1,559 research outputs found

    Navigation system using passive collaborative control adapted to user profile for a rollator device

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    In order to achieve this goal, research in different areas has been necessary. First, a methodology to provide human-like platform motion in reactive navigation algorithms has been proposed to improve user acceptance of help. Then, work has focused on gait analysis and user's condition estimation using only onboard sensors. In addition, a new methodology to evaluate fall risk using only onboard sensors while users walk has been proposed to balance the contribution of user and robot to control. All proposed subsystems have been validated with a set of volunteers at two rehabilitation hospitals: Fondazione Santa Lucia (Rome) and Hospital Regional Universitario (Malaga). Volunteers presented a wide variety of physical and cognitive disabilities. Tests with healthy volunteers have been discarded from the beginning to avoid a sampling bias error. Obtained results have shown that the proposed system can be used for: i) reactively generating human-like trajectories that outperforms all other tested algorithms in terms of likeness to human paths and success rate; ii) monitoring gait and user's condition while users walk using only on-board sensors; and iii) evaluating fall risk without wearable sensors nor ambient sensors. This thesis open a number of open research lines: i) user condition estimation can be extended to another medical scales; ii) the method to reactively generate human-like-trajectories can be extended to add deliberative human-adapted-path-planning; and iii) the fall risk estimator can be extended to a fall risk predictor.Rollators provide autonomy to persons with mobility impairments. These platforms can be used while people perform their Activities of Daily Living in order to provide support and/or balance. Also, they can be used during the rehabilitation process to strengthen the lower limbs or to provide balance before users can progress to canes or crutches. Rollators have a limited set of personalization options, but they are usually related to the users' body size. Hence, people who need extra typically have to choose a wheelchair instead. This transition to a wheelchair limits users' movements and it increases their disuse syndrome because they do not exercise their lower limbs. Hence, it is a priority to extent the use of rollator platforms as much as possible by adapting help to people who can not use a conventional rollator on their own. Technological enhancements can be added to rollator to expand their use to a larger population. For example, force sensors on handlebars provide information about users' weight bearing. This information can be used during rehabilitation to control their partial weight-bearing. Encoders on wheels may also provide useful information about the walking speed, which is a well know estimator of fall risk. In addition to monitorization, motors can be attached to the wheels for assistance, e.g. to reduce effort while ascending slopes. This thesis focuses on creating a navigation system for a robotized rollator, which includes weight bearing sensors, encoders and wheel motors. The navigation system relies on passive collaborative control to continuously combine user and system commands in a seamless way. The main contribution of this work is adaptation to the user's needs through continuous, transparent monitorization and profile estimation

    Improving the Quality of Teaching Internships with the Help of the Platforms

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    This article presents an empirical study on the perceptions of university students toward the development of the teaching practicum, using the CourseSites platform as a communication and support tool for their training. The opinions of the students were collected through a questionnaire. The sample consisted of 1500 students who were registered in the degrees of Early Childhood Education, Primary Education and Pedagogy (2008-2018). A descriptive, inferential and multi-level analysis was conducted, which confirmed that future teachers had activated their professional competences, as they had the chance to share their internship experiences with their faculty members and with their own classmates

    Hemimicelles of Alkyl Carboxylates Chemisorbed onto Magnetic Nanoparticles: Study and Application to the Extraction of Carcinogenic Polycyclic Aromatic Hydrocarbons in Environmental Water Samples

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    II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

    Apuntes de Planificación, gestión y desarrollo de proyectos

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    Apuntes de la asignatura Planificación, gestión y desarrollo de proyectos del Máster en Sistemas Electrónicos para Entornos Inteligente

    Characterisation of myocardial bridges in pigs: a comparative anatomical analysis with the human heart

