A segmentação não-convencional de palavras em textos do ciclo II do ensino fundamental

This paper deals with unconventional segmentations of words in texts produced by students of the last four years of elementary school. The main hypothesis is that these data allow us to observe the characteristics of written and spoken utterances. Through analysis of data on prosodic constituents, we argue that students deal with (conflicting) hypotheses on the organization of unstressed syllables into prosodic constituents: metric feet, prosodic word and clitic group. We found evidence that unconventional spellings have their main motivation in the difficulty of students to assign the status of written word to grammatical items that are prosodic clitics.

Práticas de letramento/escrita em contexto da tecnologia digital

Artigo publicado na Eutomia: Revista Online de Literatura e Linguística Ano 3 Edição 1 Julho 2010 Seção: Destaques em Linguística.A revista é uma publicação do Departamento de Letras da UFPE.

A grafia dos erros de segmentação não-convencional de palavras

Neste trabalho, o foco de nossa reflexão é a grafia dos dados de escrita não-convencional de palavras, como ‘com tinuou’ e ‘ciesconder’. A questão que formulamos é: em que medida os erros de segmentação não-convencional também são resultados de decisões acerca da grafia das palavras? A resposta a essa questão é dada a partir da análise de erros de segmentação de palavras (tanto de hipossegmentação quanto de hipersegmentação) que ocorreram em textos produzidos por alunos que, à época da produção, cursavam a quinta série de uma escola pública da rede estadual de São Paulo. Os dados deste estudo foram extraídos de 107 textos produzidos a partir de uma mesma proposta de produção textual por alunos pertencentes a três turmas de quinta série. No total, foram identificadas 58 ocorrências de segmentação não-convencional, sendo 27 hipossegmentações, 28 hipersegmentações e 3 rasuras (quando há oscilação entre hipossegmentação e hipersegmentação de uma mesma palavra identificável por meio de algum elemento gráfico). Analisamos todas essas ocorrências de segmentação não-convencional, classificando-as como casos de hiper e hipossegmentação, buscando observar em que medida fatores de natureza ortográfica, juntamente com os de natureza prosódica, poderiam ser motivadores dessas grafias não-convencionais. Para fundamentar nossa resposta, ampliamos o conjunto de dados analisados às ocorrências de palavras que não estão ortograficamente corretas quanto à escolha de letras, mas que estão corretas quanto à segmentação convencional, como ‘emtão’. Ao consideramos a grafia das segmentações não-convencionais, observamos que as hipersegmentações de palavras que têm sílabas pretônicas ‘con’ e ‘en’ – como ‘com tinuou’, ‘com migo’, ‘com sigo’, e ‘em bora’, ‘en tão’, ‘em quanto’ – estão em parte motivadas no fato de essas sílabas poderem ser elementos funcionais – grafados como ‘com e ‘em’, respectivamente – e ainda no fato de, possivelmente, haver, por parte do escrevente, a observação de, pelo menos, duas regras ortográficas: uma que prevê que a letra ‘M’ só ocorre diante de ‘P, B’, dentro de palavra, e outra que prevê que a letra ‘M’ é a letra com que se grafam as preposições ‘com’ e ‘em’. Uma outra evidência de que há a formulação, por parte do aluno, de hipóteses conflitantes sobre a decisão quanto à grafia das palavras está no fato de ocorrer, em um mesmo texto, erros ortográficos relacionados à escolha entre ‘M’ e ‘N’, como ‘emtão’ e ‘en tão’. Vale observar que a grafia das nasais, particularmente em contexto de coda, oferece uma complexidade extra aos escreventes, desde o início do processo de alfabetização, como atestam os resultados de Chacon e Berti (2008), quando analisam dados de Educação Infantil. As ocorrências de hipossegmentação que envolvem o clítico ‘se’, como ‘ciesconder’, ‘cecasar’, chamam a atenção por serem grafadas com a letra ‘C’, que apresenta o valor de [s] somente quando seguida das letras ‘I’ e ‘E’, como em ‘cidade’ e ‘cebola’. Tem-se, pois, a consideração, por parte do aluno escrevente, de uma possibilidade de representação do sistema ortográfico. Assim, a flutuação na forma de grafar itens gramaticais pode ser interpretada como evidência de hipóteses do escrevente sobre o que seja palavra na escrita, particularmente, quando em jogo as formas dependentes (nos termos de CÂMARA Jr., 1970) ou os clíticos prosódicos (nos termos de BISOL, 2000). As hipóteses (conflitantes, por vezes) do que seja palavra na escrita – e que buscamos explicitar – são ancoradas, principalmente, em informações prosódicas, sobre o estatuto prosódico do clítico, e informações letradas, que dizem respeito à colocação de espaços em branco indicadores de palavra na escrita (que não se confunde com a palavra fonológica, nem com o grupo clítico) e à escolha de letras relacionadas às convenções ortográficas.

