Full-orbit studies of wave-particle interaction on the Mega Ampere Spherical Tokamak

Energetic particles with super-Alfv\'enic speeds could potentially drive Alfv\'enic instabilities in a magnetically confined plasma. The driven waves can influence the fast particle distribution function as energetic particles are redistributed or lost to the vessel wall leading to a reduction in energetic particle confinement and heating efficiency. This thesis investigates the interaction between particles and waves via full orbit numerical simulations. The work presented herein takes steps towards the development of a capability to assess whether future reactor scenarios will be susceptible to these adverse effects or not. A full orbit particle tracking code has been developed to calculate particle trajectories and more importantly to compute particle orbital frequencies as they are followed in the simulation. Based on the wave-particle resonance condition, resonant particles are identified using this code for realistic tokamak geometries. Experimental observations of fast-ion driven waves on the MAST tokamak are presented. Magnetic perturbations in the kilo-Hertz range are detected by a set of high resolution Mirnov coils during the neutral beam injection heating phase where the mode frequency is observed to chirp downwards over the course of a magneto-hydrodynamics (MHD) burst. A decrease in fast-ion deuterium alpha signals is found to be correlated with the electromagnetic bursts indicating fast ion redistribution during the MHD activity. Simulation results suggest that the increase in plasma pressure is disproportional to the increase in NBI heating power in the presence of MHD modes. The effect of instabilities on energetic particle behaviour has been analysed by calculating resonance maps and resonant particle orbits. Full orbit calculations show that the chirping frequency broadens the wave-particle resonance region which can result in enhanced particle transport. Preliminary attempts have been made to evaluate fast particle transport induced by chirping modes using the non-linear full orbit \texttt{HALO} code. The chirping behaviour of the mode frequency is simulated by an ad-hoc function similar to experimental measurement. Calculations are performed for a simple cylindrical tokamak geometry and a mocked-up alpha particle distribution. An $n=6$ toroidal Alfv\'en eigenmode (TAE) is found numerically for this equilibrium. The results of the simulations show that fast particles are transported outwards from the plasma centre when chirping modes are present while no significant particle transport is seen when the mode frequency is constant. The level of transport is affected by either mode amplitude or chirping rate. These results suggest that the inclusion of a chirping effect is necessary to study particle redistribution in the presence of fast-ion modes when considering plasma scenarios in the future

DigGAN: Discriminator gradIent Gap Regularization for GAN Training with Limited Data

Generative adversarial nets (GANs) have been remarkably successful at learning to sample from distributions specified by a given dataset, particularly if the given dataset is reasonably large compared to its dimensionality. However, given limited data, classical GANs have struggled, and strategies like output-regularization, data-augmentation, use of pre-trained models and pruning have been shown to lead to improvements. Notably, the applicability of these strategies is 1) often constrained to particular settings, e.g., availability of a pretrained GAN; or 2) increases training time, e.g., when using pruning. In contrast, we propose a Discriminator gradIent Gap regularized GAN (DigGAN) formulation which can be added to any existing GAN. DigGAN augments existing GANs by encouraging to narrow the gap between the norm of the gradient of a discriminator's prediction w.r.t.\ real images and w.r.t.\ the generated samples. We observe this formulation to avoid bad attractors within the GAN loss landscape, and we find DigGAN to significantly improve the results of GAN training when limited data is available. Code is available at \url{https://github.com/AilsaF/DigGAN}.Comment: Accepted to NeurIPS 202

