bluuebunny/crossref_metadata_2025 huggingface dataset:
VA Outreach Is an Essential Area for Improving Veterans’ Health Care Accessibility
Authors: Stryczek Krysttel C , Honsberger Mark , Ball Sherry L , Barnard Juliana G , Young Jessica P , Felker Bradford , Au David H , Ho P Michael , Kirsh Susan R , Sayre George G
Published: February 2023

Introduction

The Veterans Health Administration (VHA) is tasked with providing access to health care to veterans of military service. However, many eligible veterans have either not yet enrolled or underutilized VHA services. Further study of barriers to access before veterans enroll in VHA care is necessary to understand how to address this issue. The ChooseVA (née MyVA Access) initiative aims to achieve this mission to improve veterans’ health care access. Although veteran outreach was not specifically addressed by the initiative, it is a critical component of improving veterans’ access to health care. Findings from this multisite evaluation of ChooseVA implementation describe sites’ efforts to improve VHA outreach and veterans’ experiences with access.

Materials and Methods

This quality improvement evaluation employed a multi-method qualitative methodology, including 127 semi-structured interviews and 81 focus groups with VHA providers and staff (“VHA staff”) completed during 21 VHA medical center facility site visits between July and November 2017 and 48 telephone interviews with veterans completed between May and October 2018. Interviews and focus groups were transcribed and analyzed using deductive and inductive analysis to capture challenges and strategies to improve VHA health care access (VHA staff data), experiences with access to care (veteran data), barriers and facilitators to care (staff and veteran data), contextual factors, and emerging categories and themes. We developed focused themes describing perceived challenges, descriptions of VHA staff efforts to improve veteran outreach, and veterans’ experiences with accessing VHA health care.

Results

VHA staff and veteran respondents reported a lack of veteran awareness of eligibility for VHA services. Veterans reported limited understanding of the range of services offered. This awareness gap served as a barrier to veterans’ ability to successfully access VHA health care services. Veterans described this awareness gap as contributing to delayed VHA enrollment and delayed or underutilized health care benefits and services. Staff focused on community outreach and engaging veterans for VHA enrollment as part of their efforts to implement the ChooseVA access initiative. Staff and veteran respondents agreed that outreach efforts were helpful for engaging veterans and facilitating access.

Conclusions

Although efforts across VHA programs informed veterans about VHA services, our results suggest that both VHA staff and veterans agreed that missed opportunities exist. Gaps include veterans’ lack of awareness or understanding of VHA benefits for which they qualify for. This can result in delayed access to care which may negatively impact veterans, including those separating from the military and vulnerable populations such as veterans who experience pregnancy or homelessness.
A survey for variable young stars with small telescopes – VII. Spot properties on YSOs in IC 5070
Authors: Herbert Carys , Froebrich Dirk , Scholz Aleks
Published: February 2023

We present measurements of spot properties on 31 young stellar objects, based on multiband data from the HOYS (Hunting Outbursting Young Stars) project. On average the analysis for each object is based on 270 data points during 80 d in at least three bands. All the young low-mass stars in our sample show periodic photometric variations. We determine spot temperatures and coverage by comparing the measured photometric amplitudes in optical bands with simulated amplitudes based on atmosphere models, including a complete error propagation. 21 objects in our sample feature cool spots, with spot temperatures 500–2500 K below the stellar effective temperature (Teff), and a coverage of 0.05–0.4. Six more have hot spots, with temperatures up to 3000 K above Teff and coverage below 0.15. The remaining four stars have ambiguous solutions or are AA Tau-type contaminants. All of the stars with large spots (i.e. high coverage >0.1) are relatively cool with Teff < 4500 K, which could be a result of having deeper convection zones. Apart from that, spot properties show no significant trends with rotation period, infrared excess, or stellar properties. Most notably, we find hot spots in stars that do not show K − W2 infrared excess, indicating the possibility of accretion across an inner disc cavity or the presence of plage.
The cosmic ray ionization and γ-ray budgets of star-forming galaxies
Authors: Krumholz Mark R , Crocker Roland M , Offner Stella S R
Published: February 2023

Cosmic rays in star-forming galaxies are a dominant source of both diffuse γ-ray emission and ionization in gas too deeply shielded for photons to penetrate. Though the cosmic rays responsible for γ-rays and ionization are of different energies, they are produced by the same star formation-driven sources, and thus galaxies’ star formation rates, γ-ray luminosities, and ionization rates should all be linked. In this paper, we use up-to-date cross-section data to determine this relationship, finding that cosmic rays in a galaxy of star formation rate $\dot{M}_*$ and gas depletion time tdep produce a maximum primary ionization rate ζ ≈ 1 × 10−16(tdep/Gyr)−1 s−1 and a maximum γ-ray luminosity $L_\gamma \approx 4\times 10^{39} (\dot{M}_*/\mathrm{M}_\odot \mbox{ yr}^{-1})$ erg s−1 in the 0.1–100 GeV band. These budgets imply either that the ionization rates measured in Milky Way molecular clouds include a significant contribution from local sources that elevate them above the Galactic mean, or that CR-driven ionization in the Milky Way is enhanced by sources not linked directly to star formation. Our results also imply that ionization rates in starburst systems are only moderately enhanced compared to those in the Milky Way. Finally, we point out that measurements of γ-ray luminosities can be used to place constraints on galactic ionization budgets in starburst galaxies that are nearly free of systematic uncertainties on the details of cosmic ray acceleration.
Study of maximum electron energy of sub-PeV pulsar wind nebulae by multiwavelength modelling
Authors: Joshi Jagdish C , Tanaka Shuta J , Miranda Luis Salvador , Razzaque Soebur
Published: February 2023

