Best-fit Slope Research Articles

Precision of in vivo pressure gradient estimations using synthetic aperture ultrasound.

Non-invasive estimation of pressure differences using 2D synthetic aperture ultrasound imaging offers a precise, low-cost, and risk-free diagnostic tool. Unlike invasive techniques, this preserves natural blood flow and avoids the limitations of devices that occupy lumen space. This paper evaluates a previously published estimator, modified to incorporate Singular Value Decomposition (SVD) echo-cancellation, using data from ten healthy volunteers and one patient. It is hypothesized that the estimator will enable precise pressure differences from the common carotid artery with a coefficient of variation of approximately 10% over a 10-second data acquisition period. Here, precision is essential to demonstrate the method's consistency and its ability to differentiate between healthy and diseased arteries at the earliest possible stage. Data are acquired using a GE-9L-D, 5.2 MHz linear transducer connected to a Vantage 256 research scanner. The estimator was applied to the left common carotid artery of ten healthy volunteers, with precision being evaluated over the recorded heart cycles by using the coefficient of variation. Eight out of ten individuals showed precision below 10%, whereas two individuals showed precision above 20%. The best precision was attained by subject_03 with a coefficient of variation of 4.64% (16.1 Pa) and the worst precision was attained by subject 09 with a coefficient of variation of 23.3% (30.2 Pa). The average range of pressure differences across volunteers (from maximum positive to maximum negative pressure difference) was 297 Pa when measured across a 14 mm streamline. The corresponding average coefficient of variation was found to be 9.95% (24.6 Pa). A comparison of peak systolic velocities between the experimental scanner and the reference scanner demonstrates a strong positive linear correlation (R2 = 0.76). The corresponding slope of the linear best fit is 0.95, indicating that the relationship between the two scanners is close to a one-to-one match, with the experimental scanner's measurements being slightly less than those of the reference scanner. Finally, data attained from a single patient example shows pressure differences ranging from -61.81 Pa to 1240.82 Pa with blood velocities as high as 1.73 m/s, which is significantly higher than seen in any of the healthy volunteers, supporting the likelihood of differentiating between stenosis grades in future studies. While this study is limited to 10 healthy volunteers and one patient, a different study design is needed to quantify the severity of stenosis and correlate it with pressure differences.

The Ultraviolet Luminosity Function at 0.6 < z < 1 from UVCANDELS

UVCANDELS is a Hubble Space Telescope Cycle-26 Treasury Program awarded 164 orbits of primary ultraviolet (UV) F275W imaging and coordinated parallel optical F435W imaging in four CANDELS fields—GOODS-N, GOODS-S, EGS, and COSMOS—covering a total area of ∼426 arcmin2. This is ∼2.7 times larger than the area covered by previous deep-field space UV data combined, reaching a depth of about 27 and 28 ABmag (5σ in 0.”2 apertures) for F275W and F435W, respectively. Along with new photometric catalogs, we present an analysis of the rest-frame UV luminosity function (LF), relying on our UV-optimized aperture photometry method, yielding a factor of 1.5 increase over H-isophot aperture photometry in the signal-to-noise ratios of galaxies in our F275W imaging. Using well-tested photometric redshift measurements, we identify 5810 galaxies at redshifts 0.6 < z < 1, down to an absolute magnitude of M UV = −14.2. In order to minimize the effect of uncertainties in estimating the completeness function, especially at the faint end, we restrict our analysis to sources above 30% completeness, which provides a final sample of 4726 galaxies at −21.5 < M UV < −15.5. We performed a maximum likelihood estimate to derive the best-fit parameters of the UV LF. We report a best-fit faint-end slope of α=−1.359−0.041+0.041 at z ∼ 0.8. Creating subsamples at z ∼ 0.7 and z ∼ 0.9, we observe a possible evolution of α with redshift. The unobscured UV luminosity density at M UV < −10 is derived as ρUV=1.339−0.030+0.027(×1026ergs−1Hz−1Mpc−3) using our best-fit LF parameters. The new F275W and F435 photometric catalogs from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes.

