The complementary metal-oxide-semiconductor (CMOS) scaling process of the recent decades, coupled with new device structures and materials, has aggravated thermal problems and turned them into major reliability issues for deeply-scaled devices. As a consequence, the thermal transport dynamic and its impact on the device performance at submicron dimensions is established as a contemporary theme. In this context, a new selfconsistent electro-thermal particle-based device simulator for the study of self-heating effects in p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) based in silicon is developed and presented. The electrical module of the tool utilizes the Ensemble Monte Carlo method to perform the charge transport, whereas the thermal module evaluates the non-isothermal temperature profiles by solving the phonon energy balance equations for both acoustic and optical phonon baths. These temperature profiles are fed back into the electrical module, which adjusts the carriers’ scattering rate accordingly, thus, properly accounting for the device current capability degradation. The developed tool proved to be suitable for sub-100 nm device simulations, and it was used to perform relevant case study simulations of 24-nm channel length bulk and fully-depleted siliconon- insulator (FD-SOI) MOSFETs. General device parameters extracted from the simulations are qualitatively in agreement with the expected behavior, as well as data from the literature, ensuring the proper operation of the tool. Electro-thermal simulations of bulk and FD-SOI devices provided both acoustic and optical phonon temperature profiles across the transistor structure, as well as the heat generation map and the device power dissipation. Some results were also extracted via Joule heating thermal model, and they are presented for comparison. The current degradation due to self-heating was found to be significant for FD-SOI devices, but very modest for bulk ones. At a fixed bias point of VD =VG = 1:5 V, for instance, bulk devices presented a current variation of as much as 0:75%, whereas for FD-SOI devices it reached up to 8:82% for Tgate = 400 K. Hot spot acoustic (lattice) and optical phonon temperatures were extracted as a function of the applied bias for both topologies. The lattice temperature rise, for instance, exceeded 10 K and 150 K over the heat sink temperature for bulk and FD-SOI transistors, respectively, observing the same bias point and gate temperature presented earlier. The particle-based nature of the tool is also suitable for the study of the impact of trap activity in MOSFETs and its interplay with self-heating effects. Simulations of charge traps were used to analyze the statistical distribution of the current deviations in 25-nm bulk MOSFETs due to traps. The simulations showed that these deviations are exponentially-distributed, as experimentally observed and reported in the literature. Electro-thermal simulations of charge traps in bulk and FD-SOI transistors revealed that the largest degradation on the device current occurs when the effects of self-heating and trap activity take place simultaneously. At lower biases, the impact of charge traps dominates the current degradation, whereas the self-heating component prevails for larger biases.

Nesta tese são apresentados estudos do impacto de armadilhas no desempenho elétrico de MOSFETs em nível de circuito e um simulador Ensamble Monte Carlo (EMC) é apresentado visando a análise do impacto de armadilhas em nível de dispositivo. O impacto de eventos de captura e emissão de portadores por armadilhas na performance e confiabilidade de circuitos é estudada. Para tanto, um simulador baseado em SPICE que leva em consideração a atividade de armadilhas em simulações transientes foi desenvolvido e é apresentado seguido de estudos de caso em células SRAM, circuitos combinacionais, ferramentas de SSTA e em osciladores em anel. Foi também desenvolvida uma ferramenta de simulação de dispositivo (TCAD) atomística baseada no método EMC para MOSFETs do tipo p. Este simulador é apresentado em detalhes e seu funcionamento é testado conceitualmente e através de comparações com ferramentas comerciais similares. / This thesis presents studies on the impact of charge traps in MOSFETs at the circuit level, and a Ensemble Monte Carlo (EMC) simulation tool is developed to perform analysis on trap impact on PMOSFETs. The impact of charge trapping on the performance and reliability of circuits is studied. A SPICE based simulator, which takes into account the trap activity in transient simulations, was developed and used on case studies of SRAM, combinational circuits, SSTA tools and ring oscillators. An atomistic device simulator (TCAD) for modeling of p-type MOSFETs based on the EMC simulation method was also developed. The simulator is explained in details and its well function is tested.

