Break Tests Research Articles

Price Dynamics and Integration in India’s Staple Food Commodities—Evidence from Wholesale and Retail Rice and Wheat Markets

Uncertain price movement in staple food commodities puts agrarian economies at risk if not monitored and managed consistently. Hence, an attempt has been made to analyze the price behavior and integration across major wholesale and retail markets for rice and wheat in India. Monthly data (July 2000 to June 2022) on prices viz. wholesale and retail were sourced from the Food and Agriculture Organization and analyzed using growth rate, instability index, seasonal price index, Bai-Perron’s test for structural breaks, Johansen’s test on cointegration, Granger causality test, and impulse response function. Findings indicated strong evidence of price dynamics in the selected markets in terms of spatial and temporal variation, clear-cut seasonality linking to production, and price divergence between wholesale and retail markets. Johansen’s test indicated a strong cointegration between wholesale and retail prices after accounting for structural breaks, exhibiting unidirectional-, bidirectional- and no causality. Impulse response analysis revealed that the selected wheat and rice markets are efficient in terms of ‘price discovery’ which takes place initially in the wholesale market, and is then transmitted to the retail market. The study advocates decision-making information to the producers, traders, and consumers who are interested in taking advantage of the price movement. It is concluded that strengthening the market intelligence and reducing the distortion in markets will improve the existing overall performance.

Interrogating the environmental accountability of foreign oil and gas companies in Basra, Iraq: a stakeholder theory perspective

PurposeThis paper aims to interrogate the accountabilities of the foreign companies which have directly invested in the Iraqi oil and gas industry.Design/methodology/approachUsing both qualitative and quantitative methodologies, the authors first map the stakeholder accountabilities (qualitative) of foreign oil and gas companies and second, the authors seek to demonstrate quantitatively – through structural break tests and publicly available sustainability reports – whether these companies have accounted for their environmental and social impacts both to Iraqi people and to the global community.FindingsThe authors find that the Western democratic values embedded in stakeholder theory, in terms of sustainability, do not hold the same meaning in cultural contexts where conceptions and application of Western democratic values are deeply problematic. This paper identifies a crucial problem in the global oil supply chain and problematises the application of traditional theoretical approaches in the context of the Iraqi oil and gas industry.Practical implicationsImplications of this study include the refocus of attention onto the local and global environmental impacts of the Iraqi oil and gas industry by foreign direct investments. Such a refocus highlights the reasons and ways that decision makers should accommodate these less salient stakeholders.Originality/valueThe primary contribution is the critique of the lack of environmental accountability of foreign direct investment companies in the Iraqi oil and gas industry. The authors also make theoretical and methodological contributions via the problematisation of the cultural bias inherent in traditional stakeholder theories, and by introducing a quantitative method to evaluate the accountabilities of companies.

Forecasting Stock Prices on the Basis of Technical Analysis in the Industrial Sectors of the UK Stock Market

This study aims to evaluate, critically and rigorously the weak-form market efficiency and forecasting power of technical analysis in different industries in the London Stock Exchange. Weekly data were collected from the FTSE-all share index, FTSE-350 general industrial index and twenty companies of four different industries, for the period between 1997 and 2017. Bai-Perron’s multiple breaks test was applied to diagnose plain data period for the purpose of forecasting. The statistical inference was made from the application of the runs test, variance ratio tests, Ljung-Box’s test and ADF-unit root test that the market is not weak-form efficient and stock prices are predictable. This study extends the current literature by considering the existence of weak-form inefficiency in different industrial sectors. The findings do not support for weak-form efficiency over the periods tested from the application of the ARIMA and GARCH (1, 1) models and double and triple exponential smoothing techniques

Bootstrapping tests for breaks in mean or variance based on U-statistics

Bootstrapping tests are implemented for the tests U by Schmidt [Detecting changes in the trend function of heteroscedastic time series; 2021. Preprint: arXiv:2108.09206 [math.ST]] for mean break and Schmidt et al. [An asymptotic test for constancy of the variance under short-range dependence. Ann Stat. 2021;49:3460–3481.] for variance break based on U-statistics. The tests U have good powers against epidemic breaks that are common in practice. The test U for variance break is proved to have the nice property of consistency against a general class of alternatives. However, the tests U have non-ignorable finite sample size distortion under serial correlation and/or conditional heteroscedasticity. Our implementation based on autoregressive residual bootstrapping and moving block bootstrapping are shown to remedy the size distortion problems of U for mean break and for variance break, respectively, in a Monte-Carlo experiment. The experiment also demonstrates the power advantages of bootstrapping tests over the original tests and other standard break tests against epidemic breaks, which, however, are accompanied by disadvantages against simple single breaks. The proposed bootstrapping tests are well illustrated by break analyses of means and variances of the log-return and realized the volatility of the US S&P 500.

