bluuebunny/crossref_metadata_2025 huggingface dataset:
Observable and ionizing properties of star-forming galaxies with very massive stars and different initial mass functions
Authors: Schaerer D. , Guibert J. , Marques-Chaves R. , Martins F.
Published: December 2024

Context. The presence of very massive stars (VMS) with masses > 100 M⊙ is now firmly established in the Local Group, nearby galaxies, and out to cosmological distances. If present, these stars could boost the UV luminosity and ionizing photon production of galaxies, helping to alleviate the overabundance of UV-bright galaxies found with JWST at high redshift.

Aims. To examine these questions, we quantify the impact of VMS on properties of integrated stellar populations, exploring different stellar initial mass functions (IMFs) extending up to 400 M⊙, and with slopes between standard (Salpeter-like) and flatter, more top-heavy IMFs.

Methods. Combing consistent stellar evolution and atmosphere models tailored to VMS at 1/2.5 Z⊙ metallicity with BPASS evolutionary synthesis models and including nebular emission, we computed integrated spectral energy distributions (SEDs) and derived quantities for a large set of models.

Results. We find that VMS contribute significantly to the UV luminosity and Lyman continuum emission of young stellar populations, and they are characterized by strong stellar He II emission, with EW(He IIλ1640) up to 4–8 Å at young ages or ∼2.5 − 4 Å for a constant star formation rate (SFR) (for the IMFs considered here). For IMFs with a Salpeter slope, the boost of the UV luminosity is relatively modest (up to a factor of ∼1.6). However, small changes in the IMF slope (e.g., from α2 = −2.35 to −2) lead to large increases in LUV and the ionizing photon production, Q. The ionizing photon efficiency, ξion, is also increased with VMS, by typically 0.14–0.2 dex for a Salpeter slope, and by up to ∼0.4 dex when the IMF is extended up to 400 M⊙. Stronger H recombination lines are also predicted in the presence of VMS. Interestingly, SEDs including VMS show smaller Lyman breaks, and the shape of the ionizing spectra remain essentially unaltered up to ∼35 eV, but become softer at higher energies. We derive and discuss the maximum values that quantities such as LUV per stellar mass or unit SFR, ξion, Q, and others can reach when VMS are included, and we show that these values become essentially independent of the IMF. We propose observational methods to test for the presence of VMS and constrain the IMF in star-forming galaxies. Finally, using published JWST observations, we examine if high redshift (z ≳ 5 − 6) galaxies show some evidence of the presence of VMS and/or signs of non-standard IMFs. Very top-heavy IMFs can be excluded on average, but we find that the IMF could well extend into the regime of VMS and be flatter than Salpeter in the bulk of high-z galaxies.

Conclusions. The predictions should improve our understanding of the stellar content and IMF of the most distant galaxies and allow us to establish if “extreme” or “unusual” populations extending well beyond 100 M⊙ existed in the early Universe.
The ESO SupJup Survey. IV. Unveiling the carbon isotope ratio of GQ Lup B and its host star
Authors: González Picos D. , Snellen I.A.G. , de Regt S. , Landman R. , Zhang Y. , Gandhi S. , Sánchez-López A.
Published: December 2024

The carbon isotope ratio ( ) is a potential tracer of giant planet and brown dwarf formation. The GQ Lup system, which hosts the K7 T Tauri star GQ Lup A and its substellar companion GQ Lup B, provides a unique opportunity to investigate in a young system. We aim to characterise GQ Lup B’s atmosphere, determining its temperature, chemical composition, spin, surface gravity, and while also measuring the of its host star, GQ Lup A. We obtained high-resolution K -band spectra of GQ Lup using CRIRES^+ at the VLT. We modelled GQ Lup A’s starlight contribution and fitted GQ Lup B's spectrum using atmospheric models from petitRADTRANS . The of GQ Lup A was derived using isotope-dependent PHOENIX models. We measured atmospheric abundances in GQ Lup B, including HF, Na, Ca, and Ti, and determined a C/O ratio of $0.50 ± 0.01$, which is consistent with the solar value. The carbon isotope ratio is $ for GQ Lup B and $51^ $ for GQ Lup A. Strong veiling of GQ Lup A’s photospheric lines was also identified and accounted for. The similar values in GQ Lup A and B suggest a common origin from a shared material reservoir, supporting the idea of formation via disc fragmentation or gravitational collapse.
Relationship between prenatal ultrasound signs and genetic abnormalities for fetal malformations of cortical development
Authors: Chen JunYa , Zhu Rong , Pan Hong , Ma YiNan , Zhu Ying , Liu LiLi , Hou XinLin , Haratz Karina Krajden
Published: December 2024

To explore the relationship between ultrasound signs of suspected fetal malformation of cortical development (MCD) and genetic MCD.

The retrospective study involved fetuses with one of the following 10 neurosonography (NSG) signs: (A) abnormal development of the Sylvian fissure; (B) delayed achievement of cortical milestones; (C) premature or aberrant appearance of sulcation; (D) irregular border of the ventricular wall or irregular shape of the ventricle; (E) abnormal shape or orientation of the sulci; (F) hemispheric asymmetry; (G) non-continuous cerebral cortex; (H) intraparenchymal echogenic nodules; (I) persistent ganglionic eminence (GE) or GE cavitation; (J) abnormal cortical lamination.

