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Rigorous Coupled Wave Analysis (RCWA) method is highly efficient for the simulation of diffraction efficiency and field distribution patterns in periodic structures and textured optoelectronic devices. GPU has been increasingly used in complex scientific problems such as climate simulation and the latest Covid-19 spread model. In this paper, we break down the RCWA simulation problem to key computational steps (eigensystem solution, matrix inversion/multiplication) and investigate speed performance provided by optimized linear algebra GPU libraries in comparison to multithreaded Intel MKL CPU library running on IRIDIS 5 supercomputer (1 NVIDIA v100 GPU and 40 Intel Xeon Gold 6138 cores CPU). Our work shows that GPU outperforms CPU significantly for all required steps. Eigensystem solution becomes 60% faster, Matrix inversion improves with size achieving 8x faster for large matrixes. Most significantly, matrix multiplication becomes 40x faster for small and 5x faster for large matrix sizes. © 2023 SPIE.
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BACKGROUND/AIMS: In this study, we aimed to make detailed neurocognitive assessments of patients who presented with brain fog after coronavirus disease-2019 (COVID-19) infection and to investigate their complaints after one-year of follow-up. MATERIALS AND METHODS: Patients who had COVID-19, which was not severe enough to require intensive care, and who subsequently applied to neurology due to cognitive complaints were included in this study. A neurocognitive test battery was applied to those patients who agreed to detailed examination (n=16). This battery consisted of the following tests: mini-mental test, enhanced cued recall test, phonemic fluency, categorical fluency, digit span, counting the months backwards, clock-drawing, arithmetic operations, trail-making, cube copying, intersecting pentagons, and the interpretation of proverbs and similes. At one year, the patients were called by phone and questioned as to whether their cognitive complaints had persisted. Those patients with ongoing complaints were invited to the hospital and re-evaluated via cognitive tests. The results are presented in comparison with age-matched healthy controls (n=15). RESULTS: Almost all of the patients' scores were within the "normal" range. The Spontaneous recall of the patients was statistically significantly lower than the controls (p=0.03). Although there were decreases in executive functions and central processing speed (trail making-A, trail making-B and reciting the months backwards tests) in the patient group, these differences were not statistically significant (p=0.07;p=0.14 and p=0.22, respectively) compared to the controls. We observed that the cognitive complaints of the patients had disappeared by the one-year follow-up. CONCLUSION: In our patients with brain fog, most of whom had mild COVID-19, we observed that among all cognitive functions, memory domain was most affected compared to the controls. At the one-year follow-up, COVID-related brain fog had disappeared.
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The global outbreak of coronavirus disease 2019 (COVID-19) has affected the urban mobility of nations around the world. The pandemic may even have a potentially lasting impact on travel behaviors during the post-pandemic stage. China has basically stopped the spread of COVID-19 and reopened the economy, providing an unprecedented environment for investigating post-pandemic travel behaviors. This study conducts multiple investigations to show the changes in travel behaviors in the post-pandemic stage, on the basis of empirical travel data in a variety of cities in China. Specifically, this study demonstrates the changes in road network travel speed in 57 case cities and the changes in subway ridership in 26 case cities. Comprehensive comparisons can indicate the potential modal share in the post-pandemic stage. Further, this study conducts a case analysis of Beijing, where the city has experienced two waves of COVID-19. The variations in travel speed in the road network of Beijing at different stages of the pandemic help reveal the public's responses towards the varying severity of the pandemic. Finally, a case study of the Yuhang district in Hangzhou is conducted to demonstrate the changes in traffic volume and vehicle travel distance amid the post-pandemic stage based on license plate recognition data. Results indicate a decline in subway trips in the post-pandemic stage among case cities. The vehicular traffic in cities with subways has recovered in peak hours on weekdays and has been even more congested than the pre-pandemic levels;whereas the vehicular traffic in cities without subways has not rebounded to pre-pandemic levels. This situation implies a potential modal shift from public transportation to private vehicular travel modes. Results also indicate that commuting traffic is sensitive to the severity of the pandemic. This may be because countermeasures, e.g., work-from-home and suspension of non-essential businesses, will be implemented if the pandemic restarts. The travel speed in non-peak hours and on non-workdays is higher than pre-pandemic levels, indicating that non-essential travel demand may be reduced and the public's vigilance towards the pandemic may continue to the post-pandemic stage. These findings can help improve policymaking strategies in the post-pandemic new normal. © 2023 American Society of Civil Engineers.
