Optimal Class Size, Opt-Out Rights, and Indivisible Remedies

Prepared for a Symposium on the ALI’s Aggregate Litigation Project, this paper examines the ALI’s proposal to permit opt-out rights when remedies and “divisible,” but not to permit them when remedies are “indivisible.” Starting from the ground up, the paper employs economic analysis to determine what the optimal size of a class action should be. We demonstrate that, in some circumstances, the optimal size of a class is a class composed of all victims, while in other cases, the optimal size is smaller. We further argue that courts should consider optimal class size in determining whether to certify a class, and that there should be no opt-out right when a class is optimally sized. The ALI’s approach does not always lead to the most efficiently sized class actions

Quantifying Threat or Challenge Response of Undergraduate Paramedicine Students During High-Stress Clinical Scenarios - A Narrative Review

Paramedic work can be stressful. Encountering clinically unwell patients, long shift hours and dealing with the unknown expose paramedics to mental, physical and emotional stress. In the learning environment, these types of stresses are difficult for educators to replicate. Traditionally, students have been tested under pressure in scenario-based situations as a means of stress inoculation. However, the literature is unclear as to whether this enhances or hinders learning. A recent scoping review identified an acceptable level of stress during simulation can be beneficial, although a level of a balance is required. Too much stress can hinder learning and lead to underperformance. Ideally, high-acuity patient scenarios should be designed to invoke a challenging state of appraisal in the student to support both their learning and knowledge retention. To obtain an understanding of how students appraise these types of scenarios, quantitative physiological and psychometric data needs to be obtained and analyzed. However, across the health care education literature, inconsistent methodologies and a variety of physiological and cognitive measures make it challenging to draw firm conclusions. This narrative review searched three prominent databases using common search terms to produce a subset of high-quality publications that we thought were most pertinent and insightful. Our paper establishes recommendations for appropriate physiological assessment and interpterion of challenge appraisal in students undertaking high-stress, low-frequency clinical scenarios

Too stressed to think? A scoping review of the literature for healthcare educators utilising high acuity clinical scenarios.

The practise of paramedicine can be highly stressful particularly where urgent lifesaving decisions need to be made. Traditionally, educators have adopted the approach of placing students in simulated stressful situations as a way of learning to cope with these challenges. It is unclear from the literature whether traditional stress inoculation enhances or hinders learning. This scoping review aims to identify and examine both the peer-reviewed and grey literature reporting physiological stress responses to high-acuity scenarios in paramedicine and cognate healthcare disciplines

Investigating portable fluorescent microscopy (CyScope®) as an alternative rapid diagnostic test for malaria in children and women of child-bearing age

<p>Abstract</p> <p>Background</p> <p>Prompt and correct diagnosis of malaria is crucial for accurate epidemiological assessment and better case management, and while the gold standard of light microscopy is often available, it requires both expertise and time. Portable fluorescent microscopy using the CyScope^®offers a potentially quicker, easier and more field-applicable alternative. This article reports on the strengths, limitations of this methodology and its diagnostic performance in cross-sectional surveys on young children and women of child-bearing age.</p> <p>Methods</p> <p>552 adults (99% women of child-bearing age) and 980 children (99% ≤ 5 years of age) from rural and peri-urban regions of Ugandan were examined for malaria using light microscopy (Giemsa-stain), a lateral-flow test (Paracheck-Pf^®) and the CyScope^®. Results from the surveys were used to calculate diagnostic performance (sensitivity and specificity) as well as to perform a receiver operating characteristics (ROC) analyses, using light microscopy as the gold-standard.</p> <p>Results</p> <p>Fluorescent microscopy (qualitative reads) showed reduced specificity (<40%), resulting in higher community prevalence levels than those reported by light microscopy, particularly in adults (+180% in adults and +20% in children). Diagnostic sensitivity was 92.1% in adults and 86.7% in children, with an area under the ROC curve of 0.63. Importantly, optimum performance was achieved for higher parasitaemia (>400 parasites/μL blood): sensitivity of 64.2% and specificity of 86.0%. Overall, the diagnostic performance of the CyScope was found inferior to that of Paracheck-Pf^®.</p> <p>Discussion</p> <p>Fluorescent microscopy using the CyScope^®is certainly a field-applicable and relatively affordable solution for malaria diagnoses especially in areas where electrical supplies may be lacking. While it is unlikely to miss higher parasitaemia, its application in cross-sectional community-based studies leads to many false positives (i.e. small fluorescent bodies of presently unknown origin mistaken as malaria parasites). Without recourse to other technologies, arbitration of these false positives is presently equivocal, which could ultimately lead to over-treatment; something that should be further explored in future investigations if the CyScope^®is to be more widely implemented.</p

