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This study employs direct numerical simulations to examine the effects of varying backpressure conditions on the turbulent atomisation of impinging liquid jets. Using the incompressible Navier–Stokes equations, and a volume-of-fluid approach enhanced by adaptive mesh refinement and an isoface-based interface reconstruction algorithm, we analyse spray characteristics in the environments with ambient gas densities ranging from 1 to 40 times the atmospheric pressure under five different backpressure scenarios. We investigate the behaviour of turbulent jets, incorporate realistic orifice geometries and identify significant variations in the atomisation patterns depending on backpressure. Two distinct atomisation types emerge, namely jet-sheet-ligament-droplet at lower backpressures and jet-sheet-fragment-droplet at higher ones, alongside a transition from dilute to dense spray patterns. This variation affects the droplet size distribution and spray dynamics, with increased backpressure reducing the spray's spreading angle and breakup length, while increasing the droplet size variation. Furthermore, these conditions promote distributions that induce rapid, nonlinear wavy motion in liquid sheets. Topological analysis of the atomisation field using velocity-gradient tensor invariants reveals significant variations in topology volume fractions across different regions. Downstream, the droplet Sauter mean diameter increases and then stabilises, reflecting the continuous breakup and coalescence processes, notably under higher backpressures. This research underscores the substantial impact of backpressure on impinging-jet atomisation and provides essential insights for nozzle design to optimise droplet distributions.
Based on monthly panel data from 2014 to 2020 and employing the staggered difference-in-differences (staggered DID) method, we examine the impact of environmental vertical management reform on data manipulation in the public sector. We reveal that environmental vertical management reform significantly reduces data manipulation in the public sector. Moderating effect analysis shows that economic growth targets weaken the inhibitory impact of this reform. Conversely, public environmental concerns could enhance the inhibitory impact of this reform on data manipulation. Mechanism analysis reveals that environmental vertical management reform works through strengthening grassroots environmental law enforcement. The increased independence of law-enforcing departments has reduced the tendency of local governments to engage in data manipulation.
The large number of patients with ankle injuries and the high incidence make ankle rehabilitation an urgent health problem. However, there is a certain degree of difference between the motion of most ankle rehabilitation robots and the actual axis of the human ankle. To achieve more precise ankle joint rehabilitation training, this paper proposes a novel 3-PUU/R parallel ankle rehabilitation mechanism that integrates with the human ankle joint axis. Moreover, it provides comprehensive ankle joint motion necessary for effective rehabilitation. The mechanism has four degrees of freedom (DOFs), enabling plantarflexion/dorsiflexion, eversion/inversion, internal rotation/external rotation, and dorsal extension of the ankle joint. First, based on the DOFs of the human ankle joint and the variation pattern of the joint axes, a 3-PUU/R parallel ankle joint rehabilitation mechanism is designed. Based on the screw theory, the inverse kinematics inverse, complete Jacobian matrix, singular characteristics, and workspace analysis of the mechanism are conducted. Subsequently, the motion performance of the mechanism is analyzed based on the motion/force transmission indices and the constraint indices. Then, the performance of the mechanism is optimized according to human physiological characteristics, with the motion/force transmission ratio and workspace range as optimization objectives. Finally, a physical prototype of the proposed robot was developed, and experimental tests were performed to evaluate the above performance of the proposed robot. This study provides a good prospect for improving the comfort and safety of ankle joint rehabilitation from the perspective of human-machine axis matching.
Fast radio bursts (FRBs) are millisecond-duration radio waves from the Universe. Even though more than 50 physical models have been proposed, the origin and physical mechanism of FRB emissions are still unknown. The classification of FRBs is one of the primary approaches to understanding their mechanisms, but previous studies classified conventionally using only a few observational parameters, such as fluence and duration, which might be incomplete. To overcome this problem, we use an unsupervised machine-learning model, the Uniform Manifold Approximation and Projection to handle seven parameters simultaneously, including amplitude, linear temporal drift, time duration, central frequency, bandwidth, scaled energy, and fluence. We test the method for homogeneous 977 sub-bursts of FRB 20121102A detected by the Arecibo telescope. Our machine-learning analysis identified five distinct clusters, suggesting the possible existence of multiple different physical mechanisms responsible for the observed FRBs from the FRB 20121102A source. The geometry of the emission region and the propagation effect of FRB signals could also make such distinct clusters. This research will be a benchmark for future FRB classifications when dedicated radio telescopes such as the square kilometer array or Bustling Universe Radio Survey Telescope in Taiwan discover more FRBs than before.
