The Cross Ambiguity Function (CAF) is often used for passive geolocation of an emitter based on the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) of the received signals. CAF performance has been thoroughly investigated in regards to traditional single-input single-output (SISO) signals. Little is known about how the CAF will respond to signals from multiple-input multiple-output (MIMO) systems which utilize multiple antennas. This thesis focuses on characterizing the CAF's magnitude distribution in order to determine the probability of correctly determining the correct TDOA/FDOA bin, and the resulting impact on geolocation. The received signals are studied in the presence of additive white Gaussian noise (AWGN) as well as multi-channel propagation effects such as phase ambiguities and offsets due to multi-antenna transmission. Two and four transmit antennas using either a form of spatial multiplexing or space-time block coding are the focus of this work because they are mostly commonly found in currently deployed communication systems. The effects of these transmit schemes are studied with respect to TDOA/FDOA error and the resulting position error. The analysis is performed using a detection theory framework as opposed to estimation theory in order to empha- size the impact of MIMO transmission on determining the correct TDOA/FDOA bin. A simple method using the CAF magnitude as a decision statistic is also presented so that TDOA/FDOA errors can be detected and filtered in an attempt to improve positioning estimates. / Master of Science

Det här examensarbetet utformas inom TBLT forskningsområdet, dvs. uppgiftsbaserad språkundervisning (Task-based Language Teaching) och utvecklingen av inlärares skriftliga målspråksperformans. TBLT-forskning har bevisat att kognitiv uppgiftskomplexitet manipulation har en tydlig påverkan på inlärares produktions. Detta visas i specifika aspekter i målspråksproduktionen. TBLT-forskning präglas dock av motstridiga studieresultat när det gäller hur den kognitiva manipulationen påverkar lingvistiska dimensioner. I syfte att undersöka effekten av uppgiftskomplexitets manipulation, presenteras detta examensarbete med empiriskt fokus på de lingvistiska dimensionerna korrekthet, komplexitet och flyt (CAF dimensions) i skolelevers skriftliga produktioner. Dessutom undersöker examensarbetet hur elevernas språkliga kompentens ytterligare kan påverka effekten av manipulationen. Examensarbetets bakgrund, diskussion och slutsats grundas på två teoretiska modeller, Cognition Hypothesis (Robinson, 2003, 2005, 2007) och Trade-off Hypothesis (Skehan, 1998, 2015). Dessa förklarar manipulationseffekten i uppgiftskomplexitet på olika och kontrasterande sätt. I detta examensarbete undersöks 72 svenska gymnasieelevers skriftliga produktioner i engelska genom två versioner (enkel vs. komplex) av en argumenterande uppgift. Resultaten visar att den komplexa versionen bara har få skillnader och inom dessa visas en större effekt i lexikalisk komplexitet. Manipulationen av uppgiftskomplexitet visar ytterligare större effekt bland elever med högre språklig kompetensnivå. Sådana resultat innefattar betydelsefulla pedagogiska tillämpningar för klassrummets praktik, för uppgiftsutformning och val, samt för lärares arbete.

