An expectation transformer approach to predicate abstraction and data independence for probabilistic programs

In this paper we revisit the well-known technique of predicate abstraction to characterise performance attributes of system models incorporating probability. We recast the theory using expectation transformers, and identify transformer properties which correspond to abstractions that yield nevertheless exact bound on the performance of infinite state probabilistic systems. In addition, we extend the developed technique to the special case of "data independent" programs incorporating probability. Finally, we demonstrate the subtleness of the extended technique by using the PRISM model checking tool to analyse an infinite state protocol, obtaining exact bounds on its performance

Effect of thermal processing methods on the proximate composition, gross energy, minerals and ricin content of undecorticated castor oil seed (Ricinus communis)

The nutritive value of raw and thermal processed castor oil seed (Ricinus communis) was investigated using the following parameters; proximate composition, gross energy, mineral constituents and ricin content. Three thermal processing methods; toasting, boiling and soaking-and-boiling were used in the processing of the seed as a way of improving its nutritive value. The three methods achieved a drastic reduction in the ricin levels. Toasting, boiling and soaking-and-boiling reduced ricin level by 93.05%, 94.84% and 97.76% respectively. Apart from Iron and potassium the thermal processing methods significantly (

Multiphase contacting in PGM hydrometallurgy

This thesis describes hydrodynamic studies of the leach and solvent extraction stages of a Platinum Group Metal (PGM) hydrometallurgical flowsheet. The studies were motivated by the need to increase PGM throughput in Johnson Matthey’s PGM refining business. In the leach stage, key components in the feed are selectively dissolved using acids in a stirred tank before they are recovered by liquid-liquid (L-L) solvent extraction and finally purified. The work described in this thesis tackles four main areas: hydrodynamic studies of L-L PGM solvent extraction in both mixer and settler stages, whilst for the leach stage, studies of particle behaviour in gas evolving solid-liquid (S-L) reactions and gas-liquid-solid (GLS) characterisation by a novel Electrical Resistance Tomography (ERT) technique are performed. In the mixer-settler, the effects of impeller diameter, D, to vessel diameter, T, ratio (D/T), the phase flow ratio, cφ/dφ; (where cφis the continuous phase flow fraction and dφ is the dispersed phase flow fraction) and the specific power input,Tε, upon the droplet size distribution in a L-L system and their phase separation were investigated. Changing a smaller D/T impeller for a larger D/T impeller at constant P/V and cφ/dφincreased droplet size because the maximum shear rate decreased as a result of increasing ratio of impeller pumping capacity (Q) with tip speed (Utip). Changing a larger cφ/dφfor smaller cφ/dφat a fixed P/V and D/T impeller increased droplet size because turbulent dampening increased since the average density, ρ ∝ dφ. Meanwhile, Kolmogoroff-Hinze’s theory was shown to apply for the measured relationship between Tε and droplet size. A settler design criterion, which relates the dispersed phase concentration (Ca) in the dispersion band to the dispersed phase throughput (Qd/A) agreed with the model by Ryon et al. (1959). Ca was significantly dependent on P/V and Qd/A, whilst the effects of Qc/Qd (where Qc is the continuous phase flowrate and Qd is the dispersed phase flowrate) and D/T were minimal. Droplet size analysis of the sedimenting region of the dispersion band and dense packed layer revealed a transitional distribution of droplet sizes due to the counteracting effects of droplet sedimentation, hindered settling and droplet-droplet coalescence. Particle behaviour in gas evolving S-L systems were quantified using the Zwietering ‘just-suspended’ impeller speed (Njs) condition in a sponge nickel® and sodium hypochlorite system. The presence of gas caused Njs to increase, however a coherent relationship between Njs in an ungassed and gassed system 3 could not be easily ascertained. Further work with Positron Emission Particle Tracking (PEPT) was advised to quantify the relationship. A well-known electrical concept called skin effect, which describes how the effective resistance of an electrical conductor varies as the frequency of an alternating current (AC) increases and decreases, was used to investigate GLS behaviour via a novel ERT spectroscopic technique. The process relies on the change in effective resistance of conducting objects with changing AC frequency to selectively detect different phases. The concept was initially validated with static phantoms of a stainless steel and plume of gas before being applied to dispersible stainless steel particles and gas. ERT spectroscopy showed that two AC frequencies (0.3 kHz and 9.6 kHz) could successfully isolate and simultaneously detect the gas and solid phases at a fixed current. By subtracting solids and gas conductivity, the change in solids and gas holdup were obtained

