• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 4
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 20
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
11

Étude du taux de production des J/psi et muons simples en collisions proton-proton à l'aide du spectromètre à muons de l'expérience ALICE au LHC

Lenhardt, Matthieu 08 December 2011 (has links) (PDF)
Le plasma de quarks et de gluons est un état de la matière apparaissant à haute température. En laboratoire, il est possible d'atteindre les conditions nécessaires à sa formation grâce aux collisions d'ions lourds aux énergies ultra-relativistes. L'expérience ALICE au LHC est dédiée à l'étude du plasma de quarks et de gluons grâce aux collisions Pb-Pb à 2,76 TeV. Les premiers résultats d'ALICE, presentés en annexe, ont été obtenus grâce aux rayons cosmiques. Une étude de l'évolution de l'efficacité de reconstruction du spectromètre à muons durant ses deux premières années de fonctionnement sera présentée par la suite. L'efficacité totale de reconstruction des chambres de trajectographie ainsi obtenue est de plus de 90% pour les données correspondant à des collisions proton-proton, et de 85% pour les données recueillies avec des collisions plomb-plomb. Une méthode de sélection des traces reposant sur la distribution du produit impulsion - distance d'approche minimale sera également présentée. Cette sélection permet de rejeter les traces de muons produits par des collisions entre les particules du faisceau et le gaz résiduel dans le tube faisceau, et les fausses traces dans les collisions Pb-Pb les plus centrales. Enfin, cette thèse présentera une première analyse sur le taux de production des muons simples et des J/psi en fonction de la multiplicité en particules chargées lors des collisions proton-proton.
12

Analytical Comparison of Multimicrophone Probes in Measuring Acoustic Intensity

Wiederhold, Curtis P. 10 August 2011 (has links)
In the late 1970s, a method was developed to estimate acoustic intensity in one dimension by taking the cross-spectral density of two closely-spaced microphone signals. Since then, multimicrophone probes have been developed to measure three-dimensional intensity as well as energy density. Their usefulness has led to the design of various types of multimicrophone probes, the most common being the four-microphone orthogonal, the four-microphone regular tetrahedron, and the six-microphone designs. These designs generally either consist of microphones suspended in space near each other or mounted on the surface of a sphere. This work analytically compares the relative merits of each probe design in measuring acoustic intensity and investigates the various finite-sum and finite-difference processing methods used with each. The analysis is limited to probes consisting of perfect point sensors in plane wave fields. The comparison is given in terms of average and maximum errors for intensity magnitude and direction as a function of angle of incidence as well as the spread between maximum and minimum errors for intensity magnitude. After existent probe geometries are reviewed, optimization techniques are introduced to predict what the optimal probe geometry would be for any given scenario. The probe is optimized to give the lowest intensity error averaged over angle of incidence of plane waves. This is done for full-space and half-space scenarios.
13

Search for Quark-Gluon Plasma Effects in 510 GeV RHIC Proton+Proton Collisions

Riehl, Michael 15 May 2023 (has links)
No description available.
14

Inference for Birnbaum-Saunders, Laplace and Some Related Distributions under Censored Data

