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This article describes and analyses the present conditions of the application of the Public Work Tax Deduction (PWTD) mechanism, identifying six main obstacles that difficult on a appreciable way his concrete implementation or the rate of it.For this purpose, this study has identify and analyze the 30 main highlights that conform the critical path of PWTD process, determining the actual times for his performance and comparing them with the legal times established on the PWTD actual law, and so with the optimal times reasonably according with the experience on the public management of similar work projects. / El presente artículo describe y analiza las condiciones actuales de la aplicación delmecanismo de Obras por Impuestos (OXI), identificando seis obstáculos principales que dificultan de manera apreciable su implementación concreta o la velocidad de la misma. Para efectos del presente estudio se han identificado y analizado los principales 30 hitos que conforman la ruta crítica del proceso OXI, determinando los tiempos reales para su cumplimiento y comparándolos con los tiempos legales establecidos en la normativa OXI actual, y con los tiempos óptimos estimados razonablemente de acuerdo a la experiencia en la gestión pública de proyectos similares.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2013. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-10-09T18:20:31Z No. of bitstreams: 1 Guilherme.pdf: 821439 bytes, checksum: 3a414dc4e5f970b5be2493d535705751 (MD5) / Approved for entry into archive by Sabrina Andrade (sabrinabeatriz@ibest.com.br) on 2013-10-17T03:10:27Z (GMT) No. of bitstreams: 1 Guilherme.pdf: 821439 bytes, checksum: 3a414dc4e5f970b5be2493d535705751 (MD5) / Made available in DSpace on 2013-10-17T03:10:27Z (GMT). No. of bitstreams: 1 Guilherme.pdf: 821439 bytes, checksum: 3a414dc4e5f970b5be2493d535705751 (MD5) Previous issue date: 2013 / A ordem Phaethontiformes é composta por três espécies de aves marinhas, todas agrupadas no gênero Phaethon, as quais não possuem dimorfismo sexual aparente. No Brasil, P. aethereus e P. lepturus nidificam nos arquipélagos dos Abrolhos (BA) e de Fernando de Noronha (PE), e encontram-se na lista brasileira de espécies ameaçadas de extinção. Este trabalho teve como objetivos testar a existência de dimorfismo sexual de tamanho nessas duas espécies, gerar equações discriminantes para a determinação sexual com base em morfometria, verificar a variabilidade genética das populações de ambas as espécies, testar a ocorrência do efeito de gargalo populacional, e a conectividade intraespecífica entre as populações que nidificam nos dois arquipélagos estudados. Para a análise de dimorfismo sexual foram utilizadas oito variáveis morfométricas e realizada a determinação sexual pelo método molecular, para verificar diferenças intersexuais univariadas. A partir desses dados, foram ajustados modelos lineares generalizados, com o maior poder discriminatório possível. As informações genéticas foram obtidas através da amplificação e genotipagem de 11 loci de microssatélites, acessando índices de diversidade genética, distribuição das frequências alélicas, e grau de relação entre as populações dos dois arquipélagos. Para P. aethereus foi identificado dimorfismo sexual significativo em quatro variáveis, com machos maiores que fêmeas, e ajustado um modelo com 73,4% de poder discriminatório. Para P. lepturus, apenas a corda da asa apresentou diferença intersexual significativa, com fêmeas maiores que machos, e o melhor modelo ajustado discriminou corretamente 70,4% dos indivíduos. Esses resultados representam as primeiras informações sobre dimorfismo sexual na ordem Phaethontiformes. A heterozigosidade média foi baixa para ambas as espécies, o que pode ser explicada pelos altos índices de endocruzamento. Não foram identificados indícios de eventos de gargalo de garrafa recentes. Não há relação intraespecífica entre os arquipélagos estudados, indicando estruturação populacional de ambas as espécies na costa brasileira. Os resultados ressaltam a necessidade de medidas de conservação que considerem a distinção genética entre as populações de cada arquipélago, de ambas as espécies, bem como a necessidade de estudos que abordem outras questões, como parâmetros reprodutivos