Uma grande variedade de modelos é utilizada para estimar a pressão de ruptura de dutos contendo defeitos de corrosão. O presente trabalho tem como objetivo estudar a precisão dos modelos mais comuns e avaliar a pressão de ruptura de dutos submetidos à corrosão. Os modelos avaliados são: ASME B31G, ASME B31G modificado, DNV RP F101 e PCORRC. O estudo é baseado em mais de 400 resultados de ensaios de ruptura em dutos corroídos, todos coletados da literatura. A base de dados contem defeitos de corrosão reais e artificiais. Uma análise estatística foi realizada para a variável erro de modelo. Uma análise de regressão não-linear foi realizada para investigar os efeitos da variável erro de modelo, das variáveis mais relevantes, como profundidade e comprimento do defeito, e tensão de ruptura do aço. Uma análise de confiabilidade foi realizada a partir das estatísticas obtidas da variável erro de modelo, sendo estimado o índice de confiabilidade e a probabilidade de falha do duto com defeitos de corrosão, através do método iterativo de primeira ordem, denominado FORM (First Order Reliability Method). Nesta análise avaliou-se a evolução da probabilidade de falha com o aumento da profundidade do defeito, bem como foram identificadas as variáveis aleatórias mais importantes na falha do duto. O estudo pode ajudar aos operadores a eleger qual modelo utilizar em análises de risco, proporcionando mais segurança às operações dutoviárias. / A variety of models exist to estimate burst pressures of pipelines containing corrosion defects. The objective of this work is to study the accuracy of some of the most popular empirical burst pressure models. The study addresses the models: ASME B31G, ASME B31G Modified, DNV RP-F101 and PCORRC. The investigation is based on over 400 burst test results, all collected from the literature, containing both real and artificial corrosion defects. A statistical analysis is performed for assessing the accuracy of semi-empirical models by using a model error variable. A non-linear regression analysis is performed to identify the influence, on model errors, of the most relevant variables, such as defect depth and length and steels rupture tension. A reliability analysis was carried out, using model error statistics developed herein, in order to evaluate reliability index and probability of failure of pipelines containing corrosion defects, through the iterative first order reliability method, or FORM - First Order Reliability Method. The evolution of failure probabilities, with increasing defect depth, was investigated. The most relevant random variables were identified. The study can help operators choose a proper empirical model to use in their risk analysis, leading to greater safety in pipeline operations.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-08-03T12:16:33Z No. of bitstreams: 1 gabriellafreitasferreira.pdf: 1111733 bytes, checksum: 4b8a7e3965e36b834dcb1890165ad008 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-08-03T12:21:08Z (GMT) No. of bitstreams: 1 gabriellafreitasferreira.pdf: 1111733 bytes, checksum: 4b8a7e3965e36b834dcb1890165ad008 (MD5) / Made available in DSpace on 2018-08-03T12:21:08Z (GMT). No. of bitstreams: 1 gabriellafreitasferreira.pdf: 1111733 bytes, checksum: 4b8a7e3965e36b834dcb1890165ad008 (MD5) Previous issue date: 2015-07-03 / PROQUALI (UFJF) / Embora os principais mecanismos de ação do fluconazol, itraconazol e anfotericina B estejam relacionados ao egosterol, é possível que essas drogas tenham outros efeitos nas células fúngicas. Além dos mais, a heterorresistência é considerada um mecanismo de adaptação frente a um estresse induzido por concentrações crescentes de antifúngicos no ambiente. Sendo o itraconazol um dos azólicos usados no tratamento da criptococose, o objetivo desse estudo foi avaliar a influência do estresse oxidativo e nitrosativo gerado pelos antifúngicos em células de C. gattii e sua influência no surgimento de clones heterorresistentes. Foram estudados distintos parâmetros para avaliar os estresses oxidativo e nitrosativo induzidos pelo fluconazol, itraconazol e anfotericina B em C. gattii. Já os efeitos da heterorresistência ao itraconazol foram estudados por meio de ensaios in vitro e em modelo murino. O itraconazol simultaneamente reduziu o conteúdo de ergosterol das células de C. gattii e induziu a produção de espécies reativas de oxigênio no início do tratamento, o que levou ao aumento da atividade das enzimas peroxidase e superoxidodismutase. O mesmo não aconteceu com o fluconazol. Já a anfotericina B promoveu grande estresse oxidativo e nitrosativo nas células de C. gattii, o que levou a uma elevada peroxidação lipídica e ineficiente ativação do sistema antioxidante celular. A heterorresistência ao itraconazol foi intrínseca para todas as linhagens testaddas, alterou parâmetros farmacodinâmicos, diminuiu o diâmetro celular e o tamanho da cápsula e ativação do sistema antioxidante celular. Observou-se uma correlação positiva entre a razão superfície/volume e o nível de heterorresistência ao itraconazol. Além do mais, a heterorresistência levou a maior internalização das células criptocócicas pelos macrófagos, mas também a uma maior proliferação dentro dessa célula fagocítica, o que culminou com o aumento da virulência dos clones heterorresistentes e alta carga fúngica nos pulmões e cérebro dos camundongos. Diante desses resultados, concluiu-se que o estresse oxidativo possuiu um importante papel no mecanismo de ação do itraconazol e pode ser um dos mecanismos que levam a heterorresistência e o aumento da virulência das células de C. gattii. / Although the most accepted mechanisms of action of amphotericin B and azoles are related to ergosterol, it is possible that these drugs have other effects on the fungal cell. Moreover, heteroresistance is an adaptive mechanism developed by the microorganism to counteract the stress of increasing drug concentration in the environment. Since itraconazole is used in the therapy of cryptococcosis, the aim of this study was to evaluate the role of endogenous reactive oxygen species (ROS) and peroxynitrite produced by azoles and amphotericin B in the fungus C. gattii and its influence on emergence of heteroresistante clones to itraconazole. We studied distinct parameters to evaluate the effect of oxidative and nitrosative stresses induced by fluconazole, itraconazole and amphotericin B in C. gattii cells. The effects of the heteroresistance to itraconazole were studied by performing tests in vitro and in a murine model. Itraconazole reduces the level of ergosterol and led to ROS production in C. gattii cells in the early stages of the treatment, enhancing the antioxidant activity. The same did not happen with fluconazole. Amphotericin B caused lipid peroxidation in C. gattii cells through a greatly enhanced production of oxidative and nitrosative radicals with increased lipid peroxidation and inefficient ativaction of antioxidant cellular system. Heteroresistance to itraconazole was intrinsic in all strains tested and changed pharmacodynamics parameters, diminished cell and capsule sizes, reduced ergosterol content and enhanced the antioxidant system of heteroresistant clones. Indeed, heteroresistance to itraconazole led to the increased internalization of cryptococcal cells by macrophages, but also to a prominent proliferation inside these phagocytic cells, culminating in the higher virulence of heteroresistant clones. Based on these results, we conclude that oxidative bursts play an important role in the antifungal activity of itraconazole and may be one of the mechanisms that lead to heteroresistance and the increased virulence of C. gattii.

