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Factors contributing to the competitiveness of Lactobacillus reuteri in sourdough and rodent gutSu, Shu-Wei Unknown Date
No description available.
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Les voies de signalisation utérines à l'émergence de la diapause embryonnaire chez le vison américainLefèvre, Pavine L.C. 08 1900 (has links)
La diapause embryonnaire se manifeste par un arrêt réversible du développement embryonnaire durant la période de préimplantation et induit un retard de l’implantation. Chez le vison américain, une diapause embryonnaire obligatoire caractérise chaque gestation. Si les mécanismes de contrôle de la diapause embryonnaire obligatoire chez cette espèce sont bien connus, le rôle utérin impliqué dans la réactivation de l’embryon demeure, quant à lui, encore inconnu.
Le sujet de ce doctorat a consisté dans un premier temps à explorer l’environnement utérin à la sortie de la diapause embryonnaire afin de caractériser, dans un deuxième temps, les principaux acteurs utérins qui provoquent la réactivation de l’embryon.
Nous avons effectué une analyse du transcriptome utérin à l’émergence de la diapause embryonnaire ce qui a permis de construire une librairie de 123 séquences d’ADNc utérines différentiellement exprimées à la réactivation de l’embryon et homologues à des séquences de gènes connues chez d’autres espèces. Ces gènes sont impliqués dans la régulation du métabolisme (25 %), de l’expression génique (21 %), de la transduction de signal (15 %), du cycle cellulaire (15 %), du transport (10 %) et de la structure cellulaire (9 %), reflétant ainsi d’importantes modifications utérines à la réactivation embryonnaire. Nous avons validé l’expression différentielle de dix gènes ainsi identifiés : GDF3 (growth and differentiation 3), ALCAM (activated leukocyte cell adhesion molecule), ADIPOR1 (adiponectin receptor 1), HMGN1 (high mobility group N1), TXNL1 (thioredoxin like 1), TGM2 (tissue transglutaminase 2), SPARC (secreted protein acidic rich in cystein), et trois gènes codant pour AZIN1 (antizyme inhibitor 1), ODC1 (ornithine decarboxylase 1) et SAT1 (spermidine/spermine N1-acetyltransferase), des enzymes impliquées dans la biosynthèse des polyamines. Le patron de l’expression spatio-temporel de SPARC et d’HMGN1 illustrent spécifiquement un remodelage tissulaire et de la chromatine au niveau utérin à la sortie de la diapause embryonnaire.
Ayant mesuré une augmentation des concentrations utérines en polyamines à la reprise du développement embryonnaire, nous avons émis l’hypothèse que les polyamines seraient impliquées dans les événements menant à la sortie de la diapause. L’inhibition de la biosynthèse des polyamines par un traitement à l’ α-difluoromethylornithine (DFMO) a provoqué une diminution significative de la proliferation cellulaire dans les embryons à la réactivation, un retard du moment de l’implantation, mais n’a pas affecté le succès de la reproduction. De manière similaire, nous avons induit un état de dormance dans les cellules de trophoblaste de vison en présence DFMO dans le milieu de culture, et constaté que cet état était réversible.
En conclusion, cette étude a non seulement ouvert de nouveaux horizons quant à la compréhension du rôle utérin dans les événements menant à la sortie de la diapause embryonnaire, mais a démontré pour la première fois, l’existence de facteurs utérins indispensables à la réactivation de l’embryon: les polyamines. / Embryonic diapause is characterized by a reversible arrest of blastocyst development prior to implantation and delay in implantation. In the American mink, embryonic diapause is a characteristic of each gestation. Although the mechanisms which control obligate embryonic diapause of this species are well known, the role of the uterus involved in blastocyst reactivation remains elusive.
The subject of this doctoral research consisted first in exploring the uterine environment at the emergence of embryonic diapause in order to subsequently determine, the main factors in the uterus that provoke reactivation of the embryo.
