Naresuan University Journal
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A framework for plasticity implementation on the SpiNNaker neural architecture
No full textMany of the precise biological mechanisms of synaptic plasticity remain elusive, but simulations of neural networks have greatly enhanced our understandin g of how specific global functions arise from the massively parallel computation o f neurons and local Hebbian or spike-timing dependent plasticity rules. For simula ting large portions of neural tissue, this has created an increasingly strong need for large scale simulations of plastic neural networks on special purpose hardwar e platforms, because synaptic transmissions and updates are badly matched to compu ting style supported by current architectures. Because of the great diversity of b iological plasticity phenomena and the corresponding diversity of models, there is a great need for testing various hypotheses about plasticity before committing to one hardware implementation. Here we present a novel framework for investigating different plasticity approaches on the SpiNNaker distributed digital neural simula tion platform. The key innovation of the proposed architecture is to exploit the r econfigurability of the ARM processors inside SpiNNaker, dedicating a subset of th em exclusively to process synaptic plasticity updates, while the rest perform the usual neural and synaptic simulations. We demonstrate the flexibility of the propo sed approach by showing the implementation of a variety of spike- and rate-based l earning rules, including standard Spike-Timing dependent plasticity (STDP), voltag e-dependent STDP, and the rate-based BCM rule. We analyze their performance and va lidate them by running classical learning experiments in real time on a 4-chip Spi NNaker board. The result is an efficient, modular, flexible and scalable framework , which provides a valuable tool for the fast and easy exploration of learning mod els of very different kinds on the parallel and reconfigurable SpiNNaker system
Reconciling Ethnic Nationalism and Imperial Cosmopolitanism: The Lifeworlds of Tsyben Zhamtsarano (1880-1942)
No full textSelf-Association of Organic Solutes in Solution: A NEXAFS Study of Aqueous Imidazole
No full textN K-edge near-edge X-ray absorption fine-structure (NEXAFS) spectra of imidazole in concentrated aqueous solutions have been acquired. The NEXAFS spectra of the solution species differ significantly from those of imidazole monomers in the gas phase and in the solid state of imidazole, demonstrating the strong sensitivity of NEXAFS to the local chemical and structural environment. In the concentration range from 0.5 to 8.2 mol L-1 the NEXAFS spectrum of aqueous imidazole does not change strongly, confirming previous suggestions that imidazole self-associates are already present at concentrations more dilute than the range investigated here. We show that various types of electronic structure calculations (Gaussian, StoBe, CASTEP) provide a consistent and complete interpretation of all features in the gas phase and solid state spectra based on ground state electronic structure. This suggests that such computational modelling of experimental NEXAFS will permit an incisive analysis of molecular interactions by organic solutes in solutions. It is confirmed that microhydrated clusters with a single imidazole molecule are poor models of imidazole in aqueous solution. Our analysis indicates that models including both a hydrogen-bonded network of hydrate molecules as well as imidazole-imidazole interactions are necessary to explain the electronic structure evident in the NEXAFS spectra
Measures to assess well-being in low-carbon-dioxide cities
No full textPolicies aimed at reducing carbon dioxide emissions often focus on the need to change existing behaviours and social practices as well as to provide technological advances in energy supply, waste, transport, industry and infrastructure. While fundamentally important to the mitigation of climate change, little is written about the impact that achieving carbon dioxide reduction targets, particularly for the built environment, will have on individual and societal well-being and quality of life. This paper investigates how a set of measures can be developed to assess well-being in cities, both as they are at present and as they transition to ‘low-carbon-dioxide’ futures. It outlines the important relationship between well-being, low-carbon-dioxide development and the built environment. A strategy for obtaining and assessing well-being measures is explained, the measures are discussed and 100 selected measures are detailed. The paper ends by illustrating how these measures can be integrated into a wider study of well-being
Structural Features of Micelles of Zwitterionic Dodecyl-phosphocholine (C₁₂PC) Surfactants Studied by Small-Angle Neutron Scattering
No full textSmall-angle neutron scattering (SANS) was used to investigate the size and shape of zwitterionic dodecyl phosphocholine (C12PC) micelles formed at various concentrations above its critical micelle concentration (CMC = 0.91 mM). The predominant spherical shape of micelles is revealed by SANS while the average micellar size was found to be broadly consistent with the hydrodynamic diameters determined by dynamic light scattering (DLS). Cryogenic tunneling electron microscopy (cryo-TEM) shows a uniform distribution of structures, proposing micelle monodispersity ( Supporting Information ). H/D substitution was utilized to selectively label the chain, head, or entire surfactant so that structural distributions within the micellar assembly could be investigated using fully protonated, head-deuterated, and tail-deuterated PC surfactants in D2O and fully deuterated surfactants in H2O. Using the analysis software we have developed, the four C12PC contrasts at a given concentration were simultaneously analyzed using various core-shell models consisting of a hydrophobic core and a shell representing hydrated polar headgroups. Results show that at 10 mM, C12PC micelles can be well represented by a spherical core-shell model with a core radius and shell thicknesses of 16.9 ± 0.5 and 10.2 ± 2.0 Å (total radius 27.1 ± 2.0 Å), respectively, with a surfactant aggregation number of 57 ± 5. As the concentration was increased, the SANS data revealed an increase in core-shell mixing, characterized by the emergence of an intermediate mixing region at the spherical core-shell interface. C12PC micelles at 100 mM were found to have a core radius and shell thicknesses of 19.6 ± 0.5 and 7.8 ± 2.0 Å, with an intermediate mixing region of 3.0 ± 0.5 Å. Further reduction in the shell thickness with concentration was also observed, coupled with an increased mixing of the core and shell regions and a reduction in miceller hydration, suggesting that concentration has a significant influence on surfactant packing and aggregation within micelles.</p
The state of feminist and queer psychology:contemporary tensions, challenges and opportunities
No full textHPV testing alone is not as safe as cytology and selective HPV testing AGAINST: There is powerful evidence for primary cervical screening.
No full textDisabling Xauthors, disordering textsX: deconstructing disability and identity in changingX times
No full textDrawing on Badiou's writing we develop new insights on some central notions of the discourse on 'disability'. We offer eight agonistic, intersecting trajectories addressing these concepts. Drawing on authorial voices we criticise the grammatical and rhetorical manoeuvres we have previously undertaken as we represent ourselves aiming for forms of participatory engagement, thus offering both critique and self-critique. Previous poststructuralist accounts in this area have drawn on 'philosophers of difference', but mainly Deleuze and Guattari. This piece offers innovation in harnessing aspects of Badiou's thinking to issues surrounding 'discourses of disability' and notions of the research 'self' in its various 'impersonations'
“Redressing the Sleeper Effect: Evidence for the Favorable Persuasive Impact of Discounting Information Over Time in a Contemporary Advertising Context,”
No full textThe shift in the accessibility of positive and negative information about consumer products on the Internet calls for a revisiting of persuasion effects. A counterintuitive effect, called the sleeper effect, predicts that attitudes toward a persuasive message have the potential to increase in favorableness despite the presence of information discounting the message. An experimental study was conducted to support the existence of the sleeper effect, demonstrate its renewed relevance in the contemporary advertising environment, and provide a foundation for further sleeper effect studies Journal of Advertising Impact Factor & Description - ResearchGate. Available from: https://www.researchgate.net/journal/0091-3367_Journal_of_Advertising [accessed Dec 13, 2015]