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Proton beams driven by chirped pulse amplified lasers have multi-picosecond duration and can isochorically and volumetrically heat material samples, potentially providing an approach for creating samples of warm dense matter with conditions not present on Earth. Envisioned on a larger scale, they could heat fusion fuel to achieve ignition. We have shown in an experiment that a kilojoule-class, multi-picosecond short pulse laser is particularly effective for heating materials. The proton beam can be focussed via target design to achieve exceptionally high flux, important for the applications mentioned. The laser irradiated spherically curved diamond-like-carbon targets with intensity 4 × 1018 W/cm2, producing proton beams with 3 MeV slope temperature. A Cu witness foil was positioned behind the curved target, and the gap between was either empty or spanned with a structure. With a structured target, the total emission of Cu Kα fluorescence was increased 18 fold and the emission profile was consistent with a tightly focussed beam. Transverse proton radiography probed the target with ps order temporal and 10 μm spatial resolution, revealing the fast-acting focussing electric field. Complementary particle-in-cell simulations show how the structures funnel protons to the tight focus. The beam of protons and neutralizing electrons induce the bright Kα emission observed and heat the Cu to 100 eV.

Intense lasers can accelerate protons in sufficient numbers and energy that the resulting beam can heat materials to exotic warm (10 s of eV temperature) states. Here we show with experimental data that a laser-driven proton beam focused onto a target heated it in a localized spot with size strongly dependent upon material and as small as 35 μm radius. Simulations indicate that cold stopping power values cannot model the intense proton beam transport in solid targets well enough to match the large differences observed. In the experiment a 74 J, 670 fs laser drove a focusing proton beam that transported through different thicknesses of solid Mylar, Al, Cu or Au, eventually heating a rear, thin, Au witness layer. The XUV emission seen from the rear of the Au indicated a clear dependence of proton beam transport upon atomic number, Z, of the transport layer: a larger and brighter emission spot was measured after proton transport through the lower Z foils even with equal mass density for supposed equivalent proton stopping range. Beam transport dynamics pertaining to the observed heated spot were investigated numerically with a particle-in-cell (PIC) code. In simulations protons moving through an Al transport layer result in higher Au temperature responsible for higher Au radiant emittance compared to a Cu transport case. The inferred finding that proton stopping varies with temperature in different materials, considerably changing the beam heating profile, can guide applications seeking to controllably heat targets with intense proton beams.

The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially and temporally coincident with the plasma neutron source. An optical Thomson scattering apparatus designed for the FuZE device measures temperatures in the range of 1-3 keV on the axis of the device, 20 cm downstream of the nose cone. The 17-fiber system measures the radial profiles of the electron temperature. Scanning the laser time with respect to the neutron pulse time over a series of discharges allows the reconstruction of the T_{e} temporal response, confirming that the electron temperature peaks simultaneously with the neutron output, as well as the pinch current and inductive voltage generated within the plasma. Comparison to spectroscopic ion temperature measurements suggests a plasma in thermal equilibrium. The elevated T_{e} confirms the presence of a plasma assembled on axis, and indicates limited radiative losses, demonstrating a basis for scaling this device toward net gain fusion conditions.

Introduction: Health professions preceptors require skills and knowledge to effectively meet the educational needs of interprofessional students in clinical environments. We implemented a mini-fellowship program to enhance the knowledge, skills, and self-efficacy of preceptors teaching students and applying quality improvement (QI) methods across disciplines and patient care settings., Methods: The design, implementation, and evaluation of the program were informed by the faculty development literature, principles of adult learning, and preceptor needs. The 3-day program included workshops on curriculum design, clinical teaching methods, QI, social determinants of health, cultural humility, and interprofessional teamwork. Quantitative and qualitative evaluation methods were used including preprogram and postprogram knowledge and self-efficacy surveys, along with end-of-session and program evaluations., Results: Five annual cohorts involving 41 preceptors with varied demographics, professions, and clinical practices completed the mini-fellowship program. Participants' percentage of items answered correctly on a QI knowledge test increased from 79.2% (pretest) to 85.5% (post-test), a gain of 6.3% (90% CI: 2.9-9.7%; P < .003). The average QI self-efficacy scores improved from 2.64 to 3.82, a gain of 1.18 points on a five-point scale ( P < .001). The average education/teaching self-efficacy increased from 2.79 to 3.80 on a five-point scale ( P < .001). Ultimately, 94% would recommend the program to other preceptors., Discussion: An interprofessional preceptor development program designed to train clinicians to effectively teach in the clinical setting and to conduct QI projects with students was achievable and effective. This program can serve as a model for academic centers charged with training future health care workers and supporting their community-based preceptors' training needs., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 The Alliance for Continuing Education in the Health Professions, the Association for Hospital Medical Education, and the Society for Academic Continuing Medical Education.)

