Do MURaM and STAGGER Simulations of Solar Faculae Match Observational Signatures from Magnetic Structures?

We compare results of simulations of solar facular-like conditions performed using the numerical codes MURaM and STAGGER. Both simulation sets have a similar setup, including the initial condition of ≈200 G vertical magnetic flux. After interpolating the output physical quantities to constant optical depth, we compare them and test them against inversion results from solar observations. From the snapshots, we compute the monochromatic continuum in the visible and infrared, and the full Stokes vector of the Fe i spectral line pair around 6301–6302 Å. We compare the predicted spectral lines (at the simulation resolution and after smearing to the HINODE SP/SOT resolution) in terms of their main parameters for the Stokes I line profiles, and of their area and amplitude asymmetry for the Stokes V profiles. The codes produce magnetoconvection with similar appearance and distribution in temperature and velocity. The results also closely match the values from recent relevant solar observations. Although the overall distribution of the magnetic field is similar in both radiation-magnetohydrodynamic (RMHD) simulation sets, a detailed analysis reveals substantial disagreement in the field orientation, which we attribute to the differing boundary conditions. The resulting differences in the synthetic spectra disappear after spatial smearing to the resolution of the observations. We conclude that the two sets of simulations provide robust models of solar faculae. Nevertheless, we also find differences that call for caution when using results from RMHD simulations to interpret solar observational data.

Quality Enhancement of Gamma Camera SPECT Images Via the Taguchi-Based Optimization of Their Minimum Detectable Difference And a V-Shaped Slit Gauge

Background: This study optimized the minimum detectable difference (MDD) of gamma camera SPECT images via the Taguchi analysis and an indigenous V-shaped slit gauge. The latter was customized to satisfy the Taguchi analysis’ quantitative requirements. Methods: The slit gauge MDD quantification of derived SPECT images was based on a pair of overlapped-peak profiles obtained from a tangent slice of the V-shaped slit with two adjacent peaks. Using the revised Student’s t-test with a multiplied constant, 1.96, the MDD was defined as the minimum distance between two peak centers, which deviation was large enough to ensure a 95% confidence level of their separation. In total, eighteen combinations of six gamma camera scanned factors (A-F), namely (A) collimator, (B) detector to target distance, (C) total counts, (D) acquired energy width, (E) Matrix size, and (F) zoom of collected ROI with each of two or three levels were organized into 18 groups to collect the slit gauge images according to Taguchi L18 orthogonal array. Next, three well-trained radiologists ranked the scanned gauge images to derive the fish-bone-plot of signal-to-noise ratio (S/N, dB) and correlated ANOVA. Results: The quantified MDD was proposed to verify the optimal suggestion of gamma camera scanned protocol, and obtained the MDD as 8.44, 7.88, and 7.40 mm for the 2nd group of the original L18, conventional, and optimal presets, respectively. Conclusions: The optimal preset of gamma camera was achieved according to Taguchi analysis. The MDD-based approach was found more beneficial in evaluating the spatial resolution than the line pair/cm approach in routine quality control in this study.

The effectiveness of the Safety in Interventional Radiology (SIR) Shield in reducing droplet transmission and its effect on image quality and radiation dose

Objective: To evaluate the efficacy of a barrier shield in reducing droplet transmission and its effect on image quality and radiation dose in an interventional suite. Methods: A human cough droplet visualisation model in a supine position was developed to assess efficacy of barrier shield in reducing environmental contamination. Its effect on image quality (resolution and contrast) was evaluated via image quality test phantom. Changes in the radiation dose to patient post-shield utilisation was measured. Results: Use of the shield prevented escape of visible fluorescent cough droplets from the containment area. No subjective change in line-pair resolution was observed. No significant difference in contrast-to-noise ratio was measured. Radiation dosage to patient was increased; this is predominantly attributed to the increased air gap and not the physical properties of the shield. Conclusion: Use of the barrier shield provided an effective added layer of personal protection in the interventional radiology theatre for aerosol generating procedures. Advances in knowledge: This is the first time a human supine cough droplet visualisation has been developed. While multiple types of barrier shields have been described, this is the first systematic practical evaluation of a barrier shield designed for use in the interventional radiology theatre.