We have undertaken an analysis of the uterine transcriptome at the emergence of embryonic diapause which has enabled us to set up a library of 123 cDNA uterine sequences differentially expressed at blastocyst reactivation, and homologue gene sequences known in other species. Twenty-five percent of these genes are implicated in genetic expression, 15 % in cell signal transduction, 15 % in cell cycle, 10 % in transport and 9 % in cell structure. All of them reflect significant uterine modifications at blastocyst reactivation. We have validated differential expression of ten genes, identified as: GDF3 (growth and differentiation 3), ALCAM (activated leukocyte cell adhesion molecule), ADIPOR1 (adiponectin receptor 1), HMGN1 (high mobility group N1), TXNL1 (thioredoxine like 1), TGM2 (tissue transglutaminase 2), SPARC (secreted protein acidic rich in cystein), and three genes encoding for AZIN1 (antizyme inhibitor 1), ODC1 (ornithine decarboxylase 1) and SAT1 (spermidine/spermine N1-acetyltransferase), which are enzymes implicated in polyamine biosynthesis. The spatio-temporal expression patterns of SPARC and HMGN1 illustrate tissue and chromatin remodelling in the uterus at the termination of embryonic diapause.
Having measured an increase in concentration of polyamines in the uterus at the resumption of blastocyst development, we have hypothetized that polyamines are implicated in the emergence of blastocysts from diapause. We inhibited polyamine biosynthesis in pregnant mink females during early blastocyst reactivation. The inhibition of polyamine biosynthesis through treatment with α-difluoromehtylornithine (DFMO) provoked a major reduction in cell proliferation in blastocysts at reactivation and a delay in the timing of implantation, but did not affect the success of reproduction. Similarly, we induced a reversible dormant state in cultured mink trophoblast cells traited with DFMO.
To conclude, not only are results of this study a breakthrough in the understanding of the role of the uterus in stimulating at the emergence of blastocysts from embryonic diapause, but also, for the very first time, they indicate the existence of uterine factors, the polyamines, that are responsible for blastocysts reactivation.
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Re-Framing Traditional Arts: Creative Process and Culturally Responsive LearningStanley, Faye Tucker January 2014 (has links)
In many ways, traditional arts in schools bear the bruises of the early years of multicultural education, and the failed practices that created what has been termed a tourist curriculum, comprised of the superficial study of folktales, festivals, foods, and facts. Consequently, the use of art forms of cultures is often approached with caution by teachers, or avoided altogether.
This thesis re-frames the use of traditional arts in the classroom through current research and knowledge, defining their efficacy and role in today’s classroom. Traditional arts are examined through the lenses of arts integration, culturally responsive pedagogical practice and creative processes. A qualitative, research portraiture methodology was employed, and executed through the lens of four case studies in order to more coherently incorporate the arts-based nature of this research. The research sites include classes studying Maori visual arts, waiata (song), and haka (dance) in Christchurch, New Zealand, chant, hula, and plant weaving at an Hawaiian charter school, and social dance and song of the Oneida tribe in the US.
Research results indicated that when teachers facilitate experiences in traditional arts in such a way that students are exposed to entry points for their own interaction with the forms, students respond with self reflection, engagement, and a tendency to elevate the status of affiliation with the culture undertaken. While students and teachers do not become conversant in the culture as a result of such study, working with traditional arts in this way may serve to break down culturally bound ways of seeing the world.
When traditional arts are employed in classrooms, they may engage students in a creative process that takes the form of embodied or physicalized, interpretive, or improvisational interactions with the forms.
When traditional arts are employed in this way, relying on creative process, they also meet goals for culturally responsive learning, legitimizing how students experience and make sense of the world.
Traditional arts provide a critical, under-utilized, strategy for embedding culture in the educational setting. In order to best meet the goals of the learning setting, traditional arts must incorporate creative processes. Hybridization of the forms, while increasing accessibility for teachers and students, must be carefully undertaken. Traditional arts utilized in this way hold potential for addressing broader curricular content.
