The structure of some Atlantic islands as deduced from gravity and other geophysical data

Imperial Users onl

Pulse-train instabilities in a mode-locked argon laser: experimental studies

The output train of pulses from an acousto-optically mode-locked argon-ion laser was studied as a function of the loss modulation frequency for small detunings from the optimum c/2L modulation. A shift away from the optimum frequency by as little as 1 part in 10⁴ was found to produce several strong lower-frequency components that amplitude modulate the mode-locked pulse train. Notably, the strongest subharmonic is a frequency near ƒopt/4. Further detuning results in an irregular, slow (of the order of 10⁵ Hz) amplitude envelope on the pulse train. The homodyne spectrum of this phase of operation represents a progressive filling-in behavior reminiscent of deterministically chaotic systems

Pump pulse effects in synchronously pumped mode-locked dye lasers

We consider the role of the pump pulse in the output of a synchronously pumped mode-locked dye laser. Our theoretical formalism is a nonlinear dynamical model that includes semiclassical effects, dipole orientation, and intrband relaxation. In particular, we study the shortenting of the output pulse with decreasing pump pulse length and increasing pump level. Both of these predictions agree with experiments

Examining the validity and reliability of the Chinese version of the International Physical Activity Questionnaire, long form (IPAQ-LC)

Objective : To investigate the reliability and the validity of the long format, Chinese version of the International Physical Activity Questionnaire (IPAQ-LC). Design : Cross-sectional study, examining the reliability and validity of the IPAQ-LC compared with a physical activity log (PA-log) and objective accelerometry. Setting : Self-reported physical activity (PA) in Hong Kong adults. Subjects : A total of eighty-three Chinese adults (forty-seven males, thirty-six females) were asked to wear an ActiTrainer accelerometer (MTI-ActiGraph, Fort Walton Beach, FL, USA) for >10 h over 7 d, to complete a PA-log at the end of each day and to complete the IPAQ-LC on day 8. On a sub-sample of twenty-eight adults the IPAQ-LC was also administered on day 11 to assess its reliability. Results : The IPAQ-LC had good test–retest reliability for grouped activities, with intra-class correlation coefficients ranging from 0·74 to 0·97 for vigorous, moderate, walking and total PA, with between-test effect sizes that were small (<0·49). The Spearman correlation coefficients were statistically significant for vigorous PA (r = 0·28), moderate + walking PA (r = 0·27), as well as overall PA (r = 0·35), when compared with the accelerometry-based criterion measures, but none of the IPAQ activity categories correlated significantly with the PA-log. In absolute units, only the IPAQ light and overall PA did not differ significantly from the accelerometry measures, yet overall PA was able to faithfully discriminate between quartiles of PA (P = 0·019) when compared to accelerometry. Conclusions : The IPAQ-LC demonstrated adequate reliability and showed sufficient evidence of validity in assessing overall levels of habitual PA to be used on Hong Kong adults

3D terrain mapping and filtering from coarse resolution data cubes extracted from real-aperture 94 GHz radar

William D. Harcourt was funded by the Engineering and Physical Sciences Research Council (EPSRC; grant number: EP/R513337/1) and the Scottish Alliance for Geoscience, Environment and Society (SAGES). The data sets analysed in this paper were collected through a grant awarded by the National Centre for Earth Observation (NCEO) and in collaboration with the University of Glasgow (who collected short-range Terrestrial Laser Scanner (TLS) data), Lancaster University, and the CGG company. The authors are grateful to Eric Murphy, Breedon Aggregates Ltd. for arranging access to the quarryPeer reviewe

220GHz wideband 3D imaging radar for concealed object detection technology development and phenomenology studies

Part of the research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312745.We present a 220 GHz 3D imaging ‘Pathfinder’ radar developed within the EU FP7 project CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) which has been built to address two objectives: (i) to de-risk the radar hardware development and (ii) to enable the collection of phenomenology data with ~1 cm3 volumetric resolution. The radar combines a DDS-based chirp generator and self-mixing multiplier technology to achieve a 30 GHz bandwidth chirp with such high linearity that the raw point response is close to ideal and only requires minor nonlinearity compensation. The single transceiver is focused with a 30 cm lens mounted on a gimbal to acquire 3D volumetric images of static test targets & materials.Publisher PD

A 220 GHz 3D imaging radar with sub-cm3 voxel resolution for security applications

Radars operating at high millimetre and sub-millimetre wave frequencies are promising candidates for security applications such as people screening since they offer the possibility to form 3D images through clothing with sufficient resolution to detect concealed objects. High spatial resolution of order 1 cm can be achieved using practically sized antennas and high range resolution can be achieved using wideband FMCW chirps, e.g. 30 GHz, to yield 0.5 cm range bins. We present a 220 GHz test-bed ‘Pathfinder’ radar which achieves sub-cm3 voxel resolution with very high signal fidelity. The radar is used to de-risk technology under development for next generation people screening systems.Postprin

