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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Avaliação comportamental e neurobiológica da memória no lagarto Tropidurus hispidus (SPIX, 1825 ; Squamata : Tropiduridae) / Behavioral and neurobiological evaluation of memory in lizard Tropidurus hispidus (Spix, 1825; Squamata: Tropiduridae)

Santos, Luciano de Gois 23 May 2016 (has links)
In the group of reptiles, the ability to form memories is still much discussed and neuroanatomical data have suggested the existence of homologies between the areas of the hippocampus and amygdala of mammals and correlated structures of the telencephalon of reptiles. However, there is little functional evidence of these structures in reptiles to give support to this proposal homology. Faced with this situation, this study aimed to conduct a behavioral and neurobiological evaluation of memory in lizards species Tropidurus hispidus. For this, were used 50 lizards adult males, which after 4 days of accommodation were distributed in two experiments: the Experiment 1, aversive memory (n = 40); and the Experiment 2, spatial memory (n = 10). In Experiment 1, the animals were divided into three groups (Control, n = 8; Neutral Stimulus, n = 16; Aversive Stimulus, n = 16). The Control group did not participate in the behavioral steps, since the Neutral Stimulus group was exposed to an empty metal cage, while the Aversive Stimulus group was exposed to a domestic cat. Then all the animals in the Control group and half of the animals Neutral Stimulus and Stimulus Aversive groups had their brains perfused with paraformaldehyde 4% for subsequent analysis. The remaining animals of Neutral and Aversive Stimulus groups returned to the accommodation terrarium and, after 24 hours, passed by a rechallenge to local display of the stimulus, then also had their brains perfused with paraformaldehyde 4%. After fixation, brains were all collected subjected to a imustotoquímica detection technique the ZIF-268, a protein involved in mediating plasticity which occurs during memory formation. We found that during exposure to cat lizards of Aversive Stimulus group had a higher freezing time (p <0.001) and a smaller number of initiated movements (p <0.001) and visited quadrants (p <0.001) when compared with Neutral Stimulus group. Also found that during the re-exposure to aversive environment, the animals Aversive Stimulus group had a higher freezing time (p <0.001) and a smaller number of initiated movements (p <0.001) and visited quadrants (p <0.001), suggesting so that exposure to cat served adequately as an aversive stimulus. There was also an increase in the number of Zif-268 positive cells in regions of the reptilian hippocampus and amygdala lizards Stimulus Aversive group during exposure to cat (p = 0.005 and p = 0.039, respectively) and on re-exposure to aversive context (p = 0.001 and p = 0.009, respectively). In experiment 2, lizards underwent an adaptation of the Morris water maze, where 3 times a day for 19 days, the animals had performed attempts to find a submerged platform. We found a negative correlation (p = 0.012) the time to reach the platform and over the days, indicating an improvement in the performance of lizards in the task. Thus, the present study provided evidence that males of T. hispidus are capable of forming aversive and spatial memories, and that there is an involvement of the hippocampus and amygdala in aversive memory. / No grupo dos répteis, a capacidade de formar memórias é ainda muito discutida e dados neuroanatômicos têm sugerido a existência de homologias entre as áreas do hipocampo e amígdala de mamíferos e estruturas correlatas no telencéfalo de répteis. Contudo, existem poucas evidências funcionais dessas estruturas reptelianas para que forneçam suporte a essa proposta de homologia. Diante de tal conjuntura, esse trabalho teve como objetivo realizar uma avaliação comportamental e neurobiológica da memória em lagartos da espécie Tropidurus hispidus. Para isso foram utilizados 50 lagartos machos adultos, que após 4 dias de acomodação, foram distribuídos em dois experimentos: o Experimento 1, de memória aversiva (n=40); e o Experimento 2, de memória espacial (n=10). No Experimento 1 os animais foram divididos em três grupos (Controle, n=8; Estímulo Neutro, n=16; Estímulo Aversivo, n=16). O grupo controle não participou das etapas comportamentais, já o grupo Estímulo Neutro foi exposto a uma gaiola metálica vazia, enquanto o grupo Estímulo Aversivo foi exposto a um gato doméstico. Em seguida, todos os animais do grupo Controle e metade dos animais dos grupos Estímulo Neutro e Estímulo Aversivo tiveram seus cérebros perfundidos com paraformaldeido 4% para posterior análise. Os animais restantes dos grupos Estímulo Neutro e Estímulo Aversivo foram colocados de volta no terrário de acomodação e após 24 horas passaram por uma reexposição ao local da exibição dos estímulos, então também tiveram seus cérebros perfundidos com paraformaldeido 4%. Após a fixação, todos os cérebros coletados foram submetidos a uma técnica de detecção imustotoquímica de Zif-268, uma proteína envolvida na mediação da plasticidade que ocorre durante a formação de memórias. Verificamos que, durante a exposição ao gato, os lagartos do grupo Estímulo Aversivo apresentaram um maior tempo de congelamento (p<0,001) e um menor número de deslocamentos iniciados (p<0,001) e de quadrantes visitados (p<0,001), quando comparados com o grupo Estímulo Neutro. Verificamos também que, durante a reexposição ao contexto aversivo, os animais do grupo Estímulo Aversivo apresentaram um maior tempo de congelamento (p<0,001) e um menor número de deslocamentos iniciados (p<0,001) e de quadrantes visitados (p<0,001), sugerindo assim que a exposição ao gato atuou adequadamente como um estímulo aversivo. Observou-se também um aumento do número de células Zif-268 positivas nas regiões do hipocampo reptiliano e na amígdala dos lagartos do grupo Estímulo Aversivo, durante a exposição ao gato (p=0,005 e p=0,039, respectivamente) e na reexposição ao contexto aversivo (p=0,001 e p=0,009, respectivamente). No experimento 2, os lagartos foram submetidos a uma adaptação do labirinto aquático de Morris, onde, 3 vezes por dia, durante 19 dias, os animais realizaram tentativas de encontrar uma plataforma submersa. Constatamos uma correlação negativa (p=0,012) do tempo para chegar à plataforma e o passar dos dias, indicando uma melhoria no desempenho dos lagartos na tarefa. Assim, o presente estudo forneceu indícios que machos de T. hispidus são capazes de formar memórias aversivas e espaciais, e que há um envolvimento do hipocampo e amígdala na memória.
22

