Exchange Fluctuations Research Articles

Effects of Hyporheic Water Exchange on Microbial Community Structure and Function: A Case Study in the Beiluo River, Loess Plateau, China

ABSTRACT Microbial communities in riverine hyporheic zones provide essential ecosystem services. However, the mechanisms whereby they respond to hyporheic water exchange under different habitat stress conditions remain poorly understood. Therefore, investigating the impact of riverine hyporheic exchange on the microbial community composition and its potential ecological function is essential, particularly in the seasonal rivers of northern China. To elucidate the structure and function of hyporheic zone sediment microbial communities in response hyporheic exchange and environmental fluctuations, we examined associations by performing in situ falling‐head permeameter tests and eDNA techniques. The primary findings were as follows: (1) We detected variations in the spatial distribution patterns of streambed hydraulic conductivity (range, 0.055–3.490 m/day) and vertical fluxes (range, 1.886–342.0 mm/day) among different monitoring stations. (2) Microbial communities displayed compositional similarities and spatial heterogeneity. Stations with limited vertical exchange were characterised by reduced species diversity. (3) Prokaryotes showed better modularity characteristics with higher stability and functional diversity than eukaryotic communities. (4) Differences in the abundance of microbial metabolism and genetic functions were observed among different habitats. This study emphasises the significance of local hydrological patterns (such as downwelling) in maintaining riverine environmental elements and acting as hotspots for microbial diversity within the hyporheic zone. The heterogeneity of the hydrological patterns governing hyporheic water exchange can explain the abundance, species diversity and biogeochemical processes of microorganisms within this zone.

Analysis of the influence of macroeconomic factor on long-term and short-term fluctuation of the Indonesian stock exchange (BEI) using the error correction method (ECM) approach

This research aims to empirically test the influence of the short-term equilibrium relationship and long-term equilibrium relationship of economic growth, interest rate, inflation, and exchange rate on IHSG (IDX Composite) using empirical Error Correction Model (ECM) data from 2000 to 2023. During the observation period, the macroeconomic variables showed no significant influence on the movement of the IHSG (IDX Composite) in the short-term equilibrium relationship, whereas in the long-term equilibrium relationship almost all variables, namely economic growth, interest rate, and exchange rate, had a significant influence on the IHSG ( IDX Composite), while inflation has no short or long term effect on the IHSG.

Refined Strategies: Financial Risk Management in the Realm of International Business

Financial risk management in the realm of international business holds immense significance within the global marketplace. This study delves into the diverse financial risks encountered by multinational corporations (MNCs) as they operate across various markets. These risks encompass currency exchange fluctuations, interest rate fluctuations, political and regulatory uncertainties, market volatility, and credit vulnerabilities. The study assesses the efficacy of conventional financial risk management methods in addressing these challenges and investigates how geopolitical dynamics influence risk management strategies for MNCs.The research methodology adopts a descriptive approach utilizing secondary sources, emphasizing structured data presentation relevant to present-day conditions. The analysis covers the nature and origins of financial risks, established risk management practices, and the impact of geopolitical variables on risk management strategies. The findings highlight the critical role of proactive risk assessment, holistic risk mitigation tactics, and the ability to adapt to geopolitical shifts in ensuring sustainable financial outcomes in international business endeavors.

COMPARATIVE ANALYSIS OF FX AND GOLD RESERVES AMONG MAJOR ECONOMIES: A STUDY FROM Q1 2020 TO Q1 2024

In order to identify fluctuations, management approaches, correlations, and trends, this research examines the foreign currency (FX) and gold reserves of China, Japan, Switzerland, the United States, and India from Q1 2020 to Q1 2024. We found notable fluctuations in Switzerland's foreign exchange reserves via analysis of quarterly data, whereas the United States gold holdings remained steady. We discovered significant variations in resource management techniques using descriptive statistics and ANOVA. We also observed high cross-national correlations, indicating common impacts and interrelated economic policies. The results show that whereas China's changing gold holdings show a more flexible response to changes in the economy, the USA and Switzerland maintain steady gold reserves, indicating cautious financial tactics. According to the report, nations with high levels of volatility should diversify their reserve assets, adopt cautious approaches, improve international economic coordination, evaluate policies on a regular basis, and use predictive analytics to foresee changes in the economy. This research highlights the necessity for flexible and coordinated policies to sustain economic stability in a globally linked financial system. Overall, it offers insightful information on the reserve management procedures of major countries. By maximizing reserve management, policymakers may reduce risks and seize opportunities in a changing economic landscape. This is the goal of the proposals made here.

