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1
Schmidt, Daniel. "Kinetic Monte Carlo Methods for Computing First Capture Time Distributions in Models of Diffusive Absorption." Scholarship @ Claremont, 2017. https://scholarship.claremont.edu/hmc_theses/97.
Abstract:
In this paper, we consider the capture dynamics of a particle undergoing a random walk above a sheet of absorbing traps. In particular, we seek to characterize the distribution in time from when the particle is released to when it is absorbed. This problem is motivated by the study of lymphocytes in the human blood stream; for a particle near the surface of a lymphocyte, how long will it take for the particle to be captured? We model this problem as a diffusive process with a mixture of reflecting and absorbing boundary conditions. The model is analyzed from two approaches. The first is a numerical simulation using a Kinetic Monte Carlo (KMC) method that exploits exact solutions to accelerate a particle-based simulation of the capture time. A notable advantage of KMC is that run time is independent of how far from the traps one begins. We compare our results to the second approach, which is asymptotic approximations of the FPT distribution for particles that start far from the traps. Our goal is to validate the efficacy of homogenizing the surface boundary conditions, replacing the reflecting (Neumann) and absorbing (Dirichlet) boundary conditions with a mixed (Robin) boundary condition.
2
Karagulyan, Avetik. "Sampling with the Langevin Monte-Carlo." Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAG002.
Abstract:
L’échantillonnage des lois aléatoires est un problème de taille en statistique et en machine learning. Les approches générales sur ce sujet sont souvent divisées en deux catégories: fréquentiste vs bayésienne. L’approche fréquentiste corresponds à la minimisation du risque empirique, c’est à dire à l’estimation du maximum vraisemblance qui est un problème d’optimisation, tandis que l’approche bayésienne revient à intégrer la loi postérieure. Cette dernière approche nécessite souvent des méthodes approximatives car l’intégrale n’est généralement pas tractable. Dans ce manuscrit, nous allons étudier la méthode de Langevin, basée sur la discrétisation de l’EDS de Langevin. La première partie de l’introduction pose le cadre mathématique et l’intérêt d’étudier plus avant la question de l'échantillonnage. La suite de l’introduction s’attache à la présentation des méthodes d’échantillonnage.Le premier article concerne les bornes non-asymptotiques sur la convergence en distance de Wasserstein de Langevin Monte-Carlo pour les fonctions de potentiel lisses et fortement convexes. Nous établissons d’abord des bornes explicites pour LMC avec des step-sizes variantes?. Puis nous étudions la convergence pour des fonctions de potentiel avec des gradients stochastiques. Enfin, deux types de discrétisation sont présentés, pour les potentiels plus réguliers.Dans la deuxième article nous abordons le problème d’échantillonnage de loi log-concave (pas fortement) en utilisant LMC, KLMC et KLMC2. Nous proposons une pénalisation quadratique constante de la fonction de potentiel. Puis nous prouvons des bornes non-asymptotiques sur l’erreur de Wasserstein de ces méthodes pour le choix de pénalisation optimale. Enfin, nous soulignons l’importance du choix de l’échelle pour le mesurage des complexités des différentes méthodes.La troisième contribution principales est concentrée sur la convergence de la diffusion de Langevin dans le case log-concave. Une pénalisation variable dans le temps est proposée pour la fonction de potentiel. Nous prouvons des bornes explicites pour cette méthode nommée Penalized Langevin Dynamics. A la fin, le lien entre les algorithmes de Langevin et l’optimisation convexe est établi, ce qui nous permet de prouver des bornes similaires pour le gradient flowSampling from probability distributions is a problem of significant importance in Statistics and Machine Learning. The approaches for the latter can be roughly classified into two main categories, that is the frequentist and the Bayesian. The first is the MLE or ERM which boils down to optimization, while the other requires the integration of the posterior distribution. Approximate sampling methods are hence applied to estimate the integral. In this manuscript, we focus mainly on Langevin sampling which is based on discretizations of Langevin SDEs. The first half of the introductory part presents the general mathematical framework of statistics and optimization, while the rest aims at the historical background and mathematical development of sampling algorithms.The first main contribution provides non-asymptotic bounds on convergence LMC in Wasserstein error. We first prove the bounds for LMC with the time-varying step. Then we establish bounds in the case when the gradient is available with a noise. In the end, we study the convergence of two versions of discretization, when the Hessian of the potential is regular.In the second main contribution, we study the sampling from log-concave (non-strongly) distributions using LMC, KLMC, and KLMC with higher-order discretization. We propose a constant square penalty for the potential function. We then prove non-asymptotic bounds in Wasserstein distances and provide the optimal choice of the penalization parameter. In the end, we highlight the importance of scaling the error for different error measures.The third main contribution focuses on the convergence properties of convex Langevin diffusions. We propose to penalize the drift with a linear term that vanishes over time. Explicit bounds on the convergence error in Wasserstein distance are proposed for the PenalizedLangevin Dynamics and Penalized Kinetic Langevin Dynamics. Also, similar bounds are proved for the Gradient Flow of convex functions
3
Mauland, Eirik. "Utherdbare bimetall materialer fremstilt ved skrueekstrudering: AA 6060/ren magnesium." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21845.
Abstract:
Skruekstrudering er en ny, innovativ prosess for å fremstille metaller. Prosessens store fortrinn er et relativt lav energiforbruk sammenliknet med tradisjonell ekstrudering, noe som i dagens energisamfunn er meget aktuelt. Prosessen går ut på å mate granuler/pulver i en skrue som transporterer og konsoliderer metallet mot en dyseåpning. Friksjon og deformasjonsenergi varmer opp godset sammen med påført induksjonsvarme i ekstruderingsdysen slik at det oppnås plastisk flyt i ekstruderingskammeret og godset presses gjennom dyseåpningen til en ferdig profil. I dette forsøket ble det undersøkt hvordan tilsats av ren magnesium granuler (rest AA6060 granuler) påvirket mikrostruktur og mekaniske egenskaper. Målet med ekstruderingen var å danne en Al/Mg metallmatriks kompositt (MMC). Fire komposisjoner ble skruekstrudert i forsøket: AA6060 + 5 wt % Mg AA6060 + 7,5 wt % Mg AA6060 + 10 wt % Mg AA6060 + 12,5 wt % Mg Ekstrudat av 5 wt % Mg og 7,5 wt % Mg gjennomgikk to herdeoppsett, utherding (T5) og inn- og utherding (T6). Mikrostuktur og mekaniske egenskaper ble undersøkt for ekstrudatene i herdetilstandene uherdet (F), utherdet (T5) og inn- og utherdet (T6). Det ble dannet et Al/Al3Mg2(Al12Mg17) AMMC etter skruekstrudering av hhv 5, 7,5, 10 og 12,5 wt % Mg. Matriksen bestod av Al(Mg), med spiralbånd og fint fordelt Al3Mg2(Al12Mg17). Det var store periodiske variasjoner i ekstruderingshastighet av 10 og 12,5 wt % Mg grunnet manglende flyt i materialet og minkende moment fra skruen grunnet minkende klebningsfriksjon ved økt Mg tilsats. 5 og 7,5 wt % Mg viste jevn ekstruderingshastighet. Fasefordelingen endret seg som funksjon av økt mg tilsats. 5 wt % Mg viste kun tydelige intermetalliske spiralbånd, mens 7,5, 10 og 12,5 wt % Mg i økende grad viste fint fordelte intermetalliske faser i matriksen i tillegg til de intermetalliske spiralbåndene. Den intermetalliske fasefordelingen over tverrsnittet var konsentrert i en sone mellom senter og ytterkant for alle ekstrudater. Sidekant og senter viste lite intermetalliske faser. Ekstrudatene viste økende flytespenning, strekkfasthet og hardhet som funksjon av økt Mg tilsats for ekstrudatene med hhv 5, 7,5 og 10 wt % Mg tilsats. Dette var et resultat av økt arbeidsherding og fast løsningsherding grunnet høyere mengder Mg i matriksen og økt dispersjonsherding fra de intermetalliske fasene som økte i omfang og fordeling i matriksen. Forlengelsen avtok som funksjon av økt Mg tilsats. De mekaniske egenskapene varierte betraktelig mellom parallellene i hvert ekstrudat og vitnet om inhomogene ekstrudatlengder. Majoriteten av Al(Mg) matriksen til alle ekstrudater viste en fin likeakset dynamisk rekrystallisert kornstruktur på <15 m. Kornstrukturen omkring intermetalliske faser inneholdt deformert kornstruktur av feedstock strukturen i tillegg til dynamisk rekrystallisert struktur. T5 herding ga herdebidrag til flytespenningen for 5 wt % Mg på ca 70 % og ca 10-20 % for 7,5 wt % Mg. T6 herding ga herdebidrag til flytespenningen for 5 wt % Mg på ca 40-70 % og ca 10-20 % for 7,5 wt % Mg. Mikrostrukturen til T6 herdede prøver viste omfattende rekrystallisering og kornvekst i områdene ut mot sidekantene, foruten dette var kornstrukturen tilnærmet uavhengig av herdingen. Strekkprøvene av 5 wt % Mg viste duktil bruddprofil, strekkprøvene av 7,5 wt % Mg viste kombinert sprø og duktil bruddprofil og strekkprøvene av hhv 10 og 12,5 wt % Mg viste sprø bruddprofil. Bruddprofilen til 7,5, 10 og 12,5 wt % Mg viste delaminering i spiralbånd med intermetalliske faser over tverrsnittet. Et konservativt overslag viste at overgangen mellom duktil til sprø bruddprofil inntraff ved hardheter mellom 70-80 og 90-100 HV(1) i matriks.
4
Moazzam, Muhammad. "The role of the WASP family proteins in cellular migration and invasion in prostate cancer." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/60160/.
Abstract:
Prostate cancer metastasis is a complex process, involving multiple pathways in its orchestration. Malignant cells are influenced by different growth factors from the extracellular environment which promote or inhibit cell movement and metastasis. HGF has been implicated in progression and metastasis of prostate cancer. A cell interacts with the environment through surface molecules like integrins. These interactions are further translated in to different responses through various intracellular machineries. Furthermore organization of the actin cytoskeleton is vital for many cellular functions. WAVEs are member of WASP family of proteins, which have important role in regulation of actin dynamics through regulation of actin related protein (ARP 2/3). The role of individual members of WASP family has been investigated in development and progression of different cancers. We documented the expression of different WAVE family members in various prostate cancer cell lines. Expression of WAVE-3 was effectively knocked down with the use of hammer head ribozymes. Loss of WAVE-3 expression resulted in reduced cell movement and invasion in the PC-3 cell line. These cells failed to show any significant increase in cellular movement and invasive potential following treatment with HGF. Further experiments to investigate the underlying mechanism of this phenotypic change revealed that optimum levels of phosphorylated paxillin play an important role in this change. Our study also indicates that reduced potential of invasive capability following WAVE-3 knock down, may be related to reduced availability of MMP-2 in the cellular environment.
5
Graf, P. O. "Combining oxidative coupling and reforming of methane vision or utopia? /." Enschede : University of Twente [Host], 2009. http://doc.utwente.nl/60460.
6
Morgado, Norbert. "Tréfilage à chaud de l'aluminium 6060 : nouvelle méthodologie d'identification du comportement tribologique." Valenciennes, 2003. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/38039928-2561-413f-987a-d3f0fe90893f.
Abstract:
L'étude proposée s'appuie sur le procédé instrumenté de tréfilage à chaud de l'aluminium. Ce procédé est analysé d'un point de vue thermomécanique afin de dégager l'importance des paramètres d'interface dans la maîtrise du procédé. Les paramètres prépondérants sont le coefficient de frottement et le coefficient de transfert thermique entre le fil et la filière. La mise en place d'un nouveau banc d'essai permet d'identifier ces paramètres. Le banc, équipé d'un système de chauffage par induction et d'un système hydraulique asservi, permet de reproduire au plus près les conditions de contact thermomécaniques rencontrées en mise en forme à chaud. Une méthodologie multi niveaux, s'appuyant sur l'exploitation des résultats issus du banc, est présentée. Celle-ci permet de répondre à diverses attentes en terme d'optimisation de procédé, de caractérisation de conditions de frottement, d'analyse de défauts de surface (collage) ou de détermination de lois tribologiquesThe proposed study is based on the specific hot wire drawing process of aluminium. This process is thermomechanically analysed in order to point out the importance of interface parameters in the process control. The main parameters are the friction coefficient and the heat transfer coefficient. A new test device is developed to evaluate them. This test is made of a heating induction system and a servo-hydraulic system. It allows to reproduce accurately the thermomechanical contact conditions observed in hot metal forming. A multi level methodology, using exploitation of test device results, is presented. It allows to optimize the process, to identify friction conditions, to analyse surface damages (sticking) or to estimate tribological laws
7
Monteiro, Paulo Cyhlar. "Efeito do perfil de envelhecimento artificial nas ligas AI 6060 e 6061." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17771.