Desconvolução não supervisionada por filtros de erro de predição não lineares e recorrentes e sistemas imunologicos artificiais / Unsupervised deconvolution by nonlinear recurrent prediction-error filters and artificial immune systems

Wada, Cristina 01 November 2010 (has links)
Orientador: Romis Ribeiro de Faissol Attux / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-15T11:06:22Z (GMT). No. of bitstreams: 1 Wada_Cristina_M.pdf: 4155297 bytes, checksum: 8683ce097ae6eab2c4bc3f3cae097225 (MD5) Previous issue date: 2010 / Resumo: Na transmissão de dados através de um canal ocorrem distorções que podem eventualmente levar a níveis inaceitáveis de degradação.Uma distorção bastante comum nesse cenário é a interferência intersimbólica ,que é a conseqüência do espalhamento temporal do sinal de informação.Para mitigar essa Interferência ,é usual empregar um equalizador ,que pode ser adaptado de modo supervisionado ou não upervisionado. Uma solução clássica no caso não supervisionado é fazer uso do critério de mínimo erro quadrático médio de predição.Sabe-se que tal abordagem ,no contexto linear,é eficiente apenas para canais de fase mínima ou máxima.Para lidar com canais de fase mista ,é preciso recorrer a estruturas não lineares. Neste trabalho ,investigaremos a relevância ,nesse contexto,do uso de preditores não lineares contendo laços de realimentação .Analizar-se-á o desempenho de estruturas neurais recorrentes sob um conjunto representativo de canais ,de modo a permitir a investigação dos efeitos da memória sobre o processo de desconvolução.O processo adaptativo será conduzido por um sistema imunológico artificial,dotado de significativo potencial de busca global e robustez a soluções instáveis / Abstract: When data is transmitted trough a channel, it may be subject to several sorts of distortion that might cause unacceptable level of degradation. A very usual type of distortion is the intersymbol interference ,which is a consequence of the temporal spread of the information-bearing signal .To mitigate this interference ,it is usual to employ an equalizer ,which can be adapted either in a supervised or an unsupervised manner. For the latter case, a predictive structure, optimized according to the mean squared error criterion, is a classical solution. In the linear context, it is known that this approach is efficient only for minimum- or maximum-phase channels: to deal with mixed-phase channels, it is necessary to resort to nonlinear structures. In this work, we investigate the relevance, in this context, of the use of nonlinear predictors with feedback loops. The performance of nonlinear neural structures is analyzed in asset of representative channels, in order to form a better understanding of the effect of the channel memory on the signal and to make use of it in the deconvolution process. An optimization algorithm based on the concept of artificial immune systems is applied in the adaptation of predictors, due to its powerful global search capabilities and robustness to unstable solutions / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica
23

Les bénitiers de Nouvelle-Calédonie : nouvelles espèces et échelles spatiales de connectivité chez Tridacna maxima et Hippopus hippopus / Giant clams of New Caledonia : new species and spatial scales of connectivity among Tridacna maxima and Hippopus hippopus