Exploring the interconnection between international crude oil and silver rates volatilities: Novel evidence from the COVID-19 pandemic

Several research studies globally focus on the volatility of gold and oil prices, neglecting an examination of silver price volatility in relation to other market commodities. The current Covid-19 pandemic has led to various uncertainties and fluctuations in financial and stock exchange markets, yet existing literature primarily concentrates on individual product rates rather than combined rate changes. Our study aims to bridge this research gap by analyzing the relationship between oil rates, silver rates, oil rate transitions, and silver rate transitions on the security exchange in China from 1990 to 2022, using the ARDL approach and Nonlinear ARDL for a comprehensive assessment. The findings reveal a significant impact of silver and oil rates on China's security exchange in the future, with the negative effects of oil rate changes and a positive effect of silver rate transitions. In the short term, oil and silver rates play a crucial role in influencing China's security exchange, highlighting the importance of monitoring these trends for investors. It is recommended that investors respond prudently to market transitions, particularly by considering silver as a secure option during times of uncertainty, while policymakers should implement appropriate measures to manage the rapid fluctuations from oil to the security market.

The Financial Crisis Affecting the Construction Sector

Today's world is witnessing continuous development, particularly in the construction sector, which is meeting the rising population and their need for essential facilities; this is one of the reasons why construction is witnessing such development. Different crises significantly affect this sector, including the financial crisis in different countries. This paper identifies the financial crises, their categories, and the reasons for appearing them. Inflation, currency exchange fluctuations, and the drop in global oil prices are the most important reasons for the emergence of external financial crises, especially in Iraq, which considers oil an important economic resource for its budget. The unexpected global financial events led to an economic collapse that affected the construction sector. Many large projects in Iraq have been put on hold as a result of these conditions due to the country's lack of resources to address these crises. This paper aims to study and identify potential crises and potential responses and mitigation strategies for each crisis stage.

Climate forcing controls on carbon terrestrial fluxes during shale weathering

Climate influences near-surface biogeochemical processes and thereby determines the partitioning of carbon dioxide (CO2) in shale, and yet the controls on carbon (C) weathering fluxes remain poorly constrained. Using a dataset that characterizes biogeochemical responses to climate forcing in shale regolith, we implement a numerical model that describes the effects of water infiltration events, gas exchange, and temperature fluctuations on soil respiration and mineral weathering at a seasonal timescale. Our modeling approach allows us to quantitatively disentangle the controls of transient climate forcing and biogeochemical mechanisms on C partitioning. We find that ~3% of soil CO2 (1.02 mol C/m2/y) is exported to the subsurface during large infiltration events. Here, net atmospheric CO2 drawdown primarily occurs during spring snowmelt, governs the aqueous C exports (61%), and exceeds the CO2 flux generated by pyrite and petrogenic organic matter oxidation (~0.2 mol C/m2/y). We show that shale CO2 consumption results from the temporal coupling between soil microbial respiration and carbonate weathering. This coupling is driven by the impacts of hydrologic fluctuations on fresh organic matter availability and CO2 transport to the weathering front. Diffusion-limited transport of gases under transient hydrological conditions exerts an important control on CO2(g) egress patterns and thus must be considered when inferring soil CO2 drawdown from the gas phase composition. Our findings emphasize the importance of seasonal climate forcing in shaping the net contribution of shale weathering to terrestrial C fluxes and suggest that warmer conditions could reduce the potential for shale weathering to act as a CO2 sink.

Fuzzy analytic hierarchy process based generation management for interconnected power system

Decision makers consistently face the challenge of simultaneously assessing numerous attributes, determining their respective importance, and selecting an appropriate method for calculating their weights. This article addresses the problem of automatic generation control (AGC) in a two area power system (2-APS) by proposing fuzzy analytic hierarchy process (FAHP), an multi-attribute decision-making (MADM) technique, to determine weights for sub-objective functions. The integral-time-absolute-errors (ITAE) of tie-line power fluctuation, frequency deviations and area control errors, are defined as the sub-objectives. Each of these is given a weight by the FAHP method, which then combines them into an single final objective function. This objective function is then used to design a PID controller. To improve the optimization of the objective function, the Jaya optimization algorithm (JOA) is used in conjunction with other optimization techniques such as sine cosine algorithm (SCA), Luus–Jaakola algorithm (LJA), Nelder–Mead simplex algorithm (NMSA), symbiotic organism search algorithm (SOSA) and elephant herding optimization algorithm (EHOA). Six distinct experimental cases are conducted to evaluate the controller’s performance under various load conditions, with data plotted to show responses corresponding to fluctuations in frequency and tie-line exchange. Furthermore, statistical analysis is performed to gain a better understanding of the effectiveness of the JOA-based PID controller. For non-parametric evaluation, Friedman rank test is also used to validate the performance of the proposed JOA-based controller.

Investigation of rank order centroid method for optimal generation control.

