Search results for "TRACK"

2020

Background Physical activity trackers (PATs) such as apps and wearable devices (eg, sports watches, heart rate monitors) are increasingly being used by young adolescents. Despite the potential of PATs to help monitor and improve moderate-to-vigorous physical activity (MVPA) behaviors, there is a lack of research that confirms an association between PAT ownership or use and physical activity behaviors at the population level. Objective The purpose of this study was to examine the ownership and use of PATs in youth and their associations with physical activity behaviors, including daily MVPA, sports club membership, and active travel, in 2 nationally representative samples of young adolescen…

Tracks induced in TeO2 by heavy ions at low velocities

2000

On the basis of its thermal properties, TeO2 crystal was selected as an insulator with low threshold electronic stopping power for track formation Set. The crystals were irradiated by S, Zn, Mo, Kr, Te and Pb ions and the optical absorption and track formation were studied. Comparison is made with the published results on LiNbO3 ,Y 3Fe5O12 and SiO2 quartz. Good quantitative agreement is found with the predictions of the thermal spike model of Szenes with respect to Set and the variation of the track size with the electronic stopping power Se. It is shown that TeO2 has a high eAciency g at low ion velocities, which is a characteristic feature of the damage cross-section velocity eAect. ” 200…

Hardening and formation of dislocation structures in LiF crystals irradiated with MeV–GeV ions

2002

Abstract Material modifications of LiF crystals irradiated with Au, Pb and Bi ions of MeV to GeV energy are studied by means of microindentation measurements and dislocation etching. Above a critical irradiation fluence of 10 9 ions/cm 2 , the microhardness can improve by a factor of 2 in the bulk and by more than 3 on the surface. Radiation-induced hardening follows the evolution of the energy loss along the ion path. Annealing experiments indicate that complex defect aggregates created in the tracks play a major role for the hardness change. Evidence for severe structural modifications is found when etching indentation impressions in highly irradiated crystals leading to similar pattern a…

Scanning and deep processing of information in hypertext: an eye tracking and cued retrospective think-aloud study

2016

When students solve problems on the Internet, they have to find a balance between quickly scanning large sections of information in web pages and deeply processing those that are relevant for the task. We studied how high school students articulate scanning and deeper processing of information while answering questions using a Wikipedia document, and how their reading comprehension skills and the question type interact with these processes. By analyzing retrospective think-aloud protocols and eye-tracking measures, we found that scanning of information led to poor hypertext comprehension, while deep processing of information produced better performance, especially in location questions. Thi…

Cueing complex animations: Does direction of attention foster learning processes?

2011

Abstract The time course of learners’ processing of a complex animation was studied using a dynamic diagram of a piano mechanism. Over successive repetitions of the material, two forms of cueing (standard colour cueing and anti-cueing) were administered either before or during the animated segment of the presentation. An uncued group and two other control conditions were also employed. Development of an internal representation of the movements depicted in the animation was evaluated through participant demonstrations of the mechanism’s operation on a replica piano mechanism. Eye tracking (fixation lengths) indicated that overall, conventional visuospatially-based cueing was largely ineffect…

Visual Attention in Virtual Reality Settings: An Abstract

2019

Virtual reality, VR, is challenging marketers to understand both brand interaction and the customer experience at the point of sale. In order to test the usefulness of VR in retailing, research must address how the customer’s visual attention in a VR setting affects his/her behavior. There are two main drivers for this research. First, there has been an enormous growth in recent years in the use of neurophysiological methods to measure visual attention. At the store level, previous works show that attention to products measured through eye tracking influences consumer decision. Second, VR is being increasingly adopted by brands, but research is lacking into comparisons between VR formats. W…

Implementación de un display 3D basado en imagen integral

2018

Desde hace varios años, el desarrollo y la evolución de tecnologías capaces de registrar y/o reconstruir información 3D está en auge, principalmente debido al gran interés que despierta este campo de estudio. Entre estas tecnologías, destaca la técnica de Imagen Integral, debido principalmente a su capacidad de generar un imagen 3D que proporciona al sistema visual una respuesta similar a la que obtendría percibiendo un objeto 3D real. Aunque esta técnica no está exenta de limitaciones, se están realizando prometedores avances para resolver sus principales inconvenientes. En esta Tesis se estudia la técnica de imagen integral con el objetivo de implementar un monitor 3D que sir…

Interaction between turbulent structures and particles in roughened channel

2016

Abstract The distribution of inertial particles in turbulent flows is highly non-uniform and is driven by the local dynamics of the turbulent structures of the underlying carrier flow field. In the specific context of dilute particle-laden wall-bounded flows, deposition and resuspension mechanisms are dominated by the interaction between inertial particles and coherent turbulent structures characteristic of the wall region. The macroscopic behavior of these two-phase systems is influenced by particle inertia, which plays a role at the microscale of a single dispersed element. These turbulent structures, which control the turbulent regeneration cycles, are strongly affected by the wall rough…

Nanorod orientation control by swift heavy ion irradiation

2022

Highly energetic ions have been previously used to modify the shape of metal nanoparticles embedded in an insulating matrix. In this work, we demonstrate that under suitable conditions, energetic ions can be used not only for shape modification but also for manipulation of nanorod orientation. This observation is made by imaging the same nanorod before and after swift heavy ion irradiation using a transmission electron microscope. Atomistic simulations reveal a complex mechanism of nanorod re-orientation by an incremental change in its shape from a rod to a spheroid and further back into a rod aligned with the beam. Highly energetic ions have been previously used to modify the shape of meta…

FRIPON: a worldwide network to track incoming meteoroids

2020

Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile - hence precious - meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receiver…