95 fetuses were included in the study. Chromosomal microarray (CMA) combined with exome sequencing (ES) was available in 40 fetuses, CMA was abnormal in nine and ES in 22. Sign C (7/7, 100%), sign H (2/2, 100%), sign A (18/19, 94.7%), and sign B (12/13, 92.3%) were the signs leading to the highest probability of genetic MCD. The incidence of genetic MCD for sign E, sign I, and sign D was 66.7–73.7%. Only one or none of the fetuses with sign J, sign F, or sign G underwent CMA+ES. The signs in the fetuses with FGFR3, CCND2, FLNA, or TSC2 mutations had the expected features. The other fetuses with different gene mutations showed several non-specific NSG signs.

Several reliable signs for genetic MCD can be detected by NSG, and the probability varies with different signs. Most signs are not associated with a specific gene. Therefore, CMA combined with ES is preferred.
Intercostal Nerve Cryoablation as an Effective Pain Management Strategy in the Nuss Procedure: Reducing Opioid Use and Hospital Stay
Authors: Santana Lisgelia , Abels Mario , Driggers John , Carvalho Norman
Published: December 2024

Introduction Erector spinae plane (ESP) blocks, thoracic epidural, and patient-controlled analgesia (PCA) have all been used for perioperative pain management in the Nuss procedure without a consensus on what modality produces the best outcomes. Intercostal nerve cryoablation (INC) is a relatively new modality that involves freezing the nerves to prevent pain during recovery. Our hypothesis is that using INC for the Nuss procedure will decrease opioid use, pain scores, and length of stay (LOS) but will increase cost compared with ESP block, thoracic epidural, and PCA.

Materials and Methods This retrospective, observational study compared 108 patients who underwent the Nuss procedure at a pediatric acute care children's hospital in the southeast US. Patient charts were evaluated for significant differences in LOS, opioid use, and reported pain ratings based on type of analgesia administered: INC (n = 30), ESP block (n = 19), thoracic epidural (n = 41), and PCA (n = 18). Secondary variables included emergency department visits, readmissions, opioid refills, and various anesthetic and operative costs. Analysis of variance was performed on all outcome measures.

Results Average LOS was significantly decreased in the INC group (2.9 days) compared with the thoracic epidural (4.7 days, p < 0.05) and the PCA groups (3.7 days, p < 0.05). Average cumulative opioid use was significantly decreased in the INC group (50.4 morphine milligram equivalents [MME]) compared with the thoracic epidural (117 MME, p < 0.05) and PCA groups (172.1 MME, p < 0.05).

Conclusions This study suggests that INC can be a viable and cost-effective option for reducing postoperative opioid consumption and LOS in Nuss procedure patients. Pain perception was lower in the INC group compared with the rest of the groups, except the epidurals, which were similar. However, the opioid consumption of the INC group was significantly lower than any other group. Despite the INC group having higher initial costs, it did not result in the highest total hospital charges, indicating its potential cost-effectiveness. There is a need for larger prospective randomized controlled trials to guide future research efforts.
Prophylactic clip closure in preventing delayed bleeding after colorectal endoscopic submucosal dissection in patients on anticoagulants: a multicenter retrospective cohort study in Japan
Authors: Takada Kazunori , Yoshida Naohisa , Hayashi Yoshikazu , Togo Daichi , Oka Shiro , Fukunaga Shusei , Morita Yoshinori , Hayashi Takemasa , Kozuka Kazuhiro , Tsuji Yosuke , Murakami Takashi , Yamamura Takeshi , Komeda Yoriaki , Takeuchi Yoji , Shinmura Kensuke , Fukuda Hiroko , Yoshii Shinji , Ono Shoko , Katsuki Shinichi , Kawashima Kazumasa , Nemoto Daiki , Yamamoto Hiroyuki , Saito Yutaka , Tamai Naoto , Tamura Aya ,   on behalf of the ABCD-J Working Group
Published: December 2024

Background The effectiveness of prophylactic clip closure in reducing the risk of delayed bleeding after colorectal endoscopic submucosal dissection (ESD) is uncertain among patients on anticoagulants. We therefore aimed to assess this effectiveness using data from a large multicenter study.

Methods We used the ABCD-J study database to analyze delayed bleeding among 34 455 colorectal ESD cases from 47 Japanese institutions. Delayed bleeding rates among the no/partial and complete closure groups were compared in patients on direct oral anticoagulants (DOACs) or warfarin. Propensity score matching was used for baseline characteristics to reduce the effects of selection bias.

Results Overall, data from 1478 patients on anticoagulants who underwent colorectal ESD were examined. After propensity score matching, the complete and no/partial closure groups were compared in 212 patients on DOACs and 82 on warfarin. The complete closure group showed a significantly lower delayed bleeding rate in patients receiving DOACs (10.8 % vs. 5.2 %, absolute risk reduction [ARR] 5.7 %, P = 0.048) and warfarin (17.1 % vs. 6.1 %, ARR 11.0 %, P = 0.049). Additionally, complete closure significantly reduced the risk of delayed bleeding among patients taking DOACs for right-sided lesions (ARR 6.7 %, P = 0.04), whereas no risk reduction was observed for left-sided (P > 0.99) or rectal (P = 0.50) lesions. A similar trend was observed among patients on warfarin.

