Global ETD Search

101	Impact d’une sieste sur plasticité cérébrale induite par stimulation magnétique transcrânienne Sekerovic, Zoran 09 1900 (has links) Chez l’humain, différents protocoles de stimulation magnétique transcrânienne répétée (SMTr) peuvent être utilisés afin de manipuler expérimentalement la plasticité cérébrale au niveau du cortex moteur primaire (M1). Ces techniques ont permis de mieux comprendre le rôle du sommeil dans la régulation de la plasticité cérébrale. Récemment, une étude a montré que lorsqu’une première session de stimulation SMTr au niveau de M1 est suivie d’une nuit de sommeil, l’induction subséquente de la plasticité par une deuxième session SMTr est augmentée. La présente étude a investigué si ce type de métaplasticité pouvait également bénéficier d’une sieste diurne. Quatorze sujets en santé ont reçu deux sessions de intermittent theta burst stimulation (iTBS) connue pour son effet facilitateur sur l’excitabilité corticale. Les sessions de stimulation étaient séparées par une sieste de 90 minutes ou par une période équivalente d’éveil. L’excitabilité corticale était quantifiée en terme d’amplitude des potentiels évoqués moteurs (PEM) mesurés avant et après chaque session de iTBS. Les résultats montrent que la iTBS n’est pas parvenue à augmenter de manière robuste l’amplitude des PEMs lors de la première session de stimulation. Lors de la deuxième session de stimulation, la iTBS a produit des changements plastiques variables et ce peu importe si les sujets ont dormi ou pas. Les effets de la iTBS sur l’excitabilité corticale étaient marqués par une importante variabilité inter et intra-individuelle dont les possibles causes sont discutées. / In humans, various repetitive transcranial magnetic stimulation (rTMS) protocols can be used to modulate motor cortical plasticity. These techniques have shed light on the role of sleep in neural plasticity regulation. Recent work has demonstrated that when a night of sleep follows one session of rTMS over the hand motor cortex (M1), the capacity to induce subsequent plasticity by another rTMS session in M1 is enhanced. The present study investigated whether such metaplasticity could also benefit from a day nap. Fourteen healthy participants received two sessions of intermittent theta burst stimulation (iTBS) known for its excitatory effects on cortical excitability over M1 spaced by either a 90-minute nap or an equivalent amount of wake. Motor cortical excitability was measured in terms of amplitude of motor evoked potentials (MEP), which were assessed before iTBS and after the stimulation. Results show that the first iTBS session did not induce significant change in MEP amplitude. The second iTBS session induced variable plastic changes regardless of whether participants slept or stayed awake. The effects of iTBS on motor cortical excitability were highly variable within and between individuals. The possible causes of such variability are discussed. Plasticité cérébrale Sommeil Sieste Theta burst stimulation (TBS) Métaplasticité Variabilité Humain Plasticity Sleep Nap Transcranial magnetic stimulation (TMS) Metaplasticity Variability Human
102	Impact d’une sieste sur plasticité cérébrale induite par stimulation magnétique transcrânienne Sekerovic, Zoran 09 1900 (has links) Chez l’humain, différents protocoles de stimulation magnétique transcrânienne répétée (SMTr) peuvent être utilisés afin de manipuler expérimentalement la plasticité cérébrale au niveau du cortex moteur primaire (M1). Ces techniques ont permis de mieux comprendre le rôle du sommeil dans la régulation de la plasticité cérébrale. Récemment, une étude a montré que lorsqu’une première session de stimulation SMTr au niveau de M1 est suivie d’une nuit de sommeil, l’induction subséquente de la plasticité par une deuxième session SMTr est augmentée. La présente étude a investigué si ce type de métaplasticité pouvait également bénéficier d’une sieste diurne. Quatorze sujets en santé ont reçu deux sessions de intermittent theta burst stimulation (iTBS) connue pour son effet facilitateur sur l’excitabilité corticale. Les sessions de stimulation étaient séparées par une sieste de 90 minutes ou par une