Recently, the Large High Altitude Air Shower Observatory (LHAASO) reported the discovery of 12 ultrahigh-energy (UHE; ε ≥ 100 TeV) gamma-ray sources located in the Galactic plane. A few of these UHE gamma-ray emitting regions are in spatial coincidence with pulsar wind nebulae (PWNe). We consider a sample of five sources: two of them are LHAASO sources (LHAASO J1908+0621 and LHAASO J2226+6057) and the remaining three are GeV–TeV gamma-ray emitters. In addition, X-rays, radio observations, or upper limits are also available for these objects. We study multiwavelength radiation from these sources by considering a PWN origin, where the emission is powered by spin-down luminosity of the associated pulsars. In this Leptonic emission model, the electron population is calculated at different times under the radiative (synchrotron and inverse-Compton) and adiabatic cooling. We also include the onset of the reverberation phase for the PWN, by assuming radially symmetric expansion. However, in this work, we find that multiwavelength emission can be interpreted before the onset of this phase. The maximum energy of the electrons based on the spectral fit is found to be above 0.1 PeV and close to 1 PeV. For LHAASO J2226+6057, using its observations in radio to UHE gamma-rays, we find that UHE gamma-rays can be interpreted using electrons with maximum energy of 1 PeV. We estimate the upper limits on the minimum Lorentz factor of the electrons and it also infers the minimum value of the pair-multiplicity of charged pairs.
Cosmic-ray-driven galactic winds: transport modes of cosmic rays and Alfvén-wave dark regions
Authors: Thomas T , Pfrommer C , Pakmor R
Published: February 2023

Feedback mediated by cosmic rays (CRs) is an important process in galaxy formation. Because CRs are long-lived and because they are transported along the magnetic field lines independently of any gas flow, they can efficiently distribute their feedback energy within the galaxy. We present an in-depth investigation of (i) how CRs launch galactic winds from a disc that is forming in a $10^{11} \, \rm {M}_\odot$ halo and (ii) the state of CR transport inside the galactic wind. To this end, we use the arepo moving-mesh code and model CR transport with the two-moment description of CR hydrodynamics. This model includes the CR interaction with the gyroresonant Alfvén waves that enable us to self-consistently calculate the CR diffusion coefficient and CR transport speeds based on coarse-grained models for plasma physical effects. This delivers insight into key questions such as whether the effective CR transport is streaming-like or diffusive-like, how the CR diffusion coefficient and transport speed change inside the circumgalactic medium, and to what degree the two-moment approximation is needed to faithfully capture these effects. We find that the CR-diffusion coefficient reaches a steady state in most environments with the notable exception of our newly discovered Alfvén-wave dark regions where the toroidal wind magnetic field is nearly perpendicular to the CR pressure gradient so that CRs are unable to excite the gyroresonant Alfvén waves. However, CR transport itself cannot reach a steady state and is not well described by either the CR streaming paradigm, the CR diffusion paradigm, or a combination of both.
Linking the interiors and surfaces of magnetic stars
Authors: Fuller Jim , Mathis Stéphane
Published: February 2023

Strong magnetic fields are observed in a substantial fraction of upper main sequence stars and white dwarfs. Many such stars are observed to exhibit photometric modulations as the magnetic poles rotate in and out of view, which could be a consequence of magnetic perturbations to the star’s thermal structure. The magnetic pressure is typically larger than the gas pressure at the star’s photosphere, but much smaller than the gas pressure in the star’s interior, so the expected surface flux perturbations are not clear. We compute magnetically perturbed stellar structures of young $3 \, \mathrm{M}_\odot$ stars that are in both hydrostatic and thermal equilibrium, and which contain both poloidal and toroidal components of a dipolar magnetic field as expected for stable fossil fields. This provides semi-analytical models of such fields in baroclinic stably stratified regions. The star’s internal pressure, temperature, and flux perturbations can have a range of magnitudes, though we argue the most likely configurations exhibit flux perturbations much smaller than the ratio of surface magnetic pressure to surface gas pressure, but much larger than the ratio of surface magnetic pressure to central gas pressure. The magnetic pole is hotter than the equator in our models, but a cooler magnetic pole is possible depending on the magnetic field configuration. The expected flux variations for observed field strengths are δL/L ≲ 10−6, much smaller than those observed in magnetic stars, suggesting that observed perturbations stem from changes to the emergent spectrum rather than changes to the bolometric flux.
Spectral shapes of the Ly α emission from galaxies – II. The influence of stellar properties and nebular conditions on the emergent Ly α profiles
Authors: Hayes Matthew J , Runnholm Axel , Scarlata Claudia , Gronke Max , Rivera-Thorsen T Emil
Published: February 2023

