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"Xiang, L"
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Rural–Urban Educational Inequalities and Their Spatial Variations in China
Existing discussions of rural–urban education inequality focus primarily on education investment and/or attainment, with little attention being paid to the opportunities or potential that an area has to achieve better educational outcomes. This study presents a new analytical framework based on Amartya Sen’s capability approach for a better understanding of rural–urban education disparity. In addition, the rural–urban definitions for educational research are clarified and the effects of a wide range of Central Government policies aimed at reducing the rural–urban educational gap are assessed. The results suggest: inadequate investment (e.g., funding and high-quality teaching resources) in rural education in some regions, especially middle and high schools; inappropriate partitioning of the national territory by the Government for policy implementation; and negative effects resulting from the school consolidation policy. The latter will influence the ability of some rural areas to match the educational achievements of their urban counterparts. This research also reveals that the existing rural–urban gap will be unlikely to narrow under the current policy regime. A conventional approach based on investment and outcomes alone in rural–urban disparity research and policy may overlook the important interactions and conversion processes that are important for mitigating rural–urban disparities.
Journal Article
On High-frequency Kinetic Alfvén Waves in Space and Solar Plasma
Kinetic Alfvén waves (KAWs) are ubiquitous in space and solar plasmas and are believed to be crucial for energy transfer and particle energization. Existing studies on KAWs primarily focus on the low-frequency approximation, where the wave frequency is much smaller than the proton cyclotron frequency (i.e., ω ≪ ωcp). However, the wave properties of high-frequency KAWs with ω ≳ ωcp remain unclear. In this work, based on the two-fluid theory, we derive a general dispersion relation for KAWs spanning low-frequency to high-frequency regimes, and examine this dispersion relation and the electromagnetic properties of both low-frequency and high-frequency KAWs. Our findings reveal that, compared to low-frequency KAWs, high-frequency KAWs exhibit several distinct features: higher wave frequency (ω ≳ ωcp), propagation angle over a broader oblique angle range, significantly larger ratio of parallel to perpendicular electric field, and the magnetic helicity and magnetic compressibility that are highly sensitive to the plasma beta. The enhanced parallel electric field highlights the pivotal role of high-frequency KAWs in field-aligned particle acceleration. This work extends KAW theory to the high-frequency domain, providing key insights into KAW properties and the particle acceleration process in space and solar plasmas.
Journal Article
Triggered Emissions of Kinetic Alfvén Waves and Parallel Ion Cyclotron Waves by Ion Beam Mode in the Solar Wind
Kinetic Alfvén waves (KAWs) and ion cyclotron waves (ICWs) are believed to play a significant role in the solar wind heating and acceleration and are pervasive in space and astrophysical plasmas. However, the generation mechanism for the coexistence of both wave modes remains unclear. The present work proposes a novel generation scenario of KAWs and parallel ICWs in a homogeneous solar wind plasma using hybrid simulations. Our numerical study reveals that the emissions of KAWs and parallel ICWs can be triggered by the ion beam (IB) mode in a homogeneous alpha or proton beam plasma with a beam velocity of ≥1.2v A for alpha particles or ≥1.6v A for proton beams, where v A represents the local Alfvén velocity. The growth rates of both KAWs and parallel ICWs are significantly higher than that of the IB mode. Moreover, the initial background proton beta exhibits an inverse correlation with the growth of KAWs. Ultimately, the saturation energy of these triggered emissions could rival that of the IB mode. Given the prevalent occurrence of IBs in the solar wind, this triggering process provides a credible explanation for the origin of KAWs and parallel ICWs and their coexistence within the beam plasma environments.
