Highway roughness is a concern for both the motoring public and highway authorities. Roughness may even increase the risk of crashes. Rail-highway grade crossings are particularly problematic. Roughness may be due to deterioration or simply due to the way the crossing was built to accommodate grade change, local utilities, or rail elevation. With over 216,000 crossings in the US, maintenance is a vast undertaking. While methods are available to quantify highway roughness, no method exists to quantitatively assess the condition of rail crossings. Conventional inspection relies on a labor-intensive process of qualitative judgment. A quantifiable, objective and extensible procedure for rating and prioritizing improvement of crossings is thus desired. In this dissertation, a 3D infrastructure condition assessment model is developed for evaluating the condition and performance of rail highway grade crossings. Various scanning techniques and devices are developed or used to obtain the 3D “point cloud” or surface as the first step towards quantifying crossing roughness. Next, a technique for repeatable field measurement of acceleration is presented and tested to provide a condition index. Acceleration-based metrics are developed, and these can be used to rate and compare crossings for improvement programs to mitigate potential vehicle damage and provide passenger comfort. A vehicle dynamic model is next customized to use surface models to estimate vertical accelerations eliminating the need for field data collection. Following, crossing roughness and rideability is estimated directly from 3D point clouds. This allows isolation of acceleration components derived from the surface condition and original design profile. Finally, a practice ready application of the 3D point cloud is developed and presented to address hump crossing safety. In conclusion, the dissertation presents several methods to assess the condition and performance of rail crossings. It provides quantitative metrics that can be used to evaluate designs and construction methods, and efficiently implement cost effective improvement programs. The metrics provide a technique to measure and monitor system assets over time, and can be extended to other infrastructure components such as pavements and bridges.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The focus of this dissertation is the examination of the relationship between space and identity in recent narratives of migration, in contemporary African literature. Migrant narratives suggest that there is a correlation between identity formation and the types of boundaries and borders migrants engage with in their various attempts to find new homes away from their old ones. Be it voluntary or involuntary, the process of migrating from a familial place transforms the individual who has to negotiate new social formations; and tensions often accrue from the confrontation between one’s culture and the culture of the receiving society. Return migration to the supposed country of origin is an equally important trajectory dealt with in African migrant literature. The reverse narrative stipulates similar tensions between one’s diasporic culture – the culture of the diasporic space – and the culture of the homeland. Thus, intra- and inter-continental migrations and diaspora is a bifurcated inquiry that examines both outward and return migrations. These movements reveal the ways in which Africans make sense of their Africanity and their place in the world. The concepts of “border”, “boundary” and “borderland” are useful to examine notions of difference and separation both within the nation-state and in relation to transnational, intra-African as well as inter-continental exchanges. I focus more fully on these notions in the texts that examine migrations within Africa, both outward and return movements. This study is not only interested in the physical features of borders, boundaries or borderlands, but also on their consequences for the processes of identity formation and translation, and how they can help to reveal the social and historical characteristics of diasporic formations. What undergirds much of the analysis is the assumption that the negotiation of belonging and space cannot be separated from the crossing or breaching of borders and boundaries; and that these negotiations entail attempts to enter the borderland, which is a zone of exchange, crisscrossing networks, dissolution of notions of singularity and exclusive identities. / AFRIKAANSE OPSOMMING: Die fokus van hierdie proefskrif is ‘n ondersoek na die verhouding tussen ruimte en identiteit in onlangse migrasie-narratiewe in kontemporêre Afrika-literatuur. Migrasienarratiewe dui op ’n korrelasie tussen identiteitsvorming en die soorte skeidings en grense waarmee migrante gemoeid raak in hulle onderskeie pogings om nuwe tuistes weg van die oues te vind. Hetsy willekeurig of gedwonge, die migrasieproses weg van ’n familiale plek verander die individu wat nuwe sosiale formasies moet oorkom, en spanning neem dikwels toe weens die konfrontasie tussen die eie kultuur en dié van die ontvangersamelewing. Migrasie terug na die sogenaamde land van herkoms is net so ’n belangrike onderwerp in Afrika-migrasieliteratuur. Die terugkeernarratief stipuleer dat daar ooreenkomstige spanning heers tussen ’n persoon se diasporiese kultuur – die kultuur van die diaspora-ruimte – en die kultuur van die land van oorsprong. Die ondersoek na intra- en interkontinentale migrasies en diasporas is dus ’n tweeledige proses wat uitwaartse sowel as terugkerende migrasies beskou. Hierdie bewegings openbaar die ware maniere waarop Afrikane sin maak uit hulle Afrikaniteit en hulle plek in die wêreld. Die konsepte van “grens”, “grenslyn” en “grensgebied” is nuttig wanneer die begrippe van verskil en verwydering ondersoek word binne die nasiestaat asook in verhouding tot transnasionale, intra-Afrika en interkontinentale wisseling. Ek fokus meer volledig op hierdie begrippe in die tekste wat ondersoek instel na migrasie binne Afrika, beide uitwaartse en terugkerende bewegings. Hierdie studie gaan nie net oor die fisiese kenmerke van grense, grenslyne en grensgebiede nie, maar bestudeer ook die gevolge daarvan op die prosesse van identiteitsvorming en vertaling, en die manier waarop hulle kan help om die sosiale en historiese eienskappe van diasporiese formasies te openbaar. ’n Groot deel van die analise word ondersteun deur die aanname dat die onderhandeling tussen tuishoort en ruimte nie geskei kan word van die oorsteek of deurbreek van grense en grenslyne nie, en dat hierdie onderhandelinge lei tot pogings om die grensgebied te betree, waar die grensgebied gekenmerk word deur wisseling, kruising van netwerke en die verwording van begrippe soos sonderlingheid en eksklusiewe identiteite.