Conclusions Prophylactic complete clip closure after colorectal ESD significantly reduced the delayed bleeding rate in patients receiving DOACs or warfarin. It should be performed after ESD, particularly for right-sided lesions.
A Clinical Decision Support System for Addressing Health-Related Social Needs in Emergency Department: Defining End User Needs and Preferences
Authors: Mazurenko Olena , Hirsh Adam T. , Harle Christopher A. , McNamee Cassidy , Vest Joshua R.
Published: December 2024

Background Health-related social needs (HRSNs) are the unmet social and economic needs (e.g., housing instability) that affect individuals' health and well-being. HRSNs are associated with more emergency department (ED) visits, longer stays, and worse health outcomes. More than a third of ED patients have at least one HRSN, yet patients are rarely screened for HRSNs in the ED. A clinical decision support (CDS) system with predictive modeling offers a promising approach to identifying patients systematically and efficiently with HRSNs in the ED.

Objective This study aimed to identify ED clinician and staff preferences for designing and implementing an HRSN-related CDS system.

Methods A multistep, user-centered design study involving qualitative semistructured interviews, observations of ED workflows, and a multidisciplinary design workshop.

Results We conducted 16 semistructured interviews with ED clinicians and staff. Following the interviews, three research team members observed ED workflows, focusing on patient entry and clinician and staff usage of the electronic health record (EHR) system. Finally, we conducted a 3-hour multidisciplinary design workshop. An HRSN-related CDS system should be visually appealing, color-coordinated, and easily accessible in the EHR. An HRSN-related CDS system should target a select group of ED patients (to be discharged from the ED) and highlight a select set of critical HRSN issues early in the workflow to adjust clinical care adequately. An HRSN-related CDS system should provide a list of actions and the ability to notify the clinical team if the patient's HRSNs were addressed.

Conclusion The user-centered design identified a set of specific preferences for an HRSN-related CDS system to be implemented in the ED. Future work will focus on implementing and refining the CDS system and assessing the rates of changes in clinical care (e.g., rates of referrals) to address patient HRSNs in the ED.
Adolescents’ experiences and (re)action towards fake news on social media: perspectives from Norway
Authors: Selnes Florence Namasinga
Published: December 2024

The majority of adolescents encounter unverifiable news as they navigate social media in their daily lives. A survey in Norway where this study is situated found that two out of three teenagers had come across content that they suspected to be fake, and that the teens considered themselves highly competent in distinguishing between credible and fake news. This study draws on teens’ narratives and perspectives as articulated through focus groups and interviews to explore their experiences as well as awareness of how to deal with fake news when they encounter on social media. The study reveals awareness of diffusion of fake news and knowledge of tactics that are important for evaluating online. Specifically, participants regard ignoring; multiple news verification tactics and using social media delete, block, flag and report functions as important for managing fake news. The paper argues that ignoring can be an effective tactic for reducing the diffusion of fake news on social media and should be adopted and incorporated in news media literacy programs. Otherwise, it can lead to disengagement from and passivity towards news.
Finding bifurcations in mathematical epidemiology via reaction network methods
Authors: Vassena N. , Avram F. , Adenane R.
Published: December 2024

Mathematical Epidemiology (ME) shares with Chemical Reaction Network Theory (CRNT) the basic mathematical structure of its dynamical systems. Despite this central similarity, methods from CRNT have been seldom applied to solving problems in ME. We explore here the applicability of CRNT methods to find bifurcations at endemic equilibria of ME models.
Electrical and structural analysis of GaN/ZnO/Ga2O3 bonded interfaces; observation of spinel ZnGa2O4 after annealing
Authors: Kosanovic Stefan , Sun Kai , Jian Ashley , Zhai Xin , Mishra Umesh , Ahmadi Elaheh
Published: December 2024

The process of wafer bonding β-Ga2O3 and N-polar GaN with a ZnO “glue layer” was optimized to reduce resistance at the bonded interface. The GaN/ZnO and Ga2O3/ZnO interfaces were studied using TEM, with a focus on the effect of annealing on the ZnO. The thickness of the ZnO “glue layer” was studied to find the optimal behavior and minimum resistance at the interface, with 5 nm determined to give ohmic behavior with resistance lower than the measurement setup could characterize. TEM analysis revealed that the GaN/ZnO interface was sharp before and after annealing, whereas the Ga2O3/ZnO sample had a ZnGa2O4 interlayer that crystallized upon annealing, matching its crystal orientation to the substrate.
Analog control of La0.5Sr0.5FeO3-δ electrical properties through oxygen deficiency induced magnetic transition
Authors: Nizet Paul , Chiabrera Francesco , López-Pintó Nicolau , Alayo Nerea , Langner Philipp , Valencia Sergio , Fraile Rodríguez Arantxa , Baiutti Federico , Smekhova Alevtina , Morata Alex , Sort Jordi , Tarancón Albert
Published: December 2024

Switchability of materials properties by applying controlled stimuli such as voltage pulses is an emerging field of study with applicability in adaptive and programmable devices like neuromorphic transistors or non-emissive smart displays. One of the most exciting approaches to modulate materials performance is mobile ion/vacancy insertion for inducing changes in relevant electrical, optical, or magnetic properties, among others. Unveiling the interplay between changes in the concentration of mobile defects (like oxygen vacancies) and functional properties in relevant materials represents a step forward for underpinning the emerging oxide iontronics discipline. In this work, electrochemical oxide-ion solid-state pumping cells were fabricated for analog control of the oxygen stoichiometry in thin films of mixed ionic-electronic conductor La0.5Sr0.5FeO3-δ. We demonstrate over more than four orders of magnitude electronic conductivity control at 50 °C within the same crystallographic phase through precise and continuous voltage control of the oxygen stoichiometry. We show that behind the modification of the transport properties of the material lays a paramagnetic-to-antiferromagnetic transition. We exploit such magnetoelectric coupling to show control over the exchange interaction between La0.5Sr0.5FeO3-δ and a ferromagnetic Co layer deposited on top.
Effects of zero and reversed magnetic shear on resistive wall modes in a straight limiter tokamak with zero beta
Authors: Wan Sui , Zhu Ping , Li Haolong
Published: December 2024

