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As a defense against viral infection, plants are thought to use RNA-induced silencing complexes (RISCs) to target and cleave viral RNA. To counteract this, some viruses have evolved proteins to inhibit RISC-mediated activity, thus ensuring continued virulence. This research focused on the study and analysis of the anti-viral RNAi response to various viruses in plants to gain an understanding of how the plant defense operates on the molecular and biochemical levels. Nicotiana benthamiana plants were infected with Tomato bushy stunt virus (TBSV) and Tobacco rattle virus (TRV). These plants were subjected to column chromatography methods, and fractions contained a virus-specific ribonuclease activity, co-eluting with small interfering RNAs (siRNA), that was shown to be sensitive to inhibition with EDTA and enhanced by the addition of divalent metal cations. This ribonuclease activity co-purified with proteins that contained a domain from the hallmark RISC protein Argonaute family. To further study host responses to viral infection, monocots were infected with Panicum mosaic virus (PMV) and satellite panicum mosaic virus (SPMV) and also were subjected to column chromatography following infection. Preliminary studies show that fractions contained ribonuclease activity as well as siRNAs and proteins containing an Argonaute domain. Additionally, silencing suppressors have been directly implicated in interfering with RNAi pathways in plants. Studies involving Agrobacterium- and virus-vectored cDNA to express green fluorescent protein (GFP) were used to establish that cointroduced suppressors of RNAi can extend the production of a foreign protein for enhancement of biotechnological applications. It was found that the hordeivirus protein ?b contributes to enhancement of expression for the foreign protein GFP early in the infection, while the potyvirus protein HcPro and tombusvirus protein P19 enhance and extend protein production later in the infection.

(English) Oocyte-to-embryo transition (OET) is one of the most complex developmental events where a differentiated oocyte gives rise to a totipotent zygote. During the growth phase an oocyte prepares for fertilization and progression to zygotic genome activation. It does so by transcribing and storing the necessary mRNAs till a fully-grown oocyte attains transcriptional quiescence. Therefore, transcriptome regulation in a fully-grown oocyte is of utmost importance. Study of post-transcriptional regulatory pathways revealed that the small-RNA mediated regulatory pathways exist in a unique conformation in mouse oocytes. Endogenous RNAi pathway is essential for mouse female germline while miRNA pathway which is ubiquitously present in most cell types is dispensable for oocyte maturation and fertilization. My PhD project was aimed at understanding the constraints of the miRNA pathway in the oocyte which makes it non-functional. As a fully-grown oocyte is a huge cell with a proportionally large maternal transcriptome we analysed the miRNA: mRNA stoichiometry changes that occur from growing to the fully-grown mouse oocyte. Inability of miRNAs to accumulate during oocyte growth phase leads to their dilution in fully-grown oocyte rendering them inactive. Low miRNA concentrations were also observed in rat,...