<p>Istraživanje koje je sprovedeno u okviru disertacije poslužilo je za definisanje matematičkog modela koji se može primeniti u postupku određivanja nivoa usluge za nesignalisane pešačke prelaze. Formirani model za proračun stepena propuštanja pešaka u uslovima lokalnog odvijanja saobraćaja zavisi od protoka pešaka i vozila, strukture saobraćajnog toka (učešće autobusa i teretnih vozila) i smera kretanja vozila na lokaciji pešačkog prelaza. U okviru disertacije izvršena je analiza pešačkih intervala prilikom prelaska kolovoza. Uporednom analizom prihvatljivih i kritičnih intervala dobijen je model ponašanja pešaka u zavisnosti od karakteristika lokacije nesignalisanog pešačkog prelaza. Utvrđena je zavisnost između dužine prihvaćenih intervala pešaka prilikom prelaska kolovoza i uslova odvijanja saobraćaja, polnih karakteristika pešaka i broja pešaka koji prelaze kolovoz na nesignalisanom pešačkom prelazu.</p> / <p>The study, which was conducted within the thesis, has served to define a mathematical model that can be applied in the process of determining the level of service at unsignalized pedestrian crossings. The formed model for motorist yield rate, in terms of the local pedestrian traffic flow, depends on pedestrian and vehicular flow rate, traffic flow structure (the share of buses and freight vehicles), and vehicle moving at the location of a pedestrian crossing. The pedestrian gap acceptance behaviour has also been analysed. Comparative analysis of acceptable and critical pedestrian gap was conducted. Model of pedestrian behaviour, which depending on the site characteristics, was formed and it has been proven a correlation between the length of the accepted pedestrian gaps and the roadway and traffic conditions, gender characteristics and the number of pedestrians at unsignalized crossings.</p>

La version intégrale de ce mémoire est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l'Université de Montréal (www.bib.umontreal.ca/MU). / Dans mon travail de recherche et de création musicale, je m’inspire du concept d’intersection pour sa capacité à donner naissance à quelque chose de nouveau. Ce mémoire de maîtrise documente une exploration de ce concept dans trois contextes différents : une pièce instrumentale, une pièce mixte et une pièce pour chœur. J’emploie le mot « intersection » dans le sens figuré de deux éléments abstraits ou concrets qui se rencontrent. La nature de leur rencontre ainsi que les résultats possibles m’intéressent également. Je vise l’intégration du concept à tous les niveaux d’une pièce : du global (la conception, la forme) jusqu’au local (la facture et l’emploi des techniques de composition). Le choix de procédés est très ouvert et dépend entièrement du contexte de la pièce et du résultat artistique envisagé. Ainsi, dans chacune de mes trois pièces de maîtrise, j’ai choisi une approche différente de l’idée de l’intersection. J’ai expérimenté une variété de moyens et de procédés, ainsi que la fonction de la composante extra-musicale (lorsqu’il y en a une). Au premier chapitre, je discute de mon quintette Finding Common Ground qui explore l’intersection de l’écriture pour percussion avec l’écriture pour les quatre autres instruments plutôt « mélodiques ». Ensuite, au deuxième chapitre je présente ma pièce Pleine lune pour contrebasse et bande, qui apprivoise le croisement de l’écriture instrumentale avec l’écriture acousmatique. Finalement, au troisième chapitre j’expose ma pièce Séjour dans un autre monde, pour chœur de jeunes et piano préparé, qui s’inspire du croisement de la pensée électroacoustique et de l’écriture vocale et instrumentale. / In my musical research and creative work, I am inspired by the concept of intersection for its capacity to give birth to something new. This Master’s thesis documents an exploration of this concept in three different contexts: an instrumental piece, a mixed piece and a piece for choir. I employ the term “intersection” in the figurative sense of two elements, either abstract or concrete, which meet. The nature of their meeting and the possible results are of equal interest to me. I strive to integrate the concept at all levels of a piece: from the global perspective (the conception, the form) to the local perspective (the craft and the use of compositional techniques). The choice of procedures is wide open and depends entirely on the piece and the envisioned artistic result. Thereby, for each of my three Master’s pieces I chose a different approach to the concept of intersection. I experimented with a variety of means and procedures, as well as the function of the extra musical component (where applicable). In the first chapter, I discuss my quintet Finding Common Ground, which explores the intersection of percussion writing with the writing for the four other “melodic” instruments. Next, in the second chapter I present my piece Pleine lune for double bass and tape, which undertakes the crossing of instrumental writing with acousmatic writing. Finally, in the third chapter I examine my piece Séjour dans un autre monde, for youth choir and prepared piano, which was inspired by the crossing of electroacoustic thought with vocal and instrumental writing.