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SARS-CoV-2 is a pandemic that affects road traffic flaw and crashes globally. This study attempted to compare the situation of road traffic crashes in the city of Budapest before and after the SARS-CoV-2 pandemic to better understand its long-term percussive effects. The study considers 12208 road traffic crashes that registered between 20 May 2018 – 31 December 2021. The rate and severity of road traffic crashes during the SARS-CoV-2 pandemic examined by using a percentage frequency distribution and a severity index. This study depicted that most crashes reported during the normal daytime between15:01-18:00 (peak hour). The study indicated that during the SARS-CoV-2 pandemic the road traffic crashes were reduced by 20.15%. A rear-end collision was one of the most common type of catastrophes highly registered. Road users, particularly drivers, heavily endorsed crashes. Even though the proportion of road traffic crashes caused by alcohol consumption was modest (6%), the rate of alcohol consumption and its concentration increased slightly during the SARS-CoV-2 pandemic. At the same time the number of crashes caused by high-speed traffic maneuvers reduced. Improper interpretation of road traffic signs, road pavement condition and failure to respect proper sight distance were influential reasons of road traffic crashes among the top. Meanwhile, the distributional impact of careless driving in the aftermath of the SARS-CoV-2 pandemic causes a shift in rank. Therefore, this study proved that during SARS-CoV-2 pandemics road traffic crashes reduced, the rate and concentration of alcohol consumption increased, and careless driving was encouraged.
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An increase in interest in research projects which involves the design of robotic systems that minimizes interactions between humans has been caused by the COVID-19 outbreak, as such technology can greatly benefit healthcare industries in preventing the spread of highly infectious diseases. The utilization of remote-controlled robots in many different fields, especially in the medical field is becoming more and more necessary. However, mobile robots are susceptible to both systematic and nonsystematic errors that cause deviations in its trajectory. In view thereof, the researchers explored the possibility of minimizing the trajectory errors through speed calibration. The differential drive robot was navigated to finish a five-meter linear path of forward and backward motion. The test was conducted with a default linear speed of 0.5 m/s in which a high trajectory error was observed. Upon changing the speed of the robot, the same trajectory test was conducted at four additional different speeds, namely;0.25 m/s, 0.35 m/s, 0.65m/s and 0.75 m/s. With the gathered data, the researchers conducted a linear least-squares regression model using MATLAB wherein there is only one predictor variable (speed of the robot) and one response variable (deviation). Based on the results, the researchers concluded that the speed of 0.35 m/s is the optimal speed in which the trajectory error of the robot is minimal. The researchers recommend improving the design of the caster wheels to minimize the effects of nonsystematic errors. © 2022 IEEE.
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The COVID-19 pandemic has escalated the risk of SARS-CoV-2 transmission in the dental practice, especially as droplet-aerosol particles are generated by high-speed instruments. This has heightened awareness of other orally transmitted viruses, including influenza and herpes simplex virus 1 (HSV1), which are capable of threatening life and impairing health. While current disinfection procedures commonly use surface wipe-downs to reduce viral transmission, they are not fully effective. Consequently, this provides the opportunity for a spectrum of emitted viruses to reside airborne for hours and upon surfaces for days. The objective of this study was to develop an experimental platform to identify a safe and effective virucide with the ability to rapidly destroy oral viruses transported within droplets and aerosols. Our test method employed mixing viruses and virucides in a fine-mist bottle atomizer to mimic the generation of oral droplet-aerosols. The results revealed that human betacoronavirus OC43 (related to SARS-CoV-2), human influenza virus (H1N1), and HSV1 from atomizer-produced droplet-aerosols were each fully destroyed by only 100 ppm of hypochlorous acid (HOCl) within 30 s, which was the shortest time point of exposure to the virucide. Importantly, 100 ppm HOCl introduced into the oral cavity is known to be safe for humans. In conclusion, this frontline approach establishes the potential of using 100 ppm HOCl in waterlines to continuously irrigate the oral cavity during dental procedures to expeditiously destroy harmful viruses transmitted within aerosols and droplets to protect practitioners, staff, and other patients.