Abstract:
Mestrado em Engenharia de MateriaisEste trabalho teve como objetivo estudar a influência do perfil térmico de envelhecimento artificial nas propriedades mecânicas das ligas Al 6060 e 6061. Para tal foram cedidos pela Extrusal, provetes, biletes e fatias das ligas em questão. Da liga 6061 os lotes de material vieram na condição de homogeneizados (direto do fornecedor); extrudidos na empresa com envelhecimento térmico natural (T4) e armazenamento em fábrica e dispositivo de frio; também extrudidos na empresa com envelhecimento artificial (T6), igualmente conservados em ambiente de fábrica e congelados; da liga 6060 foi fornecida uma fatia na condição de homogeneizada. Para verificar qual a influência do perfil térmico de envelhecimento artificial nas propriedades mecânicas das ligas Al 6060 e 6061, amostras retiradas das fatias homogeneizadas foram submetidas a um tratamento térmico de envelhecimento, com velocidade de aquecimento de 1 ºC/min ou de 10 ºC/min, com um patamar isotérmico de envelhecimento a 180 ºC, seguido de arrefecimento ao ar ou em água. Foram feitos testes de dureza (Vickers) para perceber o efeito na dureza das diversas condições térmicas no processamento da liga. A análise microestrutural e composicional através de SEM, TEM e EDS foi usada para explicar as variações de comportamento. Os resultados obtidos confirmaram a adequação das condições dos biletes à chegada, e da eficácia do tratamento T6. Parece igualmente irrelevante o efeito do envelhecimento natural nos ensaios realizados. Como complemento, foi ainda identificada a importância de eventuais cargas com diferentes massas térmicas, suscetíveis de introduzir diferentes perfis de envelhecimento em condições nominalmente semelhantes.
The main purpose of this study was to study the influence of the thermal profile of artificial aging on the mechanical properties of Al 6060 and 6061 alloys. These alloys were provided by Extrusal as billets and extruded parts. The 6061 alloy samples were obtained in distinct conditions: homogenized billets (from supplier), extruded parts with natural thermal aging (T4) and storage at room temperature or in ice; also extruded parts with artificial aging (T6), again after storage at room temperature or in ice. Alloy 6060 was provided only as a billet slice in homogenized condition. To check the influence of the thermal profile during artificial ageing on mechanical properties of Al 6060 and 6061, samples taken from the homogenized slices were subjected to an aging heat treatment at a heating rate of 1 °C / min or 10 °C / min with isothermal ageing at 180 ° C followed by cooling in air or water. Hardness tests were made (Vickers) to realize the effect on hardness of the various thermal conditions in alloy processing. The microstructural and compositional analysis by SEM, TEM and EDS was used to explain variations in behavior. The results confirmed the appropriateness of the conditions of billets on arrival, and the effectiveness of the T6 treatment. It also seemed irrelevant the effect of natural aging in these tests. As a complement, the importance of different thermal masses in thermal ageing was confirmed, being able to generate different ageing profiles under nominally similar conditions.
8
Nelson, Camilla. "Reading and writing with a tree : practising 'Nature Writing' as enquiry." Thesis, University of the Arts London, 2012. http://ualresearchonline.arts.ac.uk/6060/.
Abstract:
This thesis reframes, or reforms, ‘nature writing’ (‘Nature Writing Reformed’) through the practical and theoretical recombination of human, tree, and page. Understandings of ‘writing’, ‘nature’, and their phrasal relation in ‘nature writing’, are explored through a sustained enquiry into the reading and writing practices principally undertaken by the author (Camilla Nelson) in relation to one specific apple tree in the walled garden of University College Falmouth’s Tremough Campus, Cornwall. The central claim of this thesis is that composition is always environmentally constructive and constructed: how (the method with which) you read and write, and where (the environment in which) you read and write, i.e. the situation and materials you read and write with, affect not only the composition of the written text but the composition of the human, as well as the other-than-human, entities involved in this practice. This thesis is explicitly structured as an interweave of variously material (word; page; room; box; walled garden; library; studio; tree) and conceptual (word; page; theory; footnote; hyperlink; field of research) framing devices (and / or environments). The structure of this thesis and that of the orchard and studio installations, which together constitute the final PhD research submission, play on the variety of framing and reframing that occurs in relation to the spatio-temporal specifics of material and conceptual composition (as evidenced in the Media Log). This ‘reform’ of nature writing, as an interweave of human and other-than-human environments (or frames), is developed in relation to Mark Johnson’s expanded theory of ‘mind’ by way of the conceptual and material practice of metaphor (Johnson, 2007). This thesis combines the theories and practices derived from the (prinicipal) field of ‘Nature Writing’ (as defined in the correspondingly titled chapter), with those suggested by contemporary developments in cognitive philosophy, neuroscience, microbiology, systems theory, and translation studies.
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Braccini, Michele. "Intelligenza artificiale: test di Turing e alcune questioni filosofiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6060/.
10
Martingo, Ângelo Miguel Quaresma Gomes. "Music as postmodern thought : a critical examination of George Crumb's Makrokosmos I." Thesis, University of Sheffield, 2004. http://etheses.whiterose.ac.uk/6060/.
Abstract:
This thesis discusses the piano works of George Crumb, particularly Makrokosmos I, in the light of the Adornian critique of the post-war avant-garde and of Lyotard's theorisation of the postmodem. According to Adomo and Lyotard, modem thought is characterised by a totalising nature and both the Adomian critique of the post-war avant-garde and Lyotard's theorising of the postmodern are directed toward the critique of that character. This thesis shows the way in which Crumb's composition responds to this critique of modernity. Elements of musical structure, text treatment, exploration of timbre, spatiality (music notation and stage setting), and citational practice are identified through an analysis of Makrokosmos L These elements are contextualised both within Crumb's oeuvre (particularly, the piano literature) and within the musical and theoretical production of the post-war avant-garde, and finally, discussed with reference to Lyotard and Adomo's critique of modem thought. It is shown that, in contrast to the self-referentiality of music composition which pervades both integral serialism and experimentalism, Crumb's articulation of musical materials obeys a logic of montage resulting from the blocking of two incommensurable modes of sense, notably, musical structure (analytic unity of the work), and elements which deconstruct that structure (namely timbre, and notation). In addition to the perspective of historical musicology, the investigation discusses specific compositional elements from the point of view of perception (namely timbre) and representation (notably citation, text setting). By doing so, it is intended to show that Crumb deconstructs the totalising rationality pervading modem thought from not only an expressive but also a critical point of view.
11
Valgimigli, Simond <1976>. "Farmacocinetica della buprenorfina, e del suo metabolita norbuprenorfina, somministrata come infusione costante nel periodo post-operatorio in cagne sane sottoposte ad ovariectomia." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/6060/.
Abstract:
Il dolore non è solo una conseguenza della malattia ma un fattore patogeno che è di per se stesso in grado di perpetuare il danno all’organismo. Il suo trattamento non è quindi solo un atto di umanità ma un contributo ad arrestare la malattia e restituire la salute al paziente. Tra i farmaci più popolari per la terapia del dolore negli animali da affezione si trova la buprenorfina. Questa molecola viene impiegata con successo da anni nel cane e nel gatto per motivi riconducibili, oltre che alla sua efficacia (la sua potenza è diverse volte quella della morfina), alla lunga durata d’azione e alla scarsità degli effetti collaterali. Nonostante l’ampia diffusione e longevità del suo utilizzo, però, sappiamo poco della farmacocinetica di questa molecola negli animali da affezione; i dosaggi clinicamente impiegati sono di fatto estrapolati dagli studi nell’uomo oppure basati su semplici osservazioni degli effetti; i pochi dati farmacocinetici ottenuti nel cane fanno riferimento a singoli boli di dosi che non sempre corrispondono a quelle clinicamente impiegate. Nonostante la buprenorfina trovi il suo principale impiego nelle somministrazioni protratte a lungo (durante il periodo post-operatorio o la degenza ospedaliera) non è mai stato indagato il profilo farmacocinetico della molecola somministrata a boli ripetuti o come infusione continua. Il nostro studio si pone come obiettivo di indagare la farmacocinetica della buprenorfina somministrata come bolo di carico seguito da un’infusione costante a dosaggi considerati clinici in cani sani nel periodo post operatorio. Lo scopo ultimo è quello di sviluppare un protocollo per la somministrazione di questa molecola in modo prolungato in pazienti degenti ed addolorati per poi, in futuro, confrontare la somministrazione come infusione continua con i tradizionali boli ripetuti. Per lo studio sono state utilizzate giovani cagne adulte di taglia media o grande sottoposte ad intervento di ovariectomia.Pain isn’t just a consequence of disease but a pathogenetic factor that is itself able to perpetuate the damage to the body. Its treatment isn’t just a matter of humanity but also a contribution to stop the disease and return the patient to health. Among the most popular drugs used for treating pain in pets is buprenorphine. This molecule has been successfully used for years in dogs and cats because, apart from its efficacy (considered to be several times the one of morphine), of its long duration of action and relative lack of side effects. Despite this ample diffusion and longevity in clinical use we don’t know much about pharmacokinetics of this molecule in pet animals; dosage and therapeutic plans are in fact either extrapolated from man or based on clinical observation; the only pharmacokinetic data available in dogs are from single administrations of dosages not always corresponding to clinically used ones. Despite buprenorphine being mainly used for prolonged administrations (in the post-operative period or during hospitalization) it’s never been studied the pharmacokinetic profile of this molecule administered as repeated doses or constant rate infusion. Our study aims at describing the pharmacokinetic of buprenorphine administered as a loading bolus of a dose in the therapeutic range followed by a constant rate infusion. We ultimately intend to develop a protocol for the prolonged administration of this molecule to clinical patients in pain and, eventually, compare the constant rate administration with traditional protocols based on repeating doses. For the purposes of the study young adult female dogs of average to large size were used that were spayed by ovariectomy.
12
Talebian, Kousha. "Automation in anesthesia : a look at L₁ adaptive and PID controllers." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60260.
Abstract:
Control of anesthesia is one of the many tasks performed by anesthesiologists during surgery. It involves adjusting drug dosage by monitoring patient’s vital and clinical signs. A control system can replace this tedious and routine task, and allow the anesthesiologists to concentrate on more life threatening procedures. Because of large intra- and inter-variability in patients Pharmacokinetics and Pharmacodynamics responses, an adaptive controller is desirable. This thesis thoroughly investigates the L₁ Adaptive Control by applying it on 44 simulation cases which cover a wide range of patient demographics. It is found that the controller approaches an implantable non-adaptive LTI controller as the adaptation gain increases, echoing the results found by other researches. This loss of adaptivity is shown through examples and mathematical derivations. It is concluded that the L₁ Adaptive Control in its current form is not applicable to closed-loop control of anesthesia. As an alternative to adaptive controller, partial adaptivity in a PID controller is investigated. iControl, a PID controller designed by us, can sometimes lead to oscillation in the control signal. It is desirable to automatically detect the oscillations and tune the controller in order to remove them. A real-time oscillation detection algorithm is discussed. It detects multiple oscillations in real-time and provides their frequency, amplitude, severity and regularity. A PID auto-tuning algorithm is developed that uses the dominant frequency metrics provided by the oscillation detection algorithm to retune the controller robustly and to guarantee stability. This technique is simulated and tested on 44 cases; the gain and the phase margin in all 44 cases are within < 7% of the optimal tuning parameters of iControl.Applied Science, Faculty of
Graduate
13
Shearing, Giles Andrew. "Sediment transport and bed material adjustments in the vicinity of Wilsey Dam : salmon spawning habitat implications." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60760.
Abstract:
Substrate requirements are an important component of the multifaceted spawning needs of salmon, and this research effort was directed at developing a greater understanding of sediment transport dynamics and bed material response in the Middle Shuswap River in consequence of the emplacement and subsequent management of Wilsey Dam. Downstream of Wilsey Dam the river provides spawning habitat for coho (Oncorhynchus kisutch), chinook (O. tshawytscha), pink (O. gorbuscha) and sockeye (O. nerka) salmon. This thesis suggests that sand dredged from deposits filling the upstream reservoir basin of the dam could be redeposited downstream when coupled with specific flow releases (≥100 cubic metres per second). This is seen as a viable option for sediment management on the Middle Shuswap River aimed at restoring sediment transport processes and preserving spawning habitat. Maintaining sediment transport processes after dam emplacement is an important consideration for ecological processes in rivers, consistent with the notion of holistic dam management (Ligon et al. 1995, Tharme 2003)
An experimental underwater Automated Grain Sizing method was developed for determining the median grain size (D50) of glide facies throughout the 28.4 km study area. On this basis, estimates of viable salmon spawning habitat were updated from 2002 and mapped below (190,906 m2) and above (387,265 m2) Wilsey Dam. Grain size distributions showed a fining trend in the downstream direction for the Middle Shuswap River, with significant coarsening of bed substrate in the 0.2 km section immediately below the canyon downstream of Wilsey Dam. A one-dimensional (1D) sediment transport model, based on the Wilcock and Crowe (2003) transport equation, showed that sand reintroduced during spring freshet to a 1200 m reach below the dam flushed quickly through in the model. Gravel was also mobilized upon sand reintroduction. The model is an oversimplification of site conditions and would need to be field tested during sand reintroduction trials to establish model integrity.
Research undertaken in this thesis contributes to the growing amount of literature on the biophysical impacts of hydroelectric dams and presents ways dam operators can approach and mitigate disruptions to sediment transport process and their resulting ecological impacts.Irving K. Barber School of Arts and Sciences (Okanagan)
Earth and Environmental Sciences, Department of (Okanagan)
Graduate
14
Liu, Chi-Chao. "Alpha-integrin expression and function modify chemoresistance and immunogenicity of acute lymphoblastic leukemia." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60560.