e análise filogeográfica, visando a sua conservação. / The order Phaethontiformes comprises three seabird species, all grouped in the genus Phaethon, which have no apparent sexual dimorphism. In Brazil, P. aethereus and P. lepturus nest on Abrolhos (BA) and Fernando de Noronha (PE) archipelagos, and are listed as threatened by the Brazilian red list. This study aimed to test the existence of sexual size dimorphism in these two species, to generate discriminant functions for sex determination based on morphometry, to verify genetic diversity of populations for both species, to test the occurrence of recent bottleneck events, and to check intraspecific connectivity for both species between the two archipelagos. For the analysis of sexual dimorphism were used seven morphometric variables and performed sex determination by molecular analysis, in order to verify univariate intersexual differences. From these data, generalized linear models were fitted with the highest discriminatory power. Genetic data were obtained by amplification and genotyping of 11 microsatellite loci, accessing genetic diversity indices, distribution of allelic frequencies, and degree of relationship between populations of the two archipelagos. Males were larger in P. aethereus, significant for four variables, and fitted a model with 73.4% of discriminatory power. For P. lepturus only wing chord showed significant intersexual difference, with females larger than males, and the best fitted model correctly discriminated 70.4% of individuals. Such results represent the first information on sexual dimorphism in the order Phaethontiformes. Average heterozygosity was low for both species, which could to be explained by high levels of inbreeding. There was no evidence of recent bottleneck events in both species, as well as no intraspecific relationship between archipelagos studied, indicating genetic structuring for both species on the Brazilian coast. These findings highlight that conservation measures need to take into account the genetic distinctiveness of populations nesting in each island, for both species, as well as the need of studies that address other issues such as breeding parameters and phylogeographic analysis.

Abstract Many species and populations have perished as a consequence of human actions. During the last ~200 years, large carnivores have been almost completely extirpated from Western Europe. Large-scale wolf hunting started in Finland around the 1850s, and the population size quickly collapsed. The population was very small until the mid-1990s, when wolves started to regularly reproduce in Finland again. The wolf is an endangered species in Finland, and the biggest threat to the species’ survival is excessive hunting. In this doctoral thesis study, I inspected the genetic structure and diversity of the Finnish wolf population using neutral genetic markers. Almost 300 wolves from the contemporary Finnish population and over 50 wolves from the north-western Russia were analyzed with genetic methods. Additionally, the genetic history of the population was examined with the help of over 100 museum samples. The modern Finnish wolf population proved to be genetically as diverse as the non-endangered Eastern European and North American wolf populations. However, the genetic diversity decreased significantly during the study period (1995–2009), and was at its lowest level in the final phase of the examination. In tandem, the inbreeding coefficient rose to a relatively high level. Genetic sub-structures were observed due to social structures within wolf packs. The mean dispersal distances of wolves were approximately only 100 km. The Finnish wolf population is divided into neighbourhoods of related individuals, and their size substantially decreased during the study period. This pattern, together with the growth of the inbreeding coefficient, suggests that lost alpha individuals in wolf packs are replaced by their offspring. This study demonstrated that Russian and Finnish wolf populations are nowadays genetically differentiated. Gene flow between the populations is low, despite the geographic interconnection. Only a few possible immigrants from Russia into Finland were detected in the study. The effective size of the Finnish wolf population proved to be small, and was mainly