Improving Access to Intracranial Volume Measurements for Clinical Use: Open-Source Method using Computed Tomography

Introduction: Three-dimensional measurements of intracranial volume (ICV) can guide clinical management of brain and skull disorders. However, widespread clinical access is limited by the scarcity of software methods for analyzing CT scans, which are more available than MRI images, and the inaccessibility of proprietary and expensive commercial software. The presented method can calculate ICV from CT scans, using an open-source software, 3D Slicer. Methods: The open-source workflow was optimized with a data-driven approach to find the optimal parameters for ICV accuracy. The accuracy of the open-source method was determined by comparing it to commercial and proprietary software with CT scans of pediatric hydrocephalic macrocephaly patients with craniosynostosis undergoing total vault reconstruction (N = 5 patients,15 scans). Results: An open-source pipeline that combines an initial semi-automatic segmentation of a coronal CT reconstruction with a fully automatic segmentation minimizes the ICV error. The open-source method shows excellent agreement with both the commercial and proprietary software methods (R2 = 0.998 and 95% confidence interval of best-fit line slope: [0.986; 1.047], [0.985;1.066] respectively). The mean percent difference of ICV measurements of the open-source software from the commercial software was −0.56% [95% CI: −1.08%, −0.028%] and from the proprietary software was −0.07% [95% CI: −1.26%, 1.1%]. The mean percent difference of ICV measurements of the commercial software from the proprietary software was 0.36% [95% Confidence Interval: −0.61%, 1.32%]. Conclusions: This is the first study comparing an open-source method for measuring ICV with commercial and proprietary options. A high degree of fidelity was found, confirming this open-source method as a viable option for clinicians who are looking to incorporate ICV measurements into their practice.

90Y SIR-Spheres Activity Measurement with New SIROS D-Vial Delivery Kit.

A new 90Y SIR-Spheres delivery kit (SIROS D-vial and shield) has been introduced with a different physical form from the legacy V-Vial kit. Here, we establish the dose calibrator settings and exposure-rate-to-activity conversion factor to assay 90Y SIR-Spheres activity in the new SIROS kit. Methods: Eight D-vials with initial 90Y activities from 1.2 to 6.6 GBq within acrylic shields were assayed with dose calibrators and exposure-rate meters until activities decayed to approximately 0.1 GBq. The dose calibrator settings resulting in the lowest median activity errors and the best-fit slope of exposure rate versus activity were identified. Results: SIROS D-vial 90Y activity can be accurately and reliably estimated directly using setting 51 × 10 on both the CRC-15R and the CRC-55tR dose calibrators (errors within ±0.5%) and indirectly with an exposure-rate reading at 30 cm using conversion factor 0.664 ± 0.003 GBq/(mR/h) (R 2 = 0.985). Conclusion: Dose calibrator settings and exposure-rate-to-activity conversion factor for 90Y activity assays with new SIROS kit should be updated from legacy V-Vial parameters to avoid an approximately 10% underestimation.

The AstroSat UV Deep Field North: The IRX–β Relation for the UV-selected Galaxies at z ∼ 0.5−0.7

The relation between the observed UV continuum slope (β) and the infrared excess (IRX) is used as a powerful probe to understand the nature of dust attenuation law in high-redshift galaxies. We present a study of 83 UV-selected galaxies between a redshift of 0.5 and 0.7 from the AstroSat UV Deep Field north that encloses the GOODS-North field. Using empirical relation, we estimate the observed IRX of 52 galaxies that are detected in either one or both of the Herschel PACS 100 and 160 μm bands. We further utilize the multiband photometric data in 14–18 filters from the Ultra-Violet Imaging Telescope, KPNO, Hubble Space Telescope, Spitzer, and Herschel telescopes to perform spectral energy distribution (SED) modeling. Both the observed and model-derived IRX–β values show a large scatter within the span of previously known relations, signifying diversity in dust attenuation. We found a distinct relation between the best-fit power-law slope of the modified Calzetti relation (δ) in the IRX–β plane, where the steeper SMC-like attenuation law prefers lower δ values. Our SED model-based IRX–β relation shows a preference for steeper SMC-like attenuation, which we further confirm from the agreement between extinction-corrected star formation rates derived using the Hα emission line and the observed far-ultraviolet plus reprocessed far-IR fluxes. The current study reveals a strong positive correlation between IRX and the galaxy's stellar mass between 109.5 and 1011.0 M ⊙, signifying increased dust production in more massive star-forming galaxies.