The Simple Urine Bag as Wound Drain Post-Craniotomy in a Low-resource Neurosurgical Practice: A Personal 4-year Prospective Cohort Study

Background: In the face of the practical non-availability of custom-made surgical wound drain materials, many other substitutes are used in  developing countries. These substitutes have their draw backs from which the Uribag appears to be free. The main objectives: To present our experience with the use of this cheap and readily-available material as post craniotomy wound drain in a Nigerian neurosurgical unitMethods: A 4-year prospective cohort study of the effectiveness, outcome with use and complications of the Uribag as post craniotomy wound drain in a consecutive cohort of neurosurgical patients. Data analyzed include the patients’ brief demographics; the types of cranial surgery in which drain was used; the drain performance, and any associated untoward drain /wound events.Results: The drain was used for this purpose in 107 patients over 4 years. Nineteen have been excluded from this analysis because they died too soon post op for drain performance to be measured. The 88 patients analyzed included 60 males (68%); age range 11 days to 75 years.Cranial surgery was for trauma in 42% and for brain tumour resection and other cranial procedures in the rest. The drain output ranged from 40mls to 960mls and was in place for an average of 3 days. There was 1 episode (1.1%) of drain dislodgement; 3 of drain blockage (3.4%) and 5 cases (5.7%) of wound complication post drain removal. All wounds healed with primary intention otherwise.Conclusions: The Uribag is an effective, very cheap, and complication-free, closed tube wound drain substitute for cranial surgery.Keywords: postsurgical wound drain substitute, developing country, craniotomy, neurosurgery, Uriba

Living a burdensome and demanding life: a qualitative systematic review of the patients experiences of peripheral arterial disease

<div><p>Background</p><p>Peripheral arterial disease (PAD) has a significant negative impact on the quality of life of individuals. Understanding the experiences of people living with PAD will be useful in developing comprehensive patient-centred secondary prevention therapies for this population.</p><p>Aim</p><p>The aim of this study is to identify first-hand accounts of patients’ experiences of living with PAD.</p><p>Methods</p><p>Six databases (CINALH, PsyclNFO, MEDLINE, AMED, EMBASE, Social citation index/Science citation index via Web of Science (WOS)) and reference lists of identified studies were searched until September 2017 (updated February 2018). Qualitative studies reporting patients’ account of living with PAD were eligible for inclusion. A framework thematic synthesis was implemented.</p><p>Results</p><p>Fourteen studies with 360 participants were included. Pain and walking limitation were recurrent among the varied symptom descriptions. Patients’ ignorance and trivialisation of symptoms contributed to delays in diagnosis. Inadequate engagement in disease understanding and treatment decisions meant patients had poor attitudes towards walking treatments and unrealistic expectations about surgery. Depending on symptom progression, patients battle with walking impairment, powerlessness, and loss of independence which were a source of burden to them. Lack of disease understanding is central through patients’ journey with PAD and, although they subsequently began adaptation to long term living with PAD, many worried about their future.</p><p>Conclusions</p><p>Disease understanding is vital across the illness trajectory in patients with PAD. Although certain experiences are common throughout patient journey, some might be unique to a particular stage (e.g. unrealistic expectation about surgery, or rationale of walking in spite of pain in a supervised exercise program). Given that PAD is an overarching construct ranging from the mildest form of intermittent claudication to severe critical limb ischemia with ulceration and gangrene, consideration of important patient constructs specific to each stage of the disease may enhance treatment success. Systematic review registration CRD42017070417.</p></div

The effect of cultural diversity on employee productivity in work organizations in Port Harcourt, Nigeria

The thrust of this study is the investigation of the impact of culturaldifferences on the productivity of employees within organizations.Developments in science and technology have made it possible formodern work organizations to have people of variegated cultural backgrounds working together as employees. This variety in culturalbackground or cultural diversity creates challenges in the workplace which lead to conflicts and affect team work when not properly managed. This study sheds light therefore on how differences in cultural orientations can affect the productivity of employees and organizations. This usually arises because organizations channel most of their efforts to improving workers' skills and knowledge to the detriment of employees’ daily organizational experience, in terms of cultural differences. The quantitative research method was adopted for data collection. Chi-square analysis was used to test the hypotheses formulated and the findings presented and discussed.The findings show that cultural diversity significantly affects the ability of employees to build or work in teams. This consequently affects their productivity. Since conflict arising from cultural differences wastes time and reduces employee morale, this study recommends that organizations should strive to create organizational culture that not only incorporates and enhances the cultural diversity of its workforce composition, but also enables employees to build relationships and acknowledge each other regardless of their differences of origin and background.Keywords: Culture, Cultural Diversity, Employees, Organizations, Productivity

