bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonreciprocal Phonon Laser in an Asymmetric Cavity with an Atomic Ensemble
Authors: Huang 黄 Kai-Wei 凯伟 , Wang 王 Xin 鑫 , Qiu 邱 Qing-Yang 庆洋 , Wu 吴 Long 龙 , Xiong 熊 Hao 豪
Published: September 2023

Phonon lasers, as a novel kind of lasers for generating coherent sound oscillation, has attracted extensive attention. Here, we theoretically propose a nonreciprocal phonon laser in a hybrid optomechanical system, which is composed of an asymmetric Fabry–Pérot cavity, an ensemble of N identical two-level atoms, and a mechanical oscillator. The effective driving amplitude related to driving direction leads to an obvious difference in mechanical gain and threshold power, bringing about a nonreciprocal phonon laser. In addition, the dependence of the phonon laser on the atomic parameters is also discussed, including the decay rate of the atoms and the coupling strength between the atoms and the cavity field, which provides an additional degree of freedom to control the phonon laser action. Our work provides a path to realizing a phonon laser in an atoms-cavity optomechanical system and may aid the manufacture of directional coherent phonon sources.
Testing Lorentz symmetry with space-based gravitational-wave detectors
Authors: Qin Cheng-Gang , Ke Jun , Li Qin , Chen Ya-Fen , Luo Jie , Tan Yu-Jie , Shao Cheng-Gang
Published: September 2023

Lorentz symmetry (LS), one of the most fundamental physical symmetries, has been extensively studied in the context of quantum gravity and unification theories. Many of these theories predict a LS violation, which could arise from the discreteness of spacetime, or extra dimensions. Standard-model extension (SME) is an effective field theory to describe Lorentz violation whose effects can be explored using precision instruments such as atomic clocks and gravitational-wave (GW) detectors. Considering the pure-gravity sector and matter-gravity coupling sector in the SME, we studied the leading Lorentz-violating modifications to the time delay of light and the relativistic frequency shift of the clock in the space-based GW detectors. We found that the six data streams from the GW mission can construct various combinations of measurement signals, such as single-arm round-trip path, interference path, triangular round-trip path, etc. These measurements are sensitive to the different combinations of SME coefficients and provide novel linear combinations of SME coefficients different from previous studies. Based on the orbits of TianQin, LISA, and Taiji missions, we calculated the response of Lorentz-violating effects on the combinations of the measurement signal data streams. Our results allow us to estimate the sensitivities for SME coefficients: 10−6 for the gravity sector coefficient

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Inverse radiative transfer with goal-oriented hp-adaptive mesh refinement: adaptive-mesh inversion
Authors: Du Shukai , Stechmann Samuel N
Published: September 2023

The inverse problem for radiative transfer is important in many applications, such as optical tomography and remote sensing. Major challenges include large memory requirements and computational expense, which arise from high-dimensionality and the need for iterations in solving the inverse problem. Here, to alleviate these issues, we propose adaptive-mesh inversion: a goal-oriented hp-adaptive mesh refinement method for solving inverse radiative transfer problems. One novel aspect here is that the two optimizations (one for inversion, and one for mesh adaptivity) are treated simultaneously and blended together. By exploiting the connection between duality-based mesh adaptivity and adjoint-based inversion techniques, we propose a goal-oriented error estimator, which is cheap to compute, and can efficiently guide the mesh-refinement to numerically solve the inverse problem. We use discontinuous Galerkin spectral element methods to discretize the forward and the adjoint problems. Then, based on the goal-oriented error estimator, we propose an hp-adaptive algorithm to refine the meshes. Numerical experiments are presented at the end and show convergence speed-up and reduced memory occupation by the goal-oriented mesh adaptive method.
Integrated navigation model based on TDCP constrained algorithm
Authors: Liu Yanlong , Li Zengke , Ning Yipeng
Published: September 2023

The velocity information estimated by the global navigation satellite system (GNSS) receiver is an important element for the dynamic alignment of the inertial navigation system, and it is of great significance to analyze it deeply and meticulously. A variety of GNSS velocity measurement models show different characteristics in a changeable environment, and this status quo is bound to break the monotonous situation in which the Doppler model is widely used. In this regard, this paper applies different GNSS velocity measurement models to strap-down interial navigation system (SINS) dynamic alignment and continuous observation. In addition, aiming at the shortcomings of the traditional time-differenced carrier phase (TDCP) algorithm, an optimization method is deduced from the formula level, and two effective constraint algorithms are given. Then, according to the vehicle test results, comprehensively compare the integrated navigation performance of various speed measurement models, and analyze the improvement effect of the proposed TDCP algorithm. This paper provides a summary for the comprehensive study of GNSS velocity measurement model and the application of optimized carrier phase to integrated navigation, which has certain practical value.
Room-temperature-processed synaptic a-IGZO TFT with high-k HfLaO gate dielectric as neuromodulator
Authors: Huang An , Ma Yuan Xiao , Li Jia Cheng , Dai De , Yang Hui Xia , Liu Zi Chun , Zhang De Cheng , Yang Han , Huang Yuan , Zhang Yi Yun , Li Xiao Ran , Wang Ye Liang , Lai Pui To
Published: September 2023