Molecular gas scaling relations for local star-forming galaxies in the low-M* regime

We derived molecular gas fractions (fmol = Mmol/M*) and depletion times (τmol = Mmol/SFR) for 353 galaxies representative of the local star-forming population with 108.5 M⊙ &lt; M* &lt; 1010.5 M⊙ drawn from the ALLSMOG and xCOLDGASS surveys of CO(2−1) and CO(1−0) line emission. By adding constraints from low-mass galaxies and upper limits for CO non-detections, we find the median molecular gas fraction of the local star-forming population to be constant at log fmol = −0.99−0.19+0.22, challenging previous reports of increased molecular gas fractions in low-mass galaxies. Above M* ∼ 1010.5 M⊙, we find the fmol versus M* relation to be sensitive to the selection criteria for star-forming galaxies. We tested the robustness of our results against different prescriptions for the CO-to-H2 conversion factor and different selection criteria for star-forming galaxies. The depletion timescale τmol weakly depends on M*, following a power law with a best-fit slope of 0.16 ± 0.03. This suggests that small variations in specific star formation rate (sSFR = SFR/M*) across the local main sequence of star-forming galaxies with M* &lt; 1010.5 M⊙ are mainly driven by differences in the efficiency of converting the available molecular gas into stars. We tested these results against a possible dependence of fmol and τmol on the surrounding (group) environment of the targets by splitting them into centrals, satellites, and isolated galaxies, and find no significant variation between these populations. We conclude that the group environment is unlikely to have a large systematic effect on the molecular gas content of star-forming galaxies in the local Universe.

Revisiting the Dust Torus Size–Luminosity Relation Based on a Uniform Reverberation-mapping Analysis

We investigate the torus size–luminosity relation of Type 1 active galactic nuclei (AGNs) based on the reverberation-mapping analysis using the light curves of the optical continuum and the IR continuum obtained with the W1 and W2 bands of the Wide-field Infrared Survey Explorer survey. The final sample consists of 446 and 416 AGNs, respectively, for W1- and W2-band light curves, covering a large dynamic range of bolometric luminosity from 1043.4 to 1047.6 erg s−1, which show reliable lag measurements based on our quality assessment analysis. After correcting for the accretion disk contamination in the observed IR flux, we constrain the torus size (R dust) and AGN bolometric luminosity (L bol) relationship with the best-fit slope of 0.39 (0.33) for the W1 (W2) band, which is shallower than expected from the dust radiation equilibrium model. By combining the previous K-band lag measurements, we find that the measured torus size depends on the observed wavelength of the dust radiation, as R dust,K : R dust,W1: R dust,W2 = 1.0:1.5:1.8 (R dust ∝ λ 0.80) at L bol = 1046 erg s−1, confirming a stratified structure of the torus, where wavelength-dependent emissions originate from distinct regions of the torus. By investigating the deviation from the best-fit torus size–luminosity relation, we find a moderate correlation between the offset from the R dust–L bol relation and Eddington ratio. This suggests a possible influence of the Eddington ratio on the observed flattening of the R dust–L bol relationship.

CHEX-MATE: Robust reconstruction of temperature profiles in galaxy clusters with XMM-Newton

