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Search Results: 1 - 10 of 1047 matches for " PR;Ludewig "
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Scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement
Phadke, V;Camargo, PR;Ludewig, PM;
Brazilian Journal of Physical Therapy , 2009, DOI: 10.1590/S1413-35552009005000012
Abstract: objective: the purpose of this manuscript is to review current knowledge of how muscle activation and force production contribute to shoulder kinematics in healthy subjects and persons with shoulder impingement. results: the middle and lower serratus anterior muscles produce scapular upward rotation, posterior tilting, and external rotation. upper trapezius produces clavicular elevation and retraction. the middle trapezius is primarily a medial stabilizer of the scapula. the lower trapezius assists in medial stabilization and upward rotation of the scapula. the pectoralis minor is aligned to resist normal rotations of the scapula during arm elevation. the rotator cuff is critical to stabilization and prevention of excess superior translation of the humeral head, as well as production of glenohumeral external rotation during arm elevation. alterations in activation amplitude or timing have been identified across various investigations of subjects with shoulder impingement as compared to healthy controls. these include decreased activation of the middle or lower serratus anterior and rotator cuff, delayed activation of middle and lower trapezius, and increased activation of the upper trapezius and middle deltoid in impingement subjects. in addition, subjects with a short resting length of the pectoralis minor exhibit altered scapular kinematic patterns similar to those found in persons with shoulder impingement. conclusion: these normal muscle functional capabilities and alterations in patient populations should be considered when planning exercise approaches for the rehabilitation of these patients.
Scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement Atividade dos músculos escapulares e do manguito rotator durante a eleva o do bra o: uma revis o da fun o normal e das altera es na síndrome do impacto
V Phadke,PR Camargo,PM Ludewig
Brazilian Journal of Physical Therapy , 2009,
Abstract: OBJECTIVE: The purpose of this manuscript is to review current knowledge of how muscle activation and force production contribute to shoulder kinematics in healthy subjects and persons with shoulder impingement. RESULTS: The middle and lower serratus anterior muscles produce scapular upward rotation, posterior tilting, and external rotation. Upper trapezius produces clavicular elevation and retraction. The middle trapezius is primarily a medial stabilizer of the scapula. The lower trapezius assists in medial stabilization and upward rotation of the scapula. The pectoralis minor is aligned to resist normal rotations of the scapula during arm elevation. The rotator cuff is critical to stabilization and prevention of excess superior translation of the humeral head, as well as production of glenohumeral external rotation during arm elevation. Alterations in activation amplitude or timing have been identified across various investigations of subjects with shoulder impingement as compared to healthy controls. These include decreased activation of the middle or lower serratus anterior and rotator cuff, delayed activation of middle and lower trapezius, and increased activation of the upper trapezius and middle deltoid in impingement subjects. In addition, subjects with a short resting length of the pectoralis minor exhibit altered scapular kinematic patterns similar to those found in persons with shoulder impingement. CONCLUSION: These normal muscle functional capabilities and alterations in patient populations should be considered when planning exercise approaches for the rehabilitation of these patients. OBJETIVO: O objetivo deste manuscrito é revisar o conhecimento atual sobre como a ativa o muscular e a produ o de for a contribuem para a cinemática do ombro em indivíduos saudáveis e em pessoas com síndrome do impacto. RESULTADOS: As por es média e inferior do músculo serrátil anterior produzem rota o para cima, inclina o posterior e rota o externa na escápula. O trapézio superior produz eleva o e retra o da clavícula. O trapézio médio é principalmente um estabilizador medial da escápula. O trapézio inferior auxilia na estabiliza o medial e rota o para cima da escápula. O músculo peitoral menor está alinhado para resistir às rota es normais da escápula durante a eleva o do bra o. O manguito rotador é crucial para a estabiliza o e preven o do excesso de transla o superior da cabe a do úmero, assim como para a produ o de rota o externa na glenoumeral durante a eleva o do bra o. Foram identificadas altera es na amplitude ou no tempo de ativa
A Semiclassical Heat Kernel Proof of the Poincaré-Hopf Theorem
Matthias Ludewig
Mathematics , 2013,
Abstract: We treat the Witten operator on the de Rham complex with semiclassical heat kernel methods to derive the Poincar\'e-Hopf theorem and degenerate generalizations of it. Thereby, we see how the semiclassical asymptotics of the Witten heat kernel are related to approaches using the Thom form of Mathai and Quillen.