Multi-criteria decision-making (MCDM) presents a significant challenge in decision-making processes, aiming to ascertain optimal choice by considering multiple criteria. This paper proposes rank order centroid (ROC) method, MCDM technique, to determine weights for sub-objective functions, specifically, addressing issue of automatic generation control (AGC) within two area interconnected power system (TAIPS). The sub-objective functions include integral time absolute errors (ITAE) for frequency deviations and control errors in both areas, along with ITAE of fluctuation in tie-line power. These are integrated into an overall objective function, with ROC method systematically assigning weights to each sub-objective. Subsequently, a PID controller is designed based on this objective function. To further optimize objective function, Jaya optimization algorithm (JOA) is implemented, alongside other optimization algorithms such as teacher-learner based optimization algorithm (TLBOA), Luus-Jaakola algorithm (LJA), Nelder-Mead simplex algorithm (NMSA), elephant herding optimization algorithm (EHOA), and differential evolution algorithm (DEA). Six distinct case analyses are conducted to evaluate controller's performance under various load conditions, plotting data to illustrate responses to frequency and tie-line exchange fluctuations. Additionally, statistical analysis is performed to provide further insights into efficacy of JOA-based PID controller. Furthermore, to prove the efficacy of JOA-based proposed controller through non-parametric test, Friedman rank test is utilized.

Contributions of atmospheric forcing and ocean preconditioning in the 2016 Antarctic sea ice extent drop

The 2016 Antarctic sea ice extent (SIE) drop was a rapid decrease that led to persistent low sea ice conditions. The event was triggered by atmospheric anomalies, but the potential preconditioning role of the ocean is unsettled. Here, we use sensitivity experiments with a fully-coupled regional climate model to elucidate the impact of the ocean conditions on the drop and on the persistence of the negative SIE anomalies during 2017. In particular, we re-initialize the model in January 2016 using different ocean and sea ice conditions, keeping lateral boundary forcings in the atmosphere and ocean unchanged. We find that the state of the Southern Ocean in early 2016 does not determine whether the drop occurs or not, but indeed has an impact on its amplitude and regional characteristics. Our results also indicate that the ocean initialization affects the sea ice recovery after the drop in the short term (one year), especially in the Weddell sector. The ocean’s influence appears not to be linked to the ocean surface and sea-ice initialization, but rather to the sub-surface conditions (between 50 m and 150 m) and heat exchange fluctuations at the regional scale, while the atmospheric forcing triggering the drop is driven by the large-scale circulation.

Coupled effect of injection position variation on gas exchange stability of a free-piston engine

Gas exchange fluctuations may lead to operation instability of the free-piston engine (FPE), because the engine has a coupling effect between the gas exchange and the piston motion, which is different from a conventional engine. It is, therefore, important to study the gas exchange instability to ensure the stable operation of the engine. This study focuses the effect of variable piston position when injecting on the gas exchange stability of a looped scavenging FPE, and a systematic full-cycle gas exchange model is presented by developing a dynamic model, a combustion model, and a multidimensional scavenging model. Meanwhile, an iterative method between motion and scavenging is used to solve the model numerically for gas exchange simulation, and the effects of variable piston position when injecting on piston motion, thermodynamic in cylinder, and gas exchange process are studied. The results indicate that retarding injection induces instability of gas exchange duration which first increases and then decreases, and there is an injection position which is most conducive to the increase of capture efficiency of gas exchange, although the scavenging efficiency is lowest under this condition. This result also suggests that more complete exhaust may be achieved by a different injection position.

Magnetic exchange, anisotropy and excitonic fluctuations in a [NiII7] Anderson wheel

Susceptibility and magnetisation measurements, magnetic neutron spectroscopy and first principles calculations reveal the presence of competing ferro- and antiferromagnetic exchange interactions and both easy plane and easy axis anisotropy in a [Ni7] Anderson wheel.

Upshot of Exchange Rate on Export and Import of Agricultural Production in Bangladesh

An important factor in trade is the currency's exchange rate and fluctuation of exchange rate is very concerning issue in current period over the world. Bangladesh, a developing economy, depends mostly on agriculture sector, recent period’s fluctuation of exchange rates of the country influences its export and import of the agricultural production. This research examines how the real exchange rate affects agricultural production's import and export between 1977 and 2015 in Bangladesh. Variables like Total Agricultural Production, Real Gross Domestic Product, Exchange rates, and Exports and Imports of Agricultural Product have been taken for this study. Ordinary Least Square Method (OLS) and other related econometrical techniques are applied to find the association among indicators. The research indicates that the exchange rate shows no discernible effect on the import and export of agricultural production in Bangladesh. However, Real Gross Domestic Product (GDP) of the country portraits no significant influence on agricultural exports while portraits positive significant influence on agricultural imports. This research contributes to appropriate policies and actions that must be implemented at an equitable level.

