Nonlinear Linkage Research Articles

Association between life's essential 8 and Parkinson's disease: a case–control study

ObjectivesLife's essential 8 (LE8) is an emerging approach for accessing and quantifying cardiovascular health (CVH), but the effect on Parkinson's disease (PD) is still unclear. This study aimed to elucidate the association between LE8 metrics and PD in the US adults.MethodsData of 26,975 participants were extracted from the last 7 National Health and Nutrition Examination Survey (NHANES) cycles (2005–2018). The LE8 metrics were calculated according to the American Heart Association criterion, and participants were divided into 3 groups using tertile range. Multivariate logistic regression models were constructed to explore the association between LE8 metrics and PD. Sensitivity analysis was conducted to verify robustness. A nonlinear linkage was evaluated via restricted cubic spline (RCS). The stability of this effect was validated by subgroup analysis and interaction test.ResultsA total of 26,975 eligible participants (including 271 PD cases and 26,704 non-PD cases) were included in this study. The multivariate logistic regression models revealed a reverse association of continuous LE8 metrics with PD with ORs of 0.97 (unadjusted model [95% CI: 0.96–0.98, P < 0.01], partially adjusted model [95% CI: 0.97–0.98, P < 0.01], fully adjusted model [95% CI: 0.95–0.98, P < 0.01]). Compared to those of low group, the ORs for high group were 0.37 (95% CI: 0.27–0.50, P < 0.01) in unadjusted model, 0.51 (95% CI: 0.36–0.72, P < 0.01) in partially adjusted model, and 0.51 (95% CI: 0.32–0.81, P < 0.01) in fully adjusted model. The sensitivity analysis ensured the robustness of the observed LE8-PD association. A nonlinear relationship (Pnonlinearity < 0.01) was observed via RCS analysis. The subgroup analysis showed that participants'gender might impact the strength of LE8 metrics-PD association (Pinteraction = 0.029).ConclusionsCVH, as delineated by LE8 metrics, was reversely associated with PD in the dose–response pattern, more pronounced in female compared to male. These findings highlight the potential of the LE8 metrics to guide targeted strategies for addressing gender-based CVH disparities, offering beneficial insights for the tertiary prevention of PD.

COVID-19 pandemic and linkage between stock markets in Middle Eastern countries

PurposeThe purpose of this study is to evaluate the linkage between stock markets in Middle Eastern countries before and during the COVID-19 pandemic by using daily and monthly data sets for the period from 2011 to 2021.Design/methodology/approachThe multivariate BEKK-GARCH model was computed to evaluate the existence of non-linear linkage among Middle Eastern stock markets. A correlation approach was used in this study to determine the type of linear connectivity between Middle Eastern stock markets. The study used monthly and daily data sets covering the years 2011 to 2021 to investigate the linkage between stock returns and the volatility spillover between the stock markets in Palestine, Jordan, Syria and Lebanon, both before and during COVID-19. To understand the types of relationships between markets before and during COVID-19, the daily data set was split into two periods.FindingsResults from the pre-COVID-19 suggest that the Syria stock market is not related to any stock market in the Middle East markets; the Palestine and Lebanon stock markets exhibit a weak relationship, but Jordan and Palestine stock markets are strongly linked. Conversely, results from COVID-19 evince a very strong bidirectional volatility spillover between Middle East stock markets. Overall, the results indicate the existence of increased linkage during the COVID-19.Research limitations/implicationsThe data collection on a daily and monthly basis, both before and during COVID-19, presents certain limitations for the paper. Another limitation is that the data cannot be generalized to all other Middle Eastern countries; rather, the conclusions drawn can only be applied to these four countries. This is especially true if the scholars collected most of the necessary data but were unable to obtain certain data for various reasons.Practical implicationsThese findings have implications for risk management, market regulation and the growth of local stock markets. Facilitating the growth of smaller, more specialized markets to improve integration with other Middle Eastern markets is one of the goals of the domestic stock market development policy. To ensure financial stability, Middle Eastern stock market linking policies should consider spillover risk and take steps to minimize it. Enhancing the range of investment opportunities accessible to shareholders and functioning as confidential risk-sharing mechanisms to facilitate improved risk management in Middle Eastern stock markets will not only significantly influence the mobilization of private capital to promote investment and local economic growth but also lay groundwork for integrated market platforms.Originality/valueThis paper adds to the body of literature by demonstrating the nature of the connections between these small markets and the larger markets in the Middle East region. Information from the smaller markets provides institutional insights that enhance the body of existing research, guide the formulation of evidence-based policies and advance financial literacy in these markets. This study contributes by comparing data from different stock markets to better understand the type and strength of the link and relationship between Middle Eastern stock markets, as well as any underlying or reinforcing factors that might have contributed to the relationship and the specific types of links that these markets shared prior and during COVID-19.