période équivalente d’éveil. L’excitabilité corticale était quantifiée en terme d’amplitude des potentiels évoqués moteurs (PEM) mesurés avant et après chaque session de iTBS. Les résultats montrent que la iTBS n’est pas parvenue à augmenter de manière robuste l’amplitude des PEMs lors de la première session de stimulation. Lors de la deuxième session de stimulation, la iTBS a produit des changements plastiques variables et ce peu importe si les sujets ont dormi ou pas. Les effets de la iTBS sur l’excitabilité corticale étaient marqués par une importante variabilité inter et intra-individuelle dont les possibles causes sont discutées. / In humans, various repetitive transcranial magnetic stimulation (rTMS) protocols can be used to modulate motor cortical plasticity. These techniques have shed light on the role of sleep in neural plasticity regulation. Recent work has demonstrated that when a night of sleep follows one session of rTMS over the hand motor cortex (M1), the capacity to induce subsequent plasticity by another rTMS session in M1 is enhanced. The present study investigated whether such metaplasticity could also benefit from a day nap. Fourteen healthy participants received two sessions of intermittent theta burst stimulation (iTBS) known for its excitatory effects on cortical excitability over M1 spaced by either a 90-minute nap or an equivalent amount of wake. Motor cortical excitability was measured in terms of amplitude of motor evoked potentials (MEP), which were assessed before iTBS and after the stimulation. Results show that the first iTBS session did not induce significant change in MEP amplitude. The second iTBS session induced variable plastic changes regardless of whether participants slept or stayed awake. The effects of iTBS on motor cortical excitability were highly variable within and between individuals. The possible causes of such variability are discussed. Plasticité cérébrale Sommeil Sieste Theta burst stimulation (TBS) Métaplasticité Variabilité Humain Plasticity Sleep Nap Transcranial magnetic stimulation (TMS) Metaplasticity Variability Human
103	Interaction toxine-cellule étudiée par imagerie de nanoémetteurs individuels Turkcan, Silvan 07 December 2010 (has links) (PDF) La membrane cellulaire est une partie vitale de la cellule dont l'architecture joue un rˆole crucial dans de nombreux processus cellulaires, comme la signalisation et le trafic, et dans diverses pathologies. Cette th'ese vise 'a sonder l'architecture membranaire via le mouvement de deux r'ecepteurs membranaires qui sont exploit'es par des toxines bact'eriennes. Les progr'es r'ecents des techniques de microscopie optique ont montr'e que certains r'ecepteurs membranaires ne diffusent pas librement dans la membrane, mais sont confin'es ou diffusent de fa¸con anomale. Actuellement, plusieurs mod'eles con- courent pour expliquer le confinement des r'ecepteurs, tel que le mod'e le Picket-Fence, les radeaux lipidiques et les agr'egats de prot'eines. Pour sonder la membrane, des nanoparticules (Y0.6Eu0.4VO4) dop'ees avec des lan- thanides sont coupl'ees 'a deux toxines peptidiques diff'erentes formant des pores dans la membrane, la toxine α de C. septicum et la toxine ǫ de C. perfingens. Le suivi de r'ecepteurs individuels sur lesquels sont fix'ees des toxines marqu'ees dans la mem- brane apicale de cellules MDCK avec un microscope 'a champ large permet de d'etecter le mouvement du r'ecepteur avec une r'esolution meilleure que la limite de diffrac- tion. Les r'ecepteurs de la toxine α et ǫ montrent une diffusion confin'ee avec des coefficients de diffusion similaires de 0.16 ± 0.14 µm2/s dans des domaines stables de 0.5 µm2. Pour analyser les trajectoires des r'ecepteurs, nous avons mis en oeuvre une nouvelle technique bas'ee sur une m'ethode d'inf'erence. Notre seule hypoth'ese est que le r'ecepteur se d'eplace selon l''equation de Langevin. Cette m'ethode exploite l'ensemble de l'information stock'ee dans la trajectoire et la qualit'e des valeurs extraites est v'erifi'ee par des simulations. Les deux r'ecepteurs sont confin'es dans un potentiel de type ressort avec une raideur de 0.45 pN/µm. Des exp'eriences apr'es d'epl'etion du cholest'erol