Motion-induced radiation from electrons moving in Maxwell's fish-eye

In \u{C}erenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang {\itshape et al.}, we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of \u{C}erenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation.Comment: 17 pages, 8 figures, including the Supplementary Information appended in publication. Scientific Reports 201

Transition from ultrafast laser photo-electron emission to space charge limited current in a 1D gap

A one-dimensional (1D) model has been constructed to study the transition of the time-dependent ultrafast laser photo-electron emission from a flat metallic surface to the space charge limited (SCL) current, including the effect of non-equilibrium laser heating on metals at the ultrafast time scale. At a high laser field, it is found that the space charge effect cannot be ignored and the SCL current emission is reached at a lower value predicted by a short pulse SCL current model that assumed a time-independent emission process. The threshold of the laser field to reach the SCL regime is determined over a wide range of operating parameters. The calculated results agree well with particle-in-cell (PIC) simulation. It is found that the space charge effect is more important for materials with lower work function like tungsten (4.4 eV) as compared to gold (5.4 eV). However for a flat surface, both materials will reach the space charge limited regime at the sufficiently high laser field such as $>$ 5 GV/m with a laser pulse length of tens to one hundred femtoseconds.Comment: 12 pages, 3 figures, printed in {\itshape J. Phys. D: Appl. Phys.

Design of cycloidal rays in optical waveguides in analogy to the fastest descending problem

In this work, we present the design of cycloidal waveguides from a gradient refractive index (GRIN) medium in analogy to the fastest descending problem in classical mechanics. Light rays propagate along cycloids in this medium, of which the refractive index can be determined from relating to the descending speed under gravity force. It can be used as GRIN lenses or waveguides, and the frequency specific focusing and imaging properties have been discussed. The results suggest that the waveguide can be viewed as an optical filter. Its frequency response characteristics change with the refractive index profile and the device geometries.Comment: 10 pages, 6 figure

Three-dimensional bio-printing

Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing

AdaptGear: Accelerating GNN Training via Adaptive Subgraph-Level Kernels on GPUs

Graph neural networks (GNNs) are powerful tools for exploring and learning from graph structures and features. As such, achieving high-performance execution for GNNs becomes crucially important. Prior works have proposed to explore the sparsity (i.e., low density) in the input graph to accelerate GNNs, which uses the full-graph-level or block-level sparsity format. We show that they fail to balance the sparsity benefit and kernel execution efficiency. In this paper, we propose a novel system, referred to as AdaptGear, that addresses the challenge of optimizing GNNs performance by leveraging kernels tailored to the density characteristics at the subgraph level. Meanwhile, we also propose a method that dynamically chooses the optimal set of kernels for a given input graph. Our evaluation shows that AdaptGear can achieve a significant performance improvement, up to $6.49 \times$ ($1.87 \times$ on average), over the state-of-the-art works on two mainstream NVIDIA GPUs across various datasets

Wuqinxi qigong as an alternative exercise for improving risk factors associated with metabolic syndrome: A meta-analysis of randomized controlled trials

© 2019 by the authors. Background: The improvement of living standards has led to increases in the prevalence of hypokinetic diseases. In particular, multifactorial complex diseases, such as metabolic syndrome, are becoming more prevalent. Currently, developing effective methods to combat or prevent metabolic syndrome is of critical public health importance. Thus, we conducted a systematic review to evaluate the existing literature regarding the effects of Wuqinxi exercise on reducing risk factors related to metabolic syndrome. Methods: Both English- and Chinese-language databases were searched for randomized controlled trials investigating the effects of Wuqinxi on these outcomes. Meanwhile, we extracted usable data for computing pooled effect size estimates, along with the random-effects model. Results: The synthesized results showed positive effects of Wuqinxi exercise on systolic blood pressure (SBP, SMD = 0.62, 95% CI 0.38 to 0.85, p \u3c 0.001, I2 = 24.06%), diastolic blood pressure (DBP, SMD = 0.62, 95% CI 0.22 to 1.00, p \u3c 0.001, I2 = 61.28%), total plasma cholesterol (TC, SMD = 0.88, 95% CI 0.41 to 1.36, p \u3c 0.001, I2 = 78.71%), triglyceride (TG, SMD = 0.87, 95% CI 0.49 to 1.24, p \u3c 0.001, I2 = 67.22%), low-density lipoprotein cholesterol (LDL-C, SMD = 1.24, 95% CI 0.76 to 1.72, p \u3c 0.001, I2 = 78.27%), and high-density lipoprotein cholesterol (HDL, SMD = 0.95, 95% CI 0.43 to 1.46, p \u3c 0.001, I2 = 82.27%). In addition, regression results showed that longer-duration Wuqinxi intervention significantly improved DBP (β = 0.00016, Q = 5.72, df = 1, p = 0.02), TC (β = -0.00010, Q = 9.03, df = 1, p = 0.01), TG (β = 0.00012, Q = 6.23, df = 1, p = 0.01), and LDL (β = 0.00011, Q = 5.52, df = 1, p = 0.02). Conclusions: Wuqinxi may be an effective intervention to alleviate the cardiovascular disease risk factors of metabolic syndrome

