1,044 research outputs found
Long-Term Effect of Non-Sever COVID-19 on Pulmonary Function, Functional Capacities and Physical Activities. A Cross-Section Study.
No full textBackground: The COVID-19 has serious consequences on different body systems particularly the respiratory system with its impact on pulmonary function, functional capacities, physical activities, and personal performance. Objective: The aim of this study was to investigate the long-term effect of COVID-19 on pulmonary function, functional capacities, and physical activities in patients with non-sever COVID-19, and to evaluate time effect on the associated consequences. Methods: One hundred and sixty individuals were selected to participate in a cross-section study. Group-I: Eighty male and female patients with non-sever COVID-19 at least 3 months after the recovery time. Group-II: Eighty male and female matched participants. The spirometer, six-minute walking test (6MWT), and International Physical Activity Questionnaire (IPAQ) were used to assess pulmonary function, functional capacities, and physical activities respectively. Shapiro-Wilk’s test was used to test the normality of data. The Mann-Whitney and Independent t-tests were used to compare the significant differences between both groups. Results: The results show significant differences in pulmonary function, functional capacities, and physical activities, between both COVID-19 and matched groups. Conclusion: Pulmonary function, functional capacities, and physical activities are negatively influenced by COVID-19 as long-term consequences indicating the need for extended health care, and prescription of proper rehabilitative training programs for those patients whatever severity degree of infection or history of hospitalization. Gaining the deepest knowledge enables physical therapists to tailor the proper rehabilitative training programs for such patients. Clinical implications: Outcome reflections of current results raise awareness of physical therapists during prescription of the proper rehabilitative training programs, for such patients
Turkish Stock Market from Pandemic to Russian Invasion, Evidence from Developed Machine Learning Algorithm
No full textIn recent time, the two significant events; Coronavirus epidemic and Russian invasion are effecting all over the world in various aspects; healthily, economically, environmentally, and socially, etc. The first event has brought uncertainties to the economic situation in most countries based on the epidemic transmission. In addition to that, on 24th February 2022 the Russian invasion of Ukraine affected negatively almost all stock markets all over the world, but the effects are heterogeneous across countries according to their economic-political relationship or neighbourhood, etc. Due to that, the stock market price in Turkey has been affected dramatically over that period. This empirical study is the first attempts to explore the impact of Coronavirus epidemic and Russian invasion on the stock market index XU100 in Turkey by applying the developed statistical method namely elastic-net regression based on empirical mode decomposition which can precisely tackle the nonstationary and nonlinearity data. Then we performed the robustness check by applying a nonlinear techniques Markov switching regression. The data are collected from the beginning of the epidemic in Turkey from March 11, 2020 until May 31, 2022. The finding reveals that there is significant effect of the Coronavirus spreading on the Turkish stock market index, particularly during the first wave. Then after the Russian Invasion the XU100 index is effected more negatively. As the credit default swap and TL reference interest rate have a negative impact but the foreigner exchange rate has a positive significant impact on the XU100 index, and it varies according to the period of short term and long term. Moreover, the results obtained by using the robustness check shows a robust and consistent finding. In conclusion, understanding the impact of Coronavirus pandemic and Russian invasion on the Turkish stock market can provide important implications for investors, financial sectors, and policymakers
Association between coronavirus cases and seasonal climatic variables in Mediterranean European Region, evidence by panel data regression
No full textThe coronavirus pandemic is one of the most fast-spreading diseases in the history, and the transmission of this virus has crossed rapidly over the whole world. In this study, we intend to detect the effect of temperature, precipitation, and wind speed on the Coronavirus infected cases throughout climate seasons for the whole year of epidemic starting from February 20, 2020 to February 19, 2021 with considering data patterns of each season separately; winter, spring, summer, autumn, in Mediterranean European regions, whereas those are located at the similar temperature zone in southern Europe. We apply the panel data approach by considering the developed robust estimation of clustered standard error which leads to achieving high forecasting accuracy. The main finding supports that temperature and wind speed have significant influence in reducing the Coronavirus cases at the beginning of this epidemic particularly in the first-winter, spring, and early summer, but they have very weak effects in the autumn and second-winter. Therefore, it is important to take into account the changes throughout seasons, and to consider other indirect factors which influence the virus transmission. This finding could lead to significant contributions to policymakers in European Union and European Commission Environment to limit the Coronavirus transmissions. As the Mediterranean region becomes more crowded for tourism purposes particularly in the summer season
A validation forecast using robust estimators into environmental application
No full textInvestigating the effect of energy consumption and economic growth on carbon dioxide emissions has received much effort due to the global environmental issues. Multiple methods are used to explain that relationship, but findings are conflicting, that might due to inaccurate chosen statistical methods and the frequent presence of outliers in the data. The main objective of this study is to shed light on obtaining the best model in detecting that relationship using various robust estimators (M, Median, S and MM-estimator) against OLS in the presence of different types of outliers in the panel data, then, models are evaluated by using train-test forecasting approach. The panel data include 29 countries, divided into two groups based on the economic level, 17 developed countries versus 12 developing countries from 1960 to 2008. The main findings support that the robust estimators have better properties than the OLS estimator when the dataset has outliers. The M-estimator is the best robust estimator which could fit the data in the presence of different types of outliers. The energy consumption and economic growth have negative and positive relationship with CO2 emissions, respectively. Moreover, developing countries affect CO2 emissions more than the developed countries. In conclusion, energy consumption contributes to higher environmental degradation particularly in CO2 emissions, thus it is recommended to policy makers to consider it in their policies for a better future
