This thesis is a study of the synthesis of N-substituted di(2-thienylmethyl)acetamides.

A partire dalla pubblicazione del Saggio sul dono di Marcel Mauss gli antropologi si sono diffusamente occupati delle dinamiche relative allo scambio di doni e al carattere obbligatorio della corresponsione da parte del ricevente. Tuttavia, tra le varie tipologie di donazioni è emersa una forma molto particolare individuata dall’antropologa statunitense Annette Weiner che è tornata a indagare le società dell’Oceania, studiate a suo tempo da Bronislaw Malinowski, pubblicando nel 1992 un importante lavoro ad essa relativo. Si tratta di una forma di dono paradossale che riguarda i possessi inalienabili, beni che per definizione non dovrebbero essere ceduti e tuttavia, dal momento che la loro durata nel tempo supera quella dei detentori originari, devono essere necessariamente trasferiti. Ad essi si lega il paradosso, individuato dalla studiosa, di keeping-while-giving che ben esprime la caratteristica per cui su tali beni il detentore originario tende a mantenere il controllo nonostante essi vengano donati, consentendo dunque l’alienazione di possessi inalienabili. In una società come quella altomedievale nella quale i doni rivestono grande importanza emerge, tuttavia, uno strumento particolarmente sfuggente per alcune sue caratteristiche specifiche; si tratta del beneficium. Esso è tradizionalmente connesso al rapporto “vassallatico-beneficiario”, interpretato come una sorta di retribuzione per il servizio militare reso a un signore, e fino a qualche tempo fa associato intrinsecamente al concetto di “feudalesimo” che sul finire del secolo scorso è stato al centro di un acceso dibattito tra gli studiosi. Alla luce delle acquisizioni antropologiche ho cercato dunque di indagare il beneficium nell’Italia altomedievale con l’intento di comprendere in che misura esso si inserisca nelle dinamiche dello scambio di doni e in che termini possa essere ritenuto un “dono”, dal momento che dalle fonti indagate sembra aderire molto bene al paradosso descritto da Annette Weiner. Nella prima sezione della tesi vengono dunque ripercorsi i principali apporti antropologici e storiografici relativi al tema del dono, per spostare poi l’attenzione al tema specifico del beneficium richiamando le posizioni in merito degli studiosi tanto in ambito internazionale quanto in ambito specificamente italiano. La seconda sezione ruota attorno a quattro casi di studio scelti per condurre l’indagine sullo strumento beneficiario, costituiti da quattro grandi monasteri di fondazione regia nel regnum Italiae di tradizione longobarda che offrono corpora documentari continuativi e compatti. Proprio la storia dei singoli enti monastici ha permesso di definire il punto di partenza cronologico per l’indagine, vale a dire il secolo VIII quando tali enti vennero fondati, per situare il punto di arrivo nell’anno 924 con la morte dell’imperatore Berengario I, ultimo discendente di Carlo Magno per linea materna, che riuscì ad assumere il titolo imperiale. Attraverso la schedatura del patrimonio documentario dei singoli monasteri per il periodo preso in esame è stato dunque possibile rintracciare le occorrenze del termine beneficium per osservare le varie sfumature che di volta in volta esso assumeva. Il primo monastero indagato è S. Ambrogio di Milano, l’unico tra i quattro cenobi scelti per l’indagine ad essere fondato dopo la conquista franca di Pavia del 774, nato come creatura dell’arcivescovo per assumere nel corso del tempo