Non-linear association of triglyceride-glucose index with cardiovascular and all-cause mortality in T2DM patients with diabetic kidney disease: NHANES 2001–2018 retrospective cohort study

BackgroundThe triglyceride glucose (TyG) index is a cutting-edge and highly effective marker of insulin resistance, a crucial factor in the development and exacerbation of diabetic kidney disease (DKD). To date, there has been limited research on how the triglyceride-glucose (TyG) index affects the outlook for patients suffering from DKD.MethodsIn this multicenter retrospective cohort study, the analysis recruited 2,203 DKD patients from the National Health and Nutrition Examination Survey (NHANES) dataset, which covers the US from 2001 to 2018. The research applied a Cox proportional hazards model with multiple variables to investigate the association of the TyG index with mortality outcomes. Restricted cubic splines (RCS) and methods for analyzing threshold effects were employed to identify possible non-linear relationships.ResultsOver nearly 19 years of follow-up, this study captured data on 753 all-cause and 231 cardiovascular disease-specific fatalities. Sophisticated statistical methods, including RCS and smoothing curve adjustments via penalized splines, helped identify distinctive patterns: The baseline TyG index was observed to have a U-shaped pattern related to overall mortality and an L-shape with cardiovascular diseases(CVD) mortality among individuals with DKD. Notably, TyG index below 9.15 for overall mortality and 9.27 for CVD mortality were linked to reduced death rates (HR = 0.65, 95% CI = 0.52–0.82 for all-cause; HR = 0.58, 95% CI = 0.43–0.83 for CVD). On the other hand, TyG index exceeding these benchmarks (greater than 9.15 for all-cause and 9.27 for CVD) correlated with increased all-cause mortality risks (HR = 1.21, 95% CI = 1.02–1.43) and showed a non-significant change in CVD mortality risks (HR = 1.07, 95% CI = 0.83–1.38).ConclusionsThis study emphasizes the non-linear linkage involving the TyG index and death rates due to CVD and other factors in patients with DKD, demonstrating its effectiveness in estimating potential adverse events within this demographic.

Venture capital, internationalization strategy and corporate innovation

PurposeThe purpose of this study is to explore the influence of venture capital participation on corporate innovation and to assess how internationalization strategies (including both the internationalization scope and speed) in mediating serve as intermediaries in the relationship between venture capital and corporate innovation.Design/methodology/approachUsing hierarchical regression analysis, this research tests the hypothesized framework using survey data collected from 442 high-tech enterprises listed on the A-share markets in Shanghai and Shenzhen, China, spanning from 2010 to 2019.FindingsThe study reveals a non-linear (U-shaped) correlation between venture capital investment and innovation. This non-linear linkage is facilitated through the execution of enterprises’ strategies for international expansion. The primary finding suggests that venture capital participation positively influences the rapidity and extent of internationalization. Additionally, a U-shaped relationship is observed between corporate innovation and both the speed and scope of internationalization.Originality/valueThis document contributes insights into the micro-level mechanisms that explain the effects of venture capital and internationalization strategy on corporate innovation. The results offer multinational corporations practical guidance for executing their internationalization strategies effectively and fostering innovation.

Exploring Nonlinear Linkage between Corporate Financialization and Innovative Efficiency: Identification and Governance of Excessive Financialization*

AbstractThis paper investigates the underlying causes of the nonlinear link between financial asset holdings and innovative efficiency. It identifies an inverted U‐shaped pattern linking corporate financialization to innovation, with financing restrictions, agency costs, and business risk serving as some of the relationship's partial mediating factors. By categorizing financial assets into short‐term monetary and long‐term nonmonetary types, it reveals heterogeneous effects on innovative efficiency, suggesting that the impact is not solely crowding out or a pulling effect but varies based on asset type and proportion. Additionally, it argues for continual adjustment of proper corporate financialization levels based on firm‐specific factors and changing external conditions. Notably, excessive financialization appears less prevalent among Chinese firms, with internal governance and external environmental enhancements recommended to optimize financialization for innovation.