Les travaux de cette thèse concernent l'étude de l'influence des conditions de dépôt sur la microstructure et les propriétés optiques de monocouches dans le but de réaliser des filtres optiques particuliers commercialisables. La méthode de dépôt utilisée est l'évaporation par canon à électrons avec assistance ionique. L'un des deux projets a été de vérifier la faisabilité de filtres optiques infrarouges dans la gamme [2-15] µm avec des matériaux non toxiques. Les monocouches des trois fluorures étudiées ont montré des comportements différents suivant les conditions de dépôt, notamment suivant la température du substrat qui influe fortement sur leur microstructure. L'association du BaF₂ au germanium, avec des réglages optimisés, montre pour différents filtres réalisés des résultats proches de la théorie. Ces filtres sont donc commercialisables. Le second projet a été de développer une machine de dépôt dans le but de pouvoir réaliser des filtres complexes d'une centaine de couches d'épaisseur variable (de 15 à 300 nm) associant des monocouches de TiO₂ à des monocouches de SiO₂. L'étude de l'influence des paramètres de dépôts (pression, assistance ionique, préchauffage du matériau) au travers différentes caractérisations (MEB, AFM, ellipsométrie)  a permis une optimisation des réglages de l'enceinte de dépôt plus efficace et adaptée en fonction des spécifications des filtres optiques à réaliser. Puis, une étude ellipsométrique poussée de l'indice de réfraction des monocouches de TiO₂ en fonction de leur épaisseur a conduit à une nette évolution des résultats pour la réalisation du filtre complexe. / This thesis deals the study of deposition conditions 'effect on the microstructure and optical properties of monolayers in order to achieve marketable optical filters, with particular specifications. All filters and monolayers were deposited by ion-assisted electron-beam evaporation technique. One of the two projects was to test the feasibility of infrared optical filters in the range [2-15] µm with non-toxic materials. The study of monolayers of three fluorides showed different behaviors depending on the deposition conditions especially as a function of the substrate temperature that affects their microstructure. For different filters realized, the association of BaF₂ with germanium, settings of deposition optimized, shows results close to the theory and these filters are marketable. The second project was to develop a deposition chamber in order to realize complex filters built with one hundred layers of variable thickness (15 to 300 nm) associating monolayers of TiO₂ with monolayers of SiO₂. The study of the influence of deposition parameters (pressure, ionic assistance, preheating of material) through different characterizations (SEM, AFM, ellipsometry) allowed the optimization of deposition's parameter settings more effective, and adapted according to the specifications of the optical filters to realize. Then, an ellipsometric advanced study of the refractive index of TiO₂ monolayers depending on their thickness led to a significant change in results for the realization of complex filter.

La réplication des chromosomes est altérée par les facteurs endogènes et/ou exogènes qui perturbent la progression des fourches de réplication. Les cellules doivent donc coordonner la synthèse d’ADN avec des mécanismes assurant la stabilité et le rétablissement des fourches bloquées. La recombinaison homologue (RH) est un mécanisme universel qui permet la réparation de l’ADN et participe au maintien de la réplication des chromosomes. Néanmoins, les mécanismes qui régulent la RH, notamment la RH ectopique versus la RH allélique, restent mal compris. Un autre mécanisme essentiel assurant la stabilité des génomes est l’assemblage de l’ADN néo-synthétisé autour de nucléosomes, conduisant à la constitution de fibres chromatiniennes nécessaires à l’organisation structurale du matériel génétique. Chez Saccharomyces cerevisiae, des défauts d’assemblage de la chromatine conduisent à une instabilité des fourches de réplication et augmentent le taux de RH. Sachant que les chaperonnes d’histones jouent un rôle crucial durant l’assemblage de la chromatine, j'ai décidé de me concentrer sur le rôle de la chaperonne d’histones H3-H4 appelé Chromatin Assembly Factor 1 (CAF-1) dans les mécanismes de RH, chez Schizosaccharomyces pombe. En effet, la RH est associée à une étape de synthèse de l’ADN, et peu de choses sont connues sur l’assemblage de la chromatine au cours de cette synthèse. Mes résultats ont exclu un rôle de CAF-1 dans la recombinaison allelique et le maintien de la stabilité des fourches de réplication. Par contre, CAF-1 joue un rôle important dans les mécanismes de recombinaisons ectopique et dans la formation de réarrangements chromosomiques induits par des blocages de fourches. Mes données suggèrent un modèle selon lequel CAF-1 permet la stabilisation d’intermédiaires de recombinaison précoces (D-loop), via le dépôt de nucleosomes au cours de l’extension par polymérisation de ces intermédiaires. Ainsi CAF-1 neutralise la dissociation des intermédiaires de recombinaison précoces par l’ADN helicase Rqh1. CAF-1 ferait partie d'un équilibre qui règle la stabilité/dissociation