This thesis presents the idea of providing QoS in All-Optical Networks. The thesis investigates available mechanisms of differentiation services in Optical Packet/Burst Networks. It provides an overview of current state-of-art in this domain together with literature research in order to evaluate and present qualitative and quantitative comparison of three chosen algorithms which are suitable for providing QoS in OPS/OBS networks. The thesis includes also research in teletraffic modeling of Optical Networks.

No description available.

Field and laboratory experiments were conducted to elucidate various factors influencing the temperature-dependent larval eclosion of winter moth, Operophtera brumata L, in New England. We found no difference in duration of the embryonic stage of eggs reared from larvae collected in Massachusetts (MA) and on Vancouver Island, British Columbia (BC), where winter temperatures are rarely below freezing. The number of growing degree days (GDD) required for larval eclosion declined with the number of days chilled in the laboratory and number of days below freezing in the field, confirming the findings of previous studies. Thus, eggs hatched with fewer GDD, when the spring came later than usual. Date of oviposition had no effect on date of hatch. Eggs laid by naturally occurring (feral) females hatched sooner with lower GDD than eggs from laboratory-reared females from MA and BC held on the same trees over the winter. South-facing eggs on the stems of trees hatched on average 1.6 days sooner than north-facing eggs. Growing degree days calculated from bi-hourly measures of temperature were 15% greater than GDD estimates based on the average of daily maximum and minimum temperatures, as used by many GDD estimates made for online sources. Over two years, the mean GDD in ⁰C for hatch of feral eggs based on bihourly temperature measurements, a 1 Jan start date and a 3.9⁰C developmental threshold was 176.53 ± 6.35SE

The present study examined operant extinction in a controlled setting using a human operant paradigm. Participants watched a preferred video. During the video, either the video or audio portion of the video was selectively removed, on average every 15 s. Participants could restore the video by pressing a force transducer. In one group, relatively low forces were required (250 g) and in the other relatively high forces were required (750 g). At the 20th and 30th minute during the session, the video or audio was removed but the participants could not restore the component for 30 s. The results showed that responding during the probe increased relative to 30-s periods prior and following the probe, characteristic of an extinction burst. The results also showed that overall we saw increases in force under high force conditions during extinction when presses no longer produced sound or video, and force changed little during the low force conditions. We conclude that extinction bursts are a robust phenomenon that can be demonstrated in humans. Additionally, the topographies, i.e. force, established during baseline and the modality of the consequence appear to be two variables determining the short-term course of extinction.

