[pt] A presente investigação objetivou analisar a consolidação e configurações do Trap no Brasil, no sentido das reexistências da arte periférica na contemporaneidade. Para tal, a dissertação buscou, a princípio, abordar em que consiste arte periférica, tomando como ponto de partida o gênero em análise. Frente a isso, abordou a arte periférica não enquanto uma limitação do espaço em que ela pode ocupar e/ou alcançar, mas sim da produção de atores sociais que experienciam as realidades de uma sociedade capitalista e excludente. Logo após, tratou o Trap, desde o Hip Hop e o Rap, sob a perspectiva memorialística, como fator de identidade, em que as produções vão das palavras, das escritas ficcionais à performance. O estudo bibliográfico inicial culminou em uma pesquisa de campo, de cunho qualitativo, com a realização de entrevistas, por meio de questionário aberto, com produtores e trappers. Através de uma análise discursiva, compreendeu-se a hibridez do Trap com outros gêneros, como Hip Hop, Rap e Funk, porém apresentando uma outra enunciação do povo preto, em outros espaços, denunciando os racismos, por meio de cenários e objetos elitizados. Sendo assim, por mais que se hibridizem em alguns aspectos, em outros se distanciam, não só pelas narrativas das canções, mas também com o Trap possuindo uma batida mais forte, com sons mais rápidos, com o uso de sintetizadores multidimensionais, a partir de diversos sons eletrônicos, que trazem a sensação do som ecoar por todos os lados. Percebeuse, portanto, que o Trap vem para demonstrar os novos cenários e esferas sociais que a periferia alcança na contemporaneidade. / [en] The present investigation aimed to analyze the consolidation and configurations of Trap in Brazil, in order in the sense of re-existence of peripheral art in contemporary times. To this end, the dissertation sought, at first, to address what peripheral art consists of, taking the genre under analysis as a starting point. Faced with this, peripheral art was approached not as a limitation of the space it can occupy and/or reach, but rather as the production of social actors who experience the realities of a capitalist and excluding society. Soon after, he treated Trap, from Hip Hop and Rap, from a memorialistic perspective, as an identity factor, in which productions range from words, from fictional writings to performance. The initial bibliographical study culminated in a field research, of a qualitative nature, with interviews, through an open questionnaire, with producers and trappers. Through a discursive analysis, the hybridity of Trap with other genres, such as Hip Hop, Rap and Funk, was understood, but presenting another enunciation of black people, in other spaces, denouncing racism, through elitist scenarios and objects. Therefore, although they are hybridized in some respects, in others they distance themselves, not only due to the narratives of the songs, but also with Trap having a stronger beat, with faster sounds, with the use of multidimensional synthesizers, from several electronic sounds, which bring the feeling of sound echoing everywhere. It was noticed, therefore, that Trap comes to demonstrate the new scenarios and social spheres that the periphery reaches in contemporary times.

Trapped ions in a Paul trap can experience micromotion on top of the wanted secular motion.Micromotion can for example cause Doppler shifts in spectroscopy measurements, making it important to know the amplitude of the motion. In this master thesis we use the correlation between RF driving the trap and photons emitted by a single Beryllium ion during the fluorescence detection to determine the micromotion. This method also allows us to investigate the effect on micromotion from a phase mismatch between RF electrodes. The photon correlation method is compared to measuring the micromotion by taking the ratio between the micromotion sideband and the carrier transition, and also to a simulation of the residual RF fields in the trap by a finite element method. Finally, we vary the path length of RF lines, to tune the phase on individual RF electrodes. The result is that the phase mismatch effect is more than an order of magnitude less than expected from theory. / Fångade joner i en Paul-fälla upplever mikrorörelse utöver den önskade sekulära rörelsen. Mikrorörelse kan till exempel orsaka Dopplerförskjutning i spektroskopimätningar, vilket gör det viktigt att veta amplituden av rörelsen. I det här examensarbetet använder vi korrelationen mellan RF som driver jonfällan och fotoner utsända från en enskild berylliumjon under fluorescens-detektion, för att mäta mikrorörelsen. Den här metoden tillåter oss också att undersöka effekten på mikrorörelse från en fasförskjutning mellan RF-elektroder. Fotonkorrelationsmetoden jämförs med en mätning av mikrorörelse genom att ta förhållandet mellan mikrorörelse-sidobandet och bärar-övergången, och också med en simulering av RF-fälten i jonfällan med en finit element-metod. Slutligen varierar vi längden på RF-kopplingen, för att justera fasen mellan individuella RF-elektroder. Resultatet är att effekten från fasförskjutningen är mer än en storleksordning mindre än vad teorin förutsagt.

