bluuebunny/crossref_metadata_2025_split huggingface dataset:
A time‐varying angle extraction method for refined proximity group targets tracking
Authors: An Qiang , Yeh Chunmao , Lu Yaobing , Chen Xuebin , Yang Jian 
Published: April 2023

AbstractIn order to improve the detection probability of weak targets, tracking radar using sum and difference beams often adopt the method of long‐time coherent integration. However, the multidimensional migration of time‐varying targets will lead to the decline of parameter estimation accuracy. To solve this problem, this article proposes a refined angle estimation method for time‐varying targets with the traditional sum and difference beam echo model, this method compensates and searches the angle parameters of the targets based on subarray rotation invariant and focus process. In addition, this article also studies the masking problem of highly dynamic proximity group targets detection, and proposes an adaptive weighted LMS‐CLEAN based on Least Mean Square criterion, which effectively reduces the influence of masking effect on the parameter estimation accuracy of weak targets. Firstly, the proposed algorithm performs angle search and phase compensation on the pulse compression echo of sum and difference channels based on subarray rotation invariant. Secondly, focus the search matrix, reconstruct the strong target echo, and stripe it from both channels by adaptive weighting. Lastly, repeat the above steps until parameters of all targets are achieved precisely. The proposed two algorithms maintain a very low computational effort while effectively reducing the parameter estimation error, and are highly promising for engineering applications. In order to verify the effectiveness of the proposed algorithm, this article also provides some numerical experiments to compares with two existing algorithms in error performance, anti‐noise performance, and computational complexity.
Searching for compact objects in the single-lined spectroscopic binaries of the young Galactic cluster NGC 6231
Authors: Banyard G. , Mahy L. , Sana H. , Bodensteiner J. , Villaseñor J. I. , Sen K. , Langer N. , de Mink S. , Picco A. , Shenar T. 
Published: April 2023

Context. Recent evolutionary computations predict that a few percent of massive O or early-B stars in binary systems should have a dormant stellar-mass black hole (BH) as a companion. However, despite several reported candidate X-ray quiet OB+BH systems over the last couple of years, finding them with certainty remains challenging. Yet these have great importance as they can be gravitational wave (GW) source progenitors, and they are landmark systems in constraining supernova kick physics.
Aims. This work aims to characterise the hidden companions to the single-lined spectroscopic binaries (SB1s) identified in the B star population of the young open Galactic cluster NGC 6231 to find candidate systems for harbouring compact object companions.
Methods. With the orbital solutions for each SB1 constrained in a previous study, we applied Fourier spectral disentangling to multi-epoch optical VLT/FLAMES spectra of each target to extract a potential signature of a faint companion, and to identify newly disentangled double-lined spectroscopic binaries (SB2s). For targets where the disentangling does not reveal any spectral signature of a stellar companion, we performed atmospheric and evolutionary modelling on the primary (visible) star to obtain constraints on the mass and nature of the unseen companion.
Results. For seven of the 15 apparent SB1 systems, we extracted the spectral signature of a faint companion, resulting in seven newly classified SB2 systems with mass ratios down to near 0.1. From the remaining targets, for which no faint companion could be extracted from the spectra, four are found to have companion masses that lie in the predicted mass ranges of neutron stars (NSs) and BHs. Two of these targets have companion masses between 1 and 3.5 M⊙, making them potential hosts of NSs (or lower mass main sequence stars). The other two have mass ranges between 2.5 to 8 M⊙ and 1.6 and 26 M⊙, respectively, and so are identified as candidates for harbouring BH companions.
Conclusions. We present four SB1 systems in NGC 6231 that are candidates for harbouring compact objects, among which CD−41 11038 and CXOU J165421.3-415536 are the most convincing cases. We propose further observational tests involving photometric and interferometric follow-up observations of these objects.
Gas-phase electronic action absorption spectra of protonated oxygen-functionalized polycyclic aromatic hydrocarbons (OPAHs)
Authors: Rasmussen Anne P. , Wenzel Gabi , Hornekær Liv , Andersen Lars H. 
Published: April 2023