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L'économie criminelle de la Camorra et la pratique discursive des différents points de vue dans Gomorra de Roberto SavianoMilia, Bruno 12 1900 (has links)
This thesis will study the Italian literary phenomenon Gomorra, viaggi nell'impero economico e nel sogno di dominio della Camorra. First, the focus will be on the text's hybrid nature and implications and also on its literary and intellectual inspirations (such as Truman Capote, Pier Paolo Pasolini and Leonardo Sciascia). Secondly, we will take a closer look at the structure of the novel's narrative and its literary details, in order to reveal the different processes used by Roberto Saviano to convince the reader. Interwoven in this book's central plot, we will find a main obsession: the need to understand.
Lastly, we will discuss the question of the great power treated in this novel, the one of a criminal organisation transformed by the revelations made throughout the story. These revelations will allow us to draw interesting comparisons between organized crime and merchant capitalism. For this part, we will refer to Guy Debord's La société du spectacle, and to Hannah Arendt's work on the question of totalitarianism. All of these elements will allow us to discuss the different perspectives within the narrative's framework, and more precisely, the figure of the narrator/author/character that gives Saviano's novel anthropological qualities, in the form of an ethnofiction (Augé). / Ce Mémoire cherchera a étudier le phénomène littéraire italien Gomorra, viaggio nell’impero economico e nel sogno di dominio della Camorra. Au fil de l’analyse il sera évoqué autant son caractère hybride et les implications que cela représente que les influences littéraires et intellectuelles, auquel un tel texte fait écho ( Truman Capote, Pier Paolo Pasolini, Leonardo Sciascia…). Par la suite nous nous attacherons aux structures narratives et aux particularités littéraires du roman, afin de faire ressortir les différents procédés utilisés par Roberto Saviano dans son intention de convaincre. Une obsession qui s’inscrit dans la dynamique centrale du livre, celle de comprendre.
Enfin, il sera question de la grande force qui entoure ce roman, celle d’un crime organisé rendu différent de par les révélations faites au sein du roman. De cela nous tirerons une étude comparative entre le crime organisé et le capitalisme marchand, faisant appel autant à Guy Debord et son œuvre La société du spectacle, qu’à Hannah Arendt pour ses nombreux travaux entourant la problématique du totalitarisme. Tous ces éléments nous permettront de conclure sur la particularité des points de vue, notamment avec la figure du narrateur/auteur/personnage qui nous permettra de rapprocher le roman de Roberto Saviano au travail anthropologique, dans la dynamique d’une forme d’ethno- fiction (Augé)
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Expression and Functional Analysis of pthrp1 and ihha in the Regeneration of Bones in Zebrafish Caudal FinAl-Rewashdy, Ali 18 September 2013 (has links)
The parathyroid hormone related protein (PTHrP) and Indian Hedgehog (IHH) are two secreted molecules, acting as paracrine factors during embryonic development and post-natal growth of endochondral bones. PTHrP and IHH are essential factors for the regulation of chondrocyte proliferation and differentiation. However, it has previously been shown that PTHrP and IHH are also expressed in the chick and mouse embryos intramembranous bones, which do not form through a cartilage intermediate and in which chondrocytes are absent. Similarly, the zebrafish orthologs, pthrp1 and ihha, are also expressed during the regeneration of the intramembranous bones of the fin rays of the zebrafish caudal fin. This surprising observation led us to further analyze the expression and function of pthrp1 and ihha in the regenerating fin rays. Gene expression analysis using in situ hybridization shows that pthrp1 is expressed in a stripe of cells located within the domain of expression of ihha in the newly differentiating osteoblasts in the regenerating fin rays. Also, pthrp1 expression is observed at the level of the joints between the bone segments forming the rays and co-localizes with the expression domain of evx1, a transcription factor that has been implicated in the formation of joints in the caudal fin. Furthermore, RT-PCR analyses show that pthrp2 and the pthrp receptors mRNA (pth1r, pth2r and pth3r) are also present in the fin regenerate. Finally, functional analysis shows that the knockdown of pthrp1 or ihha expression by electroporation of morpholinos induces a delay of the regenerative outgrowth of the fin. These results suggest that pthrp1 and ihha may be involved in the regulation of proliferation and differentiation of chondrocyte-like osteoblasts in the fin rays, playing a role similar to that described in the mammalian growth plate of endochondral bones. In addition, pthrp1 is possibly an important factor involved in the formation and maintenance of joints of the dermal bones of the fin rays.