I conducted surveys of amphibian, reptile, and small mammal communities surrounding 4 isolated, upland and 6 stream-connected temporary wetlands on Tombigbee National Forest and Noxubee National Wildlife Refuge in north Mississippi from May 2001 - March 2006. Trap captures yielded 17 amphibian species (n = 11,142), 21 reptile species (n = 541), and 10 small mammal species (n = 472). Upland pools supported greater diversity of Ambystomatid salamanders, anurans, lizards, and mice (Peromyscus spp.), than floodplain pools. Factors including landscape position of pools, proximity to alternate water sources, and barriers to dispersal potentially influenced faunal communities of temporary wetlands. Infrared-triggered cameras were used to monitor mammalian activity surrounding ephemeral wetlands to determine potential depredation of pitfall traps. Raccoons (Procyon lotor) accounted for most images (35% total images). I assessed relative effectiveness of sampling techniques to capture and retain herpetiles in presence of depredation. I tested pitfall trap, funnel trap, and pitfall trap combined with exclusion cover along driftence arrays. Overall, pitfall traps of both designs produced more captures than funnels, and excluded-pitfalls yielded greater captures than un-excluded pitfalls for most amphibians. Overall mortality rates were <2% of total captures with anurans accounting for most (63.30%) mortality. I submit that in long-term studies, pitfall traps with exclusion are prudent to limit sampling bias and mortality occurring with depredation of captured herpetofauna. During trapping, pit-traps of both designs yielded incidental captures of small mammals. Capture rates for small mammals were similar in un-excluded pitfall traps and excluded pitfall traps. Southern short-tailed shrews (Blarina carolinensis) and mice accounted for 93% of total captures and suffered 76% and 52% mortality, respectively, potentially due to exposure, starvation, flooding, and/or depredation. Additionally, one species listed as rare in Mississippi was captured during herpetofaunal surveys, oldfield mouse (Peromyscus polionotus). Due to potential impact of pitfall trapping on small mammals, I recommend that researchers either alter trapping methods to address non-target hazards (frequency of checking traps, providing shelter) or work cooperatively using an integrated survey approach for herpetiles and small mammals to limit trap mortality.

The thesis aims at building an experimental setup for conducting the boundary ejection and resonance ejection experiments on wide variety of ion trap mass analyzers. The experimental setup has two parts namely power electronics circuits and mechanical assembly. The focus of the thesis is on the electronics hardware which provides various power sources required for the operation of ion trap mass spectrometer. The electronics circuits discussed in the thesis have better performance, flexibility and ruggedness compared to the existing setup. The traditional power supplies used in ion trap mass spectrometers are all linear supplies. But one major drawback of these supplies is the high power dissipation and consequently, the power efficiency degrades. We are trying to introduce switch mode power supplies to reduce the power dissipation loss and eventually increase the power efficiency. In the course of the work the following power supplies have been developed. The supplies are - 1.Constant current source, 2.Filament base, 3.gating power supply and pulsing circuit, 4.High voltage DC power supply and 5. High voltage RF generator.