Titre de l'écran-titre (visionné le 13 décembre 2023) / Ce mémoire présente le développement d'un système sur puce basé sur un processeur RISC-V dans le but de proposer une solution technologique pouvant être utilisée pour un instrument biomédical mesurant la concentration de neurotransmetteurs par l'utilisation d'une caméra. La solution présentée inclue les interfaces nécessaires au contrôle de cet instrument soit des sorties digitales pour le contrôle de pompes microfluidique et du capteur optique, une interface I2C et SPI pour interfacer la caméra, puis une interface UART pour envoyer le résultat à un système externe. Le système a été testé en simulation pour valider le fonctionnement de l'intégration puis a été implanté sur deux FPGAs, soit le Cyclone IV et le ZCU102. L'implémentation finale du prototype a été faite sur une technologie TSMC CMOS 180 nm. Le système peut fonctionner jusqu'à une fréquence de 37.5 MHz. Cependant, pour la fréquence de fonctionnement cible de 10 MHz, la consommation est de 162 mW. La performance du processeur RISC-V du système mesurée par CoreMark est de 0.58 CM/MHz. Le système d'exploitation Linux, ainsi que le code embarqué de gestion de la caméra, ont été testés sur la puce électronique fabriquée pour confirmer l'utilisabilité du système pour application prévue. Pour faciliter la programmation du système, un outil de programmation automatique a été développé. / This project presents the development of a system on a chip based on a RISC-V processor. In order to provide a technological solution that can be used for a biomedical instrument measuring the concentration of neurotransmitters with a spectrophotometer. The solution presented here includes the required interfaces for controlling this instruments such as digital outputs to control microfluidic pumps and optical sensor. Next the communication interfaces I2C and SPI are included to interface with the camera and a UART interface is used to transfer the results with an external system. The system has been simulated to validate functionality of the integration and was then implemented on two FPGAS (Cyclone IV and ZCU102). The final implementation of the prototype was achieved on a TSMC CMOS 180 nm technology. The system can be clocked up to 37.5 MHz while the target frequency of 10 MHz resulted in a power consumption of 162 mW. The performance of the RISC-V processor measured by the CoreMark benchmark was 0.58 CM/MHz. The Linux operating system, as well as the firmware for camera management, were tested on the IC in order to confirmthe usability of the system for its target use. To facilitate the programming process, an automated programming tool was developped.

RISC - Uma nova tendência em arquitetura de computadores. Este trabalho apresenta um estudo de como surgiu esta nova arquitetura, e suas características básicas, que a diferencia das arquiteturas convencionais. Uma proposta de microprocessador RISC é apresentada, com sua rota de dados completamente detalhada. Um simulador para arquitetura RISC foi então construído, para se testar este microprocessador. Para validar o simulador, que é a idéia principal deste trabalho, e para se avaliar a arquitetura do microprocessador proposto, usou-se o benchmark Dhrystone, e os resultados foram comparados com máquinas comerciais. / RISC - A new trend in computer architecture. This work presents a study of how this new architecture emerged, and the basic caracteristics that diferentiate it from the conventional architectures. A proposed RISC microprocessor is presented with the completely detailed data-path. A simulator for the RIse architecture was built to test this microprocessor. To validate the simulator, which is the main idea of this work, and to evaluate the architecture of the proposed microprocessor, the Dhrystone benchmark was used and the results were compared with commercial machines.

RISC - Uma nova tendência em arquitetura de computadores. Este trabalho apresenta um estudo de como surgiu esta nova arquitetura, e suas características básicas, que a diferencia das arquiteturas convencionais. Uma proposta de microprocessador RISC é apresentada, com sua rota de dados completamente detalhada. Um simulador para arquitetura RISC foi então construído, para se testar este microprocessador. Para validar o simulador, que é a idéia principal deste trabalho, e para se avaliar a arquitetura do microprocessador proposto, usou-se o benchmark Dhrystone, e os resultados foram comparados com máquinas comerciais. / RISC - A new trend in computer architecture. This work presents a study of how this new architecture emerged, and the basic caracteristics that diferentiate it from the conventional architectures. A proposed RISC microprocessor is presented with the completely detailed data-path. A simulator for the RIse architecture was built to test this microprocessor. To validate the simulator, which is the main idea of this work, and to evaluate the architecture of the proposed microprocessor, the Dhrystone benchmark was used and the results were compared with commercial machines.