Revisiting the interest rate-investment nexus in India: fresh perspective from non-parametric analysis

PurposeIt is generally believed that business spending on capital expenditure tends to decrease as interest rates rise, and vice versa, this is not always the case. The previous literature produces inconclusive results vis-à-vis the interest rate and investment nexus. This study analyzes the responsiveness of investment to changes in high and low levels of interest rates in India through a quantile-based, non-parametric method utilizing annual data from 1980 to 2022.Design/methodology/approachThis study uses Quantile-on-quantile (QQ) technique proposed by Sim and Zhou (2015) to examine the impact of interest rate quantiles on quantiles of investment. In addition, long-term association and the direction of causality are estimated through the Cho et al. (2015) test of quantile cointegration and the Jeong et al. (2012) Granger causality in quantile (GCQ) test, respectively.FindingsThe empirical evidence validates that the linkage between investments and interest rate is not consistently negative and varies from quantile to quantile. The study finds a negative impact at median quantiles and a positive impact at extreme higher quantiles. Conversely, the impact at lower quantiles is negligible, which is also observed from quantile cointegration, indicating the presence of a statistically significant association above the median quantiles. Additionally, the study finds one interesting finding that there exists unidirectional causality from investment to interest rates in India rather than other way around.Research limitations/implicationsThe study provides significant implications for policymakers as it suggests that during extreme economic conditions, the effectiveness of traditional monetary policy tools to boost capital formation is restricted. Policymakers may consider alternative measures to stimulate investment during these time periods. The study additionally posits that the neoclassical theory of investment may not be readily applicable in emerging economies in its unaltered state, mostly due to the lack of well-developed financial markets.Originality/valueThere is a limited literature available on non-linear linkage between interest rates and investment. The present study adds to the existing knowledge by investigating how investment responds differently to fluctuations in interest rates, while incorporating the complete distribution of both the variables.

Multi-Point Deformation Prediction Model for Concrete Dams Based on Spatial Feature Vector

Deformation can effectively reflect the structural state of concrete dams and, thus, establishing na accurate concrete dam deformation prediction model is important for dam health monitoring and early warning strategies. To address the problem that the spatial coordinates introduced in the traditional multi-point deformation prediction model of dams not being able to accurately and efficiently reflect the spatial correlation of multiple-measuring points, a 2D-1D-CNN model is proposed which expresses the spatial correlation between each measuring point through spatial feature vectors, replacing the spatial coordinates in the traditional multi-point model. First, the spatial feature vector is extracted from the historical spatio-temporal panel series of deformation values of measuring points via a Two-Dimensional Convolutional Neural Network (2D-CNN); second, the vector is combined with the environmental impact factor of dam deformation to form the final input factor of fused spatial features; and, thirdly, this vector is combined with the environmental impact factors of dam deformation to form the final input factor of fused spatial features, and the non-linear linkage between the factors and the measured displacement values is constructed by the efficient feature processing capability of a One-Dimensional Convolutional Neural Network (1D-CNN) to obtain the prediction results. Finally, the actual monitoring data of a concrete dam in China are used as an example to verify the validity of the model. The results show that the proposed model outperforms the other models in most cases, respectively, which verifies the effectiveness of the proposed model in this paper.

Linear and non-linear linkage between human capital and foreign direct investment inflows into APEC countries: an evidence from panel data

Linear and non-linear linkage between human capital and foreign direct investment inflows into APEC countries: an evidence from panel data

Nexus between financial development and carbon emission in Bangladesh: Evidence from ARLD and NARD

The motivation of the study is to assess the impact of financial development, trade openness and foreign direct investment on environmental sustainability in Bangladesh for the period 1990-2019. The results of combined cointegration and Makki cointegration revealed long-run cointegration between explained and explanatory variables, moreover the cointegration test under symmetry and asymmetry established the similar line of evidences. Referring to the coefficients of FD, TO and FDI, it is apparat that population haven hypothesis has revealed, suggesting the environmental degradation has expedited due to FD, TO and FDI in Bangladesh in the long and short run. Additionally, the asymmetric assessment revealed nonlinear linkage between explained and explanatory variables in the long-run and short-run.

Environmental pollution and economic growth: Evidence of SO2 emissions and GDP in China.

This study explores the inherent linkage mechanism between environmental pollution and economic growth using a non-linear MS (M)-VAR (p) model. The results indicate that, first, the growth rates of China's gross domestic product (GDP) and SO2 emissions are in a state of significant inertia. Second, when the system was in a medium-growth regime, the growth rates of SO2 emissions and GDP had a positive correlation, characterized by lower probability and weaker durability. Third, when the system was in a high- or low-growth regime, their growth rates were negatively correlated, characterized by higher probability and stronger durability. Overall, economic growth increases environmental pollution emissions, which intensifies as well as inhibits economic growth. The correlation and sustainability of SO2 emissions and GDP are closely related to the regional status of the entire system. This study is helpful in analyzing the reasons for the nonlinear linkage mechanism between environmental pollution and economic growth.