un ruolo da protagonista di primo piano della vita cittadina. L’abbazia riuscì ad acquisire inoltre un immenso patrimonio fondiario tramite numerose donazioni, divenendo in alcuni momenti una sorta di mausoleo per alcuni sovrani carolingi che qui vi trovarono sepoltura. Il secondo caso di studio è rappresentato dall’abbazia di S. Maria di Farfa, che offre il patrimonio documentario più ricco di tutti i quattro casi indagati. Fondata agli inizi del secolo VIII supera per antichità gli altri tre monasteri oggetto di questo studio e consente di osservare un più nutrito dossier relativo allo strumento beneficiario, nel contesto regionale della Sabina e dell’Italia centrale. Il terzo caso di studio è costituito dal monastero di S. Silvestro di Nonantola fondato da Anselmo, cognato del re longobardo Astolfo, nel 752 su terreni di origine pubblica donati dal sovrano divenendo uno dei principali centri monastici del regnum Italiae. L’ultimo caso di studio è costituito dal cenobio femminile di S. Salvatore di Brescia, che agli inizi del secolo X avrebbe assunto la titolazione di S. Giulia, fondato dall’ultimo re longobardo, Desiderio, assieme alla moglie Ansa. Nato come monastero che secondo alcuni sarebbe stato pensato come un “mausoleo familiare”, attraversò momenti aurei tanto nei primi tempi quanto sotto i sovrani carolingi che, a partire dai primi decenni del secolo IX, ne affidarono l’amministrazione patrimoniale alle regine o alle principesse della loro dinastia. Dai quattro casi di studio è emerso un quadro molto variegato, che testimonia un uso dello strumento beneficiario diverso a seconda delle aree e dei contesti in cui gli enti indagati si trovavano ad essere inseriti, e non legato esclusivamente alla sfera militare come a lungo si è invece sostenuto. Si è tenuto conto, in tale sede, di tutte le sfumature del termine beneficium mettendo in risalto la convivenza, a fianco dell’istituto giuridico, del generico senso di “favore” che traspare principalmente dalle arengae dei diplomi dei vari sovrani. Nella terza e ultima sezione l’indagine è stata invece allargata all’intero regnum Italiae prendendo in considerazione varie tipologie di fonti a partire dagli inventari altomedievali che testimoniano il ricorso al beneficium da parte di enti monastici o episcopali per assegnare beni tratti dal loro patrimonio e che vanno ad affiancarsi ai polittici esplorati nel corso dell’analisi dei casi di studio monastici. L’osservazione dei capitolari carolingi relativi al regno italico ha permesso di indagare i capitoli di legge relativi al beneficium fornendo dunque un quadro della normativa ad esso relativa per poter operare un confronto con la “pratica” che emerge dai diplomi dei sovrani carolingi, da Carlo Magno a Berengario I, e dai conflitti sorti attorno all’uso dello strumento beneficiario testimoniati dai placiti. Infine, l’ultimo capitolo è dedicato alle fonti narrative, relative all’arco cronologico preso in esame, nelle quali è possibile riscontrare qualche riferimento al beneficium; si tratta della Historia di Andrea da Bergamo e dell’Antapodosis di Liutprando di Cremona. Da tali fonti emerge come il discorso sul beneficio ruoti attorno al tema della fidelitas e alla creazione di relazioni attraverso lo scambio di favori. Da tale varietà di fonti ho cercato dunque di comprendere, alla luce dei contributi antropologici, in quali termini il beneficium possa inserirsi quale strumento di relazione nel contesto dello scambio di doni nel regno italico di tradizione longobarda.