We demonstrate how the stellar and nebular conditions in star-forming galaxies modulate the emission and spectral profile of H i Ly α emission line. We examine the net Ly α output, kinematics, and in particular emission of blueshifted Ly α radiation, using spectroscopy from with the Cosmic Origins Spectrograph on Hubble Space Telescope (HST), giving a sample of 87 galaxies at redshift z = 0.05−0.44. We contrast the Ly α spectral measurements with properties of the ionized gas (from optical spectra) and stars (from stellar modelling). We demonstrate correlations of unprecedented strength between the Ly α escape fraction (and equivalent width) and the ionization parameter (p ≈ 10−15). The relative contribution of blueshifted emission to the total Ly α also increases from ≈0 to ≈40 per cent over the range of O32 ratios (p ≈ 10−6). We also find particularly strong correlations with estimators of stellar age and nebular abundance, and weaker correlations regarding thermodynamic variables. Low ionization stage absorption lines suggest the Ly α emission and line profile are predominantly governed by the column of absorbing gas near zero velocity. Simultaneous multiparametric analysis over many variables shows we can predict 80 per cent of the variance on Ly α luminosity, and ∼50 per cent on the EW. We determine the most crucial predictive variables, finding that for tracers of the ionization state and H β luminosity dominate the luminosity prediction whereas the Ly α EW is best predicted by H β EW and the H α/H β ratio. We discuss our results with reference to high-redshift observations, focussing upon the use of Ly α to probe the nebular conditions in high-z galaxies and cosmic reionization.
Prediction for the amplitude and second maximum of Solar Cycle 25 and a comparison of the predictions based on strength of polar magnetic field and low-latitude sunspot area
Authors: Javaraiah J
Published: February 2023

The maximum of a solar cycle contains two or more peaks, known as Gnevyshev peaks. Studies of this property of solar cycles may help in better understanding the solar dynamo mechanism. We analysed the 13-month smoothed monthly mean Version-2 international sunspot number (SN) during the period 1874–2017 and found that there exists a good correlation between the amplitude (value of the main and highest peak) and the value of the second maximum (value of the second highest peak) during the maximum of a solar cycle. Using this relationship and the earlier predicted value 86 ± 18 (92 ± 11) of the amplitude of Solar Cycle 25, here we predict a value 73 ± 15 (79 ± 15) for the second maximum of Solar Cycle 25. The ratio of the predicted second maximum to the amplitude is found to be 0.85, almost the same as that of Solar Cycle 24. The least-square cosine fits to the values of the peaks that occurred first and second during the maxima of Solar Cycles 12–24 suggest that in Solar Cycle 25 the second maximum would occur before the main maximum, the same as in Solar Cycle 24. However, these fits suggest ≈106 and ≈119 for the second maximum and the amplitude of Solar Cycle 25, respectively. Earlier, we analysed the combined Greenwich and Debrecen sunspot-group data during 1874–2017 and predicted the amplitude of Solar Cycle 25 from the activity just after the maximum of Solar Cycle 24 in the equatorial latitudes of the Sun’s Southern hemisphere. Here, from the hindsight of the results we found the earlier prediction is reasonably reliable. We analysed the polar-fields data measured in Wilcox Observatory during Solar Cycles 20–24 and obtained a value 125 ± 7 for the amplitude of Solar Cycle 25. This is slightly larger – whereas the value ≈86 (≈92) predicted from the activity in the equatorial latitudes is slightly smaller – than the observed amplitude of Solar Cycle 24. This difference is discussed briefly.
How the existence of unstable neutral media restricts the aspect ratio of cold neutral media?
Authors: Ho Ka Wai , Yuen Ka Ho , Lazarian Alex
Published: February 2023

The ubiquity of very thin and lengthy cold neutral medium (CNM) has been reported by multiple authors in the H i community. Yet, the reason of how the CNM can be so long and lengthy is still in debate. In this paper, we recognize a new type of instability due to the attractive nature of the pressure force in the unstable phase. We provide a new estimation of the average CNM filament aspect ratio with the consideration of force balances at the phase boundary, which is roughly 5–20 in common CNM environment. We show that most of the cold filaments are less filamentary than what usually predicted via MHD turbulence theory or inferred from observations: The average length of CNM filament is roughly 1/2 of that in isothermal MHD turbulence with similar turbulence conditions. This suggests that the ‘cold filaments’ that are identified in observations might not be in pressure equilibrium or generated via other mechanisms.
High-energy neutrino emission from magnetized jets of rapidly rotating protomagnetars
Authors: Bhattacharya Mukul , Carpio Jose A , Murase Kohta , Horiuchi Shunsaku
Published: February 2023