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Background: With the emergence of the COVID-19 pandemic, many countries implemented policies that included movement restrictions, social distancing and school closures in order to control the spread of the virus. Even though these actions may have been necessary to save lives, there have been some unintended consequences that could affect future public health. Methods: The present study uses data from more than 24,500 Austrian elementary school children (51.2% male) that participated in a state-wide fitness evaluation program, which was initiated in the 2016/17 school year. In addition to body weight and height, data on cardiorespiratory endurance, muscular power, speed, agility, flexibility and object control were collected from three cohorts prior to the implementation of movement restrictions (school years: 2016/17, 2017/18, 2018/19) and one cohort in 2022, after the majority of COVID-19 policies had been lifted. Results: Body mass index percentiles were significantly higher in children post-COVID-19 (p < 0.01). Further, cardiorespiratory endurance, agility and flexibility were significantly lower post-COVID-19 compared to the years preceding movement restrictions (p ≤ 0.01), while absolute muscular strength was higher in the year 2022 (p < 0.01). Conclusion: Given the detrimental effects of COVID-19 policies on physical fitness in children, additional efforts are necessary that include versatile opportunities for physical activity and the promotion of physical fitness in order to modify the observed negative health trajectories and ensure future public health.
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Novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) is spreading rapidly around the world and has become a global pandemic. Meteorological factors have been recognized as one of the critical factors that influence the epidemiology and transmission of infectious diseases. In this context, the World Meteorological Organization and scholars at home and abroad have paid extensive attention to the relationships of environment and meteorology with COVID-19. This paper systematically collected and sorted out relevant domestic and foreign studies, and reviewed the latest research progress on the impact of environmental and meteorological factors on COVID-19, classifying them into typical meteorological factors (such as temperature, humidity, and wind speed), local environmental factors (such as indoor enclosed environment, ventilation, disinfection, and air conditioning), and air pollution. Current research evidence suggests that typical meteorological factors, local environmental factors, and air pollutants are closely related to the transmission of COVID-19. However, the results of different studies are still divergent due to uncertainty about the influencing mechanism, and differences in research areas and methods. This review elucidated the importance of environmental and meteorological factors to the spread of COVID-19, and provided useful implications for the control of further large-scale transmission of COVID-19 and the development of prevention and control strategies under different environmental and meteorological conditions.Copyright © 2022, Shanghai Municipal Center for Disease Control and Prevention. All rights reserved.
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The impact of the COVID pandemic has resulted in many people cultivating a remote working culture and increasing building energy use. A reduction in the energy use of heating, ventilation, and air-conditioning (HVAC) systems is necessary for decreasing the energy use in buildings. The refrigerant charge of a heat pump greatly affects its energy use. However, refrigerant leakage causes a significant increase in the energy use of HVAC systems. The development of refrigerant charge fault detection models is, therefore, important to prevent unwarranted energy consumption and CO2 emissions in heat pumps. This paper examines refrigerant charge faults and their effect on a variable speed heat pump and the most accurate method between a multiple linear regression and multilayer perceptron model to use in detecting the refrigerant charge fault using the discharge temperature of the compressor, outdoor entering water temperature and compressor speed as inputs, and refrigerant charge as the output. The COP of the heat pump decreased when it was not operating at the optimum refrigerant charge, while an increase in compressor speed compensated for the degradation in the capacity during refrigerant leakage. Furthermore, the multilayer perception was found to have a higher prediction accuracy of the refrigerant charge fault with a mean square error of ± 3.7%, while the multiple linear regression model had a mean square error of ± 4.5%. The study also found that the multilayer perception model requires 7 neurons in the hidden layer to make viable predictions on any subsequent test sets fed into it under similar experimental conditions and parameters of the heat pump used in this study.
