RESUMO
Objective: The Omicron variant of SARS-COV-2 is replacing previously circulating variants around the world in 2022. Sporadic outbreaks of the Omicron variant into China have posed a concern how to properly response to battle against evolving coronavirus disease 2019 (COVID-19). Methods: Based on the epidemic data from website announced by Beijing Center for Disease Control and Prevention for the recent outbreak in Beijing from April 22nd to June 8th in 2022, we developed a modified SEPIR model to mathematically simulate the customized dynamic COVID-zero strategy and project transmissions of the Omicron epidemic. To demonstrate the effectiveness of dynamic-changing policies deployment during this outbreak control, we modified the transmission rate into four parts according to policy-changing dates as April 22nd to May 2nd, May 3rd to 11st, May 12th to 21st, May 22nd to June 8th, and we adopted Markov chain Monte Carlo (MCMC) to estimate different transmission rate. Then we altered the timing and scaling of these measures used to understand the effectiveness of these policies on the Omicron variant. Results: The estimated effective reproduction number of four parts were 1.75 (95% CI 1.66-1.85), 0.89 (95% CI 0.79-0.99), 1.15 (95% CI 1.05-1.26) and 0.53 (95% CI 0.48 -0.60), respectively. In the experiment, we found that till June 8th the cumulative cases would rise to 132,609 (95% CI 59,667-250,639), 73.39 times of observed cumulative cases number 1,807 if no policy were implemented on May 3rd, and would be 3,235 (95% CI 1,909 - 4,954), increased by 79.03% if no policy were implemented on May 22nd. A 3-day delay of the implementation of policies would led to increase of cumulative cases by 58.28% and a 7-day delay would led to increase of cumulative cases by 187.00%. On the other hand, taking control measures 3 or 7 days in advance would result in merely 38.63% or 68.62% reduction of real cumulative cases. And if lockdown implemented 3 days before May 3rd, the cumulative cases would be 289 (95% CI 211-378), reduced by 84%, and the cumulative cases would be 853 (95% CI 578-1,183), reduced by 52.79% if lockdown implemented 3 days after May 3rd. Conclusion: The dynamic COVID-zero strategy might be able to effectively minimize the scale of the transmission, shorten the epidemic period and reduce the total number of infections.
RESUMO
A high voltage with a very short duration and fast rising time is beneficial to generate uniform and diffuse plasma in dielectric barrier discharge (DBD) loads, and a power supply with a high power factor (PF) can reduce the impact on the power grid. According to two requirements, a unipolar high voltage pulsed power supply with power factor correction (PFC) is proposed in this paper. The power supply consists of a unipolar pulse high voltage generating unit, a PFC unit, and a driving circuit. By introducing a feedback clamping diode and a reverse current blocking diode in a flyback converter, repetitive nanosecond pulses are generated in the unipolar pulse high voltage generating unit. Because a discontinuous current mode strategy is adopted in the PFC unit and the driving signal is shared by the two units, a compact structure of the power supply is achieved, and a high PF is obtained. To validate the proposed pulsed power supply, an experimental setup is built for a DBD excimer lamp. The results show that the proposed power supply has the capability of not only providing a unipolar nanosecond pulse high voltage for the DBD excimer lamp but also achieving PF close to 1 and total harmonic distortion of less than 24%.
RESUMO
Most of the existing studies on maker-space focus on internal subjects (such as makers) or external factors (such as policy support, ecological environment, and more). There has been relatively little discussion on the design of a series of mechanisms of maker-space. This paper theorizes the operating mechanism for platform services, resource gathering, network connections and endogenous cultural protection for the maker-space. It uses the method of fuzzy set qualitative comparative analysis (fsQCA) to analyze data from 63 maker-spaces in Zhejiang Province. The study proposes a reasonable mechanism design scheme for maker-space. The results show that the innovativeness of a maker-space is the result of the synergistic effect of various operating mechanisms. Among them, the platform service function, the channel for gathering resources, the formal linkages, and the culture for sharing achievements are indispensable support mechanisms for maker-spaces. Two effective ways to promote innovation in maker-space are outlined: first, preventing interventions from external resource providers; second, building an inclusive culture of trial and error.
Assuntos
Meio Ambiente , Serviços de Saúde , HumanosRESUMO
An inflow of foreign capital into the host country would raise her aggregate capital stock, gross savings and investment, economic growth, and environmental quality. This study scrutinizes the asymmetric impact of FDI and remittances to CO2 emissions in China using annual data from 1981 to 2019, via an asymmetric ARDL approach. The findings show that a positive and negative shock in FDI causes a decrease in CO2 emissions in long run. The findings inferred that a negative shock of remittances has a negative impact on the environment by reducing CO2 emissions in long run. While the impact of a negative shock of remittance is more than the impact of a negative shock of FDI on CO2 emissions in long run in China. Thus, government that policymakers should consider foreign capital as a policy instrument especially designing strategies and policies related to environmental sustainability in China.
