Previous studies have demonstrated that the magnitudes of otoacoustic emissions (OAEs) measured during behavioral tasks requiring attention were different from OAE magnitudes measured during tasks that did not require attention. The implication of these results is that the cognitive and perceptual demands of a task can affect the first neural stage of auditory processing—the sensory receptors themselves. However, the directions of the reported attentional effects have been inconsistent, the magnitudes of the observed differences always have been small, and comparisons across studies have been made difficult by significant procedural differences. In this study, we used a nonlinear version of the stimulus-frequency OAE (SFOAE), called the nSFOAE, to measure cochlear responses from human subjects while they simultaneously performed behavioral tasks requiring selective auditory attention (dichotic or diotic listening), or relative inattention. The results indicated statistically significant systematic differences in nSFOAE magnitudes within subjects, but opposite directions of effect across subjects. Differences in the nSFOAEs measured during the dichotic- and diotic-listening conditions suggested that cochlear responses differed in these two types of selective-listening tasks. Time constants measured from functions fitted to the nSFOAE responses indicated faster efferent effects during selective listening than during inattentive listening for the majority of subjects. Furthermore, measurements in brief silent intervals after the nSFOAE stimuli indicated weaker residual nSFOAE magnitudes during selective listening than during inattentive listening for every subject. This collection of findings supports the hypothesis that auditory attentional demands can modulate cochlear processing, presumably to the benefit of the listener. / text

Ventilator-associated pneumonia (VAP) is a serious complication in critically ill patients; it can prolong intubation, increase intensive care unit and hospital length of stay, and increase mortality to twice the level of patients who do not develop VAP. The purpose of this project was to determine the effect of an evidence-based educational program to prevent VAP on ICU nurses' actual and documented practices for preventing VAP. The research questions addressed whether an educational program focused on VAP prevention will affect critical care nurses' compliance with a VAP prevention bundle, and whether the education will result in maintenance of a rate of zero cases of VAP per 1000 ventilator days. Data will be collected from all ICU patients intubated more than 24 hours and will include: (a) the frequency of oral care, (b) head-of-bed elevation of 30â??45 degrees, (c) daily sedation vacation, (d) assessment of readiness for extubation, and (e) whether prophylaxis for deep vein thrombosis and for peptic ulcer disease was ordered. Observations of care will verify the accuracy of nurses' documentation in the medical record. A survey will assess nurse satisfaction with the educational program. Paired t tests will be used to compare the compliance of the nurses with each element of oral care and hygiene practices before and after the intervention. Analysis of variance will be calculated on the mean duration of ventilation, mean ICU and hospital length of stay, mortality before discharge, patient acuity, and rates of VAP per 1000 ventilator days. The goal of this project is a compliance rate of 90% or greater with the elements of the VAP prevention bundle, leading to decreased ventilator and ICU days, decreased morbidity, decreased mortality, and lower emotional distress. Positive social change will be accomplished through an immediate improvement in the lives of VAP-prone individuals.

In a pressurized water reactor (PWR), pressurized water flows over fuel rods containing radioactive uranium. Potential failure of these nuclear fuel rods is a primary concern, as fuel rod failure typically results in power generation losses and reactor downtime. Thermal parameters such as critical heat flux have traditionally been utilized as performance metrics to ensure that the reactor core remains stable even during failure events. Recently, fuel leaking events have occurred which have resulted in excess debris buildup on fuel rods and fuel grid array mixing devices. Understanding the flow field surrounding these nuclear fuel rods is critical in predicting where crud could deposit. Although CFD simulations have been conducted to characterize the fluid flow around fuel rod bundles, limited experimental data characterizing the mechanics of this fluid flow exists in the current literature. This study will present experimental data collected detailing the fluid flow around a rod bundle geometry using a novel matched refractive index particle tracking velocimetry (PTV) technique over a 3D volume cross section of a prototypical nuclear fuel rod bundle. Velocimetry tracking will be performed in order to characterize the mechanics of the fluid flow. Using optical distortion mitigation techniques and various image processing methods, data from multiple cameras was used to assemble 3-dimensional velocity information of a turbulent fluid region. Results are compared to the solution of a k-epsilon unsteady RANS numerical simulation.