Abstract:
The overall survival rate for pediatric Acute Lymphoblastic Leukemia (ALL) is >85%, achieved mainly via multi-agent chemotherapy. However, therapeutic options remain limited for those experiencing relapse, thus understanding the causes for treatment failures remains an important priority. In this thesis, I investigate the underlying mechanisms that allow leukemic cells to escape chemotherapy. Specifically, I evaluate how integrin-mediated cell adhesion promotes tumor cell survival by increased pro-survival signaling, enhanced resistance to chemotherapeutics, and decreased presentation of immunogenic cell death (ICD) markers. I show that T-lymphoblast adhesion via α4β1-integrin promotes chemoresistance to doxorubicin-induced apoptosis. Expression of α4δ, a tail-truncated α4-integrin with GFFKR as the cytoplasmic motif, promotes chemoresistance in a manner independent of integrin-mediated adhesion. The adhesion-independent chemoresistance is reproduced by expression of Tacδ, a non-integrin transmembrane receptor fused to the cytosolic GFFKR motif. Additionally, the GFFKR motif-mediated chemoresistance is associated with enhanced Akt activation, Ca²⁺ influx, and drug efflux. GFFKR is a conserved motif found in α-integrins and previously shown to interact with calreticulin, a calcium-binding endoplasmic reticulum chaperone protein. I found that α4-calreticulin interaction was enhanced by cell adhesion, while α4δ-calreticulin interaction occurred in an adhesion-independent manner. Since cell surface calreticulin is a pro-phagocytic marker for cells undergoing ICD, the impact of integrin function on surface calreticulin in lymphoblasts treated with ICD-inducing agents was evaluated. Engagement of integrins via adhesion, or expression of the minimal GFFKR motif as α4δ or Tacδ, was sufficient to reduce the levels of surface calreticulin. Furthermore, surface calreticulin was also reduced for cells co-treated with a β1-integrin activating antibody. The resulting integrin-mediated decrease in surface calreticulin significantly reduced engulfment of the target lymphoblasts by macrophages. Calreticulin expression in lymphoblasts was nullified to assess its role in integrin-mediated chemoresistance. Chemosensitivity was partially restored in calreticulin-null Tacδ cells under non-adherent conditions, and in calreticulin-null wildtype cells under adherent conditions. The affect was partly attributed to calreticulin’s role as a regulator of Ca²⁺ influx and drug efflux. Calreticulin was also implicated as a mediator of cytokine-dependent STAT proliferative signaling. This thesis provides evidence for integrin function and cell adhesion as a physiological pro-survival mediator for T-lymphoblasts.Medicine, Faculty of
Experimental Medicine, Division of
Medicine, Department of
Graduate
15
Buntrock, Rebecca (Rebecca Miriam). "Structural performance of early 20th century masonry high rise buildings." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60760.
Abstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 65-67).
Early generation high rise buildings built between 1890 and World War 11 represent a technical transition between traditional load bearing masonry construction and modern curtain wall systems, and are typically referred to as 'transitional masonry buildings'. These structures comprise a large percentage of the building stock constructed in the early twentieth century. Two pertinent issues have emerged with these structures as they age. The first is the deterioration of the exterior masonry facade, which is largely a result of deficiencies in the construction method of these structures. The second issue is that it is very difficult to properly predict their structural performance because of the complicated interaction between the masonry infill and the structural frame. Underestimating or misdiagnosing the structural performance of a transitional masonry building can result in improper interventions. The aim of this thesis is to increase the understanding of the structural and facade performance of transitional masonry buildings and present methods for their analysis. A case study of a transitional masonry building is structurally analyzed using linear and nonlinear procedures to determine the contribution of the masonry infill as well as to investigate the feasibility of using simplified analytical models to predict structural performance.
by Rebecca Buntrock.
M.Eng.
16
Drucker, Andrew Donald. "PCPs for Arthur-Merlin games and communication protocols." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60160.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Includes bibliographical references (p. 59-62).
Probabilistically Checkable Proofs (PCPs) are an important class of proof systems that have played a key role in computational complexity theory. In this thesis we study the power of PCPs in two new settings: Arthur-Merlin games and communication protocols. In the first part of the thesis, we give a 'PCP characterization' of AM analogous to the PCP Theorem for NP. Similar characterizations have been given for higher levels of the Polynomial Hierarchy, and for PSPACE; however, we suggest that the result for AM might be of particular significance for attempts to derandomnize this class. To test this notion, we pose some 'Randomized Optimization Hypotheses' related to our stochastic CSPs that (in light of our result) would imply collapse results for AM. Unfortunately, the hypotheses appear over-strong, and we present evidence against them. In the process we show that. if some language in NP is hard-on-average against circuits of size 2 [omega](n), en there exist hard-on-average optimization problems of a particularly elegant form. In the second part of the thesis, we study PCPs in the setting of communication protocols. Using techniques inspired by Dinur's proof of the PCP Theorem. we show that functions f (X, y) with nondeterministic circuits of size i have -distributed PCP protocols' of proof length O(poly(m)) in which each verifier looks at a constant number of proof positions. We show a complementary negative result: a distributed PCP protocol using a proof of length f, in which Alice and Bob look at k bits of the proof while exchanging t bits of communication, can be converted into a PCP-free randomized protocol with communication bounded by In both parts of the thesis, our proofs make use of a powerful form of PCPs known as Probabilistically Checkable Proofs of Proximity. and demonstrate their versatility. In our work on Arthur-Merlin games, we also use known results on randomness-efficient soundness- and hardness-amplification. In particular, we make essential use of the Impagliazzo-Wigderson generator; our analysis relies on a recent Chernoff-type theorem for expander walks.
by Andrew Donald Drucker.
S.M.
17
LEAL, Maria Margarida Domingues da Silva Cordeiro. "Infeção por Treponema pallidum subespécie pallidum numa população de homens que têm sexo com homens (HSH): avaliação de técnica de PCR em tempo real." Master's thesis, Instituto de Higiene e Medicina Tropical, 2018. http://hdl.handle.net/10362/60860.
Abstract:
A sífilis é uma doença sexualmente transmissível, de distribuição mundial, que emergiu na Europa há mais de 500 anos. O seu agente etiológico é Treponema pallidum subespécie pallidum, que tem o ser humano como o seu hospedeiro natural. Treponema pallidum subespécie pallidum pertence ao filo das Spirochaetes, à ordem Spirochaetales, família Spirochaetaceae e ao género Treponema. Estes são microrganismos procariotas espiralados, flexíveis, filamentosos de extremidades afiladas, bacilos finos e helicoidais que apresentam uma mobilidade em “saca-rolhas” consequência da sua forma espiralada.
A infeção por Treponema pallidum evolui em quatro estádios (sífilis primária, secundária, latente e terciária) com períodos sintomáticos e assintomáticos. O diagnóstico da sífilis é difícil, principalmente durante os períodos de latência é dependente de dados clínicos e laboratoriais, uma vez que não existe nenhum teste que possibilite um diagnóstico
definitivo em todos os estádios da doença.
Os objetivos deste estudo compreendem a análise do valor diagnóstico dos testes serológicos TPHA, Determine e RPR, assim como de uma técnica de PCR em Tempo Real (PCR-TR), comparando-a também com a técnica de PCR-Multiplex (PCR-M).
De entre os testes serológicos, o Determine apresentou uma maior reatividade quando comparado com o TPHA e o RPR, apesar da discrepância observada entre os dois testes treponémicos ser mínima (2,7%). Como esperado, observou-se uma diferença significativa entre o RPR e os testes treponémicos (30,2%), que em grande parte poderá
ser devido a casos de sífilis curada. Em relação à pesquisa de DNA de T. pallidum observou-se uma taxa de concordância entre as duas técnicas de PCR (Multiplex e Tempo Real) de 92,6%. A técnica de PCR-M foi capaz de identificar DNA num maior número de amostras de sangue (8,3%) do que a técnica de PCR-TR (2,8%), mas esta última
identificou-o num maior número de amostras de lesões (26%) versus PCR-M (12%). A pesquisa de DNA de T. pallidum pela técnica de PCR-M foi efetuada utilizando dois genes (Lp 47kDa e PolA): o fragmento do gene Lp 47kDa foi identificado num número superior de amostras de lesões e de sangue do que o fragmento PolA. A técnica de PCR- -TR apenas efetuou a pesquisa do fragmento do gene PolA.
Deste estudo foi possível inferir que: a) o teste Determine demonstrou ser comparável aos testes RPR e TPHA, b) o gene Lp 47kDa pareceu ser mais fácil de identificar nas amostras estudadas, c) a identificação dos dois permite detetar DNA de T. pallidum num maior número de amostras, d) em relação à comparação das duas técnicas de PCR verificou-se que o tipo de amostra analisada tem um impacto nos resultados obtidos por esta metodologia e parece que com a técnica de PCR-TR se obtém melhores resultados em amostras de lesões do que de sangue.Syphilis is a sexually transmitted disease with worldwide distribution that emerged in Europe over 500 years ago. Treponema pallidum subspecies pallidum is the etiological agent of syphilis and its natural host is the human body. This bacterium belongs to the phylum Spirochaetales, the family Spirochaetaceae and the genus Treponema. Theses prokaryote microorganisms are motile spiral-shaped, moving with a corkscrew motion, bending and flexing, characteristic of its spiral form. Infection by Treponema pallidum occurs in four different stages (primary, secondary, latent and tertiary), evolving from one phase to the next, with symptomatic and asymptomatic periods. The diagnosis of this disease is both complex and difficult, especially during the latent phase and relies heavily on clinical and laboratory data, due to the lack of a gold standard test, able to identify the disease in all stages. The aim of this thesis was to analyse the diagnostic value of the TPHA, Determine and RPR tests, as well as the value of our Real Time Polymerase Chain Reaction (PCR- -RT), also by comparison with a PCR-Multiplex technique. Our results showed that among the serological tests, Determine had the highest reactivity when compared to both TPHA and RPR, although a slight discrepancy was observed (2,7%) between the two treponemic tests. As expected, a significant discrepancy was detected between the RPR and treponemic tests (30,2%), which was mainly attributed to treated syphilis cases. In regard, to the identification of T. pallidum DNA, an agreement of 92,6% was found between both PCR techniques (PCR-RT & PCR-M). The PCR-M technique was able to identify DNA in a larger number (8,3%) of blood samples than the PCR-RT, however this technique identified DNA in a higher number (26%) of lesion samples versus the PCR-M (12%). The PCR-M technique was used to identify the fragments of two genes (Lp 47kDa & PolA), while the PCR-RT only used the PolA gene fragment. The PolA gene fragment was identified in a lesser number of blood and lesion samples than the Lp 47kDa. In regard to this thesis results, the following conclusions were deduced: a) the Determine test proved to be comparable to the RPR and TPHA tests, b) the simultaneous identification by two genes allowed for the detection of T. pallidum DNA in a greater number of samples, c) the gene Lp 47kDa was identified more often in the samples analysed, d) when the PCR techniques were compared the type of sample analysed had a direct impact on the technique’s performance. Furthermore, it seems that with the PCR- -RT technique better results were achieved, when applied to lesion samples than blood.
18
Fernandes, Simone Pereira. "Relação do hábito alimentar e polimorfismos da MTHFR C677T com a instabilidade genômica em fumicultores gaúchos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/60560.
Abstract:
O dano genético pode ocorrer espontaneamente sob circunstâncias metabólicas normais e pode ser potencializado em situações de deficiência dietética e exposição excessiva a mutagênicos e carcinogênicos ambientais. As deficiências de ácido fólico, vitamina B6 e vitamina B12 podem levar a um aumento nos níveis e alterações na metilação do DNA. MTHFR é a enzima chave na via de metabolização do folato e o polimorfismo MTHFR C677T conduz à redução na atividade da enzima. O objetivo deste estudo foi avaliar influências da ingestão dos micronutrientes B12, B6 e folato (B9), do polimorfismo MTHFR C677T na instabilidade genômica de indivíduos expostos ocupacionalmente a pesticidas. O estudo envolveu 69 homens e 41 mulheres (n= 110) com uma idade média 42,3 ± 13,32 anos no qual 42 (38,2%) deles apresentaram peso normal, 51 (46,4%) sobrepeso e 15 (13,6%) obesidade grau I, todos os indivíduos da amostra são fumicultores de Venâncio Aires e Santa Cruz do Sul (estado do Rio Grande do Sul, Brasil). A genotipagem do polimorfismo MTHFR C677T foi realizada pelo método PCR-RFLP. Os dados de dano de DNA foram avaliados pelos biomarcadores de exposição ocupacional ensaio cometa e micronúcleo. O status nutricional foi avaliado com base na média de 3 recordatórios de 24 horas (coletados em 3 dias não consecutivos , incluindo um final de semana em um intervalo de 4 meses). A ingestão dos micronutrientes foi estimada usando o programa nutricional Food Processor SQL 10.9. Não foram encontradas diferenças significativas entre idade e tempo de exposição a pesticidas para os parâmetros analisados. Encontramos aumento na frequência de micronúcleo de linfócitos em indivíduos com ingestão inadequada de folato e vitamina B12, apresentando diferença significativa (P = 0,030) e (P = 0,014) respectivamente quando comparados com os indivíduos com ingestão adequada. Dano de DNA não mostrou resultados significativos quando relacionados com tabagismo, anos de exposição, IMC e polimorfismo MTHFR C677T. A correlação entre dano do DNA, ingestão de folato, B6 e B12 e o polimorfismo MTHFR não apresentou significância. Em conclusão, nossos resultados indicaram que a adequação de folato para valores ≥ 320 μg /dia e vitamina B12 ≥ 2,0 μg /dia, nesta amostra exposta, estaria protegendo da ação mutagênica dos pesticidas. A dieta adequada, tanto em folato quanto em vitamina B12 poderia estar auxiliando em um reparo de DNA adequado sugerindo um fator de proteção nesses indivíduos.Genetic damage can occur spontaneously under normal metabolic circumstances and can also be present in situations of dietary deficiency or inadequate intake of nutrients and excessive exposure to environmental mutagens. The purpose of this study was to evaluate the influence of the intake of micronutrients B12, B6 and folate and of polymorphism MTHFR C677T in the induction of DNA damage in individuals exposed to pesticides. The study involved 69 men and 41 women who were tobacco farmers in the region of Venâncio Aires (State of Rio Grande do Sul, Brasil). DNA damage was analyzed by the Comet Test and Micronucleus Test (MN); dietary intake was evaluated based on the mean of three 24-hour Diet Recall questionnaires. The nutrient intake data were computerized and estimated in the Food Processor SQL 10.9 program. The DNA damage results showed a significant increase in MN frequency in the lymphocytes of individuals who had an inadequate intake of folate and B12 (P = 0.030 and P = 0.014, respectively). No significant association was found between DNA damage and polymorphism MTHFR C677T. Correlations between DNA damage and polymorphism MTHFR C677T and nutrient intake were not significant. In conclusion, our results indicated that the adequate intake of folate (≥ 320 μg /day) and vitamin B12 (≥ 2,0 μg /day) can provide protection from the mutagenic action of pesticides. A dietary adaptation of folate and B12 can ensure adequate repair, showing that diet is a protective factor in this population.