Hipersegmentações de palavra no ensino fundamental

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Large-Scale Population Analysis Challenges the Current Criteria for the Molecular Diagnosis of Fascioscapulohumeral Muscular Dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is a common hereditary myopathy causally linked to reduced numbers (<= 8) of 3.3 kilobase D4Z4 tandem repeats at 4q35. However, because individuals carrying D4Z4-reduced alleles and no FSHD and patients with FSHD and no short allele have been observed, additional markers have been proposed to support an FSHD molecular diagnosis. In particular a reduction in the number of D4Z4 elements combined with the 4A(159/161/168)PAS haplotype (which provides the possibility of expressing DUX4) is currently used as the genetic signature uniquely associated with FSHD. Here, we analyzed these DNA elements in more than 800 Italian and Brazilian samples of normal individuals unrelated to any FSHD patients. We find that 3% of healthy subjects carry alleles with a reduced number (4-8) of D4Z4 repeats on chromosome 4q and that one-third of these alleles, 1.3%, occur in combination with the 4A161PAS haplotype. We also systematically characterized the 4q35 haplotype in 253 unrelated FSHD patients. We find that only 127 of them (50.1%) carry alleles with 1-8 D4Z4 repeats associated with 4A161PAS, whereas the remaining FSHD probands carry different haplotypes or alleles with a greater number of D4Z4 repeats. The present study shows that the current genetic signature of FSHD is a common polymorphism and that only half of FSHD probands carry this molecular signature. Our results suggest that the genetic basis of FSHD, which is remarkably heterogeneous, should be revisited, because this has important implications for genetic counseling and prenatal diagnosis of at-risk families.

Non-linear magnetohydrodynamic simulations of density evolution in Tore Supra sawtoothing plasmas

The plasma density evolution in sawtooth regime on the Tore Supra tokamak is analyzed. The density is measured using fast-sweeping X-mode reflectometry which allows tomographic reconstructions. There is evidence that density is governed by the perpendicular electric flows, while temperature evolution is dominated by parallel diffusion. Postcursor oscillations sometimes lead to the formation of a density plateau, which is explained in terms of convection cells associated with the kink mode. A crescent-shaped density structure located inside q = 1 is often visible just after the crash and indicates that some part of the density withstands the crash. 3D full MHD nonlinear simulations with the code XTOR-2F recover this structure and show that it arises from the perpendicular flows emerging from the reconnection layer. The proportion of density reinjected inside the q = 1 surface is determined, and the implications in terms of helium ash transport are discussed. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4766893]

An integrated stratigraphic record of the Palaeocene-lower Eocene at Gubbio (Italy): new insights into the early Palaeogene hyperthermals and carbon isotope excursions

Terra Nova, 24, 380386, 2012 Abstract A high-resolution, integrated stratigraphic framework (stable isotope stratigraphy, standard calcareous nannofossil and foraminiferal biostratigraphy, magnetostratigraphy) together with geochemical and rock magnetic properties analyses of a complete and well-preserved succession at Contessa Valley (Gubbio, central Italy) have offered an excellent opportunity to identify and constrain the Palaeocene to early Eocene hyperthermals and carbon isotope excursions (CIEs). In addition, we provide the first evidence in the Tethys Ocean of CIEs, previously identified in the Pacific, Atlantic and Southern Oceans, highlighting their global significance and of some unknown CIEs. Their characteristics are compared with those reported for deep-sea cores and other land-based sections to test whether the signature associated with CIEs documented in our composite section might give evidence for tracing them over wider areas. The Contessa composite section thus represents a reference succession also for insight into the magnetobiochronostratigraphy and the magnitude of early Palaeogene hyperthermals and CIEs.

