New V control chart for the Maxwell distribution

Control charts have been popularly used as a user-friendly yet technically sophisticated tool to monitor whether a process is in statistical control or not. These charts are basically constructed under the normality assumption. But in many practical situations in real life this normality assumption may be violated. One such non-normal situation is to monitor the process variability from a skewed parent distribution where we propose the use of a Maxwell control chart. We introduce a pivotal quantity for the scale parameter of the Maxwell distribution which follows a gamma distribution. Probability limits and L-sigma limits are studied along with performance measure based on average run length and power curve. To avoid the complexity of future calculations for practitioners, factors for constructing control chart for monitoring the Maxwell parameter are given for different sample sizes and for different false alarm rate. We also provide simulated data to illustrate the Maxwell control chart. Finally, a real life example has been given to show the importance of such a control chart.     

Exploring youths' perceptions of the hidden practice of youth work in increasing social capital with young people considered NEET in Scotland

This small-scale research explores the generation of social capital in young people growing up in one urban area and one rural area in Scotland via community-led youth work projects that aim to re-engage young people categorised as NEET (Not in Employment Education or Training). By looking at their varied and complex biographies, it considers young people's experiences and perceptions of their communities and their transitions from education to the workplace. Using social capital as a theoretical lens, we examined the impact that youth work can have not just on these important transitions but also upon the young people themselves. By visiting two different sites of engagement we were able to explore whether the type of initiative (media or sports) or place (urban or rural) had an impact on the generation of capital for young people. The youth work practice in both areas acted as a glue between the young people and their communities, creating opportunities where the two could be bound together and relationships created. This occurred in both sites regardless of the area or type of initiative and confirmed in this study that youth work acts as a site of capital building.     

On the generalized process capability under simple and mixture models

Process capability (PC) indices measure the ability of a process of interest to meet the desired specifications under certain restrictions. There are a variety of capability indices available in literature for different interest variables such as weights, lengths, thickness, and the life time of items among many others. The goal of this article is to study the generalized capability indices from the Bayesian view point under different symmetric and asymmetric loss functions for the simple and mixture of generalized lifetime models. For our study purposes, we have covered a simple and two component mixture of Maxwell distribution as a special case of the generalized class of models. A comparative discussion of the PC with the mixture models under Laplace and inverse Rayleigh are also included. Bayesian point estimation of maintenance performance of the system is also part of the study (considering the Maxwell failure lifetime model and the repair time model). A real-life example is also included to illustrate the procedural details of the proposed method.     

An assessment of soil nematode food webs and nutrient pools in community gardens and vacant lots in two post-industrial American cities

In the midst of the current economic crisis, there is renewed interest in transforming vacant lots into food-producing gardens. This study analyzed whether vacant lots are suitable for food production, by comparing the soil nematode food webs and nutrient pools of vacant lots and community gardens in two post-industrial U.S. cities, Akron and Cleveland, Ohio. Twelve vacant lots and 12 community gardens were examined in the two cities. All six Akron community gardens were established just prior to the initiation of this study, whereas the six in Cleveland were 15–30 years old. Soil pH, texture, moisture, organic matter, mineral nitrogen content, microbial biomass, and nematode communities were measured in both cities. Soil decomposition rate was also measured in Cleveland. Results show that the soils of vacant lots surpassed those of the newly-established Akron gardens and were equal to the soils of the well-established Cleveland gardens in the amount of ammonium-nitrogen, total nematode population, genus diversity, and maturity and structure indices. The soils of the vacant lots were lower than the community gardens in the amounts of soil moisture, organic matter, and nitrate-nitrogen, which we associate with the addition of water, compost, fertilizer, and tilling in the gardens. No significant difference was found between community gardens and vacant lots in microbial biomass, decomposition rate, or nematode enrichment index, which seems to indicate that vacant lots are equal to community gardens in nutrient availability and nutrient cycling. We conclude that barring any contamination, the soil in vacant lots maybe suitable for the establishment of food gardens, which can provide many desirable ecosystem services and enhance human well-being. We also find that the disturbance associated with tillage and conversion of a vacant lot into a community garden has short-term ramifications for both nematode food webs and mineral-nitrogen content.     