des intermédiaires de recombinaison précoces. J'ai montré que le rôle de CAF-1 dans cet équilibre a une importance toute particulière pendant la recombinaison non-allelique, révélant ainsi un nouveau niveau de régulation des mécanismes de RH par l'assemblage de la chromatine. / The replication of chromosomes can be challenged by endogenous and environmental factors, interfering with the progression of replication forks. Therefore, cells have to coordinate DNA synthesis with mechanisms ensuring the stability and the recovery of halted forks. Homologous recombination (HR) is a universal mechanism that supports DNA repair and the robustness of DNA replication. Nonetheless, mechanisms regulating HR pathways, such as ectopic versus allelic recombination, remain poorly understood. Another essential pathway for genome stability is the wrapping of newly replicated DNA around nucleosomes, leading to the constitution of a chromatin fibre, which allows the structural organization of the genetic material. In Saccharomyces cerevisiae, deficiencies in chromatin assembly pathways lead to replication forks instability and consequent increase in the rate of HR. Histone chaperones play a crucial role during chromatin assembly, thus I decided to focus on the H3-H4 histone chaperone Chromatin Assembly Factor 1 (CAF-1), to study its role in HR processes in Schizosaccharomyces pombe. Indeed, HR includes a DNA synthesis step and little is known about the associated chromatin assembly. My data excluded a role for CAF-1 in allelic recombination and in the maintenance of forks stability. However, CAF-1 was found to play an important role during ectopic recombination, in promoting chromosomal rearrangements induced by halted replication forks. My data support a model according to which CAF-1 allows the stabilization of early recombination intermediates (D-loop), via nucleosome deposition during the elongation of these intermediates. Doing so, CAF-1 counteracts the dissociation of early recombination intermediates by the helicase Rqh1. Therefore, CAF-1 appears to be part of an equilibrium that regulates stability/dissociation of early steps of recombination events. Importantly, I found that the role of CAF-1 in this equilibrium is of particular importance during non-allelic recombination, revealing a novel regulation level of HR mechanisms and outcomes by chromatin assembly.

Ptf1a/p48 is a pancreas specific bHLH transcription factor that is required at early stages of embryonic development for pancreas formation and, during adulthood, for the proper exocrine pancreatic function. P48 also exerts an antiproliferative effect, which may exert a tumor suppressor activity. In this study, based on a yeast two-hybrid approach, we have identified new p48 partners that modulate the activity of p48. Among the newly identified putative interactors we found p/CAF, which is a coactivator that potentiates its transcriptional activity, and ICAT, an inhibitor of the β-catenin/TCF signaling pathway. ICAT binds to p48 and is coexpressed with it in the pancreas during development and postnatally. Using different cellular models, ICAT overexpression in acinar tumor cells resulted in changes of the pancreatic specific gene expression pattern. Furthermore, high levels of ICAT inhibited the interaction between p48 and p/CAF. While this hetero-oligomeric complex is required for the acinar gene expression, ICAT itself is shown to be present in a reconstituted PTF1 complex in vivo. Importantly, altered ICAT expression is demonstrated in several histological types of pancreatic tumors, possibly contributing to their differentiation phenotype and neoplastic properties. / Ptf1a/p48 es un factor de transcripción bHLH específico del páncreas necesario durante los estadios tempranos del desarrollo embrionario para la formación del mismo, y para el correcto funcionamiento del páncreas exocrino en el adulto. P48 desempeña también una función antiproliferativa, la cual puede resultar en una actividad de supresión tumoral. En el presente estudio, basado en una estrategia de cribado de doble-híbrido en levadura, han sido identificadas nuevas proteínas que interaccionan y que modulan la actividad específica de p48. Entre las posibles proteínas que interaccionan y han sido identificadas de novo se encuentra p/CAF, un co-activador que potencia la actividad transcripcional de p48, y ICAT, un inhibidor de la vía de señalización de la β-catenina. Se ha demostrado que ICAT se une a p48 y ambos son co-expresados en el páncreas durante el desarrollo y en el adulto. Utilizando diferentes modelos celulares, la sobreexpresión de ICAT en células tumorales acinares resultó en un cambio en el patrón de expresión de genes específicos del páncreas. Al mismo tiempo, se observó que niveles elevados de ICAT inhiben la interacción entre p48 y su co-activador p/CAF. Mientras que este complejo hetero-oligomérico es necesario para la expresión de los genes acinares, se demostró que ICAT está presente en un complejo PTF1 reconstituido in vivo. Finalmente, se observaron alteraciones en la expresión de ICAT en varios tipos histológicos de tumores pancreáticos, que posiblemente contribuyen a su fenotipo de diferenciación y propiedades neoplásicas.