Towards Overcoming the Undercutting Problem

For Bitcoin and similar cryptocurrencies, their mining processes are currently incentivized with fixed block rewards and voluntary transaction fees. However, the block rewards are supposed to vanish gradually and the remaining incentive of transaction fees is optional and arbitrary. Under those circumstances, Carlsten et al.[CCS~2016] find that an interesting undercutting attack, where the attacker deliberately forks an existing chain by leaving wealthy transactions unclaimed to attract petty complaint miners to its fork, can become the equilibrium strategy for miners. Motivated by similar phenomenons in economics, we take a closer look at the undercutting analysis and find the result to be questionable: In [CCS~2016], fees are accumulated at a fixed rate and miners can collect all unclaimed fees regardless of block size limit, which is often not feasible in practice. Besides, ignoring a potentially large amount of fees unclaimable in a single block can inaccurately inflate the profitability of undercutting. In this work, we define a model that considers claimable fees based on available transactions that can be assembled into the block size limit and upgrades petty compliant miners to be rational where they decide whether to move to other chains subject to expected returns from different choices. In this new model, we first identify the conditions that are necessary to make undercutting profitable. Second, we propose a defense against undercutting by manipulating transactions selected into the new block to invalidate the above-identified conditions. Finally, we complement the above analytical results with an experimental analysis over Bitcoin and Monero. We demonstrate that our conditions for undercutting to be profitable are effective (an increase of 0.5-4.5% in Bitcoin and 8% in Monero) and the avoidance technique fulfills its purpose of allowing miners to earn around fair shares.Comment: 15 pages, 6 figure

LncRNA MALAT1: A potential therapeutic target in DSSinduced ulcerative colitis progression in vitro

Purpose: Ulcerative colitis is a severe disease affecting human health worldwide. Studies have shown that lncRNA MALAT1 has a significant correlation with breast, pancreatic, colon and liver cancers, but its effects on colitis is yet to be discovered. In this study, the potential role of lncRNA MALAT1 and the underlying molecular mechanism in DSS-induced colitis were investigated in vitro.Methods: Colorectal mucosal cell line FHC was induced with dextran sulphate sodium (DSS) to form an in vitro colitis model. Transfection procedure was employed to up- or down-regulate the expressions of lncRNA MALAT1 or miR-30c-5p in FHC cells. Cell viabilities were detected by CCK-8 assay. RT-qPCR was applied for evaluating gene expressions in normal FHC and DSS-induced FHC cell lines, while protein expression levels of target genes were examined by Western blot analysis. Starbase was used to predict the molecular interaction between MALAT1 and miR-30c-5p, while luciferase reporter assay was utilized to verify the binding sites between the two genes.Results: Expression of MALAT1 in the DSS-induced FHC cells was high with low cell viabilities, compared to the normal FHC cells. In the DSS-induced colitis-like FHC cells, overexpression of MALAT1 inhibited cell viabilities, while its downregulation promoted it. MiR-30c-5p directly targets MALAT1 and inhibited its expression in DSS-treated FHC cells. Upregulation of miR-30c-5p increased cell viabilities. Bcl-xL expression was inhibited by the up-regulation of MALAT1, while that of Bax was enhanced and the mimics of miR-30c-5p reversed these observations, suggesting that the enhancement of apoptosis promoted by oe-MALAT1 could be inhibited by miR-30c-5p. The interaction between MALAT1 and miR-30c-5p regulated NF-κB/TGF-β/Wnt-β-catenin signaling pathway.Conclusion: Overexpression of MALAT1 led to inhibition of cell viability, while apoptosis and inflammation were promoted by targeting miR-30c-5p via NF-κB/TGF-β/Wnt-β-catenin signaling pathway. These findings suggest MALAT1 as a therapeutic target for treating colitis. Keywords: Colitis, MALAT1, miR-30c-5p, NF-κB/TGF-β/Wnt-β-catenin&nbsp

Pretreatment with antiplatelet drugs improves the cardiac function after myocardial infarction without reperfusion in a mouse model