Advanced tokamak scenarios often feature equilibriums with zero and reversed magnetic shear. To isolate and investigate their impacts on the resistive wall mode (RWM) instability analytically, we construct a series of cylindrical limiter equilibriums with different magnetic shear in the core and toward plasma edge, as a prototype of the configurations in advanced tokamak scenarios. Equilibriums with zero β are considered so that the analysis focuses on the current-driven RWMs. Analytical solutions for the n=1 resistive wall mode, derived from the reduced ideal magnetohydrodynamics (MHD) equations, consistently demonstrate key insights for both the core and the edge: the growth rate of RWMs is inversely proportional to the averaged magnetic shear when the safety factor at the edge (qa) is held constant. Specifically, an increase in positive averaged magnetic shear results in a decreased growth rate, whereas an increase in negative averaged magnetic shear leads to an increased growth rate. Furthermore, the influence of nqa on the mode's stability significantly surpasses the effects of magnetic shear changes previously discussed. These analytical calculation results provide a verification of NIMROD simulations.
Numerical simulation of flow-induced vibration of a cylinder near a finite-length plate
Authors: Shishaeva Anastasia , Ivanov Oleg
Published: December 2024

Vortex-induced vibrations of an elastically mounted rigid cylinder in a gas flow near a finite-length plate were numerically studied. The mass ratio was equal to 1187.5, and the Reynolds number was varied from 192 to 384. The direct numerical simulation was performed in a two-dimensional approach in computational fluid dynamics code FlowVision by using Navier–Stokes equations for a gas flow and solid body motion equation for a vibrating cylinder. Different positions of the cylinder relative to the plate along and across the flow were investigated. It was obtained that the gap between the cylinder and the plate surface has the main effect on the oscillation if the gap is less than one diameter of the cylinder. Meanwhile, the streamwise distance between the plate trailing edge and the cylinder center affects the oscillation only if the gap is smaller than 0.167 of the diameter of the cylinder. In both cases, a lock-in was shifted to the higher range of speeds.
Equation of State for Solid Argon Valid for Temperatures up to 300 K and Pressures up to 16 GPa
Authors: Maltby Tage W. , Hammer Morten , Wilhelmsen Øivind
Published: December 2024

A new equation of state (EoS) is presented for solid argon. The EoS is based on the quasi-harmonic approximation and formulated in terms of the Helmholtz energy, with temperature and molar volume as independent variables. To ensure high accuracy over a wide range of pressures, the static energy is represented semi-analytically by a Buckingham potential with three-body corrections. The vibrational modes are represented by Debye and Einstein contributions, and the EoS includes an anharmonic correction. A comprehensive collection of available experimental data has been used in the parameter optimization, including pressure and volume measurements along the co-existence curves, heat capacities, thermal expansivities and isothermal compressibilites. The EoS reproduces the molar volumes along the sublimation coexistence curve within an estimated uncertainty of 0.03%. For the heat capacity, the uncertainty is estimated to 1% in the range 20–50 K, 2% at higher temperatures, and 6% at lower temperatures. The isentropic and isothermal compressibilities have estimated uncertainties of 4% and 3%. For the thermal expansivity, the EoS has an estimated uncertainty of 2% above, and 5% below 30 K. For the pressure along the phase coexistence curves, the EoS has an estimated uncertainty of 0.4% for melting and 5% for sublimation. For the calculation of pressure as function of temperature and molar volume, the average relative deviation with respect to all available data is 5%. The EoS is valid up to pressures of 16 GPa and temperatures of 300 K, yet extrapolates well at temperatures beyond this range. The EoS represents the coexistence of solid argon in argon–hydrogen and argon–helium fluid mixtures nearly within the experimental uncertainty, provided that the EoS used to represent the fluid phase is sufficiently accurate.
Polymer scission and molecular weight prediction in continuous abrupt contraction–expansion microchannel
Authors: Yin Guangzhou , Nakamura Yuta , Suzuki Hiroshi , Lequeux François , Hidema Ruri
Published: December 2024

This study conducted a two-dimensional numerical simulation of flow in continuous abrupt contraction–expansion microchannel, using experimental measurements as input parameters to validate the reliability of the simulation by comparing the experimental and simulated flow regimes. Memory effects and polymer scission altered flow regime and decrease the elasticity of the solution. Consequently, the relaxation time and maximum extensibility parameter were continuously adjusted in the simulation to match the flow regime in each cavity, successfully predicting the polymer solution's molecular weight after each instance of scission for the first time. The simulation also provided distributions of velocity, extensional rate, and the first normal stress difference, clarifying the mechanism of continuous polymer chain scission during flow. The results suggest that scission likely occurs near the contraction region and the corners between the throat and expansion sections. Along the channel, velocity gradients and extensional rates near the contraction region increase, while first normal stress difference decreases, indicating that chain scission reduces solution elasticity, lowers flow resistance, and increases extensional rates, promoting further chain scission.
An unsteady Cartesian grid based two-dimensional plus time method for simulating motion responses of high-speed vessels
Authors: Zhang Yifan , Zhang Yunxing , Ma Shan , Shao Wenbo , Huang Xin
Published: December 2024