A taxa de infecção mínima (TIM) em flebotomíneos é uma informação útil para estudos epidemiológicos em leishmaniose. Quando estes estudos de campo contem grande número de insetos, a PCR é a indicada para caracterização por Leishmania nos vetores. Este estudo avaliou a PCR na identificação da (TIM) natural por Leishmania spp. em Lutzomyia longipalpis e, ao mesmo tempo, determinou as (TIM) por Leishmania spp em uma micro-região endêmica do Estado de São Paulo. Na primeira parte deste estudo, as avaliações do desempenho das PCRs convencional (cPCR) e em tempo real (qPCR) foram realizadas em 66 amostras de conteúdo intestinal de flebotomíneos utilizados no xenodiagnóstico (30 positivas e 36 negativas). O material contido nas lâminas foi transferido para tubos com solução salina estéril e congeladas a -20° C por cerca de 12 meses. Os marcadores moleculares utilizados foram RV1/RV2 para L. (L.) infantum na cPCR; e Linj31 para sub gênero (L.) (Leishmania) na qPCR. Das 30 amostras positivas, 20 (67%) e 21 (70%) foram positivas utilizando os marcadores RV1/RV2 e Linj31, respectivamente. Das 36 amostras negativas no xenodiagnóstico, 2 (5%) foram positivas em todos os marcadores moleculares. Na segunda parte foram analisados insetos capturados durante 2 a 3 noites/mês durante 11 meses (janeiro a novembro de 2012) usando 10 armadilhas automáticas de luz do tipo CDC ao redor de um canil em uma transição entre bairro periurbano e urbano de Dracena. As áreas de captura foram agrupadas em 3 zonas para determinar a TIM. Um total de 1.690 Lu. longipalpis foram capturadas durante o período estudado. Destes, 292 (17,25%) eram fêmeas de flebotomíneos e foram agrupadas em 165 pools (1 a 5 insetos) para extração de DNA e análise por PCR. Resultados positivos para L. (L.) infantum na cPCR e qPCR foram vistos em 7,28% (12/165) e 4,85% (8/165) das amostras, respectivamente. Estes dados confirmam que espécimes capturados na área de estudo estavam infectados por L. (L.) infantum. A TIM durante os 11 meses de capturas foi de 4,10% (292 fêmeas coletadas). Os ecótopos com TIM mais altos foram canil, galinheiro e casa 2. Flebotomíneos infectados estavam presentes nos locais de captura com abundância de hospedeiros. O maior número de pools positivos (6/93) foi obtido no galinheiro, todavia a maior TIM foi obtido em um domícilio (1/6) 16,67%. / The minimum infection rate (MIR) in sandflies is a useful information for epidemiological studies on leishmaniasis. When these field studies consider large numbers of insects, PCR is indicated for identification and characterization of Leishmania in the vectors. This study evaluated a PCR in the identification of natural (MIR) by Leishmania spp. in Lutzomyia longipalpis and, at the same time, determined MIR by Leishmania spp in a micro region endemic in São Paulo State . In the first part of this study, the performance evaluation of conventional PCR (cPCR) and real-time PCR (qPCR) were carried out on 66 intestinal contents samples of non-xenodiagnostic sandflies (30 positive and 36 negative). The material contained in the slides was transferred to tubes with sterile saline solution and frozen at -20 ° C for about 12 months. The molecular markers used were RV1 / RV2 for L. (L.) infantum in cPCR; E Linj31 for sub genus (L.) Leishmania on qPCR. From the 30 positive samples, 20 (67%) and 21 (70%) were positive using the RV1 / RV2 and Linj31 markers, respectively. From the 36 negative xenodiagnostic samples, 2 (5%) were positive in all molecular markers. In the second part, we analyzed insects captured during 2 to 3 nights / month for 11 months (January to November 2012) using 10 CDC automatic light traps around a kennel in a transition between urban and suburb of Dracena. Capture areas were grouped into 3 zones to determine MIR. A total of 1,690 Lu. longipalpis were captured during the study period. From these, 292 (17.25%) were female sand flies and were grouped into 165 pools (1 to 5 insects) for DNA extraction and PCR analysis. Positive results for L. (L.) infantum in cPCR and qPCR were seen in 7.28% (12/165) and 4.85% (8/165) of the samples, respectively. These data confirm that the specimens captured in the study area were infected by L. (L.) infantum. The MIR during the 11 months of captures was 4.10% (292 females collected). The highest MIR ecotopes were kennel, chicken coop and house 2. Infected sandflies were presented at capture sites with host abundance. The highest number of positive pools (6/93) was obtained in henhouse, however the highest MIR was obtained in a domicile (1/6) 16.67%.