below the often-considered critical size of 50. Historical analysis revealed that the Finnish wolf population was formerly genetically more diverse, more continuous with the Russian wolf population, and had a more than 90% larger effective size. On the basis of this study, the genetic status of the Finnish wolf population is worrying and needs to be monitored. The population should be substantially larger than today and/or the amount of gene flow higher, so that the population viability could be considered secured even in the short term. / Tiivistelmä Ihmisen toiminnan seurauksena lukuisat eliölajit ja –populaatiot ovat hävinneet. Viimeisten noin 200 vuoden aikana suurpedot hävitettiin lähes koko Länsi-Euroopasta. Laajamittainen sudenmetsästys alkoi Suomessa 1850-luvun paikkeilla ja kanta romahti nopeasti. Populaatio oli hyvin pieni lähes koko 1900-luvun, ja sudet ovat jälleen lisääntyneet yhtäjaksoisesti Suomessa vasta 1990-luvun puolivälistä. Susi on erittäin uhanalainen Suomessa ja merkittävin uhka lajin säilymiselle on liiallinen metsästys. Tarkastelen tässä väitöskirjatyössäni Suomen susipopulaation geneettistä rakennetta ja monimuotoisuutta neutraaleja geenimerkkejä käyttäen. Tutkimuksessa analysoitiin geneettisin menetelmin lähes 300 sutta nyky-Suomesta sekä yli 50 sutta Luoteis-Venäjältä. Lisäksi populaation geneettistä historiaa selvitettiin yli 100 museonäytteen avulla. Nykyinen Suomen susipopulaatio osoittautui tutkimuksessa geneettisesti yhtä monimuotoiseksi kuin ei-uhanalaiset susipopulaatiot Itä-Euroopassa ja Pohjois-Amerikassa. Geneettisen muuntelun määrä kuitenkin laski tutkimusajanjaksolla (1995–2009) merkitsevästi ollen matalin tarkastelujakson lopussa. Samanaikaisesti populaation sukusiitoskerroin nousi verrattain korkeaksi. Susipopulaatiossa havaittiin sosiaalisista rakenteista johtuvia geneettisiä alarakenteita. Susien dispersaalimatkat olivat keskimäärin vain noin 100 km. Suomen susipopulaatio on jakautunut toisilleen sukua olevien yksilöiden naapurustoiksi, joiden koko pieneni huomattavasti tutkimusajanjaksolla. Tämä yhdessä sukusiitoskertoimen kasvun kanssa viittaa susilaumojen menetettyjen alfayksilöiden korvautumiseen jälkeläisillään. Tutkimus osoitti, että Venäjän ja Suomen susipopulaatiot ovat nykyisin geneettisesti erilaistuneet. Geenivirta populaatioiden välillä on maantieteellisestä yhteydestä huolimatta vähäistä. Tutkimuksessa havaittiin vain muutamia todennäköisiä immigrantteja Venäjältä Suomeen. Suomen susipopulaation efektiivinen koko osoittautui pieneksi ollen pääosin alle kriittisenä rajana pidetyn 50:en. Historiallinen tarkastelu osoitti Suomen susipopulaation olleen aiemmin geneettisesti monimuotoisempi, yhtenäisempi Venäjän susipopulaation kanssa ja efektiiviseltä kooltaan yli 90 % nykyistä suurempi. Tutkimuksen perusteella Suomen susipopulaation geneettinen tila on huolestuttava ja tarvitsee seurantaa. Populaation tulisi olla nykyistä huomattavasti suurempi ja/tai geenivirran määrän korkeampi, jotta populaation elinvoimaisuuden voitaisiin katsoa olevan turvattu edes lyhyellä aikavälillä.

Abstract Spatial and temporal variation is a universal feature in most organisms in nature, commonly reflecting the past evolutionary history of the species as well as the prevailing environmental conditions. The purpose of this doctoral thesis study was to investigate the genetic and phenotypic variation, and to assess the roles of the different processes affecting them in the moose (Alces alces). Altogether 809 DNA samples of moose, gathered throughout Finland and the Republic of Karelia in Russia, were analysed with a variety of population genetic methods. Furthermore, the shape of the moose mandible was investigated with the help of geometric morphometrics using a subset of samples gathered from 179 moose in Finland. This study showed that the Finnish and especially the Karelian moose population harboured relatively high genetic diversity, albeit with clear regional differences in its spatial distribution. In the northern half of Finland, a secondary contact of two diverged mitochondrial lineages was revealed. The presence of the two lineages was interpreted to reflect the existence of allopatric refugia of moose during the Last Glacial Maximum and the subsequent bi-directional recolonisation of Fennoscandia. Furthermore, a