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Analysis of HER2 testing in breast cancer: disparities, cost-effectiveness, and patterns of careAshok, Mahima 01 July 2009 (has links)
HER2 breast cancer is an aggressive disease that occurs in 20 - 30% of the breast cancer population. Treatment for HER2 breast cancer includes use of an anti-HER2 monoclonal antibody, trastuzumab. Testing for HER2 is of critical importance due to the adverse side effects and substantial costs associated with this anti-HER2 treatment. Currently, two kinds of tests, Fluorescence In Situ Hybridization (FISH) and Immunohistochemistry (IHC), are FDA approved for determination of HER2 status in breast cancers.
Clinical and non clinical factors that affect the choice HER2 test and the use of anti-HER2 therapy in breast cancer were analyzed using a data set containing information from six outpatient oncology clinics in the United States. The analysis showed that geographic location, cancer stage, and diagnosis date (pre- or post-publication of testing guidelines) have significant effects on choice of test. With regard to trastuzumab prescription, geographic location and HER2 status have significant effects on the prescription of trastuzumab. In addition, there was a non-significant trend for certain Medicare patients not to receive trastuzumab therapy. These findings indicate that disparities are present in breast cancer care based on geography and cancer stage, and highlight the importance of testing guidelines.
The cost effectiveness of FISH vs. IHC was determined, by considering the financial and health-related costs associated with testing and subsequent treatment as well as the accuracy of each test. The results show that FISH is the optimal choice for HER2 testing and is more cost-effective than IHC.
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Characterization of human chromosome 22 : cloning of breakpoints of the constitutional translocation t(11;22)(q23;q11) and detection of small constitutional deletions by microarray CGH /Tapia Páez, Isabel, January 2003 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.
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Pollen biology in relation to artificial hybridization in the genus ProteaVan der Walt, Izak David 03 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 1994 / 127 Leaves printed single pages, preliminary pages i-viii and numberd pages 1-118.Includes bibliography,tables and figures. / Date on t.p.: Dec. 1994. / ENGLISH ABSTRACT: Effects of pH,sucrose, boric acid and temperature on in vitro germination of pollen of
Protea repens (L.) L. cv. 'Embers' were investigated in hanging-drop culture to establish
optimum conditions for germination. Optimum values were found within ranges pH: 5 - 8,
sucroseconcentration:0.4 - 0.7 M, boric acid concentration:50 - 500 mg.e-1
, and incubation
temperature: 5 - 30°C. Storage temperature and humidity on pollen viability was studied
in four Pro tea clones. Pollen was stored at a range of temperatures and relative humidities
for up to one year and tested for ability to germinate in vitro. Pollen of P. repens cv.
'Sneyd', P. eximia cv. 'Fiery Duchess' andP. magnifica clone 'T 84 07 OS', stored in liquid
nitrogen (-196°C) and in a freezer (-14° to -18°C), retained a germination percentage as high
as that of fresh pollen regardless of humidity. The study showed that long-term storage of
protea pollen is not feasible at temperatures above O°C. The correlations between the
fluorochromatic reaction (FCR) and germinability were found to be low and nonsignificant.