Context. Extended red emission (ERE) denotes a broad unassigned feature extending from 540 to 800 nm observed in many regions of the interstellar medium (ISM), and is thought to originate from photoluminescence of cosmic dust. However, definitive assignment of specific carriers remains to be achieved.
Aims. Our aim is to investigate the photoabsorption spectra of astrophysically relevant protonated oxygen-functionalized polycyclic aromatic hydrocarbons (OPAHs) to probe their ability to absorb photons in the near-ultraviolet (UV) and visible (vis) spectral region and to search for any low-lying electronic states that may account for the ERE.
Methods. Gas-phase electronic action absorption spectra of the protonated OPAHs were recorded in the spectral range of 200–700 nm using the ELISA ion-storage ring. Additional time-dependent density functional theory (TD-DFT) calculations were performed to compute excited state transitions that complement the experimental spectra.
Results. A set of five protonated (O)PAHs was considered, namely pentacene and the four oxygen-functionalized PAHs, pentacenequinone, pentacenetetrone, anthraquinone, and phenathrenequinone. All pentacene-related species show a main absorption band between 400 and 500 nm, while the smaller OPAHs, anthraquinone and phenanthrenequinone, generally absorb further to the blue compared to the pentacenes. Interestingly, pentacenequinone and phenanthrenequinone exhibit wide absorption plateaus towards the red side of their main absorption band(s), which places them among the potential candidates to contribute to ERE. Additional photodissociation mass spectra reveal the formation of smaller functionalized PAHs and small oxygen-bearing species.
Conclusions. Our results demonstrate the ability of OPAHs to absorb in the UV/vis spectral region. Among the four studied OPAHs, two revealed very broad absorption characteristics at wavelengths up to 700 nm, which makes them suitable candidates to contribute to a part of the ERE spectrum. Moreover, these two OPAHs, pentacenequinone and phenanthrenequinone, could dissociate efficiently into oxygen-bearing molecules and smaller functionalized PAHs in photon-dominated regions (PDRs) of the ISM.
The effect of point-of-care ultrasound on length of stay and mortality in patients with chest pain/dyspnea
Authors: Huang Chien-Tai , Chang Chih-Heng , Chen Jia-Yu , Ling Dean-An , Lee An-Fu , Wang Pei-Hsiu , Wu Chien-Kai , Ko Ying-Chih , Hsiao Yu-Tse , Lien Wan-Ching , Chang Wei-Tien , Huang Chien-Hua 
Published: April 2023

Abstract
Purpose This study aims to investigate the effects of point-of-care ultrasound (PoCUS) on length of stay (LOS) and mortality in hemodynamically stable patients with chest pain/dyspnea.
Materials and Methods The prospective study was conducted from June 2020 to May 2021. A convenience sample of adult non-traumatic patients with chest pain/dyspnea was included and evaluated by PoCUS. The primary outcome was the relationship between the door-to-PoCUS time and LOS/mortality categorized by the ST-segment elevation (STE) and non-STE on the initial electrocardiogram. The diagnostic accuracy of PoCUS was computed, compared to the final diagnosis.
Results A total of 465 patients were included. 3 of 18 patients with STE had unexpected cardiac tamponade and 1 had myocarditis with pulmonary edema. PoCUS had a minimal effect on LOS and mortality in patients with STE. In the non-STE group, the shorter door-to-PoCUS time was associated with a shorter LOS (coefficient, 1.26±0.47, p=0.008). After categorizing the timing of PoCUS as 30, 60, 90, and 120 minutes, PoCUS had a positive effect, especially when performed within 90 minutes of arrival, on LOS of less than 360 minutes (OR, 2.42, 95% CI, 1.61–3.64) and patient survival (OR, 3.32, 95% CI, 1.14–9.71). The overall diagnostic performance of PoCUS was 96.6% (95% CI, 94.9–98.2%), but lower efficacy occurred in pulmonary embolism and myocardial infarction.
Conclusion The use of PoCUS was associated with a shorter LOS and less mortality in patients with non-STE, especially when performed within 90 minutes of arrival. Although the effect on patients with STE was minimal, PoCUS played a role in discovering unexpected diagnoses.
Intra- and Interobserver Study Investigating the Adapted EFSUMB Bosniak Cyst Categorization Proposed for Contrast-Enhanced Ultrasound (CEUS) in 2020
Authors: Münch Frederic , Silivasan Emanuel Ioan Eugen , Spiesecke Paul , Göhler Friedemann , Galbavy Zaza , Eckardt Kai-Uwe , Hamm Bernd , Fischer Thomas , Lerchbaumer Markus Herbert 
Published: April 2023

