Kwiatkowski-Phillips-Schmidt-Shin Research Articles

Mentorship in Training of Minimally Invasive Pancreatoduodenectomy

Introduction: Laparoscopic pancreatoduodenectomy (LPD)is one of the most challenging minimally invasive procedures; training is not standardized. We sought to evaluate immediate postoperative outcomes of three surgeons performing LPD in the same institution, compared according to their training: self-learned, instructor-led and on-site proctoring. Methods: From 2007-2021, three different surgeons performed 404 LPD(43.5%male, median age 62(29-82)years, median ASA score 2.3(2-3),median Charlson score 1.7 (1-2)).The first surgeon started total LPD without a previous specific training program (self-learned). The second assisted the first surgeon for 50 procedures before performing his first 10 procedures under the mentoring of the first surgeon. The third surgeon was trained by on-site proctoring and performed the procedure by a hybrid technique. Morbidity was evaluated according to Clavien-Dindo. The critical slope of operative time, morbidity and blood loss was measured during the first 40 consecutive LPDs analyzed by CUSUM methodology and compared by the Mann-Whitney test. The Kwiatkowski-Phillips-Schmidt-Shin(KPSS)test was used to evaluate the stationarity. Results: The number of procedures performed was 257, 120 and 43, respectively. The cut-off (learning plateau) values(60 min forCUSUM methodology)for the three parameters was 19, 9and7, respectively. The p value for KPSS was 0.01. Median operative time was 492(423-571),497(408-615)and515(448-581)minutes, respectively(p = 0.322).Severe morbidity(grades 3a - 5)was 24%, 45% and 47% (p = 0.33),respectively. Intraoperative blood loss was 525(237-900),200(100-300)and200(100-300)ml(p = 0.01),respectively. The only statistically significant difference in perioperative data among the 3 surgeons was intraoperative blood loss. Conclusion: On-site proctoring resulted in less intraoperative blood loss during LPD during training.On-site proctoring should be further evaluated and included in training program for LPD.

Efficient Market Hypothesis for Malaysian Extreme Stock Return: Peaks Over A Threshold Method

This paper presents investigation on the efficient market hypothesis of extreme stock return based on peaks over threshold method, by application of 10% Value at risk (VaR) quantile threshold level. The efficient market hypothesis (EMH) in the stock market index is validated by utilising autocorrelation, Kwiatkowski Phillips Schmidt Shin (KPSS), and variance ratio tests. The tests constituted of daily, extreme maximum and minimum, and three sub-periods data reflecting different economic condition in the market. Results indicated the strong influences of the financial crisis in the series movement. Mixed evidences were acquired; nonetheless, the overall results show that the Malaysia extreme stock return does not follow a random walk, only the series during the crisis and recovery period are in weak-form market efficiency.

The role of environmental, social, and governance responsibilities and economic development on achieving the SDGs: evidence from BRICS countries

Sustainable development goal (SDG) achievement has gained increasing trend due to the current economic uncertainty that demands the attention of scholars, practitioners, and regulators. Hence, the study examines the environmental, social, and governance (ESG) responsibilities and economic development such as economic growth, net national income and FDI on the SDG achievements in BRICS countries. The secondary data is considered for the study which was collected from various resources like SDG reports published by the united nation and World Bank Indicators (WDI) from 1991 to 2020. The current research has checked them without structural breaks stationarity using Dickey-Fuller (ADF) test, Phillips–Perron (PP) test, and Kwiatkowski–Phillips–Schmidt–Shin (KPSS), while stationarity with structural breaks has been examined using the ‘zivot-andrews’ test. The study also employed the ARDL technique to verify the association among the constructs. The findings revealed that ESG responsibilities, economic growth, net national income, FDI, and inflation positively correlate with SDG achievements in BRICS countries. This article provides help to the regulators while making policies related the SDG achievement.

