Generation of Intense High-Order Vortex Harmonics

This paper presents the method for the first time to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region. In three-dimensional particle-in-cell simulation, both the reflected and transmitted light beams include high-order harmonics of the Laguerre-Gaussian (LG) mode when a linearly polarized LG laser pulse impinges on a solid foil. The mode of the generated LG harmonic scales with its order, in good agreement with our theoretical analysis. The intensity of the generated high-order vortex harmonics is close to the relativistic region, and the pulse duration can be in attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. Thus, the obtained intense vortex beam may have extraordinarily promising applications for high-capacity quantum information and for high-resolution detection in both spatial and temporal scales because of the addition of a new degree of freedom

Urgent need to develop evidence-based self-help interventions for mental health of healthcare workers in COVID-19 pandemic

Thepandemicof COVID-19 has rapidly spread to over 200 countries and territoriesin the past 4months. To save lives and minimizetransmission, millions of healthcareworkers are working in frontlines worldwidebut putting themselves at high risk from the disease. All of themare workingunder extreme pressuresandexperiencinggreat psychological distressin such a challenging situation.In addition to the huge psychological pressure, healthcare workers around the world face morale and burnout issues as they have to make impossible decisions(Greenberg, Docherty, Gnanapragasam, & Wessely, 2020).It is encouraging is that the World Health Organization (WHO) and manyinstitutions have proposedguidelinesto providepsychological assistance for healthcare workers duringthispandemi

Fintech applications on banking stability using big data of an emerging economy.

The rapid growth and development of financial technological advancement (Fintech) services and innovations have attracted the attention of scholars who are now on a quest to analyse their impact on the banking sector. This study conducts several kinds of analyses to measure the effect of the fintech era on the stability of the Chinese banking sector. It uses Big Data and performs Pearson correlation and regression analysis on the fintech era's transition period to measure the impact of several explanatory variables— institutional regulation, government stability, bank credit to deposit ratio, and economic growth— on the outcome variables, which includes Nonperforming loans (NPLs) and its numerical measurement in relation to the mean score of the Big Data (Z-score). This study uses yearly Big Data from 1995-2018 and revealed that compared to the first wave of the fintech era, the second wave helped in the reduction of NPLs and the enhancement of financial stability in China. This study concludes that in the second wave of the fintech era, the explanatory variables mentioned above had a positive impact on NPLs and banking stability. This work helps comprehend fintech development in modern society and the importance of its disruptive forces in developing and developed countries

Generation of Ultra-intense Gamma-ray Train by QED Harmonics

When laser intensity exceeds 10^22W/cm^2, photons with energy above MeV can be generated from high-order harmonics process in the laser-plasma interaction. We find that under such laser intensity, QED effect plays a dominating role in the radiation pattern. Contrast to the gas and relativistic HHG processes, both the occurrence and energy of gamma-ray emission produced by QED harmonics are random and QED harmonics are usually not coherent, while the property of high intensity and ultra-short duration is conserved. Our simulation shows that the period of gamma-ray train is half of the laser period and the peak intensity is 1.4e22W/cm^2. This new harmonic production with QED effects are crucial to light-matter interaction in strong field and can be verified in experiments by 10PW laser facilities in the near future.Comment: 12 pages, 4 figure

Proton Acceleration in Underdense Plasma by Ultraintense Laguerre-Gaussian Laser Pulse

Three-dimensional particle-in-cell simulation is used to investigate the witness proton acceleration in underdense plasma with a short intense Laguerre-Gaussian (LG) laser pulse. Driven by the LG10 laser pulse, a special bubble with an electron pillar on the axis is formed, in which protons can be well-confined by the generated transversal focusing field and accelerated by the longitudinal wakefield. The risk of scattering prior to acceleration with a Gaussian laser pulse in underdense plasma is avoided, and protons are accelerated stably to much higher energy. In simulation, a proton beam has been accelerated to 7 GeV from 1 GeV in underdense tritium plasma driven by a 2.14x1022 W/cm2 LG10 laser pulse

