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Estudi de la neurodegeneració i les alteracions de la barrera hematoencefàlica en rates tractades amb àcid 3-nitropropiònicDuran Vilaregut, Joaquim 09 May 2012 (has links)
L’àcid 3-nitropropiònic (3NP) és una toxina d’origen vegetal la ingesta de la qual produeix, en humans, una síndrome neurològica que presenta una simptomatologia similar a la de la malaltia de Huntington (MH). Injectada a rosegadors o primats, la toxina s’ha utilitzat per desenvolupar models animals de la MH, ja que els produeix lesions similars a les observades a l’esmentada malaltia, consistents en una afectació específica del cos estriat del seus cervells. A nivell bioquímic, aquesta molècula inhibeix de forma irreversible la succinat deshidrogenasa mitocondrial, i per tant el complex II de la cadena respiratòria. Això provoca una disminució a la producció d’ATP, punt de posada en marxa dels mecanismes d’excitotoxicitat secundària i de producció d’espècies reactives d’oxigen i per tant, de l’estrès oxidatiu, que porten a l’activació de diferents vies metabòliques de la neurona responsables de la seva mort, com són la necrosi o l’apoptosi mediades per l’activació de calpaïnes i caspases respectivament. Pel que fa a l’apoptosi, es pensa que la reactivació del cicle cel•lular podria estar involucrada en la seva activació. Reforçant aquesta idea, nombrosos estudis han detectat activació de diferents proteïnes reguladores del cicle cel•lular en teixit post mortem de pacients afectats de malalties neurodegeneratives. Per altra banda, el 3NP produeix alteracions a la permeabilitat de la barrera hematoencefàlica (BHE) dels rosegadors tractats i, recentment, s’ha vist que un dels mecanismes que pot estar implicat en aquest fet és la digestió per part de la gelatinasa MMP-9.
Així, els objectius d’aquesta tesi consisteixen en estudiar la possible participació de la reactivació del cicle cel•lular en la neurodegeneració induïda en rates per l’administració del 3NP, i per altra banda caracteritzar les alteracions de la permeabilitat de la BHE i el paper que les gelatinases MMP-2 i MMP-9 i altres tipus cel•lulars com astròcits i micròglia hi poden jugar.
Pel que fa al primer objectiu, s’ha vist que, tot i que s’ha detectat l’activació d’elements del cicle cel•lular a la lesió dels animals tractats, la reactivació del cicle cel•lular no intervé en la posada en marxa de la neurodegeneració provocada per la toxina, i s’ha arribat a la conclusió que l’expressió d’aquests elements pot estar relacionada amb una resposta tardana encaminada a la supervivència cel•lular. A partir d’aquí, s’han estudiat diferents proteïnes que poden estar relacionades amb la mort neuronal, com ATM, p53, Akt i GSK3beta. Els resultats que s'han obtingut en aquest cas indiquen que la pèrdua de la forma activa de l’Akt i la inhibició de la GSK3beta poden estar relacionades amb la neurodegeneració induïda pel 3NP.
Pel que fa a l’estudi de les alteracions de la BHE, s’ha observat que, a la zona lesionada dels animals tractats amb 3NP, hi ha una gran alteració dels seus components com són les cèl•lules endotelials, la proteïna de les unions estretes ZO-1 i la laminina, component bàsic de la membrana basal dels vasos. Finalment, s’ha comprovat que la MMP-9 i la micròglia reactiva juguen un paper destacat a la degradació de la microvasculatura cerebral afectada per l’administració del 3NP. / 3-nitropropionic acid (3-NPA) is a natural toxin that provokes, in humans, a neurological symptomatology which is similar to that observed in Huntington’s disease (HD). When injected to rodents or primates, it produces cerebral lesions, mainly located in their striata, which are similar to those observed in the brains of HD patients. 3-NPA irreversibly inhibits mitochondrial succinate dehidrogenase, which in turn causes a decrease in ATP production that triggers secondary excitotoxicity and reactive oxygen species production. These events lead neurons to their death by necrosis or apoptosis. It has been suggested that cell cycle re-entry may be involved in the activation of the apoptotic cascade. Reinforcing this, the activation of different cell cycle elements has been detected in post mortem brains of pacients affected by neurodegenerative diseases. Furthermore, blood brain barrier (BBB) disfunction has been detected in rodents administrated with 3-NPA, and it has been recently proposed that matrix metalloproteinase-9 (MMP-9) is involved in this process.
