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Ultra-thin liquid sheets generated by impinging two liquid jets are crucial high-repetition-rate targets for laser ion acceleration and ultra-fast physics, and serve widely as barrier-free samples for structural biochemistry. The impact of liquid viscosity on sheet thickness should be comprehended fully to exploit its potential. Here, we demonstrate experimentally that viscosity significantly influences thickness distribution, while surface tension primarily governs shape. We propose a thickness model based on momentum exchange and mass transport within the radial flow, which agrees well with the experiments. These results provide deeper insights into the behaviour of liquid sheets and enable accurate thickness control for various applications, including atomization nozzles and laser-driven particle sources.
The double-cone ignition scheme is a promising novel ignition method, which is expected to greatly save the driver energy and enhance the robustness of the implosion process. In this paper, ablation of the inner surface of the cone by the hard X-ray from coronal Au plasma is studied via radiation hydrodynamics simulations. It is found that the X-ray ablation of the inner wall will form strong pre-plasma, which will significantly affect the implosion process and cause the Au plasma to mix with the fuel, leading to ignition failure. The radiation and pre-ablation intensities in the system are estimated, and the evolutions of areal density, ion temperature and the distribution of Au ions are analysed. In addition, the mixing of Au in CH at collision is quantified. Then, a scheme to reduce the X-ray pre-ablation by replacing the gold cone with a tungsten cone is proposed, showing that it is effective in reducing high-Z mixing and improving collision results.
A high-energy picosecond 355 nm ultraviolet (UV) laser operating at 100 Hz was demonstrated. A 352 mJ, 69 ps, 1064 nm laser at 100 Hz was realized firstly by cascaded regenerative, laser diode end-pumped single-pass and side-pumped main amplifiers. The stimulated Raman scattering-based beam shaping technique, thermally induced birefringence compensation and 4f spatial filter-image relaying systems were used to maintain a relatively homogeneous beam intensity distribution during the amplification process. By using lithium triborate crystals for second- and third-harmonic generation (THG), a 172 mJ, approximately 56 ps, 355 nm UV laser was achieved with a THG conversion efficiency of 49%. To the best of our knowledge, it is the highest pulse energy of a picosecond 355 nm UV laser so far. The beam quality factor ${M}^2$ and pulse energy stability were ${M}_x^2$=3.92, ${M}_y^2$=3.71 and root mean square of 1.48%@3 hours. This laser system could play significant roles in applications including photoconductive switch excitation, laser drilling and laser micro-fabrication.
Despite extensive research into the neural basis of autism spectrum disorder (ASD), the presence of substantial biological and clinical heterogeneity among diagnosed individuals remains a major barrier. Commonly used case‒control designs assume homogeneity among subjects, which limits their ability to identify biological heterogeneity, while normative modeling pinpoints deviations from typical functional network development at individual level.
Methods
Using a world-wide multi-site database known as Autism Brain Imaging Data Exchange, we analyzed individuals with ASD and typically developed (TD) controls (total n = 1218) aged 5–40 years, generating individualized whole-brain network functional connectivity (FC) maps of age-related atypicality in ASD. We then used local polynomial regression to estimate a networkwise normative model of development and explored correlations between ASD symptoms and brain networks.
Results
We identified a subset exhibiting highly atypical individual-level FC, exceeding 2 standard deviation from the normative value. We also identified clinically relevant networks (mainly default mode network) at cohort level, since the outlier rates decreased with age in TD participants, but increased in those with autism. Moreover, deviations were linked to severity of repetitive behaviors and social communication symptoms.
Conclusions
Individuals with ASD exhibit distinct, highly individualized trajectories of brain functional network development. In addition, distinct developmental trajectories were observed among ASD and TD individuals, suggesting that it may be challenging to identify true differences in network characteristics by comparing young children with ASD to their TD peers. This study enhances understanding of the biological heterogeneity of the disorder and can inform precision medicine.
