784 resultados para Teacher and students interaction
Resumo:
Two complementary explanations have been offered by social psychologists to account for the universal hold of national identity, first that national identity is ideologically assumed, as it forms the ‘banal’ background of everyday life, and second that national identity is ‘hotly’ constructed and contested in political and everyday settings to great effect. However, ‘banal’ and ‘hot’ aspects of national identity have been found to be distributed unevenly across national and subnational groups and banality itself can be strategically used to distinguish between different groups. The present paper develops these ideas by examining possible reasons for these different modes and strategies of identity expression. Drawing upon intergroup theories of minority and majority relations, we examine how a group who see themselves unequivocally as a minority, Irish Travellers, talk about their national identity in comparison to an age and gender-matched sample of Irish students. We find that Travellers proactively display and claim ‘hot’ national identity in order to establish their Irishness. Irish students ‘do banality’, police the boundaries and reputation of Irishness, and actively reject and disparage proactive displays of Irishness. The implications for discursive understandings of identity, the study of intra-national group relations and policies of minority inclusion are discussed.
Resumo:
We report the direct imaging of surface plasmon propagation on thin silver films using the photon scanning tunneling microscope. It is found that the surface plasmon remains tightly confined in the original launch direction with insignificant scattering to other momentum states. A propagation length of 13.2 mum is measured at lambda = 632.8 nm. We also present images showing the interaction of a surface plasmon with the edge of the metal film supporting it. The most remarkable feature is the absence of a specularly reflected beam.
Resumo:
Analysis of molecular interaction and conformational dynamics of biomolecules is of paramount importance in understanding of their vital functions in complex biological systems, disease detection, and new drug development. Plasmonic biosensors based upon surface plasmon resonance and localized surface plasmon resonance have become the predominant workhorse for detecting accumulated biomass caused by molecular binding events. However, unlike surface-enhanced Raman spectroscopy (SERS), the plasmonic biosensors indeed are not suitable tools to interrogate vibrational signatures of conformational transitions required for biomolecules to interact. Here, we show that plasmonic metamaterials can offer two transducing channels for parallel acquisition of optical transmission and sensitive SERS spectra at the biointerface, simultaneously probing the conformational states and binding affinity of biomolecules, e.g. G-quadruplexes, in different environments (Fig. 1). We further demonstrate the use of the metamaterials for fingerprinting and detection of arginine-glycine-glycine domain of nucleolin, a cancer biomarker which specifically binds to a G-quadruplex, with the picomolar sensitivity. The dual-mode nanosensor will significantly contribute to unraveling the complexes of the conformational dynamics of biomolecules as well as to improving specificity of biodetection assays.
Resumo:
Analysis of binding recognition and conformation of biomolecules is of paramount important in understanding of their vital functions in complex biological systems. By enabling sub-wavelength light localization and strong local field enhancement, plasmonic biosensors have become dominant tools used for such analysis owing to their label-free and real-time attributes1,2. However, the plasmonic biosensors are not well-suited to provide information regarding conformation or chemical fingerprint of biomolecules. Here, we show that plasmonic metamaterials, consisting of periodic arrays of artificial split-ring resonators (SRRs)3, can enable capabilities of both sensing and fingerprinting of biomolecules. We demonstrate that by engineering geometry of individual SRRs, localized surface plasmon resonance (LSPR) frequency of the metamaterials could be tuned to visible-near infrared regimes (Vis-NIR) such that they possess high local field enhancement for surface-enhanced Raman scattering spectroscopy (SERS). This will provide the basis for the development of a dual mode label-free conformational-resolving and quantitative detection platform. We present here the ability of each sensing mode to independently detect binding adsorption and to identify different conformational states of Guanine (G)-rich DNA monolayers in different environment milieu. Also shown is the use of the nanosensor for fingerprinting and detection of Arginine-Glycine-Glycine (RGG) peptide binding to the G-quadruplex aptamer. The dual-mode nanosensor will significantly contribute to unraveling the complexes of the conformational dynamics of biomolecules as well as to improving specificity of biodetection assays that the conventional, population-averaged plasmonic biosensors cannot achieve.
Resumo:
Relatório da Prática de Ensino Supervisionada, Mestrado em Ensino (Economia e Gestão/Contabilidade), Universidade de Lisboa, Instituto de Educação, 2011
Resumo:
Trabalho de projeto de mestrado, Ciências da Educação (Formação de Adultos), Universidade de Lisboa, Instituto de Educação, 2013