The Linked Open Data (LOD) cloud is currently a primary source of background knowledge for tasks in a wide variety of domains and across many scientific fields. The structured nature and the usage of well-defined open standards make it convenient to contribute to and build upon. However, since the major part of the LOD is ultimately crowdsourced and mostly populated and updated manually, some of the content in the LOD can become stale, inconsistent and lack coverage. Social media, on the other hand, uniquely allow the real world events to be accurately reflected with little or no delay in the form of posts and profile updates. A major downside of this vibrant source of knowledge that is contained in the social media is its lack of structure, significant noisiness and restrictive APIs that make it hard to extract, analyze and use it in the downstream tasks. In this thesis, I present the task of linking entities in a knowledge base (KB) to the corresponding social media profiles as an attempt to bridge the structured LOD cloud and the vibrant social media. As will be shown, such linking allows knowledge transfer between the two worlds: on the one hand, enabling the Semantic Web practitioners to harvest this vast amount of valuable, up-to-date data from the social media; on the other hand, the social media researchers can use the structured LOD knowledge much more efficiently, simplifying the pipelines and improving performance for tasks such as Type Prediction, Entity Linking, and User Profiling. I implement such knowledge transfer using DBpedia as a KB, since it is a cornerstone dataset in the LOD, and Twitter as a social media, due to its popularity and relative accessibility. However, approaches developed here are designed to be general and could be applied to other social media and KBs. To this end, firstly, I introduce SocialLink - a project designed to link KBs to social media profiles. SocialLink consists of (i) a linking approach that is able to produce high-quality entity-profile pairs, (ii) a LOD-compliant dataset of alignments between DBpedia and Twitter, (iii) the Social Media Toolkit system providing additional functionality on top of SocialLink. SocialLink employs a custom deep neural network-based architecture designed to efficiently exploit many modalities of data representing entities and profiles within DBpedia and Twitter. In second, I demonstrate how SocialLink can facilitate tasks in both Semantic Web and Social Media Analysis. In particular, I employ the abovementioned knowledge transfer to achieve state-of-the-art performance in Type Prediction task on DBpedia. Additionally, SocialLink is used to infer user interests on Twitter and to implement a novel approach that I proposed to prevent such inference. Finally, the Entity Linking capabilities of SocialLink are exploited to augment the social media management application called Pokedem and to provide an additional performance boost to a conventional Entity Linking pipeline achieving the second-best performance in EVALITA 2016 competition.

Languages are well known to be diverse on all structural levels, from the smallest (phonemic) to the broadest (pragmatic). We propose a set of formal, quantitative measures for the language diversity of linguistic phenomena, the resource incompleteness, and resource incorrectness. We apply all these measures to lexical semantics where we show how evidence of a high degree of universality within a given language set can be used to extend lexico-semantic resources in a precise, diversity-aware manner. We demonstrate our approach on several case studies: First is on polysemes and homographs among cases of lexical ambiguity. Contrarily to past research that focused solely on exploiting systematic polysemy, the notion of universality provides us with an automated method also capable of predicting irregular polysemes. Second is to automatically identify cognates from the existing lexical resource across different orthographies of genetically unrelated languages. Contrarily to past research that focused on detecting cognates from 225 concepts of Swadesh list, we captured 3.1 million cognate pairs across 40 different orthographies and 335 languages by exploiting the existing wordnet-like lexical resources.

Reliability is one of the important issues of recent microprocessor design. Processors must provide correct behavior as users expect, and must not fail at any time. However, unreliable operation can be caused by excessive supply voltage fluctuations due to an inductive part in a microprocessor power distribution network. This voltage fluctuation issue is referred to as inductive or di/dt noise, and requires thorough analysis and sophisticated design solutions. This dissertation proposes an automated stressmark generation framework to characterize di/dt noise effect, and suggests a practical solution for management of di/dt effects while achieving performance and energy goals. First, the di/dt noise issue is analyzed from theory to a practical view. Inductance is a parasitic part in power distribution network