Systematic review of emergency department central venous and arterial catheter infection

Background: There is an extensive critical care literature for central venous catheter and arterial line infection, duration of catheterization, and compliance with infection control procedures. The emergency medicine literature, however, contains very little data on central venous catheters and arterial lines. As emergency medicine practice continues to incorporate greater numbers of critical care procedures such as central venous catheter placement, infection control is becoming a greater issue. Aims: We performed a systematic review of studies reporting baseline data of ED-placed central venous catheters and arterial lines using multiple search methods. Methods: Two reviewers independently assessed included studies using explicit criteria, including the use of EDplaced invasive lines, the presence of central line-associated bloodstream infection, and excluded case reports and review articles. Finding significant heterogeneity among studies, we performed a qualitative assessment. Results: Our search produced 504 abstracts, of which 15 studies were evaluated, and 4 studies were excluded because of quality issues leaving 11 cohort studies. Four studies calculated infection rates, ranging 0–24.1/1,000 catheter-days for central line-associated and 0–32.8/1,000 catheter-days for central line-related bloodstream infection. Average duration of catheterization was 4.9 days (range 1.6–14.1 days), and compliance with infection control procedures was 33–96.5%. The data were too poor to compare emergency department to in-hospital catheter infection rates. Conclusions: The existing data for emergency department placed invasive lines are poor, but suggest they are a source of infection, remain in place for a significant period of time, and that adherence to maximum barrier precautions is poor. Obtaining accurate rates of infection and comparison between emergency department and inpatient lines requires prospective study

The Two States of Star Forming Clouds

We examine the effects of self-gravity and magnetic fields on supersonic turbulence in isothermal molecular clouds with high resolution simulations and adaptive mesh refinement. These simulations use large root grids (512^3) to capture turbulence and four levels of refinement to capture high density, for an effective resolution of 8,196^3. Three Mach 9 simulations are performed, two super-Alfv\'enic and one trans-Alfv\'enic. We find that gravity splits the clouds into two populations, one low density turbulent state and one high density collapsing state. The low density state exhibits properties similar to non-self-gravitating in this regime, and we examine the effects of varied magnetic field strength on statistical properties: the density probability distribution function is approximately lognormal; velocity power spectral slopes decrease with field strength; alignment between velocity and magnetic field increases with field; the magnetic field probability distribution can be fit to a stretched exponential. The high density state is characterized by self-similar spheres; the density PDF is a power-law; collapse rate decreases with increasing mean field; density power spectra have positive slopes, P({\rho},k) \propto k; thermal-to-magnetic pressure ratios are unity for all simulations; dynamic-to-magnetic pressure ratios are larger than unity for all simulations; magnetic field distribution is a power-law. The high Alfv\'en Mach numbers in collapsing regions explain recent observations of magnetic influence decreasing with density. We also find that the high density state is found in filaments formed by converging flows, consistent with recent Herschel observations. Possible modifications to existing star formation theories are explored.Comment: 19 pages, 20 figure

Injury Rates in Major League Baseball during the 2020 COVID-19 Season

Background: The 2020 Major League Baseball (MLB) season was drastically altered because of the COVID-19 pandemic. The changes included an extended layoff between March and July as well as a shortened preseason. Purpose/Hypothesis: To determine the incidence and epidemiology of MLB injuries in the abbreviated 2020 season compared with prior seasons. We hypothesized that there was an increase in the overall injury rate in the 2020 season compared with the 2018-2019 seasons and that it equally affected all body regions. Study Design: Descriptive epidemiology study. Methods: The MLB transactions database was queried to find players who had been placed on the injury list between 2018 and 2020. Injuries were categorized into upper extremity, lower extremity, spine/core, and other injuries. Incidence per 1000 athlete-exposures was calculated for the prior 2 seasons (2018-2019) and for the 2020 season separately. Incidence for each category was also calculated separately for pitchers and fielders. Incidence rate ratios (IRRs) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z test for proportions was used to determine significant differences between injury incidences. Results: In 2020, the overall incidence rate per 1000 athlete-exposures was almost twice the rate compared with the 2 seasons before COVID-19 (8.66 vs 5.13; IRR, 1.69 [95% CI, 1.53-1.87]; P \u3c .001). Injury incidence increased similarly in 2020 for both pitchers (IRR, 1.68 [95% CI, 1.47-1.91]; P \u3c .001) and fielders (IRR, 1.68 [95% CI, 1.45-1.96]; P \u3c .001). Increases in injury incidence were seen in the upper extremity, spine/core, and other injury categories; however, the incidence of the lower extremity did not change significantly. Conclusion: There was a significant increase in injury incidence for both pitchers and fielders in 2020. Injury rates increased in anatomic zones of the upper extremity and spine/core but were not significantly changed in the lower extremity. The overall increase in injury rate suggests that irregular or insufficient sport-specific preparation prior to the start of the season placed athletes at a greater risk of injury when play resumed

