Novel Method for Estimating Time-Varying COVID-19 Transmission Rate

The transmission rate is an important indicator for characterizing a virus and estimating the risk of its outbreak in a certain area, but it is hard to measure. COVID-19, for instance, has greatly affected the world for more than 3 years since early 2020, but scholars have not yet found an effective method to obtain its timely transmission rate due to the fact that the value of COVID-19 transmission rate is not constant but dynamic, always changing over time and places. Therefore, in order to estimate the timely dynamic transmission rate of COVID-19, we performed the following: first, we utilized a rolling time series to construct a time-varying transmission rate model and, based on the model, managed to obtain the dynamic value of COVID-19 transmission rate in mainland China;second, to verify the result, we used the obtained COVID-19 transmission rate as the explanatory variable to conduct empirical research on the impact of the COVID-19 pandemic on China's stock markets. Eventually, the result revealed that the COVID-19 transmission rate had a significant negative impact on China's stock markets, which, to some extent, confirms the validity of the used measurement method in this paper. Notably, the model constructed in this paper, combined with local conditions, can not only be used to estimate the COVID-19 transmission rate in mainland China but also in other affected countries or regions and would be applicable to calculate the transmission rate of other pathogens, not limited to COVID-19, which coincidently fills the gaps in the research. Furthermore, the research based on this model might play a part in regulating anti-pandemic governmental policies and could also help investors and stakeholders to make decisions in a pandemic setting.

REVISITING TEMPORAL CAUSALITY BETWEEN ISLAMIC FINANCE INSTRUMENTS AND OUTPUT

With the onset of the COVID-19 pandemic, financing would again be the crux of the recovery process. This paper revisits existing literature on how financial development promotes growth by focusing on the role of Islamic finance in Malaysia. Specifically, the role of sukuk and loans by Islamic banks on output is examined in Malaysia. The main objective of this paper is to investigate the causal nexus between sukuk, Islamic banking loan, and output using a bootstrap causality test applied to both full sample and rolling window sub-samples. Data ranges from 2000M1-2021M6 for the sukuk market and 2006M12-2021M6 for Islamic banking loans. We rely on bootstrap rolling windows which allow for time-varying causalities within time-series data. Results indicate evidence that Islamic financing instruments, in this case, sukuk and loans by Islamic banks Granger-cause output in the long run. Even in the long run, non-constancy in the parameters is detected for total sukuk, sukuk for finance, and sukuk for transport. The parameter stability tests indicate parameter non-constancy in the short run for total sukuk, sukuk for finance, sukuk for transport, and sukuk for utility for the output-sukuk equation. In the case of Islamic financing via loans, short-run parameter instability is prevalent for all loan–output equations. We take the analysis further by examining the direction of the lead variables on a multi-time scale using continuous wavelet transforms and wavelet coherence. Results show that causality runs from sukuk output for total sukuk, transport, and utility sukuk whereas construction sukuk seems to exhibit a mixed behaviour. In the case of sukuk for finance, the impact is more pronounced in the very-long run. These findings could be a guide for countries intending to use Islamic financing instruments as one of the tools for fiscal stimulus or post-pandemic economic recovery. © 2023, Universiti Malaysia Sarawak. All rights reserved.

Localized surface plasmon resonance biosensor chip surface modification and signal amplifications toward rapid and sensitive detection of COVID-19 infections.