Neste trabalho apresentamos a construção de uma armadilha de dipolo com laser de CO2 que envolveu a utilização de novas e modernas tecnologias nunca utilizadas pelo nosso grupo até então. Podemos destacar a construção de uma nova câmara de aprisionamento com grande acesso óptico, getters como fonte de átomos e um laser de CO2 de alta potência e sua óptica. Demonstramos o aprisionamento de átomos de 85Rb em uma armadilha magnética e magneto-óptica e analisamos sua dinâmica, obtendo resultados das taxas de perdas provocadas por colisões entre átomos aprisionados e átomos quentes provenientes do vapor de fundo e do getter. Este entendimento será importante na implementação da técnica totalmente óptica de aprisionamento simultâneo de átomos de Rb e moléculas de Rb2. / In this work we present the construction of an optical dipole trap using a CO2 laser, which involves the use of news and modern technologies never utilized by our group up to now. We have builded a new trap chamber with large optical access, used atomic dispensers as an atomic source and a high power CO2 laser and its optical components. We have demonstrated trapping and cooling of 85 Rb in a magneto-optical trap as well as and magnetic trap. By analyze its dynamic, we have obtained results on the collisional loss rates between trapped atoms imprisoned and hot atoms originating from the background gas. This understanding will be important in the implementation of the technical one entirely optical trap for Rb atoms as well as Rb2 molecules.

Non-native species are increasing globally, and with this increase, it is likely that there will be new, unique relationships found among non-natives as well as additional impacts on native species. Rats and mongooses have been introduced to islands throughout the world where they impact native species, including birds, reptiles, and amphibians. The coqui frog was introduced to Hawaii in the 1980’s, where there were already abundant rat and mongoose populations. Previous research suggests that the high densities of coqui frogs may provide enough of a new food source for mongooses and rats that their populations would grow larger than they would without coqui frogs, and that this would exacerbate the negative effects that these predators have on native birds. We investigated whether there are relationships between coqui presence, and the local abundance of introduced rats and mongoose on the island of Hawaii. We also investigated at these 12 sites whether there were indirect effects of coquis on bird nest predation rates using camera traps on artificial nests. Finally, we interpret our results in light of an analysis of the stomach contents of mongooses and rats, and data collected from remote cameras monitoring scavengers of dead coqui frogs. We compared abundances of mammals in coqui invaded plots and uninvaded plots. In areas where coquis were present, we found a greater number of mongooses, and less Pacific rats. Both predators consume coquis, but mongooses were more important consumers of live and dead coquis. Shifts in mongoose and rat diets were observed in coqui invaded and uninvaded plots. It may be that coqui frogs are competing with rats because we found more fruit in rat stomachs collected in coqui invaded compared to uninvaded plots. We did not observe any difference in nest predation rates with and without coquis. Our results show that the coqui may serve as novel prey and/or competitors to non-native mammals.

