2,007 research outputs found
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The evolving maintenance of certification process: update on the financial status of the medical boards
Medical board organizations have accumulated large asset balances, in part due to the monetization of physician board recertification, as well as capital gains in positive investment conditions. Physicians across the country have raised concerns regarding the effectiveness and efficiency of existing recertification processes, to which the American Board of Medical Specialties and independent accreditation boards have responded with newly instituted changes. The present article analyzes the publicly available F990 tax forms of the medical boards in an effort to provide data to the ongoing debate. Although some boards have begun to mobilize assets in recent years, many continue to accumulate wealth. It remains to be seen whether the new recertification programs will bring about change or perpetuate organizational wealth
Synthesis of Colloidal Mn2+:ZnO Quantum Dots and High-TC Ferromagnetic Nanocrystalline Thin Films
We report the synthesis of colloidal Mn2+-doped ZnO (Mn2+:ZnO) quantum dots
and the preparation of room-temperature ferromagnetic nanocrystalline thin
films. Mn2+:ZnO nanocrystals were prepared by a hydrolysis and condensation
reaction in DMSO under atmospheric conditions. Synthesis was monitored by
electronic absorption and electron paramagnetic resonance (EPR) spectroscopies.
Zn(OAc)2 was found to strongly inhibit oxidation of Mn2+ by O2, allowing the
synthesis of Mn2+:ZnO to be performed aerobically. Mn2+ ions were removed from
the surfaces of as-prepared nanocrystals using dodecylamine to yield
high-quality internally doped Mn2+:ZnO colloids of nearly spherical shape and
uniform diameter (6.1 +/- 0.7 nm). Simulations of the highly resolved X- and
Q-band nanocrystal EPR spectra, combined with quantitative analysis of magnetic
susceptibilities, confirmed that the manganese is substitutionally incorporated
into the ZnO nanocrystals as Mn2+ with very homogeneous speciation, differing
from bulk Mn2+:ZnO only in the magnitude of D-strain. Robust ferromagnetism was
observed in spin-coated thin films of the nanocrystals, with 300 K saturation
moments as large as 1.35 Bohr magneton/Mn2+ and TC > 350 K. A distinct
ferromagnetic resonance signal was observed in the EPR spectra of the
ferromagnetic films. The occurrence of ferromagnetism in Mn2+:ZnO and its
dependence on synthetic variables are discussed in the context of these and
previous theoretical and experimental results.Comment: To be published in the Journal of the American Chemical Society Web
on July 14, 2004 (http://dx.doi.org/10.1021/ja048427j
Ancient Jewish Historians and the German Reich. Seven Studies
Apart from an opening survey of modern study of ancient Jewish history, which emphasizes the foundational role of German-Jewish scholars, the studies united in this volume apply philological methods to the writings of four of them: Heinrich Graetz, Isaak Heinemann, Elias Bickerman(n), and Abraham Schalit. In each case, it is argued that some seemingly trivial anomaly or infelicity, in a publication about such ancient characters as Antiochus Epiphanes, Herod, and Josephus, points to the way in which the historian constructed, and revised, his understanding of the Jewsâ situation under Greeks or Romans in light of his perception of the Jewsâ situation under the Second or Third Reich. The collection also includes a study that focuses on a Jewish medievalist, Philipp JaffĂ©, and unravels the indirect but inexorable process that led from a scholarly feud about the editing of medieval Latin texts, in the 1860s, to the âBerlin Antisemitism Disputeâ (Berliner Antisemitismusstreit) of 1879â1881, which is commonly viewed as the opening act of modern German antisemitism
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Is Depression After an Acute Coronary Syndrome Simply a Marker of Known Prognostic Factors for Mortality?
Objective: Controversy remains over whether the association between depression and mortality in patients with acute coronary syndrome (ACS) is confounded by incomplete adjustment for measures of known prognostic markers. We assessed a) whether depression was associated with the most comprehensive empirically derived index of clinical mortality predictors: the Global Registry of Acute Coronary Events (GRACE) risk score for predicting 6-month mortality after discharge for ACS; and b) whether depression remained an independent predictor of all-cause mortality after adjustment for the GRACE score and left ventricular dysfunction.
Methods: We surveyed prospectively 457 patients with ACS (aged 25â92 years; 41% women, 13% black, and 11% Hispanic), hospitalized between May 2003 and June 2005. Depressive symptoms were assessed with the Beck Depression Inventory (BDI) and diagnosis of major depressive disorder (MDD) was made by a structured psychiatric interview, within 1 week of hospitalization.
Results: Despite differences in individual components of the GRACE score between depressed and nondepressed participants, neither depression measure was associated with overall GRACE score. For participants with MDD, the mean ± standard deviation GRACE score was 84 ± 33, compared with 92 ± 31 for those without MDD (p = .09). Using Cox proportional hazards regression analysis, MDD and depressive symptom severity each predicted mortality after controlling for GRACE score and left ventricular dysfunction (adjusted hazard ratio for MDD = 2.51; 95% Confidence Interval = 1.45â4.37).