Background: Reperfusion therapy is known to improve prognosis and limit myocardial damage aftermyocardial infarction (MI). The administration of antiplatelet drugs prior to percutaneous coronaryintervention also proves beneficial to patients with acute MI (AMI). However, a good number of AMIpatients do not receive reperfusion therapy, and it is not clear if they would benefit from antiplateletpre-treatment.Methods: Experimental C57BL/6 mice were randomly allocated to five groups: the sham group,control, post-treatment, pre-treatment, and pre- and post-treatment groups. Acetylsalicylic acid (15 mg/kg), clopidogrel (11 mg/kg), ticagrelor (27 mg/kg), and prasugrel (1.5 mg/kg) were intragastrically administered in the treatment groups. On day 7 post MI, cardiac function and cardiac fibrosis were evaluated using echocardiography and Masson’s trichrome staining, respectively. Histopathological examinations were performed on tissue sections to grade inflammatory cell infiltration. Platelet inhibition was monitored by measuring thrombin-induced platelet aggregation.Results: Left ventricular ejection fraction and fractional shortening improved significantly (p < 0.01)in the pre-treatment groups when compared to the post-treatment and control groups. A significant(p < 0.01) decrease in cardiac fibrosis was observed in the pre-treatment group, compared with the posttreatment and control groups. Inflammatory cell infiltration significantly decreased in the pre-treatment group compared with the control group (p < 0.05). Thrombin-induced platelet aggregation was significantly inhibited by antiplatelet drugs, but increased with the exposure to H2O2.Conclusions: In the absence of reperfusion therapy, pre-treatment with antiplatelet drugs successfullyimproved cardiac function, reduced cardiac fibrosis and inflammatory cell infiltration, and inhibited oxidative stress-induced platelet aggregation after MI in the mouse model

Random coefficient modeling research on short-term forecast of passenger flow into an urban rail transit station

Taking a representative metro station in Beijing as example, this research has newly developed a random coefficient model to predict the short-term passenger flows with sudden increases sometimes into an urban rail transit station. The hierarchical Bayesian approach is iteratively applied in this work to estimate the new model and the estimation outcomes in each of the iterative calibrations are improved by sequential Bayesian updating. It has been proved that the estimation procedure is able to effectively converge to rational results with satisfying accuracies. In addition, the model application study reveals that besides sufficient preparations in manpower, devices, etc.; the information of the factors affecting the passenger flows into an urban rail transit station should be timely transferred in advance from important buildings, road intersections, squares and so on in neighborhood to this station. In this way, this station is able to cope with the unexpectedly sharp increases of the passenger flows into the station to ensure its operation safety

Efficacy and safety of Qixue Tongzhi Granule in improving the exercise capacity of stable coronary artery disease: study protocol for a multicenter, randomized, double-blind, placebo-controlled trial

BackgroundDespite optimal medical therapy, patients with stable coronary artery disease (SCAD) still have a high risk of recurrent cardiovascular events. Exercise capacity measured by cardiopulmonary exercise testing (CPET) is a good surrogate marker for the long-term prognosis of SCAD. Qixue Tongzhi Granule (QTG) is created by academician Chen Keji and has the function of tonifying qi, promoting blood circulation, and regulating qi-flowing. This trial aims to investigate the efficacy and safety of QTG in improving exercise tolerance, alleviating angina pectoris and anxiety/depression symptoms, promoting health-related quality of life, and reducing the risk of adverse cardiovascular events in subjects with SCAD.MethodsThis is a randomized, double-blind, placebo-controlled trial. 150 SCAD patients with qi deficiency, blood stasis, and liver qi stagnation syndrome are enrolled. Patients will be randomly allocated to the QTG or placebo groups at a 1:1 ratio. QTG and placebo will be added to the modern guideline-directed medical therapy for 12 weeks and patients will be followed up for another 24 weeks. The primary outcome is the improvement of metabolic equivalents measured by CPET. The secondary outcomes are cumulative incidence of composite endpoint events, other indicators in CPET, changes in the Seattle Angina Questionnaire, traditional Chinese medicine syndrome scale, 12 items of Short Form Health Survey Questionnaire, Patient Health Questionnaire-9, and Generalized Anxiety Disorder-7, changes of ST-T segment in the electrocardiogram, improvement of left ventricular ejection fraction and left ventricular end-diastolic diameter in echocardiography. In addition, metabolomics analysis will be performed based on blood samples. Adverse events and safety evaluations will also be documented. A full analysis set, per protocol set, and safety analysis set will be conducted.DiscussionThis clinical trial can enrich treatment options for CHD patients with low cardiorespiratory fitness and psychological imbalance, and it may also create a new situation for promoting the application of traditional Chinese medicine in cardiac rehabilitation.Clinical Trial Registration: [http://www.chictr.org.cn], identifier: [ChiCTR2200058988]

TiEV: The Tongji Intelligent Electric Vehicle in the Intelligent Vehicle Future Challenge of China