19
Ramos, Graziele Pereira. "Estudo químico de diferentes acessos de trevo-vermelho (Trifolium pratense L.) e atividades biológicas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/60660.
Abstract:
O trevo-vermelho (Trifolium pratense L.), uma das leguminosas forrageiras mais utilizadas na agricultura mundial, contém as isoflavonas formononetina e biochanina A, e em menores concentrações daidzeína e genisteína. Estes compostos têm ganhado muito interesse devido aos relatos de seus benefícios à saúde humana. Recentemente, no ano de 2009, esta espécie foi incluida na lista da Relação Nacional de Plantas Medicinais de Interesse ao SUS (RENISUS) que contém plantas medicinais com potencial de gerar produtos para serem produzidos e distribuídos pelo SUS. Mas é importante destacar que não existem estudos de quantificação de isoflavonas em plantas de trevo-vermelho cultivados no Brasil. Os objetivos deste trabalho foram validar método de análise de amostras de trevo-vermelho por Cromatografia Líquida de Alta Eficiência (CLAE); quantificar quatro isoflavonas em 78 acessos de trevo-vermelho; verificar as modificações sazonais na concentração de três acessos de trevo-vermelho; aumentar os níveis de isoflavonas através de melhoramento genético; e determinar a atividade anti-inflamatória in vivo e in vitro e de atividade de inibição da acetilcolinesterase de um extrato seco de trevo-vermelho. Para analisar as plantas por CLAE, estas foram hidrolisadas, separadas por diclorometano, e ressuspendidas em metanol. O método de CLAE usado foi validado. As isoflavonas (daidzeína, genisteína, formononetina e biochanina A) foram quantificadas em 78 acessos de trevo-vermelho, os conteúdos das agliconas (expressos em μg/g de planta seca, n=3) destes compostos variaram entre 0,00 a 137,91 para daidzeína; 14,70 a 516,51 para genisteína; 452,97 a 28548,65 para formononetina; e 1967,64 a 20145,27 para biochanina A, e a concentração total de isoflavonas variou entre 9,81 e 36,36 mg/g. O estudo sazonal mostrou que a concentração total das isoflavonas não difere entre as estações, mas verifica-se que na primavera (quando o trevo-vermelho está no estágio reprodutivo) se observam concentrações inferiores, e no inverno (quando a planta está no estágio vegetativo) são encontradas concentrações mais elevadas. No estudo de melhoramento genético foi possível observar um aumento na concentração total de isoflavonas. A atividade anti-inflamatória in vitro foi medida através da mobilização de leucócitos, pelo ensaio de quimiotaxia na câmara de Boyden. A atividade anti-inflamatória in vivo foi avaliada pelo teste de edema de pata de rato induzido por carragenina. Os resultados do teste anti-inflamatório in vitro mostram que houve significante inibição da migração dos leucócitos nas concentrações de 100,0 (94,73% de inibição), 50,0 (95,39% de inibição), 25,0 (94,73% de inibição), 10,0 (84,68% de inibição) e 5,0 (78,75% de inibição) μg/mL de extrato seco de trevo-vermelho. O teste anti-inflamatório in vivo demonstrou significante atividade nas doses testadas, 100 e 50 mg/kg de extrato seco de trevo-vermelho. O percentual médio de inibição do edema foi 63,37%. O teste da inibição da acetilcolinesterase não demonstrou atividade. Os resultados deste estudo sugerem que se pode produzir plantas com concentrações mais elevadas de isoflavonas para a produção de fitomedicamentos com maior qualidade, e o extrato de trevo-vermelho pode ser adequado para o tratamento de doenças inflamatórias.Red clover (Trifolium pratense L.) is one of the most utilized forage legume in the world agriculture and contains the isoflavones formononetin and biochanin A, and in smaller concentration daidzein and genistein. These compounds have gained a high interest due to their human health benefits. Recently this species was included in the list of Relação Nacional de Plantas Medicinais de Interesse ao SUS (RENISUS) which contains medicinal plants that have potential to generate products to be produced and distributed by SUS. But it is important to highlight that does not exist any study of isoflavones quantification in red clover plants cultivated in Brazil. The aims of this work were to validate a method to analize red clover samples by High Performance Liquid Cromatography (HPLC); to quantify four isoflavones compounds in 78 red clover accessions; to verify seasonal modifications in the isoflavone concentration of three red clover accessions; to increase isoflavones levels through plant breeding; and to determine in vivo and in vitro anti-inflammatory activity, and inhibitory activity of acetylcholinesterase of a red clover dry extract. To analyze the plants by HPLC, they were hydrolyzed, separated by dichloromethane, and resuspended with methanol. The HPLC method used was validated. Isoflavones (daidzein, genistein, formononetin and biochanin A) were quantified in 78 red clover accessions, the aglycone contents (expressed in μg/g of dry material, n=3) of these compounds varied from 0.00 to 137.91 to daidzein; 14.70 to 516.51 to genistein; 452.97 to 28548.65 to formononetin; and 1967.64 to 20145.27 to biochanin A, and the total isoflavone concentration ranged between 9.81 and 36.36 mg/g. The seasonal study showed that the total concentration of isoflavones is not statistically different at different seasons, but is possible to verify that at spring (when red clover is at reproductive stage) we could observe the lowest concentration, and at winter (when red clover is at vegetative stage) we found the highest concentration. In the breeding study we could observe an increase in the total concentration of isoflavones. The in vitro anti-inflammatory activity was measured towards by leucocytes mobilization, by chemotaxis assay in Boyden´s chamber. The in vivo anti-inflammatory activity was tested by a carrageenan-induced rat paw edema test. The results of anti-inflammatory in vitro test showed that there was a significant inhibition of leukocyte migration at concentrations of 100.0 (94.73% of inhibition), 50.0 (95.39% of inhibition), 25.0 (94.73% of inhibition), 10.0 (84.68% of inhibition) and 5.0 (78.75% of inhibition) μg/mL of red clover dry extract. The in vivo anti-inflammatory test demonstrated significant activity in the tested doses, 100 and 50 mg/kg of red clover dry extract. The average of edema inhibition percentage was 63.37%. The inhibition of acetylcholinesterase test did not show activity. The results of this study suggest that we can select or produce plants with higher concentrations of isoflavones to produce phytomedicines with higher quality, and the red clover extract might be suitable for the treatment of inflammatory diseases.
20
Ribeiro, Vera Lucia Sardá. "Estudo do mecanismo de ação da atividade acaricida de Calea serrata (Asteraceae) em Rhipicephalus (Boophilus) microplus e da sua toxicidade em roedores." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/60960.
Abstract:
O extrato n-hexano de Calea serrata demonstrou atividade acaricida contra larvas de Rhipicephalus (Boophilus) microplus e R. sanguineus. A enzima acetilcolinesterase (AChE), responsável por hidrolisar a acetilcolina nas sinapses colinérgicas, tem sido alvo de pesticidas e sua inibição pelos organofosforados levam à paralisia e morte de artrópodes. O uso intensivo de acaricidas / inseticidas tem provocado resistência em artrópodes, a qual pode estar relacionada com maior atividade de enzimas de detoxicação, como a glutationa-S-transferase (GST). O objetivo do presente estudo foi avaliar a atividade acaricida do componente isolado do extrato n-hexano, o precoceno II, e do óleo essencial de C. serrata, assim como, determinar a composição química do referido óleo. Com intuito de compreender o mecanismo de ação acaricida do extrato n-hexano de C. serrata, foi investigado o efeito deste extrato sobre a atividade in vitro da AChE em larvas de R. microplus e em estruturas cerebrais de ratos Wistar machos, bem como sobre a modulação da atividade da GST em larvas de R. microplus. O óleo essencial e o precoceno II, o composto isolado, mostraram atividade larvicida. O óleo essencial apresentou diferentes sesquiterpenos em sua constituição química, além de precoceno II. O extrato nhexano de C. serrata inibiu significativamente a atividade in vitro da AChE em larvas de R. microplus e em estruturas cerebrais de ratos. O extrato n-hexano de C. serrata inibiu significativamente a atividade in vitro da GST. Compostos do extrato n-hexano de C. serrata podem ser potenciais inibidores de AChE e de GST, os quais podem contribuir para a sua toxicidade para os carrapatos. Considerando que o aumento da atividade da GST poderia reduzir a eficiência de carrapaticidas, é possível supor que C. serrata possa ser usada como um adjuvante no controle de R. microplus. Os resultados obtidos também suportam a possibilidade de que a inibição da acetilcolinesterase seja um possível mecanismo de ação do extrato n-hexano de C. serrata.It has been demonstrated that the n-hexane extract of Calea serrata had acaricidal activity against larvae of R. microplus and R. sanguineus. Acetylcholinesterase (AChE), an enzyme that hydrolyses acetylcholine at cholinergic synapses, is a target for pesticides and its inhibition by organophosphates leads to paralysis and death of arthropods. Extensive uses of acaricides/inseticides have induced resistance in arthropods, which can be related to higher activity of detoxification enzymes, such as glutathione-S-transferase (GST).The aims of the present study were to evaluate the acaricide activity of isolated constituent of n-hexane extract, the precocene II, and the essential oil of C.serrata, in addition to determine the chemical composition of essential oil. In order to understand the mechanism of the acaricidal action of C. serrata n-hexane extract, we investigated the effect of this extract on in vitro anticholinesterase activity of larvae from R. microplus and in brain structures of male Wistar rats, as well as, we investigated the effect of C. serrata on GST activity of larvae from R. microplus.The essential oil and the isolated compound, precocene II, showed larvicidal action. Several sesquiterpenes were detected in the essential oil of C. serrata. The n-hexane extract significantly inhibited in vitro acetylcholinesterase activity in R. microplus larvae and rat brain structures. The n-hexane extract of C. serrata inhibited significantly GST activity. Compounds of n-hexane extract from C. serrata may be potential inhibitors of AChE and GST, which may contribute to its tick toxicity. Considering that higher GST activities would reduce the efficiency of the pesticides, we can also suppose that C. serrata may be at least used as an adjuvant in tick control. The results support that inhibition of acetylcholinesterase is a possible mechanism of action of hexane extract at C. serrata.
21
Aletter, Candice Joy. "Protection of agency workers in South Africa : an appraisal of compliance with ILO and EU Norms." Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/60060.
Abstract:
This thesis is a policy-based study of the regulation of agency work in South Africa. It is set against the contextual background of a recent legislative overhaul and an increase in the number of precarious workers. The study aims to appraise the extent to which the South African regulatory framework complies with international norms in respect of agency work. The research considers how German and Namibian regulation might improve the current model of the regulation of agency work in South Africa.
The study identifies the purpose of labour law in South Africa as offering diversified rights as well as being economic in nature. The premise upon which the thesis is based is a social justice approach to the function of labour law. An analysis of ILO and EU regulations on agency work is conducted, and identifies a combined list of norms in respect of the protection of agency workers. South Africa?s labour law policy approach is explored together with the amended regulation on agency work. A comparison is drawn with foreign countries? regulations and policy approaches: the appraisal identifies shortcomings in South Africa?s regulatory model.
The study focuses on the evolutionary improvement of agency workers? protection based on international approaches. The research culminates by formulating an amended model for the regulation of agency work in South Africa, in which these proposed adaptations seek to remedy the shortcomings which were observed in the appraisal process.Thesis (LLD)--University of Pretoria, 2016.
Mercantile Law
LLD
Unrestricted
22
Gouws, Nandel. "Wideband reflectance for assessing middle ear functioning for at-risk neonates in the NICU." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60360.
Abstract:
Hearing loss in early childhood and infancy often goes undetected because it exhibits no obvious indication and symptoms. The primary aim of newborn hearing screening is to detect permanent hearing loss. Since otoacoustic emissions (OAE) and automated auditory brainstem response (AABR) are sensitive to hearing loss, they are often used as screening tools. On the other hand, these screening tests can be affected by transient outer ear and middle ear conditions that are often present at birth. This is an especially characteristic state of affairs for NICU neonates. These false positive results may render screening programmes inefficient and can lead to increased parental anxiety. Wideband acoustic immittance (WAI) has shown potential for accurate assessment of middle ear function in neonates, and is therefore recommended as an adjunct tool for newborn hearing screening programmes. The main aim of the study was to determine the feasibility of using WAI in NICU neonates in terms of tone and click stimuli.
