A proposed experiment to demonstrate optical stochastic cooling (OSC) in the Cornell Electron Storage Ring (CESR) based on an arc-bypass design is presented. This arc bypass provides significantly ...longer optical delay than the dog-leg style chicane, opening up the possibility of a multipass or staged optical amplifier that can achieve the gains required for effective cooling of hadron or heavy ions. Beyond introducing the arc bypass, in this paper we study the stability requirements for the dipoles comprising it and investigate the use of an optical feedback system to relax the dipole and light-path stability tolerances.
We report the design and performance of a time-resolved electron diffraction apparatus capable of producing intense bunches with simultaneously single digit micrometer probe size, long coherence ...length, and 200 fs rms time resolution. We measure the 5d (peak) beam brightness at the sample location in micro-diffraction mode to be
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2. To generate high brightness electron bunches, the system employs high efficiency, low emittance semiconductor photocathodes driven with a wavelength near the photoemission threshold at a repetition rate up to 250 kHz. We characterize spatial, temporal, and reciprocal space resolution of the apparatus. We perform proof-of-principle measurements of ultrafast heating in single crystal Au samples and compare experimental results with simulations that account for the effects of multiple scattering.
In preparation for a demonstration of optical stochastic cooling in Cornell Electron Storage Ring, we have developed a particle tracking simulation to study the relevant beam dynamics. Optical ...radiation emitted in the pickup undulator gives a momentum kick to that same particle in the kicker undulator. The optics of the electron bypass from pickup to kicker couples betatron amplitude and momentum offset to path length so that the momentum kick reduces emittance and momentum spread. Nearby electrons contribute an incoherent noise. Layout of the bypass line is presented that accommodates optics with a range of transverse and longitudinal cooling parameters. The simulation is used to determine cooling rates and their dependence on bunch and lattice parameters for bypass optics with distinct emittance and momentum acceptance.
Electronic health record (EHR) data have emerged as an important resource for population health and clinical research. There have been significant efforts to leverage EHR data for research; however, ...given data security concerns and the complexity of the data, EHR data are frequently difficult to access and use for clinical studies. We describe the development of a Clinical Research Datamart (CRDM) that was developed to provide well-curated and easily accessible EHR data to Duke University investigators.
The CRDM was designed to (1) contain most of the patient-level data elements needed for research studies; (2) be directly accessible by individuals conducting statistical analyses (including Biostatistics, Epidemiology, and Research Design (BERD) core members); (3) be queried via a code-based system to promote reproducibility and consistency across studies; and (4) utilize a secure protected analytic workspace in which sensitive EHR data can be stored and analyzed. The CRDM utilizes data transformed for the PCORnet data network, and was augmented with additional data tables containing site-specific data elements to provide additional contextual information.
We provide descriptions of ideal use cases and discuss dissemination and evaluation methods, including future work to expand the user base and track the use and impact of this data resource.
The CRDM utilizes resources developed as part of the Clinical and Translational Science Awards (CTSAs) program and could be replicated by other institutions with CTSAs.
This paper details the development of a single-shot diagnostic technique for the 4D average and core phase space densities of low-charge, high-brightness electron beams, based on the analysis of ...shadow point-projection images of metal grids. This technique is similar to the standard pepper pot method, although it allows much greater transmission of the beam and therefore is more suitable for low-charge electron beams. Transverse coupling terms are included in the analysis, allowing the complete 4D transverse beam matrix to be reconstructed. The 4D beam phase space information is extremely important for the characterization of nonround beams. An analysis of the resolution limits and experimental benchmarking of the technique with pepper-pot emittance measurements are presented.
In this paper, we study by numerical simulations a time-resolved MeV electron scattering mode where two consecutive electron pulses are used to capture the evolution of a material sample on 10 ps ...time scales. The two electron pulses are generated by illuminating a photocathode in a radiofrequency photogun by two short laser pulses with adjustable delay. A streak camera/deflecting cavity is used after the sample to project the two electron bunches on two well separated regions of the detector screen. By using sufficiently short pulses, the 2D spatial information from each snapshot can be preserved. This “double-shot” technique enables the efficient capture of irreversible dynamics in both diffraction and imaging modes. In this work, we demonstrate both modes in start-to-end simulations of the UCLA Pegasus MeV microscope column.
