510 research outputs found

    Relationship between intermittency and stratification

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    A formal analogy exists between 2D turbulence and 3D turbulence with stratification and rotation. Although the effect of the rotation, to the scale typical of the turbulence, is negligible in the atmosphere, we have found a relationship between the behavior of the intermittency and that of the atmospheric stratification. In order to do that, the intermittency has been characterized through the flatness of the PDFs of velocity increments, for the smallest possible scale, present in our measurements

    Am I Ibiza? Measuring brand identification in the tourism context

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    Understanding brand identification is critical when developing successful relationships between tourists and the destinations they visit. Nevertheless, there is an absence of academic work that measures tourist destination brand identification. The purpose of this study is to develop a scale to measure brand identification within the context of tourism. The study develops 24 measurement items to construct a survey instrument. The instrument is then administered to collect data from a sample of 308 Ibizan tourists. Following a rigorous scale development process, a one-dimensional brand identification model is identified. Finally, a refined scale consisting of seven measurement items is developed. This scale is validated with a new sample of 126 Ibizan visitors. Multi-step psychometric tests verify that the new brand identification scale is reliable and valid. Destination managers could use this scale to evaluate and identify highly acknowledged tourist segments, and more accurately implement the corresponding promotional strategies to this target.This research was funded by a grant from the Spanish Ministry of Science and Innovation (National Plan for Research, Development and Innovation ECO2014-59356-P and ECO2015-69103-R

    Preliminary study of Augmented Reality based manufacturing for further integration of Quality Control 4.0 supported by metrology

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    Augmented Reality (AR) is a key technology enabling Industry 4.0, which enriches human perspectives by overlaying digital information onto the real world. The maturity of AR technology has grown recently. As processes in the automotive and aeronautic sectors require high quality and near-zero error rates to ensure the safety of end-users, AR can be implemented to facilitate workers with immersive interfaces to enhance productivity, accuracy and autonomy in the quality sector. In order to analyse whether there is a real and growing interest in the use of AR as assisting technology for manufacturing sector in general and quality control in particular, two specific research questions are defined. In addition, two well-known research databases (Scopus, Web of Science) are used for the paper selection phase in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to conduct a preliminary study and evaluate the current development of AR applications in manufacturing sector in order to answer the defined questions. It is found that while the development of AR technology has widely implemented to assign real-time information to several systems and processes in assembly and maintenance sectors, this tendency has only emerged in the quality sector over the last few years. However, AR-based quality control has proved its advantages in improving productivity, accuracy and precision of operators as well as benefits to manufacturing in terms of product and process quality control across different manufacturing phases

    The anatomy of urban social networks and its implications in the searchability problem

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    The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure

    From lean production to lean 4.0: a systematic literature review with a historical perspective

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    Over recent decades, the increasing competitiveness of markets has propagated the term “lean” to describe the management concept for improving productivity, quality, and lead time in industrial as well as services operations. Its overuse and linkage to different specifiers (surnames) have created confusion and misunderstanding as the term approximates pragmatic ambiguity. Through a systematic literature review, this study takes a historical perspective to analyze 4962 papers and 20 seminal books in order to clarify the origin, evolution, and diversification of the lean concept. Our main contribution lies in identifying 17 specifiers for the term “lean” and proposing four mechanisms to explain this diversification. Our research results are useful to both academics and practitioners to return to the Lean origins in order to create new research areas and conduct organizational transformations based on solid concepts. We conclude that the use of “lean” as a systemic thinking is likely to be further extended to new research fields