Zhu, Xiaojun 06 May 2015 (has links)
The Birnbaum-Saunders (BS) distribution is a positively skewed distribution and is a popular model for analyzing lifetime data. In this thesis, we first develop an improved method of estimation for the BS distribution and the corresponding inference. Compared to the maximum likelihood estimators (MLEs) and the modified moment estimators (MMEs), the proposed method results in estimators with smaller bias, but having the same mean squared errors (MSEs) as these two estimators. Next, the existence and uniqueness of the MLEs of the parameters of BS distribution are discussed based on Type-I, Type-II and hybrid censored samples. In the case of five-parameter bivariate Birnbaum-Saunders (BVBS) distribution, we use the distributional relationship between the bivariate normal and BVBS distributions to propose a simple and efficient method of estimation based on Type-II censored samples. Regression analysis is commonly used in the analysis of life-test data when some covariates are involved. For this reason, we consider the regression problem based on BS and BVBS distributions and develop the associated inferential methods. One may generalize the BS distribution by using Laplace kernel in place of the normal kernel, referred to as the Laplace BS (LBS) distribution, and it is one of the generalized Birnbaum-Saunders (GBS) distributions. Since the LBS distribution has a close relationship with the Laplace distribution, it becomes necessary to first carry out a detailed study of inference for the Laplace distribution before studying the LBS distribution. Several inferential results have been developed in the literature for the Laplace distribution based on complete samples. However, research on Type-II censored samples is somewhat scarce and in fact there is no work on Type-I censoring. For this reason, we first start with MLEs of the location and scale parameters of Laplace distribution based on Type-II and Type-I censored samples. In the case of Type-II censoring, we derive the exact joint and marginal moment generating functions (MGF) of the MLEs. Then, using these expressions, we derive the exact conditional marginal and joint density functions of the MLEs and utilize them to develop exact confidence intervals (CIs) for some life parameters of interest. In the case of Type-I censoring, we first derive explicit expressions for the MLEs of the parameters, and then derive the exact conditional joint and marginal MGFs and use them to derive the exact conditional marginal and joint density functions of the MLEs. These densities are used in turn to develop marginal and joint CIs for some quantities of interest. Finally, we consider the LBS distribution and formally show the different kinds of shapes of the probability density function (PDF) and the hazard function. We then derive the MLEs of the parameters and prove that they always exist and are unique. Next, we propose the MMEs, which can be used as initial values in the numerical computation of the MLEs. We also discuss the interval estimation of parameters. / Thesis / Doctor of Science (PhD)
15

«Игровой мир» как проявление творческой стратегии в сказах П. П. Бажова : магистерская диссертация / The Space of Game as a Manifestation of Creative Strategy in Bazhov's Narrations

Уймина, А. Г., Uymina, A. G. January 2016 (has links)
The thesis reveals features of the creative manner of Bazhov embodied in style of narrations. The author describes Bazhov's appeal to the game strategy and its manifestation in the representation of space and time, in the images of narrations, in the movement of a plot and the use of game receptions in literature poetics. Game types in early and in late works of the writer are compared. Value of the game moment reveals during creation of an image of the author. / Диссертация раскрывает особенности творческой манеры Бажова, воплощенной в стиле сказов. Автор описывает обращение Бажова к игровой стратегии и ее проявление в организации пространства и времени, образах сказов, развитии сюжета и приемов игры. Сопоставляются игровые типы в раннем и в позднем творчестве писателя. Раскрывается значение игрового момента при создании образа автора.
16

Disseleneto de p-metoxi fenila atenua o prejuízo cognitivo e a injúria cerebral em um modelo da doença de alzheimer em roedores / P,p -methoxyl-diphenyl diselenide attenuates the cognitive impairment and the brain injury in a sporadic dementia of alzheimer's type in rodents