We developed a multi-pronged approach to enhance the detection sensitivity of localized surface plasmon resonance (LSPR) sensor chips to detect SARS-CoV-2. To this end, poly(amidoamine) dendrimers were immobilized onto the surface of LSPR sensor chips to serve as templates to further conjugate aptamers specific for SARS-CoV-2. The immobilized dendrimers were shown to reduce surface nonspecific adsorptions and increase capturing ligand density on the sensor chips, thereby improving detection sensitivity. To characterize the detection sensitivity of the surface-modified sensor chips, SARS-CoV-2 spike protein receptor-binding domain was detected using LSPR sensor chips with different surface modifications. The results showed that the dendrimer-aptamer modified LSPR sensor chip exhibited a limit of detection (LOD) of 21.9 pM, a sensitivity that was 9 times and 152 times more sensitive than the traditional aptamer- or antibody-based LSPR sensor chips, respectively. In addition, detection sensitivity was further improved by combining rolling circle amplification product and gold nanoparticles to further amplify the detection signals by increasing both the target mass and plasmonic coupling effects. Using pseudo SARS-CoV-2 viral particles as detection targets, we demonstrated that this combined signal intensification approach further enhanced the detection sensitivity by 10 folds with a remarkable LOD of 148 vp/mL, making it one of the most sensitive SARS-CoV-2 detection assays reported to date. These results highlight the potential of a novel LSPR-based detection platform for sensitive and rapid detection of COVID-19 infections, as well as other viral infections and point-of-care applications.

Performance Evaluation of Lithuanian II Pillar Pension Funds Using Rolling Window Technique

This paper presents results of performance evaluation of Lithuanian II pillar pension funds using rolling window technique. The Lithuanian pension system has three pillars: mandatory (Ist, social insurance system), quasi-optional (IInd, life-cycle pension funds) and optional (IIIrd, any kind of pension funds or insurance). Investments in II pillar from standard funds were changed to life-cycle funds in 2019. To reveal different behavior of market risk and performance of funds, we used 120 days windows (rolled by 1 day). Risk-adjusted performance of funds was measured by employing mean return, average recovery and Sharpe-based ratios such Calmar ratio, Sortino ratio, adjusted Sharpe ratio, VaR Sharpe ratio. However, to describe market risk we only focused on 5 special time windows related to COVID-19.

FoMO in the Bitcoin market: Revisiting and factors

We revisit the "fear of missing out” (FoMO) effect of Bitcoin by observing asymmetric volatility dynamics and further investigate its driving factors. Using a longer sample period covering the COVID-19 pandemic, our results show evidence of positive asymmetric volatility behavior in the Bitcoin market, confirming the presence of the FoMO effect. This effect also exists in some other major cryptocurrencies. Further analysis indicates that the happiness index, the ratio of short-term to long-term Bitcoin trading volume, and the geopolitical risk index contribute positively to the FoMO, while the volatility index and the Twitter-based uncertainty index exert an opposite effect.

Can Consumer Credit Stimulate Consumer Confidence? Evidence from the Time-Varying Aspect

This study discusses the nexus between consumer credit (CC) and consumer confidence (CF) in the case of China with a bootstrap rolling-window causality test. The new empirical results demonstrate that CC improves CF in specific periods by loosening liquidity constraints and increasing consumer power temporarily. Meanwhile, a negative link is also found, which can be explained by policy adjustment and financial instabilities. On the contrary, CF negatively influences CC in some periods, reflecting consumers' attitudes toward the future would change borrowing behaviors. But this relationship would be disrupted by government intervention and public events such as the COVID-19 pandemic. The contribution is that time-varying, multiple-directional and dynamic causalities are captured, which enriches the theoretical framework between CC and CF. Therefore, the government must design and adjust loaning policies against specific circumstances and transmit positive signs to consumers. Future study needs to pay attention to different types of CC and try to reveal their heterogeneous influences on CF. In addition, the effect evaluation for CC policy is also another focus in the next research.

Beads- and oil-free single molecule assay with immuno-rolling circle amplification for detection of SARS-CoV-2 from saliva.