This thesis presents axially symmetric equivalents of three-dimensional rf ion traps. Miniaturization in mass spectrometry has focused on miniaturizing mass analyzers. Decrease in mass analyzer size facilitates reduction of the size of other components of a mass spectrometer, especially the radio frequency electronics and vacuum system. Miniaturized mass analyzers are made using advanced microfabrication techniques. Due to micromachining limitations, it is not possible to fabricate ion traps with exact axial symmetry. The motivation for this thesis is to investigate newer three-dimensional geometries which do not possess axial symmetry, but are equivalent in performance to axially symmetric ion traps. We introduce a 3D geometry called square ion trap(SIT) having a ring electrode made off our square shaped planar surfaces and square shaped endcap electrodes resembling a cuboid. Initially, a SIT geometry is taken and it will be investigated if this unknown 3D geometry can be made equivalent to a well characterized, axially symmetric ion trap like the CIT. The purpose of showing equivalence will be to understand the ion dynamics and fields inside the new 3D SIT. This thesis consists of five chapters. In Chapter 1, we present the necessary background information required to understand the operation of a mass spectrometer. The Paul trap geometry is introduced followed by the derivation of equation of ion motion inside the Paul trap. The Mathieu stability plot and the modes of operation of a mass spectrometer are briefly discussed. The chapter ends by outlining scope of the thesis. Chapter 2 describes the computational methods employed by us in the thesis. First, the geometry of square ion trap is introduced. Then the boundary element method(BEM) which is used to compute the charge distribution on the electrode surfaces is discussed. This is followed by the three-dimensional Green’s function which should be employed for non-axially symmetric structures. The method to calculate potential and field inside the ion trap from charge distribution is shown. Calculation of multipole coefficients for non-axially symmetric traps using charge distribution is shown. The methods used to generate ion trajectory and stability plot are discussed. The Nelder-Mead simplex method used for optimization is also presented. To verify our numerical methods of charge calculation, we have taken standard textbook problems and compared our results with those presented therein. The multipoles calculation, field and ion trajectory was verified by comparing the results for the Paul trap and cylindrical ion traps. Chapter 3 presents the results for axially symmetric equivalents of 3D rf ion traps. SIT geometry of dimensions equivalent to the CIT0 are taken and field and multipoles are studied in it. Then optimization is applied to create a CIT geometry equivalent to the SIT under study. Axial field and ion trajectory was compared and observed to be matching. Finally, stability plot was generated for both SIT and its equivalent CIT and was found to present a close match. Chapter 4 presents the numerical results obtained for three-dimensional rf ion trap equivalent of CIT. In this chapter, we have considered two standard geometries, the CIT0 and the CITopt. Optimization was applied to create SIT geometries equivalent to the CIT0 and the CITopt respectively. Comparison of fields and ion trajectory confirmed the fact that non-axially symmetric traps can be created equivalent to any axially symmetric ion trap. We have also considered another case of axially symmetric circular planar ion trap which has an annular ring electrode and two planar endcap electrodes. Square equivalent of circular planar trap was created by the optimizer and its equivalent was verified by ion trajectory comparison. Chapter 5 summarizes the thesis with a few concluding remarks.

In this thesis we have focussed on two types of axially symmetric ion trap mass analysers viz., the quadrupole ion trap mass analyser and the toroidal ion trap mass analyser. We have undertaken three numerical studies in this thesis, one study is on the quadrupole ion trap mass analysers and two studies are on the toroidal ion trap mass analysers. The first study is related to improvement of the sensitivity of quadrupole ion trap mass analysers operated in the resonance ejection mode. In the second study we have discussed methods to determine the multipole coefficients in the toroidal ion trap mass analysers. The third study investigates the stability of ions in the toroidal ion trap mass analysers. The first study presents a technique to cause unidirectional ion ejection in a quadrupole ion trap mass spectrometer operated in the resonance ejection mode. In this technique a modified auxiliary dipolar excitation signal is applied to the endcap electrodes. This modified signal is a linear combination of two signals. The first signal is the nominal dipolar excitation signal which is applied across the endcap electrodes and the second signal is the second harmonic of the first signal, the amplitude of the second harmonic being larger than that of the fundamental. We have investigated the effect of the following parameters on achieving unidirectional ion ejection: primary signal amplitude, ratio of amplitude of second harmonic to that of primary signal amplitude, different operating points, different scan rates, different mass to charge ratios and different damping constants. In all these simulations unidirectional ejection of destabilized ions has been successfully achieved. The second study presents methods to determine multipole coefficients for describing the potential in toroidal ion trap mass analysers. Three different methods have been presented to compute the toroidal multipole coefficients. The first method uses a least square fit and is useful when we have ability to compute potential at a set of points in the trapping region. In the second method we use the Discrete Fourier Transform of potentials on a circle in the trapping region. The third method uses surface charge distribution obtained from the Boundary Element Method to compute these coefficients. Using these multipole coefficients we have presented (1) equations of ion motion in toroidal ion traps (2) the Mathieu parameters in terms of multipole coefficients and (3) the secular frequency of ion motion in these traps. It has been shown that the secular frequency obtained from our method has a good match with that obtained from numerical trajectory simulation. The third study presents stability of ions in practical toroidal ion trap mass analysers. Here we have taken up for investigation four geometries with apertures and truncation of electrodes. The stability is obtained in UDC-VRF plane and later this is converted into A-Q plane on the Mathieu stability plot. Though the plots in terms of Mathieu parameters for these structures are qualitatively similar to the corresponding plot of linear ion trap mass analysers, there is a significant difference. The stability plots of these have regions of nonlinear resonances where ion motion is unstable. These resonances have been briefly investigated and it is proposed that they occur on account of hexapole and octopole contributions to the field in these toroidal ion traps.

