5,079 research outputs found

    Wavelength tunable 10-GHz 3-ps pulse source using a dispersion decreasing fiber-based nonlinear optical loop mirror

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    We experimentally demonstrate the use of a dispersion decreasing fiber (DDF)-based nonlinear optical loop mirror (NOLM) for the generation of wavelength tunable soliton-like pulses at a repetition rate of 10 GHz. We compress ~12 ps Gaussian pulses from an electro-absorption modulator (EAM) (followed by 125 m of DCF for preliminary linear dispersion compensation) into 3 ps pedestal-free pulses using both high-order soliton compression and nonlinear switching effects within an 8.5 km DDF-based loop mirror. The output pulses from the DDF-based NOLM show considerable pedestal reduction compared to those obtained by directly compressing the EAM seed pulses via a single passage through the DDF. Wavelength tuning of the compressed pulses over a ~15 nm bandwidth (from 1541 to 1556 nm) is demonstrated without a significant increase in pulse duration or degradation in pulse quality

    Player agency in interactive narrative: audience, actor & author

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    The question motivating this review paper is, how can computer-based interactive narrative be used as a constructivist learn- ing activity? The paper proposes that player agency can be used to link interactive narrative to learner agency in constructivist theory, and to classify approaches to interactive narrative. The traditional question driving research in interactive narrative is, ‘how can an in- teractive narrative deal with a high degree of player agency, while maintaining a coherent and well-formed narrative?’ This question derives from an Aristotelian approach to interactive narrative that, as the question shows, is inherently antagonistic to player agency. Within this approach, player agency must be restricted and manip- ulated to maintain the narrative. Two alternative approaches based on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are reviewed. If a Boalian approach to interactive narrative is taken the conflict between narrative and player agency dissolves. The question that emerges from this approach is quite different from the traditional question above, and presents a more useful approach to applying in- teractive narrative as a constructivist learning activity

    Phase morphology and rheological behavior of polymer/layered silicate nanocomposites

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    Rheological behavior of polymer/layered silicate nanocomposites an strongly dependent not only upon their microstructure but also upon the interfacial characteristics. Different phase morphology (intercalated or exfoliated) of polymer/clay is obtained according to interfacial characteristics between polymer chains and clay. In intercalated structure, the presence of randomly oriented anisotropic stacks of silicate layers is responsible for the enhancement of both moduli. The PS/clay nanocomposites exhibit a slight enhancement at low frequency because of its simple intercalated structure and little interaction. On the other hand, the PS-co-ma/clay nanocomposites have a similar intercalated structure but exhibit a distinct plateau-like behavior at low frequency since the PS-co-ma has a strong attractive interaction with the silicate layers. Finally, PE-g-ma/clay nanocomposites display an exfoliated structure, which exhibit both a distinct plateau-like behavior at low frequency and enhanced moduli at high frequency. Percolation structure as well as large interfacial area between polymer chains and clay are responsible for the theological behavior

    Crying

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    Crying explores the tension between an 'authentic' and a 'performed' moment of vulnerability and the complex emotions associated with being both artist and new mother. The artist has approximately one hour to capture this work in her backyard, before her baby wakes and demands her full attention and care. The challenge she sets herself is to cry on camera. In dialogue with Bas Jan Ader's I'm too sad to tell you (1970), in which Ader sobs for an unknown reason (in the tradition of the "melancholy white male artist", as Jennifer Doyle writes in her book  'Hold it Against Me: Difficulty and Emotion in Contemporary Art'), Crying captures a performed and staged sadness, a feminist reworking of Ader's intimate yet self-indulgent action. Ader has become a mythical figure after he was lost at sea in 1975, three weeks after setting off alone in a small sailing boat, attempting to cross the Atlantic Ocean. In motherhood, Lim feels almost daily to be 'lost at sea', charged with the responsibility of a new life and love so strong as to be almost unbearable

    Phase morphology and rheological behavior of polymer/layered silicate nanocomposites

    No full text
    Rheological behavior of polymer/layered silicate nanocomposites an strongly dependent not only upon their microstructure but also upon the interfacial characteristics. Different phase morphology (intercalated or exfoliated) of polymer/clay is obtained according to interfacial characteristics between polymer chains and clay. In intercalated structure, the presence of randomly oriented anisotropic stacks of silicate layers is responsible for the enhancement of both moduli. The PS/clay nanocomposites exhibit a slight enhancement at low frequency because of its simple intercalated structure and little interaction. On the other hand, the PS-co-ma/clay nanocomposites have a similar intercalated structure but exhibit a distinct plateau-like behavior at low frequency since the PS-co-ma has a strong attractive interaction with the silicate layers. Finally, PE-g-ma/clay nanocomposites display an exfoliated structure, which exhibit both a distinct plateau-like behavior at low frequency and enhanced moduli at high frequency. Percolation structure as well as large interfacial area between polymer chains and clay are responsible for the theological behavior

    Charisma and Spirituality in the Early Church: A Study of Messalianism and Pseudo-Macarius