Digital enzyme linked immunosorbent assays (ELISA) can be used to detect various antigens such as spike (S) or nucleocapsid (N) proteins of SARS-CoV-2, with much higher sensitivity compared to that achievable using conventional antigen tests. However, the use of microbeads and oil for compartmentalization in these assays limits their user-friendliness and causes loss of assay information due to the loss of beads during the process. To improve the sensitivity of antigen test, here, we developed an oil- and bead-free single molecule counting assay, with rolling circle amplification (RCA) on a substrate. With RCA, the signal is localized at the captured region of an antigen, and the signal from a single antigen molecule can be visualized using the same immune-reaction procedures as in the conventional ELISA. Substrate-based single molecule assay was theoretically evaluated for kd value, and the concentration of capture and detection antibodies. As a feasibility test, biotin-conjugated primer and mouse IgG conjugates were detected even at femto-molar concentrations with this digital immuno-RCA. Using this method, we detected the N protein of SARS-CoV-2 with a limit of detection less than 1 pg/mL more than 100-fold improvement compared to the detection using conventional ELISA. Furthermore, testing of saliva samples from COVID-19 patients and healthy controls (n = 50) indicated the applicability of the proposed method for detection of SARS-CoV-2 with 99.5% specificity and 90.9% sensitivity.

Rothko, the Rolling Stones, and Matisse: Grounding in a time of uncertainty

In surfing the waves of COVID-19 and the current socio-political culture of alarm, uncertainty, and anxiety, I describe how exploring works by Mark Rothko, the Rolling Stones, and Henri Matisse helped me find grounded experiential footing during the pandemic. Rothko's multiform and later paintings encouraged exploration of the soul, experiences of the ineffable, of life-and-death. In contrast, the Rolling Stones inspired me to feel my heart, my beat, my connectedness to rhythm and knowledge that presence rests on interpersonal connection. Finally, as seen in The Red Studio, Matisse and his use of color re-vivify the experience of living, and provided a roadmap back to optimism.

Dynamic causality between oil prices and stock market indexes in Russia and China: does US financial instability matter?

Purpose: This study aims to examine the dynamic bidirectional causality between oil price (OIL) and stock market indexes in net oil-exporting (Russia) and net oil-importing (China) countries. Design/methodology/approach: The authors use monthly data for the period starting from October 1995 to October 2021. In this study, the bootstrap rolling-window Granger causality approach introduced by Balcilar et al. (2010) and the probit regression model are performed in order to identify the bidirectional causality. Findings: The results show that the causal periods mainly occur during economic, financial and health crises. For oil-exporting country, the results suggest that any increase (decrease) in the OIL leads to an appreciation (depreciation) in the stock market index. The effect of the stock market on OIL is more relevant for the oil-importing country than that for the oil-exporting one. The COVID-19 consequences are demonstrated in the impact of oil on the Russian stock market. The probit regression shows that the US financial instabilities increase the probability of causality between OIL and stock market indexes in Russia and China. Practical implications: The dynamic relationship between the variables must be taken into account in investment decisions. As financial instabilities in the USA drive the relationship between oil and stocks, investors should consider geopolitical, economic and financial elements when constructing their portfolios. Shareholders are required to include other assets in their portfolios since oil–stock relationship is highly risky. Originality/value: This study provides further evidence of the bidirectional oil–stock causal link. Additionally, it examines the impact of financial instabilities on the probability that the OIL and the stock market index cause each other through the Granger effect. © 2023, Emerald Publishing Limited.

Detection of SARS-CoV-2 receptor binding domain using fluorescence probe and DNA flowers enabled by rolling circle amplification.

Using rolling circle amplification (RCA) and two different ways of signal readout, we developed analytical methods to detect the receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S protein). We modified streptavidin-coated magnetic beads with an aptamer of RBD through a biotin-tagged complementary DNA strand (biotin-cDNA). Binding of RBD caused the aptamer to dissociate from the biotin-cDNA, making the cDNA available to initiate RCA on the magnetic beads. Detection of RBD was achieved using a dual signal output. For fluorescence signaling, the RCA products were mixed with a dsDNA probe labeled with fluorophore and quencher. Hybridization of the RCA products caused the dsDNA to separate and to emit fluorescence (λex = 488 nm, λem = 520 nm). To generate easily detectable UV-vis absorbance signal, the RCA amplification was extended to produce DNA flower to encapsulate horseradish peroxidase (HRP). The HRP-encapsulated DNA flower catalyzed a colorimetric reaction between H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB) to generate an optical signal (λabs = 450 nm). The fluorescence and colorimetric assays for RBD have low detection limits (0.11 pg mL-1 and 0.904 pg mL-1) and a wide linear range (0.001-100 ng mL-1). For detection of RBD in human saliva, the recovery was 93.0-100% for the fluorescence assay and 87.2-107% for the colorimetric assay. By combining fluorescence and colorimetric detection with RCA, detection of the target RBD in human saliva was achieved with high sensitivity and selectivity.

