Elevada disponibilidade de bário (Ba) no meio de cultivo pode resultar em severa toxidez nas plantas. A toxidez causada pelo metal pesado nas plantas pode ser amenizada pelo fornecimento de nutrientes, particularmente o enxofre (S). Objetivou-se avaliar os parâmetros produtivos, sintomas visuais, estado nutricional, índice SPAD, indicadores de estresse (malondialdeído, peróxido de hidrogênio e prolina) e a atividade de enzimas do sistema antioxidante (glutationa redutase, superóxido dismutase, catalase, ascorbato peroxidase e guaiacol peroxidase) do capim tanzânia (Panicum maximum Jacq. cv. Tanzânia) cultivado com combinações de doses de S e de Ba na solução nutritiva, em casa de vegetação, em dois ciclos de crescimento das plantas. As plantas foram submetidas às combinações de cinco doses de S (0,1; 1,0; 1,9; 2,8 e 3,7 mmol L-1) com cinco doses de Ba (0,0; 2,5; 5,0; 10,0 e 20,0 mmol L-1), utilizando esquema fatorial fracionado (52), em blocos ao acaso, com seis repetições e seis plantas por unidade experimental. Os parâmetros produtivos e o estado nutricional das plantas foram severamente afetados pelas combinações de S e Ba em ambos os ciclos de crescimento. O aumento na dose de Ba na solução nutritiva prejudicou acentuadamente o crescimento e o estado nutricional das plantas, principalmente na área foliar, e nos nutrientes potássio e magnésio, enquanto o aumento da dose de S amenizou o efeito tóxico do metal. Maiores concentrações de malondialdeído foram observadas nas plantas que apresentaram maior acúmulo do metal pesado. As atividades das enzimas glutationa redutase, catalase e ascorbato peroxidase foram mais altas nas plantas cultivadas com baixo fornecimento de S, enquanto a atividade da guaiacol peroxidase foi aumentada com incremento das doses de Ba e de S. / High barium (Ba) availability in growth medium can cause severe toxicity in plants. Nutrient supply may mitigate heavy metal phytotoxicity, especially the sulphur (S) supply. The study was carried out to evaluate the plant growth, visual symptoms, nutritional status, indicators of stress (malondialdehyde, hydrogen peroxide and proline) and activities of the antioxidant enzymes (glutathione reductase, superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase) in Tanzania guineagrass (Panicum maximum Jacq. cv. Tanzania) grown with combinations of S rates and Ba rates in nutrient solution, in a greenhouse, for two growth periods. Plants received nutrient solutions where combinations of five S rates (0.1, 1.0, 1.9, 2.8 and 3.7 mmol L-1) with five Ba rates (0.0, 2.5, 5.0, 10.0 and 20.0 mmol L-1) were used in a fractionated factorial (52), in randomized block design, with six replications and six plants per experimental unit. Plant production and nutritional status were highly affected by combinations of S and Ba rates, in both growth periods. Increase on Ba rates impaired growth, mainly on leaf area production. Barium rates impaired nutritional status, mainly on potassium and calcium, while increasing on S rates alleviated Ba toxic effects. High concentrations of malondialdehyde was observed in plants with increase of Ba application. The activities of catalase and ascorbate peroxidase were high in plants grown with low S availability, while guaiacol peroxidase activity was enhanced by increasing Ba and S rates in the nutrient solution.