We report the first optical Thomson scattering measurements inside a high electron temperature (≳1 keV) and moderate electron density (mid 10 16 cm -3 ) plasma. This diagnostic has been built to provide critical plasma parameters, such as electron temperature and density, for Advanced Research Projects Agency-Energy-supported fusion-energy concepts. It uses an 8 J laser at 532 nm in 1.5 ns to measure the high frequency feature of the Thomson scattering profile at 17 locations along the probe axis. It is able to measure electron density from 5 × 10 17 cm -3 to several 10 19 cm -3 and electron temperatures from tens of eV to several keV. Here, we describe the design, deployment, and analysis on the sheared flow stabilized Z-pinch machine at Zap Energy named FuZE. The probe beam is aimed at an axial distance of 20 cm from the central electrode and is timed within the temporal envelope of neutron emission. The high temperature and moderate density plasmas generated on FuZE lie in an unconventional regime for Thomson scattering as they are between tokamaks and laser-produced plasmas. We described the analysis considerations in this regime, show that the electron density was below 5 × 10 16 cm -3 at all times during these measurements, and present a sample shot where the inferred electron temperature varied from 167 ± 16 eV to 700 ± 85 eV over 1.6 cm.

The interaction of an intense laser with a solid foil target can drive [Formula: see text] TV/m electric fields, accelerating ions to MeV energies. In this study, we experimentally observe that structured targets can dramatically enhance proton acceleration in the target normal sheath acceleration regime. At the Texas Petawatt Laser facility, we compared proton acceleration from a [Formula: see text] flat Ag foil, to a fixed microtube structure 3D printed on the front side of the same foil type. A pulse length (140-450 fs) and intensity ((4-10) [Formula: see text] W/cm[Formula: see text]) study found an optimum laser configuration (140 fs, 4 [Formula: see text] W/cm[Formula: see text]), in which microtube targets increase the proton cutoff energy by 50% and the yield of highly energetic protons ([Formula: see text] MeV) by a factor of 8[Formula: see text]. When the laser intensity reaches [Formula: see text] W/cm[Formula: see text], the prepulse shutters the microtubes with an overcritical plasma, damping their performance. 2D particle-in-cell simulations are performed, with and without the preplasma profile imported, to better understand the coupling of laser energy to the microtube targets. The simulations are in qualitative agreement with the experimental results, and show that the prepulse is necessary to account for when the laser intensity is sufficiently high., (© 2022. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Laser-accelerated proton beams are applicable to several research areas within high-energy density science, including warm dense matter generation, proton radiography, and inertial confinement fusion, which all involve transport of the beam through matter. We report on experimental measurements of intense proton beam transport through plastic foam blocks. The intense proton beam was accelerated by the 10ps, 700J OMEGA EP laser irradiating a curved foil target, and focused by an attached hollow cone. The protons then entered the foam block of density 0.38g/cm^{3} and thickness 0.55 or 1.00mm. At the rear of the foam block, a Cu layer revealed the cross section of the intense beam via proton- and hot electron-induced Cu-K&#95;{α} emission. Images of x-ray emission show a bright spot on the rear Cu film indicative of a forward-directed beam without major breakup. 2D fluid-PIC simulations of the transport were conducted using a unique multi-injection source model incorporating energy-dependent beam divergence. Along with postprocessed calculations of the Cu-K&#95;{α} emission profile, simulations showed that protons retain their ballistic transport through the foam and are able to heat the foam up to several keV in temperature. The total experimental emission profile for the 1.0mm foam agrees qualitatively with the simulated profile, suggesting that the protons indeed retain their beamlike qualities.