The present essay set out to investigate the work methodology of closing level crossings and chart the process from the initial need to close the level crossing up to completed closing of level crossing, furthermore; to investigate which factors affect the projects efficiency and progress both in terms of planning and implementation. This essay sets out to answer the following questions: “What is the current way of dealing with closing off level crossings and when would the implementation of a railway plan be useful?” and “How does project-implementation look like when dealing with the project of removal of level crossings in regard to time and cost?”. When it comes to repealing an overpass easement in order to be able to close a level crossing, a railway plan can be established to facilitate such easement measures. Although it does not directly imply "construction of the railway", if it is to be cancelled without support in a railway plan, the conditions of protection in Chapter 5 and Chapter 7 of the FBL must be fully applied. The method used was partly interview and partly study of railway plans and cadastral dossier. Twelve interviews were conducted, of which seven represented the Swedish Transport Agency and five persons who represented the National Land Survey, who were considered to fulfil the response required to answer the questions to an enough extent. There were only a limited number of railway plans which included only the closure of level crossings. However, there were a number of railway plans that dealt with the closure of level crossings, but then in connection with other measures which by law are the construction or rebuilding of railways. The united nations global sustainable objective strive to reach 17 objectives before the year 2030 wereof objective 11 is as follows: “Sustainable cities and societies”, which was considered to be connected with this essays problem formulation. It has emerged from the result that there are both pros and cons of applying railway plan in connection with the closure of level crossings. What can be stated after the implementation of the study is that the Swedish Transport Administration has a desire to implement more railway plans at complicated level crossings and the National Land Survey Office sees certain advantages from a handling perspective to applying a railway plan. / Trafikverket strävar efter att effektivisera, öka kapaciteten och säkra tillgängligheten för landets vägar och järnvägar genom att bland annat ta bort järnvägsövergångar. Ökad kapacitet i form av högre hastigheter ställer högre krav på säkerheten vid järnvägsövergångar och stängning av plankorsningar mellan enskilda vägar och statliga järnvägar är en angelägen åtgärd nationellt. Målet med examensarbetet var att efterforska arbetsmetodiken kring stängning av plankorsningar samt att utreda vilka faktorer som påverkar effektiviteten och framdriften i projekt vid dels planläggningen dels genomförande av åtgärden. De frågeställningar som behandlades i denna uppsats var: ”Hur ser den nuvarande hanteringen ut vid stängning av plankorsningar och i vilka situationer skulle det vara användbart att tillämpa järnvägsplan?” och ”Hur ser projektgenomförandet ut i projekt som berör borttagande av plankorsningar med avseende på tid och kostnader?”. När det gäller upphävande av överfartsservitut i syfte att kunna stänga en plankorsning kan en järnvägsplan upprättas för att underlätta sådana servitutsåtgärder även om det inte direkt innebär "byggande av järnväg". Om det däremot ska upphävas utan stöd i järnvägsplan ska skyddsvillkoren i 5 kap och 7 kap FBL tillämpas fullt ut. Metoderna som användes var intervjuer och studie av järnvägsplaner och förrättningsakter. Det genomfördes tolv intervjuer, där sju personer representerade Trafikverket och fem förrättningslantmätare representerade Lantmäterimyndigheten, vilket bedömdes uppfylla den svarsmättnad som krävdes för att få frågeställningen besvarad med tillräcklig räckvidd. Det fanns ett begränsat antal järnvägsplaner som endast behandlade stängning av en plankorsning. Det fanns däremot ett flertal järnvägsplaner som behandlade stängning av plankorsningar, men då i samband med andra åtgärder som enligt lag är byggande eller ombyggnad av järnväg. Förenta nationernas globala hållbara mål består av 17 mål som syftar till att utrota fattigdom, stoppa klimatförändringar och skapa fredliga och trygga samhällen innan 2030. Varav mål 11 lyder: ”Hållbara städer och samhällen”, vilket ansågs berör denna uppsats problemformulering. Resultaten visade både för- och nackdelar med att tillämpa järnvägsplan vid stängning av plankorsningar. Det som kan konstateras efter den genomföra studien är att Trafikverket har en vilja att genomföra fler järnvägsplaner vid komplicerade plankorsningar och Lantmäterimyndigheten ser vissa fördelar från ett handläggningsperspektiv att tillämpa järnvägsplan.