Journal Article
Super-X and conventional divertor configurations in MAST-U ohmic L-mode; a comparison facilitated by interpretative modelling
Measurements are presented, alongside corresponding interpretative SOLPS-ITER simulations, of the first MAST-U experiments comparing ohmically heated L-mode fuelling scans in Conventional divertor (CD) and Super-X divertor (SXD) configurations. In experiment, at comparable outer mid-plane separatrix electron density, ne,sep,OMP , the maximum lower outer target heat load was found to be a factor 16 ±7 lower in SXD compared to CD. In simulation, a factor 26.8 reduction was found (slightly higher than the experimental range), suggesting an additional reduction in SXD compared to the factor 9.3 expected from geometric considerations alone. According to the simulations, this additional reduction in the SXD is due to a net radial transport of the energy remaining downstream of the Te=5 eV location. This energy is carried out of the critical (highest heat load) flux tube by deuterium atoms, demonstrating the importance of a longer legged divertor which provides space for this to occur. Importantly, in both simulation and experiment, the SXD has minimal impact on the upstream ne and Te profiles. Spectral inferences of detachment front movement in SXD compare well between simulation and experiment. In regions of high magnetic field gradient, the parallel movement of the front towards the X-point becomes less sensitive to increasing ne,sep,OMP , in qualitative agreement with simplified models and previous predictive simulations. Additional aspects, regarding the target ion flux rollover, upstream separatrix temperature and drift effects, are also presented and discussed.
Journal Article
Instabilities Driven by Proton Temperature Anisotropy in the Presence of Alpha Particles: Implications for Proton-temperature-anisotropy Constraint in the Solar Wind
In situ measurements reveal that proton temperature anisotropy is ubiquitous in the solar wind. Various plasma instabilities have been proposed to regulate the distribution of the proton temperature anisotropy in the solar wind; detailed constraint processes are still unclear. In this paper, we study the effects of alpha beams on both the forward and backward proton temperature anisotropy instabilities at parallel and oblique propagation with the Vlasov theory, and compare the theoretical results with the Wind observation. As the alpha-beam drift velocity v α /v A increases, the growth rates of forward Alfvén/ion-cyclotron (FA/IC) and backward magnetosonic/whistler (BM/W) instabilities increase, those of backward Alfvén/ion-cyclotron (BA/IC) and forward magnetosonic/whistler (FM/W) instabilities decrease, and those of the mirror and forward Alfvén wave (FAW) instabilities are nearly constant. In particular, there are different constraining mechanisms on the distribution of proton temperature anisotropy for different values of the alpha-beam drift velocity. The proton temperature anisotropy instability together with the alpha beam can provide a potential explanation for the distribution of the proton temperature anisotropy in the solar wind.
Journal Article
The Opposite Behaviors of Proton and Electron Temperatures in Relation to Solar Wind Magnetic Energy: Parker Solar Probe Observations
Solar wind heating is an outstanding issue that has been discussed for decades. Research on the connection between solar wind particle temperatures and turbulence may provide insight into this issue. Based on Parker Solar Probe observations, this paper investigates the properties of solar wind proton and electron temperatures in relation to turbulent magnetic energy, via the calculation of correlation coefficients (CCs) between particle temperatures and magnetic energy. The calculations are regulated by the spatial scale, plasma beta (β), and the angle between the solar wind velocity and background magnetic field, where the plasma beta is the ratio of plasma thermal to magnetic pressure. Results show that the correlation between proton temperature and magnetic energy is positive and can be strong with a CC exceeding 0.8. The strong correlation preferentially occurs at ion scales, with the wind velocity and background magnetic field quasi-perpendicular and over a wide beta range (β < 3.0). On the other hand, the correlation between electron temperature and magnetic energy is commonly negative, often with an intermediate or negligible CC, accordingly. The CC with an amplitude up to 0.8 can arise at larger scales with the wind velocity and background magnetic field quasi-(anti)parallel and in the low-beta case (β < 0.6). The implication of these findings on the physics of turbulent heating in the solar wind is discussed.
Journal Article
Factors Associated with Non-Adherence to Treatment Among Migrants with MDR-TB in Wuhan, China: A Cross-Sectional Study
Multidrug resistant tuberculosis (MDR-TB) has attracted increasing attention in achieving the global goal of tuberculosis (TB) control. China has the second largest TB burden worldwide and has been experiencing large-scale domestic migration. This study aims to explore the effect of migrants on non-adherence to MDR-TB treatment.