Abstract
Background To investigate the inter- and intraobserver variability in comparison to an expert gold standard of the new and modified renal cyst Bosniak classification proposed for contrast-enhanced ultrasound findings (CEUS) by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) in 2020.
Materials and Methods 84 CEUS examinations for the evaluation of renal cysts were evaluated retrospectively by six readers with different levels of ultrasound expertise using the modified Bosniak classification proposed for CEUS. All cases were anonymized, and each case was rated twice in randomized order. The consensus reading of two experts served as the gold standard, to which all other readers were compared. Statistical analysis was performed using Cohen’s weighted kappa tests, where appropriate.
Results Intraobserver variability showed substantial to almost perfect agreement (lowest kappa κ=0.74; highest kappa κ=0.94), with expert level observers achieving the best results. Comparison to the gold standard was almost perfect for experts (highest kappa κ=0.95) and lower for beginner and intermediate level readers still achieving mostly substantial agreement (lowest kappa κ=0.59). Confidence of rating was highest for Bosniak classes I and IV and lowest for classes IIF and III.
Conclusion Categorization of cystic renal lesions based on the Bosniak classification proposed by the EFSUMB in 2020 showed very good reproducibility. While even less experienced observers achieved mostly substantial agreement, training remains a major factor for better diagnostic performance.
Mapping the timescale of suicidal thinking
Authors: Coppersmith Daniel D.L. , Ryan Oisín , Fortgang Rebecca G. , Millner Alexander J. , Kleiman Evan M. , Nock Matthew K. 
Published: April 2023

This study aims to identify the timescale of suicidal thinking, leveraging real-time monitoring data and a number of different analytic approaches. Participants were 105 adults with past week suicidal thoughts who completed a 42-d real-time monitoring study (total number of observations = 20,255). Participants completed two forms of real-time assessments: traditional real-time assessments (spaced hours apart each day) and high-frequency assessments (spaced 10 min apart over 1 h). We found that suicidal thinking changes rapidly. Both descriptive statistics and Markov-switching models indicated that elevated states of suicidal thinking lasted on average 1 to 3 h. Individuals exhibited heterogeneity in how often and for how long they reported elevated suicidal thinking, and our analyses suggest that different aspects of suicidal thinking operated on different timescales. Continuous-time autoregressive models suggest that current suicidal intent is predictive of future intent levels for 2 to 3 h, while current suicidal desire is predictive of future suicidal desire levels for 20 h. Multiple models found that elevated suicidal intent has on average shorter duration than elevated suicidal desire. Finally, inferences about the within-person dynamics of suicidal thinking on the basis of statistical modeling were shown to depend on the frequency at which data was sampled. For example, traditional real-time assessments estimated the duration of severe suicidal states of suicidal desire as 9.5 h, whereas the high-frequency assessments shifted the estimated duration to 1.4 h.
Cross-linking mass spectrometry discovers, evaluates, and corroborates structures and protein–protein interactions in the human cell
Authors: Bartolec Tara K. , Vázquez-Campos Xabier , Norman Alexander , Luong Clement , Johnson Marcus , Payne Richard J. , Wilkins Marc R. , Mackay Joel P. , Low Jason K. K. 
Published: April 2023

Significant recent advances in structural biology, particularly in the field of cryoelectron microscopy, have dramatically expanded our ability to create structural models of proteins and protein complexes. However, many proteins remain refractory to these approaches because of their low abundance, low stability, or—in the case of complexes—simply not having yet been analyzed. Here, we demonstrate the power of using cross-linking mass spectrometry (XL-MS) for the high-throughput experimental assessment of the structures of proteins and protein complexes. This included those produced by high-resolution but in vitro experimental data, as well as in silico predictions based on amino acid sequence alone. We present the largest XL-MS dataset to date, describing 28,910 unique residue pairs captured across 4,084 unique human proteins and 2,110 unique protein–protein interactions. We show that models of proteins and their complexes predicted by AlphaFold2, and inspired and corroborated by the XL-MS data, offer opportunities to deeply mine the structural proteome and interactome and reveal mechanisms underlying protein structure and function.
Learning fluid dynamics and the principles of flight: from primary school to STEM degrees
Authors: Pujante-Martínez Lucía , Le Clainche Soledad , Pérez José M , Ferrer Esteban 
Published: April 2023