Pinton, Simone 17 September 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Alzheimer s disease (AD) is a progressive neurodegenerative disorder, mainly characterized by memory and intellectual capacity loss. AD is characterized by deposition of amyloid-β peptide, neurofibrillary tangles, neuroinflammation, energy metabolism impairment, oxidative stress and synaptic dysfunction and loss. Its multiple pathological pathways contribute to the difficulty of AD treatment and prevention. Thus, the development of new therapies for AD curing or treatment is a challenge. The purpose of this study was to indicate an organoselenium moiety, p,p -dimethoxyl-diphenyl diselenide [(MeOPhSe)2], as a promising alternative for the treatment and prevention of sporadic dementia of Alzheimer-type (SDAT), using an experimental model of dementia induced by intracerebroventricular (i.c.v.) injection of streptozotocin (STZ) in rodents. Initially, it was investigated the prophylactic action of (MeOPhSe)2. For this, mice were treated with (MeOPhSe)2 (25 mg/kg, by gavage) and STZ (2μl of 2,5mg/ml solution; i.c.v.) or vehicles, and 48h after that, the treatment was repeated. The tasks of step-down-type passive-avoidance (SDPA), Y-maze and Morris water-maze (MWM), that followed this treatment, showed that (MeOPhSe)2 protected against the impairment in learning and memory caused by i.c.v. injection of STZ in mice. (MeOPhSe)2 protected against the increase in reactive species (RS) and the reduction of glutathione (GSH) levels, as well as modulated the antioxidant enzymes. (MeOPhSe)2 inhibited the acetylcholinesterase (AChE) activity, which was increased by STZ. Subsequently, it was investigated the effectiveness of (MeOPhSe)2 in reversing the cognitive impairment and neuronal damage induced by STZ. Therefore, rats were injected with STZ (1.0 mg/8μl; 4μl/ventricle) twice, 48h apart. After 21 days of STZ injection, regular diet fed rats were supplemented with 10ppm of (MeOPhSe)2 during 30 days. At the end of this period, it was observed that (MeOPhSe)2 dietary supplementation reversed STZ-induced memory impairment in MWM, SDPA and object recognition tasks. The results on SDPA and object recognition tasks demonstrated that the (MeOPhSe)2 improved memory in rats per se. STZ enhanced the RS and protein nitration levels in cortex and decreased GSH levels on hippocampus of rats, (MeOPhSe)2 reversed these alterations. (MeOPhSe)2 normalized AChE activity (which was enhanced by STZ) in both cortex and hippocampus, but did not reverse the deficit in cerebral glucose metabolism (ATP turnover was decrease by STZ). (MeOPhSe)2 was effective in reducing STZ-induced neuronal (apoptosis) loss. Moreover, (MeOPhSe)2 suppressed neuroinflammation induced by STZ in the rats hippocampus. The organoselenium inhibited activation of microglia and astrogliosis. Based on these results, it was concluded that: 1) (MeOPhSe)2 protected and reversed the cognitive abilities decline; 2) the mechanisms involved in the neuroprotective effect of (MeOPhSe)2 are: antioxidant, AChE inhibitor; inflammation suppressor; 3) (MeOPhSe)2 did not alter the energy metabolism; and 4) (MeOPhSe)2 reduced the neuronal death. Therefore, the present study demonstrated that (MeOPhSe)2 is a promising alternative for the drug studies for treatment of cognitive disorders such as SDAT. / A doença de Alzheimer (DA) é uma síndrome neurodegenerativa progressiva caracterizada principalmente por uma perda da memória e da capacidade intelectual. Ela é caracterizada pelo depósito de fragmentos β-amilóides; emaranhados neurofibrilares; neuroinflamação; déficit do metabolismo energético; estresse oxidativo e deficiência da neurotransmissão. As múltiplas vias patológicas da DA dificultam sua prevenção e tratamento. Logo, o desenvolvimento de novas terapias para a DA é um desafio. Por esta razão, este trabalho procurou apontar uma nova molécula orgânica contendo selênio, o disseleneto de p-metoxi fenila [(MeOPhSe)2], como uma alternativa promissora para o tratamento e prevenção da demência decorrente da DA (DEDA), usando um modelo experimental de demência induzida pela injeção intracerebroventricular (i.c.v.) de estreptozotocina (ETZ) em roedores. Inicialmente, avaliou-se o efeito profilático do (MeOPhSe)2. Para tal, camundongos receberam uma dose oral do organoselênio (25mg/kg, gavage) 30 minutos antes da ETZ (2μl de uma solução 2,5mg/ml), esse procedimento foi repetido 48horas depois. Os testes da esquiva passiva, do labirinto em Y e aquático de Morris, que sucederam esse tratamento, revelaram que o (MeOPhSe)2 protegeu os camundongos do prejuízo cognitivo induzido pela ETZ. O (MeOPhSe)2 protegeu o tecido cerebral do aumento das espécies reativas (ER) e da diminuição dos níveis de glutationa (GSH) induzidos pela ETZ, assim como modulou a atividade de enzimas antioxidantes. O (MeOPhSe)2 inibiu a atividade da acetilcolinesterase (AChE), a qual foi estimulada pela ETZ. Posteriormente, investigou-se a efetividade do (MeOPhSe)2 em reverter o prejuízo cognitivo e os danos neuronais induzidos pela ETZ. Para isso, a ETZ foi injetada nos ratos (1μg/8μl, 4μl/ventrículo) em 0 e 48horas. Passados 21dias, iniciou-se uma suplementação dietética com 10ppm de (MeOPhSe)2 durante 30dias. Ao final deste período, observou-se que o (MeOPhSe)2 restaurou as habilidades cognitivas prejudicadas pela ETZ nos ratos, nos testes do labirinto aquático de Morris, esquiva passiva e reconhecimento do objeto. Os resultados referentes aos testes do reconhecimento do objeto e da esquiva passiva apontaram que o (MeOPhSe)2 melhorou per se a memória dos ratos. A ETZ aumentou os níveis de ER e de nitração de proteínas no córtex e diminuiu os níveis de GSH no hipocampo dos ratos, o (MeOPhSe)2 reverteu estas alterações. O organoselênio inibiu a atividade da AChE (aumentada pela ETZ) tanto no córtex como no hipocampo dos ratos, mas não modulou o metabolismo da glicose (ETZ diminuiu ATP-turnover). O (MeOPhSe)2 evitou a perda neuronal (apoptose) e inibiu os eventos neurodegenerativos (ativação da caspase-3) induzidos pela ETZ. O (MeOPhSe)2 suprimiu a neuroinflamação induzida pela ETZ no hipocampo dos ratos. O organoselênio inibiu a ativação das células gliais e astrócitárias. Baseado nestes resultados, conclui-se que: 1) O (MeOPhSe)2 protegeu e reverteu o declínio das habilidades cognitivas; 2) Os mecanismos envolvidos no efeito neuroprotetor do (MeOPhSe)2 são: antioxidante; inibidor da AChE; supressor da neuroinflamação; 3) O (MeOPhSe)2 não altera o metabolismo energético; e 4) O (MeOPhSe)2 reduziu a morte neuronal. Assim sendo, este trabalho demonstrou que o (MeOPhSe)2 é uma alternativa promissora para o estudo de drogas para o tratamento de desordens cognitivas como a DEDA.
17