    Implementation of a resistance training on young football players

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    El objetivo de este estudio, es comprobar el efecto de un programa de 20 sesiones de entrenamiento específico de fuerza en futbolistas jóvenes Participaron 38 sujetos en el estudio, divididos en un grupo experimental (GE) y un grupo control (GC). Al GE se le administró un entrenamiento de fútbol y un trabajo específico de fuerza; mientras el GC sólo efectuó práctica de fútbol. Ambos fueron evaluados al inicio y al final del programa, con el objetivo de conocer su fuerza dinámica máxima en los flexores y extensores de la rodilla; su masa muscular en las extremidades inferiores; el porcentaje de grasa; y, por último, la velocidad en las pruebas de 10 y 20 metros. Únicamente el GE mejora de forma muy significativa la fuerza dinámica máxima (p<0,01). No se encuentran diferencias en la masa muscular, ni en la velocidad. El GE y el GC incrementan el porcentaje de grasa corporalThe aim of this study is to check the effect of a specific training strength program on young footballers. 38 players took place in the study; they were divided into an experimental group (EG) and a control group (CG). The EG added a specific strength work to their football workout, whereas the CG just practised football. Both of them were assessed at the beginning and at the end of the program to know their maximum dynamic strength in their flexor and extensor muscles of their knees; their muscle mass in their lower extremities; their body mass and fat percentage; and their speed in the 10 and 20 metres trials. Just the EG improves remarkably their maximum dynamic strength … No differences in their muscle mass or in their movement strength are found. The EG and the CG increase their MBRate and their body fa

    Primitive neuroectodermal tumor of the uterus

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    Training focused on deep cervical muscles to prevent neck pain

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    El objetivo del estudio fue crear un programa de entrenamiento de la musculatura cervical profunda, para orientar a los profesionales de la actividad física y del deporte en el trabajo con ella. Hay muy pocas pautas relacionadas con el trabajo de ésta, al mismo tiempo que la literatura científica nos muestra su estrecha relación con el dolor cervical. Por ello, se utilizan las investigaciones previas para crear un programa de entrenamiento centrado en la musculatura cervical profunda. Así como sus correspondientes métodos de evaluación, entre los que se incluye un nuevo test de extensión cervical con el que se pretende conseguir una valoración de la fuerza y la resistencia más adecuada. Finalmente se presenta un estudio de caso de una mujer sin dolor cervical, pero con factores de riesgo asociados, que sigue el programa como forma de prevención, mostrando un claro progreso tras la finalización de esteThe objective of the study was to create a training program for deep cervical muscles and help physical activity and sports professionals when exercising them. There are very few guidelines related to exercising these muscles, but at the same time, scientific literature demonstrates its close connection with neck pain. Therefore, previous research is used in order to develop a training program focused on deep cervical muscles, as well as its corresponding evaluation methods, including a new cervical extensor test aimed at achieving a more accurate estimation of strength and resistance. Finally, a case study is presented; a woman not suffering from neck pain but having associated risk factors, who follows the program as a means of preventing it, showing clear progress after its completio

    Machine tool Verification According to Machine Configuration

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    AbstractMachine Tool verification is an important issue for metrology. In recent years several efforts has being done in order to increase the methods reliabilities. However, geometrical verification on shop floor and big machines has not being explore as widely, leaving work possibilities open. This article presents a ball bar-based formulae determination method for the 21 MT geometrical errors taking into account the specific machine configuration, as well as its verification and validation

    Injuries in Physical Education of High School. A Problem?

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    El control de la incidencia de lesiones en la clase de Educación Física debe ser un factor prioritario para la salud pública. El objetivo de este estudio es analizar la incidencia de lesiones en las clases de Educación Física (EF) y cómo se relacionan con la falta de participación de los estudiantes. Estudio de cohortes prospectivo. Conglomerado de muestreo bi-etapa para un total de 637 estudiantes. Las ausencias y las lesiones se registraron durante el curso escolar. De 1.463 sesiones, solo el 4,58% registró ausencias causadas por lesión (0,33% de la participación total esperada). La tasa de lesiones producidas en las clases de Educación Física fue de 1,90 por cada 1.000 horas de participación. La frecuencia de ausencia en las clases de Educación Física debido a una lesión es muy baja en comparación con la participación general esperada; por lo tanto, no es un factor que influya significativamente en la tasa de participación de los estudiantesThe incidence of injuries in physical education class should be a priority factor for public health. The aim of this study is to analyze the incidence of injuries in Physical Education (PE) lessons and how they relate to lack of full student participation. Prospective cohort study. Conglomerate bi-stage sampling for a total of 637 students. Absence and injuries were recorded for the school year. Of 1463 lessons, only 4.58% were documented with identification of the causal incident (0.33% of the total participation expected). The rate of injuries produced in PE lessons was of 1.90 for every 1000 hours of participation. The frequency of absence of in PE lessons due to injury is very low compared to the overall expected participation; therefore it is not a factor that influences the rate of student participation significantl
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