Fifteen month old cryopreserved 'Sneyd' pollen was shown to retain its ability to fertilize and
set seed equal to that of fresh pollen. 'Sneyd', 'Fiery Duchess' and 'T 84 07 OS' pollen
could be repeatedly thawed and frozen in liquid nitrogen before its germinability in vitro
decreased. The morphology and size of Protea pollen was studied, using light and scanning
electron microscopy. Polymorphic grains were observed in two interspecific hybrids. Very
small differences in pollen grain size were recorded between clones/species. The male
fertility of 25 interspecific Pro tea hybrids, based on in vitro pollen germinability, was
investigated. The majority of hybrids were found to be sufficiently fertile to be used in a
breeding programme. Pistil structure and pollen tube pathways were investigated in 'Sneyd'
using light and scanning electron microscopy. The pistil had four distinct regions, consisting
of the stigma, the vertebra-shaped upper style, the heart-shaped lower style, and the ovary.
The pistil had a stylar canal along its entire length and this canal was also the route by which
pollen tubes grew to the ovary. Very low numbers of pollen tubes reached the ovary. The
breeding system of 'Sneyd' and 'Fiery Duchess' were determined from pollen tube and seed
set data, after controlled hand-pollinations. Both clones were found to be fully selfcompatible.
Very low percentages autogamous seed set were recorded. Interspecific crosses
had a low success rate. An incompatibility reaction probably occurred on the stigma and/or in the upper style regions.The attainment of maximum stigma receptivity of two Protea
cultivars was investigated by means of seed set experiments, pollen tube growth observations
and measurement of the degree of opening and closing of the stigmatic groove. Both
cultivars were found to be protandrous. The maximum stigmatic groove width of both
cultivars never exceeded the pollen grain diameter. It was concluded that Protea spp. must
be hand-pollinated two to six days after anthesis in order to obtain maximum seed set; while
for the observations of pollen tubes in the ovary, inflorescences must not be harvested before
seven days after pollination. / AFRIKAANSE OPSOMMING: Ten einde 'n optimale medium vir die in vitro-ontkieming van Protea-stuifmeel te
ontwikkel, is die effek van pH, sukrose, boorsuur, en temperatuur op die in vitro-ontkieming
van Protea repens (L.) L. cv. 'Embers'-stuifmeel deur middel van die hangdruppel-metode
ondersoek. Die volgende reekse van veranderlikes wat getoets is, is as optimaal gevind;
pH: 5 - 8, sukrosekonsentrasie: 0.4 - 0.7 M, boorsuurkonsentrasie: 50 - 500 mg.e-1 en
inkubasietemperatuur: 5 - 30°C. Die invloed van bergingstemperatuur en humiditeit op
stuifmeel-Iewenskragtigheid is in vier Protea-klone ondersoek. Stuifmeel is gestoor by 'n
reeks temperature en relatiewe humiditeite vir tot eenjaar, en vir in vitro-ontkiemingsvermoe
getoets.' Stuifmeel van P. repens <?v. 'Sneyd', P. eximia cv. 'Fiery Duchess', en P.