Differential Tilt Variance Effects of Turbulence in Imagery: Comparing Simulation with Theory

Differential tilt variance is a useful metric for interpreting the distorting effects of turbulence in incoherent imaging systems. In this paper, we compare the theoretical model of differential tilt variance to simulations. Simulation is based on a Monte Carlo wave optics approach with split step propagation. Results show that the simulation closely matches theory. The results also show that care must be taken when selecting a method to estimate tilts

Resonance Broadening and Heating of Charged Particles in Magnetohydrodynamic Turbulence

The heating, acceleration, and pitch-angle scattering of charged particles by MHD turbulence are important in a wide range of astrophysical environments, including the solar wind, accreting black holes, and galaxy clusters. We simulate the interaction of high-gyrofrequency test particles with fully dynamical simulations of subsonic MHD turbulence, focusing on the parameter regime with beta ~ 1, where beta is the ratio of gas to magnetic pressure. We use the simulation results to calibrate analytical expressions for test particle velocity-space diffusion coefficients and provide simple fits that can be used in other work. The test particle velocity diffusion in our simulations is due to a combination of two processes: interactions between particles and magnetic compressions in the turbulence (as in linear transit-time damping; TTD) and what we refer to as Fermi Type-B (FTB) interactions, in which charged particles moving on field lines may be thought of as beads spiralling around moving wires. We show that test particle heating rates are consistent with a TTD resonance which is broadened according to a decorrelation prescription that is Gaussian in time. TTD dominates the heating for v_s >> v_A (e.g. electrons), where v_s is the thermal speed of species s and v_A is the Alfven speed, while FTB dominates for v_s << v_A (e.g. minor ions). Proton heating rates for beta ~ 1 are comparable to the turbulent cascade rate. Finally, we show that velocity diffusion of collisionless, large gyrofrequency particles due to large-scale MHD turbulence does not produce a power-law distribution function.Comment: 20 pages, 15 figures; accepted by The Astrophysical Journal; added clarifying appendices, but no major changes to result

Simulating Supersonic Turbulence in Magnetized Molecular Clouds

We present results of large-scale three-dimensional simulations of weakly magnetized supersonic turbulence at grid resolutions up to 1024^3 cells. Our numerical experiments are carried out with the Piecewise Parabolic Method on a Local Stencil and assume an isothermal equation of state. The turbulence is driven by a large-scale isotropic solenoidal force in a periodic computational domain and fully develops in a few flow crossing times. We then evolve the flow for a number of flow crossing times and analyze various statistical properties of the saturated turbulent state. We show that the energy transfer rate in the inertial range of scales is surprisingly close to a constant, indicating that Kolmogorov's phenomenology for incompressible turbulence can be extended to magnetized supersonic flows. We also discuss numerical dissipation effects and convergence of different turbulence diagnostics as grid resolution refines from 256^3 to 1024^3 cells.Comment: 10 pages, 3 figures, to appear in the proceedings of the DOE/SciDAC 2009 conferenc

