7,630 research outputs found
Non-PORC behaviour of a class of descendant -groups
We prove that the number of immediate descendants of order of is
not PORC (Polynomial On Residue Classes) where is the -group of order
defined by du Sautoy's nilpotent group encoding the elliptic curve
. This has important implications for Higman's PORC conjecture
Dual-side and three-dimensional microelectrode arrays fabricated from ultra-thin silicon substrates
A method for fabricating planar implantable microelectrode arrays was demonstrated using a process that relied on ultra-thin silicon substrates, which ranged in thickness from 25 to 50 µm. The challenge of handling these fragile materials was met via a temporary substrate support mechanism. In order to compensate for putative electrical shielding of extracellular neuronal fields, separately addressable electrode arrays were defined on each side of the silicon device. Deep reactive ion etching was employed to create sharp implantable shafts with lengths of up to 5 mm. The devices were flip-chip bonded onto printed circuit boards (PCBs) by means of an anisotropic conductive adhesive film. This scalable assembly technique enabled three-dimensional (3D) integration through formation of stacks of multiple silicon and PCB layers. Simulations and measurements of microelectrode noise appear to suggest that low impedance surfaces, which could be formed by electrodeposition of gold or other materials, are required to ensure an optimal signal-to-noise ratio as well a low level of interchannel crosstalk
An investigation of data compression techniques for hyperspectral core imager data
We investigate algorithms for tractable analysis of real hyperspectral image data from core samples provided by AngloGold Ashanti. In particular, we investigate feature extraction, non-linear dimension reduction using diffusion maps and wavelet approximation methods on our data
SMILE: the creation of space for interaction through blended digital technology
Interactive Learning Environments at Sussex University is a course in which students are given mobile devices (XDAs) with PDA functionality and full Internet access for the duration of the term. They are challenged to design and evaluate learning experiences, both running and evaluating learning sessions that involve a blend of technologies. Data on technology usage was collected via backups, email and web-site logging as well as video and still photography of student-led sessions. Initial analysis indicates that large amounts of technical support, solid pedagogical underpinning and a flexible approach to both delivery context and medium are essential. The project operated under the acronym SMILE – Sussex Mobile Interactive Learning Environment
Nifurtimox Is Effective Against Neural Tumor Cells and Is Synergistic with Buthionine Sulfoximine.
Children with aggressive neural tumors have poor survival rates and novel therapies are needed. Previous studies have identified nifurtimox and buthionine sulfoximine (BSO) as effective agents in children with neuroblastoma and medulloblastoma. We hypothesized that nifurtimox would be effective against other neural tumor cells and would be synergistic with BSO. We determined neural tumor cell viability before and after treatment with nifurtimox using MTT assays. Assays for DNA ladder formation and poly-ADP ribose polymerase (PARP) cleavage were performed to measure the induction of apoptosis after nifurtimox treatment. Inhibition of intracellular signaling was measured by Western blot analysis of treated and untreated cells. Tumor cells were then treated with combinations of nifurtimox and BSO and evaluated for viability using MTT assays. All neural tumor cell lines were sensitive to nifurtimox, and IC50 values ranged from approximately 20 to 210 μM. Nifurtimox treatment inhibited ERK phosphorylation and induced apoptosis in tumor cells. Furthermore, the combination of nifurtimox and BSO demonstrated significant synergistic efficacy in all tested cell lines. Additional preclinical and clinical studies of the combination of nifurtimox and BSO in patients with neural tumors are warranted
Whether it's M-learing or E-learning, it must be ME learning: a case study of mobile learning in Higher Education
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An inconsistency in our labs
There is a gaping disparity between the way we practise medical research and the way we practise medicine; it is a significant void and one that shows no signs of shrinking. While the UK and the NHS go about treating patients in a deontological fashion, based on the principles of an age-old oath of doing no harm, we are utilising cold utilitarianism in research on animals
Identifying The Factors That Influence Retail Customer Loyalty And Capitalising Them
Much has been said about loyalty and the advantages that a loyal customer base offers to an organisation and more specifically to retail customers. With more than 2 billion loyalty programme memberships including hotel, supermarket, airline and financial services in the United States alone it is clear that loyalty programmes are an essential part of the marketing plan and strategy of retail organisations – a road to survival, growth and profits. This study focussed on one particular clothing retailer in Gauteng that on its own represents 20.3% of the market making it the largest clothing retailer in South Africa. Gauteng was selected due to its stature as the largest clothing retailer in South Africa and also the nature of its customer base which consists of three distinct groups of customers: (1) cash only non-loyalty programme members, (2) cash only loyalty programme members, and (3) credit customers who purchase on terms. This study investigated the factors that influence customer loyalty amongst members of a retail loyalty programme in the apparel retail industry and found that the two most important drivers of customer loyalty were merchandise availability and customer service related variables. Price did not feature as an important driver of loyalty opening opportunities for retailers to focus on loyalty marketing strategies that do not revolve solely around price but rather focus on long-term relationship building. The responses received from this research were illuminating and will be of value to retailers who have an existing loyalty programme or are contemplating the starting of a programme
Quantitative Ultrasound and B-mode Image Texture Features Correlate with Collagen and Myelin Content in Human Ulnar Nerve Fascicles
We investigate the usefulness of quantitative ultrasound (QUS) and B-mode
texture features for characterization of ulnar nerve fascicles. Ultrasound data
were acquired from cadaveric specimens using a nominal 30 MHz probe. Next, the
nerves were extracted to prepare histology sections. 85 fascicles were matched
between the B-mode images and the histology sections. For each fascicle image,
we selected an intra-fascicular region of interest. We used histology sections
to determine features related to the concentration of collagen and myelin, and
ultrasound data to calculate backscatter coefficient (-24.89 dB 8.31),
attenuation coefficient (0.92 db/cm-MHz 0.04), Nakagami parameter (1.01
0.18) and entropy (6.92 0.83), as well as B-mode texture features
obtained via the gray level co-occurrence matrix algorithm. Significant
Spearman's rank correlations between the combined collagen and myelin
concentrations were obtained for the backscatter coefficient (R=-0.68), entropy
(R=-0.51), and for several texture features. Our study demonstrates that QUS
may potentially provide information on structural components of nerve
fascicles
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