AbstractThis article covers fluid dynamics and principles of flight. This complex topic and the related theory are typically taught in the second and third years of aerospace engineering degrees, but the present work adapts it to three different levels of learning: primary school, secondary school and science, technology, engineering and mathematics (STEM) degrees. Here we divide the topic into three sections, each one representing a project that can be developed in class. Depending on the student’s level, we propose to develop project 1 (primary school), project 2 (secondary school) or project 3 (STEM degree). The main goal of the article is twofold: (i) to increase students’ motivation from primary to university levels in the topics of mathematics and physics, showing students that the theoretical concepts that they learn in class can be applied to solve real-life problems, and (ii) to introduce original ideas for teachers to develop extracurricular activities in class, also with the aim of motivating students. Projects 1 and 3 have been carried out in class and results show that after performing these activities, students have acquired new complex knowledge and at the same time their motivation in scientific subjects has increased. Project-based learning and learning by playing are the two main methodologies of the activities presented in this article. The present work follows the spirit of ‘The Enigma of Aerodynamic Lift’ (an article recently published in Scientific American 322, 2020), and can be considered as an original extension with new material suitable for the teacher to be used in class.
Reconstructing the image scanning microscopy dataset: an inverse problem
Authors: Zunino Alessandro , Castello Marco , Vicidomini Giuseppe 
Published: April 2023

Abstract
Confocal laser-scanning microscopy (CLSM) is one of the most popular optical architectures for fluorescence imaging. In CLSM, a focused laser beam excites the fluorescence emission from a specific specimen position. Some actuators scan the probed region across the sample and a photodetector collects a single intensity value for each scan point, building a two-dimensional image pixel-by-pixel. Recently, new fast single-photon array detectors have allowed the recording of a full bi-dimensional image of the probed region for each scan point, transforming CLSM into image scanning microscopy (ISM). This latter offers significant improvements over traditional imaging but requires an optimal processing tool to extract a super-resolved image from the four-dimensional dataset. Here we describe the image formation process in ISM from a statistical point of view, and we use the Bayesian framework to formulate a multi-image deconvolution problem. Notably, the single-photon detector suffers exclusively from the photon shot noise, enabling the development of an effective likelihood model. We derive an iterative likelihood maximization algorithm and test it on experimental and simulated data. Furthermore, we demonstrate that the ISM dataset is redundant, enabling the possibility of obtaining reconstruction sampled at twice the scanning step. Our results prove that in ISM, under appropriate conditions, the Nyquist–Shannon sampling criterium is effectively relaxed. This finding can be exploited to speed up the acquisition process by a factor of four, further improving the versatility of ISM systems.
A Bayesian interpretation of the L-curve
Authors: Antoni Jérôme , Idier Jérôme , Bourguignon Sébastien 
Published: April 2023

Abstract
The L-curve is a popular heuristic to tune Tikhonov regularization in linear inverse problems. This paper shows how it naturally arises when the problem is solved from a Bayesian perspective. Specifically, it establishes that the L-curve is a graphical way of searching for the maximum a posteriori solution after marginalization over the priors. The framework is general enough to enclose the classical (linear, logarithmic and square-root) L-curves as particular cases and to allow the design of new L-curves. It also explicitly accounts for the dimensions of the inverse problem (number of observations versus number of unknowns) in regularization. Elaborating on this framework, new criteria for locating the corner of the L-curve are discovered, such as the ‘minimum speed on the curve’ and the ‘maximum angular speed’, and conditions are established for their equivalence with the maximum curvature and the marginalized maximum a posteriori. All results are supported by numerical experiments. Experiments also show that the Bayesian L-curve rooted on appropriate priors can succeed in inverse problems where the classical L-curve is prone to fail.
Structural origins of the unusual thermal stability of amorphous Cu
x
Ge50−x
Te50 (0
⩽
x
⩽
33.3)
Authors: Stellhorn J R , Paulus B , Klee B D , Inui M , Taniguchi H , Sutou Y , Hosokawa S , Pilgrim W-C 
Published: April 2023