Loan performance and lending rate: Testing the existence of adverse selection in the Nigerian credit market

Leaning on the loan pricing theory, this study provided empirical proof of the existence of adverse selection in the Nigerian credit market using the interrelation between the lending rate and non-performing loans as a decision factor. The paper employed Augmented Dickey Fuller (ADF), Phillips Perron (PP), and Kwiatkowski–Phillips–Schmidt–Shin (KPSS) for stationarity tests, Autoregressive Distributed Lag (ARDL) Bound Test for cointegration and an ARDL model for the regression analyses using quarterly data. The results of the analyses showed a positive and consequential link connecting non-performing loans and lending rates, proving the existence of adverse selection in the Nigerian credit market in the short-run and long-run. Based on the results, the study recommends that the apex bank implement a price ceiling in the credit market. Banks and other financial institutions should properly define their lending rates given their cost of funds and other operational expenses. And hence, carefully select viable borrowers from the credit market that suit the bank’s credit policy rather than adjust the lending rate up to compensate for higher risk.

The Significance of Foreign Direct Investment Registered Projects and Employment Creation in the Sectors of Ghana’s Economy

The flow of foreign direct investment (FDI) into the Ghanaian economy has contributed significantly to the various sectors. This study seeks to assess the impact of registered investment (FDI and domestic) projects on employment generation in the agriculture, building & construction, manufacturing, and service sectors. The data for this study was obtained from the Ghana Investment Promotion Centre (GIPC) for the period 2001 to 2018. The Kwiatkowski-Phillips-Schmidt-Shin (KPSS) test showed a unit root existence in the time series. The regression results show no significant impact of registered investment projects on the agriculture and manufacturing sectors at a 5% significance level. Our findings also indicated that employment creation through registered investment projects has no effect on the manufacturing industry. The outcome also revealed that the service sector benefits more from FDI than the other sectors. It is recommended that the government boost these non-performing sectors with incentives to attract more investors.

The effect of natural resources and economic factors on energy transition: New evidence from China

Recently, energy transition is an essential element for global development and needs the attention of recent researchers and policymakers. Thus, the present research investigates the impact of natural resources (total natural resources rent and natural gas rent) and economic factors (energy import, economic growth, and population growth) on the energy transition in China. Secondary data were collected from world development indicators (WDI) from 1971 to 2019. The Augmented Dickey-Fuller (ADF) test, Phillips–Perron (PP) test, Kwiatkowski–Phillips–Schmidt–Shin (KPSS) and “zivot-andrews structural break unit root” test was also utilized to check for stationarity among the autoregressive distributed lag model (ARDL) along with the error correction model (ECM) were used to examine the relationships between constructs. The results found that natural resources (total natural resources rent and natural gas rent) and economic factors (energy import, economic growth, and population growth) have a positive association with energy transition in China. The study concluded that energy transition is the essential requirement due to high usage of natural resources and high economic development. These results are helpful for energy sector regulators when formulating the rules and regulations related to energy transition in the country.

The Causal Nexus Between Foreign Direct Investment and Economic Growth in Indonesia: An Autoregressive Distributed Lag Bounds Testing Approach

The nexus between foreign direct investment and economic growth has long been among the most debated issues in macroeconomics. Some studies find a positive link between the two factors, but others find no evidence. This current research fills the gap by analysing the causal nexus between foreign direct investment and economic growth in Indonesia for the period 1970-2018. Indonesia as a developing country is one of the largest recipients of FDI flow; hence the study on the impact of FDI on the economic growth is very much important. This current research employs a contemporary time-series procedure, involving several unit-root tests namely Augmented-Dickey-Fuller (ADF), Phillips-Perron (PP), Kwiatkowski-Phillips-Schmidt-Shin (KPSS), and Lee-Strazicich (LS), an Auto-Regressive-Distributed-Lag (ARDL) bounds-testing method for cointegration, and Granger causality test. The findings provide evidence of long-run and short-run causal direction from GDP to FDI. In contrast, FDI generates only a short-run relationship on GDP. The Granger causality test confirms the finding in ARDL that there is a unidirectional causality running from GDP to FDI.

