6,058 research outputs found
Wavelength tunable 10-GHz 3-ps pulse source using a dispersion decreasing fiber-based nonlinear optical loop mirror
No full textWe 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
No full textThe 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
"Talk-stories" in the fictions of Maxine Hong Kingston and Amy Tan
No full textThis thesis investigates the "talk-story" narrative patterns, which stem from the Chinese oral tradition, in selected works of two contemporary Chinese American women writers, Maxine Hong Kingston and Amy Tan. In The Woman Warrior, Kingston has experimented with a new kind of "talk-story" writing in blending family stories, cultural myths, fantasy, autobiographical details, and history, as she attempts to model her work on the familial talk-story culture she was nurtured in. Borrowing the term "talk story" from a pidgin Hawai'ian expression, Kingston develops a special kind of generic "talk-story" as an artistic creation in her fictions. Amy Tan's The Joy Luck Club is often compared to The Woman Warrior and a number of critics have observed the use of "talk-story" in Tan's novels, but the talk-story components in the two writers' works have been largely discussed in relation to the mother-daughter dyads and few critics have distinguished the different usages and functions of "talk-stories" in their works. Through a literary analysis of their works, my thesis attempts to enrich the concept of "talk-story" originated from Kingston, and discusses its relation to the works of Kingston and Tan, with an aim to teasing out the two writers' differences within their sameness. While Kingston exhibits a talk-story narrative structure in her works, Tan mainly confines the talk-story elements at a textual level as a healing narrative therapy between generations. I will argue that while both writers exemplify talk-story as a form of self-expression and empowerment, their talk-stories function differently as they interact with the mainstream discourse: while Kingston remodels the Chinese talk-story pattern by making it a form of literary art, Tan refashions talk-story as a kind of "talking-cure, " as in western psychotherapy, in her fictions and writes in the popular arena
Simple models and concepts as tools for the study of sustained soil productivity in long-term experiments. II. Crop nutrient equivalents, balanced supplies of available nutrients, and NPK triangles
No full textTwo NPK factorial trials, one in Vietnam and one in The Netherlands were (re-)analyzed to find causes of success or failure with regard to sustained soil productivity, using the concept of crop nutrient equivalents (CNE). A (k)CNE is the quantity of a nutrient that, under conditions of balanced nutrition, has the same effect on yield as 1 (k)g of nitrogen. The percentages the nutrients take in the (k)CNE sum of N, P and K are plotted along the sides of a triangle. Soil, crop and input NPK are indicated in the triangle. Balanced crop NPK is found in the centre of the triangle, and required NPK inputs are on a straight line in the extension of the line trough the point of soil NPK and the centre. Experimental inputs were compared with inputs required for balanced NPK. In Vietnam, responses to P and soil available N:P:K pointed to severe shortage of P. Rice yields increased over time in dry but not in wet seasons. The lower yields in wet seasons were ascribed to insufficiently long periods between the dry and the next wet seasons for replenishment of labile soil P. In the Netherlands, four crops were grown in rotation on a former sea bottom. Only N had a strong effect on yield. Soil available N:P:K revealed low N, very high K and medium P. Recovery of fertilizer N was high because of capillary rise of groundwater and absence of leaching. In both trials, first-season chemical crop analysis would directly have detected disproportions of soil available N, P and K. This knowledge could have improved the experimental designs, optimized nutrient use efficiency and minimized losses of N and K to the environmen
Deep proteogenomics; high throughput gene validation by multidimensional liquid chromatography and mass spectrometry of proteins from the fungal wheat pathogen Stagonospora nodorum
No full textBackground
Stagonospora nodorum, a fungal ascomycete in the class dothideomycetes, is a damaging pathogen of wheat. It is a model for necrotrophic fungi that cause necrotic symptoms via the interaction of multiple effector proteins with cultivar-specific receptors. A draft genome sequence and annotation was published in 2007. A second-pass gene prediction using a training set of 795 fully EST-supported genes predicted a total of 10762 version 2 nuclear-encoded genes, with an additional 5354 less reliable version 1 genes also retained.
Results
In this study, we subjected soluble mycelial proteins to proteolysis followed by 2D LC MALDI-MS/MS. Comparison of the detected peptides with the gene models validated 2134 genes. 62% of these genes (1324) were not supported by prior EST evidence. Of the 2134 validated genes, all but 188 were version 2 annotations. Statistical analysis of the validated gene models revealed a preponderance of cytoplasmic and nuclear localised proteins, and proteins with intracellular-associated GO terms. These statistical associations are consistent with the source of the peptides used in the study. Comparison with a 6-frame translation of the S. nodorum genome assembly confirmed 905 existing gene annotations (including 119 not previously confirmed) and provided evidence supporting 144 genes with coding exon frameshift modifications, 604 genes with extensions of coding exons into annotated introns or untranslated regions (UTRs), 3 new gene annotations which were supported by tblastn to NR, and 44 potential new genes residing within un-assembled regions of the genome.