Vizualizace biomedicinských dat v prostředí Matlab / Biomedical data visualization using Matlab

Zvončák, Vojtěch January 2016 (has links)
The thesis deals with the visualization of biomedical data in MATLAB environment. The thesis contains following statistical methods and their descriptions: P-P plot, Q-Q plot, histogram, box plot, kernel denstity estimation, scatter plot and several time series metrics. Some functions are programmed from buil-in functions of MATLAB and others using external functions, which are changed to fit to this thesis’s purpose. First part of the thesis conserns theoretical background, whereas the second part conserns practical programmed realizations of mentioned functions. The program contains a graphical user interface - GUI, which the thesis describes in detail. The purpose of the GUI is to ensure ease of use and also data processing. The output graphs of GUI are shown in chapter 5. The last part deals with the possible extensions of the program.
18

Charged particle distributions and robustness of the neural network pixel clustering in ATLAS

Sidebo, Edvin January 2016 (has links)
This thesis contains a study of the robustness of the artificial neural network used in the ATLAS track reconstruction algorithm as a tool to recover tracks in dense environments. Different variations, motivated by potential discrepancies between data and simulation, are performed to the neural network’s input while monitoring the corresponding change in the output. Within reasonable variation magnitudes, the neural networks prove to be robust to most variations. In addition, a measurement of charged particle distributions is summarised. This is one of the first such measurements carried out for proton-proton colli- sions at √s = 13 TeV, limited to a phase space defined by transverse momentum pT &gt; 100 MeV and absolute pseudorapidity |η| &lt; 2.5. Tracks are corrected for de- tector inefficiencies and unfolded to particle-level. The result is compared to the prediction of different models. Overall, the EPOS and Pythia 8 A2 models show the best agreement with the data. / Spår från elektriskt laddade partiklar rekonstrueras i ATLAS genom att kombinera mätningar från de innersta subdetektorerna. I de extrema miljöer som skapas i proton-proton-kollisionerna i Large Hadron Collider vid CERN är det av yttersta vikt att algoritmen för att rekonstruera spår är högpresterande. Uppgiften är särskilt svår i partikelrika miljöer där flera partiklar färdas nära varandra, åtskilda av avstånd jämförbara med storleken på detektorns utläsningselement. Ett artificiellt neuralt nätverk används i algoritmen för att klassificera mätdata från pixeldetektorn, belägen närmast interaktionspunkten, för att lyckas identifiera spår i partikelrika miljöer som annars hade gått förlorade. I denna avhandling utreds det neurala nätverkets stabilitet. Dess känslighet studeras genom att manuellt manipulera dess indata och därefter utvärdera dess resultat. Nätverket tränas med simulerad data. Variationerna i indata är utformade för att undersöka skillnader mellan data och simulering, orsakade av osäkerheter i simuleringsmodellen eller osäkerheter i pixeldetektorns kalibrering. Av de undersökta variationerna har en osäkerhet i skalan eller utläsningströskeln för pixeldetektorns kalibrering den största effekten på nätverkets resultat. Andra variationer har en betydligt mindre påverkan. Avhandlingen presenterar också en studie av distributioner av elektriskt laddade partiklar producerade i proton-proton-kollisioner. Det är en av de första studierna av partikeldistributioner för Large Hadron Colliders andra körning med mass-centrum-energi √s = 13 TeV. Mätningen är begränsad till fasrymden definierad av en transversell rörelsemängd pT &gt; 100 MeV, och absolut rapiditet |η| &lt; 2.5. Spår av partiklar rekonstrueras och korrigeras för detektorns ineffektiviteter för att presenteras på partikelnivå. Dessa jämförs sedan med förutsägelser från olika modeller. Modellerna EPOS och Pythia 8 A2 är generellt de som bäst överensstämmer med data. Författaren har undersökt partiklar som migrerar in och ut ur fasrymden. Andelen spår associerade till partiklar som migrerat utifrån uppskattas med simulerad data, till som mest 10% nära fasrymdens gränser. Osäkerheten på denna andel uppskattas till att vara som mest 4.5%, huvudsakligen orsakad av osäkerheten på mängden material i de innersta subdetektorerna. / <p>QC 20160817</p>
19