Vector Fields with a non-degenerate Source
Matthias Ludewig
Mathematics , 2013, DOI: 10.1016/j.geomphys.2014.01.014
Abstract: We discuss the solution theory of operators of the form $\nabla_X + A$, acting on smooth sections of a vector bundle with connection $\nabla$ over a manifold $M$, where $X$ is a vector field having a critical point with positive linearization at some point $p \in M$. As an operator on a suitable space of smooth sections $\Gamma^\infty(U, \V)$, it fulfills a Fredholm alternative, and the same is true for the adjoint operator. Furthermore, we show that the solutions depend smoothly on the data $\nabla$, $X$ and $A$.
Asymptotic eigenfunctions for Schr?dinger operators on a vector bundle
Matthias Ludewig,Elke Rosenberger
Mathematics , 2013,
Abstract: In the limit $\hbar\to 0$, we analyze a class of Schr\"odinger operators $H_\hbar = \hbar^2 L + \hbar W + V\cdot \mathrm{id}_\Eh$ acting on sections of a vector bundle $\Eh$ over a Riemannian manifold $M$ where $L$ is a Laplace type operator, $W$ is an endomorphism field and the potential energy $V$ has a non-degenerate minimum at some point $p\in M$. We construct quasimodes of WKB-type near $p$ for eigenfunctions associated with the low lying eigenvalues of $H_\hbar$. These are obtained from eigenfunctions of the associated harmonic oscillator $H_{p, \hbar}$ at $p$, acting on $C^\infty (T_pM, \Eh_p)$.
Generalization of the Second Order Vector Potential Formulation for Arbitrary Non-Orthogonal Curvilinear Coordinates Systems from the Covariant Form of Maxwell's Equations  [PDF]
Denis Prémel
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.410055
Abstract: A great number of semi-analytical models, notably the representation of electromagnetic fields by integral equations are based on the second order vector potential (SOVP) formalism which introduces two scalar potentials in order to obtain analytical expressions of the electromagnetic fields from the two potentials. However, the scalar decomposition is often known for canonical coordinate systems. This paper aims in introducing a specific SOVP formulation dedicated to arbitrary non-orthogonal curvilinear coordinates systems. The electromagnetic field representation which is derived in this paper constitutes the key stone for the development of semi-analytical models for solving some eddy currents moelling problems and electromagnetic radiation problems considering at least two homogeneous media separated by a rough interface. This SOVP formulation is derived from the tensor formalism and Maxwell’s equations written in a non-orthogonal coordinates system adapted to a surface characterized by a 2D arbitrary aperiodic profile.
Immunopathological Basis of Virus-induced Myocarditis
Reinhard Maier,Philippe Krebs,Burkhard Ludewig
Clinical and Developmental Immunology , 2004, DOI: 10.1080/10446670410001670427
Abstract: Heart diseases are an important cause of morbidity and mortality in industrialized countries. Dilated cardiomyopathy (DCM), one of the most common heart diseases, may be the consequence of infectionassociated myocardits. Coxsackievirus B3 (CVB3) can be frequently detected in the inflamed heart muscle. CVB3-induced acute myocarditis is most likely the consequence of direct virus-induced myocyte damage, whereas chronic CVB3 infection-associated heart disease is dominated by its immunopathological sequelae. Bona fide autoimmunity, for example, directed against cardiac myosin, may favor chronic destructive immune damage in the heart muscle and thereby promote the development of DCM. The immunopathogenesis of myocarditis and subsequent DCM induced either by pathogens or autoantigens can be investigated in well-established animal models. In this article, we review recent studies on the role of viruses, with particular emphasis on CVB3, and different immunological effector mechanisms in initiation and progression of myocarditis.