Le rôle fonctionnel des transcrits de l’hétérochromatine péricentromérique reste à ce jour largement incompris chez les eucaryotes supérieurs. Néanmoins, il a été montré que ces transcrits sont soumis à un contrôle très précis, fonction du cycle cellulaire. La régulation de la transcription est fortement contrôlée par la structure de la chromatine qui peut être modifiée localement en changeant la composition biochimique du nucléosome, notamment par l’utilisation des variantes d’histones. L’objectif de ma thèse a été de mieux comprendre le rôle de la protéine chaperonne d’histone DAXX et de sa variante d’histone H3.3 dans la régulation de la transcription des séquences répétées péricentromériques. Par la méthode de purification TAP-TAG, les partenaires spécifiques de DAXX ont été identifiés à partir d’extraits solubles nucléaires de fibroblastes embryonnaires murins. Ces analyses ont mis en évidence que CAF-1, classiquement associé à H3.1, et les facteurs de remodelage de la chromatine ATRX et CHD4 interagissent spécifiquement avec DAXX. Le rôle de ces protéines dans le contrôle de la transcription de l’hétérochromatine péricentromérique a ensuite été mis en évidence par une approche combinant l’interférence ARN et la Q-PCR. Enfin, les résultats suggèrent fortement que ces mécanismes de régulation ont lieu au niveau des corps nucléaires PML. L’ensemble de ces données montre qu’il existe une régulation spatio-temporel très fine de la structure de la chromatine régulant la transcription de l’hétérochromatine péricentromérique. / The functional role of pericentromeric heterochromatin transcripts remains largely unknown in higher eukaryotes. Nevertheless, it has been shown that these transcripts are subject to very precise control, depending on the cell cycle. Regulation of transcription is tightly controlled by chromatin structure that can be modified locally by changing the biochemical composition of the nucleosome, including the use of histone variants. The aim of my thesis was to better understand the role of the histone chaperone protein DAXX and its histone variant H3.3 in the regulation of transcription of pericentromeric repeats. By the method of TAP-TAG purification, DAXX specific partners were identified from soluble nuclear extracts of murine embryonic fibroblasts. These analyzes revealed that CAF-1, classically associated with H3.1, and the chromatin remodeling factors, ATRX and CHD4, specifically interact with DAXX. The role of these proteins in the control of transcription of pericentromeric heterochromatin was then highlighted by an approach combining RNAi and Q-PCR. Finally, the results strongly suggest that these regulatory mechanisms take place at PML nuclear bodies. Taken together, these data show that there is a spatio-temporal regulation of the fine structure of chromatin regulates transcription of pericentromeric heterochromatin.

and Key Words The linguistic concept of complexity as a component of the CAF triad is used to describe the complexity of texts, either spoken (transcribed) or written, and to describe speaker advancedness not only in L1, but also in L2 research. On the most basic level, lexical complexity and syntactic complexity can be distinguished, however, complexity is a multidimensional concept and many different descriptions and operationalisations exist; there is an even wider gap in terms of measuring lexical complexity of L2 oral speech with lexical frequency wordlists as studies on lexical sophistication have yielded inconsistent and sometimes inconclusive results; the majority of studies on lexical sophistication, one of the subdivisions of lexical complexity, have been carried out on written learner production. For this reason, this thesis focuses on measuring lexical complexity in L2 speech with word frequency lists; more specifically, it presumes that C1 speakers would produce more of complex vocabulary (low-frequency vocabulary) than B2 speakers in our sample; this thesis also attempts to correlate word frequency list results with English Vocabulary Profile results and compare the individual speakers. For this analysis 10 B2 and 10 C1 Czech speakers of English were selected from the LINDSEI spoken...