Topologically Designed Cylindrical and Spherical Building Blocks to Construct Modular-Assembled Structures in Giant Shape-Amphiphiles

JIANG, JING 24 May 2018 (has links)
No description available.
20

L'appropriation des outils de gestion et performance hospitalière : pour une approche interculturelle / Management tool appropriation and hospital performance : towards an intercultural approach

Gouffé, Valérie 04 June 2013 (has links)
Avec les récentes réformes, dont la loi Hôpital, Patient, Santé et Territoires (HPST) de Juin 2009, l’hôpital s’est transformé non seulement dans sa forme organisationnelle par la mise en oeuvre des pôles mais aussi dans son rapport à son environnement. Cette organisation polaire vise à rechercher une performance par une approche médico-économique. Ainsi les dispositifs de gestion ont été mis en place et cherchent à rendre compte de cette performance. Dans ce contexte, comment peuvent travailler des professionnels de champs aussi différents que celui de la gestion et celui du soin ? La gestion sous-entend une optimisation des moyens, alors que le service public défend en priorité des valeurs d’utilité sociale et d’attention aux usagers. Les acteurs du soin ont une forte identification professionnelle à cette mission d’utilité sociale. Dans ce travail, nous proposons d’identifier en quoi les décalages culturels au sein des pôles hospitaliers, participent à une perte de sens et de reconnaissance des agents à leur travail. Ces écarts culturels seront appréciés plus précisément au travers de l’appropriation des outils de gestion. Cette étude se base sur des entretiens réalisés au sein de différents hôpitaux (CHU et CH) et de secteur Médecine, Chirurgie, Obstétrique (MCO) et psychiatrie. Elle révèle lanécessité de pratiques managériales innovantes tournées notamment vers la gestion interculturelle afin que chaque acteur de ces nouvelles structures hospitalières se sente compris et intégré dans cette dynamique. L’étude proposée peut constituer un retour d’expérience intéressant pour mieux comprendre et améliorer l’utilisation des nouveaux outils de gestion. Des préconisations sont proposées et peuvent constituer des pistes de réflexion afin de répondre aux défis actuels de l’hôpital public. / With the latest reforms, among which the Hospital, Patient, Healthcare and Territory (HPST) Law, the French Hospital has changed not only the form of its organisation through the implementation of a polar organisation, but also its environmental concern. This polar organisation aims to strive for performance and efficiency via an managerial and medical approach. Thus, some management tools have been set up aimed in particular at giving feedback on such performance. In this context, how can professionals from such distinct fields as management and healthcare work? Management implies the optimization of resources when the public sector above all upholds values of social usefulness and patient care. Healthcare actors feel very much involved in this mission of social usefulness. In this work we propose to identify how cultural gaps within hospital poles contribute to a loss of meaning and acknowledgment among healthcare agents. Those cultural gaps will be examined more particularly through management tool appropriation. This study relies on interviews conducted in various healthcare facilities (PCO and psychiatric hospitals of various capacities such as CHU and CH). It reveals the need for innovative managerial practices, especially designed for intercultural management, so that every actor of these new hospital facilities may feel that they are understood and integrated in this dynamic process. The proposed study can make up interesting feedback to better understand and improve the use of these new management tools. Recommendations are issued that can be food for thought to meet the current challenges of public hospitals.

Page generated in 0.0433 seconds