Dietary n-3 PUFA may have potential benefits in preventing peptic ulcer disease (PUD). However, data from observational epidemiological studies are limited. Thus, we conducted a Mendelian randomisation analysis to reveal the causal impact of n-3 PUFA on PUD. Genetic variants strongly associated with plasma levels of total or individual n-3 PUFA including plant-derived α-linolenic acid and marine-derived EPA, DPA and DHA were enrolled as instrumental variables. Effect size estimates of the n-3 PUFA-associated genetic variants with PUD were evaluated using data from the UK biobank. Per one sd increase in the level of total n-3 PUFA in plasma was significantly associated with a lower risk of PUD (OR = 0·91; 95 % CI 0·85, 0·99; P = 0·020). The OR were 0·81 (95 % CI 0·67, 0·97) for EPA, 0·72 (95 % CI 0·58, 0·91) for DPA and 0·87 (95 % CI 0·80, 0·94) for DHA. Genetically predicted α-linolenic acid levels in plasma had no significant association with the risk of PUD (OR = 5·41; 95 % CI 0·70, 41·7). Genetically predicted plasma levels of n-3 PUFA were inversely associated with the risk of PUD, especially marine-based n-3 PUFA. Such findings may have offered an effective and feasible strategy for the primary prevention of PUD.
Sediments within accretionary complexes, preserving key information on crust growth history of Central Asian Orogenic Belt, did not get enough attention previously. Here, we conduct comprehensive geochemical study on the turbidites from the North Tianshan Accretionary Complex (NTAC) in the Chinese West Tianshan orogen, which is a good example of sediments derived from juvenile materials. The turbidites, composed of sandstone, siltstone, and argillaceous siliceous rocks, are mainly Carboniferous. All the investigated samples have relatively low Chemical Index of Alteration values (35–63) and Plagioclase Index of Alteration values (34–68), indicating relatively weak weathering before erosion and deposition. The sandstone and siltstone, and slate samples display high Index of Compositional Variability values of 0.89–1.50 and 0.89–0.93, suggesting a relatively immature source. The sandstones and siltstones were mainly derived from intermediate igneous rocks, and the slates from felsic igneous rocks, formed in oceanic/continental arc settings. The investigated samples roughly display high positive εNd(t) values (mainly at +5.5 to +7.9, except one spot at +0.8), with corresponding Nd model ages at 672 Ma–522 Ma (except one at ∼1.1 Ga). Combined with the previous studies, we suggest that the turbidites in the NTAC were mainly derived from intermediate to felsic igneous rocks with juvenile arc signature, and thus the northern Chinese West Tianshan is a typical site with significant Phanerozoic crust growth.
Previous studies suggest a link between vitamin D status and COVID-19 susceptibility in hospitalised patients. This study aimed to investigate whether vitamin D concentrations in elderly individuals were associated with their susceptibility to Omicron COVID-19 incidence, the severity of the disease and the likelihood of reoccurrence during the era of the post-‘zero-COVID-19’ policies in China.
Design:
In this retrospective study, participants were categorised into three groups based on their 25(OH)D concentrations: deficiency (< 20 ng/ml), insufficiency (20 to < 30 ng/ml) and sufficiency (≥ 30 ng/ml). The demographic and clinical characteristics, comorbidities and the incidence rate, reoccurrence rate and severity of Omicron COVID-19 were retrospectively recorded and analysed by using hospital information system data and an online questionnaire survey.
Setting:
China.
Participants:
222 participants aged 60 years or older from a health management centre.
Results:
Our findings revealed significant differences in the incidence (P = 0·03) and recurrent rate (P = 0·02) of Omicron COVID-19 among the three groups. Participants with lower 25(OH)D concentrations (< 20 ng/ml) exhibited higher rates of initial incidence and reoccurrence and a greater percentage of severe and critical cases. Conversely, individuals with 25(OH)D concentrations ≥ 30 ng/ml had a higher percentage of mild cases (P = 0·003). Binary and ordinal logistic regression models indicated that vitamin D supplementation was not a significant risk factor for COVID-19 outcomes.
Conclusions:
In the elderly population, pre-infection vitamin D deficiency was associated with increased susceptibility to incidence, severity of illness and reoccurrence rates of Omicron COVID-19.