Relativistic jets originating from protomagnetar central engines can lead to long duration gamma-ray bursts (GRBs) and are considered potential sources of ultra-high-energy cosmic rays and secondary neutrinos. We explore the propagation of such jets through a broad range of progenitors, from stars which have shed their envelopes to supergiants which have not. We use a semi-analytical spin-down model for the strongly magnetized and rapidly rotating protoneutron star (PNS) to investigate the role of central engine properties such as the surface dipole field strength, initial rotation period, and jet opening angle on the interactions and dynamical evolution of the jet-cocoon system. With this model, we determine the properties of the relativistic jet, the mildly relativistic cocoon, and the collimation shock in terms of system parameters such as the time-dependent jet luminosity, injection angle, and density profile of the stellar medium. We also analyse the criteria for a successful jet breakout, the maximum energy that can be deposited into the cocoon by the relativistic jet, and structural stability of the magnetized outflow relative to local instabilities. Lastly, we compute the high-energy neutrino emission as these magnetized outflows burrow through their progenitors. Precursor neutrinos from successful GRB jets are unlikely to be detected by IceCube, which is consistent with the results of previous works. On the other hand, we find that high-energy neutrinos may be produced for extended progenitors like blue and red supergiants, and we estimate the detectability of neutrinos with next generation detectors such as IceCube-Gen2.
VINTERGATAN-GM: The cosmological imprints of early mergers on Milky-Way-mass galaxies
Authors: Rey Martin P , Agertz Oscar , Starkenburg Tjitske K , Renaud Florent , Joshi Gandhali D , Pontzen Andrew , Martin Nicolas F , Feuillet Diane K , Read Justin I
Published: February 2023

We present a new suite of cosmological zoom-in hydrodynamical ($\approx 20\, \mathrm{pc}$ spatial resolution) simulations of Milky-Way mass galaxies to study how a varying mass ratio for a Gaia-Sausage-Enceladus (GSE) progenitor impacts the z = 0 chemodynamics of halo stars. Using the genetic modification approach, we create five cosmological histories for a Milky-Way-mass dark matter halo ($M_{200}\approx 10^{12} \, \mbox{M}_\mathrm{\odot }$), incrementally increasing the stellar mass ratio of a z ≈ 2 merger from 1:25 to 1:2, while fixing the galaxy’s final dynamical, stellar mass, and large-scale environment. We find markedly different morphologies at z = 0 following this change in early history, with a growing merger resulting in increasingly compact and bulge-dominated galaxies. Despite this structural diversity, all galaxies show a radially biased population of inner halo stars like the Milky-Way’s GSE which, surprisingly, has a similar magnitude, age, $\rm [Fe/H]$, and $\rm [\alpha /Fe]$ distribution whether the z ≈ 2 merger is more minor or major. This arises because a smaller ex-situ population at z ≈ 2 is compensated by a larger population formed in an earlier merger-driven starburst whose contribution to the GES can grow dynamically over time, and with both populations strongly overlapping in the $\rm [Fe/H]-\rm [\alpha /Fe]$ plane. Our study demonstrates that multiple high-redshift histories can lead to similar z = 0 chemodynamical features in the halo, highlighting the need for additional constraints to distinguish them, and the importance of considering the full spectrum of progenitors when interpreting z = 0 data to reconstruct our Galaxy’s past.
Horizontal Gene Transfer, Fitness Costs and Mobility Shape the Spread of Antibiotic Resistance Genes into Experimental Populations ofAcinetobacter Baylyi
Authors: Sezmis Aysha L , Woods Laura C , Peleg Anton Y , McDonald Michael J
Published: February 2023

Horizontal gene transfer (HGT) is important for microbial evolution, but how evolutionary forces shape the frequencies of horizontally transferred genetic variants in the absence of strong selection remains an open question. In this study, we evolve laboratory populations of Acinetobacter baylyi (ADP1) with HGT from two clinically relevant strains of multidrug-resistant Acinetobacter baumannii (AB5075 and A9844). We find that DNA can cross the species barrier, even without strong selection, and despite substantial DNA sequence divergence between the two species. Our results confirm previous findings that HGT can drive the spread of antibiotic resistance genes (ARGs) without selection for that antibiotic, but not for all of the resistance genes present in the donor genome. We quantify the costs and benefits of horizontally transferred variants and use whole population sequencing to track the spread of ARGs from HGT donors into antibiotic-sensitive recipients. We find that even though most ARGs are taken up by populations of A. baylyi, the long-term fate of an individual gene depends both on its fitness cost and on the type of genetic element that carries the gene. Interestingly, we also found that an integron, but not its host plasmid, is able to spread in A. baylyi populations despite its strong deleterious effect. Altogether, our results show how HGT provides an evolutionary advantage to evolving populations by facilitating the spread of non-selected genetic variation including costly ARGs.
You exhaust me! Air pollution exposure near schools during pick-up and drop-off times
Authors: Pitt Tona M , Rowe Brian H , Hicks Anne
Published: February 2023

Background

Public and healthcare practitioner awareness of climate change and the longitudinal health impacts of air pollution is growing; however, it is not always clear how to implement practical and feasible steps that individuals and communities can take to help decrease air pollution and protect children, and it can be challenging to request and enforce behaviour changes that the public associates with perceived personal inconvenience. In this context, it is important to consider common, chronic exposures that increase children’s risks, especially when straightforward solutions with minimal negative impact where significant evidence-based positive results are available.

