1,101 research outputs found
Aspectos Descritivos em Congruencia e Divergencias: Estudo Comparativo Mercosul UE
No full textQuesto capitolo introduce uno studio di caso sullo spazio di convergenze-divergenze Unione Europea-Mercosul, in materia di politiche per l'istruzione superiore nell'ambito. Vengono introdotti progetti di cooperazione internazionale UE-AL nei quali si procura promuovere ambiti di convergenza per la mobilità accademica e studentesca. Si riflette, infine sugli impatti che tale cooperazione può avere nei contesti locali di pratica
Power Supply Selective Mapping for Accurate Timing Analysis
No full textIn Deep Sub-Micron technologies post-layout timing analysis has become the most critical phase in the verification of large System-on-Chip (SoC) designs with several power-hungry blocks. The impact of coupling capacitances has been adequately analyzed, and modern signal integrity analysis tools can effectively consider the crosstalk-induced delay. However, an increasingly important factor that can introduce a severe performance loss is the power supply noise. As technology advances into the nanometer regime, the operating frequencies increase, and clock gating has emerged as an effective technique to limit the power consumption in block-based designs. As a consequence, the amplitude of the supply voltage fluctuations has reached values where techniques to include the effect of power supply noise into timing analysis based on linear models are no longer adequate, and the non-linear dependence of cell delay from supply voltage must be considered. In this work we present a practical methodology that accurately takes into account the power supply noise effects in static timing analysis, which can be seamlessly included into an industrial sign-off design flow. The experimental results obtained from the timing verification of an industrial SoC design have demonstrated the effectiveness of our approach
Formación en Red vs. Educación a distancia: nuevas fronteras de la práctica pedagógica. Del discurso docente único al modelo de la conversación formativa
No full textThis article attempts to highlight the problem of definition of concepts that can frame pedagogical practices linked to a new educational paradigm based on Social Web last developments.
Through a discussion group taken ahead between August 2009 and March 2010, the international eurolatinoamerican group REDES, compoused by researchers in educational technologies and distance education, have focused the problem of use of terms that identify pedagogical practices taken ahead within and through virtual spaces; further considering educational developments -read through several disciplines such anthropology, phylosophy, cultural and social psychology, sciences of communication). In this reflection, it has been considered how some pedagogical practices on the web are closer to traditional practices that recall traditional classroom settings where teachers' discourse and institutional perspective dominates all activity; whereas other practices can be certainly identified as spaces of participation and knowledge building, thorugh which a dialogic perspective is enacted and generates the expansion of participants' symbolic univers.
Nevertheless, it doesn't exist a terminology that is able of distinguish between the above mentioned diversity, being the adopted terms strongly linked with the means and technologies (virtual, electronic, online). Only in the last years it's possible to see the use of key terms associated with the issue of social interactions in a network. Considering this discusion about notions of education, instruction, formation, inside the french perspective (Lesne, 1977; Honoré, 1980, 1994; Barbier, 1980) and considering also the notion of dispositive (Roesler, 2008), this article aims to generate a critical perspective with regards to the denomination distance education -generally linked with a traditional pedagogical practice where knowledge access is dominated by teachers' discourse-; to adopt the concept of networked formation, that gives place to a model which proposal is to build dialogic spaces where learning occurs through conversation
Structure-function studies of the major insertion of the apicomplexan ferredoxin NADP+ reductase, investigated by mutagenesis and limited proteolysis
No full textApicomplexan parasites are a large phylum of unicellular and obligate intracellular organisms of great medical and economic importance. They include the human pathogens Plasmodium spp., the causative agents of malaria, and Toxoplasma gondii, an opportunistic human parasite. It was shown that most members of this phylum harbor a plastid-like organelle, called the apicoplast, of vegetal origin. The plant-type ferredoxin/ferredoxin-NADP+ reductase (Fd/FNR) redox system found in this organelle has been proposed as a target for novel drugs (1, 2). Elucidation of the properties and functions of this redox system would be greatly facilitated by a more detailed structural knowledge of the two components. Like many proteins from these protists, apicomplexan FNRs are characterized by the presence of unique peptide insertions of variable length and yet unknown function. The major insertion of T. gondii FNR (TgFNR) (28 aa with respect to maize root FNR) is near the FAD isoalloxazine ring binding motif. Thus, it is expected that it could influence the protein-protein interaction of the redox couple.
The aim of this study was therefore to investigate the structure and the involvement of this region of TgFNR in substrate binding by mutagenesis and limited proteolysis approaches.