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BACKGROUND: During the COVID-19 pandemic, rehabilitation providers and consumers adopted telehealth practices at unprecedented rates. Multiple prepandemic studies demonstrate the feasibility and comparable efficacy between in-clinic and remote treatment for certain impairments caused by stroke, such as upper extremity weakness and impaired motor function. However, less guidance has been available regarding gait assessment and treatment. Despite this limitation, safe and effective gait treatment is fundamental to optimizing health and well-being after stroke and should be considered a treatment priority, including during the COVID-19 pandemic. OBJECTIVE: This study explores the feasibility of using telehealth to deliver gait treatment using a wearable gait device, the iStride device, to stroke survivors during the 2020 pandemic. The gait device is used to treat hemiparetic gait impairments caused by stroke. The device alters the user's gait mechanics and creates a subtle destabilization of the nonparetic limb; therefore, supervision is required during its usage. Before the pandemic, treatment with the gait device had been provided in person to appropriate candidates using a combination of physical therapists and trained personnel. However, upon the emergence of the COVID-19 pandemic, in-person treatment was halted in adherence to pandemic guidelines. This study investigates the feasibility of 2 remote delivery treatment models with the gait device for stroke survivors. METHODS: Participants were recruited during the first half of 2020 after the onset of the pandemic and included 5 individuals with chronic stroke (mean age 72 years; 84 months post stroke). Four participants were previous gait device users who transitioned to the telehealth delivery model to continue their gait treatment remotely. The fifth participant performed all study-related activities, from recruitment through follow-up, remotely. The protocol included virtual training for the at-home care partner, followed by 3 months of remote treatment with the gait device. Participants were instructed to wear gait sensors during all treatment activities. To assess feasibility, we monitored the safety of the remote treatment, compliance with protocol activities, acceptability of the telehealth treatment delivery, and preliminary efficacy of the gait treatment. Functional improvement was measured using the 10-Meter Walk Test, the Timed Up and Go Test, and the 6-Minute Walk Test, and quality of life was assessed using the Stroke-Specific Quality of Life Scale. RESULTS: No serious adverse events occurred, and participants rated high acceptance of the telehealth delivery. Protocol compliance averaged 95% of treatment sessions, 100% of assessments, and 85% of sensor usage during treatment. After 3 months of treatment, the average improvement in each functional outcome exceeded the minimal clinically important difference or minimal detectable change value. CONCLUSIONS: Remote treatment delivery with the gait device appeared feasible with care partner support. Gait treatment using telehealth may be useful to offset negative immobility impacts for those requiring or preferring remote care during the pandemic or otherwise. TRIAL REGISTRATION: ClinicalTrials.gov NCT04434313; https://clinicaltrials.gov/ct2/show/NCT04434313.
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Background: Clinical studies suggest that warmer climates slow the spread of viral infections. In addition, exposure to cold weakens human immunity. Aim: This study describes the relationship between meteorological indicators, the number of cases, and mortality in patients with confirmed coronavirus disease 2019 (COVID-19). Patients and Methods: This was a retrospective observational study. Adult patients who presented to the emergency department with confirmed COVID-19 were included in the study. Meteorological data [mean temperature, minimum (min) temperature, maximum (max) temperature, relative humidity, and wind speed] for the city of Istanbul were collected from the Istanbul Meteorology 1st Regional Directorate. Results: The study population consisted of 169,058 patients. The highest number of patients were admitted in December (n = 21,610) and the highest number of deaths (n = 46) occurred in November. In a correlation analysis, a statistically significant, negative correlation was found between the number of COVID-19 patients and mean temperature (rho = -0.734, P < 0.001), max temperature (rho = -0.696, P < 0.001) or min temperature (rho = -0.748, P < 0.001). Besides, the total number of patients correlated significantly and positively with the mean relative humidity (rho = 0.399 and P = 0.012). The correlation analysis also showed a significant negative relationship between the mean, maximum, and min temperatures and the number of deaths and mortality. Conclusion: Our results indicate an increased number of COVID-19 cases during the 39-week study period when the mean, max, and min temperatures were consistently low and the mean relative humidity was consistently high.
