Possibility Of Structural Changes Research Articles

전력 수요 시계열 분석과 장기예측

This study considers the time series characteristics in residential electricity demand function and forecasts long-run electricity demand in Korea. It is widely known that electricity demand and its determinants are unit root processes, so that estimating and forecasting the electricity demand function based on cointegration relationship are common in empirical analyses. We apply unit root tests on monthly time series data for the period 2006:01-2022:12. Korea has experienced the rapid development and social changes over this period, which provides convincing evidence of the possibility of structural changes. The unit root test of Dickey, Fuller (1979) tends to be biased in favor of non-rejection of the unit root null hypothesis if the process considered is trend-stationary with a slope change. What we found is that electricity demand and its determinants are trend-stationary processes allowing for a slope change, whereby there is no need to invoke either cointegration regression model or error-correction model under the unit root assumption. We apply a regression model with a structural change to estimate the residential electricity demand function and forecast the long-run electricity demand for the period 2023-2050.

Analysis of Interaction Characteristics Between Amyloid β and Lecanemab by HDX‐MS

AbstractBackgroundSoluble amyloid‐β (Aβ) aggregates including protofibrils (PFs) have been reported to be more toxic than insoluble fibrils. Recently, pharmaceutical antibodies targeting these soluble Aβ aggregates have been developed. The structural dynamics and heterogeneity of soluble Aβ aggregates have made it difficult to analyze the structural characteristics and tertiary structure. To investigate conformational recognition of lecanemab to Aβ aggregates, the structural characteristics of Aβ PFs and their change upon binding to lecanemab, an antibody with preferential binding to Aβ protofibrils, were studied using hydrogen‐deuterium exchange mass spectrometry (HDX‐MS).MethodAβ (1‐42) PFs were prepared in vitro. The hydrogen/deuterium (H/D) exchange status for Aβ (1‐42) PFs and monomeric Aβ (1‐40) were studied by HDX‐MS in phosphate buffered saline (PBS) to explore characteristics of their regional structural dynamics. The effects of the anti–Aβ PF antibody lecanemab on H/D status of Aβ (1‐42) PFs and monomeric Aβ (1‐40) were studied to explore the structural basis for the characteristics of antibody‐ Aβ interaction and specificity against Aβ PFs.ResultAβ (1‐42) PFs were more protected from H/D exchange throughout the molecule than monomeric Aβ (1‐40), though the N‐terminal and the mid region of Aβ still showed relatively higher H/D exchange in Aβ (1‐42) PFs. Upon interaction with lecanemab, the mid region of Aβ (1‐42) PFs was also protected further in addition to the N‐terminal region, and its protection level of Aβ (1‐42) PFs was higher than monomeric Aβ (1‐40). The higher protection from H/D exchange both on N‐terminal and mid regions of Aβ PFs is considered to be characteristics of interaction between Aβ (1‐42) PFs and lecanemab.ConclusionThe results indicate that the mid region of Aβ has relatively high flexibility in PFs in addition to N‐terminal region. The mid region is suggested to be involved in the interaction with lecanemab as well as its N‐terminal region, and the conformational epitope formation was expected, though there are still possibility of structural change in the mid region upon lecanemab binding. The results indicated that the combinational action on the N‐terminal and mid regions of Aβ are involved in the modulation of Aβ PFs by lecanemab.

In situ NMR Investigation of the Photoresponse of Perovskite Crystal

Summary Hybrid perovskites are outstanding candidates for use in optoelectronic devices. Nonetheless, hybrid perovskites present numerous fundamental issues that are not yet fully understood. This study seeks to address this problem by reporting on the occurrence of ultraslow dynamic orientation changes in the methylammonium (MA) cations and the corresponding changes in the inorganic lattice of MAPbI3 perovskite crystals occurring over a time scale of 100 s under continuous illumination based on in situ single-crystal 2H nuclear magnetic resonance and in situ X-ray diffraction results. The demonstrated ultraslow dynamic changes in MAPbI3 are far slower than elementary molecular motions typically having time scales of femtoseconds and picoseconds and have never been reported previously. The ultraslow dynamic changes have been correlated with the reduction of band gap and the increase of absorption coefficient of MAPbI3, providing the molecular origins of the stabilization process in the photoresponse of the MAPbI3 device.