Structural changes and dynamic behaviour of vanadium oxide-based catalysts for gas-phase selective oxidations

Selective oxidation is one of the simplest functionalization methods and essentially all monomers used in manufacturing artificial fibers and plastics are obtained by catalytic oxidation processes. Formally, oxidation is considered as an increase in the oxidation number of the carbon atoms, then reactions such as dehydrogenation, ammoxidation, cyclization or chlorination are all oxidation reactions. In this field, most of processes for the synthesis of important chemicals used vanadium oxide-based catalysts. These catalytic systems are used either in the form of multicomponent mixed oxides and oxysalts, e.g., in the oxidation of n-butane (V/P/O) and of benzene (supported V/Mo/O) to maleic anhydride, or in the form of supported metal oxide, e.g., in the manufacture of phthalic anhydride by o-xylene oxidation, of sulphuric acid by oxidation of SO2, in the reduction of NOx with ammonia and in the ammoxidation of alkyl aromatics. In addition, supported vanadia catalysts have also been investigated for the oxidative dehydrogenation of alkanes to olefins , oxidation of pentane to maleic anhydride and the selective oxidation of methanol to formaldehyde or methyl formate [1]. During my PhD I focused my work on two gas phase selective oxidation reactions. The work was done at the Department of Industrial Chemistry and Materials (University of Bologna) in collaboration with Polynt SpA. Polynt is a leader company in the development, production and marketing of catalysts for gas-phase oxidation. In particular, I studied the catalytic system for n-butane oxidation to maleic anhydride (fluid bed technology) and for o-xylene oxidation to phthalic anhydride. Both reactions are catalyzed by systems based on vanadium, but catalysts are completely different. Part A is dedicated to the study of V/P/O catalyst for n-butane selective oxidation, while in the Part B the results of an investigation on TiO2-supported V2O5, catalyst for o-xylene oxidation are showed. In Part A, a general introduction about the importance of maleic anhydride, its uses, the industrial processes and the catalytic system are reported. The reaction is the only industrial direct oxidation of paraffins to a chemical intermediate. It is produced by n-butane oxidation either using fixed bed and fluid bed technology; in both cases the catalyst is the vanadyl pyrophosphate (VPP). Notwithstanding the good performances, the yield value didn’t exceed 60% and the system is continuously studied to improve activity and selectivity. The main open problem is the understanding of the real active phase working under reaction conditions. Several articles deal with the role of different crystalline and/or amorphous vanadium/phosphorous (VPO) compounds. In all cases, bulk VPP is assumed to constitute the core of the active phase, while two different hypotheses have been formulated concerning the catalytic surface. In one case the development of surface amorphous layers that play a direct role in the reaction is described, in the second case specific planes of crystalline VPP are assumed to contribute to the reaction pattern, and the redox process occurs reversibly between VPP and VOPO4. Both hypotheses are supported also by in-situ characterization techniques, but the experiments were performed with different catalysts and probably under slightly different working conditions. Due to complexity of the system, these differences could be the cause of the contradictions present in literature. Supposing that a key role could be played by P/V ratio, I prepared, characterized and tested two samples with different P/V ratio. Transformation occurring on catalytic surfaces under different conditions of temperature and gas-phase composition were studied by means of in-situ Raman spectroscopy, trying to investigate the changes that VPP undergoes during reaction. The goal is to understand which kind of compound constituting the catalyst surface is the most active and selective for butane oxidation reaction, and also which features the catalyst should possess to ensure the development of this surface (e.g. catalyst composition). On the basis of results from this study, it could be possible to project a new catalyst more active and selective with respect to the present ones. In fact, the second topic investigated is the possibility to reproduce the surface active layer of VPP onto a support. In general, supportation is a way to improve mechanical features of the catalysts and to overcome problems such as possible development of local hot spot temperatures, which could cause a decrease of selectivity at high conversion, and high costs of catalyst. In literature it is possible to find different works dealing with the development of supported catalysts, but in general intrinsic characteristics of VPP are worsened due to the chemical interaction between active phase and support. Moreover all these works deal with the supportation of VPP; on the contrary, my work is an attempt to build-up a V/P/O active layer on the surface of a zirconia support by thermal treatment of a precursor obtained by impregnation of a V5+ salt and of H3PO4. In-situ Raman analysis during the thermal treatment, as well as reactivity tests are used to investigate the parameters that may influence the generation of the active phase. Part B is devoted to the study of o-xylene oxidation of phthalic anhydride; industrially, the reaction is carried out in gas-phase using as catalysts a supported system formed by V2O5 on TiO2. The V/Ti/O system is quite complex; different vanadium species could be present on the titania surface, as a function of the vanadium content and of the titania surface area: (i) V species which is chemically bound to the support via oxo bridges (isolated V in octahedral or tetrahedral coordination, depending on the hydration degree), (ii) a polymeric species spread over titania, and (iii) bulk vanadium oxide, either amorphous or crystalline. The different species could have different catalytic properties therefore changing the relative amount of V species can be a way to optimize the catalytic performances of the system. For this reason, samples containing increasing amount of vanadium were prepared and tested in the oxidation of o-xylene, with the aim of find a correlations between V/Ti/O catalytic activity and the amount of the different vanadium species. The second part deals with the role of a gas-phase promoter. Catalytic surface can change under working conditions; the high temperatures and a different gas-phase composition could have an effect also on the formation of different V species. Furthermore, in the industrial practice, the vanadium oxide-based catalysts need the addition of gas-phase promoters in the feed stream, that although do not have a direct role in the reaction stoichiometry, when present leads to considerable improvement of catalytic performance. Starting point of my investigation is the possibility that steam, a component always present in oxidation reactions environment, could cause changes in the nature of catalytic surface under reaction conditions. For this reason, the dynamic phenomena occurring at the surface of a 7wt% V2O5 on TiO2 catalyst in the presence of steam is investigated by means of Raman spectroscopy. Moreover a correlation between the amount of the different vanadium species and catalytic performances have been searched. Finally, the role of dopants has been studied. The industrial V/Ti/O system contains several dopants; the nature and the relative amount of promoters may vary depending on catalyst supplier and on the technology employed for the process, either a single-bed or a multi-layer catalytic fixed-bed. Promoters have a quite remarkable effect on both activity and selectivity to phthalic anhydride. Their role is crucial, and the proper control of the relative amount of each component is fundamental for the process performance. Furthermore, it can not be excluded that the same promoter may play different role depending on reaction conditions (T, composition of gas phase..). The reaction network of phthalic anhydride formation is very complex and includes several parallel and consecutive reactions; for this reason a proper understanding of the role of each dopant cannot be separated from the analysis of the reaction scheme. One of the most important promoters at industrial level, which is always present in the catalytic formulations is Cs. It is known that Cs plays an important role on selectivity to phthalic anhydride, but the reasons of this phenomenon are not really clear. Therefore the effect of Cs on the reaction scheme has been investigated at two different temperature with the aim of evidencing in which step of the reaction network this promoter plays its role.