Elevada disponibilidade de bário (Ba) no meio de cultivo pode resultar em severa toxidez nas plantas. A toxidez causada pelo metal pesado nas plantas pode ser amenizada pelo fornecimento de nutrientes, particularmente o enxofre (S). Objetivou-se avaliar os parâmetros produtivos, sintomas visuais, estado nutricional, índice SPAD, indicadores de estresse (malondialdeído, peróxido de hidrogênio e prolina) e a atividade de enzimas do sistema antioxidante (glutationa redutase, superóxido dismutase, catalase, ascorbato peroxidase e guaiacol peroxidase) do capim tanzânia (Panicum maximum Jacq. cv. Tanzânia) cultivado com combinações de doses de S e de Ba na solução nutritiva, em casa de vegetação, em dois ciclos de crescimento das plantas. As plantas foram submetidas às combinações de cinco doses de S (0,1; 1,0; 1,9; 2,8 e 3,7 mmol L-1) com cinco doses de Ba (0,0; 2,5; 5,0; 10,0 e 20,0 mmol L-1), utilizando esquema fatorial fracionado (52), em blocos ao acaso, com seis repetições e seis plantas por unidade experimental. Os parâmetros produtivos e o estado nutricional das plantas foram severamente afetados pelas combinações de S e Ba em ambos os ciclos de crescimento. O aumento na dose de Ba na solução nutritiva prejudicou acentuadamente o crescimento e o estado nutricional das plantas, principalmente na área foliar, e nos nutrientes potássio e magnésio, enquanto o aumento da dose de S amenizou o efeito tóxico do metal. Maiores concentrações de malondialdeído foram observadas nas plantas que apresentaram maior acúmulo do metal pesado. As atividades das enzimas glutationa redutase, catalase e ascorbato peroxidase foram mais altas nas plantas cultivadas com baixo fornecimento de S, enquanto a atividade da guaiacol peroxidase foi aumentada com incremento das doses de Ba e de S. / High barium (Ba) availability in growth medium can cause severe toxicity in plants. Nutrient supply may mitigate heavy metal phytotoxicity, especially the sulphur (S) supply. The study was carried out to evaluate the plant growth, visual symptoms, nutritional status, indicators of stress (malondialdehyde, hydrogen peroxide and proline) and activities of the antioxidant enzymes (glutathione reductase, superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase) in Tanzania guineagrass (Panicum maximum Jacq. cv. Tanzania) grown with combinations of S rates and Ba rates in nutrient solution, in a greenhouse, for two growth periods. Plants received nutrient solutions where combinations of five S rates (0.1, 1.0, 1.9, 2.8 and 3.7 mmol L-1) with five Ba rates (0.0, 2.5, 5.0, 10.0 and 20.0 mmol L-1) were used in a fractionated factorial (52), in randomized block design, with six replications and six plants per experimental unit. Plant production and nutritional status were highly affected by combinations of S and Ba rates, in both growth periods. Increase on Ba rates impaired growth, mainly on leaf area production. Barium rates impaired nutritional status, mainly on potassium and calcium, while increasing on S rates alleviated Ba toxic effects. High concentrations of malondialdehyde was observed in plants with increase of Ba application. The activities of catalase and ascorbate peroxidase were high in plants grown with low S availability, while guaiacol peroxidase activity was enhanced by increasing Ba and S rates in the nutrient solution.

L’objectif de cette thèse est de développer un détecteur innovant de particules chargées, dénommé 3D Silicon Coincidence Avalanche Detector (3D-SiCAD), réalisable en technologie silicium CMOS standard avec des techniques d’intégration 3D. Son principe de fonctionnement est basé sur la détection en "coïncidence" entre deux diodes à avalanche en mode "Geiger" alignées verticalement, avec la finalité d’atteindre un niveau de bruit bien inférieur à celui de capteurs à avalanche standards, tout en gardant les avantages liés à l’utilisation de technologies CMOS; notamment la grande variété d’offres technologiques disponibles sur le marché, la possibilité d’intégrer dans un seul circuit un système complexe de détection, la facilité de migrer et mettre à jour le design vers une technologie CMOS plus moderne, et le faible de coût de fabrication. Le détecteur développé dans ce travail se révèle particulièrement adapté au domaine de la physique des particules de haute énergie ainsi qu’à la physique médicale - hadron thérapie, où des performances exigeantes sont demandées en termes de résistance aux rayonnements ionisants, "material budget", vitesse, bruit et résolution spatiale. Dans ce travail, un prototype a été conçu et fabriqué en technologie HV-CMOS 0,35µm, en utilisant un assemblage 3D de type "flip-chip" avec pour finalité de démontrer la faisabilité d’un tel détecteur. La caractérisation du prototype a finalement montré que le dispositif développé permet de détecter des particules chargées avec une excellente efficacité de détection, et que le mode "coïncidence" réduit considérablement le niveau de bruit. Ces résultats très prometteurs mettent en perspective la réalisation d’un système complet de détection CMOS basé sur ce nouveau concept. / The objective of this work is to develop a novel position sensitive charged particle detector referred to as "3D Silicon Coincidence Avalanche Detector" (3D-SiCAD). The working principle of this novel device relies on a "time-coincidence" mode detection between a pair of vertically aligned Geiger-mode avalanche diodes, with the aim of achieving negligible noise levels with respect to detectors based on conventional avalanche diodes, such as Silicon Photo-Multipliers (SiPM), and, at the same time, providing single charged particle detection capability thanks to the high charge multiplication gain, inherent of the Geiger-mode operation. A 3D-SiCAD could be particularly suitable for nuclear physics applications, in the field of High Energy Physics experiments and emerging Medical Physics applications such as hadron-therapy and Proton Computed Tomography whose future developments demand unprecedented figures in terms of material budget, noise, spatial resolution, radiation hardness, power consumption and cost-effectiveness. In this work, a 3D-SiCAD demonstrator has been successfully developed and fabricated in the Austria Micro-Systems High-Voltage 0.35 μm CMOS technology by adopting a “flip-chip” approach for the 3D-assembling. The characterization results allowed demonstrating the feasibility of this novel device and validating the expected performances in terms of excellent particle detection efficiency and noise rejection capability with respect to background counts.