Non-thermal radio emission from O-type stars. IV. Cyg OB2 No. 8A

We study the non-thermal radio emission of the binary Cyg OB2 No. 8A, to see if it is variable and if that variability is locked to the orbital phase. We investigate if the synchrotron emission generated in the colliding-wind region of this binary can explain the observations and we verify that our proposed model is compatible with the X-ray data. We use both new and archive radio data from the Very Large Array (VLA) to construct a light curve as a function of orbital phase. We also present new X-ray data that allow us to improve the X-ray light curve. We develop a numerical model for the colliding-wind region and the synchrotron emission it generates. The model also includes free-free absorption and emission due to the stellar winds of both stars. In this way we construct artificial radio light curves and compare them with the observed one. The observed radio fluxes show phase-locked variability. Our model can explain this variability because the synchrotron emitting region is not completely hidden by the free-free absorption. In order to obtain a better agreement for the phases of minimum and maximum flux we need to use stellar wind parameters for the binary components which are somewhat different from typical values for single stars. We verify that the change in stellar parameters does not influence the interpretation of the X-ray light curve. Our model has trouble explaining the observed radio spectral index. This could indicate the presence of clumping or porosity in the stellar wind, which - through its influence on both the Razin effect and the free-free absorption - can considerably influence the spectral index. Non-thermal radio emitters could therefore open a valuable pathway to investigate the difficult issue of clumping in stellar winds.Comment: 19 pages, 10 figures, accepted by A&

Balanced carving turns in alpine skiing

In this paper, we analyse the model of pure carving turns in alpine skiing and snowboarding based on the usual assumption of approximate balance between forces and torques acting on the skier during the turn. The approximation of torque balance yields both lower and upper limits on the skier speed, which depend only on the sidecut radius of skis and the slope gradient. We use the model to simulate carving runs on slopes of constant gradient and find that pure carving is possible only on slopes of relatively small gradient, with the critical slope angle in the range of 8∘−20∘. The exact value depends mostly on the coefficient of snow friction and to a lesser degree on the sidecut radius of skis. Comparison with the practice of ski racing shows that the upper speed limit and the related upper limit on the slope gradient set by the model are too restrictive and so must be the assumption of torque balance used in the model. A more advanced theory is needed

Association Between Renal Failure and Foot Ulcer or Lower-Extremity Amputation in Patients With Diabetes

OBJECTIVE—The objective of this study was to evaluate the association between foot ulcers (DFU) and lower-extremity amputation (LEA) and chronic kidney disease (CKD) in patients with diabetes

Exercise Training Prevents the Perivascular Adipose Tissue-induced Aortic Dysfunction with Metabolic Syndrome

The aim of the study was to determine the effects of exercise training on improving the thoracic perivascularadipose tissue (tPVAT) phenotype (inflammation, oxidative stress, and proteasome function) in metabolic syn-drome and its subsequent actions on aortic function.Methods:Lean and obese (model of metabolic syndrome) Zucker rats (n=8/group) underwent 8-weeks ofcontrol conditions or treadmill exercise (70% of max speed, 1 h/day, 5 days/week). At the end of the inter-vention, the tPVAT was removed and conditioned media was made. The cleaned aorta was attached to a forcetransducer to assess endothelium-dependent and independent dilation in the presence or absence of tPVAT-conditioned media. tPVAT gene expression, inflammatory /oxidative phenotype, and proteasome function wereassessed.Results:The mainfindings were that Ex induced: (1) a beige-like, anti-inflammatory tPVAT phenotype; (2) agreater abundance of•NO in tPVAT; (3) a reduction in tPVAT oxidant production; and (4) an improved tPVATproteasome function. Regarding aortic function, endothelium-dependent dilation was greater in exercised leanand obese groups vs. controls (p \u3c 0.05). Lean control tPVAT improved aortic relaxation, whereas obese controltPVAT decreased aortic relaxation. In contrast, the obese Ex-tPVAT increased aortic dilation, whereas the leanEx-tPVAT did not affect aortic dilation.Conclusion:Overall, exercise had the most dramatic impact on the obese tPVAT reflecting a change towards anenvironment with less oxidant load, less inflammation and improved proteasome function. Such beneficialchanges to the tPVAT micro-environment with exercise likely played a significant role in mediating the im-provement in aortic function in metabolic syndrome following 8 weeks of exercise