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    The thesis is an investigation into the concept of Charisma and Spirituality in the Early Church with particular emphasis upon the writings of Ps-Macarius, and of a group of ascetics known as the Messalians, evident in the late fourth / early fifth centuries. The Macarian writings are examined to see what they reveal about the experiential pneumatic theology of the Early Church, the relationship between Syrian and Hellenic traditions of Christian Rhetoric, and the relationship between Ps-Macarius and the Cappadocian Circle. The Macarian corpus as a whole is examined to assess its rhetorical influences and style. The rhetoric of the Macarian corpus is seen to illustrate a high degree of sophistication. This study also gives definition to two terms that have become imprecise and diverse in their use: 'enkrateia' (self-control), and `Syrian Christianity'. By isolating the characteristics of enkratefa the definitive stages of an encratic lifestyle are identified. The breaking down of the term into enkrateia, radical enkrateta and exclusive enkrateta enables a much clearer discussion to take place as to the nature of the encratic theology of a group or individual. The final element of this study is a consideration of the distinct Macarian imagery that is evident within the corpus. Two images are considered in detail, the 'flight of the soul' and 'sober intoxication'. Overall this study shows the variety of influences upon Ps-Macarius, and the uniqueness of his expression. The influences upon Ps-Macarius include a context of endemic Syrian spirituality, a radical encratic lifestyle, a Hellenic rhetorical training, and a distinct interpretation of Platonic and Neo- Platonic images, coupled to the wider Judaic / Mesopotamian influences of his Church. It is shown that Ps-Macarius represents an individual voice that is distinct and recognisable amongst the Fathers of the Church

    Nuclear translocation and signalling of L1-CAM in human carcinoma cells requires ADAM10 and presenilin/gamma-secretase activity

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    L1-CAM (L1 cell-adhesion molecule), or more simply L1, plays an important role in the progression of human carcinoma. Overexpression promotes tumour-cell invasion and motility, growth in nude mice and tumour metastasis. It is feasible that L1-dependent signalling contributes to these effects. However, little is known about its mechanism in tumour cells. We reported previously that L1 is cleaved by ADAM (a disintegrin and metalloprotease) and that the cytoplasmic part is essential for L1 function. Here we analysed more closely the role of proteolytic cleavage in L1-mediated nuclear signalling. Using OVMz carcinoma cells and L1-transfected cells as a model, we found that ADAM10-mediated cleavage of L1 proceeds in lipid raft and non-raft domains. The cleavage product, L1-32, is further processed by PS (presenilin)/gamma-secretase to release L1-ICD, an L1 intracellular domain of 28 kDa. Overexpression of dominantnegative PS1 or use of a specific gamma-secretase inhibitor leads to an accumulation of L1-32. Fluorescence and biochemical analysis revealed a nuclear localization for L1-ICD. Moreover, inhibition of ADAM10 and/or gamma-secretase blocks nuclear translocation of L1-ICD and L1-dependent gene regulation. Overexpression of recombinant L1-ICD mediates gene regulation in a similar manner to full-length L1. Our results establish for the first time that regulated proteolytic processing by ADAM10 and PS/gamma-secretase is essential for the nuclear signalling of L1 in human carcinoma cell lines. Key words: a disintegrin and metalloprotease 10 (ADAM10), L1 cell-adhesion molecule (L1-CAM), nuclear translocation, presenilin (PS)/gamma-secretase activity, raft, signalling

    Degradation of sulfanomides in water using direct UV photolysis and UV/PS processes

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    The presence of residual antibiotics in water has sparked an increased social concern, where it is classified as a rapidly growing class of contaminants. The adverse effects have been associated with its rising incidence of antibiotic-resistant genes and bacteria. In particular sulfonamides (SAs) have been a commonly used antibiotic for treating human diseases and as veterinary medicine. Fifteen SAs were chosen as target pollutants in this project. Their photodegradation rates were investigated using a low-pressure UV-254 Hg lamp by direct UV photolysis and UV/persulfate (UV/PS) processes. Removal of SAs under direct UV photolysis processes is inefficient due to their low quantum yield, while the photodegradation of SAs significantly increases with the addition of persulfate in the UV/PS system due to the generation of sulfate radicals. A ratio of 20:1 [oxidant/pollutant] was applied in this study. As compared to the maximum removal of 50% by direct UV photolysis for up to an hour, UV/PS system demonstrates a maximum removal efficiency of 98% for merely 7 minutes. A comparison was made between UV/PS and UV/H2O2 processes with the same oxidant to pollutant ratio. The determined second-order rate constants of radicals with SAs show that UV/PS is more efficient than UV/H2O2 in degrading SAs. Quantitative structure activity relationship (QSAR) model was then developed using twelve quantum-chemical descriptors to correlate the photodegradation rate and the structural characteristics of SAs. Due to the larger independent variables of Fukui indices and qH+, they are considered as the key parameters in the optimal model for direct UV photolysis. QSAR model was also developed with the first-order rate constant by UV/PS process. Fukui indices, Ehomo and Elumo are considered as the key parameters in the regression model due to a higher independent variable.Bachelor of Engineering (Environmental Engineering
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