magnifica kloon'T 84 07 OS', in vloeibare stikstof (-196°C) en in 'n vrieskas (-14° tot -
18°C) geberg, het 'n ontkiemingspersentasie gelykstaande aan die van vars stuifmeel
gehandhaaf, ongeag van die humiditeit. Hierdie studie het verder aangetoon dat
langtermynberging van Protea-stuifmeel bokant O°C me die moeite werd is me. Die
korrelasie tussen die fluorochromatiese reaksie (FCR) en ontkieming was laag en me
betekemsvol me. 'Sneyd' -stuifmeel wat vir 15 maande in vloeibare stikstof gestoor is, het
die bevrugtings- en saadsetvermoe gelykstaande aan vars stuifmeel behou. 'Sneyd', 'Fiery
Duchess' en 'T 84 07 OS'-stuifmeel kon herhaaldelik in vloeibare stikstof gevries en ontdooi
word voordat hul ontkiemingsvermoe afgeneem het. Die morfologie en grootte van Proteastuifmeel
is deur middel van lig- en skandeerelektronmikroskopie bestudeer. Polimorfiese
stuifmeelkorrels is in twee interspesie-hibriede waargeneem. Baie klein verskille in
stuifmeelkorrelgroottes het tussen klone/spesies voorgekom. Die manlike vrugbaarheid van
25 Protea-interspesiehibriede, gebaseer op die in vitro-ontkiembaarheid, is ondersoek. Dit
is gevind dat die meerderheid hibriede 'n voldoende graad van vrugbaarheid het om in 'n
teelprogram te gebruik. Die stamperstruktuur en stuifmeelbuiswee in P. repens is deur
middel van lig- en skandeer-elektronmikroskopie ondersoek. Die stamper bestaan uit vier
kenmerkende gebiede, naamlik die stempel, die werwelvormige bo-styl, die hartvormige
onderstyl, en die vrugbeginsel. Die stamper het 'n stylkanaal regdeur die totale lengte van
die stamper, en hierdie kanaal is ook die weg waarvolgens stuifmeelbuise na die vrugbeginsel gegroei het. Min stuifmeelbuise het die vrugbeginsel bereik. Die teelsisteem van 'Sneyd'
en 'Fiery Duchess' is deur middel van stuifmeelbuis- en saadsetdata na gekontroleerde
handbestuiwings ondersoek. Beide kIone was ten volle selfverenigbaar. Die persentasie
outogame saadset was baie laag. Interspesiekruisings het 'n baie lae sukses gehad. Dit is
voorgestel dat die onverenigbaarheidsreaksie in die stempel en/of in die bopunt van die styl
plaasvind. Die bereiking van maksimum stempelontvanklikheid van twee Protea-cultivars
is deur middel van saadseteksperimente, stuifmeelbuisdata en waarnemings van die oop- en
toemaak van die stempelgroef ondersoek. Beide cultivars was protandries. Die maksimum
stempelgroefwydte het nooit die stuifmeelkorreldeursnee oorskry nie. Dit is afgelei dat
Protea-spesies twee tot ses dae na antese handbestuif moet word vir optimale saadset. Vir
die waarneming van stuifmeelbuise in die vrugbeginsel, moet bloeiwyses nie voor sewe dae
na bestuiwing geoes word nie.
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POÉTICA DIGITAL: CRIAÇÃO COLABORATIVA NO FLUXO COMUNICACIONAL / DIGITAL POETRY: COLLABORATIVE CREATION IN THE COMMUNICATION FLOWSchraiber, Rogério Tubias 11 January 2010 (has links)
Taking into account the possibilities of the current area of digital technology, the communicational media offer new developments to art proposals in which the public
can be more active. Thus, this dissertation brings a proposal in visual poetic developed collaboratively on an Orkut contacts network. In this network creative
actions had as developing space their own communication flow. The choice of that space is justified by the significant importance that digital media occupy more and
more space in people s lives. Therefore, is attempted to investigate a collaborative creating process which depends of the interference and of suggestions from the
virtual public itself. The proposal was to realize interferences and manipulations in images of religious and sexual content, and in fist fights scenes, creating other
compositions with the combination of these fragments. They are themes present in everyday life, often trivialized by the excess of exhibition. This condition was exploited in the poetic process by the interactors so that the resulting digital compositions bring new reading possibilities about their contents. Resultants from the
poetic proposal, such compositions remain in the Orkut network of the research where they can be seen, and these images can also be projected with the use of projectors in conventional exhibition spaces. / Levando em consideração as possibilidades do atual contexto tecnológico-digital os meios comunicacionais oferecem novos desdobramentos para propostas artísticas em que o público pode estar mais presente. Assim, a presente dissertação traz uma proposta em poéticas visuais desenvolvida de modo colaborativo em uma rede de contatos de Orkut. Nessa rede as ações criativas tiveram como espaço de desenvolvimento o seu próprio fluxo comunicacional. A escolha do referido espaço
se justifica pela significativa relevância que os meios de comunicação digital passam a ocupar cada vez mais na vida dos sujeitos. Para tanto, buscou-se investigar um
processo de criação colaborativo cujo desenvolvimento dependesse das interferências e sugestões do próprio público virtual. A proposta consistiu em realizar manipulações em imagens de conteúdo religioso, sexual e em cenas de lutas
corporais, criando outras composições com a combinação de fragmentos dessas. São temas presentes na vida cotidiana muitas vezes banalizados pelo excesso de exibição. Essa condição foi explorada no processo poético pelos colaboradores de modo que as composições digitais resultantes despertaram novas possibilidades de
leituras sobre seus conteúdos. Resultantes da proposta poética, tais composições permaneceram na rede Orkut da pesquisa onde podem ser visualizadas podendo, também, serem projetadas com o uso de projetores multimídia em espaços convencionais de exposição.