Carbon Pricing in Current Global Institutional Changes

Global institutional changes (GICs), having influenced energy prices, led to a steady upward trend in carbon prices on the EU ETS. The aim of the article is to assess the changes in the relationship between carbon prices and energy prices under GICs. The Bai–Perron tests for structural breaks identified two dates as the breakpoint, 21 April 2016 and 21 September 2020. We test the hypothesis that powerful external factors (GIC) are changing the trend pattern of the carbon price time series. New pricing rules of the carbon price are being formed after the breakpoint. We use daily observations from 4 January 2010 to 1 September 2022. We use GARCH models with multiple stationary time series to discover a relationship energy price with the carbon price before and after the break points. We found that three models for two breakpoints better describe the relationship between carbon prices and energy prices than two models for one breakpoint, much less one model for the entire period. We find that the carbon price depends on energy prices, especially on the price of oil, in a statistically significant way, but the gas price is not statistically significant after 21 September 2020.

A new test for common breaks in heterogeneous panel data models

A new test is proposed to detect whether break points are common in heterogeneous panel data models where the time series dimension T could be large relative to cross-section dimension N. The error process is assumed to be cross-sectionally independent. The test is based on the cumulative sum (CUSUM) of ordinary least squares (OLS) residuals. The asymptotic distribution of the detecting statistic is derived under the null hypothesis, while the test is shown to be consistent under the alternative. Monte Carlo simulations and an empirical example show good performance of the test.

Economic Analysis of Iran’s Health System Transformation Plan Using the Structural Break Tests

Background and Objectives: Health system transformation plan (HSTP) of Iran, with three main goals of financial protection of patients, justice in access to health services, and improving the quality of services was implemented since 2014 which has had some achievements and challenges. Considering the large amount of financial resources used in this plan and the limitation of resources in Iran, this study aims to examine the performance of this plan in improving some health-related and financial indicators. Methods: Econometric tools were used in this study. The data of health-related and financial indicators related to the performance of HSTP from 2004 to 2019 were first collected. Then, using the ordinary and generalized least squares estimation methods, the effect of the transformation of HSTP on the selected indicators was examined. Finally, by using the structural break tests of Perron, Zivot-Andrews and Lee-Strazicich, the success of the HSTP in causing positive changes in the indicators and creating structural breaks was examined. Results: According to the ordinary and generalized least squares regression models, the coefficients of all indicators was significant and the positive effect of the costs of HSTP on the improvement of these indicators were confirmed. The greatest effect was reported on the out-of-pocket payment rate with a coefficient of 0.7 and the lowest effect was on the total death rate with a coefficient of -0.006. According to the results of the structural break tests, all indicators had recorded structural breaks before implementing the plan, while only six indicators showed structural breaks after the implementation. Conclusion:The HSTP was effective in improving the selected indicators at the beginning. All indicators showed structural break points before implementation of the HSTP, due to their reduction at the related time points, which emphasized the necessity of implementing the HSTP; however, after implementation, no positive structural break points are observed to indicate a considerable improvement in the indicators.

Two theories of endogenous money: an empirical study of Korea

This study tests Korea’s two endogenous money supply channels: the accommodationist and structuralist channels. The main analytic tools are the Fully Modified OLS, Maki’s structural break test, Error Correction Model, and Impulse Response Function (IRF) analysis. The primary purpose of this study is to propose analytical methods to compare the two endogenous money supply channels. The analytic models also consider the impact of fiscal policy and the current account balance on reserves. The test results reveal a unilateral causality from loan to reserve and a bilateral causal relationship between loan/reserve and Lf/deposit ratio. These results suggest that both accommodationist and structuralist channels coexist in Korea. However, the structuralist channel explains a relatively small portion of the endogenous money supply process. The IRF analysis does not provide evidence for the pressure on the interest rate spread exerted by financial institutions’ portfolio adjustment. This result can be attributed mainly to the central bank’s growing accommodative attitude toward the reserve demand.