The main objectives of this work were to study the role of cell cycle re-entry in the striatal neurodegeneration induced by 3-NPA and to characterize the alterations of BBB permeability. Regarding BBB impairment, the role of MMP-2 and MMP 9 and other cellular types such as astrocytes and microglia was considered.
Although activation of G1 phase cell cycle elements was detected in the striatal lesion of 3-NPA treated rats, it was concluded that cell cycle re-entry was not involved in the activation of the neurodegenerative process, but it might be related to a late survival response. Moreover, it was shown that the loss of the active form of Akt and the inhibition of GSK3beta might be linked to the striatal neurodegeneration induced by 3-NPA. Furthermore, severe alterations in the permeability of the BBB and in the staining pattern of some of its components such as endothelial cells, tight junctions and basement membrane were detected in the striatal lesion of treated rats. Finally, gelatinolytic activity, which was mainly attributed to MMP-9, and reactive microglia were profusely detected around the injured vessels in the striatal lesion of 3-NPA, indicating that they might play a determinant role in BBB disruption in this model
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Cos, biografia i cultures juvenils. Els estudis de cas del moviment skinhead i dels latin kings & queen a catalunyaPorzio, Laura 29 January 2009 (has links)
L'objectiu teòric de la meva tesi va ser fer dialogar la corrent d'estudi sobre les cultures juvenils i la Teoria Social del Cos, perspectiva metodològica on aquest es torna un subjecte i es construeix socialment, tot interpretant els relats biogràfics de noies i nois membres dels skinheads antifeixistes i dels latin kings & queens a Catalunya. Aquestes històries de vida són els relats incorporats (embodiment) de cada noia i cada noi, que tenen experiències sobre sí i sobre els altres perquè tenen un cos i perquè són cos. Reconstruir els itineraris corporals d'aquestes noies i d'aquests nois em va permetre reconstruir les experiències que els van portar a identificar-se amb els skinheads i els latin kings, però al mateix temps reconstruir les històries dels grups i descriure i interpretar-ne els símbols, els significats i les pràctiques corporals col·lectives. / El objetivo teórico de mi tesis ha sido hacer dialogar la corriente de estudio sobre las culturas juveniles y la Teoría Social del Cuerpo, perspectiva metodológica dónde este se vuelve un sujeto y se construye socialmente, todo interpretando los relatos biográficos de chicas y chicos miembros de los skinheads antifeixistes y de los latin kings & queens en Catalunya. Estas historias de vida son los relatos incorporados (embodiment) de cada chica y de cada chico, que tienen experiencias sobre sí y sobre los otros porque tienen un cuerpo y porque son cuerpo. Reconstruir sus itinerarios corporales me permitió reconstruir las experiencias que los llevaron a identificarse con los skinheads y los latin kings, pero al mismo tiempo me permitió reconstruir las historias de los grupos y describir e interpretar los símbolos, los significados y las prácticas corporales colectivas. / The theoretical objective of my thesis has been the creation of dialogue between the current studies on youth cultures and the Social Body Theory. In this methodological perspective the body becomes a socially constructed subject, with the interpretation of biographical stories of girls and boys of anti-fascist skinheads and the Latin Kings & Queens in Catalonia. These life stories are the stories embodied by each one of them that have experienced themselves and the others because they are one body and have a body. Rebuilding their body itineraries allowed me not only to reconstruct the experiences that led them to identify with the skinheads and the Latin Kings, but also to reconstruct the histories of groups and furthermore describe and interpret the symbols, meanings and collective body practices.
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Rooftop Gardening in an Urban Setting: Impacts and ImplicationsBarreiro, Lisa 16 April 2012 (has links)
Research on green roofs has focused on grasses, sedums, and forbs. The aims of this thesis were to determine the potential of rooftop gardens (RTGs) in an urban setting to reduce local levels of CO2, remediate storm water runoff, and provide boutique vegetables for a restaurant. The garden roof footprint was 238 ft2, with 14% covered by vegetated boxes. The soil mixture used had 96% absorbency with 54.12 gallons of the 55 gallons of precipitation that fell within the rain catcher boxes absorbed. Total biomass production was 37.98 Kg of wet biomass and 5.04 Kg of dry biomass. The amount of CO2 removed equals 0.22 Kg ft-2. RTGs have a limited capacity to help sequester CO2, but retain precipitation in amounts similar to green roofs. The restaurant was provided with 4.7 Kg (wet weight) of produce (several varieties of tomatoes, peppers, and eggplant). These results support the utility of RTGs. / Bayer School of Natural and Environmental Sciences / Environmental Science and Management (ESM) / MS / Thesis
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The "life and work" of South African HistoriographyTaylor, Justin William January 2017 (has links)
South Africa has had three periods of historiographical change. As South Africa has
transitioned from colonialism, to apartheid, to democracy, historiography has been
influenced by those in power. Post-1994 and with the onset of a democratic
government, the Nation sought to create a new historiographical framework. However,
as this attempt to build a National historiography developed questions could be raised
as to whether this historiography was inclusive of a variety of sources?