All four proteinases tested yielded a limited number of peptides. Most of the cleavage sites were located within the major insertion of TgFNR, indicating that this region is surface exposed and is highly flexible. Furthermore, protection of the insertion by TgFd against proteolytic cleavage indicates a role for this region in ferredoxin binding (3).
Three different deleted forms of the parasite enzyme were produced, in which the insertion was fully removed (Del1), partially removed (Del2) or replaced with the homologous region of plant FNR (Del3). Compared to the wild type enzyme, Del2 and Del3 showed similar values for the kinetic parameters of the TgFd-dependent NADPH-cytochrome c reductase activity, while Km for ferredoxin of Del1 was highly increased. By affinity chromatography on immobilized TgFd, deleted TgFNRs were shown to bind more weakly TgFd than the wild-type enzyme. Del1 showed a remarkable loss of affinity for ferredoxin, probably because it lacks three positively charged residues which are present in Del2 and in Del3 mutants.
The results reported here allow us to conclude that the insertion of TgFNR is solvent exposed and structurally flexible. It is suggested to give rise to a 38-residue intrinsically unstructured subdomain, protruding from the top of the FAD-binding beta-barrel. Such a species-specific subdomain does not have major functions in protein folding and stability. Rather, it participates in TgFd binding, significantly increasing the stability of the protein-protein complex and improving the catalytic efficiency of the enzyme in the electron transfer to TgFd.
1. M. Vollmer et al. (2001) J. Biol. Chem. 276(8): 5483-5490
2. V. Pandini et al. (2002) J Biol Chem. 277(50):48463-48471.
3. V. Pandini et al. (2006) Biochemistry 45: 3563-357
Power Supply Selective Mapping for Accurate Timing Analysis
No full textIn Deep Sub-Micron technologies post-layout timing analysis has become the most critical phase in the verification of large System-on-Chip (SoC) designs with several power-hungry blocks. The impact of coupling capacitances has been adequately analyzed, and modern signal integrity analysis tools can effectively consider the crosstalk-induced delay. However, an increasingly important factor that can introduce a severe performance loss is the power supply noise. As technology advances into the nanometer regime, the operating frequencies increase, and clock gating has emerged as an effective technique to limit the power consumption in block-based designs. As a consequence, the amplitude of the supply voltage fluctuations has reached values where techniques to include the effect of power supply noise into timing analysis based on linear models are no longer adequate, and the non-linear dependence of cell delay from supply voltage must be considered. In this work we present a practical methodology that accurately takes into account the power supply noise effects in static timing analysis, which can be seamlessly included into an industrial sign-off design flow. The experimental results obtained from the timing verification of an industrial SoC design have demonstrated the effectiveness of our approach
NFYA alternative cleavage and polyadenylation in cancer
No full textThe majority of human genes can undergo alternative cleavage and polyadenylation resulting in the expression of distinct transcript isoforms and in a different microRNA-mediated regulation under certain conditions and states. In this context, we aim at studying the microRNA regulation of NFYA with a special focus on the 3’UTR repertoire. NFYA exists in two splicing isoforms and encodes for the regulatory subunit of the nuclear transcription factor Y, which is known to control key transcriptional changes in pathways broadly deregulated in cancer cells. The poor correlation between NF-YA protein and mRNA expression suggests that post-transcriptional regulation may be as relevant as other mechanisms to control NF-YA activity in different cancer types. In this regard, our preliminary bioinformatic analyses identified more than one potential alternative polyadenylation sites resulting in four possible 3’UTRs. Among these, only two exist in current annotations, though the 3’UTR that we found to be the mostly used in both normal and tumor tissues/cells is not yet annotated. Furthermore, such analyses did not highlight any association between a certain NFYA splicing isoform and a specific 3’UTR. Instead, we found an increased NF-YA protein/mRNA ratio when the usage of shortest 3’UTR is higher. In addition, different exon composition and/or different 3’UTR lengths may affect the structural conformation of the transcript, possibly resulting in changes in the accessibility of microRNA binding sites, thus ultimately altering post-transcriptional regulation. Bioinformatic and functional studies are ongoing to assess the differential usage of all potential alternative polyadenylation sites in different conditions/states. Moreover, the effect of different NFYA 3’UTRs on the transcript stability and protein level as well as the biological implications in the cancer context are under study by employing different strategies to alter the 3’UTR usage endogenously or exogenously. Therefore, our goal is to characterize the alternative cleavage and polyadenylation of NFYA in the cancer context from a functional and biological point of view
Proyecto Alfa-MIFORCAL: itinerarios para pensar la internacionalización de la formación de profesorado a través de la cooperación educativa
No full textQuesto articolo ha come scopo la presentazione della prima tappa di svolgimento del Programma di cooperazione educativa fra Europa e America Latina, “ALFA-MIFORCAL”, puntato alla formazione di qualità per l’insegnamento secondario. Partecipano a questo progetto 10 istituzioni dei seguenti paesi: Argentina, Brasile, Paraguay, Spagna, Portogallo e Italia (Capofila).