The World Health Organization declared the current monkeypox outbreak a public health emergency of international concern (PHEIC) on July 23, 2022, as it has posed a great threat to human health. This bibliometric analysis aimed to explore the current research hotspots focused on monkeypox.
Methods
A systematic search of the Web of Science Core Collection database was conducted for published articles on monkeypox from database inception to February 23, 2023. VOSviewer software was used for analysis and visualization of research results.
Results
A total of 1646 publications on monkeypox virus were included for bibliometric analysis. Results showed that (1) the number of publications about monkeypox virus increased significantly in 2022, (2) smallpox and monkeypox virus were popular research keywords, (3) the United States has made the most significant contribution to the study of monkeypox virus, (4) Journal of Virology was the most active journal in publishing articles about monkeypox, and (5) research themes mainly included the body’s reaction after monkeypox infection, epidemiology, diagnosis, and pathological mechanisms.
Conclusions
Future research should focus on early sensitive diagnostic measures of monkeypox and the development of vaccines based on the characteristics of the virus. Study findings also provided key areas for public health experts to focus on and collaborate with policymakers.
Direct numerical simulations have been conducted to investigate turbulent Rayleigh– Bénard convection (RBC) of liquid metal in a cuboid vessel with aspect ratio $\varGamma =5$ under an imposed horizontal magnetic field. Flows with Prandtl number $Pr=0.033$, Rayleigh numbers ranging up to $Ra\leq 10^{7}$, and Chandrasekhar numbers up to $Q\leq 9 \times 10^6$ are considered. For weak magnetic fields, our findings reveal that a previously undiscovered decreasing region precedes the enhancement of heat transfer and kinetic energy. For moderate magnetic fields, we have reproduced the reversals of the large-scale flow, which are considered a reorganization process of the roll-like structures that were reported experimentally by Yanagisawa et al. (Phys. Rev. E, vol. 83, 2011, 036307). Nevertheless, the proposed approach of skewed-varicose instability has been substantiated as insufficient to elucidate fundamentally the phenomenon of flow reversal, an occurrence bearing a striking resemblance to the large-scale intermittency observed in magnetic channel flows. As we increase the magnetic field strength further, we observe that the energy dissipation of the system comes primarily from the viscous dissipation within the boundary layer. Consequently, the dependence of Reynolds number $Re$ on $Q$ approaches a scaling as $Re\,Pr/Ra^{2/3} \sim Q^{-1/3}$. At the same time, we find the law for the cutoff frequency that separates large quasi-two-dimensional scales from small three-dimensional ones in RBC flow, which scales with the interaction parameter as ${\sim }N^{1/3}$.
The Righi–Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh–Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-magnetohydrodynamic simulations. The perturbation structure gets into a low magnetization state though the peak strength of the self-generated magnetic field could reach hundreds of teslas. The Righi–Leduc effect plays an essential impact both in the linear and nonlinear stages, and it deflects the total heat flux towards the spike base. Compared to the case without the self-generated magnetic field included, less heat flux is concentrated at the spike tip, finally mitigating the ablative stabilization and leading to an increase in the velocity of the spike tip. It is shown that the linear growth rate is increased by about 10% and the amplitude during the nonlinear stage is increased by even more than 10% due to the feedback of the magnetic field, respectively. Our results reveal the importance of Righi–Leduc heat flux to the growth of the instability and promote deep understanding of the instability evolution together with the self-generated magnetic field, especially during the acceleration stage in inertial confinement fusion.
The laboratory generation and diagnosis of uniform near-critical-density (NCD) plasmas play critical roles in various studies and applications, such as fusion science, high energy density physics, astrophysics as well as relativistic electron beam generation. Here we successfully generated the quasistatic NCD plasma sample by heating a low-density tri-cellulose acetate (TCA) foam with the high-power-laser-driven hohlraum radiation. The temperature of the hohlraum is determined to be 20 eV by analyzing the spectra obtained with the transmission grating spectrometer. The single-order diffraction grating was employed to eliminate the high-order disturbance. The temperature of the heated foam is determined to be T = 16.8 ± 1.1 eV by analyzing the high-resolution spectra obtained with a flat-field grating spectrometer. The electron density of the heated foam is about under the reasonable assumption of constant mass density.
Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However, due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.
