1,351 research outputs found
Comparison of optometric extension program\u27s test #19 to Hofstetter\u27s formulas
This is a study to determine how well Hofstetter\u27s Formulas predict accommodative amplitude in the clinical setting when using the Optometric Extension Program\u27s Test #19 (O.E.P. #19) as the method of measurement. O.E.P. #19 findings were recorded from 150 Pacific University College of Optometry clinic files of patients ages 10 to 60. Scatter grams, regression lines and slope formulas were created to show the age vs accommodative amplitude correlations (see Results and Discussion). The results of my study show that using the Optometric Extension Program\u27s Test #19 method produces accommodative amplitudes that are generally lower than Hofstetter predicts. This leads me to conclude that more suitable formulas need to be established when using the O.E.P. #19 method for assessing accommodative faculity
Bound States in Mildly Curved Layers
It has been shown recently that a nonrelativistic quantum particle
constrained to a hard-wall layer of constant width built over a geodesically
complete simply connected noncompact curved surface can have bound states
provided the surface is not a plane. In this paper we study the weak-coupling
asymptotics of these bound states, i.e. the situation when the surface is a
mildly curved plane. Under suitable assumptions about regularity and decay of
surface curvatures we derive the leading order in the ground-state eigenvalue
expansion. The argument is based on Birman-Schwinger analysis of Schroedinger
operators in a planar hard-wall layer.Comment: LaTeX 2e, 23 page
Energy Conservation Constraints on Multiplicity Correlations in QCD Jets
We compute analytically the effects of energy conservation on the
self-similar structure of parton correlations in QCD jets. The calculations are
performed both in the constant and running coupling cases. It is shown that the
corrections are phenomenologically sizeable. On a theoretical ground, energy
conservation constraints preserve the scaling properties of correlations in QCD
jets beyond the leading log approximation.Comment: 11 pages, latex, 5 figures, .tar.gz version avaliable on
ftp://www.inln.unice.fr
Pulse-driven quantum dynamics beyond the impulsive regime
We review various unitary time-dependent perturbation theories and compare
them formally and numerically. We show that the Kolmogorov-Arnold-Moser
technique performs better owing to both the superexponential character of
correction terms and the possibility to optimize the accuracy of a given level
of approximation which is explored in details here. As an illustration, we
consider a two-level system driven by short pulses beyond the sudden limit.Comment: 15 pages, 5 color figure
Emergence of a confined state in a weakly bent wire
In this paper we use a simple straightforward technique to investigate the
emergence of a bound state in a weakly bent wire. We show that the bend behaves
like an infinitely shallow potential well, and in the limit of small bending
angle and low energy the bend can be presented by a simple 1D delta function
potential.Comment: 4 pages, 3 Postscript figures (uses Revtex); added references and
rewritte
Effet dâun programme dâactivitĂ© physique intermittent de haute intensitĂ© sur la perte de masse grasse abdominale chez la femme DT2 mĂ©nopausĂ©e