A Random walk down the Dhaka Stock Exchange lane

Market efficiency has always been a matter of keen interest to the researchers of finance. Since the advancement of this concept, researchers are consistently investigating the market efficiency of different financial markets. Bangladesh, being one of the emerging economies, has also attracted the attention of many researchers. The researchers have investigated the realities regarding the market efficiency of both the stock exchanges of the country. Most of their investigations reveal that the Dhaka Stock Exchange (DSE) and the Chittagong Stock Exchange (CSE) are inefficient. This research, however, did not stop at revisiting market efficiency alone. Whether the return series follows a long-memory process, has also been tested. Besides, non-parametric tests have also been conducted to confirm the results of the parametric tests and vice versa. It generated a more reliable estimate of market efficiency for the period under study. Results of the Autoregressive Fractionally Integrated Moving Average (ARFIMA) model confirm that the return series does not follow a long memory process, and any shock in the system will eventually vanish. The findings of other tests (the run test, the Augmented Dickey-Fuller (ADF) test, the Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test, and the Kolmogorov-Smirnov (K-S) test) suggest that the return series of the DSE are time-series stationary, non-normal, and do not follow a random walk. Given these results, we must echo the prior researchers to conclude that the stock market of Bangladesh is not efficient for the period of 2015 to 2020. These findings add new knowledge to the existing knowledge pool about market efficiency and long memory of the stock market of Bangladesh.

A Dynamic Multivariate Causality Analysis of Energy–Growth Nexus Using ARDL Approach: A Malaysian Energy Policy Perspective

This study analyzes a dynamic long-run and short-run causal nexus between energy consumption and economic growth in the presence of capital, labor, and urbanization over the period 1971–2014, in Malaysia. The stationarity issue was tested using augmented Dickey–Fuller (ADF), Kwiatkowski–Phillips–Schmidt–Shin (KPSS), and Ng–Perron tests. However, a dynamic long-run co-integration relation between variables was checked through the ARDL technique. An unrestricted vector error correction model (MUVECM) was used to estimate the short-run and long-run dynamic relations between the parameters and the Engle–Granger method was used for causality analysis. Results of statistical analysis confirmed that all variables were found to be I (1) except variable labour was I(0) and none of the variables was I(2). Total energy consumption Granger caused GDP in one direction over the period 1992-2010 in the case of Croatia. However, labor and urbanization impacts were mixed. The Granger causality analysis confirmed mixed results in the short run and the long run. Moreover, estimated results confirmed a feedback hypothesis between income and capital was in the short term and the long run. The short-run and long-run causal effects of labor force on economic growth were confirmed. This study provides important insights to policymakers and energy economists. Prudent energy conservation policies and economically improved measures would be of great help. However, demand-side management-based policies would have no adverse effect on the economic performance of Malaysia.

Cointegration test for the long-run economic relationships of East Africa community: evidence from a meta-analysis

PurposeThe purpose of the paper is to test and analyze the equilibrium economic relationships of the East Africa Community (EAC).Design/methodology/approachTo attain the study's purpose the authors applied the Johansen cointegration test, including long-run structural modeling (LRSM), vector-error-correlation-model (VECM) and variance-decomposition (VDC).FindingsAt I(1), both Philips‐Peron (PP) and Kwiatkowski–Phillips–Schmidt–Shin (KPSS) tests show that the East Africa member states' economies are cointegrated. The result was further substantiated by the tests based on Johansen cointegration and VECM procedures, showing significant long-run and short-run economic relations. The result further reveals that despite some uncommon issues among member states such as Tanzania and Kenya, however, their economic relationships remain significant though it is negative. Moreover, the finding revealed positive and significant short-run economic relationships between Kenya, Burundi and Rwanda.Originality/valueThe paper applies the cointegration techniques in the context of EAC. The result is likely to be adding value to the policymaker and also to the existing literature on the subject. This may trigger policy implications and open new research direction within the region and out.

Lamb Wave Based Structural Damage Detection Using Stationarity Tests.

