COVID-19 pandemic, Russia-Ukraine conflict and shale gas development: Evidence from fractional integration.

Although there are papers on the persistence of energy series including the persistence of shale gas, the impact of recent developments such as the Covid-19 pandemic and Russia-Ukraine conflict have been rarely explored in the existing literature This paper examines the structure of shale gas production in the U.S. by looking at the degree of persistence across different areas, with the aim to determine if shocks in the series are permanent or transitory.

CO emissions in Latin America: a time series perspective based on fractional integration.

This article deals with the analysis of [Formula: see text] emissions in Latin America by using a long memory process based on fractional integration. Using data of [Formula: see text] emission and [Formula: see text] emissions per capita, for 32 Latin American and Caribbean countries, the results show significant differences according to the variable examined, the model used, and the country under examination. In particular, for the [Formula: see text] emissions, mean reversion is found in Belize and also under some circumstances in Antigua and Barbuda, Colombia, Dominica, Dominican Republic, Ecuador, Grenada, Honduras, Nicaragua, Panama, Peru, and Uruguay.

Trends in road accidents on Brazil's highways: Evidence of persistence using fractional integration.

This paper deals with the analysis of trends in road accidents on highways in Brazil. We use time series techniques based on fractional integration that allow us to determine if exogenous shocks in the data have transitory or permanent effects depending on the order of integration of the series. Our results indicate that a low degree of long memory was detected in the series with shocks having thus transitory effects over time.

Measuring Persistence in the US Equity Gender Diversity Index.

An analysis of the SPDR SSGA Gender Diversity Index ETF using fractional integration or I(d) techniques and daily data from 8 March 2016 to 8 January 2021, reveals that the series is highly persistent with an order of integration smaller than, though very close to 1. However, when estimating d recursively across subsamples, two peaks can be observed. The first peak appears in the sample with 679 observations (ending at 26 December 2018) and the second one occurs in the sample with 974 observations and ending at 28 February 2020, which shows the most significant change in d, moving from values within the I(1) interval to values significantly above 1.

The impact of containment measures and monetary and fiscal responses on US financial markets during the COVID-19 pandemic.

This paper analyses the effects of containment measures and monetary and fiscal responses on US financial markets during the Covid-19 pandemic. More specifically, it applies fractional integration methods to analyse their impact on the daily S&P500, the US Treasury Bond Index (USTB), the S&P Green Bond Index (GREEN) and the Dow Jones (DJ) Islamic World Market Index (ISLAM) over the period 1/01/2020-10/03/2021. The results suggest that all four indices are highly persistent and exhibit orders of integration close to 1.

Stock market responses to COVID-19: The behaviors of mean reversion, dependence and persistence.

We examine stock market responses during the COVID-19 pandemic period using fractional integration techniques. The evidence suggests that stock markets generally follow a synchronized movement before and the stages of the pandemic shocks. We find while mean reversion significantly declines, the degree of persistence and dependence has been increased in the majority of the stock market indices in whole sample analysis covering the period of August 02, 2019 and July 09, 2020.

Gold and silver as safe havens: A fractional integration and cointegration analysis.

This paper investigates whether gold and silver can be considered safe havens by examining their long-run linkages with 13 stock price indices. More specifically, the stochastic properties of the differential between gold/silver prices and 13 stock indices are analysed applying fractional integration/cointegration methods to daily data, first for a sample from January 2010 until December 2019, then for one from January 2020 until June 2022 which includes the Covid-19 pandemic. The results can be summarised as follows.

Us vehicles sales. Evidence of persistence after COVID-19.

In this paper, the sales of vehicles in the US are examined to understand if the shock caused by the current COVID-19 pandemic has had permanent or transitory effects on its subsequent evolution. Using monthly data from January 1976 until April 2021 and fractional integration methods, our results indicate that the series reverts and the shocks tend to disappear in the long run, even when they appear to be long lived. The results also indicate that the COVID-19 pandemic has not increased the degree of persistence of the series but, unexpectedly, has slightly reduced its dependence.