for microprocessor, and its characteristics such as resonant frequencies are reviewed. Then, it is shown that supply voltage fluctuation from resonant behavior is much harmful than single event voltage fluctuations. Voltage fluctuations caused by standard benchmarks such as SPEC CPU2006, PARSEC, Linpack, etc. are studied. Next, an AUtomated DI/dT stressmark generation framework, referred to as AUDIT, is proposed to identify maximum voltage droop in a microprocessor power distribution network. The di/dt stressmark generated from AUDIT framework is an instruction sequence, which draws periodic high and low current pulses that maximize voltage fluctuations including voltage droops. AUDIT uses a Genetic Algorithm in scheduling and optimizing candidate instruction sequences to create a maximum voltage droop. In addition, AUDIT provides with both simulation and hardware measurement methods for finding maximum voltage droops in different design and verification stages of a processor. Failure points in hardware due to voltage droops are analyzed. Finally, a hardware technique, floating-point (FP) issue throttling, is examined, which provides a reduction in worst case voltage droop. This dissertation shows the impact of floating point throttling on voltage droop, and translates this reduction in voltage droop to an increase in operating frequency because additional guardband is no longer required to guard against droops resulting from heavy floating point usage. This dissertation presents two techniques to dynamically determine when to tradeoff FP throughput for reduced voltage margin and increased frequency. These techniques can work in software level without any modification of existing hardware. / text

O diguanilato cíclico (c-di-GMP) é uma molécula de sinalização intracelular que atua na regulação de importantes processos bacterianos como motilidade, formação de biofilme e virulência. As diguanilato ciclases (DGCs), contendo um domínio GGDEF ativo, catalisam a formação de c-di-GMP a partir de duas moléculas de GTP. A bactéria Xanthomonas citri subsp. citri (Xanthomonas axonopodis pv citri; Xac) é o agente causal do cancro cítrico, uma doença que ataca todas as variedades e espécies de citros. O genoma de Xac codifica 31 proteínas contendo domínios GGDEF. Treze destas proteínas possuem também domínios PAS e/ou GAF, que são ubíquos domínios sensores e de sinalização. Para tentar entender melhor o papel na sinalização por c-di-GMP das interações entre domínios GGDEF e domínios PAS e/ou GAF, estudos bioquímicos e funcionais foram realizados com as proteínas XAC0610 e XAC2446. XAC0610 contém um domínio GAF, quatro domínios PAS e um domínio GGDEF conservado. Análises fenotípicas com a linhagem nocaute XacΔ0610 mostraram que XAC0610 atua na regulação da motilidade e sobrevivência de Xac ao tratamento com H2O2. Ensaios de atividade enzimática demonstraram que XAC0610 é uma DGC cataliticamente ativa, e que a mutação sítio-dirigida de um resíduo conservado de lisina (Lys759) provoca uma grande redução na atividade de DGC. Os domínios GAF e PAS de XAC0610 aparentemente não atuam como domínios sensores, entretanto são importantes para a dimerização da proteína, necessária para a obtenção de altos níveis de atividade de DGC. Além disso, várias observações sugerem que XAC0610 não é submetida à inibição alostérica pelo produto, um mecanismo regulatório comumente utilizado para o controle da atividade de DGC. Por outro lado, os dados de cinética enzimática de XAC0610HIS-35-880 revelaram um efeito de cooperatividade positiva para a ligação dos substratos, com uma constante de dissociação para a ligação da primeira molécula de GTP (K1) cerca de 3-5 vezes maior que a constante de dissociação para a ligação da segunda molécula de GTP (K2). A partir deste estudo, nós apresentamos um esquema cinético geral mais apropriado para as análises dos dados cinéticos de enzimas DGCs e propomos que a ligação cooperativa do substrato talvez possa desempenhar um importante papel na regulação in vivo da atividade de algumas DGCs, aumentando sua sensibilidade a pequenas variações nos níveis celulares de GTP. Outra proteína caracterizada neste trabalho, XAC2446 possui um domínio GAF e um domínio GGDEF que, ao contrário do domínio GGDEF de XAC0610, não deve apresentar atividade de DGC. Mesmo assim, análises funcionais mostraram que XAC2446 regula negativamente a formação de biofilme e positivamente a motilidade de Xac. Ensaios de duplo híbrido em leveduras identificaram que XAC2446 interage com XAC2897, contendo um domínio GGDEF potencialmente ativo, e XAC1185, contendo um domínio HD fosfohidrolase de (p)ppGpp. Alguns estudos indicam que altos níveis celulares de c-di-GMP e baixos níveis de (p)ppGpp podem ser necessários durante a formação de biofilme. XAC2446 talvez possa atuar como um inibidor da atividade enzimática de XAC2897 e XAC1185 e influenciar, indiretamente e antagonicamente, tanto os níveis celulares de c-di-GMP quanto de (p)ppGpp. / Cyclic di-GMP is a bacterial second messenger that regulates a range of functions, including cellular