In this work, room-temperature-processed amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) have been fabricated with high-k HfLaO as gate dielectric for synaptic devices. By raising the indium content in the a-IGZO film via co-sputtering and treating the HfLaO gate dielectric in an Ar plasma, the TFT with In1.0Ga3.0Zn0.4O2.1 presents excellent electrical characteristics: a high intrinsic carrier mobility of 45.8 cm2 V−1·s−1, a small threshold voltage of 1.93 V, a small hysteresis of −0.015 V, and a small subthreshold swing (SS) of 0.21 V dec−1. Although the oxygen vacancies in the In1.0Ga3.0Zn0.4O2.1 TFT are increased to produce a high carrier mobility, memristive behaviors are hardly observed under zero gate bias due to their occupied states. Various conductance modulations and synaptic plasticities are achieved under a 2-V drain spiking voltage and a small gate bias of 1 V due to migration of oxygen ions and emptying/detrapping of oxygen vacancies in the In1.0Ga3.0Zn0.4O2.1 film, resulting in a concurrent emulation of neurotransmitter and neuromodulator through exploiting the native three-terminal structure of the TFT.
Theoretical analysis of conduction-cooled current lead for superconducting magnet
Authors: Zong Zhanguo , Shimizu Hirotaka
Published: September 2023

CCCL is a typical CL type to energise SC magnets from room to cryogenic temperatures (<100 K) for its simplicity and reliability, but causes a relatively large heat leak (∼50 W kA−1 from 300 K) compared to the heat leak (∼1.0 W kA−1 from 300 K to liquid helium) of VCCLs, which necessitates a comprehensive understanding of designers and users. However, systematic studies on CCCLs are still lacking up to now. This study starts from the differential equation governing heat conduction and generation in CCCLs and firstly derives a completely exact theoretical solution by adopting the WFL law for thermal conductivity and electrical resistivity with temperature dependence. The solution facilitates the CCCL design optimisation to achieve the minimum heat leak, which is determined only by the temperature range but independent of both materials and geometrical parameters. Practical optimum designs are concerned with material properties and approached by calculating a shape factor to determine the conductor length and cross-sectional area, which is detailed and illustrated in this paper. Furthermore, the practical behaviours at low and excess currents can also be mathematically deduced, and the corresponding heat leaks are found to rely on materials but not on geometrical parameters. This paper also describes the agreements between the theoretical analysis and the numerical simulation and comparison with material properties of the non-WFL law.
Thermal and durability characteristics of optimized green concrete developed using slag powder and pond ash
Authors: Maheswaran Jeyaprakash , Chellapandian Maheswaran , Arunachelam Nakarajan , Hari Manikandan Naga Theera
Published: September 2023

Due to the vast development in the infrastructure section, the production of cement-based concrete is a major driving source for the increased global warming and extensive deployment of natural resources such as river sand. To reduce and mitigate these adverse effects, industrial by-products can be effectively used either in partial or complete levels to replace conventional materials such as cement, river sand, etc without compromising the strength and durability characteristics of concrete. This research work focuses on the experimental investigation of the thermal properties, strength, durability and microstructure analysis of optimized green concrete with pond ash and ground granulated blast-furnace slag (GGBS). The novelty of the proposed work lies in the investigation of the thermal and durability characteristics of sustainable green concrete with GGBS and pond ash as a partial replacement for cement and fine aggregate respectively. An optimum mix ratio obtained from the material characterization of 16 trail mixes was tested for mechanical properties, durability and thermal characterization. Moreover, the microstructure analysis of the optimized mix was performed using Scanning Electron Microscope (SEM) to overview the chemical constituents, bonding of molecules at the interfacial transition zone (ITZ), the effect of elevated temperature, etc Results from the trail mixes revealed that the replacement of 30% GGBS and 20% pond ash increased the compressive strength by 8% at 28 days of curing when compared to the control mix. In addition, a detailed multilinear regression analysis was performed and a new equation was proposed to determine the compressive strength of concrete with GGBS and pond ash. The predictions obtained from the proposed equation showed a good match with the benchmark experiments.
Reconciling continuous and discrete models of C4 and CAM evolution
Authors: Edwards Erika J
Published: September 2023

Background

A current argument in the CAM biology literature has focused on the nature of the CAM evolutionary trajectory: whether there is a smooth continuum of phenotypes between plants with C3 and CAM photosynthesis or whether there are discrete steps of phenotypic evolutionary change such as has been modelled for the evolution of C4 photosynthesis. A further implication is that a smooth continuum would increase the evolvability of CAM, whereas discrete changes would make the evolutionary transition from C3 to CAM more difficult.

Scope

In this essay, I attempt to reconcile these two viewpoints, because I think in many ways this is a false dichotomy that is constraining progress in understanding how both CAM and C4 evolved. In reality, the phenotypic space connecting C3 species and strong CAM/C4 species is both a continuum of variably expressed quantitative traits and yet also contains certain combinations of traits that we are able to identify as discrete, recognizable phenotypes. In this sense, the evolutionary mechanics of CAM origination are no different from those of C4 photosynthesis, nor from the evolution of any other complex trait assemblage.