par la cholest'erol oxydase et apr'es la d'epolym'erisation du cytosquelette par latrunculin B montrent que le confinement des r'ecepteurs individuels d'epend du taux de cholest'erol et que la d'epolym'erisation de l'actine n'influence pas le confinement. En utilisant la nanoparticule coupl'ee aux toxines comme un amplificateur de la force hydrodynamique applique'e par un flux liquide, nous avons mesur'e la r'eponse du r'ecepteur 'a une force ext'erieure. Les r'esultats indiquent une fixation des domaines de confinement sur le cy- tosquelette. Enfin, un mod'ele pour le confinement du r'ecepteur est propos'e, bas'e sur le couplage hydrophobe entre le r'ecepteur et la bicouche lipidique qui l'entoure. Ce mod'ele permet d'expliquer le potentiel de type ressort 'a l'int'erieur du domaine de confinement. [PHYS] Physics [SDV:BC] Life Sciences/Cellular Biology Suivi de molécules uniques (SMT) toxines recepteur architecture membranaire microscopie fluorescence suivi de particules uniques (SPT) microscopie vidéo radeaux lipidiques agrégats de protéines couplage hydrophobe
104	Strengthening the heart of an SMT-solver : Design and implementation of efficient decision procedures Iguernelala, Mohamed 10 June 2013 (has links) (PDF) This thesis tackles the problem of automatically proving the validity of mathematical formulas generated by program verification tools. In particular, it focuses on Satisfiability Modulo Theories (SMT): a young research topic that has seen great advances during the last decade. The solvers of this family have various applications in hardware design, program verification, model checking, etc.SMT solvers offer a good compromise between expressiveness and efficiency. They rely on a tight cooperation between a SAT solver and a combination of decision procedures for specific theories, such as the free theory of equality with uninterpreted symbols, linear arithmetic over integers and rationals, or the theory of arrays.This thesis aims at improving the efficiency and the expressiveness of the Alt-Ergo SMT solver. For that, we designed a new decision procedure for the theory of linear integer arithmetic. This procedure is inspired by Fourier-Motzkin's method, but it uses a rational simplex to perform computations in practice. We have also designed a new combination framework, capable of reasoning in the union of the free theory of equality, the AC theory of associative and commutativesymbols, and an arbitrary signature-disjoint Shostak theory. This framework is a modular and non-intrusive extension of the ground AC completion procedure with the given Shostak theory. In addition, we have extended Alt-Ergo with existing decision procedures to integrate additional interesting theories, such as the theory of enumerated data types and the theory of arrays. Finally, we have explored preprocessing techniques for formulas simplification as well as the enhancement of Alt-Ergo's SAT solver. [INFO:INFO_OH] Computer Science/Other [INFO:INFO_OH] Informatique/Autre Satisfiability Modulo Theories SMT solvers Decision procedures Combination of decision procedures Shostak Associativity and commutativity Rewriting AC-completion Linear integer arithmetic Simplex Fourier-Motzkin
105	The management of teacher-occupational stress at primary schools in Sedibeng District 8, Gauteng Province Matla, Shabe Jonas 06 1900 (has links) This study aimed at establishing the role played by school management teams in managing teacher-occupational-stress in Sedibeng West District primary schools in the Gauteng province. The investigation was conducted using a quantitative research approach. The changes in South African schools’ curriculum which did not have a life span of ten years post-apartheid; the rate of absenteeism pointed out by the Minister of Basic Education Angie Motshega. She believed that these may be caused by serious illness; therefore it impressed the idea of investigating the role played by school management teams in managing teacher-occupational stress. The study looks at the following two research questions:  What are the causes of teacher-occupational-stress?  