Neste trabalho teve-se por objetivo estimar parâmetros genéticos e avaliar o potencial agronômico em gerações F2 e F3:2 de cruzamentos do tipo adaptado x exótico em soja, quanto ao potencial de gerar descendentes agronomicamente superiores e com resistência à ferrugem asiática. Ademais, procurou-se estudar a resistência a doenças de final de ciclo (DFC). Os experimentos nas gerações F2 e F3:2 foram conduzidos em 2007 e 2007/08, respectivamente, em áreas experimentais do Departamento de Genética, ESALQ/USP, Piracicaba, SP, Brasil. Foram utilizados como genitores exóticos resistentes: 1) PI 200487 (Kinoshita), 2) PI 471904 (Orba), 3) PI 459025 (Bing nan) e 4) PI 200526 (Shira Nuhi); e, como genitores adaptados, mas suscetíveis à ferrugem, foram utilizados os genótipos: 1) IAC-100, 2) MGBR 46 (Conquista), 3) BRSMT (Pintado), 4) BRS-154 e 5) BRS-232. Foram avaliados 27 cruzamentos em F2, sendo dez com recíprocos e sete sem recíprocos, e mais os nove genitores. Na geração F3:2 foram avaliados dois cruzamentos: Conquista x Orba e IAC-100 x Kinoshita; cada cruzamento foi avaliado em dois experimentos principais. Um destes experimentos foi protegido com aplicações dos fungicidas Impact Duo & Opera para controle da ferrugem e das DFC, enquanto que o outro recebeu apenas o fungicida Derosal para controle das DFC. Foram avaliadas 40 progênies F3:2 por recíproco de cada cruzamento. Além dos experimentos principais, foram instalados três experimentos auxiliares com 12 genótipos: quatro genitores exóticos, cinco genitores adaptados e três genótipos adicionais (BR-16, IAS-5 e OC-4). Cada experimento auxiliar recebeu um tratamento diferenciado de fungicida: Impact Duo & Opera, Derosal e Controle (sem aplicação de fungicida); o contraste do Impact Duo & Opera vs Derosal forneceu uma estimativa do efeito da ferrugem, enquanto que o contraste entre Derosal e Controle estimou o efeito das DFC. Os resultados levaram às seguintes conclusões: a) a estratégia de se usar diferentes tipos de fungicidas mostrou-se eficiente para estimar a reação das plantas à ferrugem e a DFC, em termos de produtividade de grãos; b) em relação às notas de severidade da ferrugem, a discriminação genotípica foi melhor observada a partir de 97 dias (S2) e 104 dias (S3) após a semeadura, respectivamente para genitores nos experimentos auxiliares e cruzamentos; c) no cultivo de outono (geração F2 e genitores), o hábito de crescimento indeterminado foi um caráter importante para o desempenho favorável dos genótipos; d) foram identificadas fontes de resistência/tolerância à ferrugem e a DFC entre os genitores exóticos e também, adaptados e adicionais; e) em F2, os cruzamentos envolvendo o genitor Orba foram os mais promissores e os cruzamentos com o genitor Shira Nuhi foram os menos promissores; o caráter valor agronômico mostrou-se eficiente na seleção de cruzamentos, pelos altos coeficientes de herdabilidade, observados no sentido amplo; f) em F3:2, o cruzamento IAC-100 x Kinoshita mostrou-se mais promissor do que o cruzamento Conquista x Orba, para o desenvolvimento de linhagens com níveis apropriados de resistência à ferrugem e produtividade de grãos; g) nas duas gerações as diferenças entre recíprocos ocorreram apenas em situações pontuais. / This work aimed to estimate genetic parameters and evaluate the agronomic potential in F2 and F3:2 generations of adapted x exotic soybean crosses, concerning the potential to generate progenies with higher agronomic offspring and with resistance to Asian soybean rust. Moreover, the resistance to late season leaf diseases (LSLD) was studied. The experiments in F2 and F3:2 generations were carried out during 2007 and 2007/08, respectively, in the Department of Genetics, ESALQ/USP, Piracicaba, SP, Brazil. As resistant exotic parents were used: 1) PI 200487 (Kinoshita), 2) PI 471904 (Orba), 3) PI 459025 (Bing nan) and 4) PI 200526 (Shira Nuhi); and as adapted parents, but susceptible to soybean rust, were used: 1) IAC-100, 2) MGBR 46 (Conquista), 3) BRSMT (Pintado), 4) BRS-154 and 5) BRS-232. Twenty seven crosses in generation F2, ten with reciprocals and seven without reciprocals were evaluated, plus the nine parents. In F3:2 generation, two crosses were evaluated: Conquista x Orba and IAC-100 x Kinoshita. Each cross was evaluated in two main experiments, one of them was protected with applications of the Impact Duo & Opera fungicides, to control soybean rust and LSLD, while the other experiment was spraied with Derosal to control only the LSLD. For each reciprocal cross, were evaluated 40 progenies in F3:2. Besides the main experiments, three auxiliary experiments were installed, with twelve genotypes: four exotic parents, five adapted parents and three additional parents (BR-16, IAS-5 