8,797 research outputs found
Motivations of the University s tudents in the physical and sports practice of free time. The nautical activities
El estudio de los perfiles motivacionales proporciona información detallada sobre los
hábitos de
los grupos de personas hacia la práctica de la actividad física, permitiendo
poder
fomentar una motivación más positiva y conseguir una mayor adherencia a la práctica. Así el
objetivo de este estudio
ha sido clarificar cuáles son las motivaciones frente
a la práctica de actividad
físico
-deportiva de una muestra de jóvenes universitarios, incidiendo especialmente en las actividades
náuticas. La muestra estuvo compuesta por 1011 estudiantes de la Universidad de Almería (España).
El instrumento utilizado
fue
el cuestionario de hábitos físicos
-deportivos y de práctica de deportes
náuticos
. Los resultados obtenidos apuntan que los principales motivos para desarrollar la práctica
deportiva fueron la flexibilidad horaria y una adecuada a la disponibilidad de su tiempo libre, seguido
de la cercanía a su domicilio de las instalaciones. Otros motivos son por diversión, o estar con su grupo
de amigos. Respecto a las actividades náuticas, se decide practicar o no sólo porque les gustan, seguido
del interés por estar en contacto con el medio natural y acuático. Las modalidades náuticas más
practicadas son el piragüismo y la natación. En relación al abandono de la práctica deportiva,
claramente se produce por la falta de tiempo por el estudio o el trabajo. Es evidente
que la falta de
tiempo por los estudios o por el trabajo, perjudica gravemente la adherencia a la actividad física, pero
existen porcentajes muy altos de personas (62%) que admiten no practicar por pereza y desgana, por lo
que se deben buscar nuevas estra
tegias de motivación para que aumente la adherencia a la actividad
físico deportiva
Numerical simulations of thixotropic semi-solid aluminium alloys in open-rotor and rotor-stator mixers
This research uses the Bautista-Manero-Puig (BMP) model to examine flow patterns of semi-solid aluminium alloys (Al) in open-rotor and stator-rotor mixers via numerical solutions. The model captures the distinct thixo-viscoelastic behavior of the Al-alloys at low temperatures, near melting point. The analysis involves using 2D structured-meshes for open-rotor and rotor-stator geometries. Solutions for Newtonian and thixo-viscoelastic model fluids are reported through fields of velocity, strain-rate, stress, fluidity, and streamlines, revealing distinct features. Findings reveal nonlinear thixo-viscoelastic vortex patterns that vary with rotational speed, resulting in different fluidity and stress profiles compared to the invariant response of Newtonian fluids. At lower rotational speeds, rotor-pallets are dominated by structured material that gradually becomes unstructured to cover the outer vessel walls. When including a stator, the inner stator region resembles the Newtonian solution, but the outflow through stator gaps is reduced due to flow-structure levels outside. This information is of interest for industrial design and optimization of molten Al-alloy processing.Programa de Transferencia de Tecnología de la DFB
FEDER
Consejo Nacional de Ciencias, Humanidades y Tecnologı́as (CONAHCYT, Mexico)
Universidad Nacional Autónoma de México UNA
Instrumentation and automation system defects detection
EN: This paper presents the methodology used for the automation of a mechatronic system, which will be used for information of teeth, the work was done using a microcontroller, which allows the reconfiguration of the system, the use of different ports communication and input-output ports, It was made a distance measuring system which allows the microcontroller to provide information about current position of each axis of the mechanism. Control routines are performed which allow manipulation mechanism on each axis independently of thus obtained independent control shaft which facilitates its positioning in any point of the working space of the mechanism to obtain about the theet. UK: У статті подано методику, що використовується для автоматизації механотронної системи, з метою отримання інформації про стан зубів. Автоматизована система включає мікроконтролер, що дозволяє її реконфігурацію і порти комунікації та уведення-виведення. Було розроблено систему вимірювання відстаней, яка дозволяє мікроконтролеру надавати інформацію про поточний стан кожної осі механізму. Розроблено програми управління, що забезпечують вільне переміщення механізму по кожній осі. Таким чином, програми забезпечують незалежне управління, що, в свою чергу, сприяє позиціонуванню механізму в будь-якій точці робочого простору для отримання інформації про стан зубів
Standard and Non-Standard Physics in Neutrino Oscillations
We analyze the impact of recent solar and atmospheric data in the
determination of the neutrino oscillation parameters, taking into account that
both the solar nu_e and the atmospheric nu_mu may convert to a mixture of
active and sterile neutrinos. Furthermore, in the context of the atmospheric
neutrino problem we discuss an extended mechanism of neutrino propagation which
combines both oscillations and non-standard neutrino-matter interactions. We
use the most recent neutrino data, including the 1496-day Super-K solar and
atmospheric data samples, the latest SNO spectral and day/night solar data, and