Euthanasia and the medical profession: an Australian study

Advances in medical knowledge and technology are enabling more people to live longer in modern societies. This situation has also created dilemmas for medical practitioners in treating severely or chronically ill patients where the harm caused to them by treatment appears to outweigh the benefits. After reviewing some of the major legal and ethical issues confronting medical practitioners in Australia, this paper reports findings of a survey of Australian doctors' attitudes towards euthanasia. The findings show that a significant number of doctors receive requests from either the patients or their families to hasten death through active or passive euthanasia. A large majority of them also regard some form of passive euthanasia as an acceptable medical decision concerning the end of life. Twenty per cent of general practitioners and 17 per cent of specialists surveyed have taken active steps in the past to hasten the death of a patient. This paper explores the circumstances in which doctors are prepared to perform euthanasia and concludes with a discussion of the legal, ethical and professional issues raised by the survey's findings.     

A Bayesian way of monitoring the linear profiles using CUSUM control charts

In statistical process control applications, profiles functions are considered an efficient way of representing quality of products or processes. Classical and Bayesian thoughts are two chief sources of defining control charting structures for profiles monitoring. This Study introduces novel Bayesian CUSUM control structures for profiles monitoring. The comprehensive comparative study identifies that the proposed Bayesian CUSUM control charts under conjugate priors has better expected performance than competing methods. The implementation of Bayesian structures requires detailed information about process parameters which come up with considerable benefits. In addition, simulative example and case study further justified the superiority of proposed techniques.     

The experiences of breastfeeding mothers returning to work as hospital nurses in Pakistan: A qualitative study

Background

Pakistan has a higher infant mortality rate than countries with comparable economies, with around half of all under-5 deaths occurring in the first month of life. Breastfeeding is known to improve infant morbidity and mortality, but rates of formula feeding in Pakistan are increasing. Maternal employment is recognised globally as a major barrier to the continuation of breastfeeding.

Asian migrants in Australia: A socio‐economic study

This paper presents a socio‐economic profile of Asian migrants in Australia, using data from the 1981 Census of Population. It shows that Asian migrants are highly educated (large proportions are university graduates and are in professional occupations), English‐speaking (many are bi‐lingual) and mostly Christian. The paper then goes on to estimate the economic benefits Asian migrants bring when they migrate to Australia, as well as the costs they might impose on the economy. Benefits were estimated by measuring the costs of education and training that Australia avoided by allowing skilled migrants to enter the country. In addition, migrants brought in financial capital when they came to Australia. They also contributed to the supply of goods and services by participating in productive employment. The costs that migrants might impose on the economy relate to the possibility of taking jobs and other resources (such as education, health and other public services) which might otherwise have gone to other Australians. Careful estimates of these factors indicate that, far from imposing a burden, Asian migrants make a substantial net contribution to the economy. In addition, the findings do not lend support to the view that they may be a cause of societal dissention, or a threat to Australian democratic institutions. On the contrary, the social attributes they possess indicate that they are well placed to settle successfully, and to make a substantial contribution to the development of Australian society.     

Progressive Variance Control Charts for Monitoring Process Dispersion

In a process, the deviation from location or scale parameters affects the quality of the process and waste resources. So it is essential to monitor such processes for possible changes due to any assignable causes. Control charts are the most famous tool used to meet this intention. It is useless to monitor process location until the assurance that process dispersion is in-control. This study proposes some new two-sided memory control charts named as progressive variance (PV) control charts which are based on sample variance to monitor changes in process dispersion assuming normality of quality characteristic to be monitored. Simulation studies are made, and an example is discussed to evaluate the performance of the proposed charts. The comparison of the proposed chart is made with exponentially weighted moving average- and cumulative sum-type charts for process dispersion. The study shows that performance of the proposed charts are uniformly better than its competitors for detecting positive shifts while for detecting negative shift in the variance their performance is better for small shifts and reasonably good for moderated shifts.