Conclusions

To make progress, we must embrace the concept of discrete phenotypic phases of CAM evolution, because their delineation will force us to articulate what aspects of phenotypic variation we think are significant. There are some current phenotypic gaps that are limiting our ability to build a complete CAM evolutionary model: the first is how a rudimentary CAM biochemical cycle becomes established, and the second is how the ‘accessory’ CAM cycle in C3+CAM plants is recruited into a primary metabolism. The connections to the C3 phenotype we are looking for are potentially found in the behaviour of C3 plants when undergoing physiological stress – behaviour that, strangely enough, remains essentially unexplored in this context.
Artificial intelligence–based opportunistic detection of coronary artery stenosis on aortic computed tomography angiography in emergency department patients with acute chest pain
Authors: Glessgen Carl G , Boulougouri Marianthi , Vallée Jean-Paul , Noble Stéphane , Platon Alexandra , Poletti Pierre-Alexandre , Paul Jean-François , Deux Jean-François
Published: September 2023

Aims

To evaluate a deep-learning model (DLM) for detecting coronary stenoses in emergency room patients with acute chest pain (ACP) explored with electrocardiogram-gated aortic computed tomography angiography (CTA) to rule out aortic dissection.

Methods and results

This retrospective study included 217 emergency room patients (41% female, mean age 67.2 years) presenting with ACP and evaluated by aortic CTA at our institution. Computed tomography angiography was assessed by two readers, who rated the coronary arteries as 1 (no stenosis), 2 (<50% stenosis), or 3 (≥50% stenosis). Computed tomography angiography was categorized as high quality (HQ), if all three main coronary arteries were analysable and low quality (LQ) otherwise. Curvilinear coronary images were rated by a DLM using the same system. Per-patient and per-vessel analyses were conducted. One hundred and twenty-one patients had HQ and 96 LQ CTA. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of the DLM in patients with high-quality image for detecting ≥50% stenoses were 100, 62, 59, 100, and 75% at the patient level and 98, 79, 57, 99, and 84% at the vessel level, respectively. Sensitivity was lower (79%) for detecting ≥50% stenoses at the vessel level in patients with low-quality image. Diagnostic accuracy was 84% in both groups. All 12 patients with acute coronary syndrome (ACS) and stenoses by invasive coronary angiography (ICA) were rated 3 by the DLM.

Conclusion

A DLM demonstrated high NPV for significant coronary artery stenosis in patients with ACP. All patients with ACS and stenoses by ICA were identified by the DLM.
Mechanisms of benefits of sodium-glucose cotransporter 2 inhibitors in heart failure with preserved ejection fraction
Authors: Pandey Arjun K , Bhatt Deepak L , Pandey Avinash , Marx Nikolaus , Cosentino Francesco , Pandey Ambarish , Verma Subodh
Published: September 2023

For decades, heart failure with preserved ejection fraction (HFpEF) proved an elusive entity to treat. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have recently been shown to reduce the composite of heart failure hospitalization or cardiovascular death in patients with HFpEF in the landmark DELIVER and EMPEROR-Preserved trials. While improvements in blood sugar, blood pressure, and attenuation of kidney disease progression all may play some role, preclinical and translational research have identified additional mechanisms of these agents. The SGLT2 inhibitors have intriguingly been shown to induce a nutrient-deprivation and hypoxic-like transcriptional paradigm, with increased ketosis, erythropoietin, and autophagic flux in addition to altering iron homeostasis, which may contribute to improved cardiac energetics and function. These agents also reduce epicardial adipose tissue and alter adipokine signalling, which may play a role in the reductions in inflammation and oxidative stress observed with SGLT2 inhibition. Emerging evidence also indicates that these drugs impact cardiomyocyte ionic homeostasis although whether this is through indirect mechanisms or via direct, off-target effects on other ion channels has yet to be clearly characterized. Finally, SGLT2 inhibitors have been shown to reduce myofilament stiffness as well as extracellular matrix remodelling/fibrosis in the heart, improving diastolic function. The SGLT2 inhibitors have established themselves as robust, disease-modifying therapies and as recent trial results are incorporated into clinical guidelines, will likely become foundational in the therapy of HFpEF.
Predicting pediatric healthcare provider use of virtual reality using a technology acceptance model
Authors: Wang Ellen Y , Kennedy Kristin M , Zhang Lijin , Qian Daniel , Forbes Ty , Zuniga-Hernandez Michelle , Li Brian S-K , Domingue Benjamin , Caruso Thomas J
Published: September 2023

Objective

The primary aim of this study was to apply a novel technology acceptance model (TAM) for virtual reality (VR) in healthcare. The secondary aim was to assess reliability of this model to evaluate factors that predict the intentions of pediatric health providers’ use of VR as an anxiolytic for hospitalized pediatric patients.

Materials and Methods

Healthcare providers that interacted with pediatric patients participated in a VR experience available as anxiolysis for minor procedures and then completed a survey evaluating attitudes, behaviors, and technology factors that influence adoption of new technologies.

Results

Reliability for all domain measurements were good, and all confirmatory factor analysis models demonstrated good fit. Usefulness, ease of use, curiosity, and enjoyment of the VR experience all strongly predict intention to use and purchase VR technologies. Age of providers, past use, and cost of technology did not influence future purchase or use, suggesting that VR technologies may be broadly adopted in the pediatric healthcare setting.