Measuring Dynamic Structural Changes of Nanoparticles at the Atomic Scale Using Scanning Transmission Electron Microscopy.

We propose a new method to measure atomic scale dynamics of nanoparticles from experimental high-resolution annular dark field scanning transmission electron microscopy images. By using the so-called hidden Markov model, which explicitly models the possibility of structural changes, the number of atoms in each atomic column can be quantified over time. This newly proposed method outperforms the current atom-counting procedure and enables the determination of the probabilities and cross sections for surface diffusion. This method is therefore of great importance for revealing and quantifying the atomic structure when it evolves over time via adatom dynamics, surface diffusion, beam effects, or during insitu experiments.

Stability of carbon monoxide oxidation process on gold nanoparticles

The stability conditions for mathematical models of carbon monoxide oxidation on the surface of gold nanoparticles are investigated. The cases of reaction mechanisms of one-step and step-by-step transformation of reagents are consecutively considered. Using the stability analysis by Lyapunov method, it is shown that models which take into account the possibility of structural changes of the catalyst surface can predict the occurrence of oscillatory mode in the system as a result of Hopf instability.

Designing and construction of novel variants of Chondroitinase ABC I to reduce aggregation rate

Chondroitinase ABC I (cABC I) can degrade inhibitory molecules for axon regrowth at the site of damage after spinal cord injury (SCI). One of the main problems in the practical application is the possibility of structural changes that lead to the inactivation of the enzyme. In current work, three variants of cABC I was designed and constructed by manipulation of a short helix conformation (Gln678-Leu679-Ser680-Gln681); where Gln residues were converted to Glu. According to the enzyme kinetics studies, the catalytic efficiency of the Q681E and double mutant (Q678E/Q681E) increases in comparison with WT enzyme; while that of Q678E decreases. It was also shown that the rate of the inactivation of the enzyme variants over time is greater in WT and Q678E variants than that of the Q681E and double mutant. Negative values of entropy change of thermal inactivation measurements; demonstrate that inactivation of the WT and Q678E variants are mainly originated from aggregation. These observations can be explained by considering the repulsive electrostatic interaction between enzyme molecules that prevents protein aggregation over time. It is concluded that increasing the solubility of the Q681E and double mutant via favorable interactions of surface-exposed charged residues with dipole momentum of water molecules accompanied by the presence of intermolecular repulsive electrostatic interaction leads to decreasing the rate of aggregation in both long-term storage and heat-induced structural changes.

Drivers of global industrial changes in the context of the behavioral economics

The article defines the main drivers of global industrial change in the context of behavioral economics. The author analyzes the literary sources and highlights the positive and negative consequences of the introduction of innovative technologies created in the course of the fourth industrial revolution. The essential features and content of the fourth industrial revolution as the driving force of the development of the world economy and economy of Ukraine are considered. The essence of the changes taking place in Ukraine and in the world in the conditions of globalization is analyzed. The possibilities of structural changes of the national economy in the conditions of the fourth industrial revolution are estimated. The obtained results develop the theory of innovative management in the part of the formation of the preconditions for managing the choice of strategies of innovative development in the conditions of the fourth industrial revolution. Possible directions of business development for Ukrainian enterprises are offered on the basis of evaluation of the main tendencies of development of the world economic system. The results of their systematization can be used as the basis for the formation of an information base for identifying the priority directions of innovation development. Further research should be aimed at forming of a mechanism for ensuring the social and economic development of Ukraine in the conditions of the fourth industrial revolution. The paper proves that for the development of the digital economy of Ukraine it is necessary to start a large-scale digitalization of all branches as soon as possible, investing the most in the development of digital infrastructure, innovations and modern technologies. Therefore, every effort should be made to ensure the success of Ukrainian innovation companies and those who invest in Ukraine.