The “Cluster HEritage project with XMM-Newton: Mass Assembly and Thermodynamics at the End point of structure formation” (CHEX-MATE) is a multi-year heritage program to obtain homogeneous XMM-Newton observations of a representative sample of 118 galaxy clusters. The observations are tuned to reconstruct the distribution of the main thermodynamic quantities of the intra-cluster medium up to R500 and to obtain individual mass measurements, via the hydrostatic-equilibrium equation, with a precision of 15−20%. Temperature profiles are a necessary ingredient for the scientific goals of the project and it is thus crucial to derive the best possible temperature measurements from our data. This is why we have built a new pipeline for spectral extraction and analysis of XMM-Newton data, based on a new physically motivated background model and on a Bayesian approach with Markov chain Monte Carlo methods, which we present in this paper for the first time. We applied this new method to a subset of 30 galaxy clusters representative of the CHEX-MATE sample and show that we can obtain reliable temperature measurements up to regions where the source intensity is as low as 20% of the background, keeping systematic errors below 10%. We compare the median profile of our sample and the best-fit slope at large radii with literature results and we find a good agreement with other measurements based on XMM-Newton data. Conversely, when we exclude the most contaminated regions, where the source intensity is below 20% of the background, we find significantly flatter profiles, in agreement with predictions from numerical simulations and independent measurements with a combination of Sunyaev–Zeldovich and X-ray imaging data.

The effect of surgical timing in nonmetastatic melanoma.

There is no consensus guidelines on the best timing to perform Sentinel lymph node biopsy (SLNB) in high-risk melanoma patients. We aimed to understand the impact of surgical timing on nodal upstaging in patients with cutaneous melanoma. We queried the National Cancer Database from 2004 to 2018 for patients with T2-T4, N0, M0 melanomas, who underwent melanoma excision and nodal surgery. We included patients who underwent surgery within 2-19 weeks postdiagnosis. We aimed to determine the association of surgical delay (weeks) with nodal positivity. A total of 53 355 patients were included, of whom 20.9% had positive lymph nodes. Patients underwent surgery at a median of 5 (4-7) weeks after diagnosis. The rate of positive nodes increased with increased weeks to surgery (line of best-fit slope = 0.38). Multivariable regression analysis identified an association between time to surgery and nodal positivity (2.4% increased risk per week, p < 0.05). Our analysis showed significantly increased likelihood of nodal positivity beginning 9 weeks after diagnosis (odds ratio [OR] = 1.3, p < 0.05). Furthermore, patients with T2-3 tumors had a significant increase in nodal positivity with increased time to surgery (OR = 1.03 per week, p < 0.001). However, no significant trend in nodal positivity was identified for patients with T4 melanomas (OR = 1.01 per week, p = 0.596). Surgery within 9 weeks of melanoma diagnosis was not associated with increased likelihood of nodal positivity. These data can guide clinical conversations regarding the importance of surgical timing for melanoma.

Measuring the X-ray luminosities of DESI groups from eROSITA Final Equatorial-Depth Survey – I. X-ray luminosity–halo mass scaling relation

ABSTRACT We use the eROSITA Final Equatorial-Depth Survey (eFEDS) to measure the rest-frame 0.1–2.4 keV band X-ray luminosities of ∼600 000 DESI groups using two different algorithms in the overlap region of the two observations. These groups span a large redshift range of 0.0 ≤ zg ≤ 1.0 and group mass range of $10^{10.76}\, h^{-1}\, \mathrm{M}_{\odot } \le M_h \le 10^{15.0}\, h^{-1}\, \mathrm{M}_{\odot }$. (1) Using the blind detection pipeline of eFEDS, we find that 10932 X-ray emission peaks can be cross-matched with our groups, ∼38 per cent of which have a signal-to-noise ratio $\rm {S}/\rm {N} \ge 3$ in X-ray detection. Comparing to the numbers reported in previous studies, this matched sample size is a factor of ∼6 larger. (2) By stacking X-ray maps around groups with similar masses and redshifts, we measure the average X-ray luminosity of groups as a function of halo mass in five redshift bins. We find that in a wide halo mass range, the X-ray luminosity, LX, is roughly linearly proportional to Mh and quite independent to the redshift of the groups. (3) We use a Poisson distribution to model the X-ray luminosities obtained using two different algorithms and obtain the best-fit $L_{\rm X}=10^{28.46\pm 0.03}M_{\rm h}^{1.024\pm 0.002}$ and $L_{\rm X}=10^{26.73 \pm 0.04}M_{\rm h}^{1.140 \pm 0.003}$ scaling relations, respectively. The best-fit slopes are flatter than the results previously obtained but closer to a self-similar prediction.