A cross-sectional study was carried out in Wuhan, China. The exposure cases were migrants who were not locally registered in the residence registration system. The control cases were local residents. Non-adherence cases were patients who were lost follow-up or refused treatment. Chi-square and
-test were used to compare variables between migrants and local residents. Logistic regression models using enter method were used to determine the relationship between migration and non-adherence to treatment. Moderation and medication effects on the association between migrant status and non-adherence were also explored.
We studied 73 migrants and 219 local residents. The migrants, who did not to adhere to treatment (55, 75.3%), was far higher than that of local residents (89, 40.6%). Migrants with MDR-TB had 10.38-times higher difficulty in adhering to treatment (adjusted OR = 10.38, 95% CI 4.62-25.28) than local residents. This additional likelihood was moderated by age and treatment registration group. Migration had an indirect association with non-adherence to treatment via social medial insurance (adjusted OR = 1.05, 95% CI 1.01-1.13).
There a significant increased likelihood of non-adherence to treatment among migrants with MDR-TB, highlighting the importance of improving treatment adherence in this population. Migration prevented migrants from gaining access to social medical insurance and indirectly reduced their likelihood of adherence to treatment.
Journal Article
An overview of the STEP divertor design and the simple models driving the plasma exhaust scenario
This paper presents a comprehensive overview of the preliminary divertor design and plasma exhaust scenario for the reactor-class Spherical Tokamak for Energy Production project. Due to the smaller size of the machine, with a major radius less than half that of most DEMO concepts, the current design features a double-null divertor geometry, comprising tightly baffled extended outer legs and shorter inner legs approaching an X-divertor. Leveraging a significant database of SOLPS-ITER simulations, the exhaust operational space is mapped out, offering valuable insights into the plasma exhaust dynamics. An approach involving the validation of simple, yet robust models capable of accurately predicting key exhaust parameters is detailed, thereby streamlining the design process. The simple models are used to simulate the entire plasma scenario from the plasma current ramp-up, through the burning phase, to the plasma current ramp-down. Notably, the findings suggest that pronounced detachment, with peak heat loads below engineering limits and electron temperatures below 5 eV, is achievable with a divertor neutral pressure between 10 Pa and 15 Pa during the burning phase, and pressures below 5 Pa during the ramp-up to maximise the auxiliary current-drive efficiency. Throughout the scenario, an Ar concentration of ≈3% in the scrape-off layer (SOL) is required, in combination with a core radiation fraction of 70% driven by intrinsic emission and extrinsic injection of Xe seeded fuelling pellets. However, significant uncertainties remain regarding key parameters such as the SOL heat flux width, Ar screening, and plasma kinetic effects.
Journal Article
The Effects of the Multi-Hospital Global Budget Payment on Medical Expenditure and Service Volume: The Evidence from Dangyang County, China
Global budget payment is currently the prevailing payment strategy internationally. In China, the concept of multi-hospital global budget payment has been proposed with the aims of achieving cost control effects while also encouraging hospital collaboration and optimising allocation of healthcare resources. This study seeks to analyse the impact of multi-hospital global budget payment in China on healthcare expenditure and service volume.
A retrospective comparative study was carried out in Dangyang County, China. The exposure cases were migrants who were not locally registered in the residence registration system. The study period encompassed January 1, 2017, to December 31, 2019. Including 3,246,164 outpatient medical records and 242,685 inpatient medical records. The key variables are medical expenditure and service volume indicators. Continuous variables were reported as mean and tested by
-test. We used interrupted time series analysis models to estimate the changes in the level and trend of each outcome measure after the policy.
After the outpatient global budget payment reform, the monthly medical expenditure of the hospital alliance has transitioned from a discernible upward trajectory to a deceleration in the rate of growth. The outpatient volume in public and private high-level hospitals decreased at a rate of -419.26 person/month and -137.04 person/month, respectively. In terms of inpatient service volume, only private high-level hospitals reported a decrease, with a reduction rate of -15.38 individuals per month.
This study presents new evidence demonstrating that the multi-hospital global budget payment can effectively control costs and promote resource reallocation when implemented jointly with hospital alliance policies. However, overly lenient budget caps risk counterproductive effects.
Journal Article