MINIMUM DETECTABLE DIFFERENCE OF CT ANGIOGRAPHY SCANS AT VARIOUS CARDIAC BEATS: EVALUATION VIA A CUSTOMIZED OBLIQUE V-SHAPED LINE GAUGE AND PMMA PHANTOM

The minimum detectable difference (MDD) at various beats/min (BPM) of CT angiography (CTA) was evaluated using an oblique V-shape line gauge and poly methyl methacrylate (PMMA) phantom in this study. The customized phantom with the size of [Formula: see text][Formula: see text]cm3 was made from a 1[Formula: see text]cm-thick PMMA. The reciprocating mechanism in the phantom was run by a step motor with an eccentric gear connected to a crank rod to provide a stable harmonic motion, simulating the cardiac beats. The MDD has a unique feature in defining the quality characteristic of CT-scanned images and provides more information than simple line pair/cm in the previous studies. The derived MDD was quantified according to various BPM, and the CTA factor combination was preset following either the conventional recommendation or the optimal one. In doing so, the performance was substantiated by the Taguchi-based signal-to-noise ratio and integrated by another index, namely, figure of merit (FOM). The MDD and corresponding [Formula: see text] (dB) changed from [Formula: see text][Formula: see text]mm to [Formula: see text][Formula: see text]mm and from 16.7[Formula: see text]dB to 14.2[Formula: see text]dB, respectively, for conventional settings; while those obtained for the optimal preset changed from [Formula: see text][Formula: see text]mm to [Formula: see text][Formula: see text]mm and from 12.2 dB to 16.4 dB, respectively of CTA at 0–90 BPM. The integrated FOM values for conventional or optimal cases were 1240 and 1337, respectively. The MDD proved to be a useful technique in justifying the CTA-scanned images. For compliance with previous studies, MDD results can be converted to the line pair/cm results, but it is more informative than the quantized number of line pairs.

PharmacoDB 2.0 : Improving scalability and transparency of in vitro pharmacogenomics analysis

Cancer pharmacogenomics studies provide valuable insights into disease progression and associations between genomic features and drug response. PharmacoDB integrates multiple cancer pharmacogenomics datasets profiling approved and investigational drugs across cell lines from diverse tissue types. The web-application enables users to efficiently navigate across datasets, view and compare drug dose-response data for a specific drug-cell line pair. In the new version of PharmacoDB (version 2.0, https://pharmacodb.ca/), we present: (i) new datasets such as NCI-60, the Profiling Relative Inhibition Simultaneously in Mixtures (PRISM) dataset, as well as updated data from the Genomics of Drug Sensitivity in Cancer (GDSC) and the Genentech Cell Line Screening Initiative (gCSI); (ii) implementation of FAIR data pipelines using ORCESTRA and PharmacoDI; (iii) enhancements to drug response analysis such as tissue distribution of dose-response metrics and biomarker analysis; (iv) improved connectivity to drug and cell line databases in the community. The web interface has been rewritten using a modern technology stack to ensure scalability and standardization to accommodate growing pharmacogenomics datasets. PharmacoDB 2.0 is a valuable tool for mining pharmacogenomics datasets, comparing and assessing drug response phenotypes of cancer models.

Braille Block Detection via Multi-Objective Optimization from an Egocentric Viewpoint

In this paper, we propose a method to detect Braille blocks from an egocentric viewpoint, which is a key part of many walking support devices for visually impaired people. Our main contribution is to cast this task as a multi-objective optimization problem and exploits both the geometric and the appearance features for detection. Specifically, two objective functions were designed under an evolutionary optimization framework with a line pair modeled as an individual (i.e., solution). Both of the objectives follow the basic characteristics of the Braille blocks, which aim to clarify the boundaries and estimate the likelihood of the Braille block surface. Our proposed method was assessed by an originally collected and annotated dataset under real scenarios. Both quantitative and qualitative experimental results show that the proposed method can detect Braille blocks under various environments. We also provide a comprehensive comparison of the detection performance with respect to different multi-objective optimization algorithms.

The NASA Mass Change Designated Observable Study: Progress and Future Plans

<p>The 2017-2027 US National Academy of Sciences Decadal Survey for Earth Science and Applications from Space classified mass change as one of five designated observables having the highest priority in terms of Earth observations required to better understand the Earth system over the next decade.  In response to this designation, NASA initiated multi-center studies with an overarching goal of defining observing system architectures for each designated observable.  Here, we discuss the progress made and future plans for the Mass Change Designated Observable study. Progress includes the development of a Science and Applications Traceability Matrix (SATM), the definition of three different architectural classes that are responsive to the designated science objectives, and a framework to quantitatively link the performance of specific architectures to the SATM.  We will describe the Value Framework that has been developed to assess the value of potential architectures in terms of science return, cost, risk, and technical maturity.  Results highlight the recommendation of satellite-satellite-tracking for the MC observing system, and have identified high value variants as a single in-line pair, dual in-line pairs, and pendulum architectures, which are similar to architectures studied by potential international partners.  The current status of the study process, and future plans will be discussed.</p>