Amid China-US geopolitical competition in the Asia-Pacific, it is imperative for both China and Singapore to adapt and respond to evolving circumstances for mutual benefit.
The enduring trust and solid foundation between China and Singapore in economic and trade cooperation are validated through their active involvement in each other's initiatives. This proved true even when the recent COVID-19 pandemic strained political interactions.
The political-security dimensions of the relationship between China and Singapore are complex and constantly evolving, influenced as they are by factors such as Singapore's military training in Taiwan, the contentious South China Sea disputes, and US foreign policy in the region.
However, Singapore's longstanding hedging strategy between the two superpowers may face increasingly severe tests as China-US rivalry escalates.
If carefully managed, Singapore's successful track record of facilitating dialogue between conflicting parties can continue to make it a valuable player in easing tensions between China and the US.
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.
Binary nanodroplet collisions have received increasing attention, whilst the identification of collision outcomes and the viscous dissipation mechanism have remained poorly understood. Using molecular dynamics simulations, this study investigates binary nanodroplet collisions over wide ranges of Weber number (We), Ohnesorge number (Oh) and off-centre distances. Coalescence, stretching separation and shattering are identified; however, bouncing, reflexive separation and rotational separation reported for millimetre-sized collisions are not observed, which is attributed to the enhanced viscous effect caused by the ‘natural’ high-viscosity characteristics of nanodroplets. Intriguingly, as an intermediate outcome, holes form in retracting films at relatively high We, arising from the vibration and thermal fluctuation of the films. Due to the combined effects of inertial, capillary and viscous forces, binary nanodroplet collisions fall into the cross-over regime, so estimating viscous dissipation becomes extremely important for distinguishing outcome boundaries. Based on the criterion that stretching separation is triggered only when the residual off-centre kinetic energy exceeds the surface energy required for separation, the boundary equation between coalescence and stretching separation is established. Here, viscous dissipation is calculated by the extracted flow feature from simulations, showing that the ratio of viscous dissipation to the initial kinetic energy depends only on Oh, not on We. Because of complex viscous dissipation mechanisms, the same boundary equation in the cross-over regime has also not been satisfactorily revealed for macroscale collisions. Therefore, the proposed equation is tested for wide data sources from both macroscale and nanoscale collisions, and satisfying agreement is achieved, demonstrating the universality of the equation.
Beam–target reactions in fusion plasmas play an important role in both magnetic confinement fusion and inertial confinement fusion in the condition of low-density plasmas with high-velocity interactions. The traditional method for calculating beam–target reaction rate neglects the transport process of incident particles in inhomogeneous plasmas, leading to errors providing that the temperature and density in the transport path of incident particles vary obviously. An improved method considering the transport process is proposed in this paper to eliminate the deficiencies. Then the method is employed in high-speed plasma collision studies. When the initial plasma density and temperature are set to $0.5\,{\rm g}\,{\rm cm}^{-3}$ and 100 eV, it is found that the beam–target reaction rate calculated by the traditional method is almost identical to that by our method if the collision velocity is less than 600 km s$^{-1}$. However, the traditional method is not suitable for study as the collision velocity gets higher, inducing obvious differences, which can reach 70 % at 1000 km s$^{-1}$. The improved method will make large corrections to evaluate the importance of the non-negligible beam–target reaction for inertial confinement fusion schemes with large implosion velocity such as double-cone ignition and impact ignition, in which the high-speed plasmas collide with each other to realize plasma ignition.
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.
China-Singapore relations have come a long way since diplomatic ties were established in 1990. At that time, China needed friends and foreign investments, and Singapore played a role in befriending Beijing and bringing in investments from abroad. The West had then ostracized Beijing due to the 1989 Tiananmen incident. Today, a much stronger China faces a somewhat similar hostile external environment. Most notable is the escalating tensions between China and the United States, which has created a unique geopolitical context that necessitates a careful examination of the future trajectory of China-Singapore ties. As both nations navigate this complex geopolitical environment, they must adapt and respond to evolving circumstances so that they can continue to reap mutual benefits.
