic biomass. Vertical migration was controlled by an endogenous circadian rhythm entrained by photoperiod in the absence of tides. The pattern progressively disappeared after 3 days in continuous light but was immediately reset by photoperiod. Even though a potential contribution of a subjective in situ tidal signal cannot be completely discarded, Fourier and cross spectral analysis of temporal patterns indicated that the photosynthetic circadian rhythm was mainly characterized by light/dark migratory cycles

Parasitismo em ruminantes do concelho de Coruche (Portugal)

Apresentação em painel.Entre Março e Agosto de 2007 efectuou-se um estudo parasitológico em efectivos bovinos de raças de carne e Brava e ovinos de raça Merino Branco do Concelho de Coruche, explorados em regime extensivo e sujeitos a um programa profiláctico para helmintes e ectoparasitas, visando a determinação das principais helmintoses presentes. Nas oito freguesias do concelho e de acordo com o número de explorações/número de animais, colheu-se um total de 206 amostras de fezes em bovinos de carne, 30 em bovinos de raça Brava e 71 em ovinos. As amostras foram sujeitas a análises coprológicas, com base em métodos qualitativos e quantitativos (técnicas de Willis, de sedimentação e de McMaster). Em seis das explorações onde se detectou Fasciola hepatica, procedeu-se à prospecção dos biótopos do molusco hospedeiro intermediário (HI). A eliminação de ovos, oocistos e/ou larvas de primeiro estadio (L1), foi registada em 53,40 % das amostras de fezes de bovinos de carne, em 63,33 % das de bovinos de raça Brava e de 87,31 % das de ovinos, com distribuição muito variável consoante as freguesias em estudo