spatially explicit Bayesian clustering analysis suggested existence of three genetic clusters, which were estimated to have split after the post-glacial recolonisation. The results also showed that past declines in the moose numbers during the 18th and 19th centuries led to population bottlenecks, leaving a genetic imprint. Thus, the present moose population in eastern Fennoscandia carries the signs of both ancient and more recent events in its genetic composition. Finally, a significant latitudinal shift was revealed in the shape of the moose mandible. The pattern was considered independent of the genetic clustering of the population. The main changes included an enlargement of the attachment surfaces of the muscles controlling biting and mastication, implying more effective mastication in the north compared with the south, possibly an adaptive response to a longer period of hard wintertime diet. The results of this thesis encourage continuation of studies on the moose in order to fully reveal the impact of particular historical events and especially anthropogenic factors on the genetic and phenotypic variation of this species. They also provide the starting point for ‘genetically enlightened’ moose management and conservation in Finland. / Tiivistelmä Lähes kaikilla eliölajeilla esiintyy ajallista ja paikallista muuntelua, joka on seurausta lajin evolutiivisesta historiasta ja vallitsevista ympäristöoloista. Tässä väitöskirjatutkimuksessa tutkin hirven (Alces alces) geneettistä ja fenotyyppistä muuntelua sekä niitä selittäviä taustatekijöitä populaatiogeneettisillä ja geometrisen morfometrian menetelmillä. Geneettisen aineiston muodostivat Suomesta ja Venäjän Karjalasta kerätyt 809 hirven DNA-näytteet. Fenotyyppisenä ominaisuutena tutkittiin hirven leukaluun muotoa yhteensä 179 alaleuasta. Geneettinen monimuotoisuus oli tutkimuksen mukaan Suomen ja erityisesti Karjalan hirvipopulaatiossa verrattain korkea, joskin alueelliset erot olivat varsin selviä. Pohjoisesta Suomesta löytyi kahta erilaistunutta mitokondrion DNA:n sukulinjaa, joiden arvioin erilaistuneen viimeisen jääkauden aikana, todennäköisesti erillisissä refugioissa, ja saapuneen aikoinaan Suomeen eri reittejä pitkin. Tämän ohella tuman DNA paljasti lisää alueellisia rakenteita; bayesilainen ryhmittelyanalyysi havaitsi hirvellä kolme erillistä alapopulaatiota. Näiden ryhmien arvioin kehittyneen vasta Suomen uudelleenasuttamisen jälkeen. Tämän tutkimuksen tulokset osoittivat myös, että historiallisesti tunnetut kannanromahdukset 1700- ja 1800-luvuilla johtivat populaation pullonkaulaan, joka jätti jälkensä hirven perimään. Itäisen Fennoskandian hirvipopulaation geneettiseen muunteluun ovat siis vaikuttaneet sen historian aikana niin jääkauden aikaiset kuin tuoreemmatkin tapahtumat. Tämän lisäksi hirven alaleuan muodossa havaittiin merkitsevä etelä-pohjoissuuntainen muutos. Tulosten mukaan purentaa ohjaavien lihasten kiinnityspinnat laajenevat pohjoista kohti siirryttäessä, mikä viittaisi siihen, että hirven leukojen puruvoima on pohjoisessa suurempi kuin etelässä. Ilmiö oli riippumaton populaation geneettisestä ryhmittyneisyydestä, ja se on mahdollisesti seurausta kovemman talviruokavalion aiheuttamasta adaptiivisesta vasteesta. Tämän väitöskirjan tulokset rohkaisevat jatkamaan aiheen tutkimusta, jotta eri historiallisten tapahtumien sekä eritoten ihmisvaikutuksen merkitys lajin geneettiseen ja fenotyyppiseen muunteluun voitaisiin selvittää perin pohjin. Lisäksi tulokset muodostavat lähtökohdan ’geneettisesti valistuneelle’ hirvikannan hoidolle Suomessa.

The topic of this thesis is to optimize the production process of ferrite cores in the company Epcos, Ltd. The work is divided into theoretical, analytical and design part. The first part of the thesis contains theoretical knowledge within the field of lean manufacturing, process mapping and mapping value streams. Based on these findings is determined the theoretical basis for the processing of other parts of the thesis. The aim of the analytical part of the analysis is to map the current state of the manufacturing process, finding bottlenecks, evaluating the results of analysis of the current state, which will be used for the design part of the thesis, to develop proposals for optimizing production bottlenecks and evaluate their contribution.

