Why Use Multiple Choice Questions with Excess Information?

The examinations administered by accounting instructors, professional certification examiners, textbook writers, and preparatory accounting software all routinely include multiple-choice (MC) questions with excess (yet related) information. Despite their widespread use, little is known about how MC questions with excess information (hereafter MCE questions) affect student test performance. Based on an empirical analysis of the tests of 374 students in two introductory accounting classes at a single university, we found that average performance was lower on MCE questions than non-MCE questions, but was sensitive to the overall difficulty of the tested concept. We also found no significant difference in the power of the two question types to discriminate—both types appeared equally competent in differentiating between low- and high-performing students. Although accounting professors may wish to use MC questions with excess information for a number of other reasons, we found that MCE questions, as used in the present setting, do not appear to better discriminate student understanding relative to non-MCE questions

QT-RR HYSTERESIS IS CAUSED BY DIFFERENTIAL AUTONOMIC STATES DURING EXERCISE AND RECOVERY

QT-RR hysteresis is characterized by longer QT intervals at a given RR interval while heart rates are increasing during exercise and shorter QT intervals at the same RR interval while heart rates are decreasing during recovery. It has been attributed to a lagging QT response to different directional changes in RR interval during exercise and recovery. Twenty control subjects (8 males, age 51 ± 6 yr), 16 subjects with type 2 diabetes (12 males, age 56 ± 8 yr), 71 subjects with coronary artery disease (CAD) and preserved left ventricular ejection fraction (LVEF) (≥50%) (51 males, age 59 ± 12 yr), and 17 CAD subjects with depressed LVEF (<50%) (13 males, age 57 ± 10 yr) underwent two 16-min exercise tests followed by recovery. In session 2, parasympathetic blockade with atropine (0.04 mg/kg) was achieved at end exercise. QT-RR hysteresis was quantified as: 1) the area bounded by the QT-RR relationships for exercise and recovery in the range of the minimum RR interval at peak exercise to the minimum RR interval + 100 ms and 2) the difference in QT interval duration between exercise and recovery at the minimum RR interval achieved during peak exercise plus 50 ms (ΔQT). The effect of parasympathetic blockade was assessed by substituting the QT-RR relationship after parasympathetic blockade. QT-RR hysteresis was positive in all groups at baseline and reversed by parasympathetic blockade (P < 0.01). We conclude that QT-RR hysteresis is not caused by different directional changes in RR interval during exercise and recovery. Instead, it is predominantly mediated by differential autonomic nervous system effects as the heart rate increases during exercise vs. as it decreases during recovery

Population pharmacokinetics of fluconazole in critically ill patients receiving continuous venovenous hemodiafiltration - using Monte Carlo Simulations to predict doses for specified pharmacodynamic targets

Fluconazole is a widely used antifungal agent that is extensively reabsorbed in patients with normal renal function. However, its reabsorption can be compromised in patients with acute kidney injury, thereby leading to altered fluconazole clearance and total systemic exposure. Here, we explore the pharmacokinetics of fluconazole in 10 critically ill anuric patients receiving continuous venovenous hemodiafiltration (CVVHDF). We performed Monte Carlo simulations to optimize dosing to appropriate pharmacodynamic endpoints for this population. Pharmacokinetic profiles of initial and steady-state doses of 200 mg intravenous fluconazole twice daily were obtained from plasma and CVVHDF effluent. Nonlinear mixed-effects modeling (NONMEM) was used for data analysis and to perform Monte Carlo simulations. For each dosing regimen, the free drug area under the concentration-time curve (fAUC)/MIC ratio was calculated. The percentage of patients achieving an AUC/MIC ratio greater than 25 was then compared for a range of MIC values. A two-compartment model adequately described the disposition of fluconazole in plasma. The estimate for total fluconazole clearance was 2.67 liters/h and was notably 2.3 times faster than previously reported in healthy volunteers. Of this, fluconazole clearance by the CVVHDF route (CL(CVVHDF)) represented 62% of its total systemic clearance. Furthermore, the predicted efficiency of CL(CVVHDF) decreased to 36.8% when filters were in use >48 h. Monte Carlo simulations demonstrated that a dose of 400 mg twice daily maximizes empirical treatment against fungal organisms with MIC up to 16 mg/liter. This is the first study we are aware of that uses Monte Carlo simulations to inform dosing requirements in patients where tubular reabsorption of fluconazole is probably nonexistent

Is Your C-Suite Risk Literate?