The strong and dynamic economic relationship between China and Singapore is well-known. This article will delve into the political-security dimensions of their bilateral ties by examining three issues, i.e., the South China Sea issue, Singapore’s relationship with the US, and the Taiwan issue. The paper argues that Singapore’s position on these three issues will need to be adjusted as China grows more powerful, and given the intensifying China-US competition in Asia. Such an adjustment will help ensure that China-Singapore ties have ample room to grow and flourish. The article will first trace how Chinese narratives on Singapore have evolved over the years and how these will continue to be shaped by Singapore’s stand on the above three issues.
NARRATIVES ON SINGAPORE’s ROLE IN CHINA’s DEVELOPMENT
The resilience of China-Singapore ties has been consistently demonstrated over the past few years, even when the COVID-19 pandemic strained political and economic interactions. Zhai Kun, a distinguished scholar in international relations at Peking University, notes that amongst all Southeast Asian nations, Singapore has been deeply involved in China’s reform and opening-up journey, and the city-state shares very close alignment with Chinese interests. This viewpoint primarily underscores the strong foundation for cooperation between China and Singapore in the economic arena, such as in trade, finance and technological exchanges. Singapore’s standing as the world’s largest offshore trading centre for renminbi (RMB) and a Southeast Asian nexus for China’s Belt and Road Initiative (BRI) reinforce this congruence of interests.
Viewed through the lens of economic and trade collaboration, China is Singapore’s prime trading partner, export market, and the most substantial source of imports.
Constraining the timing and extent of Quaternary glaciations in the Tibetan Plateau (TP) is significant for the reconstruction of paleoclimatic environment and understanding the interrelationships among climate, tectonics, and glacial systems. We investigated the late Quaternary glacial history of the Qinggulong and Juequ valleys in the Taniantaweng Mountains, southeastern TP, using cosmogenic 10Be surface exposure dating. Four major glacial events were identified based on 26 10Be ages. The exposure ages of the oldest late Quaternary glaciation correspond to Marine Oxygen Isotope Stage (MIS) 6. The maximum glacial extent was dated to 48.5–41.1 ka (MIS 3), during the last glaciation, and was more advanced than that of the last glacial maximum (LGM). Geochronology and geomorphological evidence indicate that multiple glacial fluctuations occurred in the study area during the Early–Middle Holocene. These glacial fluctuations likely were driven by the North Atlantic climate oscillations, summer solar insolation variability, Asian summer monsoon intensity, and CO2 concentration.
• Amid China-US geopolitical competition in the Asia-Pacific, it is imperative for both China and Singapore to adapt and respond to evolving circumstances for mutual benefit.
• The enduring trust and solid foundation between China and Singapore in economic and trade cooperation are validated through their active involvement in each other’s initiatives. This proved true even when the recent COVID-19 pandemic strained political interactions.
• The political-security dimensions of the relationship between China and Singapore are complex and constantly evolving, influenced as they are by factors such as Singapore’s military training in Taiwan, the contentious South China Sea disputes, and US foreign policy in the region.
• However, Singapore’s longstanding hedging strategy between the two superpowers may face increasingly severe tests as China-US rivalry escalates.
• If carefully managed, Singapore’s successful track record of facilitating dialogue between conflicting parties can continue to make it a valuable player in easing tensions between China and the US.
Let $\mathcal {M}$ be an Ahlfors $n$-regular Riemannian manifold such that either the Ricci curvature is non-negative or the Ricci curvature is bounded from below together with a bound on the gradient of the heat kernel. In the paper [IMRN, 2022, no. 2, 1245-1269] of Brazke–Schikorra–Sire, the authors characterised the BMO function $u : \mathcal {M} \to \mathbb {R}$ by a Carleson measure condition of its $\sigma$-harmonic extension $U:\mathcal {M}\times \mathbb {R}_+ \to \mathbb {R}$. This paper is concerned with the similar problem under a more general Dirichlet metric measure space setting, and the limiting behaviours of BMO & Carleson measure, where the heat kernel admits only the so-called diagonal upper estimate. More significantly, without the Ricci curvature condition, we relax the Ahlfors regularity to a doubling property, and remove the pointwise bound on the gradient of the heat kernel. Some similar results for the Lipschitz function are also given, and two open problems related to our main result are considered.