Made available in DSpace on 2016-04-28T14:58:38Z (GMT). No. of bitstreams: 1 2001 - Claudia de Souza.pdf: 251955 bytes, checksum: b69d1d8a6093e5f84e1aeb625a7a998e (MD5) Previous issue date: 2001-02-16 / The objective of this research was to study the relationship between non-conventional, or agroecological coffee production management and the quality of the product. This was a demand of the Association of Small Coffee Producers of Po?o Fundo, Minas Gerais State, Brazil. Six small farms were studied between the months of May and September 1996. Surveys were applied to farmers to find out about the main agricultural practices used by their coffee production. The following chemical and qualitative analyses were performed on the coffee drink from the studied areas: phenolics, poliphenoloxidases, color index and titrable acidity. Macro and micronutrients contents on coffee leaves and soil nutrient levels were evaluated. In addition, visual analysis was also carried out to assess the symptoms of leaf miner caused by Leucoptera coffeella Gu?rin-M?neville & Perrottet, 1842 Lepdoptera: Lyonetiidae (bicho-mineiro) and syndrome of caused by Phoma sp. The farms were typified according to the level of use of practices considered as agroecological or conventional. The results were analyzed by principal component analyses followed by cluster analyses. Two out of the six farms that used the most agroecological practices, formed a distinct group characterized by coffee drink of better quality. However, regarding soil fertility variables, a cluster was formed due to soil acidity. One of the farms using the most agroecological practices, clustered by itself for its lower soil pH, higher exchangeable Al+3 levels and lower Ca+2 levels. The variables related to leaf nutrient levels, were responsible for clustering farms with higher levels of agroecological practices. In this case, clustering took place by the lower levels of leaf S and B and higher levels of Ca and Mg. Also a trend of lower levels of leaf micronutrients on those properties was found. As a recommendation, more attention should be given to soil acidity and micronutrient replacement on those farms. Also, the agroecological practices used by the farms should be studied further since they resulted in better coffee quality. / O objetivo desse estudo foi estudar a rela??o entre o manejo n?o convencional, ou agroecol? gico e a qualidade da bebida de caf?, como resposta a demanda apresentada pela Associa??o de Pequenos Produtores de Po?o Fundo. Seis propriedades foram estudadas entre os meses de maio e setembro de 1996. Entrevistas semi-estruturadas foram aplicadas com objetivo de se conhecer o manejo efetuado nas lavouras de caf?. Foram realizadas an?lises qu?micas qualitativas da bebida do caf? nas ?reas amostradas quanto aos fen?licos totais, polifenoloxidase, ?ndice de cor e acidez titul?vel. Levantamento nutricional das propriedades tamb?m foram efetuados tanto no que diz respeito a an?lises foliares quanto de fertilidade do solo. Al?m disso, foi realizada a observa??o visual quanto ? incid?ncia de sintomas relacionados ? Leucoptera coffeella Gu?rin-M?neville & Perrottet, 1842 Lepdoptera: Lyonetiidae (bicho- mineiro) e da s?ndrome da seca de ponteiros, associados a Phoma sp. As propriedades foram tipificadas quanto ao grau de utiliza??o de pr?ticas consideradas como agroecol?gicas ou convencionais . Os resultados foram analisados por meio de an?lise de componentes principais, seguida de an?lise de conglomerados (clusters) indicaram que as duas propriedades que utilizavam o maior n?mero de pr?ticas agroecol?gicas formaram um grupo distinto, caracterizado por uma qualidade de bebida considerada superior ?s demais. Quanto ?s vari?veis de fertilidade do solo, observou-se um agrupamento relacionando ? acidez do solo; uma propriedade que utilizando o maior n?mero de pr?ticas agroecol?gicas se diferenciou das demais por formar um cluster na regi?o de baixa acidez no solo (pH mais elevado e menor teor de Al troc?vel), bem como menor teor de Ca. As vari?veis de teores foliares tamb?m separaram as duas propriedades de maior uso de pr?ticas agroecol?gicas das demais. Neste caso, a separa??o se deu devido aos menores teores de S e B e uma tend?ncia de maiores teores de Ca e Mg foliares. Os resultados indicam que, apesar do baixo uso de insumos industrializados, a boa qualidade da bebida foi mantida nas duas propriedades de maior grau de uso de pr?ticas agroecol?gicas , embora a acidez do solo estivesse alta (em uma das duas propriedades). H? uma tend?ncia de teores de alguns micronutrientes mais baixos nos cafeeiros dessas propriedades. Assim, como recomenda??es preliminares visando ? melhoria dos cafezais da regi?o estudada, uma maior aten??o deve ser dada aos aspectos de acidez do solo e restitui??o de S e B como tamb?m, as pr?ticas usadas na propriedade considerada como de maior uso de pr?ticas agroecol?gicas devem ser mais estudadas, pois, segundo este estudo relacionam-se a uma melhor qualidade de bebida de caf?.