Study the effects of ferrous materials inside wood on the propagation characteristics of acoustic emission signals

ABSTRACT This study compares the propagation characteristics of acoustic emission signals for wood containing ferrous material by implanting ferrous nails into wood specimens to investigate the acoustic emission (AE) detection method of foreign metal objects inside the wood. It obtains specimens for the comparative test by drilling holes and implanting ferrous nails into identical Zelkova schneideriana and Pinus sylvestris var. mongholica specimens. Initially, the AE source is generated by conducting pencil-lead break (PLB) tests on the specimen surfaces according to ASTM standards, and the AE signals are then collected at the specimen surface with a 1 MHz sampling frequency. The effects of ferrous materials on the propagation characteristics of AE signals are examined using FFT and EWT methods for the time–frequency analysis of the original AE signals. Finally, the signal generator produces the 150 kHz pulse train at the PLB location. The AE signal energy is calculated based on the alternating current principle to establish the corresponding AE energy attenuation function. The results showed that the proportion of AE signals in the frequency ranges of (30–60 kHz) and (150–180 kHz) increases significantly when ferrous nails are present in the specimens.

The Relationship between Energy Consumption, CO2 Emissions, Economic Growth, and Health Indicators.

The health and wellness of people through life expectancy, mortality rate improvement, and sustaining the productivity of labor contributes a lot to national income. Infrastructure development consumes energy and releases carbon dioxide at different stages of the construction process. The current study explores the nexus between CO2 emission, energy consumption, mortality, life expectancy, and GDP in the top five carbon-emitting countries by using time series data from 1975 to 2015. The study used a cointegration technique to find the long- and short-run relationships between study variables. The study also used a structural break test to identify the break time. The results of the correlation matrix show strong positive correlation between CO2 emissions and energy consumption. It also reflects a weak correlation with mortality and life expectancy in Japan and Russia. The results of the ADF test indicated that the series are stationary at first difference and provided evidence to use Johansen cointegration test for long- and short-run relationships between independent series. Vector error correction term and ECT method are used to find long-run relationships between cointegrated series and adjustment parameters. For the structural breaks of health indicators and energy consumption study, we used the Gregory Hanson structural break. Mortality rate and life expectancy rate of China, U.S., Russia, India, and Japan show relevant policy changes with economic policies of each country.

Risks in Major Cryptocurrency Markets: Modeling the Dual Long Memory Property and Structural Breaks

This study estimates the effects of the dual long memory property and structural breaks on the persistence level of six major cryptocurrency markets. We apply the Bai and Perron structural break test, Inclán and Tiao’s iterated cumulative sum of squares (ICSS) algorithm, and the fractionally integrated generalized autoregressive conditional heteroscedasticity (FIGARCH) model, with different distributions. The results show that long memory and structural breaks characterize the conditional volatility of cryptocurrency markets, confirming our hypothesis that ignoring structural breaks leads to an underestimation of the persistence of volatility modeling. The ARFIMA-FIGARCH model, with structural breaks and a skewed Student-t distribution, fits the cryptocurrency market’s price dynamics well.

The effect of political and bureaucratic regime changes on Australia's real interest rate

We attempt to find out if changes in political and bureaucratic regimes lead to significant mean shifts in the Australian short-term real interest rate, using quarterly data for the period 1970:3 to 2019:1. Utilising a sophisticated structural break test, three distinct structural breaks are found in Australia's real interest rate. The empirical results show that a model estimated to consider the shifts in the political regime explains more of the variation in the real interest rate compared to a model that incorporates shifts in the bureaucratic regime. Results from several non-nested model selection tests also confirm this finding.

ANALYSIS OF SHOCK PERSISTENCE IN BRAZILIAN ORANGE JUICE EXPORT

The present work aims to analyze the behavior of orange juice exports, in volume and monetary value, considering its main destinations, aiming to understand how these series behaved in the face of market shocks between 1997 and 2019. For that, the methodology used was based on the method proposed by Robinson et al. (1995a), which tests the presence of long memory across time series data, and on the structural break test proposed by Andrews and Ploberger (1994). According to the results, all analyzed series show no long memory. This result indicates that shocks that occurred in the period had a temporary effect on the flow of Brazilian orange juice exports, with no long-term effect on the trajectory of the series. These results allow us to conclude that the destinations analyzed here are solid markets for Brazilian orange juice export, and that short-term variations in export flows indicate a search for bargain prices among agents who purchase the Brazilian drink.