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COVID-19 , Adult , Humans , COVID-19/epidemiology , Meteorological Concepts , Temperature , Retrospective Studies , Cold TemperatureABSTRACT
Objective: The coronavirus disease (COVID-19) is a problem for the health care systems of many countries around the world. Seasonal nature of influenza and other the respiratory viral diseases is commonly known. The nature of the relationship between the frequency of registration of cases of COVID-19 and natural factors is still being studied by researchers. The purpose is to determine the influence of air temperature, relative humidity, wind speed, and atmospheric pressure on the incidence of the coronavirus disease COVID-19 in the conditions of Ukraine. Materials and methods. Official reports of the Ministry of Health of Ukraine and data from daily monitoring of meteorological indicators conducted by the Sumy Regional Hydrometeorology Center were used in the paper. Descriptive and analytical ways of epidemiological method of investigation were applied. The search for parameters of interrelation between the frequency of registration of COVID-19 cases and meteorological cases took place using of program "Statistica", namely the relevant tools of this program: "Analysis"/ "Multiple regression". Results and Discussion: In the period under study from March 25, 2020 to December 31, 2021 in Sumy Oblast of Ukraine, three waves of rise in the incidence were registered. In the third wave of rise in the incidence, in autumn 2021 the frequency of registration of COVID-19 cases reached 1684.9 per 100 thousand of people, despite the fact that almost 70 % of the population had already recovered or were vaccinated. Meteorological factors in the conditions of Ukraine have little influence on the rate of spread of COVID-19. The value of multiple correlation coefficients was within those limits, which are considered moderate in terms of influence. A moderate inverse correlation was established between the frequency of registration of COVID-19 cases and indicators of air temperature, and a direct correlations-with indicators of relative air humidity. Conclusion(s): In the conditions of Ukraine, the studied meteorological factors (air temperature, relative humidity, wind speed, atmospheric pressure) indirectly influenced the intensity of the epidemic process of COVID-19. the strength of this influence was either weak or moderate.Copyright © 2023, Ibn Sina Trust. All rights reserved.
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In May - a month behind the usual schedule - the first semester of the 2020 academic year commenced as a remote learning endeavor to prevent the spread of coronavirus disease. In this paper, I report examples of remote learning on recording and their problems. Tokyo University of the Arts adopted Google Classroom as a learning management system - a necessary framework for remote learning. It provides the faculty and students with instructions on using the classroom to prepare for the first semester. We also shared information on conducting real-time remote lectures with the help of web conferencing systems (Google Meet, Zoom, etc.). In the recording class, it was necessary to send sound samples with high quality, so I tried various sound transmission software but found that it depended greatly on the Internet environment of the students on the receiving end. Therefore, it was necessary to use both online and on-demand. Finally, it became clear what was not being communicated online. © ICA 2022.All rights reserved
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We develop a new analytical solution of a three-dimensional atmospheric pollutant dispersion. The main idea is to subdivide vertically the planetary boundary layer into sub-layers, where the wind speed and eddy diffusivity assume average values for each sub-layer. Basically, the model is assessed and validated using data obtained from the Copenhagen diffusion and Prairie Grass experiments. Our findings show that there is a good agreement between the predicted and observed crosswind-integrated concentrations. Moreover, the calculated statistical indices are within the range of acceptable model performance.