A multivariate causality analysis of CO emission, electricity consumption, and economic growth: Evidence from Western and Central Africa.

The vector error correction model is used to examine the short- and long-run impacts of electricity consumption and economic growth on CO emissions in Western and Central Africa from 1970 to 2020. This paper adopted time series vector error correction model (VECM) approach to conduct stationarity test, cointegration test, stability test, and Granger causality test. Cointegration tests are used to examine the long-run impact of electricity consumption and economic growth on CO emissions.

Mean reversion and convergence of ecological footprint in the MENA region: evidence from a fractional integration procedure.

This paper deals with the analysis of mean reversion and convergence of the ecological footprint (EF) in the MENA region. Using a long memory model based on fractional integration, we find that the results are very heterogeneous across countries depending on the assumptions made on the error term and the use of original versus logged data. Nevertheless, some conclusions can be obtained.

Temperature and precipitation in the US states: long memory, persistence, and time trend.

This paper investigates the time series properties of the temperature and precipitation anomalies in the contiguous USA by using fractional differentiation. This methodology allows to capture time trend components along with properties such as long-range dependence and the degree of persistence. For aggregated data, we find out that long memory is present in both precipitation and temperature since the integration order is significantly positive in the two cases.

Time trends and persistence in PM in 20 megacities: evidence for the time period 2018-2020.

The degree of persistence in daily data for PM in 20 relevant megacities such as Bangkok, Beijing, Mumbai, Calcutta, Canton, Dhaka, Delhi, Jakarta, London, Los Angeles, Mexico City, Moscow, New York, Osaka. Paris, Sao Paulo, Seoul, Shanghai, Tientsin, and Tokyo is examined in this work. The analysis developed is based on fractional integration techniques.

Inequality Persistence of 21 OECD Countries from 1870 to 2020: Linear and Non-Linear Fractional Integration Approaches.

This paper investigates inequality persistence in a group of 21 OECD countries using linear and non-linear fractionally integrated methods. Using linear models, the results show that the series are strongly persistent which implies lack of average reversal and permanency of shocks. Mean reversion is only found in the case of Finland and partial evidence of mean reversion is detected for Belgium, Greece, Austria and the Netherlands.

The COVID-19 pandemic and the degree of persistence of US stock prices and bond yields.

This paper analyses the possible effects of the Covid-19 pandemic on the degree of persistence of US monthly stock prices and bond yields using fractional integration techniques. The model is estimated first over the period January 1966-December 2020 and then a recursive approach is taken to examine whether or not persistence has changed during the following pandemic period (up to February 2021). We find that the unit root hypothesis cannot be rejected for stock prices while for bond yields the results differ depending on the maturity date and the specification of the error term.

The relationship between prices and output in the UK and the US.

This paper aims to provide new evidence on the relationship between prices and output in both the US and the UK (which is important to discriminate between different macroeconomic theories) by focusing on the long run. For this purpose, it applies fractional integration and long-range dependence techniques that are more general than the standard modelling approach based on the stationary  (0) versus nonstationary  (1) dichotomy which has been used in previous studies. All series appear to be highly trended and to exhibit high degrees of integration and persistence, especially in the case of CPI.

Globalization, long memory, and real interest rate convergence: a historical perspective.

This paper investigates whether the real interest rate parity (RIRP) is valid during the three waves of globalizations that occurred in the last 150 years (1870-1914, 1944-1971, 1989 to the present). If any, these periods should favor RIRP, since globalization is a process where economies and financial markets become increasingly integrated into a global economic system. In contrast to the existing literature, we model the departures from RIRP as a long-term memory process and apply fractional integration methods on a sample of real interest rate differentials of seven developed countries: France, Germany, Holland, Italy, Japan, Spain, and the UK across the three globalization waves paired against the USA.