Improving Washable Woolen Fabric By Using Layer-By-Layer Coating

There are many different methods used in the industry to improve the antifelting and shrinkproof properties of wool blended fabrics. In the study, Layer-by-Layer technique used to improve the antifelting and shrinkproof properties of wool blended fabrics as an effective nanofabrication method according to the literature. Different polyelectrolytes and nano-polyurethane were applied on ecru and light, medium, dark color dyed suit wool blended fabrics by using Layer-by-Layer method. After the application fabrics, relaxation and felting shrinkage, breaking and tear strength tests and color/strength measurements were performed. Besides, the effect of squeezing roller velocity and pressure on the fabrics were evaluated. It is ensured that the relaxation and felting shrinkage values are within ± 3%. It has been observed that soft handle fabrics are obtained after coating without any negative effect on the fabric. In addition, SEM-EDX and FTIR-ATR analysis were performed to determine the surface properties of the fabrics and bond characterization of the films.

Impacts of rainfall variability in Gharb plain: Morocco

The Mediterranean climate is characterized by irregular rainfall, leading to both severe droughts and occasional flooding. This research aims to examine the changes occurring in the rainfall regime of the Gharb plain over thirty-three years, with specific attention given to three sites: El Menasra, Bel Ksiri, and Sidi Slimane. A range of methods were employed to understand the dimensions and impacts of rainfall in the study area. These methods include trend detection, testing for breaks, analysis of reduced annual anomalies, utilization of the Hyrfan Plus software, calculation of the Martone aridity index, assessment of the standardized rainfall index, and mapping flood zones. The findings of this study revealed that the Gharb Plain experienced periods of rainfall deficits, resulting in drought conditions during years with below-average rainfall. Conversely, years with above-average rainfall exhibited severe flooding, indicating the occurrence of two extreme phenomena that necessitate effective hydraulic management strategies. The main results showed that the rainfall trend is regressing, as the Nicholson, Martone, Emberger, and standardized precipitation indexes justify this regression. In addition, the plain has received an immense quantity of water from the Rif and Atlas Mountains, with the result that the study area has from time to time experienced severe flooding, as shown by the return periods detected, The Gharb plain has therefore experienced a rainfall deficit (drought) in years with below-average rainfall, while years with above-average rainfall have seen severe flooding, putting the country under two extreme phenomena requiring hydraulic management.

Reconfigurable Large-Current and High-Voltage Test Bench for HVDC Circuit Breaker Verification

This article presents a novel circuit configuration of a high-voltage direct current circuit breaker (HVdcCB) test bench that is based on a modified H-bridge modular multilevel cascaded converter (MMCC). The modified MMCC is composed of fewer H-bridge cells, and it can be reconfigured during operation to allow the proposed test bench to output large current or high voltage for the current breaking and dielectric withstand tests. Although simultaneous output of large current and high voltage is not possible, the maximum transient interrupt voltage (TIV) withstand test can be performed with reduced ratings. The controllable output allows generation of complex waveforms to simulate a wide range of fault conditions. Furthermore, the modified MMCC has some inherent safety features that can reduce the need for additional protective equipment in case of operational failure of the HVdcCB. In contrast, the conventional charged capacitor and inductor-based designs cannot generate arbitrary waveforms, are only suitable for current breaking tests, and require additional circuits to generate initial conditions for the HVdcCB. AC short-circuit generator-based designs offer one degree of freedom for control of the output waveforms and can sustain the maximum TIV withstand test. However, the ac output is unsuitable for the dielectric withstand test, and additional circuits are required to provide initial conditions for the HVdcCB. The proposed test bench circuit configuration is verified using a downscaled experimental test bench that consists of a total of nine H-bridge cells with an equivalent switching frequency of 92.5 kHz.

Experimental characterization, modelling and simulation of ae signal due to crack propagation in PMMA

Acoustic Emission (AE) is a non-destructive instrumentation that allows the detection of cracking, which dissipates elastic waves resulting from local crack-induced displacement jumps within the material. However, based on the AE experiments, a link between the crack fracture mechanics and the AE features is difficult to establish quantitatively, especially under quasi-static and dynamic loading conditions. Numerical simulations have proved to be very promising for this purpose. In this study, Pencil-Lead Break (PLB) tests are carried out on PMMA plate specimens with different thicknesses in order to determine the damping characteristics of PMMA and experimentally validate the AE numerical simulations. The influence of the specimen thickness, the distance between the sensor/source and the type of sensors on the measured acoustic emission are also studied.