Aims

This article provides simple tips that healthcare providers, parents, and communities can use to advocate for decreased idling in school zones to improve air quality in and around schools.
L’adhérence au traitement de maladies chroniques chez les jeunes – Rôle du niveau d’actualisation et de la tolérance au risque
Authors: Hurtubise Sandrine , Perez Tamara , Drouin Olivier
Published: February 2023

Adolescents with chronic diseases must adhere to medication regimens to control their symptoms and avoid long-term complications. Despite its importance, medication adherence is low among adolescents. This commentary briefly covers the challenges described in the literature associated with measuring and addressing low medication adherence in adolescents. Next, it presents the evidence for the link between medication adherence and two prevalent psychological characteristics that have not been properly assessed so far: delay discounting (i.e., the relative value assigned to the future compared to the present), and risk tolerance. These psychological traits deserve further studies and are potentially amenable to interventions to improve medication adherence in adolescents with chronic conditions.
A More Credible Approach to Parallel Trends
Authors: Rambachan Ashesh , Roth Jonathan
Published: February 2023

This paper proposes tools for robust inference in difference-in-differences and event-study designs where the parallel trends assumption may be violated. Instead of requiring that parallel trends holds exactly, we impose restrictions on how different the post-treatment violations of parallel trends can be from the pre-treatment differences in trends (“pre-trends”). The causal parameter of interest is partially identified under these restrictions. We introduce two approaches that guarantee uniformly valid inference under the imposed restrictions, and we derive novel results showing that they have desirable power properties in our context. We illustrate how economic knowledge can inform the restrictions on the possible violations of parallel trends in two economic applications. We also highlight how our approach can be used to conduct sensitivity analyses showing what causal conclusions can be drawn under various restrictions on the possible violations of the parallel trends assumption.
Regulatory T cells: a new therapeutic link for Sjögren syndrome?
Authors: Ming Bingxia , Zhu Yaowu , Zhong Jixin , Dong Lingli
Published: February 2023

Great advancements have been made in understanding the pathogenesis of SS, but there remain unmet needs for effective and targeted treatments. Glandular and extraglandular dysfunction in SS is associated with autoimmune lymphocytic infiltration that invades the epithelial structures of affected organs. Regulatory T (Treg) cells are a subset of CD4+ T lymphocytes that maintain self-tolerance during physiological conditions. Besides inhibiting excessive inflammation and autoimmune response by targeting various immune cell subsets and tissues, Treg cells have also been shown to promote tissue repair and regeneration in pathogenic milieus. The changes of quantity and function of Treg cells in various autoimmune and chronic inflammatory disorders have been reported, owing to their effects on immune regulation. Here we summarize the recent findings from murine models and clinical data about the dysfunction of Treg cells in SS pathogenesis and discuss the therapeutic strategies of direct or indirect targeting of Treg cells in SS. Understanding the current knowledge of Treg cells in the development of SS will be important to elucidate disease pathogenesis and may guide research for successful therapeutic intervention in this disease.
Epigenetic programming of TBX2/CX43 mediates lower sperm quality in male offspring induced by prenatal dexamethasone exposure
Authors: Liu Yi , Liu Yi , Chen Guanghui , Wang Hui
Published: February 2023

Decreased sperm quality is the main cause of male infertility. Studies have found that prenatal dexamethasone exposure (PDE) decreases sperm quality in male offspring after birth, but the mechanism is unclear. Wistar pregnant rats were subcutaneously injected with 0.1, 0.2, and 0.4 mg/kg.d dexamethasone at gestational days 9–20. The testes and sperm of first-generation (F1) offspring were collected, and F1 offspring were mated with wild-type female rats to obtain F2. Compared with the control group, F1 offspring in PDE group had lower sperm count and motility after birth, and the deformity rate increased. F2 fetal rats’ body length and weight decreased, and the intrauterine growth retardation rate increased. Meanwhile, PDE decreased the expression of connexin 43 (CX43) in offspring testes, whereas T-box transcription factor 2 (TBX2) promoter region histone 3 lysine 9 acetylation (H3K9ac) level and its expression were increased. Traced back to F1 fetus testes, PDE increased the expression of glucocorticoid receptor (GR) and P300, activated GR protein into the nucleus, and made GR act on the TBX2 promoter region. Further, a series of Sertoli cell interventions confirmed that dexamethasone promoted GR to recruit P300, increased the H3K9ac level of TBX2 promoter region and its expression, and inhibited the expression of CX43. This study confirmed that PDE decreased sperm quality of male offspring, which is related to the epigenetic programming of TBX2/CX43 in the Sertoli cells, provided a theoretical and experimental basis for guiding the rational use of drugs during pregnancy.
Piecewise model-based adaptive compensation control for high-speed trains with unknown actuator failures
Authors: Tan Chang , Zhang Junhui , Yang Hui , Zhang Leilei
Published: February 2023

In order to deal with the uncertainties caused by different operation conditions and unknown actuator failures of high-speed trains, an adaptive failures compensation control scheme is designed based on the piecewise model. A piecewise constant model is introduced to describe the variable system parameters caused by the variable operation environments, and a multiple-particle piecewise model of high-speed trains, with unknown actuator failures, is then established. An adaptive failure compensation controller is developed for the multiple-particle piecewise constant model, by using a direct model refering to the adaptive control method. Such an adaptive controller can not only compensate the uncertainties from unknown actuator failures, but also effectively deal with the uncertainties caused by different operating conditions. Finally, a CRH380A high-speed train model is taken as the controlled object for the simulation study. The simulation results show that the proposed controller ensures the desired system performance in the presence of unknown actuator failures and uncertain operation conditions.
Multi-component system maintenance optimization of a rail transit train based on opportunistic correlations
Authors: Dai Jisheng , Ding Rongjun , Fu Yong , Qin Yong
Published: February 2023