Lamb waves have been widely used for structural damage detection. However, practical applications of this technique are still limited. One of the main reasons is due to the complexity of Lamb wave propagation modes. Therefore, instead of directly analysing and interpreting Lamb wave propagation modes for information about health conditions of the structure, this study has proposed another approach that is based on statistical analyses of the stationarity of Lamb waves. The method is validated by using Lamb wave data from intact and damaged aluminium plates exposed to temperature variations. Four popular unit root testing methods, including Augmented Dickey–Fuller (ADF) test, Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test, Phillips–Perron (PP) test, and Leybourne–McCabe (LM) test, have been investigated and compared in order to understand and make statistical inference about the stationarity of Lamb wave data before and after hole damages are introduced to the aluminium plate. The separation between t-statistic features, obtained from the unit root tests on Lamb wave data, is used for damage detection. The results show that both ADF test and KPSS test can detect damage, while both PP and LM tests were not significant for identifying damage. Moreover, the ADF test was more stable with respect to temperature changes than the KPSS test. However, the KPSS test can detect damage better than the ADF test. Moreover, both KPSS and ADF tests can consistently detect damages in conditions where temperatures vary below 60 °C. However, their t-statistics fluctuate more (or less homogeneous) for temperatures higher than 65 °C. This suggests that both ADF and KPSS tests should be used together for Lamb wave based structural damage detection. The proposed stationarity-based approach is motivated by its simplicity and efficiency. Since the method is based on the concept of stationarity of a time series, it can find applications not only in Lamb wave based SHM but also in condition monitoring and fault diagnosis of industrial systems.

Performance of commercial and residential real estate investments in Ibadan property market, Nigeria

PurposeThis study examined the performance of commercial and residential real estate investments in the Ibadan property market to provide information for investment decisions.Design/methodology/approachThe study used a mixed research design (qualitative and quantitative). Data were obtained employing in-depth interviews with randomly selected sixteen estate surveyors and valuers practising in the Ibadan property market. Data for the study were analysed using the phenomenological thematic content analysis. Similarly, data on rental and capital values were translated to income, capital and holding period returns. The Kwiatkowski–Phillips–Schmidt–Shin (KPSS) and Philip–Perron (PP) models were used for unit root analysis. Ordinary least square (OLS) regression model was used to test for inflation-hedging characteristics, and the Granger causality tests were carried out to analyse the causal relationship between the variables.FindingsThe study revealed that the Ibadan property market is still immature. For the return components, the study found that the Ibadan property market provided mean holding period returns of 10.82%, 14.31 and 8.29% for office, shop and residential property types, respectively. The study also revealed that the selected property types are perverse hedges against inflation. Similarly, the study showed a unidirectional causal relationship between inflation and returns on the selected property types.Practical implicationsResults of this study revealed the peculiar nature of the Ibadan property market; findings from the survey can be used as a guide for investment decisions by foreign and domestic investors. Shrewd investors can take advantage of the high returns provided by the real estate assets in the Ibadan property market (by investing in the property market) to obtain high returns and expand their investment portfolio.Originality/valueThis study is the first to examine, in an eclectic and comparative context, the performance of commercial and residential properties in the Ibadan property market from the perspective of its market maturity level, returns profile, as well as its inflation-hedging characteristics. Findings from the study will equip both individual and institutional investors with valuable information for investment decisions.

The effect of the COVID-19 outbreak on hospitality and tourism stock returns in Thailand

ABSTRACT This study examines the volatility transmission effects between stock returns and the growth rate of total confirmed COVID-19 cases by using daily data of the hospitality and tourism industry taken from the Stock Exchange of Thailand (SET) index. Augmented Dicky–Fuller (ADF), Phillips–Perron (PP), Kwiatkowski–Phillips–Schmidt–Shin (KPSS), Elliott–Rothenberg–Stock (ERS) and Ng–Perron (NP) unit root tests were used to test, for both series are stationary. The BEKK-GARCH methodology was employed to formulate conditional variance-covariance equations. The results reveal that the pandemic interacts negatively with stock returns from the hospitality and tourism industry. Stock market returns are significantly negatively associated with daily growth in total confirmed COVID-19 cases.