Abstract
We have investigated the local atomic structures of several compositions of the amorphous phase of the system Cu
x
Ge

50
−
x

Te50 (

0
⩽
x
⩽
33.3

), based on extended x-ray absorption fine-structure as well as anomalous x-ray scattering experiments, and discuss the unusual trend regarding their thermal stability as a function of the Cu content. At low concentrations (

x
⩽
15

), Cu atoms tend to agglomerate in flat nanoclusters reminiscent of the crystalline phase of metallic Cu, leading to a more and more Ge-deficient Ge–Te host network structure with growing Cu content and an increasing thermal stability. At higher Cu concentrations (

x
⩾
25

), Cu is incorporated into the network, leading to an overall weaker bonding situation which is associated with a decreasing thermal stability.
Ultrafast pulse pumping of topological nanospaser
Authors: Hunley Dalton C , Oliaei Motlagh S Azar , Ghimire Rupesh , Apalkov Vadym 
Published: April 2023

Abstract
We theoretically examine a topological nanospaser that is optically pumped using an ultra-fast circularly-polarized pulse. The spasing system consists of a silver nanospheroid, which supports surface plasmon (SP) excitations, and a transition metal dichalcogenide (TMDC) monolayer nanoflake. The silver nanospheroid screens the incoming pulse and creates a non-uniform spatial distribution of electron excitations in the TMDC nanoflake. These excitations decay into the localized SPs, which can be of two types with the corresponding magnetic quantum number ±1. The amount and the type of the generated SPs depend on the intensity of the optical pulse. For small pulse amplitude, only one plasmonic mode is predominantly generated, resulting in far-field elliptically polarized radiation. For large amplitude of the optical pulse, both plasmonic modes are generated in almost the same amount, resulting in linearly polarized far-field radiation.
Ab initio lattice thermal conductivity of (Mg,Fe)O ferropericlase at the Earth’s lower mantle pressure and temperature
Authors: Dekura Haruhiko , Tsuchiya Taku 
Published: April 2023

Abstract
The effects of iron (Fe) incorporation on the lattice thermal conductivity (

κ

lat

) of MgO are investigated under the Earth’s lower mantle pressure (P) and temperature (T) condition (P > ∼20 GPa, T > ∼2000 K) based on the density-functional theory combined with the anharmonic lattice dynamics theory. The

κ

lat

of ferropericlase (FP) is determined combining the internally consistent LDA + U method and self-consistent approach to solve the phonon Boltzmann transport equation. The calculated

κ

lat

are well fitted to the extended Slack model which is proposed in this study to represent

κ

lat

in a wide volume and T range. Results demonstrate that the

κ

lat

of MgO decreases strongly by Fe incorporation. This strong negative effect is found due to decreases in phonon group velocity and lifetime. Consequently, the

κ

lat

of MgO at the core-mantle boundary condition (P∼ 136 GPa, T ∼ 4000 K) is substantially reduced from ∼40 to ∼10 W m−1 K−1 by the incorporation of Fe (12.5 mol%). The effect of Fe incorporation on the

κ

lat

of MgO is found to be insensitive to P and T, and at high T, the

κ

lat

of FP obeys a well-established T inverse relation unlike the experimental observations.
Strain-mediated ion–ion interaction in rare-earth-doped solids
Authors: Louchet-Chauvet A , Chanelière T 
Published: April 2023

Abstract
It was recently shown that the optical excitation of rare-earth ions produces a local change of the host matrix shape, attributed to a change of the rare-earth ion’s electronic orbital geometry. In this work we investigate the consequences of this piezo-orbital backaction and show from a macroscopic model how it yields a disregarded ion–ion interaction mediated by mechanical strain. This interaction scales as

1

/

r
3

, similarly to the other archetypal ion–ion interactions, namely electric and magnetic dipole–dipole interactions. We quantitatively assess and compare the magnitude of these three interactions from the angle of the instantaneous spectral diffusion mechanism, and re-examine the scientific literature in a range of rare-earth doped systems in the light of this generally underestimated contribution.