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2018-08-20T12:37:22Z No. of bitstreams: 1 2010 - Raquel Duarte da Costa Cunha Bandeira.pdf: 1478855 bytes, checksum: f7637b4df6dd802e4e0003f4fb48d8cd (MD5) / Made available in DSpace on 2018-08-20T12:37:22Z (GMT). No. of bitstreams: 1 2010 - Raquel Duarte da Costa Cunha Bandeira.pdf: 1478855 bytes, checksum: f7637b4df6dd802e4e0003f4fb48d8cd (MD5) Previous issue date: 2010-09-24 / Coffee is an extremely complex food matrix and has an important role in the world?s economy, especially in producing and exporting countries like Brazil. However this product may suffer from technical barriers imposed for exportation because of the possible presence of ochratoxin A, which is nefrotoxic and carcinogenic mycotoxin found in many foods including coffee. The aim of this study was to implement chemical metrology concepts in the development and validation of Liquid Chromatography with Mass Spectrometry in tandem (CLAE-EM/EM) method for identification and quantification of ochratoxin A in green and roasted coffee estimating uncertainty of measurement according to directive 2002/657/EC and Inmetro guidelines (DOC-CGCRE-2010). The extraction method was based on Pittet (1998) and chromatographic parameters were: flow rate of 0.3 mL/min, mobile phase 80:20 water trifluoracetic acid 0.05 %: methanol trifluoracetic acid 0.05 %, injection volume of 50 PL, injection mode Full loop, isocratic mode. The column was Synergi Hydro C18. The mass spectrometry parameters were optimized and transitions selected based on the colision energies monitored were m/z 404 >358 (-10.5 V) and m/z 404 >239 (-20.5 V). From the validation procedure, methods were considered seletive. The evaluation and verification of matrix effect was performed by comparing variances and averages using F and t test. Value of Fcalculated for green coffee (25.2152) and roasted coffee (104.0353), were higher than Ftable (4.0426). Value of t calculated for green (5.0214) and roasted coffee (10.1997) were higher than ttable (2.0106). Both methods were considered linear in the working range of calibration curve with linear correlation coefficients (r) of 0.98188 and 0.91754 for green and roasted coffee, respectively.The quantification and detection limits were 1.2 Pg/kg and 3.0 Pg/kg; 0.36 Pg/kg and 1.0 Pg/kg, for green and roasted coffee respectively. The average recoveries, RSDr and RSDR were in range of 90.45 ? 108.81 %, 5.39 ? 9.94 % and 2.20 ? 14.34 % for green coffee and 89.02 ? 108.85 %, 2.43 ? 13.73 % and 12.57 ? 17.84 % for roasted coffee. All results obtained were considered within acceptable levels according to literature. Measurement value and expanded uncertainties (U) for ochratoxin A were mass fraction w = (11.50 ? 1.11) and w = (4.63 ? 0.63) for green coffee and roasted coffee. Both methods developed and validated using a high sensitivity technique, that allowed detection, confirmation and quantification of ochratoxin A in green and roasted coffee with a estimated uncertainty of measurement, and in the future these methods can be used to help overcome possible technical barriers imposed for exportation of Brazilian coffee. / O caf? constitui uma matriz extremamente complexa e tem importante papel na economia mundial, especialmente nos pa?ses produtores e exportadores como o Brasil. No entanto tem sido alvo de barreiras t?cnicas devido a uma subst?ncia denominada ocratoxina A, micotoxina potencialmente nefrot?xica e nefrocarcinog?nica encontrada em muitos alimentos inclusive o caf?. O presente trabalho tem como objetivo implantar os conceitos da metrologia qu?mica no desenvolvimento, e valida??o do m?todo para identifica??o e quantifica??o de ocratoxina A no caf? verde e caf? torrado estimando a incerteza da medi??o e utilizando a t?cnica de Cromatografia L?quida acoplada a Espectrometria de Massas em s?rie (CLAE-EM/EM) seguindo os crit?rios da diretiva EC-657/2002 e o documento orientativo do Inmetro (DOCCGCRE- 2010). A metodologia de extra??o baseou-se em Pittet (1998) e os par?metros cromatogr?ficos foram: fluxo de 0,3 mL/min, fase m?vel 80:20 ?gua ?cido trifluoroac?tico 0,05%: metanol ?cido trifluoroac?tico 0,05 %, volume de inje??o de 50 PL, com o modo de