Ultra-flat, ultra-thin alkali antimonide photocathodes with high crystallinity can exhibit high quantum efficiency and low mean transverse energy of outgoing electrons, which are essential ...requirements for a variety of applications for photocathode materials. Here, we investigate the growth of Cs3Sb on graphene-coated 4H–SiC (Gr/4H–SiC), 3C–SiC, and Si3N4 substrates. Sb is deposited using pulsed laser deposition, while Cs is deposited thermally and simultaneously. We demonstrate, employing x-ray analysis and quantum efficiency measurements, that this growth method yields atomically smooth Cs3Sb photocathodes with a high quantum efficiency (>10%), even in the ultra-thin limit (<30 nm). For the Si3N4 substrate, film growth is shown to be polycrystalline, while films grown on Gr/4H–SiC show a high degree of ordering with signs of epitaxy.
Summary
The US Preventative Services Task Force (USPSTF) recommends consideration for screening for osteoporosis in women under age 65 who have an estimated 10-year major osteoporotic fracture risk ...of 9.3 % or higher. We found that this threshold for osteoporosis screening in women ages 50–64 years old has a low sensitivity to detect osteoporosis.
Introduction
The US Preventative Services Task Force (USPSTF) recommends consideration of dual-energy X-ray absorptiometry (DXA) in women under ages 50–64 with a major osteoporotic fracture (MOF) risk of 9.3 % or higher, as estimated by the fracture risk assessment tool (FRAX) tool. We assessed the performance of the 9.3 % MOF risk threshold for detecting osteoporosis and evaluated whether DXA indication appeared appropriate, based on USPSTF criteria and other risk factors, at our institution.
Methods
We performed a retrospective record review of women ages 50–64.5 years old to determine clinical factors and FRAX scores of women undergoing a DXA at our institution over a 6-month period after the USPSTF recommendations were released and evaluated the sensitivity and specificity of the 9.3 % MOF threshold to detect densitometric osteoporosis. Additionally, using the USPSTF criteria and several additional risk factors, we evaluated the extent of potentially inappropriate DXA use in women ages 50 to 64 years in a large primary care practice in an academic medical center.
Results
The analysis included 465 DXA tests. The overall sensitivity and specificity of a FRAX-calculated MOF risk ≥9.3 % was 37 and 74 %, respectively, for the detection of osteoporosis. The receiver operator characteristic curve (ROC) demonstrated an area under the curve of 0.58. Lowering the FRAX risk threshold to 5.5 % would increase the sensitivity of detecting osteoporosis in our population from 37 to 80 % while reducing the specificity from 74 to 27 %. Out of 465 DXAs, 371 (79.8 %) were classified as appropriately ordered per our pre-specified criteria. Of the 120 women with osteoporosis at the hip and/or spine based on T-score values of −2.5 or less, 14 DXAs (11.7 %) were classified as potentially inappropriate based on a FRAX-predicted MOF risk less than 9.3 % and lack of additional pre-specified risk factors.
Conclusion
We found that the USPSTF-recommended MOF risk threshold of 9.3 % for osteoporosis screening in women ages 50–64 years old has a low sensitivity to detect osteoporosis.
Considering the impact of the interweaving of diverse populations in New Orleans, American studies scholar Eric Porter writes, And with these people came intertwined histories of, among other things, ...conquest, militarism, empire building, enslavement and slave trading, revolution, institutionalized religion, the rise and fall of King Cotton, urbanization, war, racial terrorism, Jim Crow, industrialization, deindustrialization, political corruption, the development of the Keynesian state in its abridged southern form, unemployment, urban blight, white (and black) flight, urban 'renewal' and post-Jim Crow urban segregation, criminal and state violence, neoliberal social and economic policies (cuts in education, health care, and welfare), and levee breaks. The recorded benefit concert From the Big Apple to the Big Easy includes the Rebirth Brass Band processing through Madison Square Garden playing jazz funeral dirges, Spike Lee's documentary When the Levees Broke concludes with a second line through the lower-Ninth Ward, the HBO series Treme opens with a second line through the historically black Tremé neighborhood, and the 2013 "Street Kings" brass band competition sponsored by Red Bull was won by the all-female Original Pinettes Brass Band who processed down Claiborne playing the quintessential funeral dirge "Just a Closer Walk with Thee" while carrying a casket bearing the names of competing brass bands (Sakakeeny, "Street Queens").