Testing was conducted in the NICU units of three private hospitals in Pretoria. As part of the selection criteria all the neonates had to pass both DPOAE and AABR screenings before they were included in the study. In total, 56 NICU infants (106 ears) with a gestation age of between 32 and 37 weeks and a mean gestational age of 35.6 weeks who passed both DPOAE and AABR hearing screens in one or both ears were selected. For WAI measurements there were two measurements, one for each channel in the probe (chirp and tone stimuli). Normative regions were defined across the wideband reflective spectrum for both tone and chirp stimuli and for integrated frequency ranges. The chirps and tone stimuli compared relatively well with each other at the 90th percentile with the same amount of reflectance across all frequencies. The median reflectance reached a minimum of 0.67 at 1-2 kHz but increased to 0.7 below 1 kHz and 0.72 above 2 kHz for the tone stimuli. For chirp stimuli the median reflectance reached a minimum of 0.51 at 1-2 kHz but increased to 0.68 below 1 kHz and decreased to 0.5 above 2 kHz.
Results of this study identified WAI patterns that had not previously been reported in the literature. High reflective values were obtained across all frequency ranges, especially in the frequency ranges below 3 kHz and above 4 kHz. The age of the neonates when tested (mean gestational age 35.6 weeks, with a standard deviation of 1.6) might have influenced the results. The neonates in this study were of a very young age compared to the ages of the infants in previous studies on WAI. Environmental noise in NICU might have influenced the results. Additional research is required to investigate WAI testing in ears with and without dysfunction.Dissertation (M Communication Pathology)--University of Pretoria, 2016.
Speech-Language Pathology and Audiology
M Communication Pathology
Unrestricted
23
Stols, Maria Jacoba. "The influence of pro-environmental motivation and intent on female consumers' apparel disposal behaviour." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60860.
Abstract:
The apparel and textile industry plays an enormous role in the depletion of natural resources, pollution and other environmental problems. Pro-environmental efforts should thus be encouraged in all stages of the apparel supply chain, but also more specifically at the disposal stage during which consumers should be encouraged to adopt eco-friendly options such as donating, recycling and/ or reselling apparel. The aim of this study was to explore and describe female consumers' pro-environmental disposal motivation and intent regarding apparel in the South African context. The hypothesis and conceptual framework for this study was based on a combination of the Theory of Planned Behaviour (TPB) and the Norm Activation Theory's (NAT) constructs as the underlying motivational factors that contribute to pro-environmental disposal intent. The research was carried out in the Gauteng province, South Africa. The sample comprised of 315 female consumers; female consumers were of particular interest since they tend to engage in pro-environmental behaviour to a larger extent than males. This quantitative study used a cross-sectional survey design for which a Qualtrics web-based questionnaire was developed. Data was captured and coded to be further subjected to descriptive and inferential analyses.
The findings indicated that most respondents are aware of environmental consequences related to the disposal of apparel. Social norms influenced respondents' personal norms, as well as their behavioural intent to make pro-environmental decisions regarding the disposal of apparel. It seems that consumers' attitudes also influence their pro-environmental behavioural intent significantly. In contrast, perceived behavioural control had a weaker influence on pro-environmental intent. The theoretical contribution of this study relates to the relevance of TPB and NAT constructs in the local context. In so far as practical implications are concerned, it was concluded that government and businesses should get involved in promoting pro-environmental apparel disposal options and educating consumers about the benefits of disposing apparel in a pro-environmental manner.Die klere en tekstiel bedryf speel 'n noodsaaklike rol in die vermindering van natuurlike bronne, besoedeling en ander omgewingsprobleme. Pro-omgewings pogings moet dus aangemoedig word in alle stadiums van die klere voorsienings kettings, maar meer spesifiek ook in die wegdoen fase waarin verbruikers aangemoedig moet word om omgewings vriendelike opsies te oorweeg soos skenking, herwinning en herverkoping. Die doel van hierdie studie was vroulike verbruikers se pro-omgewings klere beskikkings motivering en bedoeling te verken en beskryf in 'n Suid Afrikaanse konteks. Die hipotese en konseptuele raamwerk vir hierdie studie is gebaseer op 'n kombinasie van die Teorie van Beplande Gedrag (TPB) en die Norm Aktiverings Teorie (NAT) se konsepte as die onderliggende motiverende faktore wat bydra tot verbruikers se pro-omgewings wegdoen voorneme. Die navorsing was uitgevoer in Gauteng provinsie, Suid Afrika. Die steekproef het uit 315 vroulike verbruikers bestaan; vroulike verbruikers was van besondere belang aangesien hulle geneig is om betrokke te raak in pro-omgewings gedrag tot 'n groter mate as mans. Hierdie kwantitatiewe studie het 'n deursnit opname-ontwerp gebruik waarvoor 'n Qualtrics web-gebaseerde vraelys ontwikkel is. Die data was ingevoer en verder gekodeer om beskrywende en inferentiële statistiek ontledings te ontwikkel. Die bevindings het aangedui dat die meeste respondente bewus is van hoe die wegdoen van klere die omgewing beïnvloed. Sosiale norme het die respondente se persoonlike norme beïnvloed, asook hul gedragspatrone intensie om pro-omgewings besluite te maak ten opsigte van die wegdoen van klere. Dit blyk dat die houdings van verbruikers hul pro-omgewings gedrags intensie ook aansienlik beïnvloed. In teenstelling hiermee, het waargeneemde gedrags beheer 'n swakker invloed op pro-omgewings voorneme. Die teoretiese bydrae van hierdie studie het betrekking tot die toepaslikheid van TPB en NAT konsepte in 'n plaaslike konteks. In terme van praktiese implikasies, was die gevolgtrekking dat die regering en besighede betrokke moet raak in die bevordering van pro-omgewings wegdoen opsies en die opvoeding van verbruikers oor die voordele van die afhandeling van klere op 'n pro-omgewings wyse.
Dissertation (MConsumer Science)--University of Pretoria, 2016.
Consumer Science
MConsumer Science
Unrestricted
24
Mkhondo, Sello Samuel. "The influence of leadership and management on teacher retention in Mpumalanga schools." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60960.
Abstract:
Managing teacher retention is important for ensuring that quality teaching and learning take place in schools. Principals play an enormous role in creating conditions that are conducive to educative teaching and learning in the school. If principals can ensure that conditions in the schools are conducive for job satisfaction, then most teachers would not leave the school. Teacher satisfaction ultimately leads to commitment in school work. The main aim of this study was to investigate the influence of leadership and management on teacher retention in the Tweefontein South Circuit schools in the Mpumalanga Province. The assumption was that if teachers are satisfied in their jobs, then they will be retained in the school. Teacher attrition is, in most instances, ascribed to poor working conditions such as work overload, poor interpersonal relations, poor salaries and lack of support from the school management team. Although educators employed in schools acquired the best training at universities or training colleges, they still struggle financially and have a lot of debts. To achieve the aim of the study, a qualitative research approach was followed to collect data through semi-structured interviews. Purposive sampling was used to select participants with defining characteristics that make them the holders of the data needed for the study. Data was collected from principals, deputy principals, departmental heads and post level one teachers. The collected data was analysed and a thematic analysis was carried out to generate themes that addressed the study's problem. The responses from participants revealed that the school leadership comprising of the principals, deputy principals and HoDs encounter serious challenges in retaining teachers in schools. Findings revealed that SMTs should support teachers by involving them in decisions that enable teachers to experience job satisfaction. Although all school leaders try to motivate and support teachers not to resign through leadership, the motivation has yielded meagre results. There is absolutely nothing or little that school leadership can do to retain a teacher who resigns in order to access his or her pension fund after experiencing financial difficulties. Recommendations were that the school leadership should involve teachers in making decisions that will ensure teacher job satisfaction and that the department of education should also establish mechanisms in which teachers would be allowed to access part of their pension fund should they experience financial difficulties before reaching the retirement age.Dissertation (MEd)--University of Pretoria, 2016.
Education Management and Policy Studies
MEd
Unrestricted
25
Azevedo, Guerra Elzivir. "Trübemitführung feiner hydrophiler Teilchen in mechanischen Flotationsapparaten und deren Reduzierung." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:swb:105-2498846.
Abstract:
Ziel der vorliegenden Arbeit ist es, mit Hilfe einer neu entwickelten Methode zur getrennten Bestimmung des Feststoffausbringens durch Trübemitführung und Heterokoagulation die Wirkung einiger wichtiger Prozessparameter zu bewerten. Darüber hinaus ist der Einfluss der Modifizierung des Suspensionszustandes (Änderung der Turbulenzintensität) bzw. des Flockungszustandes hydrophiler Teilchen auf die Trübemitführung feiner hydrophiler Teilchen in mechanischen Flotationsapparaten aufzuklären. Die Ergebnisse der vorliegenden Arbeit sind ein Beitrag zur Erweiterung der Kenntnisse über die Mechanismen der Trübemitführung in mechanischen Flotationsapparaten. Sie liefern wesentliche neue Hinweise zur Steuerung und Reduzierung der Trübemitführung. Aus den Schlussfolgerungen der Arbeit können wichtige Maßnahmen und Kriterien zur Optimierung der Feinstteilchenflotation bei der Aufbereitung komplex zusammensetzter, wertstoffarmer Rohstoffe und für das Recycling von festen Abfällen abgeleitet werden.
26
Østhus, Per Magnus. "Concurrent operation of Bluetooth low energy and ANT wireless protocols with an embedded controller." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14040.
Abstract:
With the introduction of low-power wireless technologies, new applicationsin the healthcare, fitness and home entertainment markets emergethrough the use of ultra low-power sensors. These devices are designed torun for years on a single coin-cell battery.ANT and Bluetooth Low Energy are two low-power protocols that emergeas competitors in this market. The ability to combine these in a single systemnot only takes away the element of choice from the manufacturers, but alsoprovides compatibility between the two protocols. An ANT-enabled devicecan be coupled to a Bluetooth network, with the benefit of connecting tonon-ANT central devices, such as smartphones, tablets and laptops.In this thesis, the co-existence of these two protocols is discussed. Animplementation with two distinct radios for each protocol, controlled by asingle embedded microcontroller, is presented. The implementation is testedwith regards to packet loss with a simple test application. Test results showthat the obtained packet loss cannot be correlated to the co-existence of thetwo protocols.
27
Colom, Fajula Xavier. "Caracterització microestructural i mecànica de compòsits hdpe/fibres lignocel.lulòsiques." Doctoral thesis, Universitat Politècnica de Catalunya, 1999. http://hdl.handle.net/10803/6060.
Abstract:
A partir de polietilè d'alta densitat i de fibres lignocel·lulòsiques provinents del trèmol (Populus tremula) s'han obtingut uns materials amb propietats úniques denominats compòsits. Aquests compòsits, amb un màxim de 40% de fibres lignocel·lulòsiques han estat tractats i modificats amb diferents agents (silà A-174 i epolè C-18) per millorar la compatibilitat entre la matriu de polietilè i el reforç fibrós. En una primera etapa les fibres lignocel·lulòsiques han estat pretractades amb cada un dels diferents tipus d'agents d'adhesió utilitzats i comentats prèviament, per seguidament barrejar aquestes fibres (en proporcions del 10, 20, 30 i 40%) amb la matriu d'HDPE.
Una vegada els dos components s'han homogeneïtzat, es sotmeten a un procés de mòlta per aconseguir, mitjançant compressió, les provetes corresponents. Finalment, el conjunt de provetes ha estat exposat a condicions climàtiques dràstiques (baixa temperatura i fatiga tèrmica, dues característiques significatives de l'hivern canadenc) durant períodes variables de temps (0, 15, 30, 60 i 90 dies).
Per tal d'avaluar tots i cada un dels paràmetres més significatius d'aquests compòsits, s'ha fet una caracterització orientada en dues vessants: estudi de la compatibilitat entre components del compòsit i estudi dels canvis estructurals que pateixen els compòsits degut a fenòmens d'envelliment provocats per exposició a les condicions climàtiques prèviament comentades.
L'estudi de compatibilitat es fonamenta en les possibles interaccions que s'originen entre els dos components en funció del tipus de tractament al que ha estat sotmès el compòsit (silà i epolè). Per valorar aquestes interaccions, s'han estudiat diferents propietats mecàniques, com ara la resistència a la tracció, el mòdul d'elasticitat, la deformació a trencament, la resiliència i la tenacitat, mitjançant una màquina universal d'assaigs. Tanmateix també s'ha fet una caracterització espectrefotomètrica FT-ir per comprovar els diferents mecanismes d'adhesió que actuen en la interfase fibra- matriu en funció del tipus de tractament i una caracterització morfològica, utilitzant la tècnica de microscòpia electrònica de rastreig (SEM). Amb els resultats obtinguts de la caracterització espectrefotomètrica, també s'ha realitzat un seguiment de la influència que cada component fa en la modificació del grau de cristal·linitat de l'altre.
L'estudi dels canvis estructurals que pateixen els compòsits degut a fenòmens d'envelliment s'ha fet partint de l'evolució de les propietats mecàniques bàsiques en funció dels diferents períodes d'exposició, on s'han caracteritzat els mateixos paràmetres definits anteriorment. Mitjançant valoració espectrefotomètrica s'han mesurat els canvis microestructurals (principalment de configuració), així com les modificacions en el grau de cristal·linitat que han tingut lloc sobre cada un dels diferents components del compòsit.
