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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Immediate Effect of Rhythm on the Timing of Upper Extremity Movements in Patients with Parkinson's Disease

Keenan, Erin Mary 01 June 2011 (has links)
Parkinson’s disease is a neurodegenerative disease caused by a loss of dopamine-producing neurons in the basal ganglia. Primary motor deficits include resting tremor, bradykinesia, muscular rigidity, and postural instability. Most importantly, patients have difficulty both initiating movements and performing well-timed movements. This study explored the effect of rhythm on the timing of upper extremity movements in patients with Parkinson’s disease. Comparisons were made between an external rhythmic cue, an external rhythmic cue in combination with auditory feedback, and no cue. Fifteen participants performed a simple reaching task in each of the four cueing conditions with the use of an interactive touch table. Condition 1 consisted of no cue. Condition 2 included a metronome set to the participant’s baseline tempo. Condition 3 included a metronome set to the participant’s baseline tempo, and a synthesized tone that occurred as a result of contact with the table. Finally, Condition 4 included no cue, similar to Condition 1. Participants were placed into either a mild/moderate level of impairment group, or a severe level of impairment group. Data were collected for total movement time, initiation time, and delta time for each participant in all four conditions. Results of the study did not reveal a main effect of condition on total movement time, initiation time or delta time. However, post-hoc pair-wise comparisons revealed significant decreases between Condition 1 and Condition 4, which were both uncued conditions, for both total movement time and delta time. In addition, for total movement time, a significant decrease was found between Condition 2 (external rhythmic cue) and Condition 4 (no cue). An immediate effect of cueing was found for initiation time and delta time, but did not reach a level of significance. An immediate effect of cueing on total movement time was not evident. Overall, from Condition 1 to Condition 2 as well as Condition 1 to Condition 3, initiation time and delta time decreased, but total movement time did not. Further analysis of level of impairment could not be conducted because of the small number of participants in the severe level of impairment group. The results suggest that one auditory cue was not more beneficial than the other for improving total movement time, initiation time, or delta time. In addition, the improvement from Condition 1 to Condition 4 for total movement time and delta time suggests that a practice effect was evident for the participants. The results of the study suggest that long-term training of either auditory cue can be an effective rehabilitation technique for patients with Parkinson’s disease to improve the timing of upper extremity movements.
2

Physical aspects and modelling of turbulent MILD combustion

Minamoto, Yuki January 2014 (has links)
Moderate or Intense Low-oxygen Dilution (MILD) combustion is one of combustion technologies which can improve efficiency and reduce emissions simultaneously. This combustion type is characterised by the highly preheated reactant temperature and the relatively small temperature rise during combustion due to the intense dilution of the reactant mixture. These unique combustion conditions give MILD combustion very attractive features such as high combustion efficiency, reduction of pollutant emissions, attenuation of combustion instabilities and flexibility of the flow field. However, our understanding of MILD combustion is not enough to employ the MILD combustion technology further for modern combustion devices. In this thesis, Direct Numerical Simulation (DNS) has been carried out for turbulent MILD combustion under four MILD and classical premixed conditions. A two-phase strategy is employed in the DNS to include the effect of imperfect mixing between fresh and exhaust gases before intense chemical reactions start. In the simulated instantaneous MILD reaction rate fields, both thin and distributed reaction zones are observed. Thin reaction zones having flamelet like characteristics propagate until colliding with other thin reaction zones to produce distributed reaction zones. Also, the effect of such interacting reaction zones on scalar gradient has to be taken into account in flamelet approaches. Morphological features of MILD reaction zones are investigated by employing Minkowski functionals and shapefinders. Although a few local reaction zones are classified as thin shape, the majority of local reaction zones have pancake or tube-like shapes. The representative scales computed by the shapefinders also show a typical volume where intense reactions appear. Given high temperature and existence of radicals in the diluted reactants, both reaction dominated and flame-propagation dominated regions are locally observed. These two phenomena are closely entangled under a high dilution condition. The favourable conditions for these phenomena are investigated by focusing on scalar fluxes and reaction rate. A conditional Probability Density Function (PDF) is proposed to investigate flamelet/non-flamelet characteristics of MILD combustion. The PDF can be obtained by both numerically and experimentally. The PDF shows that MILD combustion still has the direct relationship between reaction rate and scalar gradient, although the tendency is statistically weak due to the distributed nature of MILD reaction zones. Finally, based on the physical aspects of MILD combustion explained in this work, a representative model reactor for MILD combustion is developed. The model reactor is also used in conjunction with the presumed PDF for a mean and filtered reaction rate closure. The results show a good agreement between the modelled reaction rate and the DNS results.
3