Objectives: Graduate medical education (GME) trainees have a unique perspective from which to identify and report patient safety concerns. However, it is not known how safety reports submitted by GME trainees differ from those submitted by other clinical staff. We hypothesized that GME trainees were more likely to submit safety reports regarding transitions of care, delays in care, and lapses in communication, and reports of higher severity compared with other frontline staff such as nurses, pharmacists, and other providers., Methods: Patient safety reports submitted by clinical staff for 1 year at an academic tertiary care children's hospital were retrospectively reviewed and categorized by reporter type. Severity level and event type were analyzed by reporter type, and repeat χ2 tests were used to compare the percentage of reports at each severity level and in each event type submitted by GME trainees compared with each other reporter type., Results: Graduate medical education trainees submitted reports of greater severity (level E/F/G) compared with nurses (10% versus 5%, P = 0.021) and pharmacists (10% versus 2%, P = 0.001). A greater percent of GME trainees' reports were categorized as errors in transitions of care, diagnosis, ordering, laboratory collection, and care delays compared with several other reporter types., Conclusions: Graduate medical education trainees identify system vulnerabilities not detected by other personnel, supporting efforts to increase safety reporting by GME trainees., Competing Interests: The authors disclose no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Asthma is a common reason for admissions to the pediatric intensive care unit (PICU). Since June 2014, our institution has used a pediatric asthma clinical pathway for all patients, including those in PICU. The pathway promotes respiratory therapist-driven bronchodilator weaning based on the Modified Pulmonary Index Score (MPIS). This pathway was associated with decreased hospital length of stay (LOS) for all pediatric asthma patients; however, the effect on PICU patients was unclear. We hypothesized that the implementation of a pediatric asthma pathway would reduce hospital LOS for asthmatic patients admitted to the PICU., Methods: We retrospectively reviewed the medical records of all pediatric asthma subjects 2-17 y old admitted to our PICU before and after pathway initiation. Primary outcome was hospital LOS. Secondary outcomes were PICU LOS and time on continuous albuterol. Data were analyzed using the chi-square test for categorical data, the t test for normally distributed data, and the Mann-Whitney test for nonparametric data., Results: A total of 203 eligible subjects (49 in the pre-pathway group, 154 in the post group) were enrolled. There were no differences between groups for age, weight, gender, home medications, cause of exacerbation, medical history, or route of admission. There were significant decreases in median (interquartile range) hospital LOS (4.4 [2.9-6.6] d vs 2.7 [1.6-4.0] d, P < .001), median PICU LOS (2.1 [1.3-4.0] d vs 1.6 [0.8-2.4] d, P = .003), and median time on continuous albuterol (39 [25-85] h vs 27 [13-42] h, P = .001). Significantly more subjects in the post-pathway group were placed on high-flow nasal cannula (32% vs 6%, P = .001) or noninvasive ventilation (10% vs 4%, P = .02)., Conclusion: The implementation of an asthma pathway was associated with decreased hospital LOS, PICU LOS, and time on continuous albuterol. There was also an increase in the use of high-flow nasal cannula and noninvasive ventilation after the implementation of this clinical pathway., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2019 by Daedalus Enterprises.)

Calibrated diagnostics for energetic particle detection allow for the systematic study of charged particle sources. The Fujifilm BAS-TR imaging plate (IP) is a reusable phosphorescent detector for radiation applications such as x-ray and particle beam detection. The BAS-TR IP has been absolutely calibrated to many low-Z (low proton number) ions, and extending these calibrations to the mid-Z regime is beneficial for the study of laser-driven ion sources. The Texas Petawatt Laser was used to generate energetic ions from a 100 nm titanium foil, and charge states Ti 10+ through Ti 12+ , ranging from 6 to 27 MeV, were analyzed for calibration. A plastic detector of CR-39 with evenly placed slots was mounted in front of the IP to count the number of ions that correspond with the IP levels of photo-stimulated luminescence (PSL). A response curve was fitted to the data, yielding a model of the PSL signal vs ion energy. Comparisons to other published response curves are also presented, illustrating the trend of PSL/nucleon decreasing with increasing ion mass.