Rapid whole genome sequencing methods for RNA viruses.

RNA viruses are the etiological agents of many infectious diseases. Since RNA viruses are error-prone during genome replication, rapid, accurate and economical whole RNA viral genome sequence determination is highly demanded. Next-generation sequencing (NGS) techniques perform whole viral genome sequencing due to their high-throughput sequencing capacity. However, the NGS techniques involve a significant burden for sample preparation. Since to generate complete viral genome coverage, genomic nucleic acid enrichment is required by reverse transcription PCR using virus-specific primers or by viral particle concentration. Furthermore, conventional NGS techniques cannot determine the 5' and 3' terminal sequences of the RNA viral genome. Therefore, the terminal sequences are determined one by one using rapid amplification of cDNA ends (RACE). However, since some RNA viruses have segmented genomes, the burden of the determination using RACE is proportional to the number of segments. To date, there is only one study attempting whole genome sequencing of multiple RNA viruses without using above mentioned methods, but the generated sequences' accuracy compared to the reference sequences was up to 97% and did not reach 100% due to the low read depth. Hence, we established novel methods, named PCR-NGS and RCA-NGS, that were optimized for an NGS machine, MinION. These methods do not require nucleic acid amplification with virus-specific PCR primers, physical viral particle enrichment, and RACE. These methods enable whole RNA viral genome sequencing by combining the following techniques: (1) removal of unwanted DNA and RNA other than the RNA viral genome by nuclease treatment; (2) the terminal of viral genome sequence determination by barcoded linkers ligation; (3) amplification of the viral genomic cDNA using ligated linker sequences-specific PCR or an isothermal DNA amplification technique, such as rolling circle amplification (RCA). The established method was evaluated using isolated RNA viruses with single-stranded, double-stranded, positive-stranded, negative-stranded, non-segmented or multi-segmented genomes. As a result, all the viral genome sequences could be determined with 100% accuracy, and these mean read depths were greater than 2,500×, at least using either of the methods. This method should allow for easy and economical determination of accurate RNA viral genomes.

Isothermal Amplification Technology for Disease Diagnosis.

Isothermal amplification (IA) is a nucleic acid amplification technology (NAAT) that has contributed significantly to the healthcare system. The combination of NAAT with a suitable detection platform resulted in higher sensitivity, specificity, and rapid disease diagnosis. Traditional NAAT, such as polymerase chain reaction (PCR), is widely applied in the general healthcare system but is rarely accessed in resource-limited hospitals. Some IA methods provide a rapid, sensitive, specific, and simple method for disease diagnosis. However, not all IA techniques have been regularly used in clinical applications because different biomarkers and sample types affect either the enzyme in the IA system or sample preparation. This review focuses on the application of some IA techniques that have been applied in the medical field and have the potential for use at points of care.