ThePlanckclusters in the LOFAR sky

Context.The footprint of the recent second data release of the LOFAR Two-metre Sky Survey (LoTSS-DR2) covers 309PlanckSunyaev-Zeldovich (SZ) selected galaxy clusters, 83 of which host a radio halo and 26 host a radio relic(s). It provides an excellent opportunity to statistically study the properties of extended cluster radio sources, especially their connection with merging activities.Aims.We quantify cluster dynamic states to investigate their relation with the occurrence of extended radio sources. We also search for connections between intracluster medium (ICM) turbulence and nonthermal characteristics of radio halos in the LoTSS-DR2.Methods.We analyzedXMM-NewtonandChandraarchival X-ray data of allPlanckSZ clusters in the footprint of LoTSS-DR2. We computed concentration parameters and centroid shifts that indicate the dynamic states of the clusters. We also performed a power spectral analysis of the X-ray surface brightness fluctuations to investigate large-scale density perturbations and estimate the turbulent velocity dispersion. Furthermore, we searched for the relation between radio halo power and the turbulent dissipation flux channeled to particle acceleration.Results.The concentration parameters measured by the two telescopes agree well, but the centroid shift has a larger scatter. The surface brightness power spectral analysis results in a large scatter of the surface brightness and density fluctuation amplitudes. We therefore only found a marginal anticorrelation between density fluctuations and cluster relaxation state, and we did not find a correlation between density fluctuations and radio halo power. Nevertheless, the injected power for particle acceleration calculated from turbulent dissipation is correlated with the radio halo power, where the best-fit unity slope supports the turbulent (re)acceleration scenario. Two different acceleration models, transit-time damping and adiabatic stochastic acceleration, cannot be distinguished due to the large scatter of the estimated turbulent Mach number. We introduced a new quantity [kBT ⋅ YX]rRH, which is proportional to the turbulent acceleration power assuming a constant Mach number. This quantity is strongly correlated with radio halo power, where the slope is also unity.

Magnitude and Slip Scaling Relations for Fault-Based Seismic Hazard

ABSTRACTScaling relations play an important role in fault-based seismic hazard estimates. Scaling relations impact estimates of the sizes and rate for a given fault area. Here, we examine which relations are the most useful for these estimates and issues that arise. These include the depth of large event ruptures, transient deepening of seismicity following large events, difficulties in using classical continuum exponent fits, and the importance of large event asymptotics. A new analysis of land-based data calls into question nonspecific exponent fitting, which is a standard practice. We show a dependence on the lower and upper cut-off magnitudes in the data in the best-fitting slope parameter relating magnitude to log area with this approach. We show as well a dependence on assumed data uncertainties. These sensitivities make using this quite standard approach very problematic. Based on this evidence and other factors, we propose recommendations for the minimal branch sets, which preserve epistemic uncertainty for use in fault-based seismic hazard estimates.

Global Solar Radiation Forecasting Based on Hybrid Model with Combinations of Meteorological Parameters: Morocco Case Study

The adequate modeling and estimation of solar radiation plays a vital role in designing solar energy applications. In fact, unnecessary environmental changes result in several problems with the components of solar photovoltaic and affects the energy generation network. Various computational algorithms have been developed over the past decades to improve the efficiency of predicting solar radiation with various input characteristics. This research provides five approaches for forecasting daily global solar radiation (GSR) in two Moroccan cities, Tetouan and Tangier. In this regard, autoregressive integrated moving average (ARIMA), autoregressive moving average (ARMA), feed forward back propagation neural networks (FFBP), hybrid ARIMA-FFBP, and hybrid ARMA-FFBP were selected to compare and forecast the daily global solar radiation with different combinations of meteorological parameters. In addition, the performance in three approaches has been calculated in terms of the statistical metric correlation coefficient (R2), root means square error (RMSE), stand deviation (σ), the slope of best fit (SBF), legate’s coefficient of efficiency (LCE), and Wilmott’s index of agreement (WIA). The best model is selected by using the computed statistical metric, which is present, and the optimal value. The R2 of the forecasted ARIMA, ARMA, FFBP, hybrid ARIMA-FFBP, and ARMA-FFBP models is varying between 0.9472% and 0.9931%. The range value of SPE is varying between 0.8435 and 0.9296. The range value of LCE is 0.8954 and 0.9696 and the range value of WIA is 0.9491 and 0.9945. The outcomes show that the hybrid ARIMA–FFBP and hybrid ARMA–FFBP techniques are more effective than other approaches due to the improved correlation coefficient (R2).