The rapid heating of a thin titanium foil by a high intensity, subpicosecond laser is studied by using a 2D narrow-band x-ray imaging and x-ray spectroscopy. A novel monochromatic imaging diagnostic tuned to 4.51 keV Ti Kα was used to successfully visualize a significantly ionized area (⟨Z⟩>17±1) of the solid density plasma to be within a ∼35  μm diameter spot in the transverse direction and 2  μm in depth. The measurements and a 2D collisional particle-in-cell simulation reveal that, in the fast isochoric heating of solid foil by an intense laser light, such a high ionization state in solid titanium is achieved by thermal diffusion from the hot preplasma in a few picoseconds after the pulse ends. The shift of Kα and formation of a missing Kα cannot be explained with the present atomic physics model. The measured Kα image is reproduced only when a phenomenological model for the Kα shift with a threshold ionization of ⟨Z⟩=17 is included. This work reveals how the ionization state and electron temperature of the isochorically heated nonequilibrium plasma are independently increased.

The sheared-flow stabilized Z pinch has demonstrated long-lived plasmas with fusion-relevant parameters. We present the first experimental results demonstrating sustained, quasi-steady-state neutron production from the fusion Z-pinch experiment, operated with a mixture of 20% deuterium/80% hydrogen by pressure. Neutron emissions lasting approximately 5  μs are reproducibly observed with pinch currents of approximately 200 kA during an approximately 16  μs period of plasma quiescence. The average neutron yield is estimated to be (1.25±0.45)×10^{5}  neutrons/pulse and scales with the square of the deuterium concentration. Coincident with the neutron signal, plasma temperatures of 1-2 keV and densities of approximately 10^{17}  cm^{-3} with 0.3 cm pinch radii are measured with fully integrated diagnostics.

Here we propose a pump-probe X-ray absorption spectroscopy temperature measurement technique appropriate for matter having temperature in the range of 10 to a few 100 eV and density up to solid density. Atomic modeling simulations indicate that for various low- to mid-Z materials in this range the energy and optical depth of bound-bound and bound-free absorption features are sensitive to temperature. We discuss sample thickness and tamp layer considerations. A series of experimental investigations was carried out using a range of laser parameters with pulse duration ≤5 ps and various pure and alloyed materials to identify backlighter sources suitable for the technique.

Simultaneous monochromatic crystal imaging at 4.5 and 8.0 keV with x-rays produced by a single short-pulse laser is presented. A layered target consisting of thin foils of titanium and copper glued together is irradiated by the 50 TW Leopard short-pulse laser housed at the Nevada Terawatt Facility. Laser-accelerated MeV fast electrons transmitting through the target induce Kα fluorescence from both foils. Two energy-selective curved crystals in the imaging diagnostic form separate monochromatic images on a single imaging detector. The experiment demonstrates simultaneous two-color monochromatic imaging of the foils on a single detector as well as Kα x-ray production at two different photon energies with a single laser beam. Application of the diagnostic technique to x-ray radiography of a high density plasma is also presented.

Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism-observed only for times before the shock breakout at the inner cone tip-is due to self-generated resistive magnetic fields of ∼0.5-1  kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence.