Positive effects of parent–child group emotional regulation and resilience training on nonsuicidal self-injury behavior in adolescents: a quasi-experimental study

BackgroundNonsuicidal self-injury (NSSI) among adolescents is a growing global concern. However, effective interventions for treating NSSI are limited.MethodA 36-week quasi-experimental study design of parent–child group resilience training (intervention group) for adolescents aged 12–17 years was used and compared with treatment-as-usual (control group). The primary endpoint was the frequency of NSSI assessed with the Ottawa Self-Injury Inventory (OSI), and the secondary endpoints were the levels of depression, hope, resilience, and family adaptability and cohesion as assessed by the 24-item Hamilton depression rating scale (HAMD-24), Herth Hope Scale (HHS), Connor-Davidson Resilience Scale (CD-RISC), and Family Adaptability and Cohesion Evaluation Scale, second edition (FACES-II-CV), respectively.ResultA total of 118 participants completed the trial. Both groups showed a significant reduction in NSSI frequency after 12, 24, and 36 weeks of intervention (p< 0.05), although the intervention group did not differ significantly from the control group. After 12, 24, and 36 weeks of intervention, the CD-RISC, HHS, HAMD-24, and FACES-II-CV scores in the intervention and control groups improved over baseline (p< 0.05). Furthermore, the intervention group had higher scores on the CD-RISC, HHS, and FACES-II-CV and lower scores on the HAMD-24 than the control group after 12, 24, and 36 weeks of intervention (p  < 0.05).ConclusionParent–child group emotional regulation and resilience training showed promise as treatment options for NSSI among adolescents, leading to increased hope, resilience, and improved family dynamics among NSSI teens. Moreover, NSSI frequency significantly decreased in the intervention group compared to baseline

Nanoplanktonic diatom rapidly alters sinking velocity via regulating lipid content and composition in response to changing nutrient concentrations

Diatom sinking plays a crucial role in the global carbon cycle, accounting for approximately 40% of marine particulate organic carbon export. While oceanic models typically represent diatoms as microphytoplankton (> 20 μm), it is important to recognize that many diatoms fall into the categories of nanophytoplankton (2-20 μm) and picophytoplankton (< 2 μm). These smaller diatoms have also been found to significantly contribute to carbon export. However, our understanding of their sinking behavior and buoyancy regulation mechanisms remains limited. In this study, we investigate the sinking behavior of a nanoplanktonic diatom, Phaeodactylum tricornutum (P. tricornutum), which exhibits rapid changes in sinking behavior in response to varying nutrient concentrations. Our results demonstrate that a higher sinking rate is observed under phosphate limitation and depletion. Notably, in phosphate depletion, the sinking rate of P. tricornutum was 0.79 ± 0.03 m d-1, nearly three times that of the previously reported sinking rates for Skeletonema costatum, Ditylum brightwellii, and Chaetoceros gracile. Furthermore, during the first 6 h of phosphate spike, the sinking rate of P. tricornutum remained consistently high. After 12 h of phosphate spike, the sinking rate decreased to match that of the phosphate repletion phase, only to increase again over the next 12 hours due to phosphate depletion. This rapid sinking behavior contributes to carbon export and potentially allows diatoms to exploit nutrient-rich patches when encountering increased nutrient concentrations. We also observed a significant positive correlation (P< 0.001) between sinking rate and lipid content (R = 0.91) during the phosphate depletion and spike experiment. It appears that P. tricornutum regulates its sinking rate by increasing intracellular lipid content, particularly digalactosyldiacylglycerol, hexosyl ceramide, monogalactosyldiacylglycerol, and triglycerides. Additionally, P. tricornutum replaces phospholipids with more dense membrane sulfolipids, such as sulfoquinovosyldiacylglycerol under phosphate shortage. These findings shed light on the intricate relationship between nutrient availability, sinking behavior, and lipid composition in diatoms, providing insights into their adaptive strategies for carbon export and nutrient utilization