This thesis is a numerical study of fields within ion traps having segmented electrodes1. The focus is on two cylindrical ion trap structures, two Orbit rap structures and one planar structure which mimics the field of the Orbit rap. In all these geometries, the segments which comprise the electrodes are easily Machin able rings and plates. By applying suitable potential to the different segments, the fields within these geometries are made to mimic the fields in the respective ideal structures. This thesis is divided into 6 chapters. Chapter 1 presents introduction and background information relevant to this work. A brief description of the Quadrupole Ion Trap (QIT) and the Orbit rap is given. The role of numerical simulations in the design of an ion trap geometry is briefly outlined. The motivation of this thesis is presented. The chapter ends by describing the scope of the thesis. Chapter 2 presents a general description of computational methods used throughout this work. The Boundary Element Methods (BEM) is first described. Both 2D and 3D BEM are used in this work. The software for 3D BEM is newly developed and hence 3D BEM is described in more detail. A verification of 3D BEM is presented with a few examples. The Runge-Kutta method used to compute the trajectory of ion is presented. A brief overview of the Nelder-Mead method of function minimization is given. The computational techniques specifically used to obtain the results in Chapter 3, 4 and 5 are presented in the respective chapters. Chapter 3 presents segmented electrode geometries of the Cylindrical Ion Trap (CIT). In these geometries, the electrodes of the CIT are split into number of mini-electrodes and different voltages are applied to these segmented electrodes to achieve the desired field. Two geometries of the segmented electrode CIT will be investigated. In the first, we retain the flat end cap electrodes of the CIT but split the ring electrode into five mini-rings. In the second configuration, we split the ring electrode of the CIT into three mini-rings and 1The term ‘segmented electrode’ used in this thesis has the same connotation as the term ‘split-electrode’ used in Sonalikar and Mohanty (2013). also divide the end caps into two mini-discs. By applying different potentials to the mini-rings and mini-discs of these geometries we will show that the field within the trap can be optimized to desired values. Two different types of fields will be targeted. In the first, potentials are adjusted to obtain a linear electric field and, in the second, a controlled higher order even multipole field are obtained by adjusting the potential. It will be shown that the different potentials to the segmented electrodes can be derived from a single RF generator by connecting appropriate capacitor terminations to segmented electrodes. The field within the trap can be modified by changing the value of the external capacitors. Chapter 4 presents segmented electrode geometries which are possible alternatives for the Orbitrap. Two segmented-electrode structures, ORB1 and ORB2, to mimic the electric field of the Orbitrap, will be investigated. In the ORB1, the inner spindle-like electrode and the outer barrel-like electrode of the Orbitrap are replaced by rings and discs of fixed radii, respectively. In this structure two segmented end cap electrodes are added. In this geometry, different potentials are applied to the different electrodes keeping top-bottom symmetry intact. In the second geometry, ORB2, the inner and outer electrodes of the Orbitrap are replaced by an approximate step structure which follows the profile of the Orbitrap electrodes. For the purpose of comparing the performance of ORB1 and ORB2 with that of the Orbitrap, the following studies will be undertaken: (1) variation of electric potential, (2) computation of ion trajectories, (3) measurement of image currents. These studies will be carried out using both 2D and 3D Boundary Element Method (BEM), the 3D BEM is developed specifically for this study. It will be seen in these investigations that ORB1 and ORB2 have performance similar to that of the Orbitrap, with the performance of the ORB1 being seen to be marginally superior to that of the ORB2. It will be shown that with proper optimization, geometries containing far fewer electrodes can be used as mass analysers. A novel technique of optimization of the electric field is proposed with the objective of minimizing the dependence of axial frequency of ion motion on the initial position of an ion. The results on the optimization of 9 and 15 segmented-electrode trap having the same design