Managing risk effectively is essential for business success, and thus understanding risk is vital for business executives. Effective risk management increases firm value, whereas poor risk management will damage shareholder wealth. In this article, we examine the risk literacy of business executives and find significant variation among the leaders we sample. Our findings suggest that business executives would be well served to evaluate their own risk literacy, and remediate, if necessary; to work to increase risk literacy in the company’s employees; and to include risk literacy as an important and routine part of the firm’s overall culture. Because the importance of risk literacy increases with business complexity, we believe that risk literacy will only become more important in the future

Detection of Cardiovascular Autonomic Neuropathy Using Exercise Testing in Patients with Type 2 Diabetes Mellitus

This study investigated autonomic nervous system function in subjects with diabetes during exercise and recovery. Eighteen type 2 diabetics (age 55±2years) and twenty healthy controls (age 51±1years) underwent two 16-min bicycle submaximal ECG stress tests followed by 45min of recovery. During session #2, atropine (0.04mg/kg) was administered at peak exercise, and the final two minutes of exercise and entire recovery occurred under parasympathetic blockade. Plasma catecholamines were measured throughout. Parasympathetic effect was defined as the difference between a measured parameter at baseline and after parasympathetic blockade. The parasympathetic effect on the RR interval was blunted (P=.004) in diabetic subjects during recovery. Parasympathetic effect on QT–RR slope during early recovery was diminished in the diabetes group (diabetes 0.13±0.02, control 0.21±0.02, P=.03). Subjects with diabetes had a lower heart rate recovery at 1min (diabetes 18.5±1.9bpm, control 27.6±1.5bpm, P<.001). In subjects with well-controlled type 2 diabetes, even with minimal evidence of CAN using current methodology, altered cardiac autonomic balance is present and can be detected through an exercise-based assessment for CAN. The early post-exercise recovery period in diabetes was characterized by enhanced sympathoexcitation, diminished parasympathetic reactivation and delay in heart rate recovery

Recovery of Heart Rate Variability and Ventricular Repolarization Indices Following Exercise

BACKGROUND: There is a heightened risk of sudden cardiac death related to exercise and the post-exercise recovery period, but the precise mechanism is unknown. We have demonstrated that sympathoexcitation persists for ≥45 minutes after exercise in normals and subjects with coronary artery disease (CAD). The purpose of this study is to determine whether this persistent sympathoexcitation is associated with persistent heart rate variability (HRV) and ventricular repolarization changes in the post-exercise recovery period. METHODS AND RESULTS: Twenty control subjects (age 50.7±1.4 years), 68 subjects (age 58.2±1.5 years) with CAD and preserved left ventricular ejection fraction (LVEF), and 18 subjects (age 57.6±2.4 years) with CAD and depressed LVEF underwent a 16-minute submaximal bicycle exercise protocol with continuous ECG monitoring. QT and RR intervals were measured in recovery to calculate the time dependent corrected QT intervals (QTc), the QT-RR relationship, and HRV. QTc was dependent on the choice of rate correction formula. There were no differences in QT-RR slopes among the 3 groups in early recovery. HRV recovered quickly in controls, more slowly in those with CAD-preserved LVEF, and to a lesser extent in those with CAD-depressed LVEF. CONCLUSION: Despite persistent sympathoexcitation for the 45 minute recovery period, ventricular repolarization changes do not persist for that long and HRV changes differ by group. Further understanding of the dynamic changes in cardiac parameters after exercise are needed to explore the mechanism of increased sudden cardiac death risk at this time

Persistent Sympathoexcitation Long After Submaximal Exercise in Subjects with and without Coronary Artery Disease

There is an increased risk of cardiac events after exercise, which may, in part, be mediated by the sympathoexcitation that accompanies exercise. The duration and extent of this sympathoexcitation following moderate exercise is unknown, particularly in those with coronary artery disease (CAD). Twenty control subjects (mean age, 51 years) and 89 subjects with CAD (mean age, 58 years) underwent two 16-min bicycle exercise sessions followed by 30-45 min of recovery. Session 1 was performed under physiological conditions to peak workloads of 50-100 W. In session 2, parasympathetic blockade with atropine (0.04 mg/kg) was achieved at end exercise at the same workload as session 1. RR interval was continually recorded, and plasma catecholamines were measured at rest and selected times during exercise and recovery. Parasympathetic effect, measured as the difference in RR interval with and without atropine, did not differ between controls and CAD subjects in recovery. At 30 and 45 min of recovery, RR intervals were 12% and 9%, respectively, shorter than at rest. At 30 and 45 min of recovery, plasma norepinephrine levels were 15% and 12%, respectively, higher than at rest. A brief period of moderate exercise is associated with a prolonged period of sympathoexcitation extending \u3e45 min into recovery and is quantitatively similar among control subjects and subjects with CAD, with or without left ventricular dysfunction. Parasympathetic reactivation occurs early after exercise and is also surprisingly quantitatively similar in controls and subjects with CAD. The role of these autonomic changes in precipitating cardiac events requires further evaluation