ABSTRACT
Question answering over knowledge bases (KBQA) has become a popular approach to help users extract information from knowledge bases. Although several systems exist, choosing one suitable for a particular application scenario is difficult. In this article, we provide a comparative study of six representative KBQA systems on eight benchmark datasets. In that, we study various question types, properties, languages, and domains to provide insights on where existing systems struggle. On top of that, we propose an advanced mapping algorithm to aid existing models in achieving superior results. Moreover, we also develop a multilingual corpus COVID-KGQA, which encourages COVID-19 research and multilingualism for the diversity of future AI. Finally, we discuss the key findings and their implications as well as performance guidelines and some future improvements. Our source code is available at \url{https://github.com/tamlhp/kbqa}.
Subject(s)
COVID-19ABSTRACT
We investigated the impact of environmental transformational leadership (ETL) on pro-environmental behavior (PEB) of employees in Kazakhstan. The study also examined the potential mediating effect of environmental awareness and green human resource management (GHRM) as a moderating effect, using the theory of planned behavior. An online cross-sectional survey was conducted with 268 Kazakh employees from private and public organizations. Structural equation modeling was used to test the theory-driven model. The results show that environmental leadership predicted employees’ PEB, environmental awareness mediated the relationship, and GHRM partially moderated the relationship. The results of bootstrapping tests reveal that environmental awareness played successive mediating roles in the link between ETL and PEBs, but the simple slope test did not support the moderating effect of GHRM. Environmental awareness and GHRM were identified as fundamental mechanisms that accounted for the connection between ETL and PEBs.
ABSTRACT
Background: As of February 21, 2021, 86,992 cases of coronavirus disease 2019 (COVID-19) were confirmed in the Republic of Korea, with 1,557 deaths and 85,435 cases discharged from isolation. This study investigated the infectivity of individuals with COVID-19 who were retested and found to be severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-positive after recovering from their primary illness.Methods: We investigated 295 individuals with recurrent SARS-CoV-2 positive results, and 836 of their close contacts. We attempted virus isolation in 108 individuals with recurrent SARS-CoV-2 positivity using cell culture and confirmed the presence of neutralizing antibodies by means of serological tests.Findings: The average age was 45·2 years (range, 1–95 years) and 64% were female. At the time of retesting, 55·6% were asymptomatic, and symptoms included cough (18·0%), expectoration (11·2%), sore throat (10·8%), and fever (9·2%). The reasons for retesting were screening (46%), persistent symptoms (37·6%), and new contact with a confirmed COVID-19 case (9·5%). Virus isolation was attempted in 108 individuals with recurrent SARS-CoV-2 positivity, and all tested negative. Three new cases were identified among household contacts based on SARS-CoV-2 polymerase chain reaction testing. Two of the three new cases had had contact with the index patient during their primary illness, and all three had antibody evidence of past infection.Interpretation: There was no laboratory evidence of viral shedding and no epidemiological evidence of transmission among individuals with recurrent positivity.Funding Statement: This study was funded by the Korea Disease Control and Prevention Agency (No. 4800-4837-301).Declaration of Interests: The authors declare no conflicts of interest related to the study.Ethics Approval Statement: The study was approved by the KDCA Institutional Review Board (2020-03-01-P-A). The board waived the requirement for written informed consent.
Subject(s)
COVID-19 , Coronavirus Infections , FeverABSTRACT
Background: A real-time reverse transcription polymerase chain reaction (RT-PCR) assay for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was developed to rapidly diagnose coronavirus disease 2019 (COVID-19). Early diagnosis of COVID-19 enables timely treatment and the implementation of public health measures. We validated the sensitivity, specificity, precision, linearity, accuracy, and robustness of a real-time RT-PCR-based assay for SARS-CoV-2 detection and compared the sensitivity and specificity of Emergency Use Authorization (EUA)-approved reagents for COVID-19 with those of the real-time RT-PCR method.Methods: The real-time RT-PCR-based assay was performed to specifically amplify genomic markers of SARS-CoV-2.Results: The real-time RT-PCR assay was highly specific for SARS-CoV-2, and did not amplify genomic fragments of 13 other viruses that cause respiratory diseases. The assay showed high linearity when conducted with a viral isolate from a patient with COVID-19 together with plasmids containing the target genes. The assay showed good repeatability and reproducibility, with a coefficient of variation of 3%, and detected SARS-CoV-2 with a limit of detection of 1 PFU/mL.Conclusions: The present real-time RT-PCR-based assay can diagnose COVID-19 with high accuracy and sensitivity. This approach is highly effective and can facilitate the early diagnosis of COVID-19 without the use of EUA reagents in the Republic of Korea.