Temporal evolution of small-scale internetwork magnetic fields in the solar photosphere

Context. While the longitudinal field that dominates in photospheric network regions has been studied extensively, small-scale transverse fields have recently been found to be ubiquitous in the quiet internetwork photosphere and this merits further study. Furthermore, few observations have been able to capture how this field evolves. Aims. We aim to statistically characterize the magnetic vector in a quiet Sun internetwork region and observe the temporal evolution of specific small-scale magnetic features. Methods. We present two high spatio-temporal resolution observations that reveal the dynamics of two disk-centre internetwork regions taken by the new GREGOR Infrared Spectrograph Integral Field Unit with the highly magnetically sensitive photospheric Fe I line pair at 15648.52 Å and 15652.87 Å. We record the full Stokes vector and apply inversions with the Stokes inversions based on response functions code to retrieve the parameters characterizing the atmosphere. We consider two inversion schemes: scheme 1 (S1), where a magnetic atmosphere is embedded in a field free medium, and scheme 2 (S2), with two magnetic models and a fixed 30% stray light component. Results. The magnetic properties produced from S1 inversions returned a median magnetic field strength of 200 and 240 G for the two datasets, respectively. We consider the median transverse (horizontal) component, among pixels with Stokes Q or U, and the median unsigned longitudinal (vertical) component, among pixels with Stokes V, above a noise threshold. We determined the former to be 263 G and 267 G, and the latter to be 131 G and 145 G, for the two datasets, respectively. Finally, we present three regions of interest, tracking the dynamics of small-scale magnetic features. We apply S1 and S2 inversions to specific profiles of interest and find that the latter produces better approximations when there is evidence of mixed polarities. We find patches of linear polarization with magnetic flux density of the order of 130−150 G and find that linear polarization appears preferentially at granule-intergranular lane boundaries. The weak magnetic field appears to be organized in terms of complex ‘loop-like’ structures, with transverse fields often flanked by opposite polarity longitudinal fields.

Hidden by bias: how standard psychophysical procedures conceal crucial aspects of peripheral visual appearance

The perception of a target depends on other stimuli surrounding it in time and space. This contextual modulation is ubiquitous in visual perception, and is usually quantified by measuring performance on sets of highly similar stimuli. Implicit or explicit comparisons among the stimuli may, however, inadvertently bias responses and conceal strong variability of target appearance. Here, we investigated the influence of contextual stimuli on the perception of a repeating pattern (a line triplet), presented in the visual periphery. In the neutral condition, the triplet was presented a single time to capture its minimally biased perception. In the similar and dissimilar conditions, it was presented within stimulus sets composed of lines similar to the triplet, and distinct shapes, respectively. The majority of observers reported perceiving a line pair in the neutral and dissimilar conditions, revealing ‘redundancy masking’, the reduction of the perceived number of repeating items. In the similar condition, by contrast, the number of lines was overestimated. Our results show that the similar context did not reveal redundancy masking which was only observed in the neutral and dissimilar context. We suggest that the influence of contextual stimuli has inadvertently concealed this crucial aspect of peripheral appearance.

On the effect of oscillatory phenomena on Stokes inversion results

Stokes inversion codes are crucial in returning properties of the solar atmosphere, such as temperature and magnetic field strength. However, the success of such algorithms to return reliable values can be hindered by the presence of oscillatory phenomena within magnetic wave guides. Returning accurate parameters is crucial to both magnetohydrodynamics (MHD) studies and solar physics in general. Here, we employ a simulation featuring propagating MHD waves within a flux tube with a known driver and atmospheric parameters. We invert the Stokes profiles for the 6301 Å and 6302 Å line pair emergent from the simulations using the well-known Stokes Inversions from Response functions code to see if the atmospheric parameters can be returned for typical spatial resolutions at ground-based observatories. The inversions return synthetic spectra comparable to the original input spectra, even with asymmetries introduced in the spectra from wave propagation in the atmosphere. The output models from the inversions match closely to the simulations in temperature, line-of-sight magnetic field and line-of-sight velocity within typical formation heights of the inverted lines. Deviations from the simulations are seen away from these height regions. The inversions results are less accurate during passage of the waves within the line formation region. The original wave period could be recovered from the atmosphere output by the inversions, with empirical mode decomposition performing better than the wavelet approach in this task. This article is part of the Theo Murphy meeting issue ‘High-resolution wave dynamics in the lower solar atmosphere’.