Tiavouane, Josina 29 June 2016 (has links)
Malgré leur rôle fonctionnel au sein des écosystèmes coralliens, les populations de bénitiers (Tridacninae) sont en déclin à travers le monde en raison de leur surexploitation. En Nouvelle-Calédonie, 1 à 9 tonnes sont prélevées par an. Dans ce contexte, cette thèse a pour principaux objectifs de fournir des indications quant aux connectivités démographiques et évolutives des populations de deux espèces de bénitiers en Nouvelle-Calédonie, Tridacna maxima et Hippopus hippopus afin d'estimer les échelles spatiales de dispersion larvaire, comprendre leur dynamique et proposer des mesures de conservation adaptées. La connectivité des populations a été estimée via l'analyse de marqueurs génétiques microsatellites spécifiquement développés pour ces deux espèces. L'échantillonnage a permis l'identification de deux nouvelles espèces en Nouvelle-Calédonie. A l'échelle d'un récif et de quelques kilomètres, les tests de parenté montrent des taux d'auto-recrutement variables, jusqu'à 8% pour T. maxima dans le lagon sud-ouest et 29% pour H. hippopus dans le lagon nord-est. Les échelles spatiales de dispersion larvaire varient selon les espèces, jusqu'à au moins 35km pour H. hippopus. A l'échelle du territoire, les populations de bénitiers sont peu structurées, indiquant une connectivité évolutive certaine. Néanmoins, des différences significatives ont été observées entre la Grande Terre et Chesterfield, les Iles Loyautés et les atolls d'Entrecasteaux pour H. hippopus et entre la côte ouest et les Îles Loyautés pour T. maxima. Ces résultats fournissent d'importants éléments de réponse relatifs aux échelles spatiales de dispersion des bénitiers en Nouvelle-Calédonie. / Despite their functional role in coral reef ecosystems, giant clams (Tridacninae) are in decline worldwide due to their overexploitation. In New Caledonia, 1 to 9 tons are harvested per year. In this context, the main objectives of this thesis are to provide information about the demographic and evolutionary population’s connectivity for two species of giant clams in New Caledonia, Tridacna maxima and Hippopus hippopus, in order to estimate the spatial scales of larval dispersal, understand their population dynamics and propose appropriate conservation measures. The connectivity of populations was estimated by analyzing microsatellite genetic markers specifically developed for these two species. Sampling allowed the identification of two new species in New Caledonia. At reef scale and up to a few kilometers, parentage analysis showed that giant clam populations have varying self-recruitment rates, up to 8% for T. maxima in southwest lagoon and 29% for H. hippopus in northeastern lagoon. The spatial scales of larval dispersal varied for the two species, up to at least 35km for H. hippopus. At the scale of the territory, giant clam populations showed a weak genetic structure, highlighting evolutionary connectivity among sampled sites. However, significant differences were observed between the Mainland and Chesterfield, Loyalty Islands and Entrecasteaux for H. hippopus and between the west coast and the Loyalty Islands for T. maxima. These results provide important answers related to the spatial scales of larval dispersal in giant clams in New Caledonia.
24

Algoritmos Evolutivos aplicados ao Classificador baseado em Segmentos de Reta / Evolutive Algorithms applied to the Straight Line Segment Classifier

Rosario Alejandra Medina Rodríguez 03 July 2012 (has links)
Nos ultimos anos o uso de tecnicas de aprendizado computacional tornou se uma das tarefas comumente realizadas, pois tem inumeras aplicacoes de reconhecimento de padroes, tais como: reco- nhecimento de voz, classificacao de texto, reconhecimento facial, diagnostico por imagens medicas, entre outras. Dessa forma, um grande numero de tecnicas que lidam com este tipo de problema tem sido desenvolvido ate o momento. Neste trabalho apresentamos uma alternativa para melhorar a taxa acerto de classificacao do classificador binario SLS, que apresentou resultados comparaveis com as SVMs. Nesse metodo, o Gradiente Descendente e utilizado para otimizar a posicao final dos conjuntos de segmentos de reta que representarao cada classe. Embora convirja rapidamente a um valor otimo, muitas vezes e possivel o algoritmo parar em uma regiao de otimos locais, que nao representa o minimo global. Dado esse problema, foram utilizados diferentes algoritmos evolutivos em combinacao com o Gradiente Descendente a fim de melhorar a acuracia do classificador SLS. Adicionalmente a aplicacao de algoritmos evolutivos na fase de treinamento do classificador SLS, foram exploradas duas propostas: (i) explorar o uso de diferente numero de segmentos de reta para representar a distribuicao de dados de cada classe. Dado que no algoritmo original do metodo SLS o numero de segmentos de reta e igual para cada classe, o qual pode significar alguma perda de acuracia ou sobreposicao dos segmentos de reta; (ii) estimar a melhor combinacao de segmentos de reta a serem usados para cada classe. O uso de diferentes quantidades de segmentos de reta por classe pode ser de ajuda na obtencao de melhores porcentagens de acerto, mas determinar uma quantidade otima que permita representar cada classe, e um trabalho dificil. Assim, usamos o algoritmo X-Means, que e um algoritmo de agrupamento, para estimar o numero de segmentos de reta. As propostas exibiram bons resultados que possibilitam a aplicacao do classificador SLS, com um algoritmo de treinamento hibrido, em problemas reais. / During the past years, the use of machine learning techniques have become into one of the most frequently performed tasks, due to the large amount of pattern recognition applications such as: voice recognition, text classification, face recognition, medical image diagnosis, among others. Thus, a great number of techniques dealing with this kind of problem have been developed until now. In this work, we propose an alternative training algorithm to improve the accuracy of the SLS binary Classifier, which produces good results that can be compared to Support Vector Machines. In that classifier, the Gradient Descent method has been used to optimize the final positions of two sets of straight line segments that represent each class. Although, this method quickly converges to an optimum, it is possible that the algorithm stops at a local optimum region, which does not guarantee a global minimum. Given that problem, we combine evolutive optimization algorithms with the gradient descent method to improve the accuracy of the SLS Classifier. In addition to our proposal of using evolutive algorithms, we also developed two proposals: (i) we explore the use of different number of straight line segments to represent the data distribution. Since the original SLS classifier algorithm uses the same number of segments for each class, which could lead to a loss of accuracy or straight line segments overlapping. So, using different number of segments could be the way to improve the accuracy; (ii) estimate the best combination of straight line segments to represent each class. Finding an optimal combination, can be a very difficult problem, so we propose the X-Means algorithm to determine the number of segments. The proposed methodology showed good results which can be used to solve some other real problems with the SLS classifier using the proposed hybrid training algorithm.
25