Cal afegir que les possibilitats que ofereix la tècnica espectrefotomètrica FT-ir ha permès dur a terme la realització d'aquesta tesi. L'estudi dels canvis en la microestructura dels compòsits esdevinguts a partir dels fenòmens prèviament esmentats no hauria pogut fer-se sense la possibilitat d'un processament adequat dels espectres, així com d'una subtracció espectral que permet la detecció de moltes bandes complexes i difícils de detectar mitjançant altres tècniques d'anàlisi.
Los materiales compuestos se han obtenido a partir de polietileno de alta densidad y fibras lignocelulósicas que provienen del alamo temblón. Estos materiales con un máximo del 40% de refuerzo lignocelulósico han sido tratadas y modificadas con distintos tipos de agentes de acoplamiento (Silano A-174 y epoleno C-18) para mejorar la compatibilidad entre la matriz y el refuerzo.
Las fibras tratadas previamente con cada uno de los distintos tipos de agentes de adhesión utilizados, se mezclan en distintas proporciones de las mismas (10,20,30 y 40%) con la matriz de HDPE.
Una vez ambos componentes se han homogenizado se someten a un proceso de molturación para obtener probetas tipo halterio mediante compresión. Estas probetas se han sometido durante distintos períodos de tiempo (hasta 90 días) a condiciones de exposición drásticas (baja temperatura y fatiga térmica, características significativas del invierno canadiense).
Para evaluar los parámetros más significativos de estos materiales compuestos se ha caracterizado la compatibilidad entre la matriz y el refuerzo, asimismo también se han estudiado los cambios estructurales que sufren estos materiales debido a fenómenos de envejecimiento provocados por la exposición de los mismos a las condiciones climáticas previamente comentadas.
Els estudio de compatibilidad se centra en las posibles interacciones que se originen entre ambos componentes en función del tipo de tratamiento al que se ha sometido dicho material compuesto (silano y epoleno). Para valorar las interacciones que se generen entre ambos componentes, se ha ensayado distintas propiedades mecánicas (resistencia a tracción, módulo de elasticidad, deformación a rotura, resilencia y tenaciadad, utilizando la máquina universal de ensayos. Asimismo, también se ha caracterizado mediante espectroscopia de infrarrojo (FTIR) los posibles mecanismos de adhesión que tienen lugar entre la matriz y el refuerzo en función del tipo de tratamiento, asi como la caracterización morfológica utilizando la técnica de microscopía electrónica de barrido (SEM). A partir de los resultados obtenidos se ha podido seguir la influencia que tiene cada componente en la modificación de los respectivos grados de cristalinidad.
El estudio de los cambios estructurales a los que se han visto sometido los distintos materiales compuestos, debido a fenómenos de envejecimiento, se ha realizado mediante el seguimiento de la evolución de las propiedades mecánicas en función de los distintos períodos de exposición. Mediante valoración espectofotométrica se han medido los cambios micorestrucutrales (cambios de configuración), así como las modificaciones en el grado de cristalinidad sobre cada uno de los componentes de material compuesto.
Composite materials have been obtained from high density polyethylene (HDPE) and lignocellulosic fibers from aspen wood. These materials with a maximum of 40% of lignocellulosic reinforcement have been treated and modified with different types of coupling agents (Silane A-174 and epolene C-18) to improve the compatibility between the matrix and the reinforcement.
Four contents (10.20.30 and 40%) of fibers treated previously with each one of the different types of adhesion or coupling agents, are mixed with HDPE matrix.
The above mixture was compression-molded into dog-bone shaped tensile test specimens. The molding temperature was slowly raised to 150ºC and samples were held at this temperature for 20 min. Then the samples were slowly cooled to room temperature keeping constant pressure during cooling. These test specimens have been submitted during different periods of time (up to 90 days) to drastic conditions of exposition (low temperature and thermal stress, main characteristics of the Canadian winter).
In order to evaluate the most significant parameters of these composite materials, we have studied two ways: the compatibility between both components: matrix and reinforcement and the structural changes to composites due to phenomena of aging caused by the exposition of these materials to the drastic climatic conditions previously commented.
The study of compatibility has been centered in the possible interactions that are originated between both components as a function of lignocellulosic fiber pretreatment. In order to evaluate the interactions that are generated between both components, different mechanical test has been tested (tensile strength, elasticity modulus, deformation at break, resilence and toughness) by mean an Instron Testing Machine. Moreover, the possible mechanisms of adhesion that take place between the matrix and the reinforcement as a function of different pretreatments has been characterized by means infrared spectroscopy (FTIR), and by the morphologic characterization using the scanning electronic microscopy (SEM). From the obtained results it has been possible to follow the influence that has each component in the modification of the respective degrees of crystallinity.
The study of the structural changes of different composite materials, due to aging phenomena, has been analized by means of the pursuit of the evolution of the mechanical properties based on the different periods of exposure time. Furthermore the microstructural changes (basically configurational and crystallinity) has been evaluated by means of spectroscopy technique.
The obtained results indicate that the macroscopic properties of the composite materials must depend on the lignocellulosic fiber content and whether or not a coupling agent is used. SEM micrographs of fracture surfaces show that the addition of coupling agents enhances their dispersion in the continuous HDPE phase. They also show that the silane coupling agent facilitates the direct contact between the lignocellulosic fibers and HDPE matrix more than untreated and epolene treated composites do. The tensile strength depends on both the lignocellulosic fiber content and the type of coupling agent used. The other mechanical properties (elasticity modulus, elongation at break and toughness) mainly depend on the lignocellulosic fiber content and, to a lesser extent, on the presence of a coupling agent. Silane-treated composites show the best mechanical performance as a consequence of significant interactions at the interface between the HDPE matrix and the lignocellulosic fibers.
The differences observed between the various composites studied are explained by means of different adhesion mechanisms. Interdiffusion takes place in untreated composites; multiple mechanism of adsorption-wettability, interdiffusion and, to a lesser extent, chemical bonds take place in epolene treated composites, and finally, the adhesion in composites modified with silane is mainly a chemical mechanism of covalent bonds.
28
鈴木, 慎太郎, and Shintaro Suzuki. "臓器移植制度の理論（三） ： 臓器移植の制度化にともなう実践的諸問題の法哲学的考察." 名古屋大学大学院法学研究科, 2004. http://hdl.handle.net/2237/6060.
29
Boissonneault, Julie. "Représentations de l'enseignement et de l'apprentissage par des professeurs universitaires utilisant des médias interactifs à distance." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6060.
Abstract:
Depuis de nombreuses années, l'intégration des nouvelles technologies de l'information et de la communication (NTIC) fait l'objet d'études diverses dans le milieu scolaire, variant de leur utilisation comme outil pédagogique en salle de classe à leur «impact» sur l'enseignement et sur l'apprentissage. Si les NTIC se sont taillées une place dans les pratiques pédagogiques à l'élémentaire et au secondaire, la question a été tout autre au niveau universitaire. Cette recherche se veut d'être un regard sur les représentations des professeurs enseignant à distance en faisant appel aux médias interactifs et numériques à l'université. Dès l'abord, nous proposons l'hypothèse que les NTIC nous interpellent à restructurer nos façons de faire.
La problématique et le cadre théorique permettent un regard rapide sur les NTIC, qui appellent à un nouvel ordre sociétal. Nous nous tournons ensuite vers le milieu universitaire où leur présence bouleverse les repères spatiotemporels en usage. Afin de mieux comprendre les enjeux, nous nous tournons vers la formation à distance qui, en raison de son historique et du fait qu'elle est hautement tributaire des médias, possède une feuille de route incontournable à ce sujet. Ce survol permet ainsi de mieux arrimer les questions entourant l'enseignement et l'apprentissage médiatisés sur la scène universitaire et la façon dont les professeurs se les représentent. Cette composante théorique se termine sur la représentation proposée par le triangle pédagogique et sur la vision paradigmatique qui a cours chez grand nombre d'auteurs.
Pour répondre aux questions que nous posons en matière de représentations sociales, puis, par ricochet, des changements que suscitent les NTIC en enseignement et en apprentissage, nous avons procédé par entretien semi-dirigé, ce qui a permis la collecte de données dialogiques auprès de professeurs enseignant à distance et faisant appel aux nouveaux médias. La recherche s'inscrit ainsi dans une démarche interprétative.
L'analyse des données recueillies fait ressortir, non seulement ce que représentent l'enseignement et l'apprentissage pour des professeurs, mais également leur posture à l'égard de la formation à distance et de l'intégration des NTIC sur la scène universitaire. L'imagerie qui se dessine, tissée à même leurs discours individuels, relève de l'ordre du collectif.
La trame esquissée permet de revoir les limites de la vision paradigmatique ainsi que de mieux comprendre comment les propos des répondants se traduisent dans la vision du triangle pédagogique. Ce faisant, il est possible de jeter un nouveau regard sur les relations qui se tissent entre professeur, étudiant et savoir. Ces relations sont largement tributaires de trois grands thèmes: la pensée critique comme visée de l'enseignement et de l'apprentissage, l'importance de l'interaction réciproque dans la construction du savoir, et la vulnérabilité des professeurs face aux NTIC.
30
Altice, Jessica Mae. "“You Can Fight Logic…But You Can’t Fight God”: The Duality of Religious Text and Church as Community for White Lesbians in Appalachian and Rural Places." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6060.
Abstract:
Much of the research conducted on lesbians and place focuses on women who live in urban areas or highlights how participants wish to live in urban areas. Knowing that there are lesbians who live in rural and Appalachian areas that do not wish to leave to urban areas, this research examines participants’ experiences living in those places. Participants discuss how religion is a socially circulating meaning system in the places they live and it dictates much of social life. I argue that religion has a two-fold meaning for participants: one, it is a religious text that is used as a social control mechanism in the lives of the women and two, it is church as community, in which the participants use church spaces to both make community among themselves as well as be a part of the larger community in their towns. This research adds to the narratives of rural lesbian women and available ways of occupying spaces by breaking down a binary of common cultural ideas about place and sexuality.
31
Singh, Pawanbir. "Enabling late-stage translation of regenerative medicine based products." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6060.
Abstract:
The primary aim of the thesis is to contribute to demonstrating how established and emerging science in the regenerative medicine (RM) domain can be translated into profitable commercial practice, and generate clinically- and cost-effective therapies. It achieves this by exploring and assessing underlying economics, including investment readiness and economic assessment, exploring regulatory and reimbursement frameworks, developing stem cell culture systems and assessing fit with clinical practice. The thesis is the first public domain wide-ranging analysis of business trends in the production, manufacturing and supply segments of the RM industry. It analyses the clinical potential of the domain as well as the translational and commercial challenges facing the industry. The industry is at a turning point as big pharmaceutical companies engage with RM in order to explore technologies as potential therapeutics and discovery tools. This unlocks the industry by confirming an exit path for RM based small- and medium-sized enterprises. Translation has come to be recognised as a core issue in the overall space and translation of regenerative therapies into the clinic is presently challenging, high-risk and expensive. This research addresses the question what are the mechanisms required to enable translation of emerging scientific knowledge into commercially viable clinical RM products? These mechanisms are particularly important as their creation involves and requires major investment decisions, which can determine the success or failure of RM developments and indeed of the companies concerned. The lack of well-established business models and the complexity of the domain suggested a conceptual approach drawing upon relevant literature from product and process development, applied business and revenue models, technological evolution and capital market ingenuity. The research was carried out in two phases. The first phase was concerned with identification of key challenges and mapping the overall industry emergence including emergence of related regulations to provide a context and framework for understanding the domain. Based on the emergence mapping a timeline of key parallel factors was identified, and their inherent connections explored to identify transforming events affecting and influencing multiple factors on the journey to clinical success within a business environment. This creates the reference model. The second phase was concerned with manufacturing a stem cell based therapeutic and applying health economic principles to determine available headroom for investment, cost of goods and return on investment, taking hearing disorders as a case exemplar, and exploring the behaviour of the net present value curve to identify key parameters affecting the economic positioning of this novel regime. A key output of the research is the investment readiness reference model. It integrates key RM business issues against reducing uncertainty and increasing value. The model argues that the complex nature of RM products means that the issues affecting industry emergence and development go well beyond the primarily scientific and technological concerns on which much current research focuses. The performance of RM firms ultimately hinges upon the successful clinical application of their developed products, the key step for creating and realising value, and their ability to deal with the fundamental business issues specific to the area. The framework deals with these business issues, which are investment & technology readiness, business models, organisational challenges, public policy and industry emergence. This thesis explores ideas that may bridge the chasm between the promise and reality of RM i.e. mechanisms to enable late stage translation of RM products. It links technological capability and business models for firms in the domain. Furthermore, it offers a unique perspective on the nature and characteristics of investment readiness and financial assessment, specifically identifying key parameters affecting economic positioning. The key contributions are therefore: New insights into the key challenges involved in realising the commercial potential of cell based therapeutics. Technology road mapping to link fundamental enabling technological capability for developing RM products with robust business plans integrating strategy, technology development and the regulatory and reimbursement framework. A generic investment readiness reference model generated from the enabling technology, value and supply chain structures to identify key indicators and characteristics of industry readiness. A novel experimental programme demonstrating expansion, maintenance and differentiation of human embryonic stem cells by manual and automated methods. New insights into economic positioning by mapping net present value, and economic analysis by estimating available headroom, cost of goods and return on investment for a putative hearing therapeutic.