Edited by
Michael Bach, Institute for Research and Development on Inclusion and Society, Ontario and Toronto Metropolitan University,Nicolás Espejo-Yaksic, Exeter College, Oxford, Universiteit Leiden and University College Cork
This chapter reviews the normative framework of legal capacity in China‘s mainland. The primary focus includes China‘s adult guardianship system in the recently adopted Civil Code and the provisions from the first national Mental health Law (MHL) that authorise detention and involuntary treatment. This chapter defines legal capacity, the equal recognition of which is central to the spirit of the United Nations Convention on the Rights of Persons with Disabilities (CRPD or Convention), as boThthe capacity for having rights and the capacity for exercising rights. In China, as elsewhere, legal capacity, particularly the legal capacity of persons with intellectual disabilities and psychosocial disabilities, is denied through provisions for adult guardianship and the application of involuntary admission and treatment under Chinese non-criminal law. Following the adoption of the CRPD, the normative framework governing legal capacity has been subject to law reform, through which the respect for the autonomy of persons concerned has been strengthened. The chapter will outline the key points of this normative framework, with a view to highlighting the changes brought by the law reforms. It will also raise questions about the extent to which these changes have been translated into practice.
Before proceeding to a closer examination of the law regulating the exercise of legal capacity in China's mainland, we outline the approach that gives effect to CRPD Article 12 on legal capacity in this jurisdiction. Sections that follow discuss the law reforms related to the adult guardianship system in the Civil Code and the Mental health Law respectively. We conclude with a discussion on the implementation of such law reforms.
STATUS OF THE CONVENTION AT DOMESTIC LEVEL IN CHINA's MAINLAND
It is difficult to define whether the Chinese legal system, like most domestic legal systems, follows the theory of monism or dualism; therefore, the status of international treaties in the Chinese legal system is a very complex issue. There is not an explicit rule that prescribes the status, hierarchy, or effect of Article 12 in Chinese law. Before the ratification of the CRPD, China has been a party to all the core human rights conventions except for the International Covenant on Civil and Political Rights, which has not been ratified.
Sedimentary records from the Kumtag (also known as Kumtagh) Desert (KMD) in northwestern China are investigated to better understand Late Quaternary paleoenvironmental changes in this hyper-arid region. Presented here are the results of probably the first systematic survey of sedimentary sequences from the KMD, with the chronology determined by the optically stimulated luminescence dating. The variation of sedimentary facies, supported by granular and geochemical paleoenvironmental proxies, is used to decipher the history of Late Quaternary environment changes. The results demonstrate that a constantly dry condition characterized the eastern KMD since the last glacial maximum, but with occurrences of wetter periods. From ca. 17 to 15 ka, fluvial activity was probably triggered by melting of glaciers in mountains located south of the KMD. A distinctly drier stage (ca. 13–7 ka) was recognized due to the prominent occurrence of aeolian sands. A wetter environment likely persisted between ca. 4.4 and 2.2 ka, consistent with evidence of human activities. While the causes of paleoenvironmental changes in the eastern KMD are still a matter of debate, the melting of glaciers in the Altyn-Tagh Mountains in the south must be considered as an important factor.
Straightplasma channels are widely used to guide relativistic intense laser pulses over several Rayleigh lengths for laser wakefield acceleration. Recently, a curved plasma channel with gradually varied curvature was suggested to guide a fresh intense laser pulse and merge it into a straight channel for staged wakefield acceleration [Phys. Rev. Lett. 120, 154801 (2018)]. In this work, we report the generation of such a curved plasma channel from a discharged capillary. Both longitudinal and transverse density distributions of the plasma inside the channel were diagnosed by analyzing the discharging spectroscopy. Effects of the gas-filling mode, back pressure and discharging voltage on the plasma density distribution inside the specially designed capillary are studied. Experiments show that a longitudinally uniform and transversely parabolic plasma channel with a maximum channel depth of 47.5 μm and length of 3 cm can be produced, which is temporally stable enough for laser guiding. Using such a plasma channel, a laser pulse with duration of 30 fs has been successfully guided along the channel with the propagation direction bent by 10.4°.