Conclusion
We conclude that 2D LC MALDI-MS/MS is a powerful, rapid and economical tool to aid in the annotation of fungal genomic assemblies
Charisma and Spirituality in the Early Church: A Study of Messalianism and Pseudo-Macarius
No full textThe 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
No full textL1-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
Inverse machine learning for multi-criteria decision making
No full textMulti-criteria decision making involves solving a multi-objective optimization problem (MOP) and selecting an optimal trade-off solution from the Pareto set (PS) based on preferred criteria/ objectives. The decision maker (DM) can articulate her preferences before, during, or after solving the MOP. However, specifying preferences a priori without knowledge of the Pareto data can be challenging. As an alternative, the DM can interactively refine her preferences during optimization, but this process can be cognitively demanding, especially when the number of query increases. A third approach involves solving the MOP to acquire the Pareto data first, allowing the DM to select a solution a posteriori based on her preferences. However, discovering solutions that lie on the PS manifold and satisfying the DM's preferences is often unlikely, particularly in domains where evaluation data is costly.
To overcome the limited decision choices in the acquired PS, an inverse machine learning model can be invoked to map arbitrary preferences in the objective space to new solutions in the PS. The accuracy of this inverse model, however, is constrained by the inherently small training data available in expensive optimization domains. To alleviate this small data challenge, this thesis introduces a pioneering study on multi-source inverse transfer learning. The proposed method leverages experiential source tasks to enhance PS learning in the target MOP task, uniquely facilitating information transfer between heterogeneous source-target pairs through common objective spaces.
Additionally, to mitigate the curse of dimensionality in the decision space, the concept of PS representation learning is introduced. This approach reduces the problem to its smallest possible dimensions while accurately capturing the Pareto optima. A denoising autoencoder is utilized to discover a compressed latent representation of a sparsely populated PS, leveraging its bottleneck architecture. This representation then serves to create compact inverse models, mapping DM's preferences in the objective space to the dimensionally reduced PS.
The final part of the thesis explores scenarios where source task is absent for inverse transfer learning. It presents the novel idea of Monte Carlo walk-pull as a means of PS augmentation. Techniques are proposed for the first time to couple the walk-pull process with an inverse machine learner, enabling accurate modeling of the optima in problems with highly non-linear PS shapes.
All three proposed approaches have been empirically tested on benchmarks MOPs and real-world MOPs based on an industrial supply chain planning problem and a high-fidelity multidisciplinary simulation data of composite materials manufacturing processes. The results are promising, showcasing significant improvements in the predictive accuracy and Pareto approximation capacity of PS learning. With such accurate inverse models, a future of on-demand Human-AI interaction facilitating multi-objective decisions can be envisioned.Doctor of Philosoph
LinoSPAD2: A 512×1 linear SPAD camera with system-level 135-ps SPTR and a reconfigurable computational engine for time-resolved single-photon imaging
No full textThe LinoSPAD2 camera combines a 512×1 linear single-photon avalanche diode (SPAD) array with an FPGA-based photon-counting and time-stamping platform, to create a reconfigurable sensing system capable of detecting single photons. The read-out is fully parallel, where each SPAD is connected to a different FPGA input. The hardware can be reconfigured to achieve different functionalities, such as photon counters, time-to-digital converter (TDC) arrays and histogramming units. Time stamping is performed by an array of 64 TDCs, with 20 ps resolution (LSB), serving 256 channels by means of 4:1 sharing. At sensor level, the pixel pitch is 26.2 μm with a fill factor of 25.1%. The median dark count rate of each SPAD at room temperature is below 100 cps at 6V excess bias, the single-photon timing resolution (SPTR) of each channel is 50 ps FWHM, and the peak photon detection probability reaches ~50% at 510 nm at the same excess bias. The fill factor can be increased by 2.3× by means of microlenses, with good spatial uniformity and flat spectral response above 400 nm. At system level, the average instrument response function (IRF) is 135 ps FWHM. The LinoSPAD2 camera enables a wide range of time-of-flight and time-resolved applications, including 3D imaging, fluorescence lifetime imaging microscopy (FLIM), heralded spectroscopy, and compressive Raman imaging, to name a few. Thanks to its features, LinoSPAD2 is a novel generation of reconfigurable single-photon image sensors capable of adapting their read-out and processing to match application-specific requirements, and combining SPAD arrays with advanced, massively-parallel computational functionalities. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.QCD/DiCarlo La
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