This dissertation looks at three areas regarding South African historiography. First, the
current role of Churches in South Africa in fostering historiography. Second, the
theological framework of "Ras, Volk en Nasie", the "Kairos Document", and the "Belhar
Confession". Third, the depiction of South Africa by the Church of Scotland's National
magazine "Life and Work" during 1975 – 1985.
By looking at this time period, the thesis shows that as various strands of theology
developed in South Africa, these changes had connotations within the Church of
Scotland. Life and Work shows a distinct change in attitude towards the Dutch
Reformed Church and the Black Consciousness movement.
It argues that underrepresented stories about South Africa allow for a holistic
historiography. Churches in South Africa have an opportunity to use their position
within society to develop this holistic historiography and thus, historiography becomes
a practical theological issue. / Dissertation (MTh)--University of Pretoria, 2017. / Church History and Church Policy / MTh / Unrestricted
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Synthèse et caractérisation d'oligomères de chitosane pour applications biomédicales / Synthesis and characterization of chitosan oligomers for biomedical applicationsMoussa, Amani 09 September 2019 (has links)
Les chitooligosaccharides (COS) présentent des propriétés biologiques intéressantes telles que l'activité antimicrobienne, antifongique et antitumorale. Dans ce travail, nous avons utilisé les COS pour des applications très diverses, telles que l'ingénierie des cellules neuronales (blocage de la formation du réseau périneuronal), la complexation des cations Fe2+ et Fe3+ pour la synthèse de particules supermagnatiques et enfin pour le développement de conjugués fonctionnels à base de COS. Dans le cadre de ces études en partenariat, nous avons travaillé sur l'élaboration de chitooligosaccharides à structure contrôlée afin d’étudier leurs propriétés physico-chimiques ou biologiques. Des modifications de chitooligosaccharides ont été effectuées dans ce travail de deux façons: la modification par N-substitution et la modification par le groupe aldéhyde du résidu 2,5-anhydro-D-mannofuranose (amf) à l'extrémité réductrice des chitooligosaccharides. Les premiers types de COS consistent en la désamination suivie d'une réaction de N-réacétylation afin de contrôler (partiellement) à la fois le degré moyen d'acétylation et le degré moyen de polymérisation. La seconde stratégie consiste en la synthèse de nouveaux COS fonctionnalisés à leur extrémité réductrice par amination réductrice et oximation avec différents groupes chimiques cliquables (c'est-à-dire alcyne, alcène, azide, thiol et hydrazide). En fonction des COS fonctionnalisé ciblé, différentes techniques d'analyse ont été réalisées pour analyser pleinement leurs caractéristiques structurales telles que la spectroscopie RMN, la spectrométrie de masse MALDI-TOF, la chromatographie HPLC, la spectroscopie RAMAN et la chromatographie SEC. Des structures chimiques spécifiques de chitooligosaccharides modifiés ont été étudiées dans le but de les utiliser pour moduler le réseau périneural de neurones et l'établissement de connexions synaptiques. Nous avons également montré que les COS solubles permettent la précipitation des nanoparticules supramagnétiques de Fe3O4 avec un revêtement COS en les rendant moins toxiques. Enfin, les COS fonctionnalisés à leur extrémité réductrice pourraient être des intermédiaires utiles pour le développement de nouveaux conjugués fonctionnels à base de chitosane / Chitooligosaccharides (COS) classically present several biological properties such as anti-microbial, anti-tumor and anti-fungal activity. In this work, we used COS for widely different applications, such as tissue engeneering of neuronal cells (blocking of perineuronal net formation), the complexation of iron cations (Fe2+ and Fe3+) for the synthesis of supermagnatic particle and finally for the development of advanced functional COS-based conjugates. In this partnership studies, we worked on the elaboration of controlled structure chitooligosaccharides in order to decipher their physico-chemical or biological properties. Further modification of chitooligosaccharides was performed in this thesis in two ways: modification via amine N-substitution and the modification via the 2,5-anhydro-D-mannofuranose (amf) aldehyde group located at the reducing end of chitooligosaccharides. The first COS types consist in the nitrous depolymerization followed by N-acetylation in order to (partly) control both the mean degree of N-acetylation and the degree of polymerization. The second consist in the synthesis of new COS-based building blocks functionalized at their reducing end by reductive amination and oximation with different clickable chemical groups (i.e. alkyne, alkene, azide, thiol, and hydrazide). Depending on the targeted functionalized COS, different analysis techniques were carried out to fully characterize such as NMR spectroscopy, MALDI-TOF mass spectrometry, HPLC-chromotography, RAMAN spectroscopy and SEC chromatography. Specific chitooligosaccharides were studied in the objective to use them to modulate the perineuronal net of neurons, and the establishment of synaptic connections. We also showed that water soluble COS permit the precipitation of supramagnetic Fe3O4 nanoparticles with a COS coating and succeded in decreasing their toxicity. Finally we have shown that COS-based building blocks could be useful intermediates for the development of advanced functional COS-based conjugates such as COS-b-PEG diblock copolymers
