bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of different inversion strategies for electrical impedance tomography (EIT) measurements
Authors: Wang Haoran , Zimmermann Egon , Weigand Maximilian , Vereecken Harry , Huisman Johan Alexander 
Published: October 2023

SUMMARY
Electrical impedance tomography (EIT) is a promising method to image the frequency-dependent complex electrical conductivity distribution of the subsurface in the mHz to kHz frequency range. In contrast to the well-developed electrical resistivity tomography (ERT) method, the inversion approach for EIT data is less established. Different inversion strategies have been proposed, but the implications of the differences between these methods have not been investigated yet. In this study, we aim to compare four different inversion strategies for EIT measurements. The first strategy (CVI) formulates the inverse problem in the complex number domain and is mathematically the most elegant method. The second strategy (RVI) is the established real-valued inversion method, which decouples the inversion of the real and imaginary parts and completely ignores the complex nature. The third strategy (ALT) is very similar to the RVI strategy in case of small phase angles, but it considers the complex coupling in the forward operator and alternately updates the real and imaginary parts of the model in the case of large phase angles. The fourth and final strategy (CVI+) was newly formulated in this study. It fully considers the complex nature of EIT measurements but separates the treatment of the real and imaginary part in terms of the data weighting and regularization. The different inversion strategies were tested with two synthetic models. The first model has a small phase contrast and the second model has a large phase contrast. In the case of a small phase contrast, the CVI strategy was able to resolve the distribution of electrical conductivity amplitude, but the inversion result for the phase angle was less reliable. The other three strategies presented similar results and the models were well resolved within the expected data misfit. In the case of a model with large phase contrast, only the newly formulated CVI + strategy was able to produce reliable results. It was found that the extremely large phase angle can have a significant influence on the modelled amplitude of data. The cross-sensitivity (i.e. the imaginary part of the sensitivity) that describes the influence on the real part of data due to a change in the imaginary part of model, or that on the imaginary part of data due to a change in the real part of model, provided unique information during the inversion. It was concluded that the CVI + strategy is theoretically the most comprehensive and correct approach for EIT inversion, but that in the case of small phase angles the RVI strategy has the practical advantage that no complex calculations are required, which substantially reduces the required computational effort.
Black-box tests for algorithmic stability
Authors: Kim Byol , Barber Rina Foygel 
Published: October 2023

Abstract
Algorithmic stability is a concept from learning theory that expresses the degree to which changes to the input data (e.g. removal of a single data point) may affect the outputs of a regression algorithm. Knowing an algorithm’s stability properties is often useful for many downstream applications—for example, stability is known to lead to desirable generalization properties and predictive inference guarantees. However, many modern algorithms currently used in practice are too complex for a theoretical analysis of their stability properties, and thus we can only attempt to establish these properties through an empirical exploration of the algorithm’s behaviour on various datasets. In this work, we lay out a formal statistical framework for this kind of black-box testing without any assumptions on the algorithm or the data distribution, and establish fundamental bounds on the ability of any black-box test to identify algorithmic stability.
Evaluations of patient-specific bolus fabricated by mold-and-cast method using computer numerical control machine tools
Authors: Yu Geum Bong , Kwon Jimin , Chae Seunghoon , Lee Sung Young , Jung Seongmoon 
Published: October 2023

Abstract
The patient-specific bolus fabricated by a mold-and-cast method using a 3D printer (3DP) and silicon rubber has been adopted in clinical practices. Manufacturing a mold using 3DP, however, can cause time delays due to failures during the 3D printing process. Thereby, we investigated an alternative method of the mold fabrication using computer numerical control (CNC) machine tools. Treatment plans were conducted concerning a keloid scar formed on the ear and nose. The bolus structures were determined in a treatment planning system (TPS), and the molds were fabricated using the same structure file but with 3DP and CNC independently. Boluses were then manufactured using each mold with silicone rubbers. We compared the geometrical difference between the boluses and the planned structure using computed tomography (CT) images of the boluses. In addition, dosimetric differences between the two measurements using each bolus and the differences between the measured and calculated dose from TPS were evaluated using an anthropomorphic head phantom. Geometrically, the CT images of the boluses fabricated by the 3DP mold and the CNC mold showed differences compared to the planned structure within 2.6 mm of Hausdorff distance. The relative dose difference between the measurements using either bolus was within 2.3%. In conclusion, the bolus made by the CNC mold benefits from a stable fabricating process, retaining the performance of the bolus made by the 3DP mold.
Dual-energy computed tomography-based iodine concentration as a predictor of histopathological response to preoperative chemoradiotherapy for pancreatic cancer
Authors: Ohira Shingo , Ikawa Toshiki , Kanayama Naoyuki , Minamitani Masanari , Kihara Sayaka , Inui Shoki , Ueda Yoshihiro , Miyazaki Masayoshi , Yamashita Hideomi , Nishio Teiji , Koizumi Masahiko , Nakagawa Keiichi , Konishi Koji 
Published: October 2023