Contexte : A la mĂ©nopause, la diminution des taux dâestrogĂšnes favorise un dĂ©pĂŽt de masse grasse (MG) abdominal (sous-cutanĂ© et viscĂ©ral). La MG viscĂ©rale est corrĂ©lĂ©e aux maladies cardio-vasculaires (MCV). Ce risque est accentuĂ© chez les sujets prĂ©sentant un diabĂšte de type 2 (DT2).Objectif : Comparer deux modalitĂ©s dâentraĂźnement, continu de moyenne intensitĂ© (SSE) vs. intermittent de haute intensitĂ© (HIIE), sur la perte de MG abdominale (dont viscĂ©rale) chez des femmes DT2 mĂ©nopausĂ©es.MatĂ©riels et mĂ©thode : Seize femmes DT2 mĂ©nopausĂ©es (69±1ans; IMC : 31±1 kg/mÂČ) ont Ă©tĂ© rĂ©parties alĂ©atoirement en deux groupes. Pendant quatre mois, deux fois par semaine, 8 dâentre elles ont rĂ©alisĂ© un entraĂźnement SSE (40 min de pĂ©dalage Ă 50% de la FCmax de rĂ©serve), et 8 ont rĂ©alisĂ© un entraĂźnement HIIE (8s de sprint suivies de 12s de rĂ©cupĂ©ration active, pendant 20 min). PrĂ© (T0) et post entraĂźnement (T4), la composition corporelle et la MG abdominale totale ont Ă©tĂ© mesurĂ©es par DXA (Dual Energy X-ray Absorptiometry). La MG viscĂ©rale a Ă©tĂ© estimĂ©e Ă partir de la mĂ©thode de Martin et Jensen1. A T0 et T4, les apports Ă©nergĂ©tiques et le niveau dâactivitĂ© physique ont Ă©tĂ© dĂ©terminĂ©s (questionnaires et accĂ©lĂ©romĂštrie validĂ©e2 intĂ©grĂ©e sur smartphone).RĂ©sultats : AprĂšs 16 semaines dâintervention, sans modification des apports Ă©nergĂ©tiques et du niveau dâactivitĂ© physique total, une perte de MG totale et un gain de masse maigre est observĂ© (effet temps, p<0.05). La diminution de MG abdominale est supĂ©rieure dans le groupe HIIE (0.32% ± 2.07 vs 8.32 % ± 2.19, p<0.05) et la perte de MG viscĂ©rale nâest observĂ©e que dans le groupe HIIE (p<0.05).Conclusion : LâentraĂźnement de type HIIE apparait comme un programme alternatif intĂ©ressant chez la femme DT2 mĂ©nopausĂ©e en diminuant significativement la MG abdominale totale et viscĂ©rale
Perturbation of an Eigen-Value from a Dense Point Spectrum : An Example
We study a perturbed Floquet Hamiltonian depending on a coupling
constant . The spectrum is assumed to be pure point and
dense. We pick up an eigen-value, namely , and show the
existence of a function defined on such that
for all , 0 is a point of
density for the set , and the Rayleigh-Schr\"odinger perturbation series
represents an asymptotic series for the function . All ideas
are developed and demonstrated when treating an explicit example but some of
them are expected to have an essentially wider range of application.Comment: Latex, 24 pages, 51
Multiple bound states in scissor-shaped waveguides
We study bound states of the two-dimensional Helmholtz equations with
Dirichlet boundary conditions in an open geometry given by two straight leads
of the same width which cross at an angle . Such a four-terminal
junction with a tunable can realized experimentally if a right-angle
structure is filled by a ferrite. It is known that for there is
one proper bound state and one eigenvalue embedded in the continuum. We show
that the number of eigenvalues becomes larger with increasing asymmetry and the
bound-state energies are increasing as functions of in the interval
. Moreover, states which are sufficiently strongly bent exist in
pairs with a small energy difference and opposite parities. Finally, we discuss
how with increasing the bound states transform into the quasi-bound
states with a complex wave vector.Comment: 6 pages, 6 figure
Poursuite et reconnaissance d'objets dans une séquence infrarouge par contours actifs robustes incrémentaux et réseaux neuronaux
Cet article prĂ©sente une chaĂźne de traitement de sĂ©quences d'images fournies par un senseur infrarouge aĂ©roportĂ©. Il s'agit de pouvoir isoler, poursuivre et identifier un objet Ă partir d'une sĂ©quence d'images, que la cible soit en mouvement ou en dĂ©formation apparente. Lorsque les images sont bruitĂ©es et faiblement contrastĂ©es, les traitements classiques atteignent leurs limites et sont souvent insuffisants. Dans le cadre de notre Ă©tude, la segmentation et la poursuite sont rĂ©alisĂ©es par des contours actifs de type « snake », appelĂ©s snakes robustes. AdaptĂ©s, ils permettent la poursuite dans des conditions difficiles. Dans ce contexte hostile oĂč on ne dispose pas de modĂšle des cibles, la reconnaissance est rĂ©alisĂ©e par un rĂ©seau de neurones Ă partir d'attributs extraits de la segmentation fournie par le snake
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