Parcourir Sciences Et Techniques par type de document "Article scientifique"
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Adiabatic invariants drive rhythmic human motion in variable gravity
01 décembre 2020, CeREF TechniqueArticle scientifiqueVoluntary human movements are stereotyped. When modeled in the framework of classical mechanics they are expected to minimize cost functions that may include energy, a natural candidate from a physiological point of view also. In time-changing environments, however, energy is no longer conserved—regardless of frictional energy dissipation—and it is therefore not the preferred candidate for any cost ... -
Anyons in quantum mechanics with a minimal length
15 février 2017, HE Louvain en HainautArticle scientifiqueThe existence of anyons, i.e. quantum states with an arbitrary spin, is a generic feature of standard quantum mechanics in (2+1)-dimensional Minkowski spacetime. Here it is shown that relativistic anyons may exist also in quantum theories where a minimal length is present. The interplay between minimal length and arbitrary spin effects are discussed. -
Cinématique du grand battement et du développé chez des danseurs amateurs : effets à court terme d’un étirement statique ou dynamique
11 décembre 2020, HE Louvain en HainautArticle scientifiqueLes jeunes danseurs amateurs semblent utiliser majoritairement l’étirement statique. Or, la littérature montre également l’efficacité de l’étirement dynamique sur la performance des sportifs. L’un de ces étirements est-il dès lors plus favorable à l’exécution de deux mouvements de danse classique, le grand battement et développé ? Seize participants ont réalisé ces mouvements dans trois conditions ... -
Clinical and MRI changes of puborectalis and iliococcygeus after a short period of intensive pelvic floor muscles training with or without instrumentation
13 juin 2018, HE Louvain en HainautArticle scientifiquePurpose This study evaluates the impact of a 3-week period of intensive pelvic floor muscles training (PFMT), with or without instrumentation, on clinical and static magnetic resonance imaging (MRI) changes of puborectalis (PR) and iliococcygeus (IL) muscles. Methods 24 healthy young women were enrolled in the study and 17 achieved the 9 sessions of 30 min training exercises and conducted all ... -
Compte rendu de P. Galluzzi, «Galileo, Rosmini, Darwin : triumviri del cattolicesimo riformatore (1870-1918)»
Article scientifiqueCompte rendu de P. Galluzzi, «Galileo, Rosmini, Darwin : triumviri del cattolicesimo riformatore (1870-1918)», in Rivista di filosofia, vol. 113, 2022, n°3, pp. 489-495. -
Diffusion in Phase Space as a Tool to Assess Variability of Vertical Centre-of-Mass Motion during Long-Range Walking
06 février 2023, CeREF SantéCeREF TechniqueArticle scientifiqueWhen a Hamiltonian system undergoes a stochastic, time-dependent anharmonic perturbation, the values of its adiabatic invariants as a function of time follow a distribution whose shape obeys a Fokker–Planck equation. The effective dynamics of the body’s centre-of-mass during human walking is expected to represent such a stochastically perturbed dynamical system. By studying, in phase space, the ... -
DYSKIMOT: An Ultra-Low-Cost Inertial Sensor to Assess Head’s Rotational Kinematics in Adults during the Didren-Laser Test
04 février 2020, CERISICArticle scientifiqueVarious noninvasive measurement devices can be used to assess cervical motion. The size, complexity, and cost of gold-standard systems make them not suited to clinical practice, and actually difficult to use outside a dedicated laboratory. Nowadays, ultra-low-cost inertial measurement units are available, but without any packaging or a user-friendly interface. The so-called DYSKIMOT is a home-designed, ... -
Ergonomic Risk Assessment of Developing Musculoskeletal Disorders in Workers with the Microsoft Kinect: TRACK TMS
19 octobre 2018, CeREF TechniqueArticle scientifiqueCompte rendu de la conférence JETSAN 2017 -
Fine adaptive precision grip control without maximum pinch strength changes after upper limb neurodynamic mobilization
30 juin 2021, HE Louvain en HainautArticle scientifiqueBefore and immediately after passive upper limb neurodynamic mobilizations targeting the median nerve, grip ( GF ) and load ( LF ) forces applied by the thumb, index and major fingers (three-jaw chuck pinch) were collected using a manipulandum during three different grip precision tasks: grip-lifthold- replace (GLHR), vertical oscillations (OSC), and vertical oscillations with up and down ... -
A First-Quantized Model for Unparticles and Gauge Theories around Conformal Window
02 décembre 2021, CeREF TechniqueArticle scientifiqueWe first quantize an action proposed by Casalbuoni and Gomis in 2014 that describes two massless relativistic scalar particles interacting via a conformally invariant potential. The spectrum is a continuum of massive states that may be interpreted as unparticles. We then obtain in a similar way the mass operator for a deformed action in which two terms are introduced that break the conformal symmetry: ... -