What role can the school management teams play in managing teacher-occupational-stress? A questionnaire was used as an instrument of data collection from primary schools in Sedibeng West district 8 in the Gauteng province. The researcher’s sample size was 32 (n=32). Findings were that the school management teams are playing their roles and supporting teachers. However, teachers find their teaching job to be stressful. The study found significant factors causing teacher-occupational-stress. One of the factors is failure by the school management team to acknowledge teachers hard work. Recommendations are outlined at the end of this study indicating how the Department of Basic Education can intervene and what the school management teams can do to manage teacher occupational stress. / Educational Leadership and Management Stress School Management Team (SMT) Teacher HOD Learner 372.110019
106	Vision of excellence in secondary schools leadership in Ekurhuleni East District Mngomezulu, Mishack 06 1900 (has links) This research investigates the vision of excellence in secondary schools leadership in Ekurhuleni East District (Gauteng East District) and the existence of a vision of excellence in schools. A literature study investigated models of leadership related to vision of excellence and aspects of vision of excellence in school leadership. An empirical investigation used both a quantitative and qualitative research design to collect data from a purposefully selected and stratified sample of participants and secondary schools in the Ekurhuleni East District (Gauteng East Education District). A questionnaire and focus group interviews were used to gather data from the respondents. Data were analysed and interpreted using quantitative and qualitative approach. The findings of both the literature study and the empirical research on the above-mentioned vision of excellence in secondary schools leadership in Ekurhuleni East District revealed that there is a lack of support from school leadership and the School Management Team (SMT) in realising a vision of excellence in secondary schools leadership. The main challenges that were identified by qualitative method were the lack of support by both the district office and school management or school leadership. The realisation of the vision of excellence is dependent on how the information is managed and disseminated by the school leadership, principals and SMTs. It appears that the realisation of the vision of excellence would enhance the level of understanding of new developments in the education system including the curriculum change and technological advancement. / Educational Leadership and Management / M. Ed. (Education Management) Vision of excellence School leadership School governing body (SGB) School management team (SMT) Vision Excellence Leadership Academic performance Principal 373.120110968224
107	Opravy DPS s BGA a FC pouzdry / PCBs Repairs with BGA and FC Packages Buřival, Tomáš January 2009 (has links) Graduation thesis is specialized on dilemma of the integrated circuits with ball grid array. Chapter two describes several types of packages and confrontation of their characteristics. Chapter three considers possibilities of corrections these boards bedded with packages, mounting and demounting of these packages, method of camera control and also inspection of the soldering process. Chapter four attend to practical measuring of thermal profiles and their optimalization.
108	Bezdrátová čidla pro měření hladiny vody / Wireless water level sensors Pospíšil, Jakub January 2010 (has links) The thesis deals with both scheme and its implementation of water-level metering apparatus. This data are send wireless into 500 m distant station. Potential ways of solution are gradually studied and final design suggested. Detailed implementation methods are described in the following section. Ultrasonic sensors are employed for level measurement and controlling element is processor ATmega162, data are transmitted by transceiver RC1280HP. Apparatus is suggested with a view to the lowest power consumption considering it will be supplied only with a accumulator. Solving of accepting station is not a part of the thesis. Functional tested sample is understated in the execution section.