Unemployment persistence in Europe: evidence from the 27 EU countries.

This paper investigates unemployment persistence in the 27 EU member states by applying fractional integration methods to quarterly data (both seasonally adjusted and unadjusted) from 2000q1 to 2020q4. The obtained evidence points to high levels of persistence in all cases. With seasonally adjusted data, a small degree of mean reversion is found in the case of Belgium, Luxembourg and Malta, but this evidence disappears under the assumption of weakly correlated disturbances.

Pandemic episodes, CO emissions and global temperatures.

This paper deals with the relationship between the CO emissions and the global temperatures across the various pandemic episodes that have been taken place in the last 100 years. To carry out the analysis, first we conducted unit root tests finding evidence of nonstationary I(1) behavior, which means that a shift in time causes a change in the shape of distribution. However, due to the low statistical power of unit root tests, we also used a methodology based on long memory and fractional integration.

Atmospheric pollution in the ten most populated US cities. Evidence of persistence.

The degree of persistence in daily PM and O in the ten most populated US cities, namely New York, Los Angeles, Chicago, Houston, Phoenix, Philadelphia, San Antonio, San Diego, Dallas and San Jose is examined in this work. We employ a methodology based on fractional integration, using the order of integration as a measure of the degree of persistence. Using data for the time period from January 1, 2019 to December 31, 2020, our results indicate that fractional integration and long memory features are both present in all the examined cases, with the integration order of the series being constrained in the (0, 1) interval.

Modelling stock market data in China: Crisis and Coronavirus.

Global financial markets experienced distinct collapses during the global financial crisis in 2008 and the COVID-19 pandemic in 2020, and similarity in the underlying nature is still a hot topic to be investigated. This paper investigates their degree of persistence in order to detect whether the shocks affecting them have temporary or permanent effects by examining the closing prices of the Shanghai and Shenzhen Composite Indices from 1991 to 2020. The results before the coronavirus indicate large degrees of persistence with shocks having permanent effects, while during the coronavirus the results indicate a mean reversion with shocks having temporary effects.

Persistence and sustainability of fishing grounds footprint: Evidence from 89 countries.

This paper focusses on the examination of the fishing ground footprint in a group of 89 countries using fractional integration. The fishing ground footprint is one of the components of the ecological footprint. Nevertheless, it has not been investigated very much from an empirical viewpoint.

Testing fractional unit roots with non-linear smooth break approximations using Fourier functions.

In this paper, we present a testing procedure for fractional orders of integration in the context of non-linear terms approximated by Fourier functions. The test statistic has an asymptotic standard normal distribution and several Monte Carlo experiments conducted in the paper show that it performs well in finite samples. Various applications using real life time series, such as US unemployment rates, US GNP and Purchasing Power Parity (PPP) of G7 countries are presented at the end of the paper.

Under-5 Mortality Rates in G7 Countries: Analysis of Fractional Persistence, Structural Breaks and Nonlinear Time Trends.

This paper deals with the analysis of the under-5 mortality rate series in the G7 countries by using fractional integration techniques, including structural breaks and potential nonlinearities in the data. Several features were detected in the results: Firstly, we observed that for the neonatal data, the order of integration is equal to or higher than one in all cases, contrary to what happens for the remaining cases (< 1- < 5 years) where mean reversion is found in many cases, especially as we increase the age of death. Thus, shocks affecting the neonatal (< 1 month from delivery) mortality rates will have permanent effects requiring special attention to recover the original trends.

Stochastic convergence of renewable energy consumption in OECD countries: a fractional integration approach.

In this article, we have examined the hypothesis of convergence of renewable energy consumption in 27 OECD countries. However, instead of relying on classical techniques, which are based on the dichotomy between stationarity I(0) and nonstationarity I(1), we consider a more flexible approach based on fractional integration. We employ both parametric and semiparametric techniques.