Conclusion: Depression is not simply a marker of clinical indicators that predict all-cause mortality after ACS. This strengthens the assertion that there is something unique in the association between depression and post-ACS prognosis, independent of known prognostic markers
Dealing with Uncertainties in Asteroid Deflection Demonstration Missions: NEOTwIST
Deflection missions to near-Earth asteroids will encounter non-negligible
uncertainties in the physical and orbital parameters of the target object. In
order to reliably assess future impact threat mitigation operations such
uncertainties have to be quantified and incorporated into the mission design.
The implementation of deflection demonstration missions offers the great
opportunity to test our current understanding of deflection relevant
uncertainties and their consequences, e.g., regarding kinetic impacts on
asteroid surfaces. In this contribution, we discuss the role of uncertainties
in the NEOTwIST asteroid deflection demonstration concept, a low-cost kinetic
impactor design elaborated in the framework of the NEOShield project. The aim
of NEOTwIST is to change the spin state of a known and well characterized
near-Earth object, in this case the asteroid (25143) Itokawa. Fast events such
as the production of the impact crater and ejecta are studied via cube-sat
chasers and a flyby vehicle. Long term changes, for instance, in the asteroid's
spin and orbit, can be assessed using ground based observations. We find that
such a mission can indeed provide valuable constraints on mitigation relevant
parameters. Furthermore, the here proposed kinetic impact scenarios can be
implemented within the next two decades without threatening Earth's safety.Comment: Accepted for publication in the proceedings of the IAUS 318 -
Asteroids: New Observations, New Models, held at the IAU General Assembly in
Honolulu, Hawaii, USA 201
The Fabrication, Testing and Simulation of Germanium Thermophotovoltaic Cells
This is the final report on NRL Contract N00173-79-C-0362. The purpose of this investigation was to fabricate germanium photovoltaic cells and to examine the feasibility of using them in a thermophotovoltaic system for the generation of electrical power in space. The energy source was to be solar. Systems aspects of the collection of solar energy and rejection of waste heat were not a part of this study. The strategy employed in this investigation was the following. 1. Fabricate germanium photodiodes. 2. Carefully characterize these photodiodes. 3. Simulate the performance of these photodiodes using a detailed numerical model of the cell and the illuminating spectra. 4. Use this simulation program to project the potential performance of germanium photodiodes in a thermophotovoltaic system under various assumptions about future improvements in diode performance and under various thermophotovoltaic spectral condition
Comparison of transcranial electric motor and somatosensory evoked potential monitoring during cervical spine surgery.
BACKGROUND: There has been little enthusiasm for somatosensory evoked potential monitoring in cervical spine surgery as a result, in part, of the increased risk of motor tract injury at this level, to which somatosensory monitoring may be insensitive. Transcranial electric motor evoked potential monitoring allows assessment of the motor tracts; therefore, we compared transcranial electric motor evoked potential and somatosensory evoked potential monitoring during cervical spine surgery to determine the temporal relationship between the changes in the potentials demonstrated by each type of monitoring and neurological sequelae and to identify patient-related and surgical factors associated with intraoperative neurophysiological changes.
METHODS: Somatosensory evoked potential and transcranial electric motor evoked potential data recorded for 427 patients undergoing anterior or posterior cervical spine surgery between January 1999 and March 2001 were analyzed. All patients who showed substantial (at least 60%) or complete unilateral or bilateral amplitude loss, for at least ten minutes, during the transcranial electric motor evoked potential and/or somatosensory evoked potential monitoring were identified.
RESULTS: Twelve of the 427 patients demonstrated substantial or complete loss of amplitude of the transcranial electric motor evoked potentials. Ten of those patients had complete reversal of the loss following prompt intraoperative intervention, whereas two awoke with a new motor deficit. Somatosensory evoked potential monitoring failed to identify any change in one of the two patients, and the change in the somatosensory evoked potentials lagged behind the change in the transcranial electric motor evoked potentials by thirty-three minutes in the other. No patient showed loss of amplitude of the somatosensory evoked potentials in the absence of changes in the transcranial electric motor evoked potentials. Transcranial electric motor evoked potential monitoring was 100% sensitive and 100% specific, whereas somatosensory evoked potential monitoring was only 25% sensitive; it was, however, 100% specific.
CONCLUSIONS: Transcranial electric motor evoked potential monitoring appears to be superior to conventional somatosensory evoked potential monitoring for identifying evolving motor tract injury during cervical spine surgery. Surgeons should strongly consider using this modality when operating on patients with cervical spondylotic myelopathy in general and on those with ossification of the posterior longitudinal ligament in particular
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