Optical gating of photoluminescence from color centers in hexagonal boron nitride.

This is the final version. Available from the publisher via the DOI in this record.We report on multicolor excitation experiments with color centers in hexagonal boron nitride at cryogenic temperatures. We demonstrate controllable optical switching between bright and dark states of color centers emitting around 2eV. Resonant, or quasi-resonant excitation of photoluminescence also pumps the color center, via a two-photon process, into a dark state, where it becomes trapped. Repumping back into the bright state has a step-like spectrum with a defect dependent threshold between 2.25 and 2.6eV. This behavior is consistent with photoionization and charging between optically bright and dark states of the defect. Furthermore, a second zero phonon line, detuned by +0.4eV, is observed in absorption with orthogonal polarization to the emission, evidencing an additional energy level in the color center.Engineering and Physical Sciences Research Council (EPSRC

Effects of consonantal constrictions on voice quality

A speech production experiment with electroglottography investigated how voicing is affected by consonants of differing degrees of constriction. Measures of glottal contact [closed quotient (CQ)] and strength of voicing [strength of excitation (SoE)] were used in conditional inference tree analyses. Broadly, the results show that as the degree of constriction increases, both CQ and SoE values decrease, indicating breathier and weaker voicing. Similar changes in voicing quality are observed throughout the course of the production of a given segment. Implications of these results for a greater understanding of source-tract interactions and for the phonological notion of sonority are discussed

The Accentual Phrase in Singapore English.

‘This is the peer-reviewed but unedited manuscript version of the following article: Chong, A. J. and J. Sneed German (2017). "The Accentual Phrase in Singapore English." Phonetica 74(2): 63-80.The final, published version is available at https://www.karger.com/?DOI=10.1159/000447429This paper reports on a speech production experiment that explores whether the accentual phrase (AP) represents an abstract level of prosodic phrasing in Singapore English. Specifically, it tests whether the right edge of the AP is associated with phrase-final lengthening, the degree of which can be distinguished from lengthening associated with the intonational phrase (IP). Target words were produced in matched sentence contexts in 3 phrasal positions: AP-medial (wordfinal), AP-final, and IP-final. As predicted, target words in AP-final position were longer than those in AP-medial position and shorter than those in IP-final position. Analysis of target duration and f0 together shows that AP boundaries are well discriminated from medial positions. Together, these results strongly support an AP level of phrasing for Singapore English and highlight its role in predicting timing variability

Health-state utilities in a prisoner population : a cross-sectional survey

Background: Health-state utilities for prisoners have not been described. Methods: We used data from a 1996 cross-sectional survey of Australian prisoners (n = 734). Respondent-level SF-36 data was transformed into utility scores by both the SF-6D and Nichol's method. Socio-demographic and clinical predictors of SF-6D utility were assessed in univariate analyses and a multivariate general linear model. Results: The overall mean SF-6D utility was 0.725 (SD 0.119). When subdivided by various medical conditions, prisoner SF-6D utilities ranged from 0.620 for angina to 0.764 for those with none/mild depressive symptoms. Utilities derived by the Nichol's method were higher than SF-6D scores, often by more than 0.1. In multivariate analysis, significant independent predictors of worse utility included female gender, increasing age, increasing number of comorbidities and more severe depressive symptoms. Conclusion: The utilities presented may prove useful for future economic and decision models evaluating prison-based health programs

EVH Black Holes, AdS3 Throats and EVH/CFT Proposal

Within class of generic black holes there are extremal black holes (with vanishing Hawking temperature T) and vanishing horizon area Ah, but with finite Ah/T ratio,the Extremal Vanishing Horizon (EVH) black holes. We study the near horizon limit of a four dimensional EVH black hole solution to a generic (gauged) Einstein-Maxwell dilaton theory and show that in the near horizon limit they develop a throat which is a pinching orbifold limit of AdS3. This is an extension of the well known result for extremal black holes the near horizon limit of which contains an AdS2 throat. We show that in the near EVH near horizon limit the pinching AdS3 factor turns to a pinching BTZ black hole and that this near horizon limit is indeed a decoupling limit. We argue that the pinching AdS3 or BTZ orbifold is resolved if the near horizon limit is accompanied by taking the 4d Newton constant G4 to zero such that the Bekenstein-Hawking entropy S = Ah/(4G4) remains finite. We propose that in this limit the near horizon EVH black hole is dual to a 2d CFT. We provide pieces of evidence in support of the EVH/CFT correspondence and comment on its connection to the Kerr/CFT proposal and speculations how the EVH/CFT may be used to study generic e.g. Schwarzchild-type black holes.Comment: 31 pages, 3 figures, JHEP styl

Magnetic resonance imaging protocols for paediatric neuroradiology

Increasingly, radiologists are encouraged to have protocols for all imaging studies and to include imaging guidelines in care pathways set up by the referring clinicians. This is particularly advantageous in MRI where magnet time is limited and a radiologist’s review of each patient’s images often results in additional sequences and longer scanning times without the advantage of improvement in diagnostic ability. The difficulties of imaging small children and the challenges presented to the radiologist as the brain develops are discussed. We present our protocols for imaging the brain and spine of children based on 20 years experience of paediatric neurological MRI. The protocols are adapted to suit children under the age of 2 years, small body parts and paediatric clinical scenarios

Human Computation and Convergence

Humans are the most effective integrators and producers of information, directly and through the use of information-processing inventions. As these inventions become increasingly sophisticated, the substantive role of humans in processing information will tend toward capabilities that derive from our most complex cognitive processes, e.g., abstraction, creativity, and applied world knowledge. Through the advancement of human computation - methods that leverage the respective strengths of humans and machines in distributed information-processing systems - formerly discrete processes will combine synergistically into increasingly integrated and complex information processing systems. These new, collective systems will exhibit an unprecedented degree of predictive accuracy in modeling physical and techno-social processes, and may ultimately coalesce into a single unified predictive organism, with the capacity to address societies most wicked problems and achieve planetary homeostasis.Comment: Pre-publication draft of chapter. 24 pages, 3 figures; added references to page 1 and 3, and corrected typ

Four patients with a history of acute exacerbations of COPD: implementing the CHEST/Canadian Thoracic Society guidelines for preventing exacerbations

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