The Elliptic Curve Digital Signature Algorithm (ECDSA) is the elliptic curve analog of the Digital Signature Algorithm (DSA) and a federal government approved digital signature method. In this thesis work, software optimization techniques were applied to speed up the ECDSA for a particular NTST curve over GF(p). The Montgomery multiplication is used extensively in the ECDSA. By taking advantage of the algorithmic properties of the Montgomery multiplication method, special structure of the curve parameters and also applying certain fundamental and specific software optimization techniques, we have achieved an overall 26% speed improvement. Further enhancements were made by implementing the Montgomery multiplication in the ARM assembly language that resulted in 44% speed improvement. The optimizations discussed in this thesis could easily be adapted to other curves with or without changes. / Graduation date: 2002

The Elliptic Curve Digital Signature Algorithm (ECDSA) is one of the most popular algorithms to digitally sign streams or blocks of data. In this thesis we concentrate on porting and optimizing the ECDSA on the ARM7 processor for a particular NIST curve over GF(2[superscript m]). The selected curve is a binary curve of order 233. We show that for this particular curve, the ECDSA can be implemented significantly faster than the general case. The optimized algorithms have been implemented in C and the ARM assembly. The analysis and performance results indicate that by using certain machine and curve specific techniques, the ECDSA signature can be made up to 41% faster. / Graduation date: 2002

La societat actual ens sotmet a situacions que es podrien considerar d'incertesa, així, aprenem a conviure amb un nou element, el risc, que condiciona i modifica la nostra percepció de la realitat. El plantejament fonamental d'aquest projecte parteix de la transcendència d'una adequada atenció a la dimensió comunicativa en determinats entorns de risc. 2. - Objecte d'estudi Aquest treball analitza la comunicació de risc en l'àmbit de la indústria química espanyola. Així, l'objecte d'estudi són les pràctiques comunicatives de l'àmbit públic i privat del les àrees geogràfiques analitzades (Andalusia, Astúries, Cantàbria, Catalunya i País Basc), i la seva valoració comparativa quant a la seva adaptació a les necessitats i expectatives de la població . 3. - Metodologia La metodologia utilitzada consta de diversos procediments específics: en primer lloc una anàlisi bibliogràfic, hemerogràfic i documental per elaborar la part teòrica i els fonaments generals del tema. En segon lloc una investigació empírica mitjançant un estudi de camp basat en tècniques d'anàlisi documental i entrevistes en profunditat amb els responsables de la gestió de la comunicació de les àrees estudiades tant a nivell d'empreses com d'administracions. (26 entrevistes). En tercer lloc l'observació participant desenvolupada al llarg de més de 20 anys de trajectòria professional vinculada a la comunicació de risc químic a l'àrea petroquímica de Tarragona. 4. - Resultats Genèricament es poden observar algunes conclusions: • Que en les àrees on no es porten a terme iniciatives de comunicació de risc, la percepció és desequilibrada, es produeix rebuig a l'activitat química en el seu conjunt i tots els sectors de la societat es veuen afectats. • Que les estratègies comunicatives públiques (de l'administració) responen cada vegada en major grau, al compliment de la legalitat vigent. • Que les iniciatives comunicatives del sector privat (associacions empresarials territorials / empreses) responen més aviat a estratègies de relacions públiques que a comunicació de risc, ja que fan especial incidència en temes de seguretat sense esmentar els riscos que la fan necessària. • Que destaquen algunes particularitats del polígon químic de Huelva respecte a la resta, especialment pel que fa a sensibilitat per les percepcions socials. • Que el polígon petroquímic de Tarragona lidera a nivell de l'Estat Espanyol les iniciatives en comunicació de risc, tant en l'àmbit públic com en el privat. / La sociedad actual nos somete a situaciones que se podrían considerar de incertidumbre, así, aprendemos a convivir con un nuevo elemento, el riesgo, que condiciona y modifica nuestra percepción de la realidad. El planteamiento fundamental de este proyecto parte de la trascendencia de una adecuada atención a la dimensión comunicativa en determinados entornos de riesgo. 2.- Objeto de estudio Este trabajo analiza la comunicación de riesgo en el ámbito de la industria química española. Así, el objeto de estudio son las practicas comunicativas del ámbito público y privado del las áreas geográficas analizadas (Andalucía, Asturias, Cantabria, Cataluña y País Vasco), y su valoración comparativa en cuanto a su adaptación a las necesidades y expectativas de la población. 