inje??o Full loop e sistema de elui??o isocr?tico. A coluna utilizada foi Synergi Hydro C18. As condi??es do espectr?metro de massas foram otimizadas e a transi??o selecionada de acordo com suas energias de colis?o foram m/z 404 >358 (-10,5 V) e m/z 404 >239 (-20,5 V). A partir da valida??o os m?todos propostos foram considerados seletivos, a avalia??o e comprova??o do efeito matriz foi realizada atrav?s da compara??o das vari?ncias e das m?dias atrav?s do teste F e teste t. O Fcalculado para o m?todo caf? verde (25,2152) e caf? torrado (104,0353), apresentaram valores maiores que o Ftabelado (4,0426). O tcalculado para o caf? verde (5,0214) e torrado (10,1997) apresentaram valores superiores ao ttabelado (2,0106). Os m?todos foram considerados lineares em toda a faixa de trabalho da curva de calibra??o com os coeficientes de determina??o linear (r) de 0,98188 e 0,91754 para matriz caf? verde e caf? torrado, respectivamente. O limite de quantifica??o e detec??o para os m?todos propostos foram de 1,2 Pg/kg e 3,0 Pg/kg para caf? verde e 0,36 Pg/kg e 1,0 Pg/kg para caf? torrado. Os valores das recupera??es m?dias, DPRr e DPRR variaram na faixa de 90,45 - 108,81 %, 5,39 - 9,94 % e 2,20 - 14,34 % para caf? verde; e de 89,02 - 108,85 %, de 2,43 - 13,73 % e 12,57 - 17,84 %, para caf? torrado. Todos os resultados obtidos encontram-se dentro dos limites comumente aceit?veis na literatura. Todos os resultados de medi??o e as incertezas expandidas (U) para ocratoxina A foram as fra??es m?ssicas W = (11,50 ? 1,11) Pg/kg e W = (4,63 ? 0,63) Pg/kg para caf? verde e caf? torrado, respectivamente. Os m?todos desenvolvidos e validados utilizaram t?cnica de elevada sensibilidade, permitindo a detec??o, confirma??o e a quantifica??o de ocratoxina A no caf? verde e caf? torrado com c?lculo da incerteza, podendo auxiliar futuramente na supera??o das barreiras t?cnicas para exporta??o do caf? brasileiro.

Kent Fredholm (2015). Eleverna, datorn och språket: Studier av skoldatoriseringens effekter på elevers attityder, skrivstrategier och textproduktion i spanskundervisningen på gymnasiet. (The Pupils, the Computer and the Language: Studies of the Effects of School Computerisation on Pupils’ Attitudes. Writing Strategies and Written Text Production in Upper Secondary School Spanish Classes.) Stockholm University, Studies in Language Education 12. ISBN 978-91-7649-090-7. Written in Swedish, English and Spanish with abstracts in the three languages and a summary in English. The present work is based upon three studies performed between 2012 and 2014 at the Swedish upper secondary school with pupils studying Spanish as a foreign language. The first study investigates through lesson diaries and an online survey the pupils’ attitudes towards and perceptions of computer use in language learning at large, and specifically of online grammar exercises as compared to paper-based exercises. The participating pupils showed mixed attitudes towards using online exercises for grammar practice, with high demands on websites’ design and user friendliness, as well as for the correctness and reliability of automated corrections. A majority preferred mixed teaching methods (including computer use, teacher-led explanations and the use of paper- and pen-based exercises, especially translation tasks). The major advantage of using computers was considered to be for essay writing and information search. The second study investigates how a group of pupils use online resources when writing essays in Spanish, focussing on their extensive use of online translation services such as Google translate. The writing strategies of these pupils with free access to the Internet are compared to the strategies of another group working without Internet access. The third study examines effects of the use of online translation on the language in the pupils’ essays. The texts written with online translation are compared to texts written without Internet access, but with access to printed dictionaries. Few statistically significant differences can be seen between the two groups. These concern grammatical and lexical complexity and accuracy. The most clear differences regard spelling and article/noun/adjective congruence (with higher degrees of accuracy among the users of online translation), and syntax (with fewer errors in the group writing without online translation). The grammatical complexity was also somewhat higher in the online translation group. As for fluency (text length) and complexity, differences can be correlated to the pupils’ proficiency in Spanish, whereas no such correlation can be seen regarding accuracy.