and OC-4). Each experiment received one differential treatment of fungicide: Impact Duo & Opera, Derosal and Control (no applications of fungicide); the contrast Impact Duo & Operal vs. Derosal gave an estimate of the Asian soybean rust effect, while the contrast between Derosal and Control estimated the LSLD effect. The results led to the following results: a) the strategy of using different types of fungicides were effective in estimating the response of plants to rust and LSLD, in terms of grain yield; b) in relation to the notes of severity of rust, genetic discrimination was better observed from 97 days (S2) and 104 days (S3) after sowing, respectively for parents in the auxiliary experiments and crosses; c) in the cultivation of autumn (parents and F2 generation), the indeterminate growth habit was an important character to the favorable performance of the genotypes; d) sources of resistance/tolerance to rust and LSLD were identified among exotic, adapted and additional parents; e) In F2 generation, crosses having Orba as parent were the most promising and crosses involving Shira Nuhi were the less promising; agronomic value (VA) showed to be efficient for cross selection, by the high magnitude of the heritability coefficient, observed in broad sense; f) In F3:2 generation, the cross IAC-100 x Kinoshita showed more promising than Conquista x Orba cross, for the development of lines with appropriate levels of resistance to soybean rust and high grain yield; g) in the two generations, the differences between reciprocals occurred only in specific situations.

Detecção de outliers é uma tarefa fundamental para descoberta de conhecimento em mineração de dados. Cujo objetivo é identificar as amostras de dados que desviam acentuadamente dos padrões apresentados num conjunto de dados. Neste trabalho, apresentamos uma nova técnica de detecção de outliers baseada em caminhada determinística do turista. Especificamente um caminhante é iniciado para cada exemplar de dado, variando-se o tamanho da memória, assim, um exemplar recebe uma alta pontuação de outlier ao participar em poucos atratores, enquanto que receberá uma baixa pontuação no caso de participar numa grande quantidade de atratores. Os resultados experimentais em cenários artificiais e reais evidenciaram um bom desempenho do método proposto. Em comparação com os métodos clássicos, o método proposto apresenta as seguintes características salientes: 1) Identifica os outliers através da determinação de estruturas no espaço de dados ao invés de considerar apenas características físicas, como distância, similaridade e densidade. 2) É capaz de detectar outliers internos, situados em regiões entre dois ou mais agrupamentos. 3) Com a variação do valor de memória, os caminhantes conseguem extrair tanto características locais, quanto globais do conjunto de dados. 4) O método proposto é determinístico, não exigindo diversas execuções (em contraste às técnicas estocásticas). Além disso, neste trabalho caracterizamos, pela primeira vez, que as dinâmicas exibidas pela caminhada do turista podem gerar atratores complexos, com diversos cruzamentos. Sendo que estes podem revelar estruturas ainda mais detalhadas e consequentemente melhorar a detecção dos outliers. / Outlier detection is a fundamental task for knowledge discovery in data mining. It aims to detect data items that deviate from the general pattern of a given data set. In this work, we present a new outlier detection technique using tourist walks. Specifically, starting from each data sample and varying the memory size, a data sample gets a higher outlier score if it participates in few tourist walk attractors, while it gets a low score if it participates in a large number of attractors. Experimental results on artificial and real data sets show good performance of the proposed method. In comparison to classical methods, the proposed one shows the following salient features: 1) It finds out outliers by identifying the structure of the input data set instead of considering only physical features, such as distance, similarity or density. 2) It can detect not only external outliers as classical methods do, but also internal outliers staying among various normal data groups. 3) By varying the memory size, the tourist walks can characterize both local and global structures of the data set. 4) The proposed method is a deterministic technique. Therefore, only one run is sufficient, in contrast to stochastic techniques, which require many runs. Moreover, in this work, we find, for the first time, that tourist walks can generate complex attractors in various crossing shapes. Such complex attractors reveal data structures in more details. Consequently, it can improve the outlier detection.

