Influence of Assigned Reading on Senior Medical Student Clinical Performance

Objective: This Institutional Review Board-approved, prospective, observational study compared the clinical performance of senior medical students in an emergency medicine (EM) clerkship using a clinical behavioral evaluation tool in which one group had mandatory, topic specific readings and the other did not.Methods: The study took place in an urban, tertiary referral center emergency department treating 43,000 patients annually and supporting medical student clerkships and an EM residency. The grades of two groups of senior medical students participating in an elective EM clerkship were compared. Those students during the 2002-2004 academic years were not assigned mandatory, topic-specific reading for the clerkship, while those during the 2004-2007 academic years were. The groups were compared on baseline demographic information, prior academic performance, and EM clerkship grade distributions using appropriate statistical techniques, including multinomial logistic regression, chi-square tests, and Fisher’s Exact tests.Results: The control and experimental groups each had 83 subjects and were similar in baseline characteristics, except for the control group performing better than the experimental group during the basic science training of medical school (years 1-2; p=0.01). The experimental group had statistically significant more members in the EM Interest Group (EMIG; p=0.0001) and more members who went on to match in an EM residency (p=0.0007). The difference in grade distributions between the control group and experimental group was not statistically significant (p=0.40). Of note, those student members of the EMIG (p=0.0005) and those later matching to an emergency medicine residency (p<0.0001) were more likely to earn a grade of “honors” for the clerkship.Conclusion: The addition of uniform, topic-specific reading assignments to an EM senior medical student curriculum does not improve the overall clinical performance of those students as measured using a clinical behavioral evaluation tool.[WestJEM. 2009;10:23-29.

Self-Reported Emergency Medicine Residency Applicant Attitudes Towards a Procedural Cadaver Laboratory Curriculum

Objective: Residency applicants consider a variety of factors when ranking emergency medicine (EM) programs for their NRMP match list. A human cadaver emergency procedure lab curriculum is uncommon. We hypothesized that the presence this curriculum would positively impact the ranking of an EM residency program.Methods: The EM residency at Nebraska Medical Center is an urban, university-based program with a PGY I-III format. Residency applicants during the interview for a position in the PGY I class of 2006 were surveyed by three weekly electronic mailings. The survey was distributed in March 2006 after the final NRMP match results were released. The survey explored learner preferences and methodological commonality of models of emergency procedural training, as well as the impact of a procedural cadaver lab curriculum on residency ranking. ANOVA of ranks was used to compare responses to ranking questions.Results: Of the 73 potential subjects, 54 (74%) completed the survey. Respondents ranked methods of procedural instruction from 1 (most preferred or most common technique) to 4 (least preferred or least common technique). Response averages and 95% confidence intervals for the preferred means of learning a new procedure are as follows: textbook (3.69; 3.51-3.87), mannequin (2.83; 2.64-3.02), human cadaver (1.93; 1.72-2.14), and living patient (1.56; 1.33-1.79). Response averages for the commonality of means used to teach a new procedure are as follows: human cadaver (3.63; 3.46-3.80), mannequin (2.70; 2.50-2.90), living patient (2.09; 1.85-2.33), and textbook (1.57; 1.32-1.82). When asked if the University of Nebraska Medical Center residency ranked higher in the individual’s match list because of its procedural cadaver lab, 14.8% strongly disagreed, 14.8% disagreed, 40.7% were neutral, 14.8% agreed, and 14.8% strongly agreed.Conclusion: We conclude that, although cadaveric procedural training is viewed by senior medical student learners as a desirable means of learning a procedure, its use is uncommon during medical school, and its presence as part of a residency curriculum does not influence ranking of the residency program.[WestJEM. 2008;9:141-145.