Discussion

Previous VR-TAM models in non-healthcare consumers formulated that age, past use, price willing to pay, and curiosity impacted perceived ease of use. This study established that age, past use, and cost may not influence use in healthcare. Future studies should be directed at evaluating the social influences and facilitating conditions within healthcare that play a larger influence on technology adoption.

Conclusion

The VR-TAM model demonstrated validity and reliability for predicting intent to use VR in a pediatric hospital.
Metastatic site patterns by intrinsic subtype and HER2DX in early HER2-positive breast cancer
Authors: Dieci Maria Vittoria , Conte PierFranco , Bisagni Giancarlo , Bartolini Stefania , Frassoldati Antonio , Generali Daniele , Piacentini Federico , Griguolo Gaia , Tagliafico Enrico , Brasó Maristany Fara , Chic Nuria , Paré Laia , Miglietta Federica , Vicini Roberto , D’Amico Roberto , Balduzzi Sara , Prat Aleix , Guarneri Valentina
Published: September 2023

Background

Even with contemporary treatment strategies, more than 10% of HER2-positive early stage breast cancer patients may experience distant metastasis as first event during follow-up. Tools for predicting unique patterns of metastatic spread are needed to plan personalized surveillance. We evaluated how molecular heterogeneity affects the pattern of distant relapse in HER2-positive breast cancer.

Methods

A total of 677 HER2-positive stage I-III breast cancer patients from ShortHER trial, Cher-LOB trial, and 2 institutional cohorts were included. PAM50 molecular subtypes and research-based HER2DX scores were evaluated. The cumulative incidence of distant relapse as the first event (any site and site specific) was evaluated using competing risk analysis. Median follow-up was 8.4 years. Tests of statistical significance are 2-sided.

Results

Stage III and high HER2DX risk score identified patients at the highest risk of distant relapse as first event (10-year incidence 24.5% and 19.7%, respectively). Intrinsic molecular subtypes were associated with specific patterns of metastatic spread: compared with other subtypes, HER2-enriched tumors were more prone to develop brain metastases (10-year incidence 3.8% vs 0.6%, P = .005), basal-like tumors were associated with an increased risk of lung metastases (10-year incidence 11.1% vs 2.6%, P = .001), and luminal tumors developed more frequently bone-only metastases (10-year incidence 5.1% vs 2.0%, P = .042). When added to stage or HER2DX risk score in competing risk regression models, intrinsic subtype maintained an independent association with site-specific metastases.

Conclusions

The integration of intrinsic molecular subtypes with stage or HER2DX risk score predicts site-specific metastatic risk in HER2-positive breast cancer, with potential implications for personalized surveillance and clinical trials aimed at preventing site-specific recurrence.
Association between a network-based physician linchpin score and cancer patient mortality: a SEER-Medicare analysis
Authors: Moen Erika L , Schmidt Rachel O , Onega Tracy , Brooks Gabriel A , O’Malley A James
Published: September 2023

Background

Patients with cancer frequently require multidisciplinary teams for optimal cancer outcomes. Network analysis can capture relationships among cancer specialists, and we developed a novel physician linchpin score to characterize “linchpin” physicians whose peers have fewer ties to other physicians of the same oncologic specialty. Our study examined whether being treated by a linchpin physician was associated with worse survival.

Methods

In this cross-sectional study, we analyzed Surveillance, Epidemiology, and End Results–Medicare data for patients diagnosed with stage I to III non-small cell lung cancer or colorectal cancer (CRC) in 2016-2017. We assembled patient-sharing networks and calculated linchpin scores for medical oncologists, radiation oncologists, and surgeons. Physicians were considered linchpins if their linchpin score was within the top 15% for their specialty. We used Cox proportional hazards models to examine associations between being treated by a linchpin physician and survival, with a 2-year follow-up period.

Results

The study cohort included 10 081 patients with non-small cell lung cancer and 9036 patients with CRC. Patients with lung cancer treated by a linchpin radiation oncologist had a 17% (95% confidence interval = 1.04 to 1.32) greater hazard of mortality, and similar trends were observed for linchpin medical oncologists. Patients with CRC treated by a linchpin surgeon had a 22% (95% confidence interval = 1.03 to 1.43) greater hazard of mortality.

Conclusions

In an analysis of Medicare beneficiaries with nonmetastatic lung cancer or CRC, those treated by linchpin physicians often experienced worse survival. Efforts to improve outcomes can use network analysis to identify areas with reduced access to multidisciplinary specialists.
Mobile colistin resistance (mcr) genes and recent developments in colistin resistance detection
Authors: Lakshmanan Divya , Ramasamy Dhamodharan , Subramanyam Veni , Saravanan Suresh Kumar
Published: September 2023