Colonial legacies on employment: comparisons between some former Anglophone and French colonies

Purpose: In this paper, the author assesses if the effect of structural policies, macroeconomic indicators and demographic factors on employment elasticities over the period 2000–2017 can distinguish the former French colonies from the Anglophone ones. Design/methodology/approach: Using a panel of 44 countries taken from Africa and Middle East Area, elasticities are estimated in the first stage by rolling regression. Then, both static and dynamic panel models are investigated. Findings: Results suggest big difference between the former French colonies and Anglophone ones. For the French colonies, product and labor market flexibility are found to have significant and positive impact on elasticities, while for Anglophone ones, only foreign direct investment and government size are found to have significant and positive impact. Besides, all reforms and/or economic measures need to be complemented by macroeconomic policies aimed to increase economic stability. Originality/value: The results presented in this study highlight some of the factors that appear to drive the relationship between employment and some structural policies, macroeconomic indicators and demographic factors for two groups of former colonies. The paper provides policy conclusions based on these results for the two groups. This analysis may indeed help to inform future policy discussions, yet much additional work is needed to identify macroeconomic "best practices” for encouraging employment in the post-2019 covid crisis period. © 2022, Malika Neifar.

Through Running and Integration of Federal Railroad Administration and Federal Transit Administration Regulated Passenger Trains: A Path Toward Mixing Intercity, Commuter, Metro, and Light Rail on the Same Tracks

U.S. rail transit (subways, metros, and light rail) and Federal Railroad Administration (FRA) regulated heavy rail (commu-ter, intercity and regional rail) operate completely separately in revenue service. This necessitates transfers between the modes at terminals. While not unique to the U.S.A., its version of this practice is extreme and prevents the development of robust seamless rail networks. Especially in the post-Covid environment, this leaves commuter rail in search of a mission and rail transit isolated from suburbs. This paper discusses the statutory regulatory scheme that divides the two modes in the U.S.A. It will analyze the justification for the segregation and its history. Such issues include potential collisions, weight, crashworthiness, electrification, signaling, loading gauge, platform height, and operating practices. This paper concludes that the regulatory barrier preventing an FRA-regulated train from going onto a non-FRA railroad are surmountable. Running through trains between the FRA-regulated system and the rail transit network would enhance regional networks. The ‘‘Karlsruhe model'' in Germany and the through running of regional trains onto the Tokyo subway network are two prime examples. Recent technological advances—such as dual mode battery multiple units, robust signaling systems such as Communications Based Train Control and Positive Train Control, and advanced car body designs able to deal with different loading gauges—make through running more practical. With little or no new right-of-way, it is possible to create far more useful rail networks. Potential shared networks at the conceptual level are discussed for Los Angeles, Seattle, Washington, D.C., Dallas, and Sacramento. © National Academy of Sciences: Transportation Research Board 2022.

Detection of Large Genomic RNA via DNAzyme-Mediated RNA Cleavage and Rolling Circle Amplification: SARS-CoV-2 as a Model.

A new method for the detection of genomic RNA combines RNA cleavage by the 10-23 DNAzyme and use of the cleavage fragments as primers to initiate rolling circle amplification (RCA). 230 different 10-23 DNAzyme variants were screened to identify those that target accessible RNA sites within the highly structured RNA transcripts of SARS-CoV-2. A total of 28 DNAzymes were identified with >20 % cleavage, 5 with >40 % cleavage and one with >60 % in 10 min. The cleavage fragments from these reactions were then screened for coupling to an RCA reaction, leading to the identification of several cleavage fragments that could efficiently initiate RCA. Using a newly developed quasi-exponential RCA method with a detection limit of 500 aM of RNA, 14 RT-PCR positive and 15 RT-PCR negative patient saliva samples were evaluated for SARS-CoV-2 genomic RNA, achieving a clinical sensitivity of 86 % and specificity of 100 % for detection of the virus in <2.5 h.

Examining the adaptive market hypothesis with calendar effects: International evidence and the impact of COVID-19

This study examines whether the adaptive market hypothesis (AMH) explains calendar anomalies across 16 headline stock market indices in 10 markets. We employ the rolling window analysis and estimate a T-GARCH (1,1) for a long time series that includes two years coinciding with the COVID-19 pandemic. Overall, the empirical results reveal that calendar day anomalies across our sample markets exhibit time-varying behavior, evolving through patterns that shift markets between periods of efficiency and inefficiency, thereby providing support for the AMH framework. The results also highlight the calendar anomalies that reappeared after the onset of the COVID-19 pandemic across international markets. © 2022 Elsevier Inc.