Objective: The Joint Commission, the Centers for Disease Control and Prevention, and the World Health Organization challenge hospitals to achieve and sustain compliance with effective hand hygiene (HH) practice; however, many inpatient units fail to achieve a high level of reliability. The aim of the project was to increase and sustain health care worker (HCW) compliance with HH protocols from 87% (level of reliability [LOR] 1) to ≥95% (LOR 2) within 9 months on 2 pediatric inpatient units in an academic children's hospital., Methods: This study was a time-series, quality-improvement project. Interventions were tested through multiple plan-do-study-act cycles on 2 pediatric inpatient units. HH compliance audits of HCWs on these units were performed randomly each week by the hospital infection prevention program. Control charts of percentages of HCW HH compliance were constructed with 3-σ (data within 3 SDs from a mean) control limits. These control limits were adjusted after achieving significant improvements in performance over time. Charts were annotated with interventions including (1) increasing awareness, (2) providing timely feedback, (3) empowering patients and families to participate in mitigation, (4) providing focused education, and (5) developing interdisciplinary HH champions., Results: HH compliance rates improved from an average of 87% (LOR 1) to ≥95% (LOR 2) within 9 months, and this improvement has been sustained for >2 years on both pediatric inpatient units., Conclusions: Significant and sustained gains in HH compliance rates of ≥95% (LOR 2) can be achieved by applying high-reliability human-factor interventions., (Copyright © 2017 by the American Academy of Pediatrics.)

We have built an absolutely calibrated, highly efficient, Bragg crystal spectrometer in von Hamos geometry. This zinc von Hamos spectrometer uses a crystal made from highly oriented pyrolytic graphite that is cylindrically bent along the non-dispersive axis. It is tuned to measure x-ray spectra in the 7-10 keV range and has been designed to be used on a Ten Inch Manipulator for the Omega and OmegaEP target chambers at the Laboratory for Laser Energetics in Rochester, USA. Significant shielding strategies and fluorescence mitigation have been implemented in addition to an imaging plate detector making it well suited for experiments in high-intensity environments. Here we present the design and absolute calibration as well as mosaicity and integrated reflectivity measurements.

Background: Asthma exacerbations are a leading cause of hospitalization among children. Despite the existence of national pediatric asthma guidelines, significant variation in care persists. At Duke Children's Hospital, we determined that our average length of stay (ALOS) and cost for pediatric asthma admissions exceeded that of our peers. Our aim was to reduce the ALOS of pediatric patients hospitalized with asthma from 2.9 days to 2.6 days within 12 months by implementing an asthma pathway within our new electronic health record., Methods: We convened a multidisciplinary committee charged with reducing variability in practice, ALOS, and cost of inpatient pediatric asthma care, while adhering to evidence-based guidelines. Interventions were tested through multiple "plan-do-study-act" cycles. Control charts of the ALOS were constructed and annotated with interventions, including testing of an asthma score, implementation of order sets, use of a respiratory therapy-driven albuterol treatment protocol, and provision of targeted education. Order set usage was audited as a process measure. Readmission rates were monitored as a balancing measure., Results: The ALOS of pediatric patients hospitalized with asthma decreased significantly from 2.9 days to 2.3 days. Comparing baseline with intervention variable direct cost data revealed a savings of $1543 per case. Improvements occurred in the context of high compliance with the asthma pathway order sets. Readmission rates remained stable throughout the study period., Conclusions: Implementation of an asthma care pathway based on the electronic health record improved the efficiency and variable direct costs of hospital care, reduced variability in practice, and ensured adherence to high-quality national guidelines., (Copyright © 2017 by the American Academy of Pediatrics.)

The interaction of a multipicosecond, kilojoule laser pulse with a surface of a solid target has been shown to produce electrons with energies far beyond the free-electron ponderomotive limit m&#95;{e}c^{2}a&#95;{0}^{2}/2. Particle-in-cell simulations indicate that an increase in the pulse duration from 1 to 10 ps leads to the formation of a low-density shelf (about 10% of the critical density). The shelf extends over 100  μm toward the vacuum side, with a nonstationary potential barrier forming in that area. Electrons reflected from the barrier gain superponderomotive energy from the potential. Some electrons experience an even greater energy gain due to ponderomotive acceleration when their "dephasing rate" R=γ-p&#95;{x}/m&#95;{e}c drops well below unity, thus increasing acceleration by a factor of 1/R. Both 1D and 2D simulations indicate that these mechanisms are responsible for the generation of extensive thermal distributions with T&#95;{e}>10  MeV and a high-energy cutoff of hundreds of MeV.