The peptide antibiotic colistin has been reserved as a last resort antibiotic treatment option for cases where other antibiotics including carbapenems have failed. Recent emergence of colistin resistance and discovery of mobile colistin resistance (mcr) genes, which encode the cell wall modifying phosphoethanolamine transferase enzyme, complicates the issue. The mcr genes have been associated with conjugative plasmids and can be horizontally transferred between different bacterial species. The global spread of mcr genes has been extensively documented and this warrants surveillance of the resistance genes in the community. However, susceptibility testing of colistin is fraught with practical challenges owing to the chemical nature of the drug and multiple mechanisms of resistance. Although broth microdilution is the current gold standard for colistin susceptibility testing, the method poses technical challenges. Hence, alternative detection methods for screening colistin resistance are the need of the hour. Several methods have been studied in the recent times to address this issue. In this review, we discuss some of the recent developments in the detection of colistin resistance.
The elemental abundance of quiescent galaxies in the LEGA-C survey: the (non-)evolution of [α/Fe] from z = 0.75 to z = 0
Authors: Bevacqua Davide , Saracco Paolo , La Barbera Francesco , D’Ago Giuseppe , De Propris Roberto , Ferreras Ignacio , Gallazzi Anna , Pasquali Anna , Spiniello Chiara
Published: September 2023

We measure the [α/Fe] abundances for 183 quiescent galaxies at z = 0.60−0.75 with stellar masses ranging 10.4 ≤ log10(M*/M⊙) ≤ 11.6 selected from the Large Early Galaxy Astrophysics Census survey. We estimate [α/Fe] from the ratio of the spectral indices Mgb (λ ∼ 5177 Å) and Fe4383, compared to predictions of simple stellar population models. We find that 91 per cent of quiescents in our sample have supersolar [α/Fe], with an average value of [α/Fe] = +0.24 ± 0.01. We find no significant correlation between [α/Fe] and stellar metallicity, mass, velocity dispersion, and average formation time. Galaxies that formed the bulk of their stellar mass on time-scales shorter than 1 Gyr follow the same [α/Fe] distribution as those which formed on longer time-scales. In comparison to local early-type galaxies and to stacked spectra of quiescent galaxies at z = 0.38 and z = 0.07, we find that the average [α/Fe] has not changed between z = 0.75 and the present time. Our work shows that the vast majority of massive quiescent galaxies at z ∼ 0.7 are α-enhanced, and that no detectable evolution of the average [α/Fe] has taken place over the last ∼6.5 Gyr.
ALMA observations of the Extended Green Object G19.01–0.03 – ii. A massive protostar with typical chemical abundances surrounded by four low-mass pre-stellar core candidates
Authors: Williams G M , Cyganowski C J , Brogan C L , Hunter T R , Nazari P , Smith R J
Published: September 2023

We present a study of the physical and chemical properties of the Extended Green Object (EGO) G19.01−0.03 using sub-arcsecond angular resolution Atacama Large Millimetre/submillimetre Array (ALMA) 1.05 mm and Karl G. Jansky Very Large Array (VLA) 1.21 cm data. G19.01−0.03 MM1, the millimetre source associated with the central massive young stellar object (MYSO), appeared isolated and potentially chemically young in previous Submillimetre Array observations. In our ∼0.4 arcsec-resolution ALMA data, MM1 has four low-mass millimetre companions within 0.12 pc, all lacking maser or outflow emission, indicating they may be pre-stellar cores. With a rich ALMA spectrum full of complex organic molecules, MM1 does not appear chemically young, but has molecular abundances typical of high-mass hot cores in the literature. At the 1.05 mm continuum peak of MM1, N(CH3OH) = (2.22 ± 0.01) × 1018 cm−2 and $T_{\mathrm{ex}} = 162.7\substack{+0.3 \\ -0.5}$ K based on pixel-by-pixel Bayesian analysis of LTE synthetic methanol spectra across MM1. Intriguingly, the peak CH3OH Tex = 165.5 ± 0.6 K is offset from MM1’s millimetre continuum peak by 0.22 arcsec ∼ 880 au, and a region of elevated CH3OH Tex coincides with free–free VLA 5.01 cm continuum, adding to the tentative evidence for a possible unresolved high-mass binary in MM1. In our VLA 1.21 cm data, we report the first NH3(3,3) maser detections towards G19.01−0.03, along with candidate 25 GHz CH3OH 5(2, 3) − 5(1, 4) maser emission; both are spatially and kinematically coincident with 44 GHz Class I CH3OH masers in the MM1 outflow. We also report the ALMA detection of candidate 278.3 GHz Class I CH3OH maser emission towards this outflow, strengthening the connection of these three maser types to MYSO outflows.
Resolving the physics of quasar Ly α nebulae (RePhyNe): I. Constraining quasar host halo masses through circumgalactic medium kinematics
Authors: de Beer S , Cantalupo S , Travascio A , Pezzulli G , Galbiati M , Fossati M , Fumagalli M , Lazeyras T , Pensabene A , Theuns T , Wang W
Published: September 2023