Dans les technologies CMOS avancées, les défauts microscopiques localisées à l'interface Si (Nit) ou dans l'oxyde de grille (Nox) dégradent les performances des transistors CMOS, en augmentant le bruit de basse fréquence (LFN). Ces défauts sont généralement induits par le processus de fabrication ou par le vieillissement de l'appareil sous tension électrique (BTI, porteurs chauds). Dans des transistors canal SiGe ou III-V, leur densité est beaucoup plus élevé que dans le silicium et leur nature microscopique est encore inconnue. En outre, en sub 10 nm 3D comme nanofils, ces défauts répartis spatialement induisent des effets stochastiques typiques responsables de la "variabilité temporelle" de la performance de l'appareil. Cette nouvelle composante dynamique de la variabilité doit maintenant être envisagée en plus de la variabilité statique bien connu pour obtenir circuits fonctionnels et fiables. Aujourd'hui donc, il devient essentiel de bien comprendre les mécanismes de piégeage induites par ces défauts afin de concevoir et fabriquer des technologies CMOS robustes et fiables pour les nœuds de sub 10 nm. / In advanced CMOS technologies, microscopic defects localized at the Si interface (Nit) or within the gate oxide (Nox) degrade the performance of CMOS transistors, by increasing the low frequency noise (LFN). These defects are generally induced by the fabrication process or by the ageing of the device under electrical stress (BTI, Hot Carriers). In SiGe or III-V channel transistors, their density is much higher than in silicon and their microscopic nature still is unknown. In addition, in sub 10nm 3D like nanowires, these spatially distributed defects induce typical stochastic effects responsible for “temporal variability” of the device performance. This new dynamic variability component must now be considered in addition of the well-known static variability to obtain functional and reliable circuits. Therefore today it becomes essential to well understand the trapping mechanisms induced by these defects in order to design & fabricate robust and reliable CMOS technologies for sub 10nm nodes.

All of New Zealand's five endemic species of mudfish (Neochanna) are threatened, and translocation has been recommended as an option for conservation. This research undertakes a translocation of black mudfish (Neochanna diversus) into wetland margins of Lake Kaituna, in the Waikato region, and addresses research questions applicable to improving translocation success. Results from this research are intended to aid possible future translocations of the more threatened Northland mudfish (Neochanna heleios) and other genetically distinct populations of black mudfish. Captive rearing of juveniles collected from the wild is currently the most feasible option for sourcing translocation stock. Mudfish juveniles (greater than 25 mm T.L.) had greater survival rates, compared to mudfish fry less than 25 mm T.L. Mudfish growth was far greater when fed on a combined diet of brine shrimp (Artemia salina) and white worms (Enchytraeus albidus) than when fed exclusively on brine shrimp. Temperature was found to have a small effect on mudfish growth, with a slightly greater growth in fish at 15 C than those at 10 C. The introduced species Gambusia affinis has been the subject of concern for mudfish conservation and commonly found at wetland sites suitable for mudfish translocation. Found to prey on mudfish fry and eggs in aquaria, it was important to determine the effects of Gambusia density prior to undertaking a translocation to a location where Gambusia were present. Investigations were made into the effect of Gambusia density on black mudfish juveniles in 9 outdoor mesocosms. Increasing Gambusia density was found to have an inhibitory effect on black mudfish growth. This may be due to increased competition for food, a theory supported by analysis of zooplankton communities, where, in the presence of Gambusia, large zooplankton had been removed and smaller rotifers flourished. Monitoring programmes are required to assess any impacts or improvements of mudfish populations, including those created by translocation. A Gee minnow trapping programme in outdoor mesocosms was conducted to test the reliability of traps, finding that water depth, mudfish density, mudfish memory and trap shyness had no effect on the trapability of mudfish. Trap position was found to have the most significant effect, with a greater number of mudfish caught when traps were set overnight at the surface than when set on the bottom of mesocosms. Black mudfish adults and juveniles were translocated into 18 pools (~1 m diameter) on the wetland margins of Lake Kaituna in September 2006, followed by monthly monitoring. Water quality monitoring and an assessment of hydrology and vegetation was undertaken. Habitat characterisation was found to be a key factor, with correlations between water quality data and trapping results finding fewer fish remaining in pools with less suitable characteristics for mudfish (e.g. high turbidity and conductivity). Other species were found to have a large impact, with predation by shortfinned eels (Anguilla australis) thought to have eliminated mudfish from some pools. In addition fewer mudfish were caught in pools with Gambusia, possibly due to increased competition.