Le Groupe de Recherche en Appareillage Médical de Sherbrooke (GRAMS) travaille actuellement sur un programme de recherche portant sur des photodiodes à avalanche monophotoniques (PAMP) opérées en mode Geiger en vue d'une application à la tomographie d’émission par positrons (TEP). Pour opérer dans ce mode, la PAMP, ou SPAD selon l’acronyme anglais (Single Photon Avalanche Diode), requiert un circuit d'étouffement (CE) pour, d’une part, arrêter l’avalanche pouvant causer sa destruction et, d’autre part, la réinitialiser en mode d’attente d’un nouveau photon. Le rôle de ce CE comprend également une électronique de communication vers les étages de traitement avancé de signaux. La performance temporelle optimale du CE est réalisée lorsqu’il est juxtaposé à la PAMP. Cependant, cela entraîne une réduction de la surface photosensible ; un élément crucial en imagerie. L’intégration 3D, à base d'interconnexions verticales, offr une solution élégante et performante à cette problématique par l’empilement de circuits intégrés possédant différentes fonctions (PAMP, CE et traitement avancé de signaux). Dans l’approche proposée, des circuits d’étouffement de 50 [mu]m x 50 [mu]m réalisés sur une technologie CMOS 130 nm 3D Tezzaron, contenant chacun 112 transistors, sont matricés afin de correspondre à une matrice de PAMP localisée sur une couche électronique supérieure. Chaque circuit d'étouffement possède une gigue temporelle de 7,47 ps RMS selon des simulations faites avec le logiciel Cadence. Le CE a la flexibilité d'ajuster les temps d'étouffement et de recharge pour la PAMP tout en présentant une faible consommation de puissance ( ~ 0,33 mW à 33 Mcps). La conception du PAMP nécessite de supporter des tensions supérieures aux 3,3 V de la technologie. Pour répondre à ce problème, des transistors à drain étendu (DEMOS) ont été réalisés. En raison de retards de production par les fabricants, les circuits n’ont pu être testés physiquement par des mesures. Les résultats de ce mémoire sont par conséquent basés sur des résultats de simulations avec le logiciel Cadence.

Abstract In this thesis, a new type of laser diode transmitter using enhanced gain-switching suitable for use with a single photon avalanche diode (SPAD) detector was developed and tested in the pulsed time-of-flight laser range finding (lidar) application. Several laser diode versions were tested and the driving electronics were developed. The driving electronics improvements enabled a pulsing frequency of up to 1 MHz, while the maximum laser output power was about 5–40 W depending on the laser diode dimensions. The large output power is advantageous especially in conditions of strong photon noise emerging from ambient light outdoors. The length of the laser pulse matches the jitter of a typical SPAD detector providing several advantages. The new laser pulser structure enables a compact rangefinder for 50 m distance measurement outdoors in sunny conditions with sub-centimeter precision (σ-value) at a valid distance measurement rate of more than 10 kHz, for example. Single photon range finding techniques were also shown to enable a char bed level measurement of a recovery boiler containing highly attenuating and dispersing flue gas. In addition, gated single photon detector techniques were shown to provide a rejection of fluorescent photons in a Raman spectroscope leading to a greatly improved signal-to-noise ratio. Photonic effects were also studied in the case of a pulsed time-of-flight laser rangefinder utilizing a linear photodetector. It was shown that signal photon noise has an effect on the optimum detector configuration, and that pulse detection jitter can be minimized with an appropriate timing discriminator. / Tiivistelmä Tässä työssä kehitettiin uudentyyppinen, tehostettua "gain-switchingiä" hyödyntävä laserdiodilähetin käytettäväksi yksittäisten fotonien avalanche-ilmaisimien (SPAD) kanssa, ja sitä testattiin pulssin lentoaikaan perustuvassa laseretäisyysmittaussovelluksessa. Useita laserdiodiversioita testattiin ja ohjauselektroniikkaa kehitettiin. Ohjauselektroniikan parannukset mahdollistivat jopa 1 MHz pulssitustaajuuden, kun taas laserin maksimiteho oli noin 5–40 W riippuen laserdiodin dimensioista. Suuri lähtöteho on edullinen varsinkin vahvoissa taustafotoniolosuhteissa ulkona. Laserpulssin pituus vastaa tyypillisen SPAD-ilmaisimen jitteriä tarjoten useita etuja. Uusi laserpulssitinrakenne mahdollistaa esimerkiksi kompaktin etäisyysmittarin 50 m mittausetäisyydelle ulkona aurinkoisessa olosuhteessa mm–cm -mittaustarkkuudella (σ-arvo) yli 10 kHz mittaustahdilla. Yksittäisten fotonien lentoaikamittaustekniikan osoitettiin myös mahdollistavan soodakattilan keon korkeuden mittauksen, jossa on voimakkaasti vaimentavaa ja dispersoivaa savukaasua. Lisäksi portitetun yksittäisten fotonien ilmaisutekniikan osoitettiin hylkäävän fluoresenssin synnyttämiä fotoneita Raman-spektroskoopissa, joka johtaa selvästi parempaan signaali-kohinasuhteeseen. Fotoni-ilmiöitä tutkittiin myös lineaarista valoilmaisinta hyödyntävän pulssin kulkuaikamittaukseen perustuvan lasertutkan tapauksessa. Osoitettiin, että signaalin fotonikohina vaikuttaa optimaaliseen ilmaisinkonfiguraatioon, ja että pulssin ilmaisujitteri voidaan minimoida sopivalla ajoitusdiskriminaattorilla.