Currently, the hydrodynamic simulation strategies for high-speed vessels exhibit a wide diversity. Direct three-dimensional (3D) Computational Fluid Dynamics simulation would be the most suitable choice if not for its time-consuming nature. To save computational resources and accelerate calculation speed, research works that utilize two-dimensional (2D) approaches to address three-dimensional problems have emerged over the past few decades, which represented by strip theory and two-dimensional plus time (2D+t) theory. Among them, Cartesian grid-based 2D+t method could be the most accurate one. However, this method, though often used to simulate ship-generated waves, is rarely applied to unsteady motion. A Cartesian grid-based unsteady 2D+t method is developed in this paper, which enables the simulation of the unsteady motions of high-speed vessels at semi-planning or near-planning states. A method for incorporating unsteady motion within the framework of 2D+t theory is proposed in the paper, along with the introduction of a novel central processing unit based multi-threaded task parallel method for multi-section parallel computation. With this method, a 3D unsteady motion problem of high-speed vessels is transformed into several 2D unsteady motion problems of deformable bodies. The proposed model is validated with selected cases, showing that the model is capable of simulating unsteady motion problems of high-speed vessels.
Thermo-hydrodynamics of a condensing Taylor bubble in a vertical tube filled with subcooled liquid
Authors: Patel Saurabh , Kumar Rohit , Kumar Parmod
Published: December 2024

Taylor bubbles are often present in steam generation systems and heat transfer applications. The present study examines the interfacial behavior during condensation of a Taylor bubble in a quiescent subcooled water tube. The effect of Jacob number and Eötvös number on the shape and lifetime of the bubble, drag coefficient, and heat flux is studied by employing the volume of fluid method. During its spatiotemporal evolution, the bubble shape has transformed from a bullet nose to a wobbling bubble regime, and the lifetime of the Taylor bubble decreased with an increase in Jacob number and Eötvös number. The time-averaged heat flux from the bubble interface has increased with the Jacob and Eötvös numbers. Furthermore, the effect of converging and diverging tubes on the bubble dynamics is investigated. The use of diverging tubes is beneficial for faster condensation of Taylor bubbles.
Deformation and breakup of a droplet in media with density contrasts: A numerical study using the color-gradient lattice Boltzmann method
Authors: Jeong Jiyun , Lee Young Ki
Published: December 2024

We investigate the deformation and breakup behavior of a single droplet in shear and extensional flows, focusing on the effects of the density contrast between the droplet (dispersed phase) and the surrounding matrix fluid (continuous phase). Although many studies have explored the droplet dynamics in such flows, the influence of the density ratio is not yet fully understood. To address this gap, we employ the color-gradient lattice Boltzmann method and perform numerical analysis across a wide range of density ratios and capillary numbers in the Stokes flow regime. We quantify the droplet deformation, elucidate the effects of the density ratio, and carefully analyze the breakup modes, including tip streaming breakup. We confirm that the tip streaming breakup occurs only when the density contrast is large, with values ranging from approximately 1:100 to 1:300 within the test limits. Finally, the flow fields within the droplet are analyzed to elucidate the hydrodynamic origins of these distinct breakup modes.
Linear temporal instabilities and transient energy growth in rotating curved microchannel flow
Authors: Bera Suman , Shit Gopal Chandra , Reza Motahar , Drese Klaus Stefan
Published: December 2024

Owing to the inspiration from the advancements in microfluidic device applications, we analyze linear stability and maximum energy growth amplification in rotating curved microchannel flows. We numerically investigate linear perturbations to a fully developed stable base flow in a rotating curved microchannel by employing the spectral collocation method after transforming the Navier–Stokes system into coupled Orr–Sommerfeld and Squire equations. We estimate the temporal growth rate of the Tollmein–Schlichting wave and the neutral stability bounds driven by the Coriolis and centrifugal forces. At low rotational numbers and small curvature of the channel, we identify four distinct modal instabilities based on the positive growth rate, even at a low Reynolds number within the range for microfluidic devices. By investigating marginal instabilities and critical parameter values, we propose designs for efficient and portable curved microchannels aimed at controlling mixing efficiency. The novelty of the present study is the introduction of curvature of a curved microchannel in a rotating system and its impact on Dean vortices, predicting an early transition to instabilities. Our findings reveal the unstable regions of transient energy growth in a rotating curved microchannel, as highlighted by numerical range and eigenspectrum. Eigenspectrum analysis cannot precisely estimate instabilities, but numerical ranges of transient energy growth offer this capability. In comparison to earlier studies, we report a lower critical Reynolds number of 44 and a critical Dean number of 20 for moderate rotation rates and small curvature of the channel. Employing the transient energy growth analysis, we determine the efficient mixing time, revealing a decreasing function of the Dean number. The concept presented here can potentially assist in the manipulation of interactions of multiple vortices for further studies in mixing phenomena.
Impact of bottom explosions on wave formation in the presence of an inertial surface and wave current in a viscous fluid
Authors: Prasad Indra Mani , Behera Harekrushna , Hsu Tai-Wen , Zheng Siming , Mandal B. N.
Published: December 2024