Neste trabalho estudamos o processo de foto-ionização associativa(PAI) em uma amostra fria de átomos de sódio com o objetivo entender os efeitos dos estados repulsivos e dimensão da colisão. Realizamos experimentos de PAI com duas cores em uma armadilha magneto-óptica adicionando um feixe de prova com intensidade, frequências e polarização ajustáveis. O formato dos átomos aprisionados também foi uma das variáveis no estudo da PAI. Para os átomos em formação esférica, observamos uma mudança marcante no comportamento da constante de taxa de formação da foto-ionização associativa(K) para um determinado domínio de frequências, e essa mudança no comportamento pode ser atribuída a participação de estados moleculares repulsivos na PAI e a formação de um possível cruzamento evitado entre os níveis moleculares. No atomotron ,armadilha atômica em forma de anel, variamos a polarização do laser de prova e constatamos que a razão entre K das polarizações paralela e perpendicular ao movimento dos átomos é igual a 4. Uma comparação entre K do atomotron e o da armadilha esférica em função da intensidade do feixe de prova, nos mostrou uma diferença no comportamento e no valor da constante de taxa. / Photoassociative ionization (PAI) in a cold sample of sodium atoms was the main subject of our studies as a way to understand the effects of repulsive states and collision dimensions. Two-color PAI experiment were preformed in a magneto-optical trap (MOT) trough the addition of a probe laser beam, the intensity, polarization and frequency of that probe laser were tunable. The shape of the trapped atoms also could be changed. In a spherical shape MOT, we observed a marked change in the PAI rate constant (K) for a definite frequency range, and that change can be attributed to the influence of repulsive molecular states and the a possible formation of an avoided crossing between molecular levels. In atomotron, ring shaped mot, we changed the polarization of the probe beam, and saw that the ratio between K for a polarization parallel to the atoms motion and a perpendicular one is 4. Comparing the K as a function of the intensity between a spherical shaped mot and atomotron showed us a difference in the behavior and the value of the rate constant.

Ácaros fitoseídeos são eficientes predadores de ácaros pragas em algumas culturas. A precisa identificação das espécies é o passo inicial na seleção de inimigos naturais em um projeto de controle biológico. Os ácaros são geralmente identificados com base nas características morfológicas, mas aspectos biológicos e ecológicos, e mais recentemente características moleculares vêm sendo usadas nesse processo. Populações dos fitoseídeos identificados como Euseius citrifolius Denmark & Muma provenientes de Arroio do Meio-RS, Campinas-SP e Petrolina-PE, e Euseius concordis (Chant) procedentes de Arroio do Meio, Jaguariúna-SP, Petrolina, Pontes e Lacerda-MT e Viçosa-MG foram estudados em relação a morfologia, compatibilidade reprodutiva e características moleculares. A caracterização morfológica correspondeu as medições de estruturas de fêmeas e machos. A compatibilidade reprodutiva foi avaliada através de cruzamentos e retrocruzamentos homogâmicos e heterogâmicos. A caracterização molecular foi realizada com o seqüenciamento dos espaços internos transcritos (ITS1 e ITS2) do DNA ribossomal. Relações significativas foram observadas dentro de cada população entre o comprimento médio das setas e as respectivas amplitudes de variação. Ambos os sexos de E. citrifolius de Petrolina e E.concordis de Jaguariúna tiveram algumas setas mais curtas que as demais populações da mesma espécie; esta última diferiu marcadamente da população de Petrolina. A comparação das medições das estruturas de cada população e dos espécimes tipo de E. citrifolius e E. concordis confirmaram a identificação morfológica preliminar das populações ao nível de espécie. Medições de machos resultantes de cruzamentos heterogâmicos indicaram que essas espécies se reproduzem por pseudo-arrenotoquia. Incompatibilidade parcial foi observada nos cruzamentos heterogâmicos envolvendo fêmeas de E. citrifolius de Petrolina; descendentes produziram poucos ovos e inviáveis quando retrocruzadas com machos das populações parentais. Machos de Petrolina produziram descendentes viáveis quando cruzados com fêmeas de Arroio do Meio e Campinas. Não ocorreu oviposição nos cruzamentos e retrocruzamentos heterogâmicos envolvendo fêmeas de E. concordis de Petrolina. Nos cruzamentos heterogâmicos envolvendo machos de Petrolina a oviposição foi reduzida e somente machos (viáveis) foram produzidos. Cruzamentos de fêmeas de Pontes e Lacerda e machos de Jaguariúna e vice-versa produziram somente machos. Entretanto