A two-stage Data Envelopment Analysis Approach Incorporating Global Bounded Adjustment Measure to evaluate the efficiency of medical waste recycling systems with undesirable inputs and outputs (preprint)

With the ever-increasing focus on sustainable development, recycling waste and renewable use of waste products has earned immense consideration from academics and policy-makers. The serious pollution, complex types, and strong infectivity of medical waste (MW) have brought serious challenges to management. Although several researchers have addressed the issue of the MW by optimizing MW management networks and systems, there is still a significant gap in systematically evaluating the efficiency of MW recycling systems. Therefore, this paper proposes a two-stage data envelopment analysis (DEA) approach that combines the virtual frontier and the global bounded adjustment measure (BAM-VF-G), considering both undesirable inputs and outputs. In the first stage, the BAM-G model is used to evaluate the efficiency of MW recycling systems, and the BAM-VF-G model is used to further rank super-efficient MW recycling systems. In the second stage, two types of efficiency decomposition models are proposed. The first type of models decomposes unified efficiency into production efficiency (PE) and environment efficiency (EE). Depending upon the systems structure, the second type of models decomposes unified efficiency into the efficiency of the MW collection and transport subsystem (MWCS) and the efficiency of the MW treatment subsystem (MWTS). The novel approach is used to measure the efficiency of the MW recycling systems in China's new first-tier cities (CNFCs), and we find that: (1) Foshan ranks the highest in efficiency, followed by Qingdao and Dongguan, with efficiency values of 0.3593, 0.1765, and 0.1530, respectively. (2) EE has always been lower than PE and is a critical factor influencing the overall efficiency of MW recycling systems in CNFCs. (3) The MWCS lacks resilience, with an efficiency 0.042 lower than that of the MWTC. Following the outbreak of COVID-19, the efficiency of the MWCS has been decreasing year by year, reaching only 0.762 in 2021, which is a decline of 0.111 compared to 2017.

The Relationship between Exercise Behavior and Mental Health during the COVID-19 Epidemic: Research Based on the Weibo Exercise Behavior User Dictionary

In the context of COVID-19, people face conditions of great stress and are susceptible to negative emotions such as worry, fear, and doubt. Therefore, the focus of epidemic prevention should be on mental health as well as physical health. It is important to pay attention to people's mental health while mitigating and controlling the epidemic. As an intervention to improve mental health, exercise behavior has attracted increasing attention from scholars due to its convenience and low cost. Therefore, the goal of this paper was to investigate the differences between characteristics related to linguistic expression and mental health indicators among different groups of Weibo users by constructing a Weibo exercise behavior user lexicon to explore the influence of exercise behavior on mental health. This study developed a user dictionary of exercise behavior, classified Sina Weibo users' exercise behavior, and established relevant systems to uncover the expressive characteristics of psychological vocabulary and behavioral vocabulary to explore the differences in expressive features related to psychological and behavioral vocabulary and mental health indicators among users who engage in different forms of exercise behavior during the period of COVID-19. As a result of an analysis of variance (ANOVA) conducted during the COVID-19 epidemic, (1) based on the constructed user lexicon of motion behavior in Weibo, the classification program exhibited good performance;(2) there were significant differences in the expressions of some lexical features among users who exhibited different motor behaviors;and (3) both nonphysical exercise and physical exercise behavior had positive relationships with some mental health indicators, but the mechanism associated with nonphysical exercise requires further exploration. This study provides a scientific online evaluation methodology and support for research concerning exercise and mental health during the COVID-19 epidemic.

Weibo Text Sentiment Analysis Based on BERT and Deep Learning

With the rapid increase of public opinion data, the technology of Weibo text sentiment analysis plays a more and more significant role in monitoring network public opinion. Due to the sparseness and high-dimensionality of text data and the complex semantics of natural language, sentiment analysis tasks face tremendous challenges. To solve the above problems, this paper proposes a new model based on BERT and deep learning for Weibo text sentiment analysis. Specifically, first using BERT to represent the text with dynamic word vectors and using the processed sentiment dictionary to enhance the sentiment features of the vectors;then adopting the BiLSTM to extract the contextual features of the text, the processed vector representation is weighted by the attention mechanism. After weighting, using the CNN to extract the important local sentiment features in the text, finally the processed sentiment feature representation is classified. A comparative experiment was conducted on the Weibo text dataset collected during the COVID-19 epidemic;the results showed that the performance of the proposed model was significantly improved compared with other similar models.