Understanding the intersection of culture, religion and gender on diversity management: a qualitative study of Nigerian hotels

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of DOCTOR OF PHILOSOPHYRecent attention has been drawn to human resource management within the Nigerian context, with increased interest in the improvement of organisational management practices to enable Nigeria to compete in an increasingly globalised economy (Fajana et al., 2011). Despite this, however, there is a distinct paucity of academic literature addressing the effects of culture and religion on gender equality in management within Nigerian organisations (Tiemo and Arubayi, 2012). Nigeria does not have an indigenous tradition of human resource management, and as a consequence, many of its management practices are imported alongside foreign investment and amalgamated with local practices (Fajana et al., 2011). Nigeria’s patriarchal culture and demographic context have significant implications on diversity management, and this reflects on the composition of the workforce (Tiemo and Arubayi, 2012). Qualitative data collected in Northern, Southern and Eastern regions of Nigeria through in-depth interviews were coded and analysed. The study found that hotels in Nigeria are still grappling with the problem of gender inequality with females’ career development suffering greatly under the burden of a patriarchal culture. Females are also made to take job responsibilities that reflect their positions in the society and households. Secondly, the intersecting factors of gender, religion and culture put severe pressures on women, which tend to have a negative impact on work-life balance. Thirdly, family responsibility and expectations deter females from seeking promotion to the higher level of hotel administration. Many females who attempt to ‘rebel’ against the standing cultural order find themselves in marriage crises. Finally, gender diversity management is not promoted in Nigerian hotels. The study makes contributions to theory and practice. It finds common ground for the application of hegemonic masculinity framework and intersectionality perspective in gender and management inquiries. The study recommends radical holistic change is required regarding policy, cultural, programmatic, attitudinal and social actions

Performance of Rabbit Fed Hausa Potato Tuber (Solenostemon rotundifolium) Meal (HPTM) at Graded Levels as Substitute to Maize

Twenty-four (24) crossbred (New Zealand Red X Chinchilla) rabbit aged 4 &ndash; 6 weeks made up of mixed sexes with average initial body weight of (1.82kg and 1.83kg) were used to evaluate the effect of different levels of Hausa potato tuber meal (HPTM) inclusion on their feed intake and growth performance. The rabbits were randomly allotted to four groups of six rabbits per group. Each group was replicated three times in a completely randomized design with each replicate having two (2) rabbits. The groups were fed diets containing 0%, 10%, 20% and 30% HPTM respectively and designated treatment I, II, III and IV respectively. The chemical composition of the test ingredient was determined prior to its inclusion in&nbsp; the diets. Data were collected on final body weight, average daily weight gain and feed conversion ratio. All data were subjected to one way analysis of variance. There were no significant (P&gt;0.05) difference in the above listed parameters. Rabbits fed diets III and IV is significantly (P&lt;0.05) higher than rabbits fed diets II in average daily feed intake, while rabbits fed diets I were statistically similar to those fed diets III and IV. The results suggest that 30% replacement of maize with Hausa potato tuber meal (HPTM) did not have any deleterious effects on the growth performance of rabbits and that the general trend showed that there was increase in growth of the experimental animal with increase in the level of Hausa potato tubers meal (HPTM).Keywords: Solenostemon rotundifolium meal, growth performance, crossbred rabbit

Quantitative Safety: Linking Proof-Based Verification with Model Checking for Probabilistic Systems

This paper presents a novel approach for augmenting proof-based verification with performance-style analysis of the kind employed in state-of-the-art model checking tools for probabilistic systems. Quantitative safety properties usually specified as probabilistic system invariants and modeled in proof-based environments are evaluated using bounded model checking techniques. Our specific contributions include the statement of a theorem that is central to model checking safety properties of proof-based systems, the establishment of a procedure; and its full implementation in a prototype system (YAGA) which readily transforms a probabilistic model specified in a proof-based environment to its equivalent verifiable PRISM model equipped with reward structures. The reward structures capture the exact interpretation of the probabilistic invariants and can reveal succinct information about the model during experimental investigations. Finally, we demonstrate the novelty of the technique on a probabilistic library case study