Foreign direct investment and macroeconomic factors: evidence from Indian economy

The World Investment Report for 2017 released by UNCTAD projected that FDI inflows to developing Asian countries will increase by 15% in 2017, to $515 billion. With a boost in investor confidence in the economic outlook in major Asian economies, India is the second most preferred destination in the world as regards FDI inflows. This paper examines the relationship between FDI and macroeconomic factors, like, GDP, FER, employment, exports, and GCF for the period 1978-1979 to 2016-2017. Techniques like augmented Dickey-Fuller test, multivariate regression analysis Johansen's co-integration test, impulse response analysis and Chow breakpoint test, multiple breakpoint test and Bai-Perron sequentially determined breaks test are used. The findings suggest that there is a significant correlation between FDI and the macroeconomic factors. The results of Johansen's co-integration test reveal that there is a long run causal relationship between FDI and other variables.

Autonomous healing by vascular networks: tracking of cracks interaction by Ultrasounds and Acoustic Emission

The tracking of healing on concrete slabs where dense crack patterns are formed under bending is reported using Acoustic Emission (AE) and Ultrasound Pulse Velocity (UPV). Additively manufactured polymeric networks are designed to distribute a polyurethane agent through capillary actions and under pressure to the open cracks, formed in the slabs. It is shown that the crack pattern is controlled by the geometry of the vascular networks that are positioned near the steel reinforcement. The activation of both conventional linear and interlinked web-shaped networks is monitored by AE, however in both cases the load at which the initial cracks form is lower in series with embedded networks compared to the reference series, an indication of an overall weakening effect. The area where the healing agent circulates is larger (300x400 mm2) than past tests on beams, but only local healing is evident by UPV mapping. An indirect proof of cracks filling with stiffened agent is provided by the AE pencil-lead breaking test, as the amplitude recovery after healing can be linked to crack closure. This preliminary work evaluates the design of 3D printed vascular networks, but also explores the potential of AE and UPV as inspection tools in healing studies.

Can a sperm selection technique improve embryo ploidy?

Spermatozoa with the highest motility retain a superior genomic integrity, and elevated sperm chromatin fragmentation (SCF) has been linked to a lower ability of the conceptus to develop and implant. Therefore, the utilization of a sperm selection method, such as microfluidic sperm selection (MFSS), is capable of reducing the SCF by yielding the most motile fraction of spermatozoa with the highest embryo developmental competence. What remains unclear, however, is the causal mechanism that linksSCF to an impaired embryo development. To identify a relationship between SCF and an unexpectedly high proportion of embryo aneuploidy, while addressing treatment options. We identified couples with a high incidence of embryo aneuploidy in a previous intracytoplasmic sperm injection (ICSI) cycle with pre-implantation genetic testing for aneuploidy (PGT-A), utilizing spermatozoa selected by density gradient (DG). Terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) and neutral Comet assays were carried out on the semen specimens to assess total SCF and double-stranded DNA (dsDNA) fragmentation, respectively. These couples underwent subsequent ICSI/PGT-A cycles with MFSS. Total SCF and dsDNA fragmentation were compared between the two sperm selection methods. Embryo aneuploidy, implantation, clinical pregnancy, delivery,and pregnancy loss rates were compared between the couples' historical DG and subsequent MFSS cycles. In 57 couples undergoing 71 ICSI/PGT-A cycles, where DG sperm selection was carried out, a high incidence of aneuploid embryos (74.7%) resulted in poor implantation and no viable pregnancies. Testing for SCF, inclusive of dsDNA breaks, evidenced a SCF of 26.2% and dsDNA break of 3.6% in the raw specimen, that decreased to 18.0% (p < 0.001) and 3.1%, respectively, in the DG processed specimen. Following MFSS, total SCF and dsDNA fragmentation decreased to 1.9% and 0.3%, respectively (p<0.001). The embryo euploidy rate remarkable improved from 25.3% in the DG cycles to 42.9% in the MFSS cycles (p<0.001). The 6.7% implantation rate in the DG cycles increased to 65.5% in the MFSS cycles (p<0.001). Similarly, the clinical pregnancy rate rose from 10.5% (DG) to 64.6% (MFSS), resulting in a 62.5% delivery rate (p<0.001). In couples with a relatively young female partner with a negative infertility workup, and a male partner with semen parameters adequate for ICSI, presenting with a high rate of embryo aneuploidy, an additional subtle male factor component may be the culprit. Thus, it is crucial to assess the SCF and test for the dsDNA breaks, which can eventually contribute to embryo chromosomal abnormalities. Given the inverse relationship between SCF and motility, a selection of the most motile gamete by MFSS enhanced the proportion of spermatozoa with an intact genome, contributing to the generation of moreeuploid embryos that are capable of implanting and yielding increased term pregnancies.