Studio microstrutturale e tribologico di componenti per motori idraulici a pistoni radiali a colonna di fluido

Lo studio condotto ha lo scopo di aumentare la vita in esercizio di motori idraulici a pistoni radiali a colonna di fluido, studiandone e migliorandone il comportamento tribologico. Questa tipologia di motori è adatta per generare alte coppie a basse velocità e si impiega in sistemi di movimentazione lenta per carichi pesanti. Il contatto in condizioni di strisciamento fra cilindri telescopici ed albero eccentrico rotante, può portare all’usura dei componenti coinvolti e quindi al trafilamento dell’olio che circola nel motore, causando cali di efficienza. Lo studio ha previsto un’indagine del tipo Failure Analysis su componenti del motore sottoposti a prove a banco. Successivamente, è stato condotto uno studio tribologico, al fine di valutare il comportamento del sistema e definire possibili modifiche ai componenti per il miglioramento del motore. Dalla Failure Analysis, è emerso che il meccanismo di usura prevalente risulta essere l’abrasione a due corpi. Le prove tribologiche di laboratorio, condotte in condizioni che hanno permesso di riprodurre i meccanismi di usura dominanti nelle prove a banco, hanno dato luogo a transizioni sia nell’attrito che nell’usura, il cui verificarsi dipende da: carico applicato, distanza di strisciamento, durezza dei materiali a contatto.

Progetto, sviluppo e messa in opera di un server per cartografia digitale attiva

La tesi riguarda la creazione di una architettura che ha lo scopo di far interagire attivamente un utente con una mappa digitale tramite browser web e un applicativo che calcola dei percorsi in base ad un algoritmo di ottimizzazione. Un ambito interessante, attuale e che avrà, molto probabilmente, notevoli sviluppi futuri. Basti pensare per esempio a come le persone interagiscono con le mappe digitali tramite i famosi Google Maps o Google Earth, Bing Maps e OpenStreetMap. Questa interazione è diventata talmente naturale che è ormai intuitivo ruotare la rotellina del mouse per zoomare oppure tenere premuto il tasto sinistro per trascinare la mappa. Spesso questi applicativi web offrono servizi per il calcolo di percorsi, o rilasciano anche delle API per interagire e personalizzare alcuni aspetti, anche se spesso in modo limitato per questioni di copyright. In questo contesto entrano in gioco associazioni, singoli individui e fondazioni che creano software e standard fruibili da chiunque per creare applicativi e architetture personalizzate senza vincoli di diritti troppo limitanti. In questa tesi viene mostrato un approccio che permette una personalizzazione molto dettagliata e un'alta interoperabilità con queste applicazioni specifiche. Ma tutti questi aspetti positivi sono fruibili, per ora, solo mediante supporto umano avente un bagaglio di esperienze tecniche adeguate.