o fluxo gênico entre essas populações seria possível indiretamente, através de cruzamentos entre essas populações e a população de Arroio do Meio. Populações de Arroio do Meio, Jaguariúna, Pontes e Lacerda e Viçosa pertencem a mesma espécie. Maior variação entre as populações foi observada no espaçador ITS1. O seqüenciamento dos espaçadores ITS1 e ITS2 permitiu discriminar entre os grupos de populações identificadas como E. citrifolius de E. concordis. O seqüenciamento dos ITSs pode ser aplicado como uma ferramenta complementar na identificação de fitoseídeos. Apesar do fato de que alguns tipos de diferenças foram sempre observadas nesta tese entre a população de Petrolina identificada preliminarmente como E. concordis, não é conveniente descrever esta população como uma nova espécie, devido a dificuldade em separar indivíduos dessa população daqueles das populações identificadas como E.concordis. Para uma conclusão, é sugerido que outros estudos de cruzamentos sejam conduzidos com populações morfologicamente identificadas como E. concordis coletadas entre Petrolina e Viçosa, e que a caracterização molecular envolvendo o gene citocromo oxidase seja conduzida. / Phytoseiidae mites are efficient predators of pest mites on several crops. Precise identification is the initial step in the selection of natural enemies in a biological control project. Mites are usually identified by their morphology, but biological and ecological aspects and, more recently, molecular characteristics have also been used in this process. Populations of phytoseiid mites identified as Euseius citrifolius Denmark & Muma from Arroio do Meio-RS, Campinas-SP and Petrolina-PE, and E. concordis (Chant) from Arroio do Meio, Jaguariúna-SP, Petrolina Pontes e Lacerda-MT and Viçosa-MG were studied in relation to morphology, reproductive compatibility and molecular characteristics. Morphological characterization corresponded to measurements of structures of females and males. Reproductive compatibility was evaluated by homogamic and heterogamic crosses and backcrosses. Molecular characterization was done by sequencing the internal transcribed spacers of the ribosomal DNA (ITS1 and ITS2). Significant relationships were observed within each population between mean setal lengths and the respective ranges. Both sexes of E. citrifolius from Petrolina and E. concordis from Jaguariúna had some setae shorter than other populations of the same species; the latter differed most markedly from the Petrolina population. A comparison of the measurements of structures for each population and type specimens of E. citrifolius and E. concordis confirmed the preliminary morphological identification of the populations at species level. Measurements of males resulting from heterogamic crosses indicated that both species reproduce by pseudo-arrhenotoky. Partial incompatibility was observed in heterogamic crosses involving females of E. citrifolius from Petrolina; progeny produced just few, unviable eggs when backcrossed with males of the parental populations. Males from Petrolina produced viable offspring when crossed with females from Arroio do Meio or Campinas. No eggs were produced in heterogamic crosses and backcrosses involving females of E. concordis from Petrolina. In heterogamic crosses involving males from Petrolina, oviposition was reduced and only (viable) males were produced. Crosses of females from Pontes e Lacerda and males from Jaguariúna and vice-versa produced only male progeny. However, gene flow between those population could be possible indirectly, through crosses between those populations and Arroio do Meio population. Populations from Arroio do Meio, Jaguariúna, Pontes e Lacerda and Viçosa belong to a same species. Most of the molecular variation between populations was observed in ITS1. The sequencing of ITS1 and ITS2 allowed the discrimination between the group of populations identified as E. citrifolius from that identified as E. concordis. With the information presently available, sequencing of ITSs can be applied as a complementary tool to identify phytoseiids. Despite the fact that some type of differences were always observed in this thesis between the Petrolina population preliminarily identified as E. concordis and the remaining populations, it is not convenient to describe such population as a new species presently, given the difficulty in separating individuals from that population from those of populations identified as E. concordis. For a conclusion, it is suggested that other crossing studies be conducted with populations morphologically identifiable as E. concordis collected between Petrolina and Viçosa, and that the characterization of the cytochrome oxidase gene be conducted.