The initial part of my work is dedicated to overall introduction into the transmission systems and its categories. Further the work is focused on dividing of security codes which are used for transmission systems. In the next chapter is analyzed the problems of error origin, mathematical transcription of errors, categorizing of errors which can generate during transmission. The following chapter deals with description of convolutional codes describing security against errors, principle of serial consecution interpretation on parallastic consecution and visa versa. Here is outlined problems of convolutional codes input. In the next part are mentioned three convolution codes which are used for security against burst errors. In the next chapter is mentioned problems of message interleaving and description of used methods, how they originate and detailed description, how the errors are eliminated with the help of long segment interleaving. In the next chapter are described techniques which are used for clustered errors suppression. The last chapter is dedicated to the practical part of my thesis. There are detail descriptions and simulation techniques how the security of non-secure section is developed, transmission on line, burst errors induction on transmitted secure data and consecutive amendment or clustered errors division in transceiver. For the simulation there were utilized three convolutional codes for clustered errors amendment and two interleaving techniques.

Patienten mit einer dekompensierten Leberzirrhose besitzen ein hohes Risiko bakterielle Infektionen zu entwickeln. Besonders häufig kommt es dabei zu einer spontan bakteriellen Peritonitis, wobei die Letalität bis heute noch immer bei bis zu 50 % liegt. Ein wesentlicher Grund für das generelle Infektionsrisiko besteht in der Zirrhose-assoziierten systemischen Immunparalyse als Folge einer andauernden Immunstimulation. Es ist allerdings ungeklärt warum bei Patienten mit Leberzirrhose die SBP die häufigste Infektion ist, wohingegen Patienten mit malignem Aszites dafür nicht empfänglich sind. Daher war das Ziel dieser Arbeit, die Funktionseinschränkung von PMNs im Aszites von Patienten mit Leberzirrhose zu evaluieren und dafür die Fähigkeit zur Phagozytose und stimuliertem oxidativen Burst in Aszites- und korrespondierenden Blutproben zu untersuchen.

Ziel der Bachelorarbeit ist die Umsetzung und Erprobung eines Konzeptes zur Vermeidung von Überlastsituationen in paketvermittlenden Netzwerken. Hierzu wird ein Schedulingalgorithmus mit lastabhängiger Adaption der Bedienrate entwickelt -- die Burst Shaping Queue. Dieser folgt dem Konzept der Bedienratenregulierung durch Verzögerung des Bedienzeitpunktes für Pakete. Die entwickelte Schedulingeigenschaft wird in die Klasse der Closed Loop Ansätze zur Überlaststeuerung eingeordnet und gegenüber Open Loop Ansätzen abgegrenzt. Zur Leistungsuntersuchung wurde der Algorithmus als Erweiterung des Netzwerksimulator ns2 umgesetzt. Verschiedene Testreihen belegen das gewünschte Verhalten der Implementierung. Die Testergebnisse werden im Hinblick auf die Verwendbarkeit des Ansatzes und zukünftige Entwicklungsmöglichkeiten analysiert und beurteilt. / The aim of this document is the analysis, implementation and test of a concept for congestion control in packet-switched networks. A new scheduling-algorithm for a queue with load-dependent adaption of the queues' serving rate is being developed - the Burst Shaping Queue. The algorithm follows the concept of serving-rate adaption by delaying packets. The developed scheduling-strategy is being classified as a closed loop approach for congestion control and is differentiated from open loop approaches. For determining the algorithm's performance and to supply a base for further studies the algorithm is implemented as an extention for the network simulator ns2. Different tests show the desired behavior of the algorithm's implementation. The analysis and evaluation of the tests' results focus mainly on usability and extensibility of this approach.

Toll-like receptor 4 (TLR4) belongs among chief bacteria-sensing Pattern recognition receptors. Endotoxin (lipopolysaccharide, LPS) recognition by TLR4 triggers signalling leading to release of cytokines that direct leukocyte infiltration into the inflammatory site and cause swelling. Effector mechanisms that ensure pathogen elimination include phagocytosis and oxidative burst. It has been repeatedly reported that the polymorphism in TLR4 may affect host resistance to various diseases. TLR4 may be, therefore, an important molecule in host-parasite co-evolution. Herein, I focused on TLR4 amino acid substitution Q549R which is associated with ornamentation in great tits. In tits I describe immune responsiveness to LPS stimulation on morphological and molecular level and examine effects of the Q549R substitution on inflammation and general body condition. In LPS- treated individuals I found decrease in heterophil-lymphocyte ratio (H/L) that might be caused by attraction of the blood-borne cells into the inflamed tissue. This is in striking contrast with increase in H/L in PBS-treated animals resulting from the stress response. There was no effect of Q549R on general condition and haematological parameters but I revealed a significant effect of the interaction between host Q549R genotype and the type...