Ly α nebulae ubiquitously found around z > 2 quasars can supply unique constraints on the properties of the circumgalactic medium, such as its density distribution, provided the quasar halo mass is known. We present a new method to constrain quasar halo masses based on the line-of-sight velocity dispersion maps of Ly α nebulae. By using MUSE-like mock observations obtained from cosmological hydrodynamic simulations under the assumption of maximal quasar fluorescence, we show that the velocity dispersion radial profiles of Ly α emitting gas are strongly determined by gravity and that they are thus self-similar with respect to halo mass when rescaled by the virial radius. Through simple analytical arguments and by exploiting the kinematics of He ii1640 Å emission for a set of observed nebulae, we show that Ly α radiative transfer effects plausibly do not change the shape of the velocity dispersion profiles but only their normalization without breaking their self-similarity. Taking advantage of these results, we define the variable $\eta ^{140-200}_{40-100}$ as the ratio of the median velocity dispersion in two specifically selected annuli and derive an analytical relation between $\eta ^{140-200}_{40-100}$ and the halo mass which can be directly applied to observations. We apply our method to 37 observed quasar Ly α nebulae at 3 < z < 4.7 and find that their associated quasars are typically hosted by ∼1012.16 ± 0.14M⊙ haloes independent of redshift within the explored range. This measurement, which is completely independent of clustering methods, is consistent with the lowest mass estimates based on quasar autocorrelation clustering at z∼3 and with quasar-galaxies cross-correlation results.
Exploring the evolution of dust temperature using spectral energy distribution fitting in a large photometric survey
Authors: Jones Gareth T , Stanway Elizabeth R
Published: September 2023

Panchromatic analysis of galaxy spectral energy distributions, spanning from the ultraviolet to the far-infrared, probes not only the stellar population but also the properties of interstellar dust through its extinction and long-wavelength re-emission. However, little work has exploited the full power of such fitting to constrain the redshift evolution of dust temperature in galaxies. To do so, we simultaneously fit ultraviolet, optical, and infrared observations of stacked galaxy subsamples at a range of stellar masses and photometric redshifts at 0 < z < 5, using an energy-balance formalism. However, we find UV-emission beyond the Lyman limit in some photometric redshift selected galaxy subsamples, giving rise to the possibility of contaminated observations. We carefully define a robust clean subsample which extends to no further than z ∼ 2. This has consistently lower derived temperatures by $4.0^{+5.0}_{-1.9}$ K, relative to the full sample. We find a linear increase in dust temperature with redshift, with Td (z) = (4.8 ± 1.5) × z + (26.2 ± 1.5) K. Our inferred temperature evolution is consistent with a modest rise in dust temperature with redshift, but inconsistent with some previous analyses. We also find a majority of photometrically selected subsamples at z > 4.5 underpredict the IR emission while giving reasonable fits to the UV-optical. This could be due to a spatial disconnect in the locations of the UV and IR emission peaks, suggesting that an energy-balance formalism may not always be applicable in the distant Universe.
Ultraluminous quasars at high redshift show evolution in their radio-loudness fraction in both redshift and ultraviolet luminosity
Authors: Lah Philip , Onken Christopher A , Norris Ray P , D’Eugenio Francesco
Published: September 2023

We take a sample of 94 ultraluminous, optical quasars from the search of over 14 486 deg2 by Onken et al. in the range 4.4 < redshift < 5.2 and match them against the Rapid ASKAP Continuum Survey (RACS) observed on the Australian Square Kilometre Array Pathfinder (ASKAP). From this most complete sample of the bright end of the redshift ∼5 quasar luminosity function, there are 10 radio continuum detections, of which eight are considered radio-loud quasars. The radio-loud fraction for this sample is 8.5 ± 2.9 per cent. Jiang et al. found that there is a decrease in the radio-loud fraction of quasars with increasing redshift and an increase with increasing absolute magnitude at rest frame 2500 Å. We show that the radio-loud fraction of our quasar sample is consistent with that predicted by Jiang et al.,extending their result to higher redshifts.
Buoyancy response of a disc to an embedded planet: a cross-code comparison at high resolution
Authors: Ziampras Alexandros , Paardekooper Sijme-Jan , Nelson Richard P
Published: September 2023

In radiatively inefficient, laminar protoplanetary discs, embedded planets can excite a buoyancy response as gas gets deflected vertically near the planet. This results in vertical oscillations that drive a vortensity growth in the planet’s corotating region, speeding up inward migration in the type-I regime. We present a comparison between pluto/idefix and fargo3D using 3D, inviscid, adiabatic numerical simulations of planet–disc interaction that feature the buoyancy response of the disc, and show that pluto/idefix struggle to resolve higher-order modes of the buoyancy-related oscillations, weakening vortensity growth, and the associated torque. We interpret this as a drawback of total-energy-conserving finite-volume schemes. Our results indicate that a very high resolution or high-order scheme is required in shock-capturing codes in order to adequately capture this effect.
Complexity of Infectious Diseases Compared With Other Medical Subspecialties
Authors: Grundy Brian , Houpt Eric
Published: September 2023

We aimed to highlight the complexity of the field of clinical infectious diseases compared with other medical specialties. Using available metrics, the body of knowledge within clinical infectious diseases is comparatively large and complex. This increasing complexity is underappreciated by current physician compensation schemes, needs to be carefully managed to educate future physicians, and may serve as a barrier to recruitment into the field.
Classifying MaNGA velocity dispersion profiles by machine learning
Authors: Duann Yi , Tian Yong , Ko Chung-Ming
Published: September 2023