Evaluation of temporal variability and stationarity of potential evapotranspiration in Peninsular Malaysia

Abstract Potential Evapotranspiration (PET) functions as an indicator to estimate the amount of water loss to the atmosphere. Over the years, global climate change has eventually led to a change of PET capacity and this has affected the agricultural sector and water resource management. The objective of this study was to determine the best PET estimation method as well as to carry out a trend analysis and stationarity test of PET in Peninsular Malaysia. The Mann–Kendall (MK) test and Sen's slope estimator were applied for the trend analysis while the Augmented Dickey–Fuller (ADF) test and Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test were applied for the stationarity test. The findings showed that Pulau Langkawi and Kuantan stations exhibited increasing trends while Bayan Lepas station exhibited decreasing trends for the daily, monthly, and annual PET time series. The daily, monthly, and annual PET time series at Bayan Lepas, Ipoh, Subang and Muadzam Shah stations were found to be stationary. Overall, the PET trend was found to be higher in the coastal regions and stationary in the mountainous region.

ATTENTION OF ECONOMIC GROWTH AND OIL PRICES: EVIDENCE FROM INDONESIA

Oil is a commodity that can cause turmoil for the global economy. This study attempts to examine the relationship between oil prices and economic growth together with the exchange rate and inflation rate in Indonesia. The time span covered by this series is from 2000 (Q1) to 2019 (Q4), providing 80 observations. Tests carried out in this study included unit root testing through Augmented Dickey-Fuller (ADF) testing, Phillips-Perron (PP) testing, Kwiatkowski-Phillips-Schmidt-Shin (KPSS) testing, Johansen and Juselius cointegration test, Granger-based causality test. Vector Error Correction Model (VECM) to determine long-term and short-term relationships, and Variance Decomposition and Impulse Response Function to investigate relationships outside the sample. The empirical findings show that there is a relationship between variables, oil prices not only affect economic growth but also have an impact on the exchange rate and inflation rate. Furthermore, the results of the short-run Granger causality for the tested variables indicate a unidirectional causality that runs from all independent variables, namely oil prices, exchange rates, and the rate of inflation on GDP. In addition, there is a causal relationship between GDP and other determinants outside the sample. The addition of time-frames and variables can add to the variance of the sustainability of these findings in the future.Keywords: Oil price shocks, Economic growth, Panel data, Regression method, Indonesia.JEL Classification: D24, A1, C23DOI: https://doi.org/10.32479/ijeep.11538

Udział kobiet w rynku pracy w Arabii Saudyjskiej i jego determinanty

Saudi Arabia's Vision 2030 recognized female labor force participation as an important component for economic growth. This study investigates the relationship between female labor force participation rate, female tertiary school enrolment, female life expectancy and per capita income measured quarterly between 1991 and 2017. The study employs traditional unit root tests of Augmented Dickey-Fuller (ADF), Phillips-Perron (PP) and Kwiatkowski–Phillips–Schmidt–Shin (KPSS) complemented by Zivot and Andrews (ZA) test. Furthermore, for robustness check, combined cointegration test as prescribed by Bayer and Hanck (2013) and Pesaran ARDL bound tests were performed. Toda-Yamamoto causality test examined the causality flow among the variables. The result posits all independent variables have positive significant effect on female labor force participation rate within Saudi Arabia; rendering a policy recommendation: higher female labor participation can be achieved through investment in female education, health sector and achieving economic growth.

Empirical Implications of Decentralization Dimensions and the Role of Political Institutions in the Economic Growth of Pakistan

Decentralization is the fundamental policy variable used to enhance the allocative efficiency through public spending / tax priorities, subject to the local demand. The current study evaluates the impact of the various dimensions of decentralization on the economic growth of Pakistan for the years 1972-2018. Ng-Perron tests and Kwiatkowski-Phillips-Schmidt-Shin (KPSS) were applied to fix the unit root problem in the time series data. To find the cointegration among decentralization, the role of institutions, and economic growth the Autoregressive Distributed Lag Approach (ARDL) was used. The outcomes suggested that tax decentralization is a growth promoting policy. On the contrary, administrative and political decentralization negatively affect the economic growth. The analysis shows that political freedom also has a growth retarding impact on the economy. The current study is useful regarding the policy implications of the process of decentralization.

Laparoscopic Pectopexy-CUSUM Learning Curve and Perioperative Complications Analysis.