Multifrequency variability study of flat-spectrum radio quasar PKS 0346-27

ABSTRACT We have presented a multiwavelength temporal and spectral study of the blazar PKS 0346-27 for the period 2019 January–2021 December (MJD 58484–59575) using data from Fermi-LAT (γ-rays), Swift-XRT (X-rays), and Swift-UVOT (ultraviolet and optical). We identified multiple flaring episodes by analysing the gamma-ray light curve generated from the Fermi-LAT data over a 2-yr period. The light curves of these individual gamma-ray flares with 1-d binning were then modelled using a sum-of-exponentials fit. We found the minimum variability times for the gamma-ray light curve to be 1.34 ± 0.3 d and a range of 0.1–3.2 d for the Swift wavelengths, suggesting the compactness of the source. The broad-band emission mechanism was studied by modelling the simultaneous multiwaveband spectral energy distributions (SEDs) using the one-zone leptonic emission mechanism. We found that the optical-UV and X-ray data can be explained by the synchrotron and synchrotron self-Compton (SSC) emissions. However, the disc component of the external Compton (EC) radiation is dominant at higher energies with contributions from the EC broad-line region component and SSC. Further, we performed a power spectral density analysis with data from the gamma-ray light curve using the power spectrum response method. With the power-law model, the best-fitting slope of 2.15 ± 0.87 was found. This source could be a promising target for the upcoming Cherenkov telescope array for its harder spectrum at lower energies (tens of GeV).

Faint Stars in a Faint Galaxy. II. The Low-mass Stellar Initial Mass Function of the Boötes I Ultrafaint Dwarf Spheroidal Galaxy

This paper presents improved constraints on the low-mass stellar initial mass function (IMF) of the Boötes I (Boo I) ultrafaint dwarf galaxy, based on our analysis of recent deep imaging from the Hubble Space Telescope. The identification of candidate stellar members of Boo I in the photometric catalog produced from these data was achieved using a Bayesian approach, informed by complementary archival imaging data for the Hubble Ultra Deep Field. Additionally, the existence of earlier-epoch data for the fields in Boo I allowed us to derive proper motions for a subset of the sources and thus identify and remove likely Milky Way stars. We were also able to determine the absolute proper motion of Boo I, and our result is in agreement with, but completely independent of, the measurement(s) by Gaia. The best-fitting parameter values of three different forms of the low-mass IMF were then obtained through forward modeling of the color–magnitude data for likely Boo I member stars within an approximate Bayesian computation Markov Chain Monte Carlo algorithm. The best-fitting single power-law IMF slope is , while the best-fitting broken power-law slopes are and . The best-fitting lognormal characteristic mass and width parameters are and . These broken power-law and lognormal IMF parameters for Boo I are consistent with published results for the stars within the Milky Way, and thus it is plausible that Boötes I and the Milky Way are populated by the same stellar IMF.

Magnetic field evolution in cosmic filaments with LOFAR data

ABSTRACT Measuring the magnetic field in cosmic filaments reveals how the Universe is magnetized and the process that magnetized it. Using the Rotation Measures (RM) at 144 MHz from the LoTSS DR2 data, we analyse the rms of the RM extragalactic component as a function of redshift to investigate the evolution with redshift of the magnetic field in filaments. From previous results, we find that the extragalactic term of the RM rms at 144 MHz is dominated by the contribution from filaments (more than 90 per cent). Including an error term to account for the minor contribution local to the sources, we fit the data with a model of the physical filament magnetic field, evolving as $B_f = B_{f,0}\, (1+z)^\alpha$ and with a density drawn from cosmological simulations of five magnetogenesis scenarios. We find that the best-fitting slope is in the range α = [ − 0.2, 0.1] with uncertainty of σα = 0.4–0.5, which is consistent with no evolution. The comoving field decreases with redshift with a slope of γ = α − 2 = [ − 2.2, −1.9]. The mean field strength at z = 0 is in the range Bf, 0 = 39–84 nG. For a typical filament gas overdensity of δg = 10 the filament field strength at z = 0 is in the range $B_{f,0}^{10}=8$–26 nG. A primordial stochastic magnetic field model with initial comoving field of BMpc = 0.04–0.11 nG is favoured. The primordial uniform field model is rejected.