In order to deal with the problems of insufficient or excessive maintenance in the current maintenance activities of China transit trains, this paper develops a novel multi-component system maintenance optimization approach based on an opportunistic correlation model. Based on the minimal reliability and failure rate change rule of each train component, the novel proposed maintenance optimization benefits from an improved opportunistic maintenance model with system structure correlation, fault correlation and reliability correlation under imperfect maintenance. Then, different maintenance modes can be determined by a proposed maintenance factor under the different conditions of components. Specifically, the reliability threshold of each component is also considered to optimize the maintenance cost by the system reliability and operational availability of the train. Furthermore, as the mentioned problem belongs to the NP-Hard optimization problems, a modified particle swarm optimization (PSO) with the improvement of inertia weight is proposed to cope with the optimization problem. Based on a specific case under the practical recorded failure data, the analysis shows that the proposed model and approach can effectively cut the maintenance cost.
Simulation of fire emergency evacuation in a large-passenger-flow subway station based on the on-site measured data of Shenzhen Metro
Authors: Chen Hua , Zhang Chenyang , Zhang Jieyu , Shu Ya , Qi Xinjian , Jiang Chaozhe
Published: February 2023

Because of its large capacity, high efficiency and energy savings, the subway has gradually become the primary mode of transportation for citizens. A high density of passengers exists within a large-passenger-flow subway station, and the number of casualties and injuries during a fire emergency is substantial. In this paper, Pathfinder software and on-site measured data of Pingzhou station in Shenzhen (China) were utilized to simulate a fire emergency evacuation in a large-passenger-flow subway station. The Required Safe Egress Time (RSET), number of passengers and flow rates of stairs and escalators were analysed for three fire evacuation scenarios: train fire, platform fire and hall fire. The evacuation time of the train fire, which was 1173 s, was the longest, and 3621 occupants needed to evacuate when the train was fully loaded. Occupants could not complete the evacuation within 6 mins in all three fire evacuation scenarios, which does not meet the current standard requirements and codes. By changing the number of passengers and the number of stairs for evacuation, the flow rate capacity and evacuation time were explored, which have reference values for safety management and emergency evacuation plan optimization during peak hours of subway operation.
A High Immediate Postoperative Neutrophil-to-Albumin Ratio is Associated With Unfavorable Clinical Outcomes at Hospital Discharge in Patients With Aneurysmal Subarachnoid Hemorrhage
Authors: Shin Kyung Won , Choi Seungeun , Oh Hyongmin , Hwang So Yeong , Park Hee-Pyoung
Published: February 2023

Background:

Inflammation is associated with unfavorable clinical outcomes after aneurysmal subarachnoid hemorrhage (aSAH). We evaluated the relationship between postoperative neutrophil-to-albumin ratio (NAR) and unfavorable clinical outcomes (modified Rankin score ≥ 3) at hospital discharge in aSAH patients.

Methods:

Five hundred sixty aSAH patients undergoing surgical or endovascular treatment were included in this retrospective study. Patients were initially allocated to high (n=247) or low (n=313) postoperative NAR groups based on the immediate postoperative NAR cutoff value identified by receiver operating characteristic analysis, and then further subclassified into 4 groups: HH (high pre- and high postoperative NAR, n=156), LH (low preoperative and high postoperative NAR, n=91), HL (high preoperative and low postoperative NAR, n=68), and low pre- and low postoperative NAR (n=245).

Results:

Optimum cutoff values of immediate postoperative and preoperative NAR were 2.45 and 2.09, respectively. Unfavorable clinical outcomes were more frequent in patients with high compared with low postoperative NAR (45.3% vs. 13.4%; P < 0.001). In multivariate analysis, postoperative NAR was a significant predictor of unfavorable clinical outcomes (odds ratio, 2.10; 95% CI, 1.42-3.10; P < 0.001). Unfavorable clinical outcomes were less frequent in group low pre- and low postoperative NAR than in groups HH, LH, and HL (9.4% vs. 44.9%, 46.2% and 27.9%, respectively; all P < 0.001) and also in Group HL compared with groups HH and LH (P=0.026 and P=0.030); clinical outcomes did not differ between Groups HH and LH.

Conclusions:

A high immediate postoperative NAR was associated with unfavorable clinical outcomes at hospital discharge in aSAH patients.
Menstrual Technology Innovations and the Implications for Heavy Menstrual Bleeding
Authors: Liberty Abigail , Samuelson Bannow Bethany , Matteson Kristen , Edelman Alison , Colwill Alyssa
Published: February 2023

Menstruation is a personal and cultural experience with financial and health implications. Menstruation historically has been managed with disposable commodities, including tampons and pads. New technologies, including underwear and menstrual cups and discs, have emerged to address diverse menstrual needs such as prioritization of sustainability, discretion, and inclusivity. New technologies are not routinely integrated into history taking or validated questionnaires, which currently rely on traditional tampon and pad use for identifying individuals with heavy menstrual bleeding. Review of menstrual technologies and accessories provides insight to empower gynecologists and other clinicians to take comprehensive menstrual histories, including strategies for identification of heavy menstrual bleeding and troubleshooting menstrual disturbances, within the context of new menstrual technologies.
Skeletal Maturity in Legg-Calve-Perthes Disease: Significant Discrepancy Present Between the Hand and the Hip
Authors: Shaw K. Aaron , Herring John A.
Published: February 2023

Background:

The concept of delayed skeletal maturity in Legg-Calve-Perthes Disease (LCPD) has been well identified with the Greulich and Pyle (GP) atlas showing 1 to 2 years delay. Recently the optimized Oxford hip skeletal age (Optimized Oxford) system has been developed and shown to have similar accuracy as the GP atlas for assessing skeletal maturity. However, this system has not been used to assess skeletal maturity in LCPD.