The consequences of small scale-length precursor plasmas on high-intensity laser-driven relativistic electrons are studied via experiments and simulations. Longer scale-length plasmas are shown to dramatically increase the efficiency of electron acceleration, yet, if too long, they reduce the coupling of these electrons into the solid target. Evidence for the existence of an optimal plasma scale-length is presented and estimated to be from 1 to 5μm. Experiments on the Trident laser (I=5×10(19)W/cm(2)) diagnosed via Kα emission from Cu wires attached to Au cones are quantitively reproduced using 2D particle-in-cell simulations that capture the full temporal and spatial scale of the nonlinear laser interaction and electron transport. The simulations indicate that 32%±8%(6.5%±2%) of the laser energy is coupled into electrons of all energies (1-3 MeV) reaching the inner cone tip and that, with an optimized scale-length, this could increase to 35% (9%).

Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11}  A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achieve areal densities in excess of 300 mg cm(-2) with a nanosecond-duration compression pulse--the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.

Refluxing of fast electrons generated by high-intensity, short-pulse lasers was investigated by measuring electron-induced Kα x rays from a buried tracer layer. Using planar foils of Au/Cu/CH, the 150-J, 0.7-ps TITAN short-pulse laser was focused on the gold foil to generate fast electrons and the 3-ns, 300-J long pulse beam irradiated on the CH side to create expanding plasma as a conducting medium. By delaying the short-pulse beam timing from the long pulse laser irradiation, the plasma size was varied to change electron refluxing in the target rear. The total yields and two-dimensional images of 8.05-keV Cu-Kα x ray were recorded with an x-ray spectrometer and two monochromatic crystal imagers. The measurements show that the integrated yields decrease by a factor of 10 from refluxing to the nonrefluxing limit. Similar radial profiles of the Kα images in the rear were observed at all delays. Hybrid-particle-in-cell simulations using plasma profiles calculated by a radiation-hydrodynamic code HYDRA agree well with the measured Kα yields. The simulations suggest that conducting plasma with the size of ∼300 μm in the laser direction and ∼600 μm in the lateral direction at the density of 2 × 1020 1/cm3 is sufficiently large to prevent electrons from refluxing in the target. The parameters found in this study can be useful in designing experiments utilizing a Kα x-ray source in refluxing regime or a tracer layer in nonrefluxing regime.

Background: Despite estimates that waste constitutes up to 20% of healthcare expenditures in the United States, overuse of tests and therapies is significantly under-recognized in medicine, particularly in pediatrics. The American Board of Internal Medicine Foundation developed the Choosing Wisely campaign, which challenged medical societies to develop a list of 5 things physicians and patients should question. The Society of Hospital Medicine (SHM) joined this effort in the spring of 2012. This report provides the pediatric work group's results., Methods: A work group of experienced and geographically dispersed pediatric hospitalists was convened by the Quality and Safety Committee of the SHM. This group developed an initial list of 20 recommendations, which was pared down through a modified Delphi process to the final 5 listed below., Results: The top 5 recommendations proposed for pediatric hospital medicine are: (1) Do not order chest radiographs in children with asthma or bronchiolitis. (2) Do not use systemic corticosteroids in children under 2 years of age with a lower respiratory tract infection. (3) Do not use bronchodilators in children with bronchiolitis. (4) Do not treat gastroesophageal reflux in infants routinely with acid suppression therapy. (5) Do not use continuous pulse oximetry routinely in children with acute respiratory illness unless they are on supplemental oxygen., Conclusion: We recommend that pediatric hospitalists use this list to prioritize quality improvement efforts and include issues of waste and overuse in their efforts to improve patient care., (Copyright © 2013 Society of Hospital Medicine.)