Variable Speed Limit (VSL) strategies identify and disseminate dynamic speed limits that are determined to be appropriate based on prevailing traffic conditions, road surface conditions, and weather conditions. This dissertation develops and evaluates a shockwave-based VSL system that uses a heuristic switching logic-based controller with specified thresholds of prevailing traffic flow conditions. The system aims to improve operations and mobility at critical bottlenecks. Before traffic breakdown occurrence, the proposed VSL’s goal is to prevent or postpone breakdown by decreasing the inflow and achieving uniform distribution in speed and flow. After breakdown occurrence, the VSL system aims to dampen traffic congestion by reducing the inflow traffic to the congested area and increasing the bottleneck capacity by deactivating the VSL at the head of the congested area. The shockwave-based VSL system pushes the VSL location upstream as the congested area propagates upstream. In addition to testing the system using infrastructure detector-based data, this dissertation investigates the use of Connected Vehicle trajectory data as input to the shockwave-based VSL system performance. Since the field Connected Vehicle data are not available, as part of this research, Vehicle-to-Infrastructure communication is modeled in the microscopic simulation to obtain individual vehicle trajectories. In this system, wavelet transform is used to analyze aggregated individual vehicles’ speed data to determine the locations of congestion. The currently recommended calibration procedures of simulation models are generally based on the capacity, volume and system-performance values and do not specifically examine traffic breakdown characteristics. However, since the proposed VSL strategies are countermeasures to the impacts of breakdown conditions, considering breakdown characteristics in the calibration procedure is important to have a reliable assessment. Several enhancements were proposed in this study to account for the breakdown characteristics at bottleneck locations in the calibration process. In this dissertation, performance of shockwave-based VSL is compared to VSL systems with different fixed VSL message sign locations utilizing the calibrated microscopic model. The results show that shockwave-based VSL outperforms fixed-location VSL systems, and it can considerably decrease the maximum back of queue and duration of breakdown while increasing the average speed during breakdown.

Les îles du Sud-Ouest de l'océan Indien (SOOI) abritent une faune et une flore exceptionnelle et constituent l'un des cinq hotspot de biodiversité les plus importants au monde. L'abeille domestique Apis mellifera occupe divers habitats dans la majorité de ces îles et interagit avec une flore indigène et endémique. Elle est également exploitée par l'Homme pour l'apiculture. A. mellifera a divergé en plusieurs lignées évolutives et sous-espèces dans son aire d'origine. Parmi-elles, A. m. unicolor a été décrite comme endémique de Madagascar et appartient à la lignée africaine A. Les objectifs de cette thèse étaient de caractériser l'abeille dans les archipels des Mascareignes, Comores et Seychelles en identifiant les lignées évolutives et sous-espèces présentes avec des marqueurs mitochondriaux (région intergénique COI-COII, gène ND2). Dans un second temps, une étude de la diversité et de la structure génétique a été réalisée sur ces mêmes populations insulaires (15 microsatellites). Un total de 4095 colonies ont été échantillonnées dans le SOOI et 238 dans l'aire naturelle continentale. Trois des quatre lignées évolutives (A, C et M) ont été détectées dans les 10 îles étudiées et ce en différentes proportions. La lignée africaine A et A. m. unicolor sont prépondérantes dans le SOOI excepté à Rodrigues (100% lignée européenne C). Dans toutes les îles de l'archipel des Comores et des Seychelles, 100% des colonies échantillonnées appartiennent à la lignée A, 95,2% à La Réunion et seulement 54,2% à Maurice. Les îles de l'archipel des Comores constitueraient une zone de contact entre la lignée africaine continentale et les populations d'A. m. unicolor. La diversité génétique nucléaire est forte dans les archipels du SOOI et est structurée par îles et archipels. En outre, les populations du SOOI se différencient fortement des populations continentales africaines et européennes. La combinaison des différents marqueurs privilégie l'hypothèse d'une colonisation ancienne et naturelle d'A. m. unicolor depuis Madagascar à La Réunion, Maurice et aux Seychelles. / The South West Indian Ocean (SWIO) islands are home to an exceptional flora and fauna and are considered as one the five most important biodiversity hotspots in the world. In most islands of this region, the honeybee Apis mellifera occupies diverse habitats. Regarding its ability as a generalist pollinator, honeybee interacts with native and highly endemic flora. Furthermore, this species is used by human for beekeeping as it is able to produce honey, pollen and other hive products. Within the large group of bees (Apidae), A. mellifera is a model of diversity that has diverged into several lineages and subspecies in its native range. Among the 28 recognized subspecies, A. m. unicolor has been described as endemic to Madagascar and belongs to the