Use of interpretable machine learning to identify the factors influencing the nonlinear linkage between land use and river water quality in the Chesapeake Bay watershed

Use of interpretable machine learning to identify the factors influencing the nonlinear linkage between land use and river water quality in the Chesapeake Bay watershed

Relationship between Real Exchange Rate and Consumption in Nigeria: A Nonlinear Approach

This study analyses the relationship between real exchange rate and domestic consumption in Nigeria using the Smooth Transition Autoregressive (STAR) model from 1981Q1 to 2019Q4. Findings show that domestic consumption determines the regime shift in real exchange rate, suggesting a nonlinear linkage with clearly distinct regimes. The lagged exchange rate is shown to have a significant linear effect on the current exchange rate. On the other hand, current foreign consumption is positive but has no significant impact on the exchange rate in the linear part of the model. In the nonlinear part of the model, evidence of a significant negative relationship between real exchange rate and domestic consumption is found, thus, supporting the proposition of the standard international business cycle model. In addition, the study finds evidence of bi-directional nonlinear granger causality between real exchange rate and domestic consumption. The study concludes that the relationship between real exchange rate and domestic consumption is nonlinear and that fiscal and monetary authorities should aim at policies that would stimulate domestic consumption below the threshold level necessary to keep the exchange rate stable.

Bond risk’s role in the equity risk-return tradeoff

Bond risk’s role in the equity risk-return tradeoff

Correlation Analysis of Surplus Labor Transfer and Economic Growth Based on STR Model

For a long time, the research on the relationship between economic growth and the transfer of surplus labor has been the focus and hot issue of all kinds of people. As a model that can describe the nonlinear transformation between different states of variables in detail, the STR model is the Frontier and hot topic of nonlinear time series analysis. In recent years, it has been successfully applied in the fields of economy, finance, capital market, macro policy simulation, and so on. The STR model can well describe the nonlinear and nonequivalent linkage effect between economic growth and surplus labor and has significance in both practice and theory. By constructing an STR model of four variables, including the added value of rural labor transfer and the real added value of each industry, this paper conducts an empirical analysis on the extremely dynamic interaction between the transfer of rural surplus labor and various industries in China. There is an interactive effect of economic growth. The results of the study show that the relationship between human capital and economic growth in China presents a nonlinear characteristic of periodic changes, and frequently switches between linear and nonlinear relationships.

Linear and nonlinear linkage of conditional stochastic volatility of interbank interest rates: Empirical evidence of the BRICS countries

The purpose of this article is to detect a possible linear and nonlinear causal relationship between the conditional stochastic volatility of log return of interbank interest rates for the BRICS countries in the period from January 2015 to October 2018. To extract the volatility of the analyzed time series, we use a stochastic volatility model with moving average innovations. To test a causal relationship between the estimated stochastic volatilities, two steps are applied. First, we used the Granger causality test and a vector autoregressive model (VAR). Secondly, we applied the nonlinear Granger causality test to the raw data to explore a new nonlinear causal relationship between stochastic volatility time series, and also applied it to the residual of the VAR model to confirm the causality detected in the first step. This study demonstrates the existence of some unidirectional/bidirectional linear/nonlinear causal relationships between the studied stochastic volatility time series.

Exploring nonlinear linkage between profitability and leverage: US multinational versus domestic corporations

AbstractThis study examines the impact of profitability on the capital structure decision of US multinational and domestic corporations. The findings reveal that the relationship between multinational corporations’ (MNCs') profitability and their leverage ratios is U‐shaped and nonlinear, while this nonlinear relation does not exist for domestic firms (DCs). This nonlinear relationship indicates that the effect of profitability on multinational corporations' leverage depends on the levels of their profitability. Consistent with the dominance of the pecking order theory, lower‐profitability MNCs have a tax shield advantage that does not outweigh the information asymmetry costs of debt financing. Conversely, higher‐profitability MNCs have a tax shield advantage that outweighs the information asymmetry costs of debt financing. The findings are robust after using two different classifications for multinational firms, including foreign tax and foreign sales; after applying an alternative methodology and during different time horizons.