O conhecimento sobre o sistema de cruzamento e a forma como a diversidade genética está distribuída em populações de espécies arbóreas é de fundamental importância para se planejar seu manejo e conservação. Espécies arbóreas pioneiras estão cada vez mais freqüentes dentro e fora dos fragmentos florestais remanescentes. Trema micrantha é uma das primeiras espécies a se estabelecer em áreas abandonadas e Cecropia pachystachya é uma espécie pioneira dióica e seletivamente higrófita. Ambas são polinizadas pelo vento e produzem muitas sementes que são dispersas por animais. Estudou-se a diversidade e estrutura genética e o sistema de cruzamento em populações de ambas espécies e, para T. micrantha, avaliou-se também o banco de sementes como um potencial tampão gênico para a espécie. As populações foram amostradas na Estação Ecológica dos Caetetus (Gália-S.P.) e na Reserva Florestal de Santa Genebra (Campinas-S.P.), onde se amostrou 177 indivíduos de T. micrantha, distribuídos em 6 e 5 subpopulações, e 178 indivíduos de C. pachystachya, em 2 e 3 subpopulações, nos respectivos fragmentos. Os sistemas de cruzamento foram avaliados com base em 24 progênies de 10 indivíduos por progênie de cada espécie. As estimativas para os parâmetros de diversidade genética nas populações de plantas do dossel foram obtidas a partir do polimorfismo de oito locos isoenzimáticos, num total de 20 alelos para T. micrantha e sete locos isoenzimáticos num total de 17 alelos para C. pachystachya. Da mesma forma, utilizou-se 13 locos com 30 alelos para T. micrantha e sete locos com 17 alelos para C. pachystachya, no estudo dos sistemas de cruzamento. Verificou-se que as populações de ambas espécies contêm baixos níveis de endogamia ( f ) de -0,204 e 0,066 em T. micrantha; -0,052 e 0,049 em C. pachystachya, em ambos fragmentos) e alta diversidade ( e H ) de 0,373 e 0,392 em T. micrantha; 0,355 e 0,335 em C. pachystachya, em ambos fragmentos). A divergência genética existente entre populações é menor do que entre subpopulações ( de 0,026 e -0,007, de 0,086 e 0,068, para C. pachystachya e T. micrantha, respectivamente). T. micrantha apresenta sistema de cruzamento misto, com preferência por alogamia ( de 0,966 e 0,819, em ambos fragmentos) e está sujeita a variações na freqüência de cruzamentos endogâmicos ( p &#952;ˆ SP &#952;ˆ m tˆ Fˆ de -0,022 e 0,103) e a altas taxas de cruzamentos biparentais ( de 0,653 e 0,605). Sendo espécie dióica, as estimativas de fecundação cruzada obtidas para C. pachystachya não corresponderam às expectativas ( de 0,816 e 0,794). No entanto, as estimativas indicaram que espécie está sujeita a cruzamentos biparentais ( de 0,868 e 0,990). Os resultados sugerem que uma acirrada competição nas etapas de germinação e desenvolvimento de plântulas durante a regeneração de T. micrantha, bem como a distribuição espacial em clareiras e o eficiente fluxo gênico nesta espécie são fundamentais para manter altas taxas de diversidade genética em suas populações. / The knowledge about the breeding system and the genetic structure of populations of tree species is of great importance in order to plan their management and conservation. Pioneer tree species are more and more frequent inside and outside remaining forest fragments. Trema micrantha is one of the first tree species to be established in abandoned areas and Cecropia pachystachya is a pioneer dioecious tree and selectively adapted to wet soils. Both species are pollinated by wind and produce seeds that are dispersed by various animals species. We studied the diversity, the genetic structure and the mating system of both pioneer species populations. The seed bank of T. micrantha was also evaluated as a potential genetic buffer for this species. Populations were collected in the "Estação Ecológica dos Caetetus" (Gália, São Paulo State, Brazil) and in the "Reserva Florestal de Santa Genebra" (Campinas, São Paulo State, Brazil), where 177 plants of T. micrantha, distributed into six and five subpopulations, and 178 plants of C. pachystachya, distributed into two and three subpopulations were respectively sampled from both fragments. Ten seeds per plant and 24 plants per population were germinated to generate progeny arrays used in the mating system analyses. The estimates for the genetic diversity genetic parameters in the plant populations of the dossel were obtained from eight polymorphic isozyme loci with 20 alleles for T. micrantha and seven isoenzymatic loci with 17 alleles for C. pachystachya. Similarly, 13 loci with 30 alleles for T. micrantha and seven loci with 17 alleles for C. pachystachya were used in the mating system study. The results showed that populations of both species have low levels of inbreeding ( = -0.204 and 0.066 for T. micrantha; = -0.052 and 0.049 for C. pachystachya, in both fragments, respectively) and high diversity ( fˆ fˆ e Hˆ = 0.373 and 0.392 for T. micrantha; e Hˆ = 0.355 and 0.335 for C. pachystachya, in both fragments). The genetic divergence among populations was lower than among subpopulations ( = 0.026 and -0.007; = 0.086 and 0.068, for C. pachystachya and T. micrantha, respectively). T. micrantha presents a mixed mating system, with preference to outcrossing ( = 0.966 and 0.819, in both fragments) and is subject to variations in the inbreeding frequency and high rates of biparental mating ( = 0.653 and 0.605 in both fragments, respectively). The estimates obtain for C. pachystachya did not correspond to the expectations of a dioecious species ( = 0.816 and 0.794 in both fragments). A significant proportion of related individuals were observed ( p &#952;ˆ SP &#952;ˆ m tˆ p rˆ m tˆ s t m t ˆ ˆ &#8722; = 0.072 and 0.128, both fragments), indicating a spacial structure of individuals under the species natural condition. The estimates showed that the great majority of C. pachystachya progenies are composed of full-sib matings ( = 0.868 and 0.990 in both fragments), resulting from biparental matings. Besides, the results suggest that a tough competition in the phases of germination and seedling development during the regeneration of T. micrantha, as well as the spatial distribution in gaps and the efficient gene flow are important in order to maintain high rates of genetic diversity in its populations.