African A lineage. The Mascarenes, Comoros and Seychelles archipelagos surround this continental island but the A. mellifera populations present have been little or never studied. The aims of this thesis were to characterize the honeybee from the Mascarenes (La Réunion, Mauritius, Rodrigues), Comoros (Anjouan, Mohéli, Grande Comore, Mayotte) and Seychelles (Mahé, Praslin, La Digue) archipelagos by determining the evolutionary lineages and subspecies present. Secondly, a study of genetic diversity and structure were conducted on these same insular populations. For that, a large sampling was carried (n = 4095 colonies from the SWIO, and 238 from native continental areas) and was combined to molecular analyzes using mitochondrial markers (sequencing of the COI-COII intergenic region and ND2 gene) and nuclear markers (15 microsatellite loci). Three of the four evolutionary lineages (A, C and M) were detected in different proportions in the 10 studied islands. The African A lineage and A. m. unicolor subspecies were predominant in the SWIO excepted for Rodrigues exclusively from the European C lineage. All sampled colonies from the Seychelles and Comoros archipelagos belong to the African lineage while in La Réunion the proportion reach 95.2% and only 54.2% in Mauritius. The presence of the Z African sub-lineage has been described for the first time out of Africa in two Seychelles islands. Moreover, Comoros islands may constitute a contact area between the continental African lineage and A. m. unicolor populations (insular African lineage). The SWIO populations show high levels of nuclear genetic diversity and a structuration by island and archipelago. In addition, SWIO populations strongly differentiated from African and European continental populations. The combined results from different molecular markers favor the hypothesis of an ancient and natural colonization from Madagascar to La Réunion, Mauritius and Seychelles islands. Therefore, the previous referenced interactions between the honeybee and the endemic fauna and flora in the SWIO might be explained by a long cohabitation in addition to its generalist pollinator ability.

Cette thèse porte un regard évolutif sur les invasions biologiques qui sont une menace écologique, économique et sanitaire grandissante.Qu'ils en soient la cause ou la conséquence, les invasions sont en effet le théâtre de changements évolutifs rapides et importants.Ces changements peuvent être liés à une différence de pression de sélection entre l'aire d'origine et l'aire envahie, mais peuvent aussi être initiés par des évènements démo-génétiques comme un goulot d'étranglement démographique ou l'admixture (hybridation intra-spécifique) entre populations génétiquement différentes.Les changements évolutifs concernent aussi bien des traits d'histoire de vie liés à la reproduction que le fardeau génétique et la dépression de consanguinité.La forte dérive génétique qui peut se produire au cours d'un goulot d'étranglement peut conduire à la purge ou la fixation rapide d'allèles délétères responsables du fardeau génétique.Les trais de reproduction peuvent eux aussi influencer directement l'issue d'une invasion, au travers du taux d'accroissement démographique de la population.Ils peuvent aussi avoir un effet indirect sur le succès d'introduction en modifiant l'intensité des effets des évènements démo-génétiques.Au cours de cette thèse, j'ai étudié l'évolution du fardeau génétique et de traits de reproduction au cours d'une invasion biologique grâce à (i) une série d'expériences sur l'espèce envahissante modèle Harmonia axyridis (la coccinelle asiatique) et à (ii) un modèle théorique de dynamique de la fréquence d'un allèle délétère dans une population subissant un goulot d'étranglement.Mes résultats montrent que les populations envahissantes ont des traits de reproduction plus performants que celles de l'aire native.En particulier, les femelles envahissantes présentent une fécondité plus élevée et fécondent leurs œufs avec le sperme d'un plus grand nombre de mâles.Il n'existe pas, chez cette espèce, de mécanisme évident d'évitement de la consanguinité, bien que les populations de l'aire native souffrent de dépression de consanguinité contrairement à celles de l'aire envahie.La dépression de consanguinité peut évoluer très vite chez cette espèce en cas de fort goulot d'étranglement.Dans les conditions expérimentales, les allèles délétères étaient parfois purgés, mais ont souvent été fixés dans la population au cours d'un goulot.Enfin, le modèle théorique a montré que les probabilités de perte ou de fixation d'un allèle délétère récessif peuvent toutes deux augmenter rapidement par dérive au cours d'un goulot d'étranglement d'intensité modérée.Ces résultats soulignent l'importance du hasard sur le succès d'une invasion biologique.Puisque la probabilité d'émergence de combinaisons génomiques favorables à l'invasion augmente avec le nombre d'introduction, limiter le nombre d'évènements d'introduction peut s'avérer déterminant pour prévenir de futures invasions biologiques. / This thesis provides some evolutionary insights on biological invasions, which represent a growing threat on ecology, economy and public health.Biological invasions are a place of rapid and important evolutionary changes that can be the cause or the consequence of invasion success.These changes can be caused by differences in selective pressures between the native and the invaded area.They can also be due to demo-genetic events such as demographic bottlenecks and admixture (emph{i.e.