32
van, Nobelen Robert. "Coding for the Rayleigh fading channel." Thesis, University of Canterbury. Electrical and Electronic Engineering, 1996. http://hdl.handle.net/10092/6060.
Abstract:
The problem of effective coding for the Rayleigh fading channel is addressed. A signal transmitted over the Rayleigh fading channel experiences quasi-periodic deep fades in the signal amplitude, and random phase shifts. The fades in signal amplitude are the cause of error events and limit the bit error rate of an uncoded system to about 10-4 at a signal-to-noise ratio of 30 dB. For applications where a lower error rate is desired, more sophisticated methods of transmission and detection are required. We present an extensive generalised analysis of the probability of error of maximum likelihood sequence estimation techniques for the Rayleigh fading channel
This analysis provides the criteria for good code design for the Rayleigh fading channel and we extend the recently developed area of geometrically uniform (GU) codes for the AWGN channel, to the Rayleigh fading channel, and present the results of searches for good GU trellis codes.
The concept of geometric uniformity is extended to set of points to form geometrically uniform partitions of signal sets. The GU partitions readily allow powerful multi-level codes to be defined with good distance properties. Multi-level codes have the advantage of outperforming trellis codes in terms of decoding complexity at the cost of greater decoding delay. Good multi-level codes over GU partitions are presented and compared with similarly performing trellis codes.
Finally a system is presented which combines the techniques of multiple symbol differential detection (MSDD) with multi-level coding to obtain a good probability of error performance without assuming coherent detection, or ideal channel state information.
33
Gokce, Mersin. "Coupled stability analysis of close proximity ship towing." Thesis, Monterey California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/6060.
Abstract:
Approved for public release, distribution is unlimitedThe scope of this thesis is to study the stability of two ships in close proximity towing. Unlike previous studies in the past, the lateral dynamics of both ships are included in the formulation. The equations of motion of the system consist of the sway and yaw motions of the two ships and a control law for the leading ship. An eigenvalue stability analysis of the coupled system confirms the results that are obtained through numerical simulations. It is shown that it is possible for the system to be unstable even through the classical criteria for the towing stability are satisfied. A series of parametric studies is conducted in order to analyze the sensitivity of the system for different towline lengths, tension, and control time constant.
34
Laporte, Marie Noël. "Traduction de fugues-poèmes : une approche intersémiotique." Mémoire, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6060.
Abstract:
Résumé : Musicienne et traductrice de formation et de métier, je présente ici des traductions de poèmes contemporains qui s’annoncent, par leur titre ou leur forme, comme des fugues. Comme hypothèse de départ, je pose la possibilité du transfert des éléments de fugue musicale à ceux de la fugue littéraire. Ma démarche se décline en deux parties. Dans un premier temps, j’analyse les poèmes en suivant pas à pas la méthode de critique des traductions littéraires d’Antoine Berman. La méthode est adaptée à la traduction intersémiotique et rend compte des éléments de fugue contenus dans chacun des poèmes à l’étude. Dans un second temps, une fois le « projet de traduction » bien établi, je propose une traduction française des fugues-poèmes. Dans l’esprit de ce que Barbara Folkart nomme des « traductions d’auteur », dans le rendu proposé, je m’éloigne des approches dénotatives, tentant de réactualiser en français la démarche compositionnelle des poètes. Que retiendront les poètes pour leur projet de fugue-poème? Une confusion est-elle possible avec d’autres formes répétitives, comme le canon, le thème et variations, le ground, la chaconne, la passacaille, voire des formes de musique minimaliste? Malgré les appréhensions d’un certain nombre de critiques, qui taxent de « vaines » toute expérience intersémiotique ou toute tentative pour en démontrer les correspondances, on trouve quelques exemples probants de fugues littéraires. Bien entendu, la musique ne peut se traduire directement en mots. En s’attardant aux phénomènes perceptuels et créatifs, on accède à un degré correct de pertinence.
Je me suis donné pour méthodologie le modèle de critique des traductions littéraires d’Antoine Berman, dont j’ai fait l’ossature des chapitres et auquel j’ai greffé des grilles d’analyse paradigmatique et rythmique. J’ai aussi eu recours à un pense-bête des principaux éléments fugaux (constituants de la fugue musicale, définitions de « fugue » dans la langue courante et critères psychiatriques de la « fugue dissociative »). Un questionnaire maison a été le point de départ de mon travail de collaboration avec les poètes. Dans le cas de Paul Celan (1920-1970), j’ai utilisé le même questionnaire, que j’ai rempli au gré de l’analyse et du dépouillement d’autres recherches.
J’explore dans les six premiers chapitres les poèmes « Todesfuge » (1945) de Paul Celan, « Night Thoughts on Clauzewitz’s On War » (1986) d’E. D. Blodgett, « Lives of the Great Composers » (1983) de Dana Gioia, « Domestic Fugues » (2009) de Richard Newman, « Art of Fugue » (2011) de Jan Zwicky » et « Arugula fugues » (2001) d’Adeena Karasick. Dans la conclusion, je discute les résultats de recherche, les choix méthodologiques et le processus de traduction. Un tableau-synthèse des correspondances fugales est aussi présenté et commenté. Le chapitre intitulé « Stretto » vient élargir le corpus des fugues-poèmes analysées et traduites. J’y présente les fugues-poèmes suivantes : « Fugue » et « Round » de Weldon Kees, « Fugue in Cold and Rain » et « Little Fugue of Love and Death » de Richard Newman, « The Praying Mantis » d’Annie Charlotte Dalton Armitage, « The Ballad of the Pink-Brown Fence » de Milton Acorn, « The Children are Laughing » de Gwendolyn MacEwen, « And the Season Advances » d’Herménégilde Chiasson (dans une traduction de Jo-Anne Elder et de Fred Cogswell), « Fugue » de Robyn Sarah, « Fugue » du Kaddish d’Allen Ginsberg, « Fugue » de Neville Dawes, « Seaside Canon » de Julia Galef et « Stretto » de Don MacKay. // Abstract : As a professional musician and translator, I am presenting my translations of contemporary poems that are, either through their titles or their forms, fugue-poems. It is my hypothesis that elements present in a musical fugue can be transferred to a literary fugue. There are two parts to my research. First, I analyze the poems in strict accordance with Antoine Berman’s critical method for literary translation. I adapted the method in order to work with inter-semiotic translation, as well as the fugal elements contained in each of the poems studied. Next, with the “translation project” well established, I propose a French translation of the fugue-poems. Based on Barbara Folkart’s notion of “writerly translations,” I will attempt to capture the essence of the poems and recreate true works of literary art in French, rather than using purely denotative translation methods. Which elements do poets employ in their fugue-poems? Is there a possibility of confusing fugal elements with other repetitive forms, such as a canon, a theme and variations, a ground bass, a chaconne, a passacaglia or even certain forms of minimalist music? Despite the apprehension of some critics, who believe that inter-semiotic work or even the attempt to reveal any form of relationship is in vain, there are a number of clear examples of literary fugues. Naturally, music cannot translate directly into words. However, a study of the perceptual and creative phenomena allows us to make the connection. My research methodology is based on Antoine Berman’s model meant for critics of literary translations, which provides the backbone for the chapters in this presentation, and to which I have added a paradigmatic and rhythmic analysis grid. I also used a memory aid of the principal fugal elements (components of a musical fugue, definitions of a “fugue” in common usage, and the characteristics of the psychiatric disorder referred to as “dissociative fugue”). I designed a questionnaire, which I used as the basis for my collaboration with the poets. In the case of Paul Celan (1920-1970), I used the same questionnaire, which I filled out based on my analysis of his work, as well as analyses put forth by other researchers. In the first six chapters, I explore the following poems: “Todesfuge” (1945) by Paul Celan, “Night Thoughts on Clauzewitz’s On War” (1986) by E. D. Blodgett, “Lives of the Great Composers” (1983) by Dana Gioia, “Domestic Fugues” (2009) by Richard Newman, “Art of Fugue” (2011) by Jan Zwicky and “Arugula fugues” (2001) by Adeena Karasick. In the conclusion, I discuss the research results, the methodological choices and the translation process. I have also included a summary table (with comments) of the corresponding fugal elements. The chapter entitled “Stretto” concludes the corpus of analyzed and translated fugue-poems. It includes: “Fugue ” and “Round” by Weldon Kees, “Fugue in Cold and Rain” and “Little Fugue of Love and Death” by Richard Newman, “The Praying Mantis” by Annie Charlotte Dalton Armitage, “The Ballad of the Pink- Brown Fence” by Milton Acorn, “The Children are Laughing” by Gwendolyn MacEwen, “And the Season Advances” by Herménégilde Chiasson (translation by Jo-Anne Elder and Fred Cogswell), “Fugue” by Robyn Sarah, “Fugue” from Kaddish by Allen Ginsberg, “Fugue” by Neville Dawes, “Seaside Canon” by Julia Galef and “Stretto” by Don MacKay.
35
Galvão, Lurdes. "Avaliação nutricional do feno de lameiros do nordeste de Portugal. Possibilidades da utilização de métodos laboratoriais." Master's thesis, Instituto Agronómico e Mediterranico de Zaragoza, 1994. http://hdl.handle.net/10198/6060.
Abstract:
Na revisão bibliográfica, efectuou-se uma pequena descrição do Nordeste de
Portugal, nomeadamente Bragança e Vinhais, no que respeita à geografia, clima, solo,
efectivo ruminante e composição florística dos lameiros da região. Os ruminantes são a
componente principal do sistema de produção da região devido aos condicionalismos do
solo, clima e povoamento, favoráveis aos pastos naturais (lameiros). Estes cobrem uma
grande superfície e são utilizados para pastoreio directo pelos animais durante uma pane do
ano e vedados ao pasto, durante Março/Abril ou Maio/Junho, dependendo do local, para
obter maior produção de erva para fenar. A composição florística dos lameiros e muito
complexa e variável de local para local dentro da regiãoEscola Superior Agrária de Bragança e Universidade de Trás os Montes e Alto Douro
36
Echenique, Yupanqui Mario Efrain. "Relación entre ingesta de proteínas de alto valor biológico y hierro dietario con niveles de hemoglobina en mujeres gestantes que asisten a consulta nutricional, Hospital EsSalud Chincha, julio a setiembre de 2016." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/6060.
Abstract:
Determina la relación que existe entre la ingesta de proteínas de alto valor biológico y hierro dietario con niveles de hemoglobina en mujeres gestantes que se atendieron por consulta externa en el Servicio de Nutrición del Hospital de EsSalud Chincha. Es un estudio cuantitativo, diseño descriptivo, correlacional, transversal. Utiliza una muestra de 114 mujeres gestantes. La técnica de recojo de información es la entrevista y aplica una encuesta de frecuencia de consumo de alimentos. Emplea el análisis de regresión lineal múltiple para el tratamiento estadístico de los datos. Encuentra un 33% de gestantes anémicas, un 44% y 54% de gestantes con ingesta deficiente de proteínas de alto valor biológico y hierro dietario respectivamente. Existe correlación estadísticamente significativa entre la ingesta de proteínas de alto valor biológico y hierro dietario con los niveles de hemoglobina (r>0,80; p<0,001). La ingesta de proteínas de alto valor biológico y hierro dietario influyen directamente sobre los niveles de hemoglobina en mujeres gestantes.Trabajo académico
37
Nackerdien, Moegammad Faeez. "A panel data analysis on the formal-informal sector linkages in South Africa." University of the Western Cape, 2017. http://hdl.handle.net/11394/6060.
Abstract:
Magister Commercii - MCom (Economics)There are few studies on linkages between the formal and informal sectors in South Africa. This study explores the types of linkages between the informal and formal sectors with empirical research concentrating on labour churning (movements between the informal and formal sectors). Using National Income Dynamics Study (NIDS 2008-2014) data from four waves, individuals are classified into labour market statuses based on the Heintz & Posel (2008) methodology. This study conducts labour market transitional matrices and finds formal employment to provide the most stability in terms of employment. The main focus is on the following three groups of employed: working in the formal sector in all four waves; working in the informal sector in all four waves; moving between the formal and informal sectors across all four waves. For those always working in the formal sector, they are predominantly females and Africans. Those who always work in the formal sector are most educated, while those always working in the informal sector are associated with low educational attainment. The descriptive statistics are followed by econometric analysis: in terms of attaining employment, being male and a higher educational attainment significantly increase the probability of finding employment. In terms of sustaining work, the same two covariates significantly increase the probability of sustaining work. Being the head of household is also a key covariate in significantly increasing the probability in maintaining and sustaining employment. In terms of transitioning to formal employment, being male, an increase in education and living with a partner (married or unmarried) significantly increase the probability of moving to formal sector employment. In addition, multinomial logistic regressions are conducted, and the results indicate that being a male significantly increases the probability of working in the formal sector for all four waves. Africans are also significantly more likely to be employed informally for all four waves and an increase in the years of education significantly increases the probability of being formally employed for all four waves. The household-level variables reveal that being the head household significantly increases the probability of being employed (especially formally employed for all four waves) while having children has a negative impact on being employed for all four waves.
38
Ceresér, Keila Maria Mendes. "Avaliação dos níveis de proteína ácida fibrilar glial em tecidos cerebrais de ratos submetidos a choque eletroconvulsivo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/6060.
39
Paulo, Margarida do Rosario Domingos. "Fertility, sexuality and HIV/Aids prevention campaigns in Mafalala barrio, Maputo, Mozambique." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6060.