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Avaliação da produção de oligossacarídeos a partir de um subproduto de Eucalyptus /January 2019 (has links)
Resumo: --- / Doutor
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Silenciamento ou subversão? Representação do papel social da mulher no discurso perfomático das crossplayers do mangáCé, Otávia Alves 08 August 2014 (has links)
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Previous issue date: 2014-08-08 / This thesis is built on the assumption that the erasure of the female body to interpret the male is a mean of acquiring voice and power. The objective is to demonstrate, through the analysis of the verbal-visual discourse of the performances of crossplayers when interpreting male characters, that the figures of the hero and the villain in works of female authors, have power and show that for crossplayers to assume the representation of such figures, the conditio sine qua non is the silencing of the feminine. The corpus of analysis consists of two performances presented by Brazilian crossplayers: the first concerns a clipping from the manga Clover authored by the CLAMP group (composed entirely of women) focusing on the hero Kazuhiko Fay Ryu, and the second an excerpt from the manga Inuyasha, authored by Rumiko Takahashi, aiming at the villain, Sesshoumaru. The work is divided into four chapters. The first discusses concepts of Japanese pop culture, focusing on the manga (comic books). The second presents the world of cosplay practice (activity that involves representing characters derived from popular media, including the manga) and crossplay (segment in which cosplay practitioners interpret characters of the opposite sex). The third is based on the theoretical framework, in which I elaborate on a literature review of Critical Discourse Analysis (CDA), Visual Grammar, gender studies, fundamentals of Takarazuka Theater (theater company composed entirely of women) and studies on performance. The fourth chapter includes: a) the transformation of crossplayers described from supplementary materials available in a video and tutorials that illustrate the preceding steps of stage performance; b) analysis methodology, based on the model of the pentad of Burke (1973), composed of agent, act, scene, agency and proposal, to which selected categories among the other theoretical axes are added; c) the analysis of the two performances, available in DVD. In order to broaden the informative horizon tangent to the practice of performances resulting from intertextual movements with manga I include an attachment with the testimony of Brazilian crossplayers and an appendix with an account of my own experience in cos/crossplay. Along with the test results, this material is also considered in the search for an answer to the question that imposes itself from the title of the work: "Silence or subversion? The representation of the social role of women in the performative discourse of manga crossplayers / Esta tese é construída a partir da hipótese de que o apagamento do corpo feminino para interpretar o masculino é um meio de adquirir voz e poder. O objetivo é demonstrar, por meio da análise do discurso verbo-visual de performances de crossplayers ao interpretarem personagens masculinas, que as figuras do herói e do vilão, em obras de autoria feminina, possuem poder e evidenciar que, para as crossplayers assumirem a representação de tais figuras, a condição sine qua non é a do apagamento do feminino. O corpus de análise é composto por duas performances apresentadas por crossplayers brasileiras: a primeira diz respeito a um recorte do mangá Clover de autoria do grupo CLAMP (composto integralmente por mulheres) com enfoque no herói Kazuhiko Fay Ryu, e a segunda um excerto do mangá Inuyasha, da autora Rumiko Takahashi, enfocando o vilão, Sesshoumaru. O trabalho encontra-se dividido em quatro capítulos. O primeiro aborda conceitos da cultura pop japonesa, com foco nos mangás (histórias em quadrinhos). O segundo apresenta o universo da prática do cosplay (atividade que consiste em representar personagens oriundas de mídias populares, entre as quais, os mangás) e do crossplay (segmento do cosplay no qual as/os praticantes interpretam personagens do sexo oposto). O terceiro tem por base o referencial teórico, em que realizo uma revisão bibliográfica da Análise Crítica do Discurso (ACD), da Gramática Visual, dos