Il progetto ha avuto inizio nell’anno 2004 con la definizione di un piano formativo congiunto e unificato, alla quale ha fatto seguito una fase di studio dei processi di “Instructional Design” e del “Sistema di Valutazione”.
Operativamente, la prima tappa, svoltasi attraverso la collaborazione in rete ed incontri in presenza internazionali, ha visto il raggiungimento di obiettivi progettuali relativi a: a) la costruzione partecipata del curricolo di formazione degli insegnanti in una prospettiva internazionale, nell’armonizzazione e lo studio dei punti di convergenza e divergenza fra i sistemi educativi europei e latinoamericani; b) la selezione delle discipline e materie di insegnamento nonché degli adattamenti necessari per il rispetto della diversità culturale; c) la selezione dei docenti per la costituzione di un Collegio Docente Internazionale; d) la creazione di un gruppo di ricercatori orientato alla ricerca azione sulla didattica online e l’analisi comparata fra le diverse realtà coinvolte nel progetto MIFORCAL.
In questo articolo verranno presentati i risultati della prima tappa di lavoro sui processi appena accennati, per introdurre poi le ipotesi di base sugli elementi cardine del progetto formativo sperimentale nel suo momento di erogazione, ovvero: a) La creazione della struttura multipiattaforma rispondente tanto a criteri di qualità dell’e-learning quanto al rispetto delle differenze culturali delle realtà partecipanti; b) L’ uso eficiente delle ICT’s nella formazione dei docenti nell’ambito di diverse realtà socio-culturali e i protocolli di accessibilità alla rete;c) La costruzione di una struttura stabile per la formazione teorico-pratica di una rete di ricercatori e formatori interessati a definire come cambia il profilo professionale e culturale dell’insegnante nella società della conoscenza.
L’insieme degli elementi della prima tappa di lavoro hanno consentito di ipotizzare un modello di percorso formativo per promuovere la professionalità docente secondaria, e profili di competenze mirate alla mobilità internazionale dei docenti secondari
KERATOCYST : LITERATURE REVIEW,CASE REPORT AND DIFFERENTIAL DIAGNOSIS WITH GLOBULOMAXILLARY CYST
No full textAim: This was to underscore the primary importance of histological exams for an accurate differential diagnosis of cystic lesions, based not only on first and second level radiographs, considering the potential relapse of this lesion after its enucleation. Case report The patient complained of a swelling in the right maxillary vestibular region between teeth 11 and 13; the orthopantomograph showed an inverted-drop shaped radiolucent area suggesting a globulomaxillary cyst; the CT Dental Scan confirmed the presence of vestibular resorption. Surgical excision was performed: the lesion appeared rounded and of approximately 1 cm in diameter. The histological examination revealed a cystic lesion covered by keratinized squamous epithelium (parakeratosis)
Production and characterization of the Poisson's ratio of cellular structured metamaterials by additive manufacturing
No full textMetamaterials are materials designed to have peculiar, unconventional electromagnetic, acoustic, thermal, or mechanical properties. These properties do not derive from the chemical composition of the material but rather from its internal structure, characterized by a three-dimensional cellular architecture consisting of a periodic repetition of an elementary cell. Among the properties displayed by metamaterials, the negative Poisson's ratio, also known as auxetic behavior, is the most relevant for what concerns the mechanical behavior, and it results in an increase of the transversal dimension upon tensile elongation. Metamaterials find application in different fields such as biomedical, automotive, aerospace, and textile fields. A big push towards the study of these new materials has certainly been provided by the expansion of additive manufacturing, which allows to easily realize complex geometries without restrictions. The goal of this work is to compare the Poisson's ratio vs strain during tensile tests, carried out on various metamaterials, produced with different structures, with different materials, and by different additive technologies. In particular, chiral, honeycomb and reverse honeycomb geometries have been studied. The structures were produced in PLA and ABS by Material Extrusion and in resin by Stereolithography. The results show that, as expected, the chiral and the reverse honeycomb geometries have a negative Poisson's ratio while the honeycomb geometry has a positive one. Moreover, the samples produced by stereolithography result more ductile with higher deformation at failure. (C) 2022 The Authors. Published by Elsevier B.V
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