Abstract
To explore predictors of the histopathological response to preoperative chemoradiotherapy (CRT) in patients with pancreatic cancer (PC) using dual-energy computed tomography-reconstructed images. This retrospective study divided 40 patients who had undergone preoperative CRT (50–60 Gy in 25 fractions) followed by surgical resection into two groups: the response group (Grades II, III and IV, evaluated from surgical specimens) and the nonresponse group (Grades Ia and Ib). The computed tomography number [in Hounsfield units (HUs)] and iodine concentration (IC) were measured at the locations of the aorta, PC and pancreatic parenchyma (PP) in the contrast-enhanced 4D dual-energy computed tomography images. Logistic regression analysis was performed to identify predictors of histopathological response. Univariate analysis did not reveal a significant relation between any parameter and patient characteristics or dosimetric parameters of the treatment plan. The HU and IC values in PP and the differences in HU and IC between the PP and PC (ΔHU and ΔIC, respectively) were significant predictors for distinguishing the response (n = 24) and nonresponse (n = 16) groups (P &lt; 0.05). The IC in PP and ΔIC had a higher area under curve values [0.797 (95% confidence interval, 0.659–0.935) and 0.789 (0.650–0.928), respectively] than HU in PP and ΔHU [0.734 (0.580–0.889) and 0.721 (0.562–0.881), respectively]. The IC value could potentially be used for predicting the histopathological response in patients who have undergone preoperative CRT.
Prediction of late adverse events in pelvic cancer patients receiving definitive radiotherapy using radiation-induced gamma-H2AX foci assay
Authors: Someya Masanori , Hasegawa Tomokazu , Nakamura Asako J , Tsuchiya Takaaki , Kitagawa Mio , Gocho Toshio , Mafune Sho , Ikeuchi Yutaro , Tauchi Hiroshi , Sakata Koh-ichi 
Published: October 2023

Abstract
Radiation can induce DNA double-stranded breaks, which are typically detected by the fluorescence of phosphorylated histone H2AX. In this study, we examined the usefulness of the dynamics of radiation-induced gamma-H2AX foci of peripheral blood lymphocytes (PBLs), as a marker of DNA repair ability, in predicting late adverse events from radiotherapy. A total of 46 patients with cervical, vaginal and anal canal cancers treated with radical radiotherapy between 2014 and 2019 were included in this analysis. Concurrent chemotherapy was administered in 36 cases (78.3%). Peripheral blood was obtained before treatment, and then irradiated ex vivo with 1 Gy X-ray. The ratio of radiation-induced gamma-H2AX foci in PBLs measured at 30 min and at 4 h was defined as the foci decay ratio (FDR). With a median follow-up of 54 months, 9 patients (19.6%) were observed to have late genitourinary or gastrointestinal (GU/GI) toxicity. The FDR ranged from 0.51 to 0.74 (median 0.59), with a significantly higher incidence of Grade 1 or higher late adverse events in the FDR ≥ 0.59 group. In multivariate analysis, FDR ≥ 0.59 and hypertension also emerged as significant factors associated with the development of late toxicities. Overall, our results suggest that measurement of radiation-induced gamma-H2AX foci in PBLs may predict the risk of late GU/GI toxicities from chemoradiotherapy, which can enable tailoring the radiation dose to minimize adverse effects.
Observational investigation of the dynamical tides in massive eccentric binaries
Authors: Çakırlı Ömür , Özdarcan Orkun , Hoyman Barış 
Published: October 2023