Time-Resolved diffuse optics is a powerful and safe technique to quantify the optical properties (OP) for highly scattering media such as biological tissues. The OP values are correlated with the compositions of the measured objects, especially for the tissue chromophores such as hemoglobin. The OP are mainly the absorption and the reduced scattering coefficients that can be quantified for highly scattering media using Time-Resolved Diffuse Optical Spectroscopy (TR-DOS) systems. The OP can be retrieved using Time-Resolved Diffuse Optical Imaging (TR-DOI) systems to reconstruct the distribution of the OP in measured media. Therefore, TR-DOS and TR-DOI can be used for functional monitoring of brain and muscles, and to diagnose some diseases such as detection and localization for breast cancer and blood clot. In general, TR-DOI systems are non-invasive, reliable, and have a high temporal resolution. TR-DOI systems have been known for their complexity, bulkiness, and costly equipment such as light sources (picosecond pulsed laser) and detectors (single photon counters). Also, TR-DOI systems acquire a large amount of data and suffer from the computational cost of the image reconstruction process. These limitations hinder the usage of TR-DOI for widespread potential applications such as clinical measurements. The goals of this research project are to investigate approaches to eliminate two main limitations of TR-DOI systems. First, building TR-DOS systems using custom-designed free-running (FR) and time-gated (TG) SPAD detectors that are fabricated in low-cost standard CMOS technology instead of the costly photon counting and timing detectors. The FR-TR-DOS prototype has demonstrated comparable performance (for homogeneous objects measurements) with the reported TR-DOS prototypes that use commercial and expensive detectors. The TG-TR-DOS prototype has acquired raw data with a low level of noise and high dynamic range that enable this prototype to measure multilayered objects such as human heads. Second, building and evaluating TR-DOI prototype that uses a computationally efficient algorithm to reconstruct high quality 3D tomographic images by analyzing a small part of the acquired data. This work indicates the possibility to exploit the recent advances in the technologies of silicon detectors, and computation to build low-cost, compact, portable TR-DOI systems. These systems can expand the applications of TR-DOI and TR-DOS into several fields such as oncology, and neurology. / Thesis / Doctor of Philosophy (PhD)

The goal of this thesis is to analyze and compare the main characteristics of Prague Stock Exchange and Warsaw Stock Exchange. At first the attention is paid to the concept of "stock exchange" in the legal system of both countries. A short summary of the history of both exchanges is followed by a description of the organizational structure and comparison of the basic conditions of exchange membership. The individual market segments are analyzed as well as conditions for admission of financial instruments to those segments. The thesis also outlines the essential characteristics of trading systems in Prague and in Warsaw together with a list of basic types of trades. The final comparative analysis is devoted to the type and volume of financial instruments traded on both exchanges and settlement of those trades.

This master's thesis deals with the issue of volcanic ash as a complex and its impact on aviation, including the volcanic activity itself (conditions for its existence, for existence of eruptions and their basic products). In addition, the thesis also deals with effect of volcanic ash on aircraft and airports, possibilities of its detection or monitoring as well as mechanism of its spreading in airspace. The emphasis is laid mainly on air incidents related to volcanic ash and on danger it poses to the airspace of the Czech Republic.

A review of available corn relative maturity groups in Mississippi shows a limited range of maturity groups in use. Research focusing on expanding the range of maturity groups was conducted in MS in 2015 and 2016. Along with expanded maturity groups, treatments of fertilizer (10-34-0), foliar zinc, and a plant hormone blend were studied to shorten the growing season. Four site years in MS were studied to determine optimal plant maturity group and treatment for length of season. The results showed decreased yield of 0.09-0.15 Mg ha-1 (1.5-2.3 bu ac-1) for each day of decreasing relative maturity in three of four site years. The addition of starter fertilizer increased vegetative growth stage, plant height V5 and V7, SPAD values at V5, and significantly decreases days to tassel and silking reproductive growth stages but did not affect yield.