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Arquitetura multiagente baseada em nuvem de part?culas para hibridiza??o de metaheur?sticasSouza, Givanaldo Rocha de 25 October 2013 (has links)
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Previous issue date: 2013-10-25 / This thesis proposes an architecture of a new multiagent system framework for hybridization
of metaheuristics inspired on the general Particle Swarm Optimization framework (PSO). The
main contribution is to propose an effective approach to solve hard combinatory optimization
problems. The choice of PSO as inspiration was given because it is inherently multiagent, allowing
explore the features of multiagent systems, such as learning and cooperation techniques.
In the proposed architecture, particles are autonomous agents with memory and methods for
learning and making decisions, using search strategies to move in the solution space. The concepts
of position and velocity originally defined in PSO are redefined for this approach. The
proposed architecture was applied to the Traveling Salesman Problem and to the Quadratic Assignment
Problem, and computational experiments were performed for testing its effectiveness.
The experimental results were promising, with satisfactory performance, whereas the potential
of the proposed architecture has not been fully explored. For further researches, the proposed
approach will be also applied to multiobjective combinatorial optimization problems, which are
closer to real-world problems. In the context of applied research, we intend to work with both
students at the undergraduate level and a technical level in the implementation of the proposed
architecture in real-world problems / A presente tese prop?e uma arquitetura multiagente para hibridiza??o de metaheur?sticas, inspirada
na t?cnica de Otimiza??o por Nuvem de Part?culas, e tem como principal contribui??o a
proposta de uma abordagem efetiva para resolu??o de problemas de otimiza??o combinat?ria. A
escolha da Otimiza??o por Nuvem de Part?culas como inspira??o deu-se pelo fato desta t?cnica
ser inerentemente multiagente, permitindo explorar os recursos dos sistemas multiagente, tais
como as t?cnicas de aprendizado e coopera??o. Na arquitetura proposta, as part?culas s?o agentes
aut?nomos com mem?ria e m?todos de decis?o e de aprendizagem, utilizando estrat?gias de
busca para se moverem no espa?o de solu??es. Os conceitos de posi??o e velocidade, originalmente
definidos na Otimiza??o por Nuvem de Part?culas, s?o redefinidos para esta abordagem.
A arquitetura proposta foi aplicada ao Problema do Caixeiro Viajante e ao Problema Quadr?tico
de Aloca??o, realizando experimentos computacionais que comprovaram sua efetividade. Os
resultados dos experimentos foram bastante promissores, apresentando desempenho satisfat?rio,
considerando que o potencial da arquitetura proposta ainda n?o foi totalmente explorado. Em
pesquisas futuras, a abordagem proposta ser? aplicada a problemas de otimiza??o combinat?ria
multiobjetivo, os quais s?o mais pr?ximos aos problemas do mundo real. No ?mbito da pesquisa
aplicada, pretende-se trabalhar tanto com alunos em n?vel de gradua??o como em n?vel t?cnico
a aplica??o da arquitetura proposta em problemas pr?ticos do mundo real
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