109	Finns det evidens för att höghastighetsmanipulation av nacken kan orsaka stroke? / Is there evidence that high velocity manipulation of the cervical spine can cause stroke? Eriksson, Andreas January 2020 (has links) Höghastighetsmanipulation av nacken är en manuell behandlingsteknik mot smärta i framförallt nacken och skuldrorna. Tekniken har enligt flera källor visats hänga samman med risken för att drabbas av skador på de kärl som försörjer hjärnan med blod, med bland annat stroke som följd. Andra källor har å andra sidan visat att de är en teknik som är säker att utföra. Den här litteraturstudien har sammanställt och utvärderat forskning som på olika sätt söker utreda om det påstådda sambandet är kausalt eller inte. Metoden som valdes var att genom en av SBU färdigställd mall värdera forskningsartiklar och sedan sortera dem efter relevans, för att på så sätt avgöra huruvida sambandet kan ses som kausalt eller inte. Studieresultatet visade att frågan är för komplex för att kunna besvaras i en enskild studie, och att mer forskning behövs inom flera delområden innan frågan kan besvaras fullt ut. Orsaken till detta är att det finns flera orsaksmekanismer, och flera riskgrupper, för denna typ av skada, där flera ännu är okända. Detta gör att en fullständig kartläggning av samband i frågan ännu inte är möjlig. Däremot är det sannolikt att tekniken kan verka som en utlösande faktor, en trigger, hos vissa personer i riskgrupperna. Därför kan det sägas finnas en risk med tekniken rent praktiskt, oavsett om ett kausalt samband mellan tekniken och stroke i sig existerar eller inte. / High Velocity Manipulation of the cervical spine is a manual treatment technique against pain in foremost the neck, shoulders. The technique has according to multiple sources been connected to the risk of injury to the blood vessels that supply the brain with blood, with among others stroke as a consequence. Other sources have on the other hand shown it the technique to be safe to perform. This literature study has compiled and evaluated research that in various ways tries to find out if said connection is causal The method used was to evaluate articles through a pre-made form from SBU, and then to sort them according to relevance to see if the connection is causal or not. The result showed that the question is too complex to be answered in a single study, and that more research is needed to answer the question in full. This is due to the fact that there are multiple mechanisms behinds this form om injury, that the risk seems to exists in certain groups, and that some of these are not yet identifiable. On the other hand there is a high probability that the technique might act as an activating factor in these groups. Because of this there can be said that a risk exists with the technique in practice, no matter if there is a casual connection between the technique and stroke in itself or not. Chiropraktor physioterapeut manipulation stroke vertebral artery carotid artery cervical spinal manipulation therapy SMT High Velocity Low Amplitude Manipulation HVLA Orthopedic Manual Therapy OMT cerebrovascular dissection CVD vertebral arterial dissection VAD CAD CeAD cerebrovascular insult CVI vertebrobasilar disorder VBI ICD9 ICD 10 M430 M435 stroke complications risk Kiropraktor sjukgymnast fysioterapeut naprapat manipulation stroke SMT OMT VAD CAD CeAD cerebrovaskulär insult CVI VBI ICD9 ICD 10 M430 M435 stroke risk Physiotherapy Sjukgymnastik
110	The impact of distributed leadership practices on the functioning of primary schools in Johannesburg South Singh, Sharita 10 1900 (has links) In this study, the researcher explored the prevalence of distributed leadership practices in schools in Johannesburg South in order to illustrate how the principals in effective schools collaborated with different members of staff to ensure the school’s success. To this end, a literature study was undertaken on relevant theories and on the results of previous research on the issue. The study explored literature from local and international perspectives on distributed leadership to understand how this form of leadership impacted the functioning of primary schools in Johannesburg South. This was followed by an empirical investigation using judgemental and purposive sampling methods to select participants. A mixed methods research design was employed to elicit both quantitative and qualitative data from a single, structured questionnaire. Participants included 86 respondents from 9 primary schools. Throughout the research study, ethical considerations like keeping confidentiality of information provided and anonymity of research participants were upheld. Data analysis involved a mix of quantitative data analysis and content analysis. Based on the findings, recommendations were made to the GDE and school principals on support needed by teachers if distributed leadership is to ensure school effectiveness. The study found that distributed leadership not only motivated teachers, but compelled them to recognise their own strengths and weaknesses, and contribute to school leadership by taking on roles that interest them. Schools in Johannesburg South have created a culture in which distributed leadership tends to flourish. Distributed leadership ensures that a myriad of well-developed teachers exist at all ranks of the school, who have the capacity to fill vacant positions when a need arises to ensure the smooth functioning of schools. / Educational Management and Leadership / M. Ed. (Education Management) Capacity building Extra mural programme Learners Mentoring Primary school School effectiveness School improvement School management team (SMT) Quintile 372.120110968221

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