We present a machine-learning (ML) approach for classifying kinematic profiles of elliptical galaxies in the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. Previous studies employing ML to classify spectral data of galaxies have provided valuable insights into morphological galaxy classification. This study aims to enhance the understanding of galaxy kinematics by leveraging ML. The kinematics of 2624 MaNGA elliptical galaxies are investigated using integral field spectroscopy by classifying their one-dimensional velocity dispersion (VD) profiles. We utilized a total of 1266 MaNGA VD profiles and employed a combination of unsupervised and supervised learning techniques. The unsupervised K-means algorithm classifies VD profiles into four categories: flat, decline, ascend, and irregular. A bagged decision trees classifier (TreeBagger)-supervised ensemble is trained using visual tags, achieving 100 ${{\ \rm per\ cent}}$ accuracy on the training set and 88 ${{\ \rm per\ cent}}$ accuracy on the test set. Our analysis identifies the majority (68 ${{\ \rm per\ cent}}$) of MaNGA elliptical galaxies presenting flat VD profiles, which requires further investigation into the implications of the dark matter problem.
Contribution of Health Care Practitioner and Maternity Services Factors to Racial Disparities in Alabama
Authors: Toluhi Angelina A. , Richardson Molly R. , Julian Zoe I. , Sinkey Rachel G. , Knight Candace C. , Budhwani Henna , Szychowski Jeff M. , Wingate Martha S. , Tita Alan T. , Baskin Monica L. , Turan Janet M.
Published: September 2023

OBJECTIVE:

Black patients are three times more likely to die of pregnancy-related causes than White patients in the United States, and Alabama has the third worst maternal mortality rate in the nation. We sought to identify health care practitioner and maternity service factors contributing to disparities in Alabama, as well as potential strategies to address these contributors.

METHODS:

We conducted key informant interviews with obstetricians, nurses, doulas, lactation counselors, health system administrators, and representatives of professional organizations who deliver maternity care to racially and ethnically diverse patients in Alabama. The interview guide was developed using Howell's conceptual framework on racial and ethnic disparities in severe maternal morbidity and mortality. Adopting a thematic analysis approach, we coded and analyzed transcripts using NVivo 12 software. Open coding and selective coding were conducted to identify themes related to health care practitioner– and maternity services–level determinants.

RESULTS:

Overall, 20 health care practitioners or administrators were interviewed. Primary themes related to health care practitioners included implicit bias and explicit racism, lack of communication and lack of positive patient–health care practitioner relationships, lack of cultural sensitivity, and variation in clinical knowledge and experience. Primary themes related to maternity services included lack of accessibility, inadequate quality and content of care, lack of continuity of care, discriminatory facility policies, and workforce shortages and lack of diversity. Strategies suggested by participants to address these factors included bias trainings for health care practitioners, improvements in racial and interdisciplinary diversity in the maternity workforce, and evidence-based interventions such as group prenatal care, disparities dashboards, simulation trainings, early warning signs criteria, and coordinated care.

CONCLUSION:

We gained diverse perspectives from health care practitioners and administrators on how maternity health care practitioner and maternity health services factors contribute to inequities in maternal health in Alabama. Strategies to address these contributing factors were multifaceted.
Advancing Equity in U.S. Hospital Systems: Employee Understandings of Health Equity and Steps for Improvement
Authors: Uehling Melissa , Hall-Clifford Rachel , Kinnard Crystal , Wimberly Yolanda
Published: September 2023

Goals:

Equity in the U.S. healthcare system remains a vital goal for healthcare leaders. Although many hospitals and healthcare systems have adopted a social determinants of health approach to more equitable care, many challenges have limited the effectiveness of their efforts. In this study, we wanted to explore whether healthcare leaders and providers understand the concept of equity and can link the concepts to practical applications within healthcare systems.

Methods:

We explored how hospital leadership and providers at a major public hospital in Atlanta, Georgia, understand equity topics both conceptually and at a practical implementation level. We conducted 28 focus groups for >4 months involving 233 staff members, during which participants were asked about their understanding of various equity-related terms and equity implementation within the hospital.

Principal Findings:

Our findings reveal that there is little consensus among staff regarding the conceptual meanings of various health equity–related terms, and only a small minority of staff can articulate a conceptual definition that reflects current research-based understandings of equity. Furthermore, there is little consensus regarding how staff believes that health equity is practically enacted through various hospital programs, even among interviewees who could correctly articulate equity topics. These findings have no association with a role in the organization or length of time employed at the hospital.

Practical Applications:

These findings indicate a need for a more nuanced understanding of health equity and further clarification and education on how to implement health equity. Although understanding at the conceptual level is an important first step, conceptual knowledge alone is not enough to support health equity at either the individual staff level or the system level. Our recommendations cover strategic development; education specific to the hospital system and its unique needs; consideration of the specific roles of individuals in the organization; and the designation of diversity, equity, and inclusion staff and offices in a hospital organization.
Development and validation of a novel nomogram to predict postoperative pancreatic fistula after pancreatoduodenectomy using Lasso-logistic regression: an international multi-institutional observational study
Authors: Gu Zongting , Du Yongxing , Wang Peng , Zheng Xiaohao , He Jin , Wang Chengfeng , Zhang Jianwei
Published: September 2023

Background:

Existing prediction models for clinically relevant postoperative pancreatic fistula after pancreatoduodenectomy lack discriminatory power or are too complex. This study aimed to develop a simple nomogram that could accurately predict clinically relevant postoperative pancreatic fistula after pancreatoduodenectomy.