Patterns of Skills Acquisition in Anesthesiologists During Simulated Interscalene Block Training on a Soft Embalmed Thiel Cadaver: Cohort Study.

BackgroundThe demand for regional anesthesia for major surgery has increased considerably, but only a small number of anesthesiologists can provide such care. Simulations may improve clinical performance. However, opportunities to rehearse procedures are limited, and the clinical educational outcomes prescribed by the Royal College of Anesthesiologists training curriculum 2021 are difficult to attain. Educational paradigms, such as mastery learning and dedicated practice, are increasingly being used to teach technical skills to enhance skills acquisition. Moreover, high-fidelity, resilient cadaver simulators are now available: the soft embalmed Thiel cadaver shows physical characteristics and functional alignment similar to those of patients. Tissue elasticity allows tissues to expand and relax, fluid to drain away, and hundreds of repeated injections to be tolerated without causing damage. Learning curves and their intra- and interindividual dynamics have not hitherto been measured on the Thiel cadaver simulator using the mastery learning and dedicated practice educational paradigm coupled with validated, quantitative metrics, such as checklists, eye tracking metrics, and self-rating scores.ObjectiveOur primary objective was to measure the learning slopes of the scanning and needling phases of an interscalene block conducted repeatedly on a soft embalmed Thiel cadaver over a 3-hour period of training.MethodsA total of 30 anesthesiologists, with a wide range of experience, conducted up to 60 ultrasound-guided interscalene blocks over 3 hours on the left side of 2 soft embalmed Thiel cadavers. The duration of the scanning and needling phases was defined as the time taken to perform all the steps correctly. The primary outcome was the best-fit linear slope of the log-log transformed time to complete each phase. Our secondary objectives were to measure preprocedural psychometrics, describe deviations from the learning slope, correlate scanning and needling phase data, characterize skills according to clinical grade, measure learning curves using objective eye gaze tracking and subjective self-rating measures, and use cluster analysis to categorize performance irrespective of grade.ResultsThe median (IQR; range) log-log learning slopes were −0.47 (−0.62 to −0.32; −0.96 to 0.30) and −0.23 (−0.34 to −0.19; −0.71 to 0.27) during the scanning and needling phases, respectively. Locally Weighted Scatterplot Smoother curves showed wide variability in within-participant performance. The learning slopes of the scanning and needling phases correlated: ρ=0.55 (0.23-0.76), P<.001, and ρ=−0.72 (−0.46 to −0.87), P<.001, respectively. Eye gaze fixation count and glance count during the scanning and needling phases best reflected block duration. Using clustering techniques, fixation count and glance were used to identify 4 distinct patterns of learning behavior.ConclusionsWe quantified learning slopes by log-log transformation of the time taken to complete the scanning and needling phases of interscalene blocks and identified intraindividual and interindividual patterns of variability.

The eROSITA Final Equatorial-Depth Survey (eFEDS)