Essays in statistical arbitrage
No full textThis three-paper thesis explores the important relationship between arbitrage and price efficiency. Chapter 3 investigates the risk-bearing capacity of arbitrageurs under varying degrees and types of risk. A novel stochastic process is introduced to the literature that is capable of jointly capturing fundamental risk factors which are absent from extant specifications. Using stochastic optimal control theory, the degree to which arbitrageurs' investment behaviour is affected by aversion to these risks is analytically characterized, as well as conditions under which arbitrageurs cut losses, effectively exacerbating pricing disequilibria. Chapter 4 explores the role of arbitrage in enforcing price parity between cross-listed securities. This work employs an overlooked mechanism by which arbitrage can maintain parity, namely pairs-trading, which is cheaper to implement than the mechanism most commonly employed in the literature on cross-listed securities. This work shows that arbitrage is successful at enforcing parity between cross-listed securities, and also documents the main limits to arbitrage in this market setting. Chapter 5 examines the extent to which arbitrage contributes to the flow of information across markets. It is shown that microscopic lead/lag relationships of the order of a few hundred milliseconds exist across three major international index futures. Importantly, these delays last long enough, and induce pricing anomalies large enough, to compensate arbitrageurs for appropriating pricing disequilibria. These results accord with the view that temporary disequilibria incentivise arbitrageurs to correct pricing anomalies
Regional economic convergence in federation contexts: a comparative analysis of Brazil and the European Union
No full textThis article examines regional economic convergence in two federal contexts: Brazil and the European Union. Despite many differences, in the last decades these two economies have shown irregular economic growth and been facing economic inequalities, launching public policies to reduce them. We analyse the tendencies of regional convergence within these economies between 2002 and 2019, focusing on !-convergence, absolute convergence, convergence clubs and the transitional behaviour of club members. The results show that in both cases convergence occurs, but at a slow rhythm, especially in the European Union
Ultra High Frequency Algorithmic Arbitrage Across International Index Futures
No full textWe show that persistent lead-lag relationships spanning mere fractions of a seccond exist in all three possible pairings of the S&P500, FTSE100, and DAX futures contracts. These relationships exhibit clear intraday patterns which help us to forecast mid-quote changes in lagging contracts with directional accuracy in excess of 85%. A simple algorithmic trading strategy exploiting these relations yields economically significant profits which are robust to market impact costs and the bid-ask spread. We find that price slippage and infrastructure costs are our most important limits to arbitrage. Our results support the Grossman and Stiglitz (1976, 1980) view that informational ine?fficiencies incentivize arbitrageurs to eliminate mispricings
Arbitrage and the law of one price in the market for American depository receipts
No full textOurs is the fi?rst paper to highlight pairs trading as the main price-correcting mechanism by which arbitrage can maintain stock-ADR parity. We show that arbitraging stock-ADR pairs extracts small per-trade pro?fits which accumulate to a substantial aggregate return. The observed strong tendency of pricing disequilibria to mean-revert, along with the two-way convertibility between stocks and ADRs, mean that arbitrageurs face minimal risks toward price divergence. They do, however, face uncertainty about the duration of individual trades. The magnitude of this uncertainty relates directly to the profi?t target arbitrageurs set after a long/short position is established. This fact can explain why some disequilibria go unexploited. Overall, our work provides evidence against automatically e?fficient prices, and supports the view that mispricings incentivize arbitrageurs to enforce market efficiency
Real time H.F. Channel estimation
No full textThe necessity of real time H. F. channel estimation for fully controlling an adaptive system is shown in this thesis. The use of C. W. pilot tones for channel estimation is discussed in detail. The phase perturbations and amplitude variations of a received C. W. pilot tone, propagating through the ionosphere, are analysed to give direct measurement of the propagation parameters. The effect of propagation conditions on the signal distribution is discussedand introduced In the analysis. The general expressions, which define each type of propagation condition, are deduced and the theoretical values are computed. The practical implementation using a microprocessor technique is shown. The practical results obtained by laboratory simulation are compared with the theoretical analysis for the different types of propagation conditions.</p
Regional economic convergence in federation contexts: a comparative analysis of Brazil and the European Union
No full textThis article examines regional economic convergence in two federal contexts: Brazil and the European Union. Despite many differences, in the last decades these two economies have shown irregular economic growth and been facing economic inequalities, launching public policies to reduce them. We analyse the tendencies of regional convergence within these economies between 2002 and 2019, focusing on σ-convergence, absolute convergence, convergence clubs and the transitional behaviour of club members. The results show that in both cases convergence occurs, but at a slow rhythm, especially in the European Union
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