Feed types driven differentiation of microbial community and functionality in marine integrated multitrophic aquaculture system

Integrated multi trophic aquaculture (IMTA) improves the production of aquatic animals by promoting nutrient utilization through different tropical levels. Microorganisms play an important role in elements cycling, energy flow and farmed-species health. The aim of this study was to evaluate how feed types, fresh frozen fish diet (FFD) or formulated diet (FD), influence the microbial community diversity and functionality in both water and sediment in a marine IMTA system. Preferable water quality, higher animal yields and higher cost efficiency were achieved in the FD pond. Feed types changed the pond bacterial community distribution, especially in the rearing water. The FFD pond was dominated with Cyanobacteria in the water, which played an important role in nitrogen fixation through photosynthesis due to the high nitrogen input of the frozen fish diet. The high carbohydrate composition in the formulated diet triggered higher metabolic pathways related to carbon and lipid metabolism in the water of the FD pond. Sediment had significantly higher microbial diversity than the rearing water. In sediment, the dominating genus, Sulfurovum and Desulfobulbus, were found to be positively correlated by network analysis, which had similar functionality in sulfur transformation. The relatively higher rates of antibiotic biosynthesis in the FFD sediment might be related to the pathogenic bacteria introduced by the trash fish diet. The difference in microbial community composition and metabolic pathways may be associated with the different pathways for nutrient cycling and animal growth performance. The formulated diet was determined to be more ecologically and economically sustainable than the frozen fish diet for marine IMTA pond systems.</p

Making therapies culturally relevant: translation, cultural adaptation and field-testing of the Thinking Healthy Programme for perinatal depression in China

BACKGROUND:The prevalence of perinatal depression in China ranges from 15 to 20% and the vast majority of prenatally depressed women do not receive the intervention they require. Recent research evidence shows that evidence based, culturally-adapted psychosocial interventions are effective in reducing mental health problems. The World Health Organization (WHO) has endorsed the Thinking Healthy Programme (THP), which is an evidence based psychosocial intervention that can be delivered by non-mental health specialists. The aim of this study was to translate and adapt THP for the Chinese population and to establish its acceptability when delivered by non-specialists to a group of mothers with perinatal depression. METHODS:The study was conducted in two phases. The THP manual, handbook, and health calendar was translated and adapted based on 8 domains of the Bernal framework (language, metaphors, content, concepts, goals, context, people and methods). Pre-testing was done using cognitive interviewing in the first phase. In second phase of field-testing, THP sessions were delivered to the depressed women by local THP trained nurses. Post intervention, programme survey was used for evaluation. RESULTS:This study showed that the core structure, process and techniques of the THP were culturally compatible with the target Chinese population and did not require major changes. It was found that the adapted version of THP manual, handbook, and health calendar were acceptable, understandable, and culturally relevant to the Chinese women and their family members. Nurses were found as a suitable delivery agent by the mothers and their families. CONCLUSION:The Thinking Healthy Programme is acceptable and transferable to the Chinese cultural and healthcare context and nurses are a suitable delivery agent. The translated and adapted version of THP can be used for further implementation and evaluation studies in the Chinese context. Further evaluation can help establish the effectiveness of the programme and barriers to scale-up in China

Ultra-bright, ultra-broadband hard x-ray driven by laser-produced energetic electron beams

We propose a new method of obtaining a compact ultra-bright, ultra-broadband hard X-ray source. This X-ray source has a high peak brightness in the order of 1022 photons/(s mm2 mrad2 0.1\%BW), an ultrashort duration (10 fs), and a broadband spectrum (flat distribution from 0.1 MeV to 4 MeV), and thus has wide-ranging potential applications, such as in ultrafast Laue diffraction experiments. In our scheme, laser-plasma accelerators (LPAs) provide driven electron beams. A foil target is placed oblique to the beam direction so that the target normal sheath field (TNSF) is used to provide a bending force. Using this TNSF-kick scheme, we can fully utilize the advantages of current LPAs, including their high charge, high energy, and low emittance