Aufbau eines Screeningverfahrens zur Durchmusterung von Variantenbibliotheken der T7-RNA-Polymerase hinsichtlich des Einbaus 2’-Methoxy-modifizierter Nucleotide: Aufbau eines Screeningverfahrens zur Durchmusterung vonVariantenbibliotheken der T7-RNA-Polymerase hinsichtlich desEinbaus 2’-Methoxy-modifizierter Nucleotide

Nöbel, Nico 23 August 2011 (has links)
Thema dieser Arbeit ist die evolutive Optimierung der T7-RNA-Polymerase. Zur Stabilisierung technischer oder therapeutischer RNA-Moleküle gegenüber RNAsen wäre es wünschenswert eine RNA-Polymerase zu generieren, welche RNA vollständig aus 2’- modifizierten Nucleotiden synthetisieren kann. Zu diesem Zweck wurde ein kombiniertes Selektions- und Screeningverfahren zur Durchmusterung von Variantenbibliotheken der T7- RNA-Polymerase hinsichtlich des Einbaus von 2’-Methoxy-modifizierten Nucleotiden in RNA entwickelt. Es wurden ein gut handhabbarer, cis-regulierter Expressionsvektor sowie ein Selektionsplasmid erzeugt, die zusammen in E. coli ein in-vivo-Selektionssystem bilden, mit dessen Hilfe man Zellen, welche T7-RNA-Polymerase-Aktivität zeigen anhand ihrer grünen Fluoreszenz identifizieren konnte. Durch error-prone PCR wurden Mutantenbibliotheken generiert, und diese in das Selektionssystem eingesetzt. So konnte die Anzahl der potentiell zu testenden Varianten erheblich gesenkt werden. Zur Bestimmung der T7-RNA-Polymerase- Aktivität mit 2’-Methoxy-modifizierten Nucleotiden wurde ein Fluoreszenz-basierendes Assay etabliert. Dieses Assay, das nicht mit radioaktiv-markierten Nucleotiden arbeitete und keinen gelelektrophoretischen Separationsschritt benötigte, konnte in allen Schritten zur parallelen Bearbeitung von 96 Proben in einem Mikrotiterplatten-Format angepasst werden, so dass es prinzipiell hochdurchsatzfähig war und sich zum Screening umfangreicher Variantenbibliotheken eignete. Die Assay-Reaktion kann dabei auch unkompliziert auf ein Screening von RNA- oder DNA-Polymerase-Bibliotheken hinsichtlich anderer Eigenschaften der Polymerase-Aktivität übertragen werden.
26

A prova ilícita no processo civil constitucional: (in)admissibilidade e consequências jurídicas

Teixeira, Wendel de Brito Lemos 06 February 2013 (has links)
La presente dissertazione si propone di investigare l ammissibilità o meno della prova illecita nella fase attuale del processo civile e quali sono le conseguenze giuridiche procesuale di questa (in)ammissibilità. A questo scopo, si esaminano le fasi evolutive del processo civile e si giunge alla conclusione dell esistenza di una nuova fase, chiamata neoprocessualismo ovvero processo civile costituzionale, con caratteristiche proprie. Si studia, altresì, la relazione della verità e della prova, eleggendo all interno delle principali teorie della conoscenza (teorie della verità) la logica-razionale del linguaggio, indicando essere quest ultima quella che più si trova in consonanza con la realtà attuale del Diritto e della prova nel processo civile costituzionale. Ancora, si indaga sul concetto di prova, difendendo la possibilità di una concezione unitaria, e viepiù si analizzano le sue caratteristiche, i suoi effetti e le sue limitazioni. Si studia, successivamente, la prova illecita nel suo sembiante storico e nelle principali legislazioni straniere, oltre al suo concetto ed alle teorie tradizionali riguardo la sua ammissibilità. Cerchiamo di contribuire alla sistematizzazione delle prove illecita nella procedura civile, proponendo l\'analisi di tale istituto nell a prospettiva jus-filosofica (neoprocessualsimo e verità logica ragionevole del linguaggio) che culmina nel giusto processo, di ammissibilità delle prove relative illegale. / A presente dissertação busca investigar a admissibilidade ou não da prova ilícita, na atual fase do processo civil, e quais as consequências jurídicas no processo dessa (in)admissibilidade. Para tanto, examinam-se as fases evolutivas do processo civil e chega-se à conclusão sobre a existência de uma nova fase chamada neoprocessualismo ou processo civil constitucional, portadora de características próprias. Estuda-se ainda a relação entre a verdade e a prova, elegendo dentre as principais teorias do conhecimento (teorias da verdade) a teoria da lógico-razoável da linguagem, apontando ser esta a que mais se coaduna com a realidade atual do Direito e da prova no processo civil constitucional. Investiga-se também o conceito de prova; defende-se a possibilidade de um conceito unitário e analisam-se suas características, efeitos e limitações. Estuda-se depois a prova ilícita no seu aspecto histórico e nas principais legislações estrangeiras, além de seu conceito e das teorias tradicionais sobre sua admissibilidade. Tenta-se, assim, contribuir para a sistematização da prova ilícita do processo civil, propondo-se a análise de tal instituto numa perspectiva jus-filosófico (neoprocessualismo e verdade lógico-razoável da linguagem) que culmina no justo processo, por meio da admissibilidade relativa da prova ilícita. / Mestre em Direito Público
27

