480 research outputs found

    Ultrahigh Bandwidth Spin Noise Spectroscopy: Detection of Large g-Factor Fluctuations in Highly n-Doped GaAs

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    We advance all optical spin noise spectroscopy (SNS) in semiconductors to detection bandwidths of several hundred gigahertz by employing an ingenious scheme of pulse trains from ultrafast laser oscillators as an optical probe. The ultrafast SNS technique avoids the need for optical pumping and enables nearly perturbation free measurements of extremely short spin dephasing times. We employ the technique to highly n-doped bulk GaAs where magnetic field dependent measurements show unexpected large g-factor fluctuations. Calculations suggest that such large g-factor fluctuations do not necessarily result from extrinsic sample variations but are intrinsically present in every doped semiconductor due to the stochastic nature of the dopant distribution.Comment: 5 pages, 3 figure

    Cognitive Aid Use Improves Transition of Care by Graduating Medical Students During a Simulated Crisis

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    Background: Residents are expected to have transition of care (ToC) skills upon entering graduate medical education. It is unclear whether experience and training during medical school is adequate. Objective: The aim of the project was to assess: 1) graduating medical students\u27 ability to perform ToC in a crisis situation, and 2) whether using a cognitive aid improves the ToC quality. Methods: The authors developed simulation scenarios for rapid response teams and a cognitive aid to assist in the ToC during crisis situations. Graduating medical students were enrolled and randomly divided into teams of three students, randomly assigned into one of two groups: teams using a cognitive aid for ToC (CA), or not using a cognitive aid (nCA). In the scenario, teams respond to a deteriorating patient and then transfer care to the next provider after stabilization. Three faculty reviewed the recording to assess completeness of the ToC and the overall quality. A completeness score was expressed as a fraction of the maximum score. Statistical analysis was performed using a t-test and Mann-Whitney U test. Results: A total of 112 senior medical students participated: CA n=19, nCA n=17. The completeness score of the ToC and overall quality improved when using the cognitive aid (completeness score: CA 0.80±0.06 vs. nCA 0.52±0.07, p \u3c 0.01; ToC quality: CA 3.16±0.65 vs. nCA 1.92±0.56, p \u3c 0.01). Participants’ rating of knowledge and comfort with the ToC process increased after the simulation. Conclusion: The completeness of information transfer during the ToC process by graduating medical students improved by using a cognitive aid in a simulated patient crisis

    Nutrient Return from Plant Litter and Cattle Excretion Grazing on N-Fertilized Grass or Grass-Legume Pastures in North Florida

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    Nutrient recycling via plant litter and livestock excreta is an important ecosystem service provided by grasslands. This study determined nutrient return via these pathways in three grazing systems. The experiment was conducted from May to October (2016 and 2017) and treatments were: 1) Nitrogen fertilized bahiagrass (Paspalum notatum Flügge) pastures (112 kg N ha-1) during the warm-season, overseeded with a mixture (56 kg ha-1 of each) of ‘FL 401’ cereal rye (Secale cereale, L.) and ‘RAM’ oat (Avena sativa, L.) during the cool-season (BGN); 2) Ecoturf Rhizoma peanut (Arachis glabrata Benth.)/bahiagrass pastures during the warm-season, overseeded with similar rye/oat mixture fertilized with 34 kg N ha-1 plus a mixture of clovers (Trifolium incarnatum L., T. pretense L., and T. nigrescens L.) during the cool-season (BGRP); 3) unfertilized bahiagrass pastures during the warm-season, overseeded with similar rye/oat grass/clover mixture + 34 kg N ha-1 during the cool-season (BG). Litter mass was evaluated every 5wk. Litter decomposition was evaluated with incubation periods of 0, 2, 4, 8, 16, 32, 64, 128, and 256 days. Urine and fecal samples were collected for N concentration analysis. There was a net return of 47 kg N ha-1 season-1 via litter in all three systems without differing among them. In addition, litter decomposition rates were not different in the three systems. Conversely, N returned via excreta (urine and feces) was greater (63, 27, and 51 kg N ha-1 season-1) than that returned via litter (58.6, 41.6, and 41.2 kg ha-1 season-1). When assessing the proportions of N returning to the system via litter or excreta, no differences were observed among treatments, and on average 65.1 % of the N returned via excreta vs. 34.9 % returning via litter. The introduction of legumes could reduce the inputs from N fertilizers in grazing systems and keep the productivity similar because of more efficient N cycling