Little is known about how sociodemographic and clinical factors affect the caregiving burden of persons with schizophrenia (PwSs) with transition in primary caregivers.
Aims
This study aimed to examine the predictive effects of sociodemographic and clinical factors on the caregiving burden of PwSs with and without caregiver transition from 1994 to 2015 in rural China.
Method
Using panel data, 206 dyads of PwSs and their primary caregivers were investigated in both 1994 and 2015. The generalised linear model approach was used to examine the predictive effects of sociodemographic factors, severity of symptoms and changes in social functioning on the caregiving burden with and without caregiver transition.
Results
The percentages of families with and without caregiver transition were 38.8% and 61.2%, respectively. Among families without caregiver transition, a heavier burden was significantly related to a larger family size and more severe symptoms in PwSs. Deteriorated functioning of ‘social activities outside the household’ and improved functioning of ‘activity in the household’ were protective factors against a heavy caregiving burden. Among families with caregiver transition, younger age, improved marital functioning, deteriorated self-care functioning, and better functioning of ‘social interest or concern’ were significant risk factors for caregiving burden.
Conclusions
The effects of sociodemographic and clinical correlates on the caregiving burden were different among families with and without caregiver transition. It is crucial to explore the caregiver arrangement of PwSs and the risk factors for burden over time, which will facilitate culture-specific family interventions, community-based mental health services and recovery.
Current studies on inhibitory effects of n-3 PUFA on pro-inflammatory cytokines have inconsistent results. Thus, a meta-analysis of randomised controlled trials was conducted to identify the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer. Studies that examined the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer were identified by searching PubMed and EMBASE from January 1975 to February 2021. Differences in n-3 PUFA administration and control conditions were determined by calculating standardised mean differences (SMD) with 95 % CI. Twenty studies involving 971 patients met the inclusion criteria. The overall SMD were 0·485 (95 % CI 0·087, 0·883) for IL-6 and 0·712 (95 % CI 0·461, 0·962) for TNF between n-3 PUFA administration and control conditions. Sources of heterogeneity were not found through subgroup and meta-regression analyses. Publication bias was observed in TNF with a slight contribution to the effect size. n-3 PUFA can reduce circulating IL-6 and TNF levels in patients with cancer. Results supported the recommendation of n-3 PUFA as adjuvant therapy for patients with cancer, possibly excluding head and neck cancer, owing to their anti-inflammatory properties.
Listeriosis is a rare but serious foodborne disease caused by Listeria monocytogenes. This matched case–control study (1:1 ratio) aimed to identify the risk factors associated with food consumption and food-handling habits for the occurrence of sporadic listeriosis in Beijing, China. Cases were defined as patients from whom Listeria was isolated, in addition to the presence of symptoms, including fever, bacteraemia, sepsis and other clinical manifestations corresponding to listeriosis, which were reported via the Beijing Foodborne Disease Surveillance System. Basic patient information and possible risk factors associated with food consumption and food-handling habits were collected through face-to-face interviews. One hundred and six cases were enrolled from 1 January 2018 to 31 December 2020, including 52 perinatal cases and 54 non-perinatal cases. In the non-perinatal group, the consumption of Chinese cold dishes increased the risk of infection by 3.43-fold (95% confidence interval 1.27–9.25, χ2 = 5.92, P = 0.02). In the perinatal group, the risk of infection reduced by 95.2% when raw and cooked foods were well-separated (χ2 = 5.11, P = 0.02). These findings provide important scientific evidence for preventing infection by L. monocytogenes and improving the dissemination of advice regarding food safety for vulnerable populations.