Résistance à la cavitation : des mécanismes physiologiques à la génétique évolutive : de la bulle aux gènes / Resistance to cavitation : from physiological mechanisms to evolutionary quantitative genetic : from the bubble to genes

Lamy, Jean-Baptiste 13 March 2012 (has links)
Force est de constater que les dépérissements forestiers augmentent. Ces observations vont de pairs avec l’accroissement des événements climatiques extrêmes. Aussi dans ce contexte, il est nécessaire d’identifier denouveaux caractères de resistance à la sécheresse. La résistance à la cavitation est actuellement le meilleurmarqueur de la survie d’une espèce à la sécheresse.Cette thèse avait deux objectifs : (i) comprendre le mécanisme de propagation de la cavitation dans le xylèmechez les gymnospermes. (ii) Quantifier la variation phénotypique in situ de ce caractère chez Pinus pinaster ainsique (iii) quantifier la variation génétique, et sa plasticité phénotypique.La démarché a été la suivante (i) une étude interspécifique de la résistance à la cavitation a été couplé à desmesures micro-anatomiques. (ii) Pour le volet intraspécifique, nous avons phénotypé 6 populations dans deuxtest de populations-descendances, ainsi qu’en population naturelles in situ.La propagation de l’embolie chez les Pinaceae et les ex-Taxodiaceae pourrait être due au passage du germe d’air(rupture capillaire) à travers des nanopores dans le torus. En effet, la pression de rupture d’un ménisque air-sèveest corrélée à l’entrée de l’air dans le xylème (P12). Alors que la variation interspécifique est grande, la résistanceà la cavitation varie faiblement au sein d’une espèce. Ainsi les populations provenant de climat contrasté neprésentent pas ou peu de différence génétique (en test de provenance) ou en populations naturelles in situ. Cecaractère présente une plasticité phénotypique mais faible comparée à celle de la croissance en hauteur parexemple. La comparaison entre la variation génétique entre populations et la variation des marqueurs neutresentre ces mêmes populations montrent que la variation de ce caractère semble réduite par l’architecturegénétique sous-jacente. La resistance à la cavitation est vraisemblablement un trait canalisé. / Several review reported global forest die-back that are caused, directly or indirectly, by extreme climatic events(like heat waves or prolonged drought). In this context, there is an urgent need to identify new traits to tracedrought tolerance. Resistance to cavitation is one of the best proxy for survival during extreme drought.The aim of this work was (i) to understand how spreads cavitation in the vascular pathway of gymnosperms (ii)to quantify the phenotypic variation of resistance to cavitation for Pinus pinaster species, (iii) to determine theamount of the genetic variation and phenotypic plasticity available for this trait.A micro-anatomy study was coupled to measurement of resistance to cavitation for various species to foundwhere air-seeding occurs in the bordered pit. To quantify the variability of resistance to cavitation, wephenotyped 506 genotypes using to replicated provenance-progeny trials and on natural in situ populations.The spread of embolism for Pinaceae and ex-Taxodiaceae could be due to minute pore in tori, which are remainsof secondary plasmodesmata. We found that the pressure needed to break a water/air meniscus in these minutepores is correlated with the xylem air entry (P12). Despite the great variability of resistance to cavitation betweenspecies, we found low variability within species. Most of the variability is within population, rather than betweenpopulations. The phenotypic plasticity of resistance to cavitation is low compare to growth traits. Comparisonbetween QST and FST shows that populations exhibit less variation compare to what it is expected under geneticdrift. The variation of resistance to cavitation seems to be narrowed by the genetic architecture, which is the signof canalisation.
28

Study of evolution in human resources management programs in organizations. Application of "Path Dependence" and "Cladistics"