Two-year longitudinal survey reveals high genetic diversity of Schistosoma mansoni with adult worms surviving praziquantel treatment at the start of mass drug administration in Uganda

Background: A key component of schistosomiasis control is mass drug administration with praziquantel. While control interventions have been successful in several endemic regions, mass drug administration has been less effective in others. Here we focus on the impact of repeated praziquantel treatment on the population structure and genetic diversity of Schistosoma mansoni. Methods: We examined S. mansoni epidemiology, population genetics, and variation in praziquantel susceptibility in parasites isolated from children across three primary schools in a high endemicity region at the onset of the Ugandan National Control Programme. Children were sampled at 11 timepoints over two years, including one week and four weeks post-praziquantel treatment to evaluate short-term impacts on clearance and evidence of natural variation in susceptibility to praziquantel. Results: Prevalence of S. mansoni was 85% at baseline. A total of 3576 miracidia larval parasites, isolated from 203 individual children, were genotyped at seven loci. Overall, genetic diversity was high and there was low genetic differentiation, indicating high rates of parasite gene flow. Schistosome siblings were found both pre-treatment and four weeks post-treatment, demonstrating adult worms surviving treatment and natural praziquantel susceptibility variation in these populations at the beginning of mass drug administration. However, we did not find evidence for selection on these parasites. While genetic diversity decreased in the short-term (four weeks post-treatment), diversity did not decrease over the entire period despite four rounds of mass treatment. Furthermore, within-host genetic diversity was affected by host age, host sex, infection intensity and recent praziquantel treatment. Conclusions: Our findings suggest that praziquantel treatments have short-term impacts on these parasite populations but impacts were transient and no long-term reduction in genetic diversity was observed. High gene flow reduces the likelihood of local adaptation, so even though parasites surviving treatment were observed, these were likely to be diluted at the beginning of the Ugandan National Control Programme. Together, these results suggest that MDA in isolation may be insufficient to reduce schistosome populations in regions with high genetic diversity and gene flow

A rapid method for determining apparent diffusion coefficients in chalk and other consolidated porous media

The development of a method for the determination of the apparent diffusion coefficient, DA, for chloride in saturated Chalk cores is described. The method is rapid compared with other approaches, taking typically less than 24 h for a single determination. Cylindrical Chalk cores approximately 25 mm high by 25 mm in diameter, which are routinely used in porosity and permeability measurements and which had been pre-equilibrated with a 200 mg/L chloride solution, were sealed at both ends and attached to a slowly rotating spindle suspended in a reservoir. A chloride ion-selective electrode (ISE) connected to a data logger was used to record chloride diffusion out of the core. DA was estimated by analysing the change in chloride concentration in the reservoir with time. Diffusion coefficients were estimated for six Chalk samples from a range of Chalk lithologies. Sample porosities for these Chalks ranged from 32% to 48% and gas permeabilities from 0.3 to 8.2 × 10?9 m2. The DA was found to vary from 3.1 to 8.7 × 10?10 m2/s, a similar range to that observed by others. A bromide ISE was also used on one sample and found to give a similar DA to that obtained for chloride. This approach, which combines a rigorous mathematical model of diffusion with a relatively simple practical method, could easily be adapted for other ions and for other consolidated porous media.<br/