Methods:

A retrospective review of a prospective, multicenter study of patients with LCPD treated from 1984 to 1991 and followed to skeletal maturity was performed. We identified all patients who had a left-hand radiograph at the time of presentation with an accompanying anteroposterior pelvis radiograph including the contralateral hip. Patients were excluded if their age at presentation fell outside the validated range for the Optimized Oxford system. GP atlas was used to determine bone age using left-hand radiographs and the nonaffected hip radiographs were used to calculate the Optimized Oxford bone age. Skeletal maturity indices were compared with chronological age (CA) to determine the discrepancy between methodologies.

Results:

A total of 71 patients met inclusion criteria (mean 9.5 ± 1.2 y at presentation, 42.2% females). The mean GP bone age was 1.4 years younger than CA (95% CI: 1.01-1.76 y), with the discrepancy being greater for boys than girls (1.8 vs 0.86 y, P = 0.02). The mean Optimized Oxford bone age was 0.31 years older than CA (95% CI: 0.24-0.38 y) and correlated significantly with CA (R = 0.97, P < 0.001). There were no sex differences in the Optimized Oxford bone age relative to CA (P = 0.32). The GP bone age was a mean of 1.7 years younger than the Optimized Oxford bone age (95% CI: 1.35-2.05 y).

Conclusion:

Skeletal maturity assessment in children with LCPD varies according to the utilized maturity system. The Optimized Oxford bone age more closely mirrors the patient's CA and does not correlate with the GP bone age, which reveals a delayed maturation.
Effects of Perioperative Teriparatide Treatment on the Hounsfield Unit Values at the Upper Instrumented Vertebra in Adult Spinal Deformity Surgery
Authors: Maruo Keishi , Arizumi Fumihiro , Kishima Kazuya , Yoshie Norichika , Kusukawa Tomoyuki , Tachibana Toshiya
Published: February 2023

Study Design:

Retrospective single-center study.

Objective:

This study aimed to assess the effects of pre and postoperative teriparatide (TPTD) treatment on Hounsfield units (HU) after surgery for adult spinal deformity (ASD).

Summary of Background Data:

The most commonly used method for assessing bone mineral density is dual-energy x-ray absorptiometry. HU values at the upper instrumented vertebra (UIV) have been proposed as a surrogate method for assessing bone quality, particularly in patients with ASD. However, the effect of TPTD treatment on vertebral HU values remains unclear.

Materials and Methods:

We identified 57 consecutive patients with ASD who underwent long-instrumented fusion surgery (>5 vertebrae) between 2014 and 2020. Patients were retrospectively divided into a non-TPTD group (n = 31) and a TPTD group (n = 26). HU measurements were obtained at a level above the UIV (UIV + 1). Changes in the HU value at 1-year postoperatively were compared between the TPTD and non-TPTD groups. The duration of preoperative TPTD was compared between the proximal junctional proximal junctional failure (PJF) and non-PJF groups.

Results:

Preoperative HU values were significantly lower in the TPTD group than in the non-TPTD group, despite no significant difference in preoperative bone mineral density of the proximal femur between the two groups. Changes in HU values were significantly higher in the TPTD group than in the non-TPTD group (20.8 ± 15.7% vs −2 ± 10.2%, P < 0.001). In the subanalysis of the TPTD group, the duration of preoperative TPTD treatment was significantly shorter in the PJF group than in the non-PJF group (34.7 ± 16.8 days vs 86.9 ± 34.7 days, P = 0.004).

Conclusions:

Pre and post-operative TPTD treatment increased the average HU value at UIV + 1 by 20.8%. Therefore, more prolonged preoperative TPTD treatment improves bone quality and may help prevent osteoporosis-related complications.
Rod Attachment Induces Significant Strain in Lumbosacral Fixation
Authors: Sawa Anna G.U. , Wangsawatwong Piyanat , Lehrman Jennifer N. , Hostetler Taylor , de Andrada Pereira Bernardo , Godzik Jakub , Hlubek Randall J. , Uribe Juan S. , Turner Jay D. , Kelly Brian P.
Published: February 2023

Study Design:

This was a laboratory investigation.

Objective:

Rod attachment can induce significant pedicle screw-and-rod pre-strain that may predispose the instrumentation to failure. This study investigated how in vitro L5–S1 rod strain and S1 screw strain during rod-screw attachment (pre-strain) compared with strains recorded during pure-moment bending (test-strain).