The physics of leading-edge vortex (LEV) stability on flapping wings and autorotating seeds is still underexplored due to its complex dependency on Reynolds number ($\textit {Re}$), aspect ratio (AR) and Rossby number (Ro). Our previous study observed an interesting dual-stage vortex tilting between radial and tangential components in a stable LEV. Here, the establishment of this novel mechanism, i.e. dual-stage radial–tangential vortex tilting (DS-VT$_{r-t}$), is investigated and explained in detail using numerical methods. The contributions of other tangential vorticity transport terms are also considered. It is shown that the stable LEV region coincides mostly with a constant ratio of tangential and radial vorticity components. The DS-VT$_{r-t}$ mechanism functions as a negative feedback loop for radial vorticity, thereby contributing to the LEV stability at $\textit {Re} > 500$. Specifically, this mechanism involves a dual-stage vortex tilting starting from negative radial component to positive tangential component, and then back to positive radial component, thereby leading to a $180^{\circ }$ reversal of radial vorticity. The radial Coriolis acceleration can also assist the DS-VT$_{r-t}$ by enhancing the tangential vorticity component and the reduction of radial vorticity inside the LEV via the second stage of DS-VT$_{r-t}$. The effects of $\textit {Re}$, AR and Ro on the constant radial–tangential vorticity ratio and DS-VT$_{r-t}$ are then analysed. The coupled effects of AR and Ro are separated into rotational effects and those of tip and root vortices. Our results establish an evident relationship among the LEV stability, the constant radial–tangential vorticity ratio, and the DS-VT$_{r-t}$, thereby deepening the understanding in the vorticity transport of LEV formation and stability.
The Wood Snipe Gallinago nemoricola is one of the least known shorebird species, and its habitat associations are very poorly understood. Here we provide the first assessment of the habitat use of the Wood Snipe during the breeding season. Between May and July 2021 at a 4-km2 alpine meadow in Sichuan province, China, we conducted population surveys and behavioural observations to identify sites where breeding Wood Snipe occurred and foraged. We quantified the habitat characteristics and food resource availability of these sites and compared them with randomly selected “background” sites. Comparison between 34 occurrence sites and 25 background sites indicated that during the breeding season, Wood Snipes are not distributed evenly across alpine meadow habitats, but preferred habitats in the lower part (3,378–3,624 m) of the alpine meadow with intermediate levels of soil moisture. In addition, comparison between 17 foraging sites and 24 background sites showed that the Wood Snipe tended to forage at sites with higher soil fauna abundance. We found weak evidence for denser vegetation cover at its height and no evidence for other biotic habitat variables such as vegetation composition or other abiotic habitat variables such as slope, soil penetrability, or disturbance level to influence Wood Snipe habitat associations. Our results suggest that the actual distribution range of the Wood Snipe during the breeding season may be smaller than expected from the extent of apparently suitable habitat. We advise caution in evaluating the potential habitat availability and distribution of the Wood Snipe, and call for further research to better understand the ecology of this rare species to inform its conservation.
This chapter examines the current semi-normative framework for advance healthcare directives and related practice and discussion in China’s mainland. Without specified legislation acknowledging binding advance healthcare directives, China’s new Civil Code (2021) adopts legal criteria for a person to be deemed lacking in decision-making capacity and for the appointment of substitute decision makers for them. The Code of Ethics (2014) of the Chinese Medical Doctor Association requires Chinese medical practitioners to respect the expressed will of patients when they are capable of making decisions and to ensure patients’ maximum participation in the decision-making process even when they are considered to lack capacity. This chapter presents a doctrinal understanding of such a framework of norms that may potentially affect practices relating to advance healthcare directives. However, the existing evidence reflected by judicial proceedings and medical research papers suggests that the framework has rarely, if ever, been translated into medical practice. The chapter considers the possible legal and social explanations for such a lack of implementation. It also surveys a number of civil society-led pilot projects that promote advance healthcare directives, presenting a wider landscape of the relevant practice in China’s mainland.
The Nanjing Bao'ensi site is the largest and highest-ranking royal temple from the Ming Dynasty, and it is famous for its full-body glass pagoda. In this study, the glazed tiles excavated from the southern area of the Bao'ensi site were selected and analysed using X-ray diffraction, thermal dilation and energy-dispersive X-ray fluorescence to determine their phase composition, firing temperature and chemical composition. The glazed tile bodies of the Bao'ensi site consist mainly of quartz and mullite, although some samples contain trace amounts of other minerals. All of the body samples were fired to the same temperature range (i.e. 1000–1100°C). The firing temperature combined with the phase composition indicate that the raw materials and firing process of the glazed tile body samples have similarities, but there are certain differences. The source of the raw materials for a portion of the glazed tile bodies is Dangtu, Anhui, whilst the source of the raw materials for the remaining materials remains to be discovered.