Using On-Line Quizzes to Help Students Learn Probability and Statistics

Online quizzes can be an effective and flexible means of helping learners develop key skills in probability and statistics. Quizzes give instant feedback, to help reinforce correct understanding and eliminate fundamental errors at an early stage in learning. We will describe our experience of designing and using quizzes with non-specialist and specialist students, on several different platforms including, most recently, Moodle. We describe Model Choice, a tool that helps students identify from a brief scenario the standard family of probability distributions they should work with to solve a problem. We will emphasize key design aspects of a successful quiz system, such as the importance of giving informative feedback to the learner. Using a standard platform, such as Moodle, is likely to require some compromise on design principles but building a stand-alone system to implement ideal design choices is very time-consuming

Estimation of Bearing Forces in Rotating Machinery: A Problem Revisited

Development of a new ship machinery installation may require combinations of prime movers, electric motors, generators, gearboxes and other items that have not been used previously. Large items of this type are expensive to develop, so that only existing production items are likely to be affordable. Modern quiet ship design requires careful attention to the source characteristics of the individual machinery items as well as the dynamic characteristics of any new combination, so that fluctuating forces transmitted to the hull via mounting systems and flexible connectors in the final installation are within acceptable limits. Almost periodic components, which arise at multiples of machine rotational frequency, are of particular concern. Machine source properties are often known only in terms of the vibration characteristics of previous installations, not in terms of the disturbing forces that cause that vibration. The aim of the techniques described in this paper is to allow deduction of those disturbing forces from a matrix of transfer functions at each frequency of interest, measured with an existing machine in operation. The number of forces to be estimated must be less than the number of structural degrees of freedom. Those degrees of freedom arise from rigid body motions and machine flexural properties, which may change significantly when shafts are rotating. Also, the matrices must be redundant in order to allow estimation of the accuracy of derived force estimates. The larger the machine, the greater the number of degrees of freedom that are likely to arise at a given frequency. A first use of the methodology was to establish the bearing forces in a marine turbo generator (TG) set with plain journal bearings. Measurements of transfer functions were made with the machine stationary and then with the machine in normal operation. Direct and reciprocal measurements in different directions were made for a large number of locations on the machine structure and bearings, covering the frequency range up to more than twice shaft rotational frequency. There were large differences in some frequency ranges between the static and operational conditions. Vibration due to machine operation was then measured to allow deduction of bearing forces using the transfer function matrices. Repeat measurements were made to establish whether machine source properties changed significantly with time, while statistical techniques were also used to identify and eliminate any suspect measurements. Those early experiments are described in this paper with a view to future application of similar techniques

The Experience of Teaching Statistics to Non-Specialist Students in Saudi Universities: The Role of Technology and Language

The importance of statistics is not limited to statisticians but also impacts on non-statisticians who have to use statistics. One important issue is how statistics is best taught to, and learned by, non-specialist students. The pervasive use of the English language causes additional challenges to learners whose first language is not English, especially when technological resources that use English language, such as statistics software packages, are an integral part of the course. This paper presents research into the current position in Saudi universities, where there has previously been a lack of research into this topic. Mixed methods research has been used: a questionnaire survey of 1,053 students and qualitative interviews with 16 teachers of statistics from all colleges within all six universities where statistics is taught to non-specialist students in Saudi Arabia’s Eastern Region. This presentation will discuss differences between the experiences of learners taught in the Arabic and English languages

Performance indicators for primary care groups; an evidence-based approach

The NHS Executive and Department of Health have proposed a wide range of performance indicators many of which are applicable to future primary care groups Some of these indicators reflect access and efficiency, but few of the effectiveness indicators are based on primary care interventions for which there is evidence that increased uptake results in improved health outcomes We present a method to identify important primary care interventions of proved efficacy and suggest performance indicators that could monitor their use Our evidence based approach may be a complementary way of identifying areas for performance indicators to those proposed by the NHS Executive and Department of Health Our suggested indicators are more likely to help turn evidence into everyday practice and to have an impact on the population's healt

Estimation of Bearing Forces in Rotating Machinery: A Problem Revisited

Development of a new ship machinery installation may require combinations of prime movers, electric motors, generators, gearboxes and other items that have not been used previously. Large items of this type are expensive to develop, so that only existing production items are likely to be affordable. Modern quiet ship design requires careful attention to the source characteristics of the individual machinery items as well as the dynamic characteristics of any new combination, so that fluctuating forces transmitted to the hull via mounting systems and flexible connectors in the final installation are within acceptable limits. Almost periodic components, which arise at multiples of machine rotational frequency, are of particular concern. Machine source properties are often known only in terms of the vibration characteristics of previous installations, not in terms of the disturbing forces that cause that vibration. The aim of the techniques described in this paper is to allow deduction of those disturbing forces from a matrix of transfer functions at each frequency of interest, measured with an existing machine in operation. The number of forces to be estimated must be less than the number of structural degrees of freedom. Those degrees of freedom arise from rigid body motions and machine flexural properties, which may change significantly when shafts are rotating. Also, the matrices must be redundant in order to allow estimation of the accuracy of derived force estimates. The larger the machine, the greater the number of degrees of freedom that are likely to arise at a given frequency. A first use of the methodology was to establish the bearing forces in a marine turbo generator (TG) set with plain journal bearings. Measurements of transfer functions were made with the machine stationary and then with the machine in normal operation. Direct and reciprocal measurements in different directions were made for a large number of locations on the machine structure and bearings, covering the frequency range up to more than twice shaft rotational frequency. There were large differences in some frequency ranges between the static and operational conditions. Vibration due to machine operation was then measured to allow deduction of bearing forces using the transfer function matrices. Repeat measurements were made to establish whether machine source properties changed significantly with time, while statistical techniques were also used to identify and eliminate any suspect measurements. Those early experiments are described in this paper with a view to future application of similar techniques