Perelló Marín, María Rosario 01 September 2015 (has links)
[EN] This doctoral thesis analyses human resources management evolution in organizations. That is, changes introduced throughout people management. The key objective is to analyze how organizations evolve and change over time by means of human capital. Recent years have demonstrated that levels of adjustment and change required by organizations in order to adapt to a changing environment, are increasingly high. One of the main drivers behind this organizational change, is the introduction of new programs and tools that help organizations to improve their business performance. This work is focused on the identification and analysis of such programs in the field of human resources management. In particular: what sort of HRM practices are implemented, in what sort of organization, at which point in time, and finally, in which order. Although there are numerous studies to date analyzing HRM practices, none of them introduce methodologies that consider order or time factor within the management process of HR. This is the reason why 'path dependence' and 'cladistics' approaches are introduced in this doctoral thesis. 'Path dependence' approach shows how certain management decision taken at a certain point of time, influence future decisions. This makes it all the more essential to press ahead with analysis of where we come from and which path we have followed before being designed the future strategy of the organization. According to this approach, throughout this doctoral thesis, cladistics is used as methodology for analyzing organizations from a different perspective of people management compared to the habitual viewpoints. Cladistics is a methodology that can be used in the decision-making process; moreover, it allows identifying the expected result of implementing certain bundles of HRM practices, taking also into account HRM practices already implemented. It considers therefore, also prior organization history. This methodology, for the analysis and classification, has been commonly used in the field of biology for many years. Throughout this doctoral thesis, the transference of this methodology to HRM is shown. Biologist use Cladistics in order to build evolutionary maps termed as cladograms. Cladograms are graphic representations of animal species evolution. This methodology has already been used in fields other than biology, such as linguistics or astronomy among others. In management, it has not yet been developed sufficiently; in particular, the most relevant examples in this field are in operations management area. The purpose of this work is to extrapolate the basics of Cladistics to HRM field. In doing so, HRM practices have been analyzed, such as personnel selection, rewards systems, appraisal systems, training, etc¿ The bundle of HRM practices that certain organization has been implemented at certain point of time will determine what kind of organization is. Thus, a evolutionary map is built. It can be use as a benchmarking tool in order to analyze what sort of HRM practices has been implemented by competitors, haw far they have gone, and in what sort of organization have become. In this work, a simple example of evolution in time of Spanish manufacturing companies is shown. The organization growth in size (number of employees) has been considered as evolutionary factor. This is due to the fact that, as number of employees increase, HRM programs have to be different. Furthermore, a preliminary application of Cladistics is offered in hospitality sector. / [ES] La presente tesis estudia la evolución del sistema de gestión de recursos humanos en las organizaciones. Es decir, cambios introducidos a través de la gestión de personas. El objetivo principal de la tesis es analizar cómo las empresas van evolucionando y cambiando en el tiempo a través del capital humano. En los últimos años se ha demostrado que los niveles de adaptación y cambio que requieren las organizaciones para adaptarse a su entorno cambiante, son cada vez más elevados. Uno de los motores que facilitan este cambio organizacional, es la introducción de nuevos programas de gestión y herramientas que ayuden a las organizaciones a mejorar sus resultados empresariales. Este trabajo se centra en la identificación y análisis de estos programas en el ámbito de la gestión de RRHH. En particular: qué prácticas de RRHH se implementan, en qué tipo de empresas, en qué momento y, por último, en qué orden. Aunque ya existen numerosos estudios que analizan las prácticas de RRHH, hasta el momento, no existen herramientas que introduzcan el factor orden o tiempo en este proceso gestión de RRHH. Ésta es la causa por en esta tesis se utilizan los enfoques de 'path dependence' y 'cladistics'. El concepto de 'Path dependence', muestra cómo las decisiones de gestión que son tomadas en un momento determinado, influyen en las decisiones futuras. Este hecho hace que, antes de diseñar la estrategia a seguir en el futuro, se haya de analizar de dónde venimos y que camino se ha seguido para llegar hasta aquí. Bajo este enfoque, a lo largo de esta tesis, se utiliza la cladística como metodología de análisis de las organizaciones desde una perspectiva de gestión de personas diferente a las habituales en este ámbito. La Cladistica es una metodología que puede ser empleada como herramienta de toma de decisiones, y que permite identificar qué resultado se obtendría tras implantar un conjunto determinado de prácticas de gestión de RRHH, en función de las que ya se han implantado previamente (y por tanto de la historia previa de la organización). Esta metodología de análisis y clasificación ha sido comúnmente empleada en el ámbito de la biología y a lo largo de la presente tesis, se muestra cómo puede transferirse a la gestión