    A Smartphone-based Decision Support Tool Improves Test Performance Concerning Application of the Guidelines for Managing Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy

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    BACKGROUND: The American Society of Regional Anesthesia and Pain Medicine (ASRA) consensus statement on regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy is the standard for evaluation and management of these patients. The authors hypothesized that an electronic decision support tool (eDST) would improve test performance compared with native physician behavior concerning the application of this guideline. METHODS: Anesthesiology trainees and faculty at 8 institutions participated in a prospective, randomized trial in which they completed a 20-question test involving clinical scenarios related to the ASRA guidelines. The eDST group completed the test using an iOS app programmed to contain decision logic and content of the ASRA guidelines. The control group completed the test by using any resource in addition to the app. A generalized linear mixed-effects model was used to examine the effect of the intervention. RESULTS: After obtaining institutional review board's approval and informed consent, 259 participants were enrolled and randomized (eDST = 122; control = 137). The mean score was 92.4 ± 6.6% in the eDST group and 68.0 ± 15.8% in the control group (P < 0.001). eDST use increased the odds of selecting correct answers (7.8; 95% CI, 5.7 to 10.7). Most control group participants (63%) used some cognitive aid during the test, and they scored higher than those who tested from memory alone (76 ± 15% vs. 57 ± 18%, P < 0.001). There was no difference in time to completion of the test (P = 0.15) and no effect of training level (P = 0.56). CONCLUSIONS: eDST use improved application of the ASRA guidelines compared with the native clinician behavior in a testing environment

    Prevention of “Humanized” Diabetogenic CD8 T-Cell Responses in HLA-Transgenic NOD Mice by a Multipeptide Coupled-Cell Approach

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    OBJECTIVE: Type 1 diabetes can be inhibited in standard NOD mice by autoantigen-specific immunotherapy targeting pathogenic CD8+ T-cells. NOD.beta2m(null).HHD mice expressing human HLA-A2.1 but lacking murine major histocompatibility complex class I molecules develop diabetes characterized by CD8 T-cells recognizing certain autoantigenic peptides also targeted in human patients. These include peptides derived from the pancreatic beta-cell proteins insulin (INS1/2 A(2-10) and INS1 B(5-14)) and islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP(265-273) and IGRP(228-236)). Hence, NOD.beta2m(null).HHD mice represent a model system for developing potentially clinically translatable interventions for suppressing diabetogenic HLA-A2.1-restricted T-cell responses. RESEARCH DESIGN AND METHODS: Starting at 4-6 weeks of age, NOD.beta2m(null).HHD female mice were injected intravenously with syngeneic splenocytes to which various admixtures of the four above-mentioned peptides were bound by the cross-linking agent ethylene carbodiimide (ECDI). RESULTS: Treatment with such cells bearing the complete cocktail of INS and IGRP epitopes (designated INS/IGRP-SPs) significantly inhibited diabetes development in NOD.beta2m(null).HHD recipients compared with controls receiving splenocytes coupled with an irrelevant HLA-A2.1-restricted Flu16 peptide. Subsequent analyses found syngeneic splenocytes bearing the combination of the two ECDI-coupled IGRPs but not INS peptides (IGRP-SPs or INS-SPs) effectively inhibited diabetes development in NOD.beta2m(null).HHD mice. This result was supported by enzyme-linked immunospot (ELISPOT) analyses indicating combined INS/IGRP-SPs diminished HLA-A2.1-restricted IGRP but not INS autoreactive CD8+ T-cell responses in NOD.beta2m(null).HHD mice. CONCLUSIONS: These data support the potential of a cell therapy approach targeting HLA-A2.1-restricted IGRP autoreactive CD8 T-cells as a diabetes intervention approach in appropriate human patients
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