A Kirkpatrick-Baez X-ray microscope has been developed for use on the Titan laser facility at the Lawrence Livermore National Laboratory in Fast Ignition experiments. It was developed as a broadband alternative to narrow band Bragg crystal imagers for imaging Kα emission from tracer layers. A re-entrant design is employed which allows for alignment from outside the chamber. The mirrors are coated with Pt and operate at a grazing incident angle of 0.5° providing higher resolution than an equal brightness pinhole and sufficient bandwidth to image thermally shifted characteristic Kα emission from heated Cu tracer layers in Fast Ignition experiments. The superpolished substrates (<1 Å rms roughness) had a final visible wavelength roughness of 1.7 Å after coating, and exhibited a reflectivity corresponding to an X-ray wavelength roughness of 7 ± 1 Å. A unique feature of this design is that during experiments, the unfiltered direct signal along with the one-dimensional reflections are retained on the detector in order to enable a live indication of alignment and incident angle. The broad spectral window from 4 to 9 keV enables simultaneous observation of emission from several spectral regions of interest, which has been demonstrated to be particularly useful for cone-wire targets. An experimentally measured resolution of 15 μm has been obtained at the center of the field of view.

The effect of target material on fast-electron transport is investigated using a high-intensity (0.7 ps, 10(20)  W/cm2) laser pulse irradiated on multilayered solid Al targets with embedded transport (Au, Mo, Al) and tracer (Cu) layers, backed with millimeter-thick carbon foils to minimize refluxing. We consistently observed a more collimated electron beam (36% average reduction in fast-electron induced Cu Kα spot size) using a high- or mid-Z (Au or Mo) layer compared to Al. All targets showed a similar electron flux level in the central spot of the beam. Two-dimensional collisional particle-in-cell simulations showed formation of strong self-generated resistive magnetic fields in targets with a high-Z transport layer that suppressed the fast-electron beam divergence; the consequent magnetic channels guided the fast electrons to a smaller spot, in good agreement with experiments. These findings indicate that fast-electron transport can be controlled by self-generated resistive magnetic fields and may have important implications to fast ignition.

Ketamine is a well-described anesthetic and analgesic, unique in its ability to preserve laryngeal reflexes and airway protection, and offered to a wide range of patients, although not necessarily widely used. Because it is considered an anesthetic, widespread use by all sedation providers is often limited despite its long history as a safe sedative. Because of its sympathomimetic effects, ketamine may be used in patients who are hypovolemic, including those who are experiencing traumatic or obstetric emergencies. The use of ketamine in patients with epilepsy or traumatic brain injury is more controversial. This article will explore the side effects of ketamine and current research that support or discourage its use in a variety of settings.

A novel time-resolved diagnostic is used to record the critical surface motion during picosecond-scale relativistic laser interaction with a solid target. Single-shot measurements of the specular light show a redshift decreasing with time during the interaction, corresponding to a slowing-down of the hole boring process into overdense plasma. On-shot full characterization of the laser pulse enables simulations of the experiment without any free parameters. Two-dimensional particle-in-cell simulations yield redshifts that agree with the data, and support a simple explanation of the slowing-down of the critical surface based on momentum conservation between ions and reflected laser light.

The effect of increasing prepulse energy levels on the energy spectrum and coupling into forward-going electrons is evaluated in a cone-guided fast-ignition relevant geometry using cone-wire targets irradiated with a high intensity (10(20) W/cm(2)) laser pulse. Hot electron temperature and flux are inferred from Kα images and yields using hybrid particle-in-cell simulations. A two-temperature distribution of hot electrons was required to fit the full profile, with the ratio of energy in a higher energy (MeV) component increasing with a larger prepulse. As prepulse energies were increased from 8 mJ to 1 J, overall coupling from laser to all hot electrons entering the wire was found to fall from 8.4% to 2.5% while coupling into only the 1-3 MeV electrons dropped from 0.57% to 0.03%.

We report on the development and characterization of a zirconium Kα imager for high energy density physics research. The imager consists of a spherically bent quartz crystal operating at 15.7 keV photon energy. We compare the performance of the imager in terms of integrated reflectivity (R(int)) and temperature dependent collection efficiency (η(Te)) to that of the widely used Cu Kα imager. Our collisional-radiative simulations show that the new imager can be reliably used up to 250 eV plasma temperature. Monte Carlo simulations show that for a 25 μm thick tracer layer of zirconium, the contribution to Kα production from photo-pumping is only 2%. We present, for the first time, 2D spatially resolved images of zirconium plasmas generated by a high intensity short pulse laser interacting with Zr solid targets.