Abstract:
Includes bibliographical references (leaves 74-87).This paper attempts to understand perceptions of fertility and sexuality in relation to HIV/Aids prevention in Mafalala barrio, Maputo, Mozambique. The work explores ways in which people create or re-create meanings for fertility in order to fulfil kinship expectations. The notion of individual choice highlighted in the condom campaigns is contrasted with people's ideas about 'protection'. This suggests that socio-cultural factors should be taken into account when developing HIV/Aids prevention programs. The study concludes with a discussion of some lessons for the HIV/Aids educational programs in Mafalala and other areas similar to the barrio.
40
Kia, Arash. "Modeling the effects of many valley electron scattering on the current-voltage characteristics of resonant tunneling diodes /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/6060.
41
He, Jiexuan. "Effects of spin current in ferromagnets." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/6060.
Abstract:
Thesis (Ph. D.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 4, 2009) Vita. Includes bibliographical references.
42
Sweat, Eric J. "Investigation of Structural Capacity of Geogrid-Reinforced Aggregate Base Materials in Flexible Pavements." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6060.
Abstract:
The installation of geogrid as a means of extending the service life of a roadway or reducing the required base course thickness of a pavement structure has become increasingly popular. The realization of these benefits depends largely on the degree to which the geogrid reinforcement leads to an increase in the stiffness of the aggregate base course layer. The objective of this research was to investigate the structural capacity of geogrid-reinforced aggregate base materials in flexible pavements through full-scale testing. The scope involved field testing at two sites in northern Utah that each included five different geogrid-reinforced sections and five accompanying unreinforced control sections. Five different geogrid types were utilized to ensure that the experimentation was representative of the geogrid products available in the industry at the time of the study. At each of the two field sites, 10 test sections were established, and several field tests were conducted during and following construction of the two pavements to characterize the in-situ structural properties of the subgrade, base, and hot mix asphalt layers of each geogrid-reinforced and unreinforced test section. The procedures involved nuclear density gauge, soil stiffness gauge, Clegg impact soil tester, dynamic cone penetrometer (DCP), portable falling-weight deflectometer, and falling-weight deflectometer testing of each test section. Samples of the subgrade and base materials were also obtained from both field sites for laboratory testing, which included dry and washed sieve analyses, Atterberg limits testing, and material classification. An analysis of covariance (ANOCOVA) was conducted on the results of each field test to determine if the structural capacity of the geogrid-reinforced sections was different than that of the accompanying unreinforced control sections.Among the 24 ANOCOVA models developed for the two field sites, only four indicated that geogrid presence was statistically significant. Of these four models, three indicated that the presence of geogrid reinforcement led to higher values of the given measurement of structural capacity compared to the unreinforced condition; however, in none of the cases was the difference practically important as defined in this research and would therefore not result in a different input in the pavement design process. Notably, in all three of these models, the same testing procedure, namely the DCP, was used for the testing. A measurable increase in the structural capacity of the reinforced layer may not be immediately observable using standard pavement testing procedures. Further field research is recommended to investigate the duration of the required conditioning period and also the extent of the zone of influence of geogrid reinforcement in aggregate base courses.
43
BonDurant, Lucas Donald. "Regulation of glucose homeostasis by FGF21." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6060.
Abstract:
Fibroblast Growth Factor 21 (FGF21) is an endocrine hormone derived from the liver that exerts pleiotropic effects on the body to maintain overall metabolic homeostasis. During the past decade, there has been an enormous effort to understand the physiological roles of FGF21 in regulating metabolism and to identify the mechanism for its potent pharmacological effects to reverse diabetes and obesity. Through both human and rodent studies, it is now evident that FGF21 is dynamically regulated by nutrient sensing and consequently functions as a critical regulator of nutrient homeostasis. In addition, recent studies with new genetic and molecular tools have provided critical insight into the actions of this exciting endocrine factor. Dissection of these FGF21-regulated pathways has tremendous potential for new targeted therapies to treat metabolic disease. The goals of this thesis are 1) to identify FGF21’s physiological role as a carbohydrate-regulated signal of macronutrient-specific satiety and 2) to determine the mechanism and tissues responsible for mediating the pharmacological effects of FGF21.
To address the first goal, we used different FGF21 genetic knockout mouse models to determine if loss of FGF21 would affect macronutrient preference. We found that loss of FGF21 led to an increase in simple sugar intake whereas this had no effect on other macronutrients such as lipid or protein. To further characterize the relationship between carbohydrates and FGF21, in vitro and in vivo techniques revealed that FGF21 transcription in the liver increased in response to carbohydrate intake and this was dependent on the presence of a transcription factor activated by carbohydrates, ChREBP. We next addressed whether or not increased FGF21 levels would affect preference for simple sugars. We found that in response to increased circulating levels of FGF21, either through genetic overexpression or pharmacological administration, FGF21 would lead to a significant decrease in caloric and non-caloric sweeteners. Finally, we were able to determine that FGF21 was signaling to the hypothalamus to mediate this suppression of simple sugar intake through region specific knockout of the co-receptor beta-klotho.
To address the pharmacological actions of FGF21, we generated an adipose-specific KLB KO mouse using mice that express Cre-recombinase under the adiponectin promoter. These mice lack the co-receptor for FGF21 in adipose tissue and are a more reliable adipose knockout model than previous studies that have used aP2-Cre mice. We were able to determine that the acute glucose lowering effects of FGF21 are mediated through direct signaling to adipose tissue and that FGF21 enhances insulin sensitivity by increasing glucose uptake in brown adipose tissue. However, FGF21 mediates its chronic effects, including lowering body weight and triglycerides, by signaling to some other non-adipose tissue. Overall our work has shown that FGF21 can significantly regulate glucose metabolism through multiple mechanisms.
44
Richey, David J. "Fault Seal Analysis for CO2 Storage: Fault Zone Architecture, Fault Permeability, and Fluid Migration Pathways in Exposed Analogs in Southeastern Utah." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/6060.
Abstract:
Geologic storage of anthropogenic carbon dioxide (CO2) by injection into underground porous sandstone reservoirs has been proposed as a method for the reduction of anthropogenic greenhouse gas emissions. Upwards migration and leakage of injected fluids along natural fault and fracture networks is a key risk factor for potential injection locations. We examine exposed natural analogs to evaluate the impacts of faulting and fracturing on reservoir and top-seal pairs and to evaluate evidence for paleomigration of fluids along the fault zone.
We examine the Iron Wash fault, a 25-km long normal fault which cuts Jurassic sedimentary rocks and has throws that range from 20-120 m, to examine how a fault may affect seal integrity. Field mapping, kinematic analysis, petrographic analysis, characterization of the fault zone facies and fault architecture, analysis of altered and mineralized rocks in and around the fault zone, and modeling of fault seal capacity was conducted to provide an understanding of the Iron Wash fault zone. Field data and observations were combined with well log and borehole data to produce three types of models for the Iron Wash fault: 1) geometric model of the fault in the subsurface, 2) predictive models of fault zone behavior and fault seal analysis, and 3) predictive geomechanical models of the response of the fault zone to an imposed stress field and increasing the effective stress on the fault.
We conclude that the Iron Wash fault zone has low sealing capacity and will likely not behave as a seal for fluids against the fault zone due primarily to modest throw on the fault and high frequency of fractures associated with the fault zone. Analysis of fluid alteration and mineralization around the fault zone indicates that the fault zone was conduit for paleo-fluids. We conclude that the fault is not likely to develop a sealing membrane and therefore will most likely fail as a seal to fluids moving through the reservoirs modeled here. Modeling results indicate that a reduction in the effective normal stress on fault surfaces may induce failure of faults resulting in earthquakes or increased hydraulic conductivity of fractures.
45
Masawi, Francisca. "Young Women's Perceptions of Factors Influencing Eating Disorders." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/6060.
Abstract:
Eating disorders (EDs) cause irreversible physical damage, including organ failure and death. Although EDs receive considerable attention, the number of affected young women who seek help remains low. The purpose of this phenomenological study was to understand the sociocultural and socioenvironmental factors influencing ED development from the perspective of young women, and to explore why the rate of EDs continues to rise in this population. The sociocultural model served as a guide for the study. Ten young women 18-24 years old from Southwest Ohio participated in in-depth, semi structured, face-to-face interviews. Data coding and analysis revealed recurring themes, with findings indicating that family relationships and social media were major factors influencing young women's perceptions of personal image and attractiveness. Participants described that social media's negative portrayal of beauty leads to internalization of the thin-ideal, leading to body dissatisfaction, with subsequent negative dieting behaviors that increase the risk for eating disorder development. Family relationships were described as the main source of positive support to neutralize these external negative forces by creating environments where these young women are accepted. A combination of media, availability of fast food, and society's portrayal of beauty, had significant influences on ED development by creating "constant internal struggles" on body image, good food choices and acceptance in society. The study impacts social change by adding new information for public health program developers and policy makers that may be used to introduce ED programs in local schools that will empower these young women to seek help without fear of stigma or alienation.
46
Tyutyunyk-Massey, Liliya. "MODULATION OF AUTOPHAGY AND SENESCENCE TO ENHANCE THE RESPONSE TO THERAPY IN TRIPLE NEGATIVE BREAST CANCER." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6060.
Abstract:
Abstract
Although great strides have been made over the decades in development and optimization of anti-cancer therapies, even highly effective drugs often fail to completely eliminate tumors. Residual tumor cells can enter into a state of dormancy for prolonged periods of time but eventually are able to regain proliferative capacity and reemerge as chemotherapy-resistant disease. Because recurrent disease is a leading contributor to patient’s mortality, it is paramount to identify strategies for effectively destroying residual tumor cells.
Cytotoxic drugs and ionizing radiation are used as standard therapies in a variety of cancers. These modalities induce apoptosis, autophagy and senescence. Senescence is a state of prolonged growth arrest, which cells are able to eventually escape regaining proliferative capacity.
Autophagy is generally considered to be a protective mechanism; however, it can take non-protective or even cytotoxic form in response to anti-cancer treatments. Furthermore, chemotherapy or radiation induced autophagy was shown to be a contributor to the immune response against tumor cells.
Using a model of Triple Negative Breast Cancer, we were able to show increased immunosurveillance of tumor cells after enhanced autophagy was achieved by combining epigenetic remodeling with chemotherapy.
Alternatively, we were able to achieved effective clearance of tumor cells induced into senescence by chemotherapy or radiation by the senolytic drug ABT-263 (Navitoclax). In summary, autophagy and senescence alone or in concert, can be induced by conventional anti-tumor modalities. Those processes can be modulated independently to achieve clearance of residual tumor cells following anti-cancer therapies.
47
Squarcia, Catia <1989>. "“Dealing with the ecological crisis: a case for cultural approaches”." Master's Degree Thesis, Università Ca' Foscari Venezia, 2015. http://hdl.handle.net/10579/6060.
Abstract:
The environmental crisis we are currently experiencing is still mostly approached through technocratic strategies. Technical approaches have, however, deep limits in promoting long-term results. The ecological crisis is instead a cultural problem, to which we need to react with cultural approaches. It will be, in the next decades, essential to involve the Global Citizenship in pursuing a radical change in lifestyles and mentality about the role of the humankind on the planet and its relationship with the nature. In order to achieve awareness and responsible attitudes towards the environment, beyond technical tools, we urgently need education to sustainable patterns and a new transdisciplinary orientation in the knowledge development. Education to sustainability will depend both on institutional pathways and on grassroots and civil society movements that, proposing alternative lifestyles, informally educate the population to different and more sustainable worldviews than the western consumeristic one. Beside the involvement of the population on a global scale, dealing with such global problem requires an approach in the research that promotes cooperation and integration among the fields of studies and the society practitioners, beyond the traditional sectorization and division among the sciences, and without which is not possible to develop an integrated and holistic understanding of the current situation.
48
Тихенко, C. В. "Применение эколого-экономических показателей в управлении и планировании развития топливно-энергетического комплекса." Thesis, Суми, 1993. http://essuir.sumdu.edu.ua/handle/123456789/60660.
Abstract:
Применение эколого-экономических показателей в управлении и планировании развития топливно-энергетического комплексаApplication of environmental and economic indicators in the management and planning of the development of the fuel and energy complex
49
Щербак, В. Д. "Цілі та пріоритети стратегії інтеграції банківської системи України у світовий фінансовий простір." Thesis, Українська академія банківської справи Національного банку України, 2004. http://essuir.sumdu.edu.ua/handle/123456789/60260.
Abstract:
Одним із найважливіших чинників розвитку людської цивілізації,
безумовно, виявилася інтеграція. Термін “інтеграція” походить з латині, де
integratio означає з’єднання окремих частин у загальне, ціле, єдине. Одним із
видів інтеграції є інтеграція банківської системи України у світовий фінансовий
простір. Вона – найвищий ступінь розвитку міжнародних економічних
відносин.
50
Маркіна, І. А., and Л. П. Поставна. "Організація ризик-менеджменту в банківській сфері." Thesis, Українська академія банківської справи Національного банку України, 2004. http://essuir.sumdu.edu.ua/handle/123456789/60560.
Abstract:
Практика здійснення економічної діяльності на сучасному етапі дозволяє
стверджувати, що ризик-менеджмент - одна з наук, яка з усього спектра
напрямків фінансового менеджменту найбільш динамічно розвивається.
Чисельність і масштаби ризиків на фінансових ринках у світі постійно
зростають, збільшуючи значущість ризик-менеджменту для бізнесу.
Особливість вітчизняного фінансового ринку, що характеризується високим
рівнем політичного, законодавчого, правового ризику, значними коливаннями
цін, кризовими явищами, також переконує в необхідності управління ризиками.