the final MACRO atmospheric results. We confirm the clear preference of all the
data for pure-active oscillation solutions, bounding the fraction of sterile
neutrino involved in oscillations to be less than 52% in the solar sector and
less than 40% in the atmospheric sector, at 3 sigma. For the atmospheric case
we also derive a bound on the total amount of non-standard neutrino-matter
interactions, bounding the flavor-changing component to -0.03 <= epsilon <=
0.02 and the non-universal component to |epsilon'| <= 0.05.Comment: 6 pages, LaTeX file using espcrc2.sty, 1 table and 3 figures
included. Talk given at the XXX International Meeting on Fundamental Physics
(Jaca, Spain, 28/01-1/02/2002
CHR11, a chromatin-remodeling factor essential for nuclear proliferation during female gametogenesis in Arabidopsis thaliana
Chromatin-remodeling factors regulate the establishment of transcriptional programs during plant development. Although 42 genes encoding members of the SWI2/SNF2 family have been identified in Arabidopsis thaliana, < 10 have been assigned a precise function on the basis of a mutant phenotype, and none have been shown to play a specific role during the gametophytic phase of the plant life cycle. A. thaliana chromatin-remodeling protein 11 (CHR11) encodes an imitation of switch (ISWI)-like chromatin-remodeling protein abundantly expressed during female gametogenesis and embryogenesis in Arabidopsis. To determine the function of CHR11 in wild-type plants, we introduced a hairpin construct leading to the production of double-stranded RNA, which specifically degraded the endogenous CHR11 mRNA by RNA interference (RNAi). Transcription of the RNAi-inducing hairpin RNA was driven by either a constitutive cauliflower mosaic virus 35S promoter (CaMV35S) acting at most stages of the sporophytic phase or a newly identified specific promoter acting at the onset of the female gametophytic phase (pFM1). All adult trans-formants that constitutively lacked sporophytic CHR11 activity showed reduced plant height and small cotyledonary embryos with limited cell expansion. In contrast, RNAi lines in which CHR11 was specifically silenced at the onset of female gametogenesis (megagametogenesis) had normal height and embryo size but had defective female gametophytes arrested before the completion of the mitotic haploid nuclear divisions. These results show that CHR11 is essential for haploid nuclear proliferation during megagametogenesis and cell expansion during the sporophytic phase, demonstrating the functional versatility of SW12/SNF2 chromatin-remodeling factors during both generations of the plant life cycle
Two experiments for the price of one? -- The role of the second oscillation maximum in long baseline neutrino experiments
We investigate the quantitative impact that data from the second oscillation
maximum has on the performance of wide band beam neutrino oscillation
experiments. We present results for the physics sensitivities to standard three
flavor oscillation, as well as results for the sensitivity to non-standard
interactions. The quantitative study is performed using an experimental setup
similar to the Fermilab to DUSEL Long Baseline Neutrino Experiment (LBNE). We
find that, with the single exception of sensitivity to the mass hierarchy, the
second maximum plays only a marginal role due to the experimental difficulties
to obtain a statistically significant and sufficiently background-free event
sample at low energies. This conclusion is valid for both water Cherenkov and
liquid argon detectors. Moreover, we confirm that non-standard neutrino
interactions are very hard to distinguish experimentally from standard
three-flavor effects and can lead to a considerable loss of sensitivity to
\theta_{13}, the mass hierarchy and CP violation.Comment: RevTex 4.1, 23 pages, 10 figures; v2: Typos corrected, very minor
clarifications; matches published version; v3: Fixed a typo in the first
equation in sec. III
SPH simulations of thixo-viscoplastic fluid flow past a cylinder
Thixotropic materials are complex fluids that display time-dependent viscosity and/or yield-stress response upon the application of a fixed deformation, while recovering their original structured-state when the deformation is discontinued. Thixotropic effects are presents in many different systems and applications, ranging from food products, such as ketchup, to metals, such as molten aluminum. In this work we present a first attempt to simulate the rheological properties of thixo-viscoplastic flows using a Smoothed Particle Hydrodynamic (SPH) method. The study set up is a 2D flow around a circular cylinder as well as a simple shear flow between parallel plates to validate our numerical results. SPH solutions are compared with simulations performed using the open-source Finite Volume Method solver RheoTool, based on OpenFOAM. The viscoplastic model used in this work is the Papanastasiou model combined with a recently developed microstructural one, in order to include thixotropy. In this thixo-viscoplastic framework, we analyze the flow properties in terms of yield-fronts, streamlines and structure-parameter fields at different Bingham and Thixotropy numbers, through microstructural thixotropic and yield-stress parameters variation. Obtained results show an important novelty: an asymmetry in the thixo-viscoplastic flow around the cylinder
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