A high-resolution ion Doppler spectrometer (IDS) has been installed on the sustained spheromak plasma experiment to measure ion temperatures and plasma flow. The system is composed of a 1 m focal length Czerny-Turner spectrometer with a diffraction grating line density of 2400 lines/mm, which allows for first order spectra between 300 and 600 nm. A 16-channel photomultiplier tube detection assembly combined with output coupling optics provides a spectral resolution of 0.0126 nm/channel. We calculate in some detail the mapping of curved slit images onto the linear detector array elements. This is important in determining the wavelength resolution and setting the optimum vertical extent of the slit. Also, because of the small wavelength window of the IDS, a miniature fiber-optic survey spectrometer sensitive to a wavelength range 200-1100 nm and having a resolution of 0.2 nm is used to obtain a time-integrated spectrum for each shot to verify specific impurity line radiation. Several measurements validate the systems operation. Doppler broadening of C III 464.72 nm line in the plasma shows time-resolved ion temperatures up to 250 eV for hydrogen discharges, which is consistent with neutral particle energy analyzer measurements. Flow measurements show a sub-Alfvenic plasma flow ranging from 5 to 45 kms for helium discharges.

A neutral particle analyzer is used to measure the time-resolved energy spectrum of neutral hydrogen leaving a spheromak plasma. A gas cell filled with 10-50 mTorr of helium is used to strip electrons from incoming neutral hydrogen, lowering the minimum detectable energy well below that obtained with thin foils. Effective neutral particle temperature is calculated by fitting a Maxwellian energy distribution to the measured energy spectrum above and below approximately 300 eV. A computational model with approximated profiles of plasma density and neutral density is used with the measured neutral hydrogen flux to estimate the ion temperature. Measurement of the power flux due to neutral hydrogen emitted at the measurement location is extended to the whole plasma surface to estimate the total charge exchange power loss from the plasma. The initial results indicate that the charge exchange power loss represents only 2% of the total input gun power during the sustainment phase of the discharge.

Nonlinear plasma simulations of the Sustained Spheromak Physics Experiment demonstrate the role of transient effects in establishing a toroidal magnetic structure that confines internal energy. Magnetohydrodynamics modeling with temperature-dependent transport coefficients compares well with experimental measurements and shows that the second current pulse improves confinement by keeping the q profile from falling below the value of 1/2, suppressing resonant m = 1, n = 2 fluctuations.

By operating a magnetized coaxial gun in a pulsed mode it is possible to produce large voltage pulses of duration approximately 500 mus while reaching a few kV, giving a discrete input of helicity into a spheromak. In the sustained spheromak physics experiment (SSPX), it is observed that pulsing serves to nearly double the stored magnetic energy and double the temperature. We discuss these results by comparison with 3D MHD simulations of the same phenomenon.

By operating a magnetized coaxial plasma gun continuously with just sufficient current to enable plasma ejection, large gun-voltage spikes (approximately 1 kV) are produced, giving the highest sustained voltage approximately 500 V and highest sustained helicity injection rate observed in the Sustained Spheromak Physics Experiment. The spheromak magnetic field increases monotonically with time, exhibiting the lowest fluctuation levels observed during formation of any spheromak (B/B>/=2%). The results suggest an important mechanism for field generation by helicity injection, namely, the merging of helicity-carrying filaments.

Magnetic fluctuations have been reduced to approximately 1% during discharges on the Sustained Spheromak Physics Experiment by shaping the spatial distribution of the bias magnetic flux in the device. In the resulting quiescent regime, the safety factor profile is nearly flat in the plasma and the dominant ideal and resistive MHD modes are greatly reduced. During this period, the temperature profile is peaked at the magnetic axis and maps onto magnetic flux contours. Energy confinement time is improved over previous reports in a driven spheromak.