TiEV is an autonomous driving platform implemented by Tongji University of China. The vehicle is drive-by-wire and is fully powered by electricity. We devised the software system of TiEV from scratch, which is capable of driving the vehicle autonomously in urban paths as well as on fast express roads. We describe our whole system, especially novel modules of probabilistic perception fusion, incremental mapping, the 1st and the 2nd planning and the overall safety concern. TiEV finished 2016 and 2017 Intelligent Vehicle Future Challenge of China held at Changshu. We show our experiences on the development of autonomous vehicles and future trends

Effects of acute administration of different doses of methylphenidate on cognition in healthy young

Os chamados ampliadores cognitivos têm sido ampla e crescentemente utilizados por indivíduos saudáveis, que apesar de não apresentarem nenhum tipo de patologia, buscam por melhoras no desempenho cognitivo. Um fármaco utilizado para este fim é o metilfenidato, droga de primeira escolha para tratamento do transtorno de déficit de atenção e hiperatividade (TDAH). O presente estudo visou verificar o efeito da administração aguda de diferentes doses de metilfenidato (10, 20 e 40 mg e placebo) sobre uma ampla gama de funções cognitivas em jovens saudáveis. Participaram do estudo 36 jovens universitários ou graduados, tendo sido realizados testes de atenção, memória operacional, episódica e semântica. Não foram observadas diferenças no desempenho dos sujeitos em nenhum dos testes. Houve efeito na auto-avaliação de bem estar, sendo este efeito dose dependente – 40 mg > placebo. De acordo com a literatura recente, medicações psicoestimulantes, como o metilfenidato, produzem melhoras no desempenho quando os processos cognitivos estão abaixo de um nível ótimo o que não era o caso dos sujeitos do presente estudo. Sendo assim, a impressão que o metilfenidato melhora o desempenho cognitivo em pessoas jovens e saudáveis se deve provavelmente ao efeito subjetivo de bem estar.The so called cognitive enhancers have been widely and increasingly used by healthy individuals, who despite not having any kind of pathology, seek improvements in cognitive performance. A drug used for this purpose is methylphenidate, a first choice drug for the treatment of the attention deficit and hyperactivity disorder (ADHD). This study aimed to evaluate the effect of acute administration of different doses of methylphenidate (10, 20 and 40 mg and placebo) in a wide range of cognitive functions in healthy young subjects. Participated in the study 36 university students or graduates, and were applied tests of attention, working memory, episodic and semantic memory. There were no differences among the groups in any of the tests. Significant effect on self-assessment of well being was observed, and this effect was dose dependent - 40 mg> placebo. According to recent literature, psychostimulant medications such as methylphenidate, produce improvements in performance when cognitive processes are below an optimal level which was not the case of the subjects of this study. Thus, the impression that methylphenidate improves cognitive performance in healthy young people is probably due to the effect of subjective well-being.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Associação Fundo de Incentivo à Psicofarmacologia (AFIP)BV UNIFESP: Teses e dissertaçõe

Chinese radioglaciological studies on the Antarctic ice sheet: progress and prospects

Chinese radioglaciological studies on the Antarctic ice sheet (AIS) began in 2004/05 when the 21st Chinese National Antarctic Research Expedition (CHINARE 21) team arrived at Dome A for the first time and radio echo sounding (RES) was conducted along the inland traverse and in the Dome A region. Subsequently, more field surveys were conducted along the traverse and in the Dome A region using different radar systems targeting different scientific purposes, such as revealing the landscape of the Gamburtsev Subglacial Mountains by detailed grid RES, or locating a deep ice core drilling site by mapping and studying internal structures, bedrock topography and subglacial conditions in the Dome A region. Furthermore, the evolution of the AIS was inferred from the typical mountain glaciation topography beneath Dome A, and the age of the deep ice core at Kunlun Station was estimated through numerical modeling. Recently, the Snow Eagle 601 airplane was acquired and an airborne geophysical system was constructed to survey the AIS in Princess Elizabeth Land during CHINARE 32 (2015/16) and CHINARE 33 (2016/17) in order to fill the large data gap there. In this paper, we review both the recent progress of Chinese radioglaciological science in Antarctica and future proposed work