Some forms of exceptional Lie algebras

Some forms of Lie algebras of types E_6, E_7, and E_8 are constructed using the exterior cube of a rank 9 finitely generated projective module

Bonding graphite with fused silver chloride

Silver chloride use in technique for fusion bonding of graphite to silver, glass, ceramics, and certain other metal

Locally adaptive smoothing with Markov random fields and shrinkage priors

We present a locally adaptive nonparametric curve fitting method that operates within a fully Bayesian framework. This method uses shrinkage priors to induce sparsity in order-k differences in the latent trend function, providing a combination of local adaptation and global control. Using a scale mixture of normals representation of shrinkage priors, we make explicit connections between our method and kth order Gaussian Markov random field smoothing. We call the resulting processes shrinkage prior Markov random fields (SPMRFs). We use Hamiltonian Monte Carlo to approximate the posterior distribution of model parameters because this method provides superior performance in the presence of the high dimensionality and strong parameter correlations exhibited by our models. We compare the performance of three prior formulations using simulated data and find the horseshoe prior provides the best compromise between bias and precision. We apply SPMRF models to two benchmark data examples frequently used to test nonparametric methods. We find that this method is flexible enough to accommodate a variety of data generating models and offers the adaptive properties and computational tractability to make it a useful addition to the Bayesian nonparametric toolbox.Comment: 38 pages, to appear in Bayesian Analysi

Research note: Measuring cultural values - The case of residents' attitudes to the Saltaire Festival

This research note discusses the findings and methodological issues arising from a cultural values survey of residents, particularly in relation to civic pride. In addition to offering insights to the particular case - the Saltaire Festival in the north of England - it provides an approach that might be used elsewhere

Perceptual adaptation by normally hearing listeners to a simulated "hole" in hearing

Simulations of cochlear implants have demonstrated that the deleterious effects of a frequency misalignment between analysis bands and characteristic frequencies at basally shifted simulated electrode locations are significantly reduced with training. However, a distortion of frequency-to-place mapping may also arise due to a region of dysfunctional neurons that creates a "hole" in the tonotopic representation. This study simulated a 10 mm hole in the mid-frequency region. Noise-band processors were created with six output bands (three apical and three basal to the hole). The spectral information that would have been represented in the hole was either dropped or reassigned to bands on either side. Such reassignment preserves information but warps the place code, which may in itself impair performance. Normally hearing subjects received three hours of training in two reassignment conditions. Speech recognition improved considerably with training. Scores were much lower in a baseline (untrained) condition where information from the hole region was dropped. A second group of subjects trained in this dropped condition did show some improvement; however, scores after training were significantly lower than in the reassignment conditions. These results are consistent with the view that speech processors should present the most informative frequency range irrespective of frequency misalignment. 0 2006 Acoustical Society of America

Contributions of temporal encodings of voicing, voicelessness, fundamental frequency, and amplitude variation to audiovisual and auditory speech perception

Auditory and audio-visual speech perception was investigated using auditory signals of invariant spectral envelope that temporally encoded the presence of voiced and voiceless excitation, variations in amplitude envelope and F-0. In experiment 1, the contribution of the timing of voicing was compared in consonant identification to the additional effects of variations in F-0 and the amplitude of voiced speech. In audio-visual conditions only, amplitude variation slightly increased accuracy globally and for manner features. F-0 variation slightly increased overall accuracy and manner perception in auditory and audio-visual conditions. Experiment 2 examined consonant information derived from the presence and amplitude variation of voiceless speech in addition to that from voicing, F-0, and voiced speech amplitude. Binary indication of voiceless excitation improved accuracy overall and for voicing and manner. The amplitude variation of voiceless speech produced only a small increment in place of articulation scores. A final experiment examined audio-visual sentence perception using encodings of voiceless excitation and amplitude variation added to a signal representing voicing and F-0. There was a contribution of amplitude variation to sentence perception, but not of voiceless excitation. The timing of voiced and voiceless excitation appears to be the major temporal cues to consonant identity. (C) 1999 Acoustical Society of America. [S0001-4966(99)01410-1]

Selling themselves short: How inclusive is the UCAS application process to non-traditional students?

Discussions around inclusive admissions traditionally concern widening access and enabling students from underrepresented groups to enter university. However, the actual process of applying via UCAS is rarely considered. In this study, we address the question, ‘how inclusive is a UCAS personal statement?’ We consider the challenges of applying to university and writing a personal statement from the perspective of mature, former foundation students. By drawing on existing literature, personal statements and student experiences, we highlight the lack of inclusivity. The primary thesis is that the current incarnation of the personal statement needs adjustment as it is not equitable and can marginalise applicants. The study makes suggestions for improving the system and increased information, advice and guidance for applicants

Could posterior-anterior projection cervical spine radiographs improve image quality and dose reduction

Introduction: Anterior-posterior (AP) cervical spine X-rays are routine examinations to assess degenerative change, persistent pain and traumatic injuries. Multiple radiosensitive organs lie anteriorly within this anatomical region, increasing the stochastic risk of cancer. If a posterior-anterior (PA) projection was utilised, the radiation dose could potentially be reduced. The hypothesis of this study is to evaluate the change in radiation dose and image quality between AP and PA positions. Materials and Methods: An anthropomorphic phantom was positioned AP erect against a digital radiography (DR) detector with 30 thermoluminescent dosimeters (TLDs) inserted to record the thyroid, breast, ovaries, and testes absorbed radiation dose at an exposure of 66 kV and 8 mAs. The phantom was repositioned PA erect and repeated. Images were assessed against an image quality criteria Likert scale by qualified radiographers. The mean and standard deviations were calculated for dose and image quality and compared using a t-test and Wilcoxon Signed Ranks Test. Results: The PA erect cervical spine reduced radiation dose to the right thyroid by 92% (44.7 µGy; p=0.00) and the left thyroid by 89% (43.7 µGy; p=0.00), with further reductions in scatter dose to the breasts (0.35-0.45 µGy; p=0.85), ovaries (0.41 µGy; p=0.57), and testes (0.04 µGy; p=0.98). Image quality scores for the end plates, pedicles, joint spaces, spinous and transverse processes, cortical and trabecular bone patterns, and soft tissues were near equivalent (p=0.32). Conclusion: Data analysis suggests that PA cervical spine positioning for X-rays in the laboratory adheres to as low as reasonably practicable (ALARP) guidance on X-ray examinations to reduce radiation dose to male and female internal organs (thyroid, breast, ovaries) without a reduction in image quality compared to AP positioning. Further research in clinical practice is advised

Earthquake Early Warning and Beyond: Systems Challenges in Smartphone-based Seismic Network

Earthquake Early Warning (EEW) systems can effectively reduce fatalities, injuries, and damages caused by earthquakes. Current EEW systems are mostly based on traditional seismic and geodetic networks, and exist only in a few countries due to the high cost of installing and maintaining such systems. The MyShake system takes a different approach and turns people's smartphones into portable seismic sensors to detect earthquake-like motions. However, to issue EEW messages with high accuracy and low latency in the real world, we need to address a number of challenges related to mobile computing. In this paper, we first summarize our experience building and deploying the MyShake system, then focus on two key challenges for smartphone-based EEW (sensing heterogeneity and user/system dynamics) and some preliminary exploration. We also discuss other challenges and new research directions associated with smartphone-based seismic network.Comment: 6 pages, conference paper, already accepted at hotmobile 201