Cointegration with structural changes between per capita product and income inequality in Mexico

The long-run relationship between per capita product and income inequality in Mexico is assessed for the period 1963–2010. The methodology consists of stochastic unit root techniques with structural changes. The integration and cointegration tests suggest that it is not possible to understand this link if the possibility of structural changes is not taken into account. Causality, running from per capita product to income inequality, and a negative and significant overall effect are estimated. However, after the regime shifts – mainly estimated to occur in the 1980s – the connection is no longer meaningful. This result seems to be linked to the slow growth of the Mexican economy after these structural breaks, affecting, in turn, the reductions in income inequality.

Stochastic change-point ARX-GARCH models and their applications to econometric time series

This paper shows that the commonly encountered volatility persistence in fitting GARCH models to financial time series can arise if the possibility of structural changes is not incorporated in the time series model. To avoid spurious memory in modeling volatilities of econometric time series, we consider two time-scales and use the short time-scale to define GARCH dynamics and the long time-scale to incorporate parameter jumps. This leads to a Bayesian change- point ARX-GARCH model, whose unknown parameters can undergo occasional changes at unspecified times and can be estimated by explicit recursive formulas when the hyperparameters of the Bayesian model are specified. Efficient estimators of the hyperparameters of the Bayesian model are developed, yielding empirical Bayes estimates of the piecewise constant parameters in the stochastic change- point model. The empirical Bayes approach is applied to the frequentist problem of partitioning the time series into segments under sparsity assumptions on the change-points. Simulation and empirical studies of its performance are also given.

Computer modelling of undoped and Eu3+‐doped LiLa(WO4)2

AbstractIn this work, computer modelling of the undoped and Eu3+‐doped LiLa(WO4)2 structure was successfully achieved by energy minimization and mean field theory. The results were compared with experimental data previously published and are in good agreement with them. A linear regression of the lattice parameters was also proposed as a function of the dopant concentration. The lattice ordering was evaluated to understand the possibility of structural changes in the crystal. Regarding the optical luminescence, the concentration limit of Eu doping was also determined. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Testing the validity of the monetary model for ASEAN with structural break

This study examines the validity of the long run structural relations underlying the monetary exchange rate model for Malaysia, Singapore, The Philippines and Thailand. Take into consideration the possibility of structural change, we examined the models using recent developed techniques of testing unit root and cointegration with a structural break. Our findings of three cointegrating relations among the variables in the system were further identified by testing theoretical restrictions on the cointegrating equations. The long run relationships were able to be interpreted according to the theory, hence, support the long run validity of the monetary exchange rate model.

Cation distribution and micro level magnetic alignments in the nanosized nickel zinc ferrite

Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized through sol–gel synthesis method. Sintering at elevated temperatures was employed to obtain samples with higher particle sizes. The structural characterization using X-ray diffraction suggests that the three samples possess uniformal cation distribution. The variation of magnetization as a function of applied magnetic field at room temperature is studied using a vibrating sample magnetometer and all the samples found to exhibit nearly zero remanence and zero coercivity suggesting a superparamagnetic behaviour. The variation of magnetizations of the three different samples with temperature was studied by ZFC–FC technique at two different applied fields of 10Oe and 1000Oe. In order to study the possibility of structural changes, chemical and coordination differences of iron in the nanocrystalline Ni–Zn ferrite particles, room temperature 57Fe Mössbauer spectroscopy study was used. The application of 5T magnetic field at 5K temperature resolves the two sub spectra and canting angle of 27o and 12o were observed which clearly indicates the noncollinear magnetic alignment in nano crystallites of Ni0.5Zn0.5Fe2O4. The neutron diffraction study was performed at seven different temperatures 20, 50, 100, 150, 200, 250 and 300K. Rietveld refinement of the neutron diffraction data was performed to deduce the basic structural parameters, cation distribution and micro level magnetic alignments in the nanosized nickel zinc ferrite.