3.- Metodología La metodología utilizada consta de diversos procedimientos específicos: en primer lugar un análisis bibliográfico, hemerográfico y documental para elaborar la parte teórica y los fundamentos generales del tema. En segundo lugar una investigación empírica mediante un estudio de campo basado en técnicas de análisis documental y entrevistas en profundidad con los responsables de la gestión de la comunicación de las áreas estudiadas tanto a nivel de empresas como de administraciones. (26 entrevistas). En tercer lugar la observación participante desarrollada a lo largo de mas de 20 años de trayectoria profesional vinculada a la comunicación de riesgo químico en el área petroquímica de Tarragona. 4.- Resultados Genéricamente se pueden observar algunas conclusiones: • Que en las áreas donde no se llevan a cabo iniciativas de comunicación de riesgo, la percepción del mismo es desequilibrada, se produce rechazo a la actividad química en su conjunto y todos los sectores de la sociedad se ven afectados. • Que las estrategias comunicativas públicas (de la administración) responden cada vez en mayor grado, al cumplimiento de la legalidad vigente. • Que las iniciativas comunicativas del sector privado (asociaciones empresariales territoriales/empresas) responden mas bien a estrategias de relaciones públicas que a comunicación de riesgo, ya que hacen especial incidencia en temas de seguridad sin mencionar los riesgos que la hacen necesaria. • Que destacan algunas particularidades del polígono químico de Huelva respecto al resto, especialmente en cuanto a sensibilidad por las percepciones sociales. • Que el polígono petroquímico de Tarragona lidera a nivel del Estado Español las iniciativas en comunicación de riesgo, tanto en el ámbito público cómo en el privado. / At present we are subjected to situations that might be considered uncertain, so we learn to live with a new element, risk, that conditions and changes our perception of reality. The fundamental approach of this project is the importance of proper attention to the communicative dimension of risk in certain environments. 2. - Object of study This paper analyzes the communication of risk in the Spanish chemical industry. Thus, the object of study are the communicative practices of public and private organizations of geographical areas analyzed (Andalusia, Asturias, Cantabria, Catalonia and the Basque Country), and its comparative evaluation in terms of adaptation to the needs and expectations of the population. 3. - Methodology The methodology consists of several specific procedures: first a literature review including, newspaper articles and other documents to develop the theoretical and general fundamentals of the subject. Secondly empirical research through a field study based on document analysis techniques and in-depth interviews with the people in charge of communication management in at both companies and administrations of the select areas. (26 interviews). Third participant observation developed over more than 20 years of professional experience related to chemical risk communication in the petrochemical area of Tarragona. 4. - Results The following are the main conclusions of this research: • That in areas where risk communication initiatives are not carried out, the perception of it is unbalanced, chemical activity as a whole suffers from rejection and all sectors of society are affected. • That public communication strategies public administration is increasingly compliant with the law. • That communication initiatives of the private sector (territorial associations / companies) correspond rather to public relations strategies to risk communication, and they make special emphasis on safety and avoid mentioning the risks that make it necessary. • Some peculiarities of chemical Huelva polygon make it different from the rest, especially in terms of sensitivity of the social perceptions. • The Tarragona petrochemical area leads Spanish state level initiatives in risk communication in Spain, both in the public and private sectors. / De nous jours nous sommes soumis à des situations qui pourraient être considérées comme incertaines. Ainsi nous apprenons à vivre avec un nouvel élément, le risque qui conditionne et fait changer notre perception de la réalité. L'approche fondamentale de ce projet est l'importance de l'attention voulue à la dimension communicative dans certains environnements de risque . 