The Formulations of Classical Mechanics with Foucault’s Pendulum
01 octobre 2020, CERDECAMArticle scientifiqueSince the pioneering works of Newton (1643–1727), Mechanics has been constantly reinventing itself: reformulated in particular by Lagrange (1736–1813) then Hamilton (1805–1865), it now offers powerful conceptual and mathematical tools for the exploration of dynamical systems, essentially via the action-angle variables formulation and more generally through the theory of canonical transformations. ... -
Gravitating Bubbles of Gluon Plasma above Deconfinement Temperature
13 octobre 2020, CeREF TechniqueArticle scientifiqueThe equation of state of SU(3) Yang–Mills theory can be modelled by an effective Z3− symmetric potential depending on the temperature and on a complex scalar field ϕ . Allowing ϕ to be dynamical opens the way to the study of spatially localized classical configurations of the scalar field. We first show that spherically symmetric static Q-balls exist in the range (1−1.21)×Tc , Tc being the ... -
Head Pitch Angular Velocity Discriminates (Sub-)Acute Neck Pain Patients and Controls Assessed with the DidRen Laser Test
06 avril 2022, CeREF TechniqueArticle scientifiqueUnderstanding neck pain is an important societal issue. Kinematic data from sensors may help to gain insight into the pathophysiological mechanisms associated with neck pain through a quantitative sensorimotor assessment of one patient. The objective of this study was to evaluate the potential usefulness of artificial intelligence with several machine learning (ML) algorithms in assessing neck ... -
High Specificity of Single Inertial Sensor-Supplemented Timed Up and Go Test for Assessing Fall Risk in Elderly Nursing Home Residents
17 février 2022, CeREF TechniqueArticle scientifiqueThe Timed Up and Go test (TUG) is commonly used to estimate the fall risk in the elderly. Several ways to improve the predictive accuracy of TUG (cameras, multiple sensors, other clinical tests) have already been proposed. Here, we added a single wearable inertial measurement unit (IMU) to capture the residents’ body center-of-mass kinematics in view of improving TUG’s predictive accuracy. The aim ... -
Higher-derivative harmonic oscillators: stability of classical dynamics and adiabatic invariants
06 janvier 2019, CERISICArticle scientifiquehe status of classical stability in higher-deriv- ative systems is still subject to discussions. In this note, we argue that, contrary to general belief, many higher-derivative systems are classically stable. The main tool to see this prop- erty are Nekhoroshev’s estimates relying on the action-angle formulation of classical mechanics. The latter formulation can be reached provided the Hamiltonian ... -
Low-Cost Sensors and Biological Signals
21 février 2021, CeREF TechniqueArticle scientifiqueEditorial of the Special issue Low-Cost sensors and Biological signals https://www.mdpi.com/journal/sensors/special_issues/LCSBS -
Machine Learning Identifies Chronic Low Back Pain Patients from an Instrumented Trunk Bending and Return Test
03 juillet 2022, CeREF TechniqueArticle scientifiqueNowadays, the better assessment of low back pain (LBP) is an important challenge, as it is the leading musculoskeletal condition worldwide in terms of years of disability. The objective of this study was to evaluate the relevance of various machine learning (ML) algorithms and Sample Entropy (SampEn), which assesses the complexity of motion variability in identifying the condition of low back pain. ... -
Many-Quark Interactions: Large-N Scaling and Contribution to Baryon Masses
31 mai 2022, CeREF TechniqueArticle scientifiqueStarting from an effective Hamiltonian modeling, of a baryon made of N identical quarks in the large-N approach of QCD, we obtain analytical formulas, allowing to estimate the contributions of multiquark interactions to the baryon mass. The cases of vanishing (mass spectrum) and nonvanishing (baryon melting) temperatures are treated. -
Meson spectrum in SU(N) gauge theories with quarks in higher representations: A check of Casimir scaling hypothesis
01 juin 2020, CeREF TechniqueArticle scientifiqueGauge theories with gauge group and quarks belonging to arbitrary representations of SU(N) form a rich landscape of QCD-like theories, whose study can shed new light on the properties of confinement. Four cases are particularly worth of interest: quarks in the fundamental representation, quarks in the 2-indice (anti)symmetric representation and quarks in the adjoint representation. The last three ... -
Motor strategies and adiabatic invariants: The case of rhythmic motion in parabolic flights
05 août 2021, CeREF TechniqueArticle scientifiqueThe role of gravity in human motor control is at the same time obvious and difficult to isolate. It can be assessed by performing experiments in variable gravity. We propose that adiabatic invariant theory may be used to reveal nearly conserved quantities in human voluntary rhythmic motion, an individual being seen as a complex time-dependent dynamical system with bounded motion in phase space. ...