The Effect of Explicit Timing on Math Performance Using Interspersal Assignments with Students with Mild/Moderate Disabilities

Hou, Fangjuan 01 May 2010 (has links)
Explicit timing and interspersal assignments have been validated as effective methods to facilitate students' math practice. However, no researchers have explored the combinative effect of these two methods. In Study 1, we extended the literature by comparing the effect of explicit timing with interspersal assignments, and interspersal assignments without timing. Generally, participants' rate of digits correct on easy and hard addition problems was higher during the explicit timing condition than during the untimed condition. However, the participants' rate of digits correct decreased after initial implementation of the explicit timing condition. Motivation plays a crucial role in maintaining performance levels and helping students make continuous progress. Preferred reinforcers and setting academic targets have been widely utilized as active motivational components to increase the likelihood of a successful strategy in school settings. In Study 2, we employed a brief MSWO reinforcer assessment to identify individual student's low- and high-preference reinforcers and examined the effects of explicit timing on interspersed assignments combined with high preference or low preference reinforcers, and setting academic targets. In general, explicit timing combined with preferred reinforcers and academic targets produced a more sustainable effect on participants' rate of digits correct than explicit timing alone. In addition, high-preference reinforcers were more effective than low-preference reinforcers for three of five participants. For two participants, an increasing trend was observed when low preference reinforcers were contingent on meeting academic targets. These results are discussed relative to using preference assessments with students with mild/moderate disabilities.
4

Évaluation du remodelage des voies respiratoires centrales de chevaux asthmatiques légers/modérés

Bessonnat, Amandine 08 1900 (has links)
No description available.
5

1,3-Dipolare Cycloaddition von N2O an hochreaktive Mehrfachbindungen

Plefka, Oliver 16 June 2011 (has links)
In der vorliegenden Arbeit wird über 1,3-dipolare Cycloadditionen mit Lachgas (N2O) unter milden Reaktionstemperaturen (≈ RT) berichtet. N2O ist ein sehr unreaktives 1,3-dipolares Reagenz. Bisher in der Literatur durchgeführte 1,3-dipolare Cycloadditionen mit N2O benötigten immer sehr drastische und gefährliche Reaktionsbedingungen (bis zu 300°C und 500 atm.). Dabei entstanden nach einer (postulierten) einleitenden 1,3-dipolaren Cycloaddition von N2O an Olefine oder Alkine immer nur stickstofffreie Reaktionsprodukte. Durch den Einsatz von hochreaktiven Cycloalkinen als 1,3-Dipolarophile konnten erstmals 1,3-dipolare Cycloadditionen mit N2O bei deutlich milderen Bedingungen (–25°C bis +60°C) als den bisher bekannten durchgeführt werden. Dabei war es mit Cyclooctin und Cycloocten-5-in erstmals möglich, stabile und vollständig charakterisierbare Reaktionsprodukte zu erhalten, die alle drei Atome des addierten N2O-Moleküls enthalten. Mit 4,5-Didehydro-2,3,6,7-tetrahydro-3,3,6,6-tetramethylthiepin konnte sogar erstmals ein alpha-Diazoketon durch 1,3-dipolare Cycloaddition von N2O erhalten und dieses bei –25°C NMR-spektroskopisch untersucht werden. Diese alpha-Diazoketone entstehen aus der elektrocyclischen Ringöffnung der entsprechenden 1,2,3-Oxadiazole welche aus der Cycloaddition von N2O und dem eingesetzten Cycloalkin stammen. Mit alpha-substituierten Cyclooctinen konnten auch 1,3-dipolare Cycloadditionen mit N2O bei milden Temperaturen durchgeführt werden, um stickstofffreie Reaktionsprodukte zu erhalten.

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