2 -. Objet de l'étude Cette thèse de doctorat analyse la communication des risques dans l'industrie chimique espagnole. Ainsi, l'objet de l'étude sont les pratiques de communication des institutions publiques et privées des zones géographiques analysées (Andalousie, Asturies, Cantabrie, Catalogne et le Pays Basque), et son évaluation comparative en termes d'adaptation aux besoins et aux attentes de la population. 3 -. Méthodologie La méthodologie se compose de plusieurs procédures spécifiques: d'abord une recherche bibliographique, afin de développer les fondements théoriques et générales du sujet. Deuxièmement une recherche empirique à travers une étude de terrain sur la base de techniques d'analyse des documents et des entrevues en profondeur avec les gestionnaires de la communication des zones étudiées à la fois des entreprises et des administrations (26 entretiens). Troisième observation participante développée depuis plus de 20 ans d'expérience professionnelle liée à la communication des dangers chimiques dans la zone pétrochimique de Tarragone. 4 -. Résultats De manière générique, on peut remarquer les conclusions suivantes: • Que dans les zones où l’on ne réalise pas d’initiatives de communication des risques, la perception de celui-ci est déséquilibré, la population rejette l'activité chimique dans son ensemble et tous les secteurs de la société sont touchés. • Que les stratégies de communication de l’administration publique sont de plus en plus proches d’une droite application de la loi. • Que les initiatives de communication du secteur privé (associations territoriales / entreprises) répondent plutôt aux stratégies de relations publiques que à la communication des risques, car elles mettent un accent particulier sur la sécurité et ne mentionnent pas les risques qui la rendent nécessaire. • Certaines particularités de chimique de Huelva sont mises en évidence polygone du reste, notamment en termes de sensibilité des perceptions sociales. • Le pôle pétrochimique Tarragone mène des initiatives pionnières en Espagne en matière de communication des risques, à la fois dans les secteurs public et privé.

El risc com a concepte operatiu ha esdevingut en l'entorn global un concepte creixentment transversal. La seva visibilitat s'ha incrementat enormement per la circulació comunicativa dels discursos que li donen forma i significat. Més enllà del rol reconegut dels mitjans de comunicació, el caràcter constitutiu de la comunicació travessa les lògiques institucionals, científiques i ciutadanes. Aquest treball planteja, més enllà de les lògiques pràctiques i instrumentals, la comunicació social del risc com els processos en els quals la circulació de discursos participa en la seva definició, i les comunitats de comunicació e risc com un concepte a explorar. A mode de estudi de cas analitza la irrupció del canvi climàtic i la seva influència sobre els riscos nuclear i químic en l'entorn de la Unió Europea remarcant les potencialitats de la comunicació de risc com a disciplina pràctica reformulada a partir d'un enfocament pròpiament comunicatiu. / El riesgo como concepto operativo se ha convertido en el entorno global en un concepto crecientemente transversal. Su visibilidad ha incrementado enormemente a través de la circulación comunicativa de discursos que le dan forma y significado. Más allá del rol reconocido de los medios de comunicación, el carácter constitutivo de la comunicación atraviesa las lógicas institucionales, científicas y ciudadanas. Este trabajo plantea, más allá de su lógica práctica e instrumental, la comunicación social del riesgo como aquellos procesos en los cuales este es definido a través de la circulación de discursos, y las comunidades de comunicación de riesgo como un objeto a explorar. Como estudio de caso analiza la irrupción de cambio climático y su influencia sobre los riesgos nuclear y químico en el entorno de la Unión Europea, remarcando las potencialidades de la comunicación de riesgo como disciplina práctica reformulada a partir de un enfoque propiamente comunicativo. / Risk as an operational concept has become a cross-cutting concept into a global environment. Its visibility has greatly increased through the movement of communicative discourses that shapes it and gives meaning to it. Beyond the acknowledged role of the media, the constitutive nature of communication goes over the institutional, scientific and citizen logics. This research argues, beyond its practical and instrumental logics, the social communication of risk as those processes which it is defined by the circulation of discourses among risk communication communities as an object to explore. As a case study, it examines the emergence of climate change and its influence on nuclear and chemical risks in the European Union, highlighting the potentialities of risk communication as a practical discipline reformulated from a communicative approach.