motility, biofilm formation and virulence. This molecule is produced from two GTP substrates by the activity of diguanylate cyclases (DGCs) containing a GGDEF domain. The phytopathogenic bacteria Xanthomonas citri subsp. citri (Xanthomonas axonopodis pv citri; Xac) causes citrus canker in a wide variety of citrus species. The Xac genome codes for 31 proteins with GGDEF domains. Thirteen of the 31 Xac GGDEF domain-containing proteins also possess PAS (Per-Arnt-Sim) or GAF (cGMP-specific phosphodiesterases, adenylyl cyclases and FhlA) domains that are ubiquitous signaling and sensory domains. In order to better understand the relationship between these commonly associated domains, biochemical and functional studies were carried out with the XAC0610 and XAC2446 proteins. XAC0610 is a large multi-domain protein containing one GAF domain, four PAS domains and one GGDEF domain. This protein has a demonstrable in vivo and in vitro diguanylate cyclase (DGC) activity. Analysis of a XacΔ0610 knockout strain revealed that XAC0610 plays a role in the regulation of Xac motility and resistance to H2O2. Site-directed mutagenesis of a conserved DGC lysine residue (Lys759 in XAC0610) resulted in a severe reduction in XAC0610 DGC activity. XAC0610 DGC activity was also impaired by removal of the N-terminal GAF and PAS domains, which are probably needed for proper protein dimerization. Furthermore, experimental and in silico analysis suggest that XAC0610 is not subject to allosteric product inhibition, a common regulatory mechanism for DGC activity control. Instead, steady-state kinetics of XAC0610 DGC activity revealed a positive cooperative effect of the GTP substrate with a dissociation constant for the binding of the first GTP molecule (K1) approximately three to five times greater than the dissociation constant for the binding of the second GTP molecule (K2). We present a general kinetics scheme that should be used when analyzing DGC kinetics data and propose that cooperative GTP binding could be a common, though up to now overlooked, feature of these enzymes that may in some cases offer a physiologically relevant mechanism for regulation of DGC activity in vivo. The other characterized protein, XAC2446, has a GAF domain and a degenerated GGDEF domain. Unlike XAC0610, XAC2446 should not present DGC activity. Nevertheless, functional analysis of XAC2446 demonstrated that it plays a role in the regulation of Xac motility and biofilm formation. A yeast two-hybrid screen identifies XAC2897 (a potentially active GGDEF domain-containing protein) and XAC1185 (a (p)ppGpp hydrolase) as specific binding partners of the XAC2446 protein. As indicated by studies in other bacteria, high cellular levels of c-di-GMP and low levels of (p)ppGpp may be both required for biofilm formation. It is possible that XAC2446 might have a role in the antagonistic regulation of c-di-GMP and (p)ppGpp cellular levels by acting as an inhibitor of both XAC2897 and XAC1185 enzymatic activities.

La Coscienza di Zeno é o romance de Italo Svevo mais bem elaborado em termos formais, ocupando um lugar entre as grandes obras do início do século XX. O autor constrói um romance propriamente moderno ao arquitetar uma narrativa que tem como princípio formal a ironia, vinculada à matriz romântica do conceito. É a partir do mecanismo irônico que o romance estabelece um jogo constante de contradições, ambiguidades e reconfigurações negativas que revelam suas limitações e suas falhas. Assim, a noção tradicional de romance é desconstruída e reelaborada formalmente, mediante um gesto negativo e autorreflexivo caro à literatura do início do século XX. La Coscienza di Zeno, apesar de inicialmente aspirar à configuração da totalidade do arco de uma vida, opera ironicamente durante seu percurso o oposto disso, ou seja, revela o caráter fragmentário da vida, cuja unificação total não é nada mais que uma falsa imagem. O realce irônico maior está no fato de que, ao desconstruir o romance como tal, e apontar para seu falso status, a obra reconquista a capacidade de configurar a realidade, negativamente. / La Coscienza di Zeno is Italo Svevos most elaborate novel, and deserves a place among the great works of the early 20th century literature. Svevos truly modern novel elects the irony as its formal principle. The ironical mechanism, linked to the romantic matrix of the concept, establishes a series of contradictions, ambiguities and negative reconfigurations which reveals the novels fails and limitations. Thus, the traditional notion of the novel as genre is deconstructed and formally re-elaborated, trough a negative and self-reflexive gesture dear to the tradition of the early 20th century literature. La Coscienza di Zeno aims initially to configure the totality of ones life, but its course ironically reveals the opposite, the fragmentary character of life, whose total unification is nothing but sham. The strongest ironic trace lies in the fact that its exactly through the novels critical deconstruction that Svevo´s work reconquers the capacity to represent, negatively, the reality.