Context.Scaling relations link the physical properties of clusters at cosmic scales. They are used to probe the evolution of large-scale structure, estimate observables of clusters, and constrain cosmological parameters through cluster counts.Aims.We investigate the scaling relations between X-ray observables of the clusters detected in the eFEDS field using Spectrum-Roentgen-Gamma/eROSITA observations taking into account the selection effects and the distributions of observables with cosmic time.Methods.We extract X-ray observables (LX,Lbol,T,Mgas,YX) withinR500for the sample of 542 clusters in the eFEDS field. By applying detection and extent likelihood cuts, we construct a subsample of 265 clusters with a contamination level of &lt;10% (including AGNs and spurious fluctuations) to be used in our scaling relations analysis. The selection function based on the state-of-the-art simulations of the eROSITA sky is fully accounted for in our work.Results.We provide the X-ray observables in the core-included &lt;R500and core-excised 0.15R500-R500apertures for 542 galaxy clusters and groups detected in the eFEDS field. Additionally, we present our best-fit results for the normalization, slope, redshift evolution, and intrinsic scatter parameters of the X-ray scaling relations betweenLX-T,LX-Mgas,LX-YX,Lbol-T,Lbol-Mgas,Lbol-YX, andMgas-T. We find that the best-fit slopes significantly deviate from the self-similar model at a &gt;4σ confidence level, but our results are nevertheless in good agreement with the simulations including non-gravitational physics, and the recent results that take into account selection effects.Conclusions.The strong deviations we find from the self-similar scenario indicate that the non-gravitational effects play an important role in shaping the observed physical state of clusters. This work extends the scaling relations to the low-mass, low-luminosity galaxy cluster and group regime using eFEDS observations, demonstrating the ability of eROSITA to measure emission from the intracluster medium out toR500with survey-depth exposures and constrain the scaling relations in a wide mass-luminosity-redshift range.

Evaluation of the dilational modulus of protein films by pendant bubble tensiometry

A new approach for evaluating the dilational modulus of an adsorbed protein film was proposed in this study; wherein, the air-water interface of Bovine serum albumin (BSA) aqueous solution was not subjected to a forced perturbation. The approach involved: (i) monitoring the relaxations of surface tension (ST), surface area (SA), and ambient/solution temperature of aqueous bovine serum albumin (BSA) solution using a pendant bubble tensiometer and (ii) detecting the numerous minute and low-frequency interfacial perturbances in the SA and ST relaxations (resultant from the minute variations in ambient temperature) at the latter stages of BSA adsorption process. For these perturbances, their surface dilational rate (dlnA/dt) and rate of ST change (dγ/dt) were determined, and then the dilational modulus (E = dγ/dlnA) was obtained from the slope of the linear best-fit in the plot of dγ/dt vs dlnA/dt. Using this approach, the dilational modulus of the adsorbed BSA film at a concentration of 0.052 and 15 (10−10 mol/cm3) was found to be 43 and 30 mN/m, respectively.

Association of BMI and Change in Weight With Mortality in Patients With Fibrotic Interstitial Lung Disease

Mortality risk assessment in interstitial lung disease (ILD) is challenging. Our objective was to determine the prognostic significance of BMI and change in weight in the most common fibrotic ILD subtypes. Could BMI and weight loss over time be reliable prognostic indicators in patients with fibrotic ILD? This observational retrospective multicenter cohort study enrolled patients with fibrotic ILD from the six-center CAnadian REgistry for Pulmonary Fibrosis (CARE-PF, derivation) and the ILD registry at the University of California, San Francisco (UCSF, validation). Patients were subcategorized as underweight (BMI< 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), or obese (BMI > 30). Annual change in weight was calculated for all years of follow-up as the slope of best fit using the least square method based on every available measurement. Separate multivariable analyses evaluated the associations of BMI and change in weight with mortality, adjusting for common prognostic variables. The derivation and validation cohorts included 1,786 and 1,779 patients, respectively. Compared with patients with normal BMI, mortality was highest in patients who were underweight (hazard ratio [HR], 3.19; 95%CI, 1.88-5.43; P< .001) and was lowest in those who were overweight (HR, 0.52; 95%CI, 0.36-0.75; P< .001) or obese (HR, 0.55; 95%CI, 0.37-0.83; P< .001) in the analysis adjusted for the ILD-GAP (gender, age, physiology) Index. Patients who had a weight loss of at least 2kg within 1 year had increased risk of death in the subsequent year (HR, 1.41; 95%CI, 1.01-1.97; P= .04) after adjustment for the ILD-GAP Index and baseline BMI category, with a plateau in risk for patients with greater weight loss. Consistent results were observed in the validation cohort. Both BMI and weight loss are independently associated with 1-year mortality in fibrotic ILD. BMI and weight loss may be clinically useful prognostic indicators in fibrotic ILD.