estudos de gênero, dos fundamentos do Teatro Takarazuka (companhia teatral composta inteiramente por mulheres) e dos estudos acerca de performance. O quarto capítulo contempla: a) o processo de transformação das crossplayers, descrito a partir de materiais complementares veiculados em um vídeo e em tutoriais que ilustram esta fase anterior à apresentação no palco; b) a metodologia de análise, baseada no modelo do pentad de Burke (1973), composto por agente, ato, cena, agência e proposta, ao qual são acrescidas categorias selecionadas entre as que compõem os demais veios teóricos; c) a análise das duas performances, disponibilizadas em DVD. Com o fim de ampliar o horizonte informativo que tangencia a prática de performances resultantes de movimentos intertextuais com mangás, incluo um anexo com depoimentos de crossplayers brasileiras e um apêndice com o relato de minha experiência em cos/crossplay. Juntamente com o resultado das análises, este material é também considerado na busca de uma resposta para o questionamento que se impõe desde o título do trabalho: Silenciamento ou subversão? A representação do papel social da mulher no discurso performático das crossplayers de mangás
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La construcció del cos social: una aproximació hermenèutica als discursos que infants i adolescents elaboren sobre el cos adultFigueras Comas, Sara 22 April 2008 (has links)
La conceptualització del cos és un fenomen que històricament ha generat controvèrsia, entre altres raons perquè s'ha estudiat i interpretat des d'òptiques molt diferents segons els moments de la història, les cultures i/o les diverses disciplines que han intentat explicar-la. El posicionament en una visió complexa del cos, és a dir, aquella que entén el cos no tan sols com a fenomen biològic, sinó també com a fenomen social, ens proporciona eines evidents per analitzar-lo en la contemporaneïtat i estudiar la idoneïtat del seu tractament en el món educatiu formal, i més en concret, des de l'àrea educació física.Aquesta investigació proposa identificar els elements que utilitzen els infants i adolescents autòctons de cinquè d'educació primària i segon d'educació secundària obligatòria (ESO) d'una mateixa escola de Barcelona, per a construir la dimensió social del cos adult de sexe masculí i de sexe femení. La metodologia proposada per a la investigació és l'estudi de cas múltiple, en el que es distingirà com a mètode de recollida de dades qualitatives l'entrevista clínica de Piaget. Per altra banda, el mètode d'anàlisi de les dades qualitatives serà la grounded theory amb el suport del software d'anàlisi qualitatiu de l'ATLAS/ti en la seva versió 5. / La conceptualización del cuerpo es un fenómeno que históricamente ha generado controversia, entre otras razones porque se ha estudiado e interpretado desde ópticas muy distintas según los momentos de la historia, las culturas y/o las distintas disciplinas que han intentado explicarlo. El posicionamiento en una visión compleja del cuerpo, es decir, aquella que entiende el cuerpo no sólo como fenómeno biológico, sino también como fenómeno social, nos proporciona herramientas evidentes para analizarlo en la contemporaneidad y estudiar la idoneidad de su tratamiento en el mundo educativo formal, y más concretamente, desde el área de educación física.Esta investigación propone identificar los elementos que niños/as autóctonos de quinto de educación primaria y segundo de educación secundaria obligatoria (ESO) de una misma escuela de Barcelona, utilizan para construir la dimensión social del cuerpo adulto de sexo masculino y de sexo femenino. La metodología propuesta para la investigación es la del estudio de caso múltiple, en la se distingue como método de recogida de datos cualitativos la entrevista clínica de Piaget. Por otro lado, el método de análisis de los datos cualitativos será la grounded theory con el soporte del software de análisis cualitativo ATLAS/ti en su versión 5. / The body as a concept has always been a controversial issue because of the different approaches used to explain it through the sciences and different cultures. A complex approach to the body views it not only as a biological phenomenon, but also as a social construction. This new approach provides us with new tools to analyze the need to introduce the body as a complex reality in our formal education system through Physical Education taken as a subject.This research proposes to identify the elements selected by native children in five grades of Primary Education, and by native adolescents in their second year of Secondary Education (ESO, in the Spanish system), attending the same school in Barcelona, in order to construct the social dimension of the adult male and female body. The methodology used during the research was based on case studies, in which we differentiate two methods: as a method to collect data, the clinic Piaget interview and, as a method to analyze data, the grounded theory, with the ATLAS/ti (5th version) software support.