The study aimed to examine the learning curve and perioperative complications for laparoscopic pectopexy (LP). A total of 60 women with stage II–IV apical prolapse who underwent LP were dichotomized into groups: LSH(+) with concomitant laparoscopic supracervical hysterectomy (LSH), LSH(−) after previous supracervical/total hysterectomy. Operative time, estimated blood loss and hospitalization length were evaluated with cumulative sum (CUSUM) analysis and the Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test, separately for two surgeons (A and B). Intraoperative and perioperative complications according to the Clavien–Dindo (C–D) classification were analyzed. Mean operative time, change in hemoglobin level, and postoperative hospital stay were 143.5 ± 23.1 min—1.5 ± 0.5g/dL and 2.5 ± 0.9 days, respectively. LSH during pectopexy was associated with longer operative time (p = 0.01) but not with higher intraoperative bleeding or prolonged hospital stay. Severe complications rate was low (1.7%) with one bowel injury in LSH(−) (C–D grade IIIb). No C–D grade II, IV and V complications were found. Conversion to open pectopexy, return to the operating room or blood transfusion were not required. The KPSS test showed that a steady operative time for Surgeon A was achieved after 28 procedures. A proficiency for laparoscopic pectopexy based on CUSUM analysis was observed after 38–40 procedures.

Enerji Yoğunluğu ve İklim Değişikliği: Türkiye İçin Yakınsama Analizi

The aim of this study is to analyze Turkey’s convergence to the European Union (EU) in terms of energy intensity. In the study, first of all the relationship between energy intensity and climate change has been examined. Afterwards, Turkey’s convergence to EU countries and EU average has been analyzed using the annual energy intensity data including the years 1990-2018. In the analysis, Augmented Dickey-Fuller (ADF), Kwiatkowski-Phillips-Schmidt-Shin (KPSS), PhilipsPerron (PP), NG-Perron and Fourier ADF unit root tests were used. According to the findings obtained, it was concluded that Turkey converges to Italy, Spain, and Portugal with regards to energy intensity, on the other hand doesn’t converge to Germany, United Kingdom, Belgium, France, Holland, Sweden, Czechia, Poland, Romania, and EU average.

Global Mean Sea Level Nexus Climate Change: A Dynamic Cointegration and Causality Analyses

Nowadays, the impact of climate change on the global mean sea level variations is becoming an important issue to the researchers and policy makers as a general concern about environmental degradation is making their way into global policy agenda. That is why, in this paper the principal purpose has been made to investigate the dynamic cointegration and causality relationships between global mean sea level (GMSL) and its determinants. Also another purpose has been made to examine empirically the short-run and long-run effects of climate change, carbon dioxide emissions, energy consumption, trade openness and urbanization on global mean sea level based on the time series data from 1970-2019. From the Augmented Dickey-Fuller (ADF), Phillips-Perron (PP) and Kwiatkowski-Phillips-Schmidt-Shin (KPSS) tests results it is found that all the variables are integrated of order one i.e. I(1). From the bounds test approach, it is found that there exits only one cointegration relationship when GMSL is the dependent variable. From the Granger causality test results of VEC model, it is found that the short-run unidirectional causalities are running from carbon dioxide emissions and energy consumption to global mean sea level, from energy consumption and trade openness to carbon dioxide emissions and from trade openness to energy consumption. It has also been found that the error correction term is statistically significant at any significance level when global mean sea level is treated as endogenous variable indicating that there exists a long-run relationship among the variables in the form of Equation (1). It has also been found that in the short-run the variables temperature, carbon dioxide emissions, and urbanization have significant positive effects while energy consumption and trade openness have significant negative effects on global mean sea level at any significance level. The coefficient of ECM (-1) is statistically significant at any significance level, indicates that speed of adjustment for short-run to research in the long-run equilibrium is statistically significant and within the first year, when global mean sea level is above or below its equilibrium level, it adjusts 66.52%. It has also been found that in the long-run the variables temperature, carbon dioxide emissions, and urbanization have significant positive effects on global mean sea level at any significance level but the variable energy consumption has significant negative effects at 5% significance level. It is also found that over time higher temperature, and carbon dioxide emissions will increase global mean sea level rapidly. The CUSUM and CUSUMSQ tests results support that the VEC model is stable and can be applied for policy formulation and decision making purposes.