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Background: Neurocognitive dysfunction is common in long COVID and in people living with HIV (PWH). It is unknown whether PWH experience different disturbances in neurocognitive function following COVID-19 compared to HIVseronegative people. Method(s): The amfAR-Johns Hopkins University COVID Recovery Study is a prospective observational cohort study consisting of four groups: participants who had SARS-CoV-2 infection for the first time within 30 days prior to enrollment with HIV (PWH, arm 1) and without HIV (arm 2);participants with no history of SARS-CoV-2 infection with HIV (arm 3) and without HIV (arm 4). 93.5% of the cohort had received a COVID-19 vaccine prior to enrollment. Cognitive tests were administered at 1-and 4-months post symptom onset (arms 1-2) or post-enrollment (arms 3-4) in seven domains. Age standardized scores (all tests) and age-sex-and education-standardized scores (verbal fluency) were obtained. Standardized scores were compared using the Mann-Whitney U Test and the Kruskal-Wallis test. Result(s): PWH scored lower than HIV-seronegative participants at 1 and 4 months post-COVID on three tests: the Hopkins Verbal Learning Test-Revised (HVLT-R) learning (M1, p=0.011, M4, p=0.015), HVLT-R memory (M1, p=0.029, M4, p=0.007), and category-cued verbal fluency (VF;M1&4, p< 0.001). For the majority of timepoints, PWH who were post-COVID produced equivalent scores as PWH who never had COVID (p-levels > 0.05). Comparing post-COVID HIV-seronegative people to those who never had COVID, post-COVID participants scored lower than never-COVID participants on the Oral Trail Making Test part A (OTMT) test of processing speed at month 1 (p=0.033). Between month 1 and 4, HIV-seronegative people who were post-COVID showed improvements in HVLT-R Recognition (p=0.039), OTMT A (p=0.003), and OTMT B test of executive function (p=0.032). Conclusion(s): Neurocognitive scores in PWH were independent of COVID status, suggesting that higher frequencies of post-COVID neurocognitive dysfunction in PWH compared to HIV-seronegative people are due to HIV-associated factors more so than COVID. HIV-seronegative, post-COVID people demonstrate diminished recognition memory, processing speed, and executive function at 1 month post-COVID that improves by 4 months. Post-COVID neurocognitive dysfunction is present, if temporary, even in a highly vaccinated cohort of people.
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There has been an increase of interest and demand in the usage of logistic indoor service robots that are designed to minimize interactions between humans due to the occurrence of the COVID-19 outbreak. The application of the rising technology in the medical sector has great benefits in the industry, such as the prevention of the spread of highly infectious diseases using distance as a factor. Rooting from the purpose of the said robot, the main focus should be the ease of navigation through achieving the desired trajectory, in order to maximize the functionality, prevent collision, reduce user maneuvering difficulties, and such. Hence, this paper is focused on improving the trajectory errors on the robot navigation performance based on different control system designs specifically, a physical joystick controller and a mobile-based Bluetooth application controller. The design of the joystick is based on a pivot as its base which is directed to all angles and the design of the Bluetooth app is based on fourdirectional buttons that will operate upon clicking, and switching to other buttons to change commands. With this, the researchers conducted linear path and rotational tests using both remote control modes that are based on five varying speed values of 0.75 m/s, 0.5m/s, 0.35m/s, 0.25m/s, and 0.15 m/s. Based on the data analysis, the yielded results showed that using the Bluetooth app lowers the robot's trajectory error by 50% to 60% compared to using ajoystick to navigate to the desired point. Thus, the researchers concluded that the design of a control system greatly affects the robot navigation in achieving the desired trajectory. Considering the nonsystematic errors, a calibration based on the hardware structure design specifically on the caster wheel is recommended. © 2023 IEEE.
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Introduction: The first year of the COVID-19 pandemic presented a series of stressors that could relate to psychological difficulties in children and adolescents. Executive functioning (EF) supports goal achievement and is associated with life success, and better outcomes following early life adversity. EF is also strongly related to processing speed, another predictor of life outcomes. Methods: This longitudinal study examined 149 youths' pre-pandemic EF and processing speed abilities as predictors of self-reported emotional, cognitive, and social experiences during the first year of the COVID-19 pandemic. EF and processing speed were measured with a total of 11 behavioral tasks. The COVID-era data was collected during two timepoints, during early (May-July 2020) and mid- (January-March of 2021) pandemic. Results: Better pre-pandemic EF skills and processing speed abilities predicted more mid-COVID-19 pandemic emotional and cognitive difficulties. On the other hand, better switching (a subcomponent of EF) and processing speed abilities predicted more mid-pandemic social interactions. EF and processing speed abilities did not relate to the well-being reports from the initial months of the pandemic. Our EF - but not processing speed - results were largely maintained when controlling for pre-pandemic mental health burden, socioeconomic status (SES), and gender. Discussion: Better cognitive abilities may have contributed to worse mid-pandemic functioning by supporting the meta-cognition needed for attending to the chaotic and ever-changing pandemic news and advice, leading to higher stress-induced worry and rumination. Our study highlights a potential downside of higher EF - often largely viewed as a protective factor - in youth.