} intra-specific hybridisation) between genetically distinct populations.Evolutionary changes affect life-history traits (including reproductive traits) as well as the genetic load and inbreeding depression.Genetic drift can be strong during a bottleneck and can induce the rapid purging or fixation of deleterious alleles responsible for the genetic load.Reproductive traits can also influence the fate of an invasion by changing the demographic growth rate.Moreover, they can have an indirect impact on the success of introduction by altering the intensity of demo-genetic events.Throughout this thesis, I studied the evolution of the genetic load and of reproductive traits by the mean of (i) laboratory experiments using the invasive Harlequin ladybird Harmonia axyridis as a model species and (ii) through the study of a theoretical model of the dynamics of allele frequencies during a bottleneck.My results show that invasive populations have better reproductive traits than those from the native area.Particularily, invasive females display an increased fecundity and fertilize their eggs with the sperm of a higher number of males.In this species, there is no obvious mechanism of inbreeding avoidance, even though native populations suffer to inbreeding depression contrarily to invasive ones.Inbreeding depression can evolve quickly in this species if the population goes through a severe bottleneck.In my experiments, deleterious alleles were often fixed in the population during the bottleneck, but were sometimes purged.Finally, the theoretical model studied described show that the probability of complete loss or fixation of a deleterious recessive allele can both increase by drift during a bottleneck.These results highlight the importance of chance on the success of a biological invasion.Because the probability of emergence of genomic combinations that can favour an invasion increases with the number of introduction events, limiting the number of introduction events might be an efficient way to prevent or minimise upcoming biological invasions.

As alterações que a ação antrópica vem causando nos ambientes costeiros tem provocado impactos sobre as espécies a eles associadas. Larus dominicanus é uma espécie de ave marinha amplamente distribuída ao longo do Hemisfério Sul. Por possuir um hábito alimentar generalista, os resíduos da ação antrópica tem beneficiado a espécie, que, assim como outras gaivotas, vem apresentando um crescimento demográfico acelerado. O presente estudo, através do uso de marcadores de microssatélites, mostra que, apesar disso, a espécie possui uma baixa variabilidade genética, com fraca estruturação populacional, que provavelmente são o reflexo da origem recente da espécie e de uma diferenciação recente entre as populações. Múltiplas forças atuam para determinar a estruturação populacional, sendo elas o isolamento por distância, as barreiras físicas e a filopatria. Os sinais de gargalo populacional encontrados em algumas das colônias levantam a possibilidade de efeitos fundadores por colonização recente nas colônias mais ao norte da costa brasileira e redução populacional nas colônias da Argentina e da Antártica como conseqüência da última glaciação. Estes dados chamam a atenção para a necessidade de considerar as informações genéticas para a implantação de planos de manejo. Uma vez que a diferenciação entre as populações é recente, a variabilidade dentro de cada uma delas deve ser mantida. O controle populacional da espécie através de métodos diretos deve ser também acompanhado por planos de manejo ambiental, visando reduzir ou eliminar as condições que propiciam o crescimento desequilibrado dos gaivotões. / The changes in the coast that has been caused by human action has led to impacts on species associated with this environment. Larus dominicanus is a seabird species widely distributed throughout the Southern Hemisphere. The generalist feeding habits allow this species take advantage from human action, leading to population growth, which is also observed in other species of gulls. This study, through the use of microsatellite markers, shows that, despite of the population growth, Larus dominicanus has a low genetic variability, with low population structure, which probably reflects the recent origin of species and a recent differentiation among populations. Multiple forces act to determine the population structure, among them the isolation by distance, physical barriers and philopatry. Some colonies presents a bottleneck sign, raising the hypothesis of recent founder effects in the colonies to the north of Brazil and population reduction of colonies of Argentine and Antarctic as consequence of the last glaciation. These data show the need to consider genetic information for the implementation of management plans. The variability within populations must be maintained, since the differentiation between them is recent. Furthermore, the species population control by direct methods must also be accompanied by environmental management plans, to reduce or eliminate the conditions that favor the unbalanced growth of the gulls