The genome of the endophytic bacterium H. frisingense GSF30T identifies diverse strategies in the Herbaspirillum genus to interact with plants
Daniel Straub,Anton Hartmann,Uwe Ludewig
Frontiers in Microbiology , 2013, DOI: 10.3389/fmicb.2013.00168
Abstract: The diazotrophic, bacterial endophyte Herbaspirillum frisingense GSF30T has been identified in biomass grasses grown in temperate climate, including the highly nitrogen-efficient grass Miscanthus. Its genome was annotated and compared with related Herbaspirillum species from diverse habitats, including H. seropedicae, and further well-characterized endophytes. The analysis revealed that Herbaspirillum frisingense lacks a type III secretion system that is present in some related Herbaspirillum grass endophytes. Together with the lack of components of the type II secretion system, the genomic inventory indicates distinct interaction scenarios of endophytic Herbaspirillum strains with plants. Differences in respiration, carbon, nitrogen and cell wall metabolism among Herbaspirillum isolates partially correlate with their different habitats. Herbaspirillum frisingense is closely related to strains isolated from the rhizosphere of phragmites and from well water, but these lack nitrogen fixation and metabolism genes. Within grass endophytes, the high diversity in their genomic inventory suggests that even individual plant species provide distinct, highly diverse metabolic niches for successful endophyte-plant associations.
Effect of friction in a toy model of granular compaction
F. Ludewig,S. Dorbolo,N. Vandewalle
Physics , 2004, DOI: 10.1103/PhysRevE.70.051304
Abstract: We proposed a toy model of granular compaction which includes some resistance due to granular arches. In this model, the solid/solid friction of contacting grains is a key parameter and a slipping threshold Wc is defined. Realistic compaction behaviors have been obtained. Two regimes separated by a critical point Wc* of the slipping threshold have been emphasized : (i) a slow compaction with lots of paralyzed regions, and (ii) an inverse logarithmic dynamics with a power law scaling of grain mobility. Below the critical point Wc*, the physical properties of this frozen system become independent of Wc. Above the critical point Wc*, i.e. for low friction values, the packing properties behave as described by the classical Janssen theory for silos.
Bouncing trimer: a random self-propelled particle, chaos and periodical motions
S. Dorbolo,F. Ludewig,N. Vandewalle
Physics , 2008, DOI: 10.1088/1367-2630/11/3/033016
Abstract: A trimer is an object composed of three centimetrical stainless steel beads equally distant and is predestined to show richer behaviours than the bouncing ball or the bouncing dimer. The rigid trimer has been placed on a plate of a electromagnetic shaker and has been vertically vibrated according to a sinusoidal signal. The horizontal translational and rotational motions of the trimer have been recorded for a range of frequencies between 25 and 100 Hz while the amplitude of the forcing vibration was tuned for obtaining maximal acceleration of the plate up to 10 times the gravity. Several modes have been detected like e.g. rotational and pure translational motions. These modes are found at determined accelerations of the plate and do not depend on the frequency. By recording the time delays between two successive contacts when the frequency and the amplitude are fixed, a mapping of the bouncing regime has been constructed and compared to that of the dimer and the bouncing ball. Period-2 and period-3 orbits have been experimentally observed. In these modes, according to observations, the contact between the trimer and the plate is persistent between two successive jumps. This persistence erases the memory of the jump preceding the contact. A model is proposed and allows to explain the values of the particular accelerations for which period-2 and period-3 modes are observed. Finally, numerical simulations allow to reproduce the experimental results. That allows to conclude that the friction between the beads and the plate is the major dissipative process.
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