Reduction theory for systems with symmetry deals with the problem of understanding dynamics on a manifold with an action of a Lie group. In geometric mechanics, this problem can be formulated in the Lagrangian, Hamiltonian or affine connection frameworks. While the Lagrangian and Hamiltonian formulations have been well developed, the results obtained in these setups are based on variational principles and symplectic geometry. These methods cannot be used directly in the affine connection formulation unless additional structure is available. In this thesis, a manifold with an arbitrary affine connection is considered, and the geodesic spray associated with the connection is studied in the presence of a Lie group action. In particular, results are obtained that provide insight into the structure of the reduced dynamics associated with the given invariant affine connection. The geometry of the frame bundle of the given manifold is used to provide an intrinsic description of the geodesic spray. A fundamental relationship between the geodesic spray, the tangent lift and the vertical lift of the symmetric product is obtained, which provides a key to understanding reduction in this formulation. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2007-07-24 01:00:05.635

archives@tulane.edu / This thesis examines the geometry and combinatorics of Borel subgroup orbits in classical symmetric spaces G/L where G is complex linear algebraic group and L is a Levi factor of a maximal parabolic subgroup P in G. In these cases, known as symmetric spaces of Hermitian type, we show that the canonical projection map $\pi : G/L \to G/P$ has the structure of an affine bundle. This fact yields a cell decomposition of G/L as well as isomorphisms of the cohomology and Chow rings of G/L and G/P, and motivates the study of the Borel orbits of G/L in relation to their images under the equivariant map $\pi$. For all of the cases of interest (symmetric spaces of types AIII, CI, DIII and BDI), G/P is a Grassmannian variety with Borel orbits called Schubert cells. Borel orbits of most of these symmetric spaces are parametrized by combinatorial objects called clans. This thesis provides enumerative formulae for the orbits in type CI, DIII and BDI , and gives bijections between sets of clans and other families of objects such as (fixed-point free) partial involutions, rook placements, and set partitions. Clans come with a poset structure given by the closure containment relation of the corresponding Borel orbits, and we supply rank polynomials for these posets in types CI and DIII. We give a combinatorial description of the closure order relations in types AIII, CI, and DIII which allows us to resolve part of a conjecture of Wyser on the restriction of this order from type AIII to other types. In the course of this description, we identify the preimages of Schubert cells under the map \pi as collections of clans called “sects.” Our combinatorial description of the sects identifies Borel orbits whose closures generate the Chow ring of G/L and reveals additional structure in the closure poset of clans. In particular, the preimage of the largest Schubert cell coincides variously with well-known posets of matrix Schubert varieties and congruence Borel orbit closures. Furthermore, we show that in type AIII the closure order restricted to a given sect can be described combinatorially in terms of “rank tableaux.” / 0 / Aram Bingham

<p> The aim of this thesis is to construct some smooth Einstein manifolds with nonzero Einstein constant, and then to investigate their topological and geometric properties.</p> <p> In the negative case, we are able to construct conformally compact Einstein metrics on 1. products of an arbitrary closed Einstein manifold and a certain even-dimensional ball bundle over products of Hodge Kähler-Einstein manifolds, 2. certain solid torus bundles over a single Fano Kähler-Einstein manifold. We compute the associated conformal invariants, i.e., the renormalized volume in even dimensions and the conformal anomaly in odd dimensions. As by-products, we obtain many Riemannian manifolds with vanishing Q-curvature.</p> <p> In the positive case, we are able to construct complete Einstein metrics on certain 3-sphere bundles over a Fano Kähler-Einstein manifold. We classify the homeomorphism and diffeomorphism types of the total spaces when the base manifold is the complex projective plane.</p> / Thesis / Doctor of Philosophy (PhD)

The inner ear contains cells with ciliary bundles that have been identified as sites of mechanoelectrical transduction; they take a mechanical stimuli and convert it to an electrical response. The ciliary bundles vary structurally within the organs of the inner ear; this structural difference may play a role in the mechanical properties of each bundle. A relationship between the structure and the mechanics of the ciliary bundle can be found by studying structurally diverse bundles. To explore this relationship, a system was designed to mechanically stimulate the ciliary bundles in normal physiological range and measure their displacement. An extrinsic Fabry-Perot interferometer (EFPI) was developed to measure the response of a ciliary bundle that is subjected to a force applied by a glass whisker. 'Imitation bundles', similar in stiffness to living ciliary bundles, were made to test the system. The stiffness of an 'imitation bundle' was first determined by suspending styrene beads from its tip and optically measuring the resultant displacement. Then the EFPI was also used to determine the stiffness. The EFPI compared well to the stiffness found using the styrene beads; the largest difference between the two methods was 130/0. The EFPI was also tested in water to ensure its operation in the tissue environment; this test was successful in that it was able to measure displacements in a bundle's normal physiological range. With both of the tests showing good results, we conclude that our system can be used to measure the stiffness of the ciliary bundles located in the inner ear. / Master of Science

The aim of this thesis is to analyse high-frequency ECG to detect some heart diseases. This is performed with averaging of selected QRS complexes for each lead of the signal; these are thenfilteredin range 500-1 000 Hz. After that the envelope of the signal is done and here the peaks are detected. Based on mutual positions of this peaks, it is possible to detectwhat kind od signal we treat.

The aim of this thesis is to analyse high-frequency ECG to detect some heart diseases. This is performed with averaging of selected QRS complexes for each lead of the signal; these are then filtered in range 500-1 000 Hz. After that the envelope of the signal is done and here the peaks are detected. Based on mutual positions of this peaks, it is possible to detect what kind od signal we treat.

No description available.