Semi batch learning with store management using enhanced conjugate gradient

This paper explores the performance of sliding-window based training, termed as semi batch, using multilayer perceptron (MLP) neural network in the presence of correlated data. The sliding window training is a form of higher order instantaneous learning strategy without the need of covariance matrix, usually employed for modeling and tracking purposes. Sliding-window framework is implemented to combine the robustness of offline learning algorithms with the ability to track online the underlying process of a function. This paper adopted sliding window training with recent advances in conjugate gradient direction with application of data store management e.g. simple distance measure, angle evaluation and the novel prediction error test. The simulation results show the best convergence performance is gained by using store management techniques. © 2012 Springer-Verlag.

Regional variation in five indicators of health in early childhood: a cohort study

Background Persistent and marked differences in adult morbidity and mortality between regions in the United Kingdom (UK) are often referred to as the north-south gradient (or divide) and the Scottish effect, and are only partly explained by adult levels of socioeconomic status (SES) or risk factors which suggests variation arising earlier in life. The aim of the current study was to examine regional variations in five health indicators in children in England and Scotland at birth and three years of age.
Methods Respondents were 10,500 biological Caucasian mothers of singleton children recruited to the Millennium Cohort Study (MCS). Outcome variables were: gestational age and weight at birth, and height, body mass index (BMI), and externalising behaviour at age three. Region/Country was categorised as: South (reference), Midlands, North, and Scotland. Respondents provided information on child, maternal, household, and socioeconomic characteristics when the cohort infant/child was aged nine months and again when aged three years. 
Results There were no significant regional variations for gestational age or birthweight. However, at age three there was a north-south gradient for externalising behaviour and a north-south divide in BMI which attenuated on adjustment. However, a north-south divide in height was not fully explained by the adjusted model. There was also evidence of a ‘Midlands effect’, with increased likelihoods of shorter stature and behaviour problems. Results showed a Scottish effect for height and BMI in the unadjusted models, and height in the adjusted model. However, Scottish children were less likely to show behaviour problems in crude and adjusted models. 
Conclusions Findings indicated no marked regional differences in children at birth, but by age three some regional health differences were evident, and though not distinct north-south gradients or Scottish effects, are evidence of health inequalities appearing at an early age and dependent on geographic location.

Electromagnetic Focusing and Imaging in Stratified Media Using Gradient Phase Profiled Conjugating Lens

High-resolution imaging of a dipole source in stratified medium based on negative refraction is presented in this paper. Compensation of the material parameter contrast at the stratified media interface is achieved using a gradient phase profiled conjugating lens (GPCL). It is shown both analytically and numerically that the phase gradient applied across the GPCL positioned at the interface of vertically stratified media enables a high-quality image of a dipole source in a mirror symmetric position with respect to the lens plane. The analytical closed form expression of the phase gradient function is derived using Huygens-Kirchhoff principle. The result is applicable to media with arbitrary stratification and material parameters, including lossy materials. The mechanism for formation of the dipole image in the stratified medium and aberration due to the dielectric contrast at the interface, particularly electromagnetic loss, is discussed in detail. The efficacy of gradient phase and amplitude aberration compensations mechanisms available through the GPCL is articulated. The results of the study are of importance in a wide range of imaging problems in stratified media for medical, civil, and military applications.

Direct Observation of Density-Gradient Effects in Harmonic Generation from Plasma Mirrors

High-order harmonics and attosecond pulses of light can be generated when ultraintense, ultrashort laser pulses reflect off a solid-density plasma with a sharp vacuum interface, i.e., a plasma mirror. We demonstrate experimentally the key influence of the steepness of the plasma-vacuum interface on the interaction, by measuring the spectral and spatial properties of harmonics generated on a plasma mirror whose initial density gradient scale length L is continuously varied. Time-resolved interferometry is used to separately measure this scale length. 

GRADIENT CORRECTIONS IN DENSITY-FUNCTIONAL THEORY CALCULATIONS FOR SURFACES - CO ON PD(110)

Ab initio total energy calculations have been performed for CO chemisorption on Pd(110). Local density approximation (LDA) calculations yield chemisorption energies which are significantly higher than experimental values but inclusion of the generalised gradient approximation (GGA) gives better agreement. In general, sites with higher coordination of the adsorbate to surface atoms lead to a larger degree of overbinding with LDA, and give larger corrections with GGA. The reason is discussed using a first-order perturbation approximation. It is concluded that this may be a general failure of LDA for chemisorption energy calculations. This conclusion may be extended to many surface calculations, such as potential energy surfaces for diffusion.

Higher effort-reward imbalance and lower job control predict exit from the labour market at the age of 61 years or younger: Evidence from the English Longitudinal Study of Ageing

Background: We examined whether higher effort-reward imbalance (ERI) and lower job control are associated with exit from the labour market. 

Methods: There were 1263 participants aged 50-74 years from the English Longitudinal Study on Ageing with data on working status and work-related psychosocial factors at baseline (wave 2; 2004-2005), and working status at follow-up (wave 5; 2010-2011). Psychosocial factors at work were assessed using a short validated version of ERI and job control. An allostatic load index was formed using 13 biological parameters. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Exit from the labour market was defined as not working in the labour market when 61 years old or younger in 2010-2011. 

Results: Higher ERI OR=1.62 (95% CI 1.01 to 2.61, p=0.048) predicted exit from the labour market independent of age, sex, education, occupational class, allostatic load and depression. Job control OR=0.60 (95% CI 0.42 to 0.85, p=0.004) was associated with exit from the labour market independent of age, sex, education, occupation and depression. The association of higher effort OR=1.32 (95% CI 1.01 to 1.73, p=0.045) with exit from the labour market was independent of age, sex and depression but attenuated to non-significance when additionally controlling for socioeconomic measures. Reward was not related to exit from the labour market. 

Conclusions: Stressful work conditions can be a risk for exiting the labour market before the age of 61 years. Neither socioeconomic position nor allostatic load and depressive symptoms seem to explain this association.

The validity of critical thinking tests for predicting degree performance: A longitudinal study

This study explored the validity of using critical thinking tests to predict final psychology degree marks over and above that already predicted by traditional admission exams (A-levels). Participants were a longitudinal sample of 109 psychology students from a university in the United Kingdom. The outcome measures were: total degree marks; and end of year marks. The predictor measures were: university admission exam results (A-levels); critical thinking test scores (skills & dispositions); and non-verbal intelligence scores. Hierarchical regressions showed A-levels significantly predicted 10% of the final degree score and the 11-item measure of ‘Inference skills’ from the California Critical Thinking Skills Test significantly predicted an additional 6% of degree outcome variance. The findings from this study should inform decisions about the precise measurement constructs included in aptitude tests used in the higher education admission process.