This study examines the impact of a bottom explosion on wave generation in an inertial surface, considering the roles of fluid viscosity, wave current, and the nature of a slippery porous sea bottom. The Fourier and Laplace transform techniques are employed to calculate the surface elevation in terms of an infinite integral. Further, the infinite integral is evaluated asymptotically using the stationary-phase approach for larger time and distance values. The influence of viscosity, inertial surface, current, and slip parameters on wave generation is analyzed for different times and distances. The study reveals that the presence of an inertial surface lessens the amplitude of free surface elevation. Further, the free surface elevation's amplitude reduces as the current speed and liquid viscosity approach closer to a small value. In the case of a slippery porous bottom, as the slip parameter increases, the free surface elevation's amplitude decreases.
Grid-point requirements for direct numerical simulation of compressible turbulent boundary layers
Authors: Lyu Fuzhou , Xu Chunxiao
Published: December 2024

The grid-point requirements (N) for direct numerical simulation (DNS) of compressible turbulent boundary layers are estimated. By assuming the grids are nested and allowing grid spacing to scale with the Kolmogorov length scale, we find that N∼Reτ2.23(Tw/Tr)1.93 for Ma∞≤1, N∼Reτ2.23Ma∞1.35(Tw/Tr)1.93 for 1<Ma∞<5, and N∼Reτ2.23Ma∞3.15(Tw/Tr)1.93 for Ma∞≥5, where Reτ is the friction Reynolds number, Ma∞ is the free-stream Mach number, Tw and Tr are the wall temperature and recovery temperature, respectively. This paper demonstrates the necessity of reevaluating the grid-point requirements for DNS when compressibility effects are significant.
How does mitochondrial Ca2+ change during ischemia and reperfusion? Implications for activation of the permeability transition pore
Authors: Murphy Elizabeth , Eisner David A.
Published: December 2024

Cardiac ischemia followed by reperfusion results in cardiac cell death, which has been attributed to an increase of mitochondrial Ca2+ concentration, resulting in activation of the mitochondrial permeability transition pore (PTP). Evaluating this hypothesis requires understanding of the mechanisms responsible for control of mitochondrial Ca2+ in physiological conditions and how they are altered during both ischemia and reperfusion. Ca2+ influx is thought to occur through the mitochondrial Ca2+ uniporter (MCU). However, with deletion of the MCU, an increase in mitochondrial Ca2+ still occurs, suggesting an alternative Ca2+ influx mechanism during ischemia. There is less certainty about the mechanisms responsible for Ca2+ efflux, with contributions from both Ca2+/H+ exchange and a Na+-dependent Ca2+ efflux pathway. The molecular details of both mechanisms are not fully resolved. We discuss this and the contributions of both pathways to the accumulation of mitochondrial Ca2+ during ischemia and reperfusion. We further discuss the role of mitochondrial Ca2+ in activation of the PTP.
Revisiting the optoelectronic properties of sputtered aluminium-doped zinc oxide: a study combining advanced optical dispersion models
Authors: Enrique L A , Mishra S , Serquen E , Bravo F , Lizárraga K , Cespedes D , Piñeiro M , Llontop P , Guerra J A
Published: December 2024

Aluminium-doped zinc oxide (AZO) thin films with different aluminium (Al) concentrations were grown by RF-magnetron sputtering with substrate active cooling. Sputtering induced sample heating was aimed to be mitigated by the applied cooling, achieving films with electrical resistivities as low as

3.3
×

10

−
3

 

Ω
⋅

cm

, in the as-deposited state. Subsequently, an annealing treatment was performed to enhance the electrical properties and assess the effect of the Al concentration. The absorption coefficient spectra of zinc oxide (ZnO) exhibits an excitonic absorption contribution to the fundamental absorption that is typically not considered in AZO when determining the optical bandgap. Nevertheless, here we show that this free exciton band remains visible in AZO even at Al concentrations greater than 4 at.%. Additionally, the doping-induced defect states increases the width of tail states. These two factors have a substantial effect on the absorption edge, and thus must be considered with adequate models when attempting to determine the optical bandgap. In this work, we use a recently developed Elliot-based optical dispersion model to accurately determine the optical bandgap, exciton binding energy and Urbach energy of AZO thin films. On the other hand, we assess the infrared free carrier absorption, typically modeled by the Drude dispersion formula, by considering a complex frequency-dependent dynamical resistivity and the polar nature of the ZnO lattice. Normally, the real part of the dynamical resistivity follows a power law dependence and the exponent is assumed to be −1.5 for highly-doped semiconductors. Notwithstanding, here we let this exponent as a free fitting parameter to assess the effect of distinct scattering mechanisms present in sputtered AZO thin films and its dependence with the Al doping concentration. We believe these results can be extended to other degenerated semiconductors and are relevant for the understanding and tailoring of their fundamental optoelectronic properties.
Advancing machine fault diagnosis: a detailed examination of convolutional neural networks
Authors: Vashishtha Govind , Chauhan Sumika , Sehri Mert , Hebda-Sobkowicz Justyna , Zimroz Radoslaw , Dumond Patrick , Kumar Rajesh
Published: December 2024