ABSTRACT
One of the basics of astrophysics is the construction of a theory to explain tidal interactions and evolution. The accuracy of the theoretical models produced by these theories is relied upon by various other astrophysical fields. As a result, putting observational models to the test is of utmost importance. The foundation of this premise rests on the comparison between predicted models and observed stellar quantities. In order to maximize the potential of the topic, a comprehensive analysis of five massive eccentric binary systems is presented in this study, which is further compared with other sample sets to evaluate the impact of tidal interaction in massive eccentric systems. The amalgamation of radial velocity measurements with photometry has yielded a comprehensive collection of both physical and orbital parameters. The spectra of each binary system were evaluated using a standard atmospheric analysis in order to ascertain the temperatures and metallicities of each component in the binaries. The utilization of high-precision analysis enables us to ascertain the evolutionary status of the components that have been deduced from models of stellar evolution, by examining the positions of these components in the T$_{\rm eff}/\log g\,{\rm Kiel}$ diagram. The examination of the influence of tidal interaction on stars possessing radiative envelopes constitutes an important part of our research. The interpretation of our analysis is situated within the framework of the temporal scales of tidal synchronization and circularization.
Polarized resonance line transfer in a spherically symmetric medium with angle-dependent partial frequency redistribution
Authors: Sampoorna M , Supriya H D 
Published: October 2023

ABSTRACT
In a stellar atmosphere, the resonance line polarization arises from scattering of limb-darkened radiation field by atoms. This spectral line polarization gets affected particularly in the wings, when the line photons suffer scattering on electrons in thermal motion. Scattering of line photons by atoms and electrons are, respectively, described by the atomic and Thomson electron scattering redistribution functions, which in general depend on both the frequencies and directions of incident and scattered photons. In this paper, we consider the polarized spectral line formation in spherically symmetric extended and expanding media accounting for the angle-dependent partial frequency redistribution (AD-PRD) in scattering on both atoms and electrons. We solve this computationally demanding polarized transfer problem using an accelerated lambda iteration method and a method based on orders of scattering approach. In the case of expanding spherical medium, the concerned transfer problem is solved in the comoving frame. Because of the computational limitations, we consider optically thin isothermal spherically symmetric media of different extensions for the static case as well as when the velocity fields are present. For the considered model, we show that the AD-PRD effects on the linear polarization profiles are significant and have to be accounted for.
Spatially resolved Kennicutt–Schmidt relation at z ≈ 7 and its connection with the interstellar medium properties
Authors: Vallini Livia , Witstok Joris , Sommovigo Laura , Pallottini Andrea , Ferrara Andrea , Carniani Stefano , Kohandel Mahsa , Smit Renske , Gallerani Simona , Gruppioni Carlotta 
Published: October 2023

ABSTRACT
We exploit moderately resolved [O $\scriptstyle \rm III$], [C $\scriptstyle \rm II$] and dust continuum ALMA observations to derive the gas density (n), the gas-phase metallicity (Z), and the deviation from the Kennicutt–Schmidt (KS) relation (κs) on $\approx \, \rm sub-kpc$ scales in the interstellar medium (ISM) of five bright Lyman Break Galaxies at the Epoch of Reionization (z ≈ 7). To do so, we use GLAM, a state-of-art, physically motivated Bayesian model that links the [C $\scriptstyle \rm II$]and [O $\scriptstyle \rm III$]surface brightness (Σ[CII], Σ[OIII]) and the SFR surface density (ΣSFR) to n, κs, and Z. All five sources are characterized by a central starbursting region, where the Σgas versus ΣSFR align ≈10 × above the KS relation (κs ≈ 10). This translates into gas depletion times in the range tdep ≈ 80 − 250 Myr. The inner starbursting centres are characterized by higher gas density (log (n/cm−3) ≈ 2.5–3.0) and higher metallicity (log (Z/Z⊙) ≈ −0.5) than the galaxy outskirts. We derive marginally negative radial metallicity gradients (∇log Z ≈ −0.03 ± 0.07 dex/kpc), and a dust temperature (Td ≈ 32 − 38 K) that anticorrelates with the gas depletion time.
Ly α emission in low-redshift most metal-deficient compact star-forming galaxies
Authors: Izotov Y I , Thuan T X , Guseva N G , Schaerer D , Worseck G , Verhamme A 
Published: October 2023