Integration Test of HK dollar and RMB and Its Interest Rate Linkages An Empirical Study Based on Structural Change

Taking into account the possibility of structural changes led by RMB exchange rate reform, the paper tests the data of interest rate relationship between Hong Kong and Mainland China and U.S. from July 1996 to October 2009, and finds that there is different data structure before and after the July 2005 reform of the RMB exchange rate. So, in this paper, UIP-PPP-RIP model is used for testing empirically the monetary integration between Hong Kong and Mainland before and after the exchange rate reform, and it is concluded that: before the exchange rate reform the parity existed between Hong Kong and Mainland in the financial market, commodity market and real capital market, then after the exchange reform the parity disappeared. In addition, dynamics analysis of the long and short term interest rate relationship between the three locations shows that: U.S. interest rate change effect on Hong Kong interest rate is larger than Mainland interest rate change effect on Hong Kong interest rate, but this effect after the exchange rate reform became smaller. The policy significance is that monetary integration does not in appear Hong Kong and Mainland after the exchange rate reform, but the RMB interest rate impact on the Hong Kong dollar interest rate is gradually increased.

Synthetic Floating Crude Oil Storage and Optimal Statistical Arbitrage: A Model Specification Analysis

The informational fl ow between oil and spot freight markets is examined in a novel way via the time charter equivalent (TCE) to identify statistical arbitrage trading opportunities. Using Brent and TD3 data, synthetic floating storage positions are constructed, which are shown to be cointegrated with Brent futures prices of common maturity. A comprehensive model specification analysis of the optimal statistical arbitrage trading model of Bertram (2010) is performed on this data. Model misspecification in the underlying Gaussian Ornstein-Uhlenbeck (OU) process is identified. Evidence of threshold effects and the possibility of structural change in the cointegration relationships is presented.

Studying on the monetary transmission mechanism in China in the presence of structural changes

PurposeThis paper aims to study the monetary transmission mechanism of China from January 1996 to December 2009 under endogenous structural breaks.Design/methodology/approachThe study constructs a benchmark VAR model and then adds the proxy variables for four channels of monetary policy transmission as endogenous or exogenous variables in the model to study the transmission mechanism in China. Considering a number of reforms carried out in the economic and financial field in the past two decades and the possibility of structural changes in the monetary transmission mechanism, the methodology proposed by Qu and Perron is employed to allow for endogenous structural changes in the model.FindingsBy conducting a comparative analysis, conclusions can be drawn from this paper that bank lending is always the dominating channel for monetary policy to influence economy in China and the roles of the interest rate channel and the exchange rate channel have been improved in recent years. However, the role of the asset price channel in monetary policy transmission has weakened since late 2001.Originality/valueThis paper combines the quasi‐maximum likelihood procedure proposed by Qu and Perron in 2007 with a benchmark VAR model, thus providing a new approach to study monetary transmission mechanism and the conclusions can be more sensible.

An NMR study of the N‐terminal domain of wild‐type hERG and a T65P trafficking deficient hERG mutant

The human Ether-à-go-go Related Gene (hERG) potassium channel plays an important role in the heart by controlling the rapid delayed rectifier current. The N-terminal 135 residues (NTD) contain a Per-Arnt-Sim (PAS) domain and an N-terminal amphipathic helix. NMR relaxation analysis and H/D exchange experiments on the NTD demonstrated that the amphipathic helix is rigid and solvent accessible. An NTD containing a T65P mutation, which causes a hERG channel trafficking deficiency, was purified from E.coli. The mutant protein did not aggregate in gel filtration analysis and the amide cross peaks of its residues disappeared in an HSQC spectrum indicating the possibility of structural changes. A carbon chemical shift comparison of the residues with cross peaks in the HSQC spectrum showed no clear difference between the purified wild-type protein and the purified mutant. There were multiple conformations observed for the T65P mutant protein at high temperatures from HSQC experiments and a thermal stability assay showed that the T65P mutation reduced the thermal stability of NTD. This instability may affect protein folding or structural dynamics of other regions.