Summary of Background Data:

The lumbosacral junction is highly vulnerable to construct failure due to rod fatigue fracture, sacral screw pull-out, and screw fatigue fracture.

Materials and Methods:

Twelve cadaveric specimens were instrumented with L2–ilium pedicle screws and rod. Strain gauges on contoured rods and sacral screws recorded strains during sequential rod-to-screw tightening (pre-strains). The same instrumented constructs were immediately tested in a 6-degree-of-freedom apparatus under continuous loading to 7.5 Nm in multidirectional bending while recording instrumentation test-strains. Rod and screw pre-strains and test-strains were compared using 1-way repeated-measures analysis of variance followed by Holm-Šidák paired analysis (significant at P<0.05).

Results:

The mean first (171±192 µE) and second (322±269 µE) rod attachment pre-strains were comparable to mean test-strains during flexion (265±109 µE) and extension (315±125 µE, P≥0.13). The mean rod attachment pre-strain was significantly greater than mean test-strains during bidirectional lateral bending (40±32 µE ipsilateral and 39±32 µE contralateral, P<0.001) and axial rotation (72±60 µE ipsilateral and 60±57 µE contralateral, P<0.001). The mean first and second sacral screw pre-strains during rod attachment (1.03±0.66 and 1.39±1.00 Nm, respectively) did not differ significantly (P=0.41); however, the mean sacral screw pre-strain during final (second) rod attachment was significantly greater than screw test-strains during all directions of movement (≤0.81 Nm, P≤0.03).

Conclusions:

Instrumentation pre-strains imposed during in vitro rod-screw attachment of seemingly well-contoured rods in L2–ilium fixation are comparable to, and at times greater than, strains experienced during in vitro bending. Spine surgeons should be aware of the biomechanical consequences of rod contouring and attachment on construct vulnerability.
A Practical Statin Recommendation System Based on Real-World Data to Improve LDL-C Management in Secondary Prevention
Authors: Zhang Yunnan , Zhang Dalin , Liu Xinyu , Peng Wenxing , Mu Yu , Li Yuxin , Qiu Qi
Published: February 2023

Statins are considered the cornerstone of secondary prevention in patients with atherosclerotic cardiovascular disease (ASCVD). However, many patients fail to achieve the guide-recommended goal of low-density lipoprotein cholesterol (LDL-C) after statin monotherapy, leading to a high residual risk of cardiovascular events. Owing to individual differences in statin therapy, it is possible first to consider changing the type of statin before adding nonstatin medications in certain patients to improve LDL-C management. We developed and evaluated a statin recommendation system using real-world data. Ensemble learning was performed to develop the recommendation system that integrated the output results of support vector machines (SVM) and the similarity of patients. Model performance was assessed to investigate whether treatment according to the recommended model would increase the proportion of patients with the primary end point. Finally, a total of 3510 patients were enrolled in the development and validation of the recommender system. Of them, 1240 patients received atorvastatin (35.3%), 1714 patients received rosuvastatin (48.8%), and 556 patients received pitavastatin (15.8%). The statin recommendation system could significantly improve LDL-C target rate achievement in the recommended treatment group compared with the nonrecommended treatment group in the validation set (50.8% vs. 31.5%, P < 0.001). This study demonstrated that the statin recommendation system could significantly improve the achievement of LDL-C goals in ASCVD patients, providing a new approach to improve LDL-C management.
Impact of depression and antidepressant use on clinical outcomes of hepatitis B and C: a population-based study
Authors: Shaheen Abdel Aziz , Kaplan Gilaad G. , Sharkey Keith A. , Lethebe B. Cord , Swain Mark G.
Published: February 2023

Background:

Depression is common in patients with chronic viral hepatitis. We evaluated the impact of major depressive disorder (MDD) and antidepressant use on survival among patients with HBV and HCV.

Methods:

We used The Health Improvement Network database, the largest medical database in the UK, to identify incident HBV (n=1401) and HCV (n=1635) in patients between 1986 and 2017. Our primary composite outcome was the development of decompensated cirrhosis or death. MDD and each class of antidepressants were assessed in multivariate Cox proportional hazards models. Models were adjusted for age, sex, and clinical comorbidities.

Results:

The prevalence of MDD among HCV patients was higher compared with HBV patients (23.5% vs. 9.0%, p<0.001, respectively). Similarly, HCV patients were more likely to use antidepressants (59.6%) compared with HBV patients (27.1%), p>0.001. MDD was not an independent predictor for decompensated cirrhosis-free survival or mortality. However, the use of tricyclic and tetracyclic antidepressants (TCAs) was associated with poor decompensated cirrhosis-free survival in HBV and HCV cohorts (adjusted HR: 1.80, 95% CI, 1.00–3.26 and 1.56, 95% CI, 1.13–2.14, respectively). Both TCAs in the HBV cohort and selective serotonin reuptake inhibitors among the HCV cohort were associated with poor overall survival (adjusted HR: 2.18, 95% CI, 1.16–4.10; 1.48, 95% CI, 1.02–2.16, respectively).

Conclusions:

Although prevalent among viral hepatitis patients, MDD did not affect disease progression or survival in either HBV or HCV cohorts. TCA use was associated with poor decompensated cirrhosis-free survival. Therefore, its use should be further studied among viral hepatitis patients.