ABSTRACT
We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of nine most metal-deficient compact star-forming galaxies with oxygen abundances 12 + log(O/H) = 6.97–7.23, redshifts z = 0.02811–0.13320, and stellar masses M⋆ ≤ 107 M⊙. We aim to study the properties of Ly α emission in these extremely metal-deficient objects. We find that all nine galaxies are Ly α emitters (LAEs). We examine various relations between the Ly α escape fraction fesc(Ly α) and other characteristics – such as absolute UV magnitude, oxygen abundance, O32 ratio, stellar mass, Lyman-alpha luminosity, and equivalent width EW(Ly α), ionizing photon production efficiency ξion and velocity separation Vsep between the two peaks of the Ly α profile – of a large sample of LAEs, including our lowest metallicity galaxies and other objects from the literature. We find a relatively tight correlation between fesc(Ly α) and two characteristics, EW(Ly α) and Vsep, whereas no correlation is found between fesc(Ly α) and the oxygen abundance. We also find a relatively tight relation between the Ly α and LyC escape fractions. We propose to use the latter relation to estimate indirectly the escaping ionizing radiation in LAEs, when direct measurements of LyC emission are not possible. We show that the global properties of low-z LAEs are very similar to those of z &gt; 6 galaxies. They are thus ideal local proxies for studying physical processes during the epoch of reionization of the Universe.
Radio haloes and relics from extended cosmic-ray ion distributions with strong diffusion in galaxy clusters
Authors: Keshet Uri 
Published: October 2023

ABSTRACT
A joint hadronic model is shown to quantitatively explain the observations of diffuse radio emission from galaxy clusters in the form of minihaloes, giant haloes, relics, and their hybrid, transitional stages. Cosmic-ray diffusion of order D ∼ 1031–32 cm2 s−1, inferred independently from relic energies, the spatial variability of giant-halo spectra, and the spectral evolution of relics, reproduces the observed spatio-spectral distributions, explains the recently discovered mega-haloes as enhanced peripheral magnetization, and quenches electron (re)acceleration by weak shocks or turbulence. For instance, the hard-to-soft evolution along secondary-electron diffusion explains both the soft spectra in most halo peripheries and relic downstreams, and the hard spectra in most halo centres and relic edges, where the photon index can reach α ≃ −0.5 regardless of the Mach number $\mathcal {M}$ of the coincident shock. Such spatio-spectral modelling, recent γ-ray observations, and additional accumulated evidence are thus shown to support a 2010 claim that the seamless transitions among minihaloes, giant haloes, and relics, their similar energetics, integrated spectra, and delineating discontinuities, the inconsistent $\mathcal {M}$ inferred from radio versus X-rays in leptonic models, and additional observations, all indicate that these diffuse radio phenomena are manifestations of the same cosmic-ray ion population, with no need to invoke less natural alternatives.
The most luminous AGN do not produce the majority of the detected stellar-mass black hole binary mergers in the local Universe
Authors: Veronesi Niccolò , Rossi Elena Maria , van Velzen Sjoert 
Published: October 2023