Foot related impairments and disability in juvenile idiopathic arthritis persist despite modern day treatment paradigms

Background: Foot problems such as synovitis, growth disturbance and deformity are considered common in juvenile idiopathic arthritis (JIA) and have been previously reported in over 90% of cases. The medical management of JIA appears to have improved recently however little is known about the impact of new regimes on localised joints such as in the foot. This pilot study aimed to investigate the prevalence of foot related impairments and disability, and survey the medical and podiatric management of patients in a cohort of UK children with JIA. Methods: This study was a tertiary care based cross-sectional survey. Thirty consecutive JIA patients with a history of foot and ankle arthritis completed the juvenile arthritis foot disability index questionnaire (JAFI) (0-4 for each domain), child health assessment questionnaire (CHAQ) (0-3), and pain visual analogue scale (VAS) (0-100mm). Foot deformity score (0-38), active and limited joint counts (0-77) and walking speed (m/s) were measured also recorded. Foot care provision over the previous 12 months was determined from the medical records in 23/ 30 participants. Results were analysed using simple descriptive statistics and expressed as median (range). Results: Children received biologic agents in 35%, DMARDs in 65%, and 90% of participants had received multiple intra-articular cortico-steroid injections. Median (range) values for foot disease outcomes were JAFI impairment = 1 (0-3), JAFI activity limitation = 1 (0-4) JAFI participation restriction 1 (0-3), CHAQ = 0.38 (0-2), VAS pain = 22 (0-79), foot deformity = 6 (0-20), active joints = 0 (0-7), limited joints (0-31), walking speed = 1.09 (0.84- 1.38). The JAFI scores represent mild foot related impairment and disability. Gait defects, deformity or abnormal foot posture, and/or active foot disease were the main reasons for referral. 43% of children received specialist podiatry care comprising footwear advice, orthotic therapy, and silicone digital appliances together with intrinsic muscle strengthening exercises. Conclusions: Despite DMARD/biologic regimes and specialist podiatry, foot related impairment and disability persists in JIA children. Foot care appears to be in line with current recommendations. Further study is required to determine the long-term consequences of these changes found during childhood in the foot

Low dose rituximab is no less effective for nephrotic syndrome measured by 12-month outcome

Objective: Rituximab is an effective treatment for children with steroid dependent or frequently relapsing nephrotic syndrome. The optimum dosing schedule for rituximab has not been established. We hypothesized that a single low dose of 375 mg/m2 would have comparable outcomes to higher doses in reducing the frequency of relapse and time to B cell reconstitution. Methods: We conducted a multicenter retrospective observational cohort study of children with steroid-sensitive frequently relapsing nephrotic syndrome. Data were extracted from clinical records including the dates of diagnosis, treatment, relapses, the use of concomitant immunosuppression, and lymphocyte subset profiling. Patients treated earlier received variable doses of rituximab, although typically two doses of 750 mg/m2. Later, patients received the current regimen of a single dose of 375 mg/m2. The primary outcome was an absence of clinically confirmed relapse 12 months following rituximab administration. Secondary outcomes were median time to relapse, probability of being relapse-free at 6 and 24 months and time to reconstitution of CD19+ B cells. Results: Sixty patients received 143 courses of rituximab. Seven different dosing regimen strategies were used, ranging between 375 and 750 mg/m2 per dose, with administration of 1–4 doses. There was no significant difference in event-free survival at 12 months between dosing strategies. The median time to reconstitution of B cells was not significantly different between groups. Conclusions: Use of a single low-dose regimen of rituximab in the management of frequently relapsing nephrotic syndrome does not affect the probability of relapse at 12 months or time to B cell reconstitution compared to a conventional higher dose

DySCo: Quantitating Associations of Membrane Proteins Using Two-Color Single-Molecule Tracking

We present a general method called dynamic single-molecule colocalization for quantitating the associations of single cell surface molecules labeled with distinct autofluorescent proteins. The chief advantages of the new quantitative approach are that, in addition to stable interactions, it is capable of measuring nonconstitutive associations, such as those induced by the cytoskeleton, and it is applicable to situations where the number of molecules is small

Promising Functional Readouts of Immunity in a Blood-Stage Malaria Vaccine Trial

The authors discuss results from an early trial of a vaccine based on Plasmodium MSP-3 protein reported by Pierre Druilhe and colleagues