Submitted by PPG Teologia (teologia-pg@pucrs.br) on 2017-11-28T18:16:01Z No. of bitstreams: 1 DISSERTA??O - LUIZ GUATURA DA SILVA NETO.pdf: 911341 bytes, checksum: 2d91bb4700788f95a52ca0023779c16b (MD5) / Rejected by Caroline Xavier (caroline.xavier@pucrs.br), reason: Devolvido devido ao orientador cadastrado na publica??o (Luiz Carlos Susin) estar diferente do orientador que consta no material PDF (?rico Jo?o Hammes). on 2017-12-04T13:38:35Z (GMT) / Submitted by PPG Teologia (teologia-pg@pucrs.br) on 2017-12-04T13:42:37Z No. of bitstreams: 1 DISSERTA??O - LUIZ GUATURA DA SILVA NETO.pdf: 911341 bytes, checksum: 2d91bb4700788f95a52ca0023779c16b (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-12-04T16:38:16Z (GMT) No. of bitstreams: 1 DISSERTA??O - LUIZ GUATURA DA SILVA NETO.pdf: 911341 bytes, checksum: 2d91bb4700788f95a52ca0023779c16b (MD5) / Made available in DSpace on 2017-12-04T16:40:56Z (GMT). No. of bitstreams: 1 DISSERTA??O - LUIZ GUATURA DA SILVA NETO.pdf: 911341 bytes, checksum: 2d91bb4700788f95a52ca0023779c16b (MD5) Previous issue date: 2017-09-27 / This research seeks to address the theme ?Ecumenical and Interreligious Dialogue for the Path to Peace?, seeks to discover it as the world advances in technology and continues to suffer the conflicts which is a lack of dialogue promoted. In the first chapter, we try to demonstrate a path that can promote peace and justice, so we go through Willian Carey's journey through proposals for the Week of Prayer for Christian Unity, an Edinburgh Conference in Scotland, not beginning and the various conferences held during the past tense. Subsequently, movements by the desire of Protestants in Latin America, there is no European ecumenism, reporting a vision of ecumenical dialogue within the European protest in Latin America and Brazil. In Brazil, we exposed the birth of the Pentecostal Movement from the Assembly of God, its expansions and schism in 1987, in Salvador/Bahia; An understanding of ecumenism within the Pentecostal Movement in conjunction with the General Convention of Assemblies of God in Brazil (CGADB) and a view of the amounts attached to the National Convention of Assemblies of God in Brazil (CONAMAD). We also discussed the creation of the World Council of Churches, the contribution and development of the Catholic-Lutheran dialogue to the document "Conflict in Communion" and preparations for the 500th anniversary of the Reformation. In the third chapter, we talk about ecumenism, from the decree of the Second Vatican Council Unitatis Redintegration and punctual updating from the Ecumenical Council. Already in the fourth chapter, we focused on a statement ?Nostra Aetate?, which deals with interreligious dialogue, emphasizing interreligious dialogue for the construction of peace. / Esta pesquisa procura discorrer sobre o tema ?Di?logo Ecum?nico e Inter-religioso para o caminho da paz?, procurando compreend?-lo ? medida que o mundo avan?a em tecnologia e continua sofrendo os conflitos que a falta de di?logo promove. No primeiro cap?tulo, procuramos demonstrar um caminho que pode promover a paz e a justi?a e, para isso, percorremos o percurso idealizado por Willian Carey, passando pelas propostas da Semana da Ora??o pela Unidade dos Crist?os, a Confer?ncia de Edimburgo, na Esc?cia, no in?cio do s?culo XX, e nas diversas confer?ncias ocorridas durante todo o s?culo passado. Posteriormente, caminhamos pelo desejo de os protestantes da Am?rica Latina serem inclu?dos no Ecumenismo europeu, relatando a vis?o do di?logo ecum?nico dentro do Protestantismo europeu, na Am?rica Latina e no Brasil. No Brasil, expusemos o nascimento do Movimento Pentecostal a partir da Assembleia de Deus, sua expans?o e cisma em 1987, ocorrido em Salvador/Bahia; a compreens?o acerca do Ecumenismo dentro do Movimento Pentecostal Assembleiano ligado ? Conven??o Geral das Assembleias de Deus no Brasil (CGADB) e a vis?o dos assembleianos ligado ? Conven??o Nacional das Assembleias de Deus no Brasil (CONAMAD). Ainda, abordamos a cria??o do Conselho Mundial de Igrejas, a contribui??o e o desenvolvimento do di?logo cat?lico-luterano at? o documento ?Do conflito ? comunh?o? e os preparativos para os 500 anos da Reforma. No terceiro cap?tulo, discorremos acerca do Ecumenismo, a partir do decreto do Conc?lio Vaticano II ?Unitatis Redintegratio? e da atua??o pontif?cia a partir do Conc?lio Ecum?nico. J? no quarto cap?tulo, enfocamos a declara??o ?Nostra Aetate?, que trata do di?logo inter-religioso, dando destaque ao di?logo inter-religioso para a constru??o da paz.