ABSTRACT
Despite the increasing number of gravitational wave (GW) detections, the astrophysical origin of binary black hole (BBH) mergers remains elusive. A promising formation channel for BBHs is inside accretion discs around supermassive black holes, that power active galactic nuclei (AGN). In this paper, we test for the first time the spatial correlation between observed GW events and AGN. To this end, we assemble all sky catalogues with 1,412 (242) AGN with a bolometric luminosity greater than 1045.5erg s−1 ($10^{46}\, {\rm erg\, s}^{-1}$) with spectroscopic redshift of z ≤ 0.3 from the Milliquas catalogue, version 7.7b. These AGN are cross-matched with localization volumes of BBH mergers observed in the same redshift range by the LIGO and Virgo interferometers during their first three observing runs. We find that the fraction of the detected mergers originated in AGN brighter than $10^{45.5}\, {\rm erg\, s}^{-1}$ ($10^{46}\, {\rm erg\, s}^{-1}$) cannot be higher than 0.49 (0.17) at a 95 per cent credibility level. Our upper limits imply a limited BBH merger production efficiency of the brightest AGN, while most or all GW events may still come from lower luminosity ones. Alternatively, the AGN formation path for merging stellar-mass BBHs may be actually overall subdominant in the local Universe. To our knowledge, ours are the first observational constraints on the fractional contribution of the AGN channel to the observed BBH mergers.
Bird-Snack: Bayesian inference of dust law RV distributions using SN Ia apparent colours at peak
Authors: Ward Sam M , Dhawan Suhail , Mandel Kaisey S , Grayling Matthew , Thorp Stephen 
Published: October 2023

ABSTRACT
To reduce systematic uncertainties in Type Ia supernova (SN Ia) cosmology, the host galaxy dust law shape parameter, RV, must be accurately constrained. We thus develop a computationally inexpensive pipeline, Bird-Snack, to rapidly infer dust population distributions from optical-near-infrared SN colours at peak brightness, and determine which analysis choices significantly impact the population mean RV inference, $\mu _{R_V}$. Our pipeline uses a 2D Gaussian process to measure peak BVriJH apparent magnitudes from SN light curves, and a hierarchical Bayesian model to simultaneously constrain population distributions of intrinsic and dust components. Fitting a low-to-moderate-reddening sample of 65 low-redshift SNe yields $\mu _{R_V}=2.61^{+0.38}_{-0.35}$, with $68~{{\ \rm per\ cent}}(95~{{\ \rm per\ cent}})$ posterior upper bounds on the population dispersion, $\sigma _{R_V}\lt 0.92(1.96)$. This result is robust to various analysis choices, including: the model for intrinsic colour variations, fitting the shape hyperparameter of a gamma dust extinction distribution, and cutting the sample based on the availability of data near peak. However, these choices may be important if statistical uncertainties are reduced. With larger near-future optical and near-infrared SN samples, Bird-Snack can be used to better constrain dust distributions, and investigate potential correlations with host galaxy properties. Bird-Snack is publicly available; the modular infrastructure facilitates rapid exploration of custom analysis choices, and quick fits to simulated data sets, for better interpretation of real-data inferences.
An enhanced abundance of bright galaxies in protocluster candidates at z ∼ 3–5
Authors: Toshikawa Jun , Wuyts Stijn , Kashikawa Nobunari , Liu Chengze , Sawicki Marcin , Overzier Roderik , Kubo Mariko , Uchiyama Hisakazu , Ito Kei , Bremer Malcolm , Ono Yoshiaki , Kodama Tadayuki , Lin Yen-Ting , Saito Tomoki 
Published: October 2023

ABSTRACT
We present a protocluster search covering z ∼ 3 to z ∼ 5 based on the combination of the Hyper SuprimeCam Subaru Strategic Programme and the CFHT Large Area U-band Deep Survey. We identify about 30 protocluster candidates per unit redshift over the $\sim 25\, \mathrm{deg^2}$ area of the Deep/UltraDeep layer. Protocluster candidates are selected as regions with a significantly enhanced surface density of dropout galaxies. With this large sample, we characterize the properties of their individual member galaxies. We compare the number counts of dropout galaxies in protocluster candidates with that of coeval field galaxies. Rest-frame ultraviolet (UV) bright galaxies are overabundant in protocluster candidates, a trend seen across the full redshift range studied. We do not find evidence for their spatial distribution within protocluster candidates to be distinct from their fainter counterparts, nor for their UV colour to be different from that of field galaxies with the same brightness. Cosmological simulations predict this bright-end excess, with the main cause being a richer population of massive galaxies, with only a minor contribution from an enhancement in star formation activity (and therefore UV emission) at fixed mass. U-to-K SED modelling of our observed samples supports this interpretation. This environmental differentiation in number counts is already in place at z ∼ 5, with no significant redshift dependence over the range in lookback times probed . These observational results and model predictions suggest that the cosmic clock is ahead in high-density environments.