Household Secondary Attack Rate of COVID-19 and Associated Determinants (preprint)

Background: As of April 2, 2020, the global reported number of COVID-19 cases has crossed over 1 million with more than 55,000 deaths. The household transmissibility of SARS-CoV-2, the causative pathogen, remains elusive. Methods: Based on a comprehensive contact-tracing dataset from Guangzhou, we estimated both the population-level effective reproductive number and individual-level secondary attack rate (SAR) in the household setting. We assessed age effects on transmissibility and the infectivity of COVID-19 cases during their incubation period. Results: A total of 195 unrelated clusters with 212 primary cases, 137 nonprimary (secondary or tertiary) cases and 1938 uninfected close contacts were traced. We estimated the household SAR to be 13.8% (95% CI: 11.1-17.0%) if household contacts are defined as all close relatives and 19.3% (95% CI: 15.5-23.9%) if household contacts only include those at the same residential address as the cases, assuming a mean incubation period of 4 days and a maximum infectious period of 13 days. The odds of infection among children (<20 years old) was only 0.26 (95% CI: 0.13-0.54) times of that among the elderly ([≥]60 years old). There was no gender difference in the risk of infection. COVID-19 cases were at least as infectious during their incubation period as during their illness. On average, a COVID-19 case infected 0.48 (95% CI: 0.39-0.58) close contacts. Had isolation not been implemented, this number increases to 0.62 (95% CI: 0.51-0.75). The effective reproductive number in Guangzhou dropped from above 1 to below 0.5 in about 1 week. Conclusion: SARS-CoV-2 is more transmissible in households than SARS-CoV and MERS-CoV, and the elderly [≥]60 years old are the most vulnerable to household transmission. Case finding and isolation alone may be inadequate to contain the pandemic and need to be used in conjunction with heightened restriction of human movement as implemented in Guangzhou.

Epidemiological and clinical characteristics of imported cases with COVID-19 infection: a multicentre study (preprint)

Objective: Numerous cases of COVID-19 were confirmed in the world in succession. We reported the epidemiological and clinical features of 478 confirmed cases from a multicentre study outside of Wuhan, China. Methods : We collected patients who were transferred by Emergency Medical Service to the designated hospitals in four major cities including Beijing, Chongqing, Jinan and Nanning in China. We compared the characteristics between imported and indigenous cases, and calculated the fatality, and the rate of severe cases, mild and asymptomatic cases to generate the pyramid of COVID-19 infection. Results : The mean age of patients was 46.9 years old and 49.8% were male. The most common symptoms at the onset of illness were fever (69.7% ), cough (47.5%), fatigue (24.5%), dyspnea (8.4%) and headache (7.9%). In the study, most cases (313, 65.5%) were indigenous, while 165 (34.5%) were imported. During the early stage, the imported cases were dominant, which declined from Feb 1, when the indigenous cases rise sharply. Compared with the indigenous cases, the imported cases were significantly distinct concerning gender composition (P=0.002), classification of severity (P=0.006). Conclusions : On the basis of this study, we suggest that preventing import from outside and controlling spread inside should be a basic principle for resisting COVID-19 infection. If not, the region or area will face chaos.

Modes of contact and risk of transmission in COVID-19 among close contacts (preprint)

Background Rapid spread of SARS-CoV-2 in Wuhan prompted heightened surveillance in Guangzhou and elsewhere in China. Modes of contact and risk of transmission among close contacts have not been well estimated. Methods We included 4950 closes contacts from Guangzhou, and extracted data including modes of contact, laboratory testing, clinical characteristics of confirmed cases and source cases. We used logistic regression analysis to explore the risk factors associated with infection of close contacts. Results Among 4950 closes contacts, the median age was 38.0 years, and males accounted for 50.2% (2484). During quarantine period, 129 cases (2.6%) were diagnosed, with 8 asymptomatic (6.2%), 49 mild (38.0%), and 5 (3.9%) severe to critical cases. The sensitivity of throat swab was 71.32% and 92.19% at first to second PCR test. Among different modes of contact, household contacts were the most dangerous in catching with infection of COVID-19, with an incidence of 10.2%. As the increase of age for close contacts and severity of source cases, the incidence of COVID-19 presented an increasing trend from 1.8% (0-17 years) to 4.2% (60 or over years), and from 0.33% for asymptomatic, 3.3% for mild, to 6.2% for severe and critical source cases, respectively. Manifestation of expectoration in source cases was also highly associated with an increased risk of infection in their close contacts (13.6%). Secondary cases were in general clinically milder and were less likely to have common symptoms than those of source cases. Conclusions In conclusion, the proportion of asymptomatic and mild infections account for almost half of the confirmed cases among close contacts. The household contacts were the main transmission mode, and clinically more severe cases were more likely to pass the infection to their close contacts. Generally, the secondary cases were clinically milder than those of source cases.

Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov (preprint)

A novel coronavirus SARS-CoV-2 was identified in Wuhan, Hubei Province, China in December of 2019. According to WHO report, this new coronavirus has resulted in 76,392 confirmed infections and 2,348 deaths in China by 22 February, 2020, with additional patients being identified in a rapidly growing number internationally. SARS-CoV-2 was reported to share the same receptor, Angiotensin-converting enzyme 2 (ACE2), with SARS-CoV. Here based on the public database and the state-of-the-art single-cell RNA-Seq technique, we analyzed the ACE2 RNA expression profile in the normal human lungs. The result indicates that the ACE2 virus receptor expression is concentrated in a small population of type II alveolar cells (AT2). Surprisingly, we found that this population of ACE2-expressing AT2 also highly expressed many other genes that positively regulating viral entry, reproduction and transmission. This study provides a biological background for the epidemic investigation of the COVID-19, and could be informative for future anti-ACE2 therapeutic strategy development.