The growing complexity of machinery and the increasing demand for operational efficiency and safety have driven the development of advanced fault diagnosis techniques. Among these, convolutional neural networks (CNNs) have emerged as a powerful tool, offering robust and accurate fault detection and classification capabilities. This comprehensive review delves into the application of CNNs in machine fault diagnosis, covering its theoretical foundation, architectural variations, and practical implementations. The strengths and limitations of CNNs are analyzed in this domain, discussing their effectiveness in handling various fault types, data complexities, and operational environments. Furthermore, we explore the evolving landscape of CNN-based fault diagnosis, examining recent advancements in data augmentation, transfer learning, and hybrid architectures. Finally, the future research directions and potential challenges to further enhance the application of CNNs for reliable and proactive machine fault diagnosis are highlighted.
Stability of Couette flow for 2D tropical climate system with zero thermal dissipation
Authors: Niu Dongjuan , Wu Huiru
Published: December 2024

In this paper, we investigate the nonlinear stability of Couette flow for the two-dimensional tropical climate system with zero thermal dissipation in the domain

T

×

R

. To overcome the difficulty caused by the absence of the thermal dissipation, we fully exploit the structure of the system and the enhanced dissipation created by the non-self-adjoint operator

y

∂

x

−
Δ

to obtain the expected stability result.
Boundary effects on the emergence of quasi-periodic solutions for Euler equations
Authors: Hassainia Zineb , Roulley Emeric
Published: December 2024

In this paper, we highlight the importance of the boundary effects on the construction of quasi-periodic vortex patches solutions close to Rankine vortices and whose existence is not known in the whole space due to the resonances of the linear frequencies. Availing of the lack of invariance by radial dilation of Euler equations in the unit disc and using a Nash–Moser implicit function iterative scheme we show the existence of such structures when the radius of the Rankine vortex belongs to a suitable massive Cantor-like set with almost full Lebesgue measure.
Feasibility of reconstructing in-vivo patient 3D dose distributions from 2D EPID image data using convolutional neural networks
Authors: Gao Ning , Cheng Bo , Wang Zhi , Li Didi , Chang Yankui , Ren Qiang , Pei Xi , Shi Chengyu , Xu Xie George
Published: December 2024

Objective. The primary purpose of this work is to demonstrate the feasibility of a deep convolutional neural network (dCNN) based algorithm that uses two-dimensional (2D) electronic portal imaging device (EPID) images and CT images as input to reconstruct 3D dose distributions inside the patient. Approach. To generalize dCNN training and testing data, geometric and materials models of a VitalBeam accelerator treatment head and a corresponding EPID imager were constructed in detail in the GPU-accelerated Monte Carlo dose computing software, ARCHER. The EPID imager pixel spatial resolution ranging from 1.0 mm to 8.5 mm was studied to select optimal pixel size for simulation. For purposes of training the U-Net-based dCNN, a total of 101 clinical intensive modulated radiation treatment cases—81 for training, 10 for validation, and 10 for testing—were simulated to produce comparative data of 3D dose distribution versus 2D EPID image data. The model’s accuracy was evaluated by comparing its predictions with Monte Carlo dose. Main Results. Using the optimal EPID pixel size of 1.5 mm, it took about 18 min to simulate the particle transport in patient-specific CT and EPID imager per a single field. In contrast, the trained dCNN can predict 3D dose distributions in about 0.35 s. The average 3D gamma passing rates between ARCHER and predicted doses are 99.02 ± 0.57% (3%/3 mm) and 96.85 ± 1.22% (2%/2 mm) for accumulated fields, respectively. Dose volume histogram data suggest that the proposed dCNN 3D dose prediction algorithm is accurate in evaluating treatment goals. Significance. This study has proposed a novel deep-learning model that is accurate and rapid in predicting 3D patient dose from 2D EPID images. The computational speed is expected to facilitate clinical practice for EPID-based in-vivo patient-specific quality assurance towards adaptive radiation therapy.
ATLAS New Small Wheel performance studies with LHC Run3 data
Authors: Arcangeletti C. ,   the ATLAS Muon Spectrometer group
Published: December 2024

The most important ATLAS upgrade for LHC run-3 has been in the Muon Spectrometer, where the replacement of the two forward inner stations with the New Small Wheels (NSW) introduced two novel detector technologies: the small strip Thin Gap Chambers (sTGC) and the resistive strips MicroMegas (MM). The integration of the two NSW in the ATLAS end-caps marks the culmination of an extensive construction, testing, and installation program. The NSW actively contributes to the muon spectrometer trigger and tracking, during the concurrent finalisation of the commissioning phase of this innovative system and the optimisation of its performances. This proceeding will offer an overview of the strategies employed for simulation and reconstruction integration and optimisation, followed by a detailed report on the performance studies of the NSW system during its initial operation with LHC Run3 data.
Hydrogen production with grid-connected electrolysis: scenario-based analysis of the EU criteria for renewable fuels
Authors: Thaler Bernhard , Pirker Gerhard , Wermuth Nicole
Published: December 2024