Electron Transfer Precedes ATP Hydrolysis during Nitrogenase Catalysis

The biological reduction of N2 to NH3 catalyzed by Mo-dependent nitrogenase requires at least eight rounds of a complex cycle of events associated with ATP-driven electron transfer (ET) from the Fe protein to the catalytic MoFe protein, with each ET coupled to the hydrolysis of two ATP molecules. Although steps within this cycle have been studied for decades, the nature of the coupling between ATP hydrolysis and ET, in particular the order of ET and ATP hydrolysis, has been elusive. Here, we have measured first-order rate constants for each key step in the reaction sequence, including direct measurement of the ATP hydrolysis rate constant: kATP = 70 s−1, 25 °C. Comparison of the rate constants establishes that the reaction sequence involves four sequential steps: (i) conformationally gated ET (kET = 140 s−1, 25 °C), (ii) ATP hydrolysis (kATP = 70 s−1, 25 °C), (iii) Phosphate release (kPi = 16 s−1, 25 °C), and (iv) Fe protein dissociation from the MoFe protein (kdiss = 6 s−1, 25 °C). These findings allow completion of the thermodynamic cycle undergone by the Fe protein, showing that the energy of ATP binding and protein–protein association drive ET, with subsequent ATP hydrolysis and Pi release causing dissociation of the complex between the Feox(ADP)2 protein and the reduced MoFe protein

Metroplex Optimization Model Expansion and Analysis: The Airline Fleet, Route, and Schedule Optimization Model (AFRS-OM)

This report describes the Airline Fleet, Route, and Schedule Optimization Model (AFRS-OM) that is designed to provide insights into airline decision-making with regards to markets served, schedule of flights on these markets, the type of aircraft assigned to each scheduled flight, load factors, airfares, and airline profits. The main inputs to the model are hedged fuel prices, airport capacity limits, and candidate markets. Embedded in the model are aircraft performance and associated cost factors, and willingness-to-pay (i.e. demand vs. airfare curves). Case studies demonstrate the application of the model for analysis of the effects of increased capacity and changes in operating costs (e.g. fuel prices). Although there are differences between airports (due to differences in the magnitude of travel demand and sensitivity to airfare), the system is more sensitive to changes in fuel prices than capacity. Further, the benefits of modernization in the form of increased capacity could be undermined by increases in hedged fuel price

System and Method for Generating Psuedo-Noise Sequences

Disclosed is a method for generating psuedo-noise (PN) sequences utilizing a system comprised of a quantizer, and N directly quantized output/input map containing chaotic map cells, each in functional combination with combiner means and an m-bit shift register

Optimizing Air Transportation Service to Metroplex Airports

The air transportation system is a significant driver of the U.S. economy, providing safe, affordable, and rapid transportation. During the past three decades airspace and airport capacity has not grown in step with demand for air transportation; the failure to increase capacity at the same rate as the growth in demand results in unreliable service and systemic delay. This report describes the results of an analysis of airline strategic decision-making that affects geographic access, economic access, and airline finances, extending the analysis of these factors using historic data (from Part 1 of the report). The Airline Schedule Optimization Model (ASOM) was used to evaluate how exogenous factors (passenger demand, airline operating costs, and airport capacity limits) affect geographic access (markets-served, scheduled flights, aircraft size), economic access (airfares), airline finances (profit), and air transportation efficiency (aircraft size). This analysis captures the impact of the implementation of airport capacity limits, as well as the effect of increased hedged fuel prices, which serve as a proxy for increased costs per flight that might occur if auctions or congestion pricing are imposed; also incorporated are demand elasticity curves based on historical data that provide information about how passenger demand is affected by airfare changes

Negative Cooperativity in the Nitrogenase Fe Protein Electron Delivery Cycle

Nitrogenase catalyzes the ATP-dependent reduction of dinitrogen (N2) to two ammonia (NH3) molecules through the participation of its two protein components, the MoFe and Fe proteins. Electron transfer (ET) from the Fe protein to the catalytic MoFe protein involves a series of synchronized events requiring the transient association of one Fe protein with each αβ half of the α2β2 MoFe protein. This process is referred to as the Fe protein cycle and includes binding of two ATP to an Fe protein, association of an Fe protein with the MoFe protein, ET from the Fe protein to the MoFe protein, hydrolysis of the two ATP to two ADP and two Pi for each ET, Pi release, and dissociation of oxidized Fe protein-(ADP)2 from the MoFe protein. Because the MoFe protein tetramer has two separate αβ active units, it participates in two distinct Fe protein cycles. Quantitative kinetic measurements of ET, ATP hydrolysis, and Pi release during the presteady-state phase of electron delivery demonstrate that the two halves of the ternary complex between the MoFe protein and two reduced Fe protein-(ATP)2 do not undergo the Fe protein cycle independently. Instead, the data are globally fit with a two-branch negative-cooperativity kinetic model in which ET in one-half of the complex partially suppresses this process in the other. A possible mechanism for communication between the two halves of the nitrogenase complex is suggested by normal-mode calculations showing correlated and anticorrelated motions between the two halves