On the conditional distribution of the mean of the two closest among a set of three observations

Chemical analyses of raw materials are often repeated in duplicate or triplicate. The assay values obtained are then combined using a predetermined formula to obtain an estimate of the true value of the material of interest. When duplicate observations are obtained, their average typically serves as an estimate of the true value. On the other hand, the "best of three" method involves taking three measurements and using the average of the two closest ones as estimate of the true value. In this paper, we consider another method which potentially involves three measurements. Initially two measurements are obtained and if their difference is sufficiently small, their average is taken as estimate of the true value. However, if the difference is too large then a third independent measurement is obtained. The estimator is then defined as the average between the third observation and the one among the first two which is closest to it. Our focus in the paper is the conditional distribution of the estimate in cases where the initial difference is too large. We find that the conditional distributions are markedly different under the assumption of a normal distribution and a Laplace distribution

On the conditional distribution of the mean of the two closest among a set of three observations

Chemical analyses of raw materials are often repeated in duplicate or triplicate. The assay values obtained are then combined using a predetermined formula to obtain an estimate of the true value of the material of interest. When duplicate observations are obtained, their average typically serves as an estimate of the true value. On the other hand, the "best of three" method involves taking three measurements and using the average of the two closest ones as estimate of the true value. In this paper, we consider another method which potentially involves three measurements. Initially two measurements are obtained and if their difference is sufficiently small, their average is taken as estimate of the true value. However, if the difference is too large then a third independent measurement is obtained. The estimator is then defined as the average between the third observation and the one among the first two which is closest to it. Our focus in the paper is the conditional distribution of the estimate in cases where the initial difference is too large. We find that the conditional distributions are markedly different under the assumption of a normal distribution and a Laplace distribution.Comment: 12 pages, 6 figure

The size of two-body weakly bound objects : short versus long range potentials

The variation of the size of two-body objects is investigated, as the separation energy approaches zero, with both long range potentials and short range potentials having a repulsive core. It is shown that long range potentials can also give rise to very extended systems. The asymptotic laws derived for states with angular momentum l=1,2 differ from the ones obtained with short range potentials. The sensitivity of the asymptotic laws on the shape and length of short range potentials defined by two and three parameters is studied. These ideas as well as the transition from the short to the long range regime for the l=0 case are illustrated using the Kratzer potential.Comment: 5 pages, 3 figures, submitted to Physical Review Letter

Examining the link between the antecedents of relationship commitment and loyalty within the road transport industry of South Africa

Abstract: The study investigates the extent to which the relationship commitment by customers of road transport service providers is influenced by trust, communication, shared values and the attractiveness of alternatives. In turn, the influence of the extent of their commitment towards future loyalty is determined. Design/methodology/approach – An explanatory research design was followed and data was collected from road transport service provider customers using self-administered questionnaires. A total of 120 responses were suitable for analysis. Multiple regression analysis as well as the one-way analysis of variance (ANOVA) technique was used to analyse the results and to uncover the interrelationships between constructs..

Urban integration of aeroelastic belt for low-energy wind harvesting

In this modern age low-energy devices are pervasive especially when considering their applications in the built-environment. The multitude of low-energy applications extend from wireless sensors, radio-frequency transceivers, charging devices, cameras and other small-scale electronic devices. The energy consumptions of these devices range in the milliwatt and microwatt scale which is a result of continuous development of these technologies. Thus, renewable wind energy harnessed from the aeroelastic effect can play a pivotal role in providing sufficient power for extended operation with little or no battery replacement. An aeroelastic belt is a simple device composed of a tensioned membrane coupled to electromagnetic coils and power conditioning components. This simplicity of the aeroelastic belt translates to its low cost and overall modularity. The aim of this study is to investigate the potential of integrating the aeroelastic belt into the built environment using Computational Fluid Dynamics (CFD) simulations. The work will investigate the effect of various external conditions (wind speed, wind direction and physical parameters, positioning and sizing) on the performance of the aeroelastic belt. The results from this study can be used for the design and integration of low-energy wind generation technologies into buildings