Methods:

A high-volume, multicenter cohort of patients who underwent pancreatoduodenectomy from the American College of Surgeons-National Surgical Quality Improvement Program database in the United States during 2014-2017 was used as the model training cohort (n=3609), and patients who underwent pancreatoduodenectomy from the Pancreatic Center of National Cancer Center Hospital in ***** during 2014-2019 were used as the external validation cohort (n=1347). The study used lasso penalized regression to screen large-scale variables, then logistic regression was performed to screen the variables and build a model. Finally, a prediction nomogram for clinically relevant postoperative pancreatic fistula was established based on the logistic model, and polynomial equations were extracted. The performance of the nomogram was evaluated by receiver operating characteristic curve, calibration curve, and decision curve analysis.

Results:

In the training and validation cohorts, there were 16.7% (601/3609) and 16.6% (224/1347) of patients who developed clinically relevant postoperative pancreatic fistula, respectively. After screening using Lasso and logistic regression, only 6 predictors were independently associated with clinically relevant postoperative pancreatic fistula, including 2 preoperative indicators (weight and pancreatic duct size), 1 intraoperative indicator (pancreatic texture), and 3 postoperative indicators (deep surgical site infection, delayed gastric emptying, and pathology). The prediction of the new nomogram was accurate, with an area under the curve of 0.855 (95% CI, 0.702-0.853) in the external validation cohort, and the predictive performance was superior to three previously proposed postoperative pancreatic fistula risk score models (all P<0.001, likelihood ratio test).

Conclusions:

A reliable Lasso-logistic method was applied to establish a novel nomogram based on 6 readily available indicators, achieving a sustained, dynamic, and precise postoperative pancreatic fistula prediction for pancreatoduodenectomy patients. With a limited number of variables and easy clinical application, this new model will enable surgeons to proactively predict, identify and manage pancreatic fistulas to obtain better outcomes from this daunting postoperative complication.
Incidence of Cirrhosis and Hepatocellular Carcinoma Among Veterans With Noncirrhotic Metabolic Dysfunction-associated Fatty Liver Disease
Authors: Yeoh Aaron , Yang Zeyuan , Cheung Ramsey , Do Albert , Ahmed Aijaz , Wong Robert J.
Published: September 2023

Background and Aims:

Despite the high prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD), the long-term incidence of cirrhosis or hepatocellular carcinoma (HCC) among adults with MAFLD is not well described. Using a national cohort of United States Veterans, we evaluated the overall incidence and predictors of cirrhosis and HCC among adults with noncirrhotic MAFLD.

Methods:

Data from the 2010 to 2022 Veterans Affairs database were used to identify adults with noncirrhotic MAFLD using established definitions. Five and 10-year incidence of cirrhosis and HCC were assessed and stratified by demographics and relevant clinical variables. Multivariate Cox proportional hazard models were utilized to determine predictors of cirrhosis and HCC.

Results:

Among 969,253 patients with noncirrhotic MAFLD (94.5% males, 70.2% non-Hispanic white, mean age of 62.7 ± 12.2 y), the 10-year incidence of cirrhosis and HCC was 3.70% (95% CI: 3.66-3.74) and 0.69% (95% CI: 0.67-0.70), respectively. When stratified by race/ethnicity, the 10-year incidence of cirrhosis was lowest among Asians (2.63%, 95% CI: 2.37-2.88) and highest among Hispanics (4.60%, 95% CI: 4.45-4.75), a pattern also observed with HCC. Significant disparities in risk of cirrhosis or HCC were observed when stratified by sex, substance use, and comorbidities. Risks of cirrhosis and HCC were highest in patients with baseline fibrosis-4 >2.67.

Conclusion:

This large study provides important epidemiological data describing the natural history of adults with MAFLD. Disparities in risk of cirrhosis and HCC were observed by demographic and clinical characteristics, emphasizing the importance of early identification of MAFLD with modifiable high-risk features to implement earlier interventions to improve long-term outcomes.
Nipple-Preserving Inferior-Ellipse Mastectomy: A New Technique for Gender-Affirming Top Surgery
Authors: Robinson Isabel S. , Salibian Ara , Zhao Lee C. , Bluebond-Langner Rachel
Published: September 2023

The 2 most common techniques for gender-affirming mastectomy are the double-incision free nipple graft and periareolar techniques. However, some patients are not well suited for either technique. When the nipples are high and on the pectoralis muscle, but there is marked breast tissue and skin redundancy, a double-incision free nipple graft would land the incision above the pectoral shadow, but a periareolar approach would not adequately remove the excess skin. In these patients, a nipple-preserving inferior-ellipse incision allows for appropriate chest contouring, leaving the nipple position unchanged and placing the incision in the pectoralis muscle shadow. A retrospective review identified all consecutive patients undergoing nipple-preserving inferior-ellipse mastectomy by the senior author (R.B.-L.). Indications were patients with moderate glandular tissue, skin excess, and a high nipple-areola complex (NAC) above the inferior border of the pectoralis major. Sixteen patients underwent inferior-ellipse mastectomy and were included. Mean follow-up was 203 days. Two patients (14%) required revision of the NAC. There was no partial or complete NAC loss. One patient (7%) developed postoperative seroma, which resolved with aspiration. For patients with moderate glandular tissue, excess skin in the inferior pole, and NAC position above the inferior border of the pectoralis major, the nipple-preserving inferior-ellipse mastectomy technique achieves excellent chest contour.