de RRHH. Los biólogos, emplean la Cladística para la construcción de mapas evolutivos denominados cladogramas. Éstos son representaciones gráficas de la evolución de las especies animales. Si bien esta metodología se ha empleado ya en otros ámbitos diferentes a la biología, tales como la lingüística o la astronomía entre otros; en el área de management se ha desarrollado poco aún estando enmarcados los ejemplos más relevantes en el área de la gestión de operaciones. En este trabajo se extrapolan los conceptos básicos de la Cladistica al área de la gestión de recursos humanos. Para ello se estudian las prácticas de recursos humanos, tales como la selección de personal, sistemas de retribución, sistemas de evaluación, formación, etc¿ El tipo de prácticas de RRHH que ha seguido una determinada organización a lo largo del tiempo, es lo que determinará a qué tipo de organización pertenecen. Así, se construye un mapa evolutivo que puede emplearse como herramienta de benchmarking para ver qué practicas han implementado otros, dónde han llegado con ello y en qué tipo de organización se han convertido. En esta tesis se muestra un ejemplo sencillo de evolución en el tiempo de empresas en el sector manufacturero español, considerando como factor evolutivo el crecimiento en tamaño de organización (número de empleados). Entendiendo que, a medida que se incrementa el número de empleados, los programas de gestión de personas han de ser diferentes. Así mismo, se presenta una aplicación preliminar de la Cladistica al sector hospitality. / [CAT] Aquesta tesi estudia l'evolució del sistema de gestió de recursos humans a les organitzacions. És a dir, els canvis realitzats a través de la gestió de persones. L'objectiu principal de la tesi és analitzar com les empreses estan evolucionant i canviant en el temps a través de la capital humà. En els darrers anys s'ha demostrat que els nivells d'adaptació i canvi que requereixen les organitzacions a adaptar-se al seu entorn canviant, són cada cop més elevats. Un dels motors que facilita aquest canvi organitzacional és la introducció de nous programes de gestió i ferramentes que ajuden les organitzacions a millorar els seus resultats de negoci. Aquest treball es centra en la identificació i anàlisi d'aquests programes en l'àmbit de gestió de recursos humans. En particular: quines pràctiques RRHH estan implementades, a quin tipus d'empreses, quan i, finalment, en quin ordre. Encara que hi ha nombrosos estudis que analitzen les pràctiques RRHH, fins ara, no hi ha cap ferramenta que introdueixen el factor ordre o temps en aquest procés de gestió de recursos humans. Aquesta és la raó per la cual s'utilitzen en aquesta tesi els enfocaments de "dependència del camí' i 'cladística'. El concepte de "Path dependence", mostra com les decisions de gestió que es prenen en un moment donat, influencien les decisions futures. Això significa que, abans de dissenyar l'estratègia a seguir en el futur, cal analitzar d'on venim així com el camí que s'ha seguit per arribar fins ací. Davall este enfocament, al llarg d'esta tesi, s'utilitza la cladística com a metodologia d'anàlisi de les organitzacions des d'una perspectiva de gestió de persones diferent de les habituals en este àmbit. La Cladistica és una metodologia que pot ser empleada com a ferramenta de presa de decisions, i que permet identificar què resultat s'obtindria després d'implantar un conjunt determinat de pràctiques de gestió de RRHH, en funció de què ja s'han implantat prèviament (i per tant de la història prèvia de l'organització). Esta metodologia d'anàlisi i classificació ha sigut comunament empleada en l'àmbit de la biologia i al llarg de la present tesi, es mostra com pot transferir-se a la gestió de RRHH. Els biòlegs, usen la Cladística per a la construcció de mapes evolutius denominats cladogramas. Aquests són representacions gràfiques de l'evolució d'spècies animals. Si bé esta metodologia s'ha utilitzat ja en altres àmbits diferents de la biologia, com ara la lingüística o l'astronomia entre altres; en l'àrea de management s'ha desenvolupat poc encara, estant emmarcats els exemples més rellevants en l'àrea de la gestió d'operacions. En aquest treball s'extrapolen els conceptes bàsics de la Cladistica a l'àrea de la gestió de recursos humans. Per a això s'estudien les pràctiques de recursos humans, com ara la selecció de personal, sistemes de retribució, sistemes d'avaluació, formació, etc... Les pràctiques de recursos humans que ha seguit una organització particular al llarg del temps, és el que determinarà a quin tipus d'organització pertanyen. Així, es construïx un mapa evolutiu que es pot utilitzar com a ferramenta de benchmarking per a veure què practiques ha implementat la competnecia, a on han arribat amb això, i en quin tipus d'organització s'han convertit. A aquesta tesi es mostra un exemple senzill d'evolució en el temps d'empreses en el sector manufacturer espanyol, considerant com a factor evolutiu el creixement en grandària de l'organització (nombre d'empleats) . Entenent que, a mesura que s'incrementa el nombre d'empleats, els programes de gestió de persones han de ser diferents. Així mateix, es presenta una aplicació preliminar de la Cladistica al sector hospitality. / Perelló Marín, MR. (2015). Study of evolution in human resources management programs in organizations. Application of "Path Dependence" and "Cladistics" [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54110 / TESIS
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Hybridation et dynamique des populations chez les renouées du Japon: Espèces non-indigènes invasives du genre Fallopia Adans. (Polygonaceae) en Belgique / Hybridization and dynamics of populations of the Japanese knotweeds: Alien invasive species of the genus Fallopia (Polygonaceae) in Belgium