La recherche de molécules ayant une affinité spécifique pour un métal est à la base de nombreux procédés de récupération sélective. C’est le cas pour l’uranium extrait de site minier, et isolé à la suite de plusieurs étapes dont une extraction par solvant à partir d’un jus concentré d’acide sulfurique. Pour corriger certains inconvénients du procédé d’extraction actuel, le potentiel de nouvelles molécules chélatantes de l’uranium doit être déterminé. Ceci est possible par l’utilisation d’une méthode de criblage servant à comparer rapidement un grand nombre de molécules. A ce jour, aucune méthode n’existe pour tester efficacement le pouvoir complexant et la sélectivité de molécules vis-à-vis de l’uranium en milieux très acides. La méthode de criblage proposée dans ce travail est basée sur le suivi colorimétrique et spectrophotométrique de la réaction de compétition entre un complexe chromophore de référence Arsénazo III-UO₂²⁺ avec des ligands compétiteurs. Plusieurs ligands issus de 4 familles (hydrazides, di-hydrazones et (mono, bis)-phosphonates) ont été criblés. Ces tests, réalisés en mélange monophasique MeOH/H₂SO₄, ont permis de déterminer un ordre d’affinité des di-hydrazones selon la fonctionnalisation du « squelette di-hydrazones ». L’effet de substituants sur la coordination avec l’ion UO₂²⁺ a pu être reproduit par des calculs de modélisation moléculaire. D’autre part, une approche indépendante par spectrométrie de masse à ionisation électrospray a permis de retrouver cet ordre d’affinité et d’évaluer la sélectivité vis-à-vis du fer(III), élément souvent présent quantitativement dans les jus traités. La méthode de criblage, appliquée à des bis-phosphonates (en milieu aqueux H₂SO₄) déjà étudiés pour la décorporation de l’uranium en conditions biologiques, a mis en évidence des affinités remarquables, dont certaines inattendues. Ces résultats ont permis de montrer des relations entre les structures des molécules bis-phosphonates et leur efficacité de complexation. Avec cette nouvelle méthode de recherche, validée sur quelques familles moléculaires, de nouvelles pistes peuvent être envisagées pour le choix du design moléculaire, ou l’utilisation de molécules dans des procédés d’extraction innovants. / The search of molecules with a specific affinity for a metal is at the basis of many processes for selective recovery. This is the case for uranium that is extracted from mines, and isolated as a result of several steps among which a solvent extraction step from a concentrated juice of sulfuric acid. To overcome some drawbacks of the current extraction process, new chelating molecules of uranium must be determined. This is possible by using a screening method to quickly compare a large number of molecules. To date, there is no method to effectively test the complexing power and selectivity of molecules for uranium in highly acidic media. The screening method proposed in this work is based on ligand displacement reactions observed by UV-visible from the Arsenazo III-UO₂²⁺ reference complex where Arsenazo III is a chromogenic molecule displaying a strong affinity for uranium. Several ligands out of four molecular families (hydrazides, dihydrazones and (mono, bis)-phosphonates) were screened. These tests - carried out in monophasic MeOH/H₂SO₄ mixtures - provided an affinity order of di hydrazones related to the nature of functionalization of the "di-hydrazone skeleton". The effect of substituents on coordination with the UO₂²⁺ ion could be reproduced by DFT calculations (Density Functional Theory). Moreover, an independent approach by electrospray ionization mass spectrometry permitted to corroborate the affinity order and to evaluate the U(VI)/Fe(III) selectivity, as iron(III) is often found quantitatively in juices. The screening method applied to bis-phosphonate ligands (in H₂SO₄ aqueous medium), already studied for the in vivo removal of uranium in biological conditions, showed very strong uranophiles while some of them were unexpected. These results highlight relationships between the bis phosphonate structures and their complexation efficiency. With this new method of search, validated on some molecular families, new trails can be considered for the selection of molecular design or the use of innovative molecules in extraction processes.

