Predicting Medical Student Success on Licensure Exams

Many schools seek to predict performance on national exams required for medical school graduation using prematriculation and medical school performance data. The need for targeted intervention strategies for at-risk students has led much of this interest. Assumptions that preadmission data and high stakes in-house medical exams correlate strongly with national standardized exam performance needs to be examined. Looking at prematriculation data for predicting USMLE Step 1 performance, we found that MCAT exam totals and math-science GPA had the best prediction from a set of prematriculation values (adjusted R 2 = 11.7 %) for step 1. The addition of scores from the first medical school exam improved our predictive capabilities with a linear model to 27.9 %. As we added data to the model, we increased our predictive values as expected. However, it was not until we added data from year 2 exams that we started to get step 1 prediction values that exceeded 50 %. Stepwise addition of more exams in year two resulted in much higher predictive values but also led to the exclusion of many early variables. Therefore, our best step 1 predictive value of around 76.7 % consisted of three variables from a total of 37. These data suggest that the preadmission information is a relatively poor predictor of licensure exam performance and that including class exam scores allows for much more accurate determination of students who ultimately proved to be at risk for performance on their licensure exams. The continuous use of this data, as it becomes available, for assisting at-risk students is discussed (251)

Gravitational waves from pulsations of neutron stars described by realistic Equations of State

In this work we discuss the time-evolution of nonspherical perturbations of a nonrotating neutron star described by a realistic Equation of State (EOS). We analyze 10 different EOS for a large sample of neutron star models. Various kind of generic initial data are evolved and the corresponding gravitational wave signals are computed. We focus on the dynamical excitation of fluid and spacetime modes and extract the corresponding frequencies. We employ a constrained numerical algorithm based on standard finite differencing schemes which permits stable and long term evolutions. Our code provides accurate waveforms and allows to capture, via Fourier analysis of the energy spectra, the frequencies of the fluid modes with an accuracy comparable to that of frequency domain calculations. The results we present here are useful for provindig comparisons with simulations of nonlinear oscillations of (rotating) neutron star models as well as testbeds for 3D nonlinear codes.Comment: 17 pages, 9 figures. Small changes. Version published in Phys. Rev.

EC00-2540 Field Records for Restricted Use Pesticide Applications and Integrated Crop Management by Private Applicators

Private applicators must record their restricted use pesticide (RUP) applications, as required by the Food, Agriculture, Conservation and Trade (FACT) Act of 1990. The USDA Agricultural Marketing Service administers this activity. In Nebraska, RUP application records must be maintained for three years from the date of application. The certified pesticide applicator should retain these RUP records, but must be able to make them accessible for copying by authorized representatives. This booklet is a suggested guide for preliminary or final RUP application records

EC02-179 Managing Livestock Manure to Protect Environmental Quality

This book covers the land application part of manure management. With increasing regulations, the livestock producer needs to understand the scientific principles that affect manure transformations and how to use these principles to manage the manure for maximum fertilizer value with minimal environmental impact. Improved land application of manure is one part of the solution, but we suggest that the producer evaluate the quantity of nutrients arriving on the farm as feed, animals, and fertilizer compared to the total that is exported. Achieving a nutrient balance will reduce potential environmental hazards often associated with animal agriculture

Black Hole Spin Evolution

We consider a subset of the physical processes that determine the spin j = a/M of astrophysical black holes. These include: (1) Initial conditions. Recent models suggest that the collapse of supermassive stars are likely to produce black holes with j ~ 0.7. (2) Major mergers. The outcome of a nearly equal mass black hole-black hole merger is not yet known, but we review the current best guesses and analytic bounds. (3) Minor mergers. We recover the result of Blandford & Hughes that accretion of small companions with isotropically distributed orbital angular momenta results in spindown, with j ~ M^{-7/3}. (4) Accretion. We present new results from fully relativistic magnetohydrodynamic accretion simulations. These show that, at least for one sequence of flow models, spin equilibrium (dj/dt = 0) is reached for j ~ 0.9, far less than the canonical value 0.998 of Thorne that was derived in the absence of MHD effects. This equilibrium value may not apply to all accretion flows, particularly thin disks. Nevertheless, it opens the possibility that black holes that have grown primarily through accretion are not maximally rotating.Comment: 22 pp, 4 figures, accepted to Ap

Finding black holes in numerical spacetimes

We have constructed a numerical code that finds black hole event horizons in an axisymmetric rotating spacetime. The spacetime is specified numerically by giving metric coefficients on a spatial grid for a series of time slices. The code solves the geodesic equation for light rays emitted from a suitable sample of points in the evolving spacetime. The algorithm for finding the event horizon employs the apparent horizon, which can form much later than the event horizon, to distinguish between light rays that escape to infinity and light rays that are captured. Simple geometries can be diagnosed on a workstation; more complicated cases are computationally intensive. However, the code is easily parallelized and has been efficiently run on the IBM SP-1 parallel machine. We have illustrated the use of the event horizon code on two cases. One is the head-on collision of two black holes that form from the collapse of collisionless matter, coalescing to a single Schwarzschild black hole. The other is the collapse of a rotating toroid to form a Kerr black hole. In this case the horizon initially appears with a toroidal topology. This is the first known example of this phenomenon

MicroRNA-221/222 Confers Tamoxifen Resistance in Breast Cancer by Targeting p27\u3csup\u3eKip1\u3c/sup\u3e

We explored the role of microRNAs (miRNAs) in acquiring resistance to tamoxifen, a drug successfully used to treat women with estrogen receptor-positive breast cancer. miRNA microarray analysis of MCF-7 cell lines that are either sensitive (parental) or resistant (4-hydroxytamoxifen-resistant (OHTR)) to tamoxifen showed significant (50%) of seven miRNAs in OHT R cells compared with parental MCF-7 cells. Increased expression of three of the most promising up-regulated (miR-221, miR-222, and miR-181) and down-regulated (miR-21, miR-342, and miR-489) miRNAs was validated by real-time reverse transcription-PCR. The expression of miR-221 and miR-222 was also significantly (2-fold) elevated in HER2/neu-positive primary human breast cancer tissues that are known to be resistant to endocrine therapy compared with HER2/neu-negative tissue samples. Ectopic expression of miR-221/222 rendered the parental MCF-7 cells resistant to tamoxifen. The protein level of the cell cycle inhibitor p27Kip1, a known target of miR-221/222, was reduced by 50% in OHTR cells and by 28-50% in miR-221/222-overexpressing MCF-7 cells. Furthermore, overexpression of p27Kip1 in the resistant OHT R cells caused enhanced cell death when exposed to tamoxifen. This is the first study demonstrating a relationship between miR-221/222 expression and HER2/neu overexpression in primary breast tumors that are generally resistant to tamoxifen therapy. This finding also provides the rationale for the application of altered expression of specific miRNAs as a predictive tamoxifen-resistant breast cancer marker