The Lochkovian (Lower Devonian) conodont biostratigraphy in China is poorly known, and conodont-based subdivision schemes for the Lochkovian in peri-Gondwana (the Spanish Central Pyrenees, the Prague Synform, Sardinia, and the Carnic Alps) have not been tested in China. Therefore, we studied conodonts from the lower part (Bed 9 to Bed 13) of the Shanjiang Formation at the Alengchu section of Lijiang, western Yunnan to test the application of established subdivision schemes. The conodont fauna is assignable to 12 taxa belonging to eight genera (Ancyrodelloides, Flajsella, Lanea, Wurmiella, Zieglerodina, Caudicriodus, Pelekysgnathus, and Pseudooneotodus), and enables recognition of two chronostratigraphical intervals from the lower part of the Shanjiang Formation. The interval ranging from the uppermost part of Bed 9 to the upper part of Bed 10 belongs to the lower Lochkovian; whereas an interval covering the uppermost part of Bed 11 to the upper part of Bed 13 is correlated with the upper half of the middle Lochkovian. The Silurian-Devonian boundary is probably located within Bed 9, in the basal part of the Shanjiang Formation. However, the scarcity of specimens precludes definitive identification of bases of the lower, middle, and upper Lochkovian as well as other conodont zones recognized in peri-Gondwana.
Stable isotope ratios (δ18O and δD) in Antarctic snow and ice are basic proxy indices of climate in ice core studies. The relation between the ratios has important indicative significance for moisture sources. In general, the fractionation characteristics of the two isotopes vary with different meteorological and topographical conditions. This paper presents the spatial and temporal distribution of meteoric water line (MWL) slopes along a traverse from the Zhongshan Station (ZSS) to Dome A in East Antarctica. It is found that the slopes decrease with the increasing distance inland from the coast and the lowest slope occurred at Dome A, where the long-range transported moisture dominates and clear sky snowing have an influence. The slopes in different layers of the snowpack showed a decreasing trend with depth and this is attributed to the fractionation during the interstitial sublimation and re-condensation processes of the water vapor. Frost flower development on the interior plateau surface can greatly alter the depth evolution of the MWL slope. The coastal snow pits also go through the post-depositional smoothing effect, but their influences are not so significant as the inland regions.
Examine mother–son, mother–daughter, father–son and father–daughter resemblance in weight status, and potential modifying effects of socio-demographic and childcare characteristics.
Design:
Cross-sectional study.
Setting:
School.
Participants:
1973 school-age children and their parents from five mega-cities across China in 2017.
Results:
Pearson correlation coefficients (r) for BMI of father–son, father–daughter, mother–son and mother–daughter pairs were 0·16, 0·24, 0·26 and 0·24, respectively, while their weighted kappa coefficients (k) were 0·09, 0·14, 0·04 and 0·15, respectively. Children aged 6–9 years (r ranged from 0·30 to 0·35) had larger BMI correlation with their parents than their counterparts aged 10–14 years or 15–17 years (r ranged from 0·15 to 0·24). Children residing at home (r ranged from 0·17 to 0·27) had greater BMI correlations with their parents than children residing at school/other places. BMI correlation coefficients were significant if children were mainly cared for by their mothers (r ranged from 0·17 to 0·29) but non-significant if they were mainly cared for by others. Only children who ate the same meal as their parents ‘most times’ (r ranged from 0·17 to 0·27) or had dinner with their parents ‘at most times’ (r ranged from 0·21 to 0·27) had significant BMI correlation with their parents. Similarly, children who had dinner with their parents ‘most times’ but not ‘sometimes,’ had significant BMI correlation coefficients.
Conclusions:
Parent–child resemblance in weight status was modest and varied by child age, gender, primary caregiver, whether having similar food or dinner with parents in China.