Gender issues in sport and exercise

Proceedings of the Gender Issues in Sport and Exercise Conference organised by the Centre for Physical Education and Sport, the Physical Education and Sports Science Unit of the University of Hong Kong, and sponsored by the Hong Kong Sports Development Board, Saturday, 25 November 1995, Sports House, Causeway Bay, Hong Kong.published_or_final_versionAppearance and performance: creating a gender based sport ethic in rhythmic gymnastics Johns, David P. Johns, David P. 90Portrayal of sportwoman in selected Hong Kong newspapers Hon, Sze-sze Hon, Sze-sze 89Introduction to the conference Speak, Mike Speak, Mike Macfarlane, Duncan Macfarlane, Duncan viiThe effectof gender-role stereotyping on the choice of sport of secondary school girls in Hong Kong Lo, Hing- yeung, Simon Lo, Hing-yeung, Simon 88Conference contributors vEditor's note Macfarlane, D.J. Macfarlane, D.J. iiParticipation in and attitudes towards sport and physical activity by male and female students entering the University of Hong Kong in 1993-94 Speak, M.A. Speak, M.A. Lindner, K.J. Lindner, K.J. 87Gender issues in sport and exercise Wells, Howard J.C. Wells, Howard J.C. viiiReliability of a questionnaire to investigate differences in habitual physical activity of Hong Kong primary school children - a pilot study MacFarlane, D.J. MacFarlane, D.J. Chan, M.K. Chan, M.K. 86A case study of female students' participation and attitudes towards school physical education and sport as compared with male students in one primary and one secondary school Ching, Wai-kin, Joe Ching, Wai-kin, Joe 85Changing the culture of sport White, Anita White, Anita 21Participation of females in physical activity and sports in ancient China Speak, M.A. Speak, M.A. 83Sports participation in Macau dyring transition period 1999 Wong, Shu-sing, Paul Wong, Shu-sing, Paul 84Introduction to gender issues in Hong Kong Pearson, Veronica Pearson, Veronica 34Inactivity of male & female children McManus, Alison McManus, Alison Armstrong, N. Armstrong, N. 35Gender differences in the experience of anxiety in competitive sport, among Hong Kong elite athletes Leahy, Trisha Leahy, Trisha Cheung, Fanny M. Cheung, Fanny M. 64Gender differences in the experience of anxiety in competitive sport among Hong Kong elite athletes Leahy, Trisha Leahy, Trisha 63Male and female sport participation in Hong Kong Sivan, Atara Sivan, Atara Roberston, Robert W. Roberston, Robert W. 56Promotion of female sport in schools Ip, Hay-wood Ip, Hay-wood 46Why Hong Kong female athletes perform better Chan, Amy Chan, Amy 40University entrants' opinions on gender and sport issues Lindner, K.J. Lindner, K.J. Speak, M.A. Speak, M.A. 82Gender relations in sport Loy, John W. Loy, John W.

Predicting sleep disordered breathing in outpatients with suspected OSA

Objective To validate the utilities of Berlin, STOP and STOP-BANG Questionnaires, other patient characteristics, comorbidities, Epworth Sleepiness Scale (ESS), fractional exhaled nitric oxide (FENO) and blood markers for the prediction of sleep disordered breathing (SDB) on limited polygraphy. Setting North Glasgow Sleep Service (a tertiary referral centre). Participants 129 consecutive patients, aged ≥16 years, referred to the sleep clinic for assessment of possible obstructive sleep apnoea. Interventions We selected cut-points of apnoea hypopnoea index (AHI) of ≥5 and ≥15/h from their home polygraphy and determined associations of these with individual symptoms, questionnaire scores and other results. Receiver operating characteristic analysis and univariate and multivariate logistic regression were used to explore these. Primary and secondary outcomes measures Primary: The utility of STOP, STOP-BANG and Berlin Questionnaires for prediction of SDB. Secondary: The utility of other measures for prediction of SDB. Results AHI was ≥5 in 97 patients and ≥15 in 56 patients. STOP and STOP-BANG scores were associated with both AHI cut-points but results with ESS and Berlin Questionnaire scores were negative. STOP-BANG had a negative predictive value 1.00 (0.77–1.00) for an AHI ≥15 with a score ≥3 predicting AHI ≥5 with sensitivity 0.93 (95% CI 0.84 to 0.98) and accuracy 79%, while a score ≥6 predicted AHI ≥15 with specificity 0.78 (0.65 to 0.88) and accuracy 72%. Neck circumference ≥17 inch and presence of witnessed apnoeas were independent predictors of SDB. Conclusions STOP and STOP-BANG Questionnaires have utility for the prediction of SDB in the sleep clinic population. Modification of the STOP-BANG Questionnaire merits further study in this and other patient groups.</p