Study on needle‐punched nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. Part III: filtration characteristics

This paper reports the filtration behaviours of needle‐punched bulked nonwoven fabrics made from shrinkable and non‐shrinkable acrylic blends. The basic idea of the present work is to explore the possibility of structural changes in needle‐punched nonwoven fabrics made from blends of shrinkable and non‐shrinkable acrylic fibres, as in the case of an acrylic bulked yarn, to improve the filtration behaviour. In Part I and Part II of this series, compressional and transmission characteristics of these fabrics were reported, respectively. The effects of variables, namely fabric areal density, needle punch density and the proportion of shrinkable acrylic fibre in the blend, on various filtration‐related properties of needle‐punched nonwoven fabrics have been studied by relaxing the shrinkable component of the fabric using hot steam treatment. A three‐variable factorial design technique proposed by Box and Behnken was used to investigate the combined interaction effect of the above variables on the filtration properties of these fabrics. The fabric areal density and needle punch density were found to have a significant effect on filtration efficiency as well as pressure drop. The proportion of shrinkable acrylic fibre has little effect on filtration efficiency, but the trends are dependent on the needle punch density.

On the Sustainability of Government Deficits: Some Long-Term Evidence for Spain, 1850–2000

We provide a test of the sustainability of the Spanish government deficit over the period 1850–2000, from the estimation of a cointegration relationship between government expenditures and revenues derived from the intertemporal budget constraint. The longer than usual span of the data allows us to obtain more robust results on the fulfilment of the intertemporal budget constraint than most of the previous analyses. Two additional robustness checks are provided. First, we investigate the possibility of structural changes occurring along the period analyzed, using the new approach of Kejriwal and Perron (2008, 2010) to testing for multiple structural changes in cointegrated regression models. Second, we investigate whether the behaviour of fiscal authorities has been non-linear, by means of the procedure of Hansen and Seo (2002) based on a threshold cointegration model. Our results show that (i) the government deficit has been strongly sustainable in the long run, (ii) no evidence is found on any significant structural break throughout the whole period, and (iii) fiscal sustainability has been attained due to the non-linear behaviour of fiscal authorities, which have only acted on the budget deficit when it has exceeded around 4.5% of GDP.

Internal pressure profiling of medical bandages

The present paper reports the characteristics of internal pressure exerted by bandages, measured over a period of time for a special class of bandages called compression bandages. The basic idea of this work is to explore the possibility of structural changes in these bandages to improve the compression characteristics of these bandages and provide a very accurate method of measurement of pressure applied by these bandages. The effects of variables, namely fabric construction, hardness of surface below the bandage (i.e. simulation of the wide range of human physical structures), bandage width and style of wrapping (i.e. the overlap and the direction of wrapping, from the knee towards the ankle and vice versa), have been studied by using a prototype designed and developed based on pneumatic principle. Based on the results, certain characteristics have been recommended for choosing the ideal bandages and wrapping styles.

Bayesian Methods for TFP Analysis of a Multi-Region Economy with Dynamic Structure and Application to Japan

In this paper, we present the Bayesian methods for total factor productivity (TFP) analysis of a multi-region economy with dynamic structure. Conventional approaches to the empirical analysis of regional economic growth are incapable of providing an appropriate description of the behavior of TFP. Accordingly, we introduce a set of Bayesian statistical models based on regional production functions. In our framework, TFP is regarded as a time-varying parameter, and is estimated using a Bayesian smoothness priors approach. Compared with conventional approaches, this application of a Bayesian method makes it possible to analyze the behavior of TFP in detail. In addition, we take into account the fact that elasticity of output with respect to factors of production may vary across regions, implying a structural heterogeneity among the regions. Further, the possibility of structural changes in regional economies is incorporated. As an empirical application, we present the results for an analysis of Japanese prefectural data.