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Upplevelser och erfarenheter från ledare av föräldraskapsstödsprogrammet Trygghetscirkeln : En kvalitativ studie utförd i en medelstor kommun i SverigeJansson, Pernilla January 2020 (has links)
Background: Circle of Security - Parenting (COS-P) is a parenting support program that´s has establish all over the world. COS-P is an intervention program that is based on the attachment theory and focuses on strengthening the connection between parent and child. Aim: The aim of this study is to examine leaders’ experiences of the parenting support program, Circle of Security in a medium-sized municipality in Sweden. Method: A descriptive qualitative study was performed. A Semi-structured interview were conducted by an independent interviewer. Intensity sampling was used as a selection method. There were five participants in total, three from Social services and two from the Swedish Church. A qualitative content analysis was used to analyze the collected data. Results: Two main categories are presented (1) The efficacy of Circle of Security (2) Circle of Security as a method. Under each main category there are subcategories that have emerged in the analysis process. The leaders found COS-P to be effective, easily understandable, adaptable to different client groups and emotionally challenging. The leaders considered that there were development opportunities regarding the COS-P material and had shared opinions in explaining the program's adaptability. Conclusion: This qualitative study has shown that the leaders experiences of the parenting support program COS-P were largely positive, but there were also some development opportunities. / Bakgrund: Trygghetscirkeln (COS-P) är ett föräldraskapsstödsprogram som etablerats runt om i hela världen. Trygghetscirkeln är ett interventionsprogram som grundar sig i anknytningsteorin och fokuserar på att stärka anknytningen mellan förälder och barn. Syfte: Syftet med studien är att undersöka utbildade ledares uppfattningar och erfarenheter av föräldraskapsstödsprogrammet Trygghetscirkeln i en medelstor kommun i Sverige. Metod: En deskriptiv kvalitativ studie genomfördes. Semi-strukturerad intervju genomfördes av en intervjuare. Intensity sampling användes som urvalsmetod. Det var totalt fem respondenter, tre från Socialtjänsten och två från Svenska kyrkan. En kvalitativ innehållsanalys användes för att analysera insamlade data. Resultat: I resultatet presenteras två huvudkategorier (1) Trygghetscirkelns verkan (2) Trygghetscirkeln som metod. Under varje huvudkategori tillkommer underkategorier som framkommit i analysprocessen. I resultatet beskrevs Trygghetscirkeln av ledare som effektivt, lättförståeligt, anpassningsbar till olika klientgrupper och känslomässigt utmanande. Ledarna ansåg att det fanns utvecklingsmöjligheter gällande Trygghetscirkelns material och hade delade meningar i förklarningen av programmets anpassningsbarhet. Slutsats: Denna kvalitativa undersökning har visat att upplevelser och erfarenheter från ledare av föräldraskapsstödsprogrammet Trygghetscirkeln var till största del positiv men det framkom även vissa utvecklingsmöjligheter.
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Dynamic assignment protocols for multi-wavelength gigabit-PONsGliwan, A. January 2011 (has links)
The research initiatives addressed in this thesis are geared towards improving the performance of passive optical networks through the development of advanced dynamic bandwidth allocation protocols. In particular, the aim of the research undertaken is to enhance the quality of service offered by standard passive optical networks with reduced network costs. To that extent, a dynamic multi-wavelength protocol has been developed to increase the network upstream bandwidth and introduce multiple service levels to a fibre to the home-based giga-bit passive optical network. Simulation results have confirmed the reduction of the mean packet delay by adjusting the ITU-T standard G984 giga-bit passive optical network frame format by means of the introduction of extended wavelength band overlay based on the ITU-T Coarse- Wavelength Division Multiplexing grid to support the multi-wavelength functionality. To evaluate the multi-wavelength upstream operation of the newly implemented models in OPNET, 2-dimensional Dynamic Bandwidth Allocation algorithms have been introduced to manage the network resources in both the time and wavelength domains. Furthermore, the enhanced traffic allocation among the supported wavelengths in new protocol confirmed a performance improvement in the network total capacity and the mean packet delay, which demonstrates the network reliability and improves the quality of the provided service according to the subscriber service level agreement, with a minimum guaranteed bandwidth of 100 Mbit/s to fulfil applications and associated bandwidth requirements for the next generation access network.
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