Simulation and test of a very efficient friction brake actuator with a statically balanced spring mechanism

Current automotive brake systems (pneumatic/hydraulic) are based on a split design: a central unit providing pressure and brake calipers transforming this pressure into clamping forces. Existing electromechanical brake calipers work without a central unit; but despite their simplicity they are not yet used. One major reason is the need of high forces and high electrical power for loading brake pads and calipers during braking. A possible solution is the application of a statically balanced spring mechanism; it stores elastic energy in a preloaded reversible spring mechanism integrated in the caliper. Using a nonlinear linkage mechanism, the stored energy transfers back and forth to and from the elastic parts of the brake caliper. Consequently, the additional power needed for applying and releasing the brake reduces significantly. The article analyzes the basic feasibility of such an actuator based on a double slider crank mechanism, which is determined for an application in a typical automotive disk brake caliper with high clamping forces of 20 kN. Experimental results from a demonstrator under real friction and stiffness conditions are presented and analyzed based on a theoretical model. The results prove the benefits of reducing driving power and also reveal critical points of the design.

The Nonlinear Linkage Between Earnings Homogamy and Earnings Inequality Among Married Couples.

More married couples today consist of two high-earning or two low-earning partners (i.e., earnings homogamy), which leads to greater earnings inequality in married-couple families. Surprisingly few studies have examined this relationship by earnings level, leaving open the question of whether the increase in earnings homogamy at each level of earnings contributes equally to between-couple earnings inequality. I address this question using data on urban China during 1988-2013. Changes in earnings homogamy account for 6% to 11% of the increase in between-couple inequality, but importantly, decomposition reveals that 57% to 68% of the overall impact is driven by the growing earnings homogamy among the top 20% of husbands and their wives. I reach the same finding by replicating the analyses using data from the United States. Two explanations account for this finding: (1) earnings homogamy has increased more among high earners; and (2) all else being equal, increases among high earners are mechanically more influential in shaping the level of between-couple inequality. These findings have important theoretical and policy implications.

Oil volatility index and Chinese stock markets during financial crisis: a time-varying perspective

PurposeThis study aims to examine the interconnection among the oil volatility index (OVX) and the Chinese stock markets (CSM) during the financial crisis over the period June 1, 2007 to June 26, 2012.Design/methodology/approachApplying the time-varying Granger causality test, this paper conducts an exhaustive analysis of the OVX and the CSMs during the financial crisis. In particular, the financial crisis is classified in three stages, namely, the US subprime crisis, the global financial crisis and the sovereign debt crisis.FindingsBriefly, the findings indicate almost a neutral relationship between the OVX and the CSMs during the entire financial crisis, the US subprime crisis and the global financial crisis. Finally, this paper has found a positive relationship between the OVX and the CSMs during the sovereign debt crisis.Practical implicationsThis outcome clearly suggests that Chinese investors have to disregard uncertain information. In addition, policymakers can ameliorate the willingness of market investors in the CSM and further deepen the market-oriented reform of China’s domestic oil prices.Originality/valueThe innovative combination of these two strands, the OVX and the three stages of the financial crisis, is empirically examined in the study and this paper finds a non-linear linkage between the OVX and CSMs.

Cash holdings: Do they boost or hurt firms’ performance? Evidence from listed non-financial firms in Saudi Arabia

Purpose The purpose of this paper is to study the relationship between corporate cash holdings and financial performance, both linearly and non-linearly, for listed non-financial firms in Saudi Arabia. Design/methodology/approach The data include all listed firms in Saudi Arabia’s primary stock market, excluding banks and insurance companies, over 2005–2016. The source for all data is the Osiris database. In evaluating the association between cash holdings and financial performance, static (i.e. pooled ordinary least squares) and dynamic (i.e. system generalized method of moments) specifications were implemented. Further, to confirm the non-linear linkage between cash reserves and financial performance, a U test was used. Findings The findings show that cash holdings play a significant role in firms’ performance; specifically, this relationship is non-linear, exhibiting an inverse U shape, driven by levels of cash reserves. This non-linear relationship verifies the tenets of the trade-off theory of optimum cash level based on the benefits and costs of holding cash. Research limitations/implications It is recommended that future studies investigate corporate liquidity and performance among Shariah-compliant firms and their conventional counterparts. Practical implications The findings of this study provide useful insights for managers and policymakers on efficient levels of corporate liquidity management. Social implications This paper provides further insights for investors on the role of corporate cash holding levels in firm performance. Originality/value To the best of the author’s knowledge, this paper is among the first to explore a non-linear relationship between cash holdings and firms’ performance using accounting measures.