<p>Photochromism has been investigated extensively during recent years. The large interest for information storage in memory applications is associated with the bi-stable character of the photochromism phenomena. In molecular photochromics, two isomers with different absorption spectrum can be obtained according to the specific wavelength of the light exposure. This reversible transformation process can be considered as optical writing/erasing step of a memory.</p><p>Here we first report the absorption spectra of solid-state films based on the blends consisting of PC molecules, the spirooxazine 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3’-[3H]phenanthr[9,10-b](1,4)oxazine] (PIII, Sigma-Aldrich, 32,256-3) and a polymer matrix host, poly(2-methoxy-5(2’-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). The bi-stability in conjugated polymer matrix is studied by following the time evolution of the optical properties of the blends.</p><p>Thereafter, the electrical performance of PC-polymer diodes is characterized and reported. While the PIII molecules in the blend bulks are switched to their low energy gap state, forming external energy levels above the valence band of MEH-PPV, the injected charges (hole-dominated) will be trapped by the low energy gap isomer of PIII and that leads to current modulation. PIII molecules can be switched between two energy gap states upon the photo-stimulation, and the I-V characteristics of the device can also be controlled reversibly via the photoisomerization. The retention time of the diode’s electrical switching fits quite well with the absorption characteristics of the blend films; this correspondence builds a good link between the film property and the device behavior.</p><p>Furthermore, we observed a two-trap system in the blend diodes from the I-V curves, and a model is proposed which can explain the schematic concept of the trap-limited current modulation. To combine the knowledge and information from the investigations above, we tested a novel device design based on a bi-layer of the PC and polymer materials, and the promising result for future work is presented in the end.</p>

In this thesis we present a computational study of “ion crystals”, the interesting patterns in which ions arrange themselves in ion traps such as Paul and Penning traps. In ion crystals the ions are in equilibrium due to the balance of the repulsive forces between the ions and the overall tendency of the ion trap to pull ions towards the trap centre. We have carried out a detailed investigation of ion crystals in Paul traps by solving their equations of motion numerically. We also propose a model called the spring–mass model to explain the formation of ion crystals. This model is far more efficient than direct numerical simulation for predicting ion crystal structures. Finally, we demonstrate that there is a power law relating distance of an ion from the trap centre in ion crystals to the applied RF voltage amplitude.

The number of motor proteins attached to cellular cargos is widely believed to influence intracellular transport processes and may play a role in transport regulation. However, to date, investigating the biophysics of multiple-motor dynamics has been challenging since the number of motors responsible for cargo motion is not easily characterized. This work examines the transport properties of structurally-defined motor complexes containing two kinesin-1 motors, from both an experimental and theoretical perspective. Motor complexes were synthesized using DNA as a molecular scaffold and engineered DNA-conjugated protein polymers as linkers to couple motors to scaffolds. After anchoring the motor complexes to a bead their dynamic properties were measured using an automated optical trapping instrument that could be used to perform both static (increasing load) and force-feedback (constant load) optical trapping experiments. Data from these experiments is compared to predictions from a microscopic transition rate model of multiple kinesin dynamics. Together, these studies uncovered that multiple kinesins typically cannot cooperate since the microtubule-bound configuration of a motor complex often prevents both kinesins from sharing cargo loads. Furthermore, multiple-motor behaviors are influenced by the fact that motor complexes display hysteretic force-velocity behaviors when applied loads change rapidly in time. Overall, such behaviors suggest the number of kinesins on a cargo will not be a key determinant of intracellular transport processes, and in turn, will not contribute appreciably to mechanisms that regulate cargo motion. However, this work also provides evidence that processive microtubule motors that are less efficient than kinesin (e.g., dynein) will cooperate productively, produce greater responses to motor number, and may therefore act as a regulator of cargo transport.