Renewable hydrogen (H2) will play a pivotal role in the decarbonization of the energy and industrial sectors. However, during the transition to a clean energy system, the production of H2 with electrolysis runs the risk of increasing carbon dioxide (CO2) emissions if the electricity system is still partly based on fossil fuels. The European Union has set ambitious targets for the production of H2 and defined strict rules in delegated acts to the renewable energy directive, when H2 produced with public grid electricity can be counted as renewable. This paper analyzes two grid criteria central to these rules, renewable energy share and CO2 emission intensity, in several future scenarios of the European energy system. By uniquely focusing on the impact of H2 production from the perspective of EU grid criteria, this study offers a novel assessment of how these regulations interact with the evolving energy landscape. Fulfillment of the renewable H2 grid criteria strongly depends on the future build-out of renewable energy resources, electricity demand, and amount of domestically produced H2. In a scenario with ambitious renewable build-out until 2030, represented by current drafts of national energy and climate plans, many countries will meet the stated criteria. However, adding a high amount of domestically produced H2 partly cancels out this effect. In a scenario with reduced renewable build-outs, comparable to historically achieved renewable resource additions, many fewer countries achieve the grid criteria. Finally, net CO2 emission reductions are analyzed by comparing power sector emission changes with the opportunity emissions that result from fossil fuels replacements with H2. The results indicate that using H2 in CO2 intensive use cases can lead to emission reductions, even if grid criteria are below the thresholds defined in the delegated acts. However, reduced renewable energy expansion poses the risk of not achieving any emission reductions at all with the produced H2.
Curvature of Gaussian quantum states
Authors: Miller Harry J D
Published: December 2024

The space of quantum states can be endowed with a metric structure using the second order derivatives of the relative entropy, giving rise to the so-called Kubo–Mori–Bogoliubov inner product. We explore its geometric properties on the submanifold of faithful, zero-displacement Gaussian states parameterised by their covariance matrices, deriving expressions for the geodesic equations, curvature tensors and scalar curvature. Our analysis suggests that the curvature of the manifold is strictly monotonic with respect to the von Neumann entropy, and thus can be interpreted as a measure of state uncertainty. This provides supporting evidence for the Petz conjecture in continuous variable systems.
Spin Hamiltonian with large fourth order terms: triple well potentials and Bloch sphere visualization
Authors: Lohr-Robles D S , Grether M , López-Moreno E , Hess P O
Published: December 2024

We present a study of a general spin Hamiltonian with terms up to fourth order. The semiclassical potential is obtained as the expectation value of the parameter dependent Hamiltonian in the coherent state basis, and using catastrophe theory its parameter space is constructed. Considering the components of the magnetic field as the free parameters, we found regions where the semiclassical potential has three stability wells when the parameters of the fourth order terms are large. Using the coherent states we are able to visualize the localization of the ground state eigenfunction on the Bloch sphere as the magnetic field is varied.
Enhancing tribological and corrosion characteristics of AA2099/GNP metal matrix nanocomposites through parametric optimization using Taguchi Technique
Authors: Polayya Ch , Rao C S P , G B Veeresh Kumar
Published: December 2024

The synergy between AA2099 alloys and Graphene Nanoparticles (GNP) harnesses the potential of ultrasonic-assisted stir casting to create metal matrix composites (MMCs). The GNP content is systematically varied (0%, 0.1%, 0.2%, and 0.3%) within the AA2099 alloy matrix. The microstructural analysis employs scanning electron microscopy (SEM) and x-ray diffraction (XRD), while hardness is evaluated using specialized Vickers microhardness equipment. The results reveal a significant improvement in hardness with increasing GNP reinforcement content. Wear behavior investigations utilize pin-on-disc wear tests, guided by the Taguchi Technique and analyzed through an L16 array. Additionally, the influence of various factors on the wear rate and coefficient of friction (COF) is systematically analyzed using Analysis of Variance (ANOVA), highlighting the significant role of GNP content in both wear behavior and COF in these MMCs. SEM analysis of wear fractography provides insights into the fracture behavior of the specimens, elucidating wear mechanisms at the microscale. Lastly, corrosion testing demonstrated that higher GNP content enhances corrosion resistance, as indicated by lower corrosion current density and less negative corrosion potential. Optical microscopy (OM) confirmed that increased GNP content reduces corrosion pit size and enhances protective layer formation.
Synergistic effects of Na2O on structural, physical, optical, and bioactive properties of SrO-SiO2-ZrO2 glasses for biomedical applications
Authors: Sachan Akash , Mishra Rajat Kumar , Avinashi Sarvesh Kumar , Shweta  , Behera Priyatama , Kumar Saurabh , Parveen Shama , Banerjee Monisha , Mishra Monalisa , Rakhi  , Kumari Savita , Gautam Chandkiram
Published: December 2024

Sodium oxide (Na2O) doped glasses are promising materials for numerous biomedical applications due to their improved structural and biocompatibility. Herein, the glasses within a system (45-x)SrO-45SiO2-10ZrO2-xNa2O (where, 0 ≤ x ≤ 6) were fabricated via a melt-quenching technique. The glassy phase (amorphous nature) of the prepared glasses was confirmed through x-ray diffraction (XRD) analysis. Further, various structural, physical, optical, and biological studies were assessed. The obtained density of the synthesized glasses was observed to be in the range of 3.51–3.76 g cm−3. Further, in order to study the structural behaviors of the glass samples, FTIR spectroscopy was performed. However, various optical parameters like band gap, Urbach energy, skin depth, optical basicity, refractive indices etc were determined with the help of UV-visible spectroscopic technique. Further, particle size was calculated via ‘dynamic light scattering’ (DLS) technique and found to be decreased from 825 nm to 51 nm. To check the biocompatibility of the glass samples, the MTT assay performed on the treated cancer cells. Furthermore, toxicology of the samples was assessed using DAPI, DCFH-DA staining, and trypan blue assay. These findings revealed that synthesized glasses are a feasible material for innumerable biomedical applications, particularly for bone and tooth implants.