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    Background: Few studies have been conducted in pigs concerning the presence of myocardial bridges (MB) on the coronary arteries and their branches, and some of them have evaluated small samples. The objective of this study was to characterise MB in pigs of commercial breeds. Materials and methods: One hundred and fifty eight hearts of pigs destined to the slaughterhouse with stunning method were studied. The coronary arteries were perfused with polyester resin (palatal 85% and styrene 15%) and then subjected to potassium hydroxide infusion to remove the subepicardial fat. Results: Ninety three MB were found in 67 (42.4%) specimens, 43 (46%) of which were located on branches of the right coronary artery, 38 (41%) on branches of the left coronary artery and 12 (13%) on both vessels. The MB occurred in 26 (38.8%) females and 41 (61.2%) males, but the difference was not statistically significant (p = 0.23). Single MB were most common (70%), followed by the presence of 2 (21%) MB in different vessels. the subsinusal interventricular artery was the vascular structure with the largest number of MB (46.2%), with its middle third being the most compromised segment (79%). The mean length of the MB was 11.23 ± 5.67 mm and the thickness of the suprapontine myocardium was 1.13 ± 0.48 mm. Conclusions: The frequency, localisation, and length of the MB reported in pigs are consistent with the findings of the present study, whereas in humans the MB involve mainly the anterior interventricular artery and are longer

    On the gravitational content of molecular clouds and their cores

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    (Abridged) The gravitational term for clouds and cores entering in the virial theorem is usually assumed to be equal to the gravitational energy, since the contribution to the gravitational force from the mass distribution outside the volume of integration is assumed to be negligible. Such approximation may not be valid in the presence of an important external net potential. In the present work we analyze the effect of an external gravitational field on the gravitational budget of a density structure. Our cases under analysis are (a) a giant molecular cloud (GMC) with different aspect ratios embedded within a galactic net potential, and (b) a molecular cloud core embedded within the gravitational potential of its parent molecular cloud. We find that for roundish GMCs, the tidal tearing due to the shear in the plane of the galaxy is compensated by the tidal compression in the z direction. The influence of the external effective potential on the total gravitational budget of these clouds is relatively small, although not necessarily negligible. However, for more filamentary GMCs, the external effective potential can be dominant and can even overwhelm self-gravity, regardless of whether its main effect on the cloud is to disrupt it or compress it. This may explain the presence of some GMCs with few or no signs of massive star formation, such as the Taurus or the Maddalena's clouds. In the case of dense cores embedded in their parent molecular cloud, we found that the gravitational content due to the external field may be more important than the gravitational energy of the cores themselves. This effect works in the same direction as the gravitational energy, i.e., favoring the collapse of cores. We speculate on the implications of these results for star formation models.Comment: Accepted for publication in MNRA

    New air castles (at1430): readings and rewrittings of the milkmaid`s tale and some new versions

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    [Resumen] El trabajo parte de la idea de que los textos populares mantienen un diálogo intercultural que permite reconocer muestras base con diferentes variantes, adaptadas según los momentos y el espacio. A partir del cuento de la lechera, que recrea el motivo de castillos en el aire (AT1430), se realiza un repaso histórico - comparativo a las versiones hispánicas de la fábula conocidas hasta la actualidad, relacionándolas con producciones de otras culturas y, finalmente, se da cuenta de algunas reescrituras de los últimos años, particularmente de la literatura in fantil y juvenil , que reinterpretan el motivo clásico[Abstract] A number of studies and reports have confirmed that popular texts maintain an in tercultural dialogue in which we can recognize basic samples with different variants adapted according to the time and space. From the tale of the milkmaid, which recreates the motif Air castles (AT1430), it performed an historical - comparative review to the spanish versions of the story to the present, relating them to productions of other cultures and finally it offers versions, not studied until now, of rewritings of the twentieth century, particularly in children's literature

    Gravitational Collapse and Filament Formation: Comparison with the Pipe Nebula

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    Recent models of molecular cloud formation and evolution suggest that such clouds are dynamic and generally exhibit gravitational collapse. We present a simple analytic model of global collapse onto a filament and compare this with our numerical simulations of the flow-driven formation of an isolated molecular cloud to illustrate the supersonic motions and infall ram pressures expected in models of gravity-driven cloud evolution. We apply our results to observations of the Pipe Nebula, an especially suitable object for our purposes as its low star formation activity implies insignifcant perturbations from stellar feedback. We show that our collapsing cloud model can explain the magnitude of the velocity dispersions seen in the 13^{13}CO filamentary structure by Onishi et al. and the ram pressures required by Lada et al. to confine the lower-mass cores in the Pipe nebula. We further conjecture that higher-resolution simulations will show small velocity dispersions in the densest core gas, as observed, but which are infall motions and not supporting turbulence. Our results point out the inevitability of ram pressures as boundary conditions for molecular cloud filaments, and the possibility that especially lower-mass cores still can be accreting mass at significant rates, as suggested by observations.Comment: 10 pages, 4 figures, accepted by Ap
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