Time-frequency correlations and extreme spillover effects between carbon markets and NFTs: The roles of EPU and COVID-19

This paper examines the correlations and spillover effects between carbon markets and NFTs, and explores the roles of EPU and COVID-19, utilizing the rolling window wavelet correlation and the quantile frequency connectedness approach. We find, first, strong correlations between returns mainly exist in the long term. Second, the extreme volatility spillover in the carbon-NFT system is greater and faster than in normal case. Third, major international events increase the total connectedness of the system. Fourth, COVID-19 inhibits carbon-NFTs' extreme spillover effect, while China's EPU has positive impacts. Our results also provide valuable references and policy implications for investors and policymakers.

A Rolling-Based Multipeak Learning Model for COVID-19 Pandemic Predicting

The COVID-19 pandemic has led to a dramatic loss of human life and the global economy, and presents an unprecedented challenge to public health management for all countries around the world. Access to an accurate epidemic prediction model plays a crucial role in epidemic prevention, infection scale control, and medical resource allocation. In this paper, we first propose a multipeak SEIYAQURD model by using the multipeak learning algorithm to predict the COVID-19 epidemic. The model separates the total population according to characteristics of COVID-19 and can capture trend changes in the epidemic. Then, the fitting period technique and the rolling prediction strategy are proposed to improve the prediction accuracy. Numerical experiments based on the data of COVID-19 in the United States are performed to demonstrate the effectiveness of our proposed method by comparing with two benchmark methods from the literature in two cases, one has a smooth trend and the other has a significant changing trend. © 2022 IEEE.

Is a consumer loan a catalyst for confidence?

In the context of the global economic downturn, the approach guided by consumer loans (CL) to boost consumer confidence is a feasible way to promote the internal circulation of the Chinese economy. Therefore, we use a time-varying rolling-window approach to identify how CL affects the consumer confidence index (CCI). We find that CL can be seen as vital support for promoting confidence because it can ease liquidity constraints and improve consumption levels. The empirical outcome is supported by the Rational Expectations Perpetual Income Hypothesis (RE-PIH), emphasizing that increasing CL can boost consumer confidence. Conversely, CCI has both positive and negative effects on CL. The positive effects suggest that consumers’ optimistic confidence leads them to increase borrowing, which in turn creates a heavier debt burden. This statement cannot be supported by the negative effect due to consumers’ blind self-confidence will cause cognitive bias, which is not conducive to the loan market development. Against the backdrop of increased global uncertainty due to the COVID-19 pandemic and the government’s continuous adjustment of loan policies, consumers can effectively optimise their consumption decision-making through borrowing. The policymaker can maintain loan stability by effectively promoting consumer confidence and raising the consumption level of the whole society. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Colonial legacies on employment: comparisons between some former Anglophone and French colonies

PurposeIn this paper, the author assesses if the effect of structural policies, macroeconomic indicators and demographic factors on employment elasticities over the period 2000-2017 can distinguish the former French colonies from the Anglophone ones.Design/methodology/approachUsing a panel of 44 countries taken from Africa and Middle East Area, elasticities are estimated in the first stage by rolling regression. Then, both static and dynamic panel models are investigated.FindingsResults suggest big difference between the former French colonies and Anglophone ones. For the French colonies, product and labor market flexibility are found to have significant and positive impact on elasticities, while for Anglophone ones, only foreign direct investment and government size are found to have significant and positive impact. Besides, all reforms and/or economic measures need to be complemented by macroeconomic policies aimed to increase economic stability.Originality/valueThe results presented in this study highlight some of the factors that appear to drive the relationship between employment and some structural policies, macroeconomic indicators and demographic factors for two groups of former colonies. The paper provides policy conclusions based on these results for the two groups. This analysis may indeed help to inform future policy discussions, yet much additional work is needed to identify macroeconomic "best practices" for encouraging employment in the post-2019 covid crisis period.