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This study proposes two new regime-switching volatility models to empirically analyze the impact of the COVID-19 pandemic on hotel stock prices in Japan compared with the US, taking into account the role of stock markets. The first model is a direct impact model of COVID-19 on hotel stock prices; the analysis finds that infection speed negatively affects Japanese hotel stock prices and shows that the regime continues to switch to high volatility in prices due to COVID-19 until September 2021, unlike US stock prices. The second model is a hybrid model with COVID-19 and stock market impacts on the hotel stock prices, which can remove the market impacts on regime-switching volatility; this analysis demonstrates that COVID-19 negatively affects hotel stock prices regardless of whether they are in Japan or the US. We also observe a transition to a high-volatility regime in hotel stock prices due to COVID-19 until around summer 2021 in both Japan and the US. These results suggest that COVID-19 is likely to affect hotel stock prices in general, except for the influence of the stock market. Considering the market influence, COVID-19 directly and/or indirectly affects Japanese hotel stocks through the Japanese stock market, and US hotel stocks have limited impacts from COVID-19 owing to the offset between the influence on hotel stocks and no effect on the stock market. Based on the results, investors and portfolio managers should be aware that the impact of COVID-19 on hotel stock returns depends on the balance between the direct and indirect effects, and varies from country to country and region to region.
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Highway fatalities are a leading cause of death in the U.S. and other industrialized countries. Using highly detailed crash, speed, and flow data, we show highway travel and motor vehicle crashes fell substantially in California during the response to the COVID-19 pandemic. However, we also show the frequency of severe crashes increased owing to lower traffic congestion and higher highway speeds. This "speed effect" is largest in counties with high pre-existing levels of congestion, and we show it partially or completely offsets the "VMT effect" of reduced vehicle miles traveled on total fatalities. During the first eleven weeks of the COVID-19 response, highway driving decreased by approximately 22% and total crashes decreased by 49%. While average speeds increased by a modest 2 to 3 mph across the state, they increased between 10 and 15 mph in several counties. The proportion of severe crashes increased nearly 5 percentage points, or 25%. While fatalities decreased initially following restrictions, increased speeds mitigated the effect of lower vehicle miles traveled on fatalities, yielding little to no reduction in fatalities later in the COVID period.
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Stay-at-home policies in response to COVID-19 transformed high-volume arterials and highways into lower-volume roads, and reduced congestion during peak travel times. To learn from the effects of this transformation on traffic safety, an analysis of crash data in Ohio's Franklin County, U.S., from February to May 2020 is presented, augmented by speed and network data. Crash characteristics such as type and time of day are analyzed during a period of stay-at-home guidelines, and two models are estimated: (i) a multinomial logistic regression that relates daily volume to crash severity; and (ii) a Bayesian hierarchical logistic regression model that relates increases in average road speeds to increased severity and the likelihood of a crash being fatal. The findings confirm that lower volumes are associated with higher severity. The opportunity of the pandemic response is taken to explore the mechanisms of this effect. It is shown that higher speeds were associated with more severe crashes, a lower proportion of crashes were observed during morning peaks, and there was a reduction in types of crashes that occur in congestion. It is also noted that there was an increase in the proportion of crashes related to intoxication and speeding. The importance of the findings lay in the risk to essential workers who were required to use the road system while others could telework from home. Possibilities of similar shocks to travel demand in the future, and that traffic volumes may not recover to previous levels, are discussed, and policies are recommended that could reduce the risk of incapacitating and fatal crashes for continuing road users.