A retrospective review of genital fistula occurrence in nine African countries

Background: Female genital fistulas are abnormal communications that lead to urinary and/or fecal incontinence. This analysis compares the characteristics of women with fistulas to understand how countries differ from one another in the circumstances of genital fistula development. Methods: This retrospective records review evaluated demographics and circumstances of fistula development for 6,787 women who sought fistula treatment between 1994 and 2017 in Tanzania, Uganda, Kenya, Malawi, Rwanda, Somalia, South Sudan, Zambia, and Ethiopia. Results: Most women developed fistula during childbirth, whether vaginal (3,234/6,787, 47.6%) or by cesarean section (3,262/6,787, 48.1%). Others had fistulas attributable to gynecological surgery (215/6,787, 3.2%) or rare causes (76/6,787, 1.1%). Somalia, South Sudan, and Ethiopia had comparatively high proportions following vaginal birth and birth at home, where access to care was extremely difficult. Fistulas with live births were most common in Kenya, Malawi, Rwanda, Uganda, Tanzania, and Zambia, indicating more easily accessible care. Conclusions: Characteristics of women who develop genital fistula point to geographic differences in obstetric care. Access to care remains a clear challenge in South Sudan, Somalia, and Ethiopia. Higher proportions of fistula after cesarean birth and gynecological surgery in Kenya, Malawi, Rwanda, Uganda, Tanzania, and Zambia signal potential progress in obstetric fistula prevention while compelling attention to surgical safety and quality of care

Designing multiplayer games to facilitate emergent social behaviours online

This paper discusses an exploratory case study of the design of games that facilitate spontaneous social interaction and group behaviours among distributed individuals, based largely on symbolic presence 'state' changes. We present the principles guiding the design of our game environment: presence as a symbolic phenomenon, the importance of good visualization and the potential for spontaneous self-organization among groups of people. Our game environment, comprising a family of multiplayer 'bumper-car' style games, is described, followed by a discussion of lessons learned from observing users of the environment. Finally, we reconsider and extend our design principles in light of our observations

Sensitivity of Cross Sections for Elastic Nucleus-Nucleus Scattering to Halo Nucleus Density Distributions

In order to clear up the sensitivity of the nucleus-nucleus scattering to the nuclear matter distributions of exotic halo nuclei, we have calculated differential cross sections for elastic scattering of the $^6$He and $^{11}$Li nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon with different assumed nuclear density distributions in $^6$He and $^{11}$Li.Comment: 10 pages, 7 figures. Submitted to Proceedings of the 61 International Conference "Nucleus-2011" on the Problems of the Nuclear Spectroscopy and the Atomic Nuclear Structure, Sarov Nijzegorodskaya district, October 10-14, 201

The importance of customer trust for social marketing interventions : a case of energy-efficiency consumption

Abstract: Purpose – The study examines the importance of relationship marketing and particularly customer trust in energy-efficiency labels in social marketing interventions geared towards energy-efficient consumption. Methodology – A conceptual model was empirically tested on a sample of 517 users of electronic appliances living in South Africa. The study involved a cross-sectional design, and data were collected through a self-administered survey. Structural equation modelling and mediation analysis were used to test the hypothesised relationships. Findings – The results indicated that customer trust is influenced by customers’ perception of the price and quality of energy-efficiency products, their attitude towards such products, and their level of satisfaction with the environmental performance of the products. Customer trust, in turn, showed a positive influence on the customers’ intention to purchase energy-efficiency products and their loyalty to such products. As a central variable, customer trust was found to be an important mediator in the conceptual model. Practical implications – The findings provide social marketers with important insights on the critical role that customer trust plays in achieving a long-term behavioural shift towards energy-efficient consumption. Originality/value – Focusing on customer trust in energy-efficiency labels, this study provides empirical evidence of the mediating role of trust in influencing the intention to purchase and the decision to remain loyal to eco-friendly products. Moreover, this paper provides greater clarity on various levers to be activated to enhance the trust that customers have in energy-efficiency labels

Normative influence on household waste separation : the moderating effect of policy implementation and sociodemographic variables

Abstract: Background. With the increasing production of domestic waste in South African urban areas, household waste separation has become a crucial recycling activity for better management of domestic waste and a decrease in environmental pollution. Focus of the article. This empirical study investigates how normative influences can shape the intention to separate household waste, and how these influences are moderated by sociodemographic attributes and upstream social marketing interventions (recycling policy implementation). Research Hypotheses: The hypotheses stipulate that descriptive, injunctive and moral norms have an influence on the behavioral intention to separate household waste before disposal. Policy implementation and sociodemographic variables moderate the impact of these normative forces on behavioral intention. Methods. A cross-sectional design was applied to this study. A survey was administered to collect quantitative data from 350 households residing in a city that is currently implementing a mandatory recycling policy (Johannesburg) and from 349 households in a city that is not doing..