as ORB1 show that it can provide accurate mass analysis. Chapter 5 presents a segmented electrode planar geometry named as PORB used to mimic the electric field of the Orbit rap. This geometry has two planes, each plane consisting of 30 concentric ring electrodes. Although the geometry of PORB does not have conventional inner and outer electrodes of the Orbit rap, it will be shown that by selecting appropriate geometry parameters and suitable potentials for the ring electrodes, this geometry can trap the ions into an orbital motion similar to that in the Orbit rap. The performance of the planar geometry is studied by comparing the variation of potential, ion trajectories and image current in this geometry with that in the Orbit rap. The optimization of applied potentials is performed to correct the errors in the electric field so that the variation of axial frequency of ions with their initial position is minimized. Chapter 6 presents the summary and a few concluding remarks

In der vorliegenden Arbeit wird die erstmalige Erzeugung eines<br />Bose-Einstein-Kondensates in einer Mikrochip-Falle beschrieben; dies ist eine Magnetfalle für Neutralatome, die mithilfe stromführender Leiterbahnen auf einem Chipsubstrat gebildet wird. Die Eigenschaften dieser Chipfallen, speziell die hohen<br />Magnetfeldgradienten und -krümmungen, haben es ermöglicht, die<br />Bose-Einstein-Kondensation in weniger als einer Sekunde Verdampfungskühlzeit zu erreichen, was rund eine Größenordnung schneller als in bisher verwendeten Magnetfallen ist<br />und ein Faktor drei schneller als auf dem bisher schnellsten Weg in einer optischen Dipolfalle. Damit verbunden sind die Ansprüche<br />an den experimentellen Aufbau, insbesondere das Vakuumsystem und<br />den Laseraufbau, deutlich gesunken.<br /><br />Weiterhin wird der zerstörungsfreie Transport des Bose-Einstein-Kondensats entlang der Chipoberfläche über makroskopische Distanzen demonstriert wie auch erstmalig die Aufspaltung eines Kondensates in zwei getrennte Kondensate mit rein magnetischen Mitteln.<br /><br />Diese Resultate, nämlich kohärente Materie in einem integrierten<br />atomoptischen System manipulieren zu können, lassen hoffen, daß in<br />naher Zukunft Anwendungen wie Atominterferometrie, Untersuchungen<br />zu niederdimensionalen Quantengasen und<br />Quanteninformationsverarbeitung 'on-chip' verwirklicht werden<br />können.

La régulation de l’expression génétique est essentielle afin qu’un organisme puisse s’adapter aux changements environnementaux. Chez les bactéries, la régulation peut s’effectuer à plusieurs étapes de l’expression des gènes (transcription, stabilité de l’ARN, traduction, maturation et dégradation des protéines) et par des mécanismes impliquant différents types de molécules (ADN, ARN, protéines, métabolites ou ions inorganiques). Traditionnellement, les protéines se situaient au centre de ces mécanismes de régulation. On sait maintenant que certains ARN, dont les riborégulateurs, ont également un grand rôle à jouer dans ce processus. Un riborégulateur est un élément génétique retrouvé dans une région non-codante de certains ARN messagers (ARNm), qui peut lier directement un ligand spécifique afin de réguler l’expression de son transcrit. Chez Escherichia coli (E. coli), trois riborégulateurs lient la thiamine pyrophosphate (TPP). Un d’entre eux, le riborégulateur thiB, n’a toujours pas été étudié. On croit qu’il contrôlerait, au niveau de l’initiation de la traduction, l’expression de l’opéron thiBPQ encodant un transporteur ABC de la thiamine. De plus, un petit ARN nommé SroA a précédemment été identifié grâce à des techniques de séquençage d’ARN. SroA correspond à l’aptamère du riborégulateur thiB, mais aucun rôle ne lui a été attribué à ce jour. Le présent mémoire porte sur la caractérisation du riborégulateur thiB d’E. coli. Dans un premier temps, nous avons démontré que le riborégulateur est fonctionnel. Le mécanisme permettant la régulation génétique en cis est cependant plus complexe que seulement la régulation prédite au niveau traductionnel. Dans un second temps, nous avons utilisé deux approches différentes à l’échelle transcriptomique afin de vérifier si SroA régule l’expression de certains ARNm en trans. Plusieurs cibles potentielles découlent de cette étude. Une caractérisation préliminaire de certaines d’entre elles est présentée ici et devra être poursuivie par des travaux subséquents. Les résultats présentés ici suggèrent que le riborégulateur thiB régulerait l’expression de l’opéron thiBPQ (en cis) et d’autres gènes en trans.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.