Ethnic identity in a globalised world:the German community in Richmond and Kingston since 1970

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Nonlinear spectral shaping and optical rogue events in fiber-based systems

We provide an overview of our recent work on the shaping and stability of optical continua in the long pulse regime. Fibers with normal group-velocity dispersion at all-wavelengths are shown to allow for highly coherent continua that can be nonlinearly shaped using appropriate initial conditions. In contrast, supercontinua generated in the anomalous dispersion regime are shown to exhibit large fluctuations in the temporal and spectral domains that can be controlled using a carefully chosen seed. A particular example of this is the first experimental observation of the Peregrine soliton which constitutes a prototype of optical rogue-waves. © 2012 Elsevier Inc. All rights reserved.

Pulse shaping in mode-locked ring-cavity fibre lasers

By means of extensive numerical modelling we have demonstrated the possibility of nonlinear pulse shaping in a mode-locked fibre laser using control of the intra-cavity propagation dynamics by adjustment of the normal net dispersion and integrated gain. Beside self-similar mode-locking, the existence of a novel type of pulse shaping regime that produces pulses with a triangular temporal intensity profile and a linear frequency chirp has been observed.

Adaptive pulse shaping through BER Feedback

We propose a simplified approach to optical signal pre-distortion based on adaptive pulse shaping through unconventional use of a MZ modulator. The scheme allows natural tailoring of transmitted pulses by optimising the received pulse.

Passive nonlinear pulse shaping in normally dispersive fiber

We propose a simple method for passive nonlinear optical pulse shaping that utilizes pulse prechirping and nonlinear propagation in a normally dispersive nonlinear fiber to generate various temporal waveforms of practical interest from conventional laser pulses.

Non-rectangular perfect reconstruction pulse shaping based ICI reduction in CO-OFDM

In this paper, we propose to increase residual carrier frequency offset tolerance based on short perfect reconstruction pulse shaping for coherent optical-orthogonal frequency division multiplexing. The proposed method suppresses the residual carrier frequency offset induced penalty at the receiver, without requiring any additional overhead and exhaustive signal processing. The Q-factor improvement contributed by the proposed method is 1.6 dB and 1.8 dB for time-frequency localization maximization and out-of-band energy minimization pulse shapes, respectively. Finally, the transmission span gain under the influence of residual carrier frequency offset is ̃62% with out-of-band energy minimization pulse shape. © 2014 Optical Society of America.

A multilevel study of the relationships between diversity training, ethnic discrimination and satisfaction in organizations

The prevalence of diversity training has not been matched by empirical research on its effectiveness. Among the most notable gaps are an absence of attention to its impact on discrimination and limited consideration of organizational-level factors. Results from employee surveys across 395 healthcare organizations reveal an effect of the extent of diversity training in organizations on ethnic minorities' experiences of discrimination. In addition, the results demonstrate that the consequences of ethnic discrimination for individuals' job attitudes are influenced by organizational-level phenomenon. These findings highlight the importance of attending to ethnic discrimination as an outcome of diversity training with implications for employee attitudes. © 2010 John Wiley & Sons, Ltd.

Nonlinear pulse shaping and polarization dynamics in mode-locked fiber lasers

We review our recent progress on the study of new nonlinear mechanisms of pulse shaping in passively mode-locked fiber lasers. These include a mode-locking regime featuring pulses with a triangular distribution of the intensity, and spectral compression arising from nonlinear pulse propagation. We also report on our recent experimental studies unveiling new types of vector solitons with processing states of polarization for multi-pulse and tightly bound-state soliton (soliton molecule) operations in a carbon nanotube (CNT) mode-locked fiber laser with anomalous dispersion cavity. © 2014 World Scientific Publishing Company.

Ethnic differences in health related quality of life for patients with type 2 diabetes

Background - The objective of this study was to investigate the association between ethnicity and health related quality of life (HRQoL) in patients with type 2 diabetes. Methods - The EuroQol EQ-5D measure was administered to 1,978 patients with type 2 diabetes in the UK Asian Diabetes Study (UKADS): 1,486 of south Asian origin (Indian, Pakistani, Bangladeshi or other south Asian) and 492 of white European origin. Multivariate regression using ordinary least square (OLS), Tobit, fractional logit and Censored Least Absolutes Deviations estimators was used to estimate the impact of ethnicity on both visual analogue scale (VAS) and utility scores for the EuroQol EQ-5D. Results - Mean EQ-5D VAS and utility scores were lower among south Asians with diabetes compared to the white European population; the unadjusted effect on the mean EQ-5D VAS score was −7.82 (Standard error [SE] = 1.06, p < 0.01) and on the EQ-5D utility score was −0.06 (SE = 0.02, p < 0.01) (OLS estimator). After controlling for socio-demographic and clinical confounders, the adjusted effect on the EQ-5D VAS score was −9.35 (SE = 2.46, p < 0.01) and on the EQ-5D utility score was 0.06 (SE = 0.04), although the latter was not statistically significant. Conclusions - There was a large and statistically significant association between south Asian ethnicity and lower EQ-5D VAS scores. In contrast, there was no significant difference in EQ-5D utility scores between the south Asian and white European sub-groups. Further research is needed to explain the differences in effects on subjective EQ-5D VAS scores and population-weighted EQ-5D utility scores in this context.

Respiratory function monitoring using a real-time three-dimensional fiber-optic shaping sensing scheme based upon fiber Bragg gratings

An array of in-line curvature sensors on a garment is used to monitor the thoracic and abdominal movements of a human during respiration. The results are used to obtain volumetric changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The array of 40 in-line fiber Bragg gratings is used to produce 20 curvature sensors at different locations, each sensor consisting of two fiber Bragg gratings. The 20 curvature sensors and adjoining fiber are encapsulated into a low-temperature-cured synthetic silicone. The sensors are wavelength interrogated by a commercially available system from Moog Insensys, and the wavelength changes are calibrated to recover curvature. A three-dimensional algorithm is used to generate shape changes during respiration that allow the measurement of absolute volume changes at various sections of the torso. It is shown that the sensing scheme yields a volumetric error of 6%. Comparing the volume data obtained from the spirometer with the volume estimated with the synchronous data from the shape-sensing array yielded a correlation value 0.86 with a Pearson's correlation coefficient p <0.01.

Pulse shaping in mode-locked fiber lasers by in-cavity spectral filter

We numerically show the possibility of pulse shaping in a passively mode-locked fiber laser by inclusion of a spectral filter into the laser cavity. Depending on the amplitude transfer function of the filter, we are able to achieve various regimes of advanced temporal waveform generation, including ones featuring bright and dark parabolic-, flat-top-, triangular- and saw-tooth-profiled pulses. The results demonstrate the strong potential of an in-cavity spectral pulse shaper for controlling the dynamics of mode-locked fiber lasers. © 2014 Optical Society of America.