Forces measured between latex spheres in aqueous electrolyte : Non-DLVO behavior and sensitivity to dissolved gas

An atomic force microscope was used to measure the forces acting between two polystyrene latex spheres in aqueous media. The results show an electrostatic repulsion at large separations which is overtaken by an attractive “hook” that pulls the two spheres into contact from a considerable range (20−400 nm), much larger than could be expected for a van der Waals attraction. The range of operation of this attraction varies from one experiment to another and is not correlated with electrolyte concentration. However, the range is found to decrease significantly when the level of dissolved gas in the water is reduced.

Climate change sensitivity of comfort and energy performance criteria for offices

The climate change scenarios of the Intergovernmental Panel on Climate Change (IPCC) predict a significant increase in temperatures over the next decades. Architecture and building occupants have to respond to this change, but little information is currently available in how far the predicted changes are likely to affect comfort and energy performance in buildings. This study therefore investigates the climate change sensitivity of the following parameters: adaptive thermal comfort according to Ashrae Standard 55 and EN 15251, energy consumption, heating and cooling loads, and length of heating and cooling periods. The study is based on parametric simulations of typical office room configurations in the context of Athens, Greece. They refer to different building design priorities and account for different occupant behaviour by using an ideal and worst case scenario. To evaluate the impact of the climate change, simulations are compared based on a common standard weather data set for Athens, and a generated climate change data set for the IPCC A2 scenario. The results show a significant impact of the climate change on all investigated parameters. They also indicate that in this context the optimisation of comfort and energy performance is likely to be related to finding the best possible balance between building (design) and occupant behaviour and other contextual influences, rather than a straightforward optimisation of separated single parameters.

Sensitivity of deformation twinning to grain size in titanium and magnesium

The impact of grain size on deformation twinning in commercial purity titanium and magnesium alloy Mg–3Al–1Zn (AZ31) is investigated. Tensile tests were carried out for the titanium samples; compression testing was employed for the magnesium specimens. Average values of the true twin length, true twin thickness and the number density of twins were determined using stereology. A key difference between these two materials is that twinning contributes little to the plastic strain in the titanium while it accounts for nearly all of the early plastic strain in the magnesium. In some respects (e.g. volume fraction and number density) the phenomenology of twinning differed between the two materials, while in others (e.g. twin shape and size) both materials showed a similar response. It is found that in both materials, twins span the entirety of their parent grains only for grain sizes less than ∼30 μm. Both the nucleation density per unit of nucleating interface (i.e. grain and twin boundaries) and the aspect ratio of twins scale with applied stress. The impact of grain size on twin volume fraction is modelled analytically.

Increasing the sensitivity of the AQoL inventory for the evaluation of interventions affecting mental health

This paper presents the rationale and psychometric analysis for extending the inventory of the Assessment of Quality of Life (AQoL)-6D instrument. The resulting AQoL-8D has an 8 dimensional, 35 item inventory with greater sensitivity in the domain of mental health.The paper briefly reviews the existing QoL instruments used for economic evaluation of health programs. It outlines the steps adopted in developing the AQoL descriptive inventories and, specifically, the methods adopted for data collection and analysis for the AQoL-8D inventory.Three instruments are presented. The first, PsyQoL, is a 22 item instrument which represents the best statistical fit for the measurement of mental health related quality of life. The second, PsyQoL-Brief is a reduced form instrument which is combined with AQoL-6D as the basis for the third instrument, the AQoL-8D. Psychometric properties of the first instrument are excellent and the second are good. The full AQoL-8D has satisfactory properties. Results from a comparison with the original AQoL-6D are reported. The mental health content of AQoL-8D is unique amongst MAU instruments and, along with other AQoL instruments, unique in its derivation from psychometric analysis. Its application to mental health patients and the public demonstrates its ability to discriminate between the groups with greater sensitivity than the previous AQoL-6D instrument.

Personality and the effort-reward imbalance model of stress : individual differences in reward sensitivity

The Effort-Reward Imbalance (ERI) model comprises both situational components (i.e. effort and reward) and a person-specific component (overcommitment). The aims of this study were to investigate the role of theoretically and historically linked personality variables (i.e. overcommitment and Type A personality) within the ERI model and to expand and extend the ERI model by investigating the contribution of individual reward components to both psychological (i.e. psychological distress) and attitudinal (i.e. affective commitment) employee strain indicators. A total of 897 police officers from a large Australian police agency participated in the study. The results provided no evidence of an interaction effect of effort or reward with overcommitment. The Type A variables did, however, make significant contributions and were involved in a number of interactions, suggesting that the person-specific component of the ERI model could be extended with the Type A personality profile. The findings also suggest that the esteem component of reward has the greatest relevance to employee outcomes, although tangible aspects of reward are more likely to act as a buffer of perceived work demand.

The letter contrast sensitivity test : clinical evaluation of a new design

PURPOSE. To compare the reliability, validity, and responsiveness of the Mars Letter Contrast Sensitivity (CS) Test to the Pelli-Robson CS Chart.

METHODS. One eye of 47 normal control subjects, 27 patients with open-angle glaucoma, and 17 with age-related macular degeneration (AMD) was tested twice with the Mars test and twice with the Pelli-Robson test, in random order on separate days. In addition, 17 patients undergoing cataract surgery were tested, once before and once after surgery.

RESULTS. The mean Mars CS was 1.62 log CS (0.06 SD) for normal subjects aged 22 to 77 years, with significantly lower values in patients with glaucoma or AMD (P < 0.001). Mars test-retest 95% limits of agreement (LOA) were ±0.13, ±0.19, and ±0.24 log CS for normal, glaucoma, and AMD, respectively. In comparison, Pelli-Robson test-retest 95% LOA were ±0.18, ±0.19, and ±0.33 log CS. The Spearman correlation between the Mars and Pelli-Robson tests was 0.83 (P < 0.001). However, systematic differences were observed, particularly at the upper-normal end of the range, where Mars CS was lower than Pelli-Robson CS. After cataract surgery, Mars and Pelli-Robson effect size statistics were 0.92 and 0.88, respectively.

CONCLUSIONS. The results indicate the Mars test has test-retest reliability equal to or better than the Pelli-Robson test and comparable responsiveness. The strong correlation between the tests provides evidence the Mars test is valid. However, systematic differences indicate normative values are likely to be different for each test. The Mars Letter CS Test is a useful and practical alternative to the Pelli-Robson CS Chart.

A multi-objective sensitivity approach to training providers' evaluation and quota allocation planning

The practice of solely relying on the human resources department in the selection process of external training providers has cast doubts and mistrust across other departments as to how trainers are sourced. There are no measurable criteria used by human resource personnel, since most decisions are based on intuitive experience and subjective market knowledge. The present problem focuses on outsourcing of private training programs that are partly government funded, which has been facing accountability challenges. Due to the unavailability of a scientific decision-making approach in this context, a 12-step algorithm is proposed and tested in a Japanese multinational company. The model allows the decision makers to revise their criteria expectations, in turn witnessing the change of the training providers' quota distribution. Finally, this multi-objective sensitivity analysis provides a forward-looking approach to training needs planning and aids decision makers in their sourcing strategy.