Tiébré, Marie-Solange 24 October 2007 (has links)
The Japanese knotweeds are invasive alien clonal species originating in Asia (Japan, Korea, Taiwan and Nord of China). They were introduced in Europe at the beginning of the 19th century. They are now some of the most troublesome invasive alien species in Europe and in the United States. In Belgium, a complex of four taxa and a hybrid represents them. All these taxa take part in the pattern of invasion and represent an excellent opportunity for studies of population biology in Western continental Europe. The presence from at least three taxa and a hybrid is confirmed by cytological, genetic and morphological studies. Vegetative reproduction is recognized as the main mode of reproduction and expansion of these taxa in the introduce range. However, interspecific hybridization events are observed confirming the restoration of the sexual reproduction by hybridization within this complex species in Belgium. Hybrid F. x bohemica with various ploidy levels from tetraploid to octoploid is observed. An increase in genotypic and morphological diversity is shown at the hybrid F. x bohemica which missed with the parental species. This could increase the potential of Japanese knotweeds to adapt to the new environment and contribute to the invasive success of these taxa in Belgium. Assignment test indicates a genetic pool differentiated at the hybrid F. x bohemica and not a mixture of the genetic pool of the parental species as expected for hybrid taxa. Hybrid F. x bohemica has always been considered as rare in Belgium and of horticultural origin. An analysis of the spatial distribution shows that hybrid F. x bohemica is widespread in Belgium and that its abundance depends on the areas. An analysis of extent of differentiation between groups of hybrid geographically distant could not provide proof of an independent evolution of hybrid populations under limited gene flow. An analysis of the sexual reproduction capacity and dispersal of seeds shows important production of viable seeds and consequent seed rain. Hybrid seeds may be dispersed beyond 16m, leading the possibility of founding new individuals and to contribute to the invasive success of these taxa. However, a trend towards decreasing germination rate is shown after a cold period. An analysis of the distribution at the landscape scale shows that the dynamics of colonization of habitats patches by Japanese knotweeds rising mainly from clonal propagation in spite of important pressure of propagule. The knotweeds prefer human disturbed habitats with a clear prevalence of communication routes. This leads the possibility of dispersing towards the adjacent habitats patches. A high dynamics of establishment of propagule was not observed at the hybrid plants compared with the parents plants in spite of the increase in genotypic diversity and the consequent pressure of propagule. Lastly, proposals for the integrated management of these taxa are proposed in the Belgium context. Their management will have first to identify hybrids and taxa involved. Emasculation and management of the existing clones represent solutions to prevent flowering and expansion of these taxa. An active management of disturbed habitats may represent alternative to prevent the invasion by Japanese knotweeds / Les renouées du Japon sont des espèces clonales non-indigènes originaires dAsie (Japon, Corée, Taiwan et Nord de la Chine). Elles ont été introduites en Europe au début du 19è siècle. Elles font désormais partie des espèces non-indigènes les plus invasives en Europe et aux Etats Unis. En Belgique, elles sont représentées par un complexe de quatre taxons et un hybride. Tous ces taxons participent à la dynamique dinvasion et représentent un modèle dintérêt pour les études de biologie des populations en Europe continentale occidentale. La présence dau moins trois taxons et un hybride est confirmée par des études cytologiques, génétiques et morphologiques. La reproduction végétative est reconnue comme le principal mode de reproduction et dexpansion de ces taxons dans la zone dintroduction. Toutefois, des phénomènes dhybridation interspécifique sont observés confirmant la restauration de la reproduction sexuée par hybridation au sein de ce complexe despèces en Belgique. Lhybride F. x bohemica avec différents niveaux de ploïdie, du tétraploïde à loctoploïde, est observé. Un accroissement de la diversité génotypique et morphologique qui manquait aux espèces parents est démontré chez lhybride F. x bohemica. Ceci pourrait augmenter le potentiel des renouées du Japon à sadapter au nouvel environnement et contribuer au succès invasif de ces taxons en Belgique. Un test dassignation indique un pool génétique différencié chez lhybride F. x bohemica et non un mélange du pool génétique des espèces parentales comme attendu dans le cadre de taxons hybrides. Lhybride F. x bohemica a toujours été considéré comme rare en Belgique et dorigine horticole. Une analyse de la répartition spatiale montre que lhybride F. x bohemica est très répandu en Belgique et que son abondance dépend des régions. Une analyse de létendue de la différenciation entre groupes dindividus hybrides géographiquement distants na pas pu fournir de preuve dune évolution indépendante des populations hybrides sous un flux de gènes limité. Une analyse de la capacité de reproduction sexuée et de dispersion des graines démontre une production importante de graines viables et une pluie de graines conséquente. Les graines hybrides sont capables de se disperser à plus de 16m, laissant la possibilité de fonder de nouveaux individus et de contribuer au succès invasif de ces taxons. Cependant, une tendance à la diminution du potentiel de germination est observée après une période de froid chez ces taxons. Une analyse de la distribution à léchelle du paysage a permis dinterpréter la dynamique de colonisation des taches dhabitats par les renouées du Japon comme relevant principalement de la propagation clonale malgré une pression de propagule importante. Les renouées du Japon préfèrent les habitats perturbés par lhomme avec une nette prédominance des réseaux linéaires de communications. Ceci laisse ensuite la possibilité de se disperser vers les taches dhabitats adjacents. Une dynamique détablissement de propagules plus importante na pas été observée chez les plants hybrides comparées aux plants parents malgré laccroissement de diversité génotypique et la pression de propagules considérable. Enfin, des pistes pour la gestion intégrée des renouées du Japon en Belgique sont proposées. Cette gestion devra en priorité identifier les hybrides et les taxons en présence. Des mesures démasculation et de gestion des clones existants pourraient constituer une solution pour empêcher la floraison et lexpansion de ces taxons. Une gestion active des habitats perturbés pourrait représenter une alternative pour prévenir linvasion par les renouées du Japon

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