Duccio’s Maestà, made between 1308 and 1311 for the high altar of Siena Cathedral, is one of the best-known works of medieval painting. Astoundingly complex, with dozens of individual fields and several narrative cycles, it measured around 15 feet or four meters square. It was, and long remained, the largest panel painting ever made. But why did its designers reach so far outside the bounds of normal altarpieces, and why did they stretch the media of panel painting to new heights? Replacing Duccio’s Maestà within its original Trecento context demonstrates that the altarpiece cannot be explained by either earlier Cathedral images or by earlier Marian panel paintings made for monastic churches, whose imagery the Maestà appropriated but drastically expanded. Instead, the creation of Duccio’s Maestà comes into clearer focus when understood in its original setting, the civic Cathedral. Santa Maria della Assunta comprised not just its particular physical space, but a political and economic one. Duccio’s Maestà interacted with the specific, material building, especially the Cathedral’s unique hexagonal crossing and its dense green-black and white stripes; both features may have contributed to a reading of the Maestà’s central Virgin as a symbol for Ecclesia, occupying her own Temple of Solomon. But the Maestà also crucially served as the backdrop to the city’s biggest annual holiday, the Feast of the Assumption. Though generally characterized by scholars as a unifying event, the Feast was in fact a means of social control, regulated by the state, where participation was enforced by law and on point of fine, and whose main event was the legally mandated presentation of candles to the Virgin in the Cathedral. Moreover, Duccio’s high altarpiece was commissioned during a troubled period: threatened by plotting nobles, and having steered the city through a sensitive election for a new bishop, the Government of the Nine was increasingly intent on regulating the Assumption Feast and the Cathedral’s commissioning body, the Opera del Duomo, which was largely funded through the wax donated on the Assumption. Confronted by unique pressures, Duccio and his unknown potential collaborators created unique solutions, contextualizing popular Marian imagery within the Cathedral’s theological and political concerns through the use of elaborate narrative cycles. Faced with the puzzle of fitting an entire image program onto a panel painting, Duccio privileged a coherent spatial setting, drawn largely through carefully-depicted architecture, that allowed him to keep figure size constant and that therefore to create a smooth spatio-temporal reading of the altarpiece; his arragement of the narrative scenes allowed for new meanings and cross-readings; Duccio further used different perspectival constructions to direct the viewer’s reading of the altarpiece. Duccio thus turned painting’s limitation, its lack of time, into a strength, showing new ways in which images could be deployed to interpret narrative; he also spurred a long conversation among artists on the very nature of their medium and what, exactly, it could accomplish: Within 40 years, four altarpieces, occasioned again by architecture, were commissioned for the Cathedral’s patronal altars. Located near to Duccio’s high altarpiece, these altarpieces would reflect their artists’ reception of Duccio’s Maestà. These radical works by Simone Martini and Lippo Memmi, Pietro and Ambrogio Lorenzetti, and Bartolommeo Bulgarini include the first narrative altarpiece and probably the first painting to pretend it is a view through a window in Western art. Above all, the patronal altarpieces demonstrate an interest in narrative, played out in the depiction of time and an attendant depiction of commensurate pictorial space.