The effect of bilateral currency swap agreements on foreign capital inflows: Evidence from China

AbstractThis study empirically explores the effect of bilateral currency swap agreements (BCSAs) on foreign capital inflows. Using data on foreign enterprises' cross‐border investments in China over 2005–2020 released by Bureau van Dijk (BvD) Zephyr database, a multiperiod difference‐in‐differences (DID) estimation is used based on the signing of China's BCSAs over the period of 2009–2020. We find that the signing of BCSAs increases the total amount of foreign capital inflows by 9.97% and the number of foreign capital projects by 8.68% on average. Moreover, foreign capital inflows that come from economies with higher bilateral exchange fluctuations, fewer foreign exchange reserves, higher interest rates, higher tax rates, and lower institutional qualities are more responsive to the signing of BCSAs, especially for those horizontal capital inflows.

Temporal and Spatial Variations in Carbon Flux and Their Influencing Mechanisms on the Middle Tien Shan Region Grassland Ecosystem, China

Grassland ecosystems are an important component of global terrestrial ecosystems and play a crucial role in the global carbon cycle. Therefore, it is important to study the carbon dioxide (CO2) process in the Middle Tien Shan grassland ecosystem, which can be regarded as a typical representative of the mountain grasslands in Xinjiang. Eddy covariance (EC) and the global carbon fluxes dataset (GCFD) were utilized to continuously monitor the Middle Tien Shan grassland ecosystem in Xinjiang throughout the 2018 growing season. The findings revealed notable daily and monthly fluctuations in net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (Reco). On a daily basis, there was net absorption of CO2 during the day and net emission during the night. The grassland acted as a carbon sink from 6:00 to 18:00 and as a carbon source for the remaining hours of the day. On a monthly scale, June and July served as carbon sinks, whereas the other months acted as carbon sources. The accumulated NEE, GPP, and Reco during the growing season were −329.49 g C m−2, 779.04 g C m−2, and 449.55 g C m−2, respectively. On the half-hourly and daily scales, soil temperature (Ts) was the main contributor to CO2 fluxes and had the greatest influence on the variations in CO2 fluxes. Additionally, air temperature (Ta) showed a strong correlation with CO2 fluxes. The grassland ecosystems exhibited the strongest CO2 uptake, reaching its peak at soil temperatures of 25 °C. Moreover, as the air temperatures rose above 15 °C, there was a gradual decrease in NEE, while CO2 uptake increased. The applicability of GCFD data is good in the grassland ecosystem of the Middle Tien Shan Mountains, with correlations of 0.59, 0.81, and 0.73 for NEE, GPP, and Reco, respectively, compared to field observations. In terms of remote sensing spatial distribution, the Middle Tien Shan grassland ecosystem exhibits a carbon sink phenomenon.

Arbitrary-time thermodynamic uncertainty relation from fluctuation theorem.

The thermodynamic uncertainty relation (TUR) provides a universal entropic bound for the precision of the fluctuation of the charge transfer, for example, for a class of continuous-time stochastic processes. However, its extension to general nonequilibrium dynamics is still an unsolved problem. We derive TUR for an arbitrary finite time from exchange fluctuation theorem under a geometric necessary and sufficient condition. We also generally show a necessary and sufficient condition of multidimensional TUR in a unified manner. As a nontrivial practical consequence, we obtain universal scaling relations among the mean and variance of the charge transfer in short time regime. In this manner, we can deepen our understanding of a link between two important rigorous relations, i.e., the fluctuation theorem and the thermodynamic uncertainty relation.

Heat distribution in quantum Brownian motion.

We investigate the heat statistics in a relaxation process of quantum Brownian motion described by the Caldeira-Leggett model. By employing the normal mode transformation and the phase-space formulation approach, we can analyze the quantum heat distribution within an exactly dynamical framework beyond the traditional paradigm of Born-Markovian and weak-coupling approximations. It is revealed that the exchange fluctuation theorem for quantum heat generally breaks down in the strongly non-Markovian regime. Our results may improve the understanding about the nonequilibrium thermodynamics of open quantum systems when the usual Markovian treatment is no longer appropriate.

Exchange fluctuation theorems for strongly interacting quantum pumps

We derive a general quantum exchange fluctuation theorem for multipartite systems with arbitrary coupling strengths by taking into account the informational contribution of the back-action of the quantum measurements, which contributes to the increase in the von-Neumann entropy of the quantum system. The resulting second law of thermodynamics is tighter than the conventional Clausius inequality. The derived bound is the quantum mutual information of the conditional thermal state, which is a thermal state conditioned on the initial energy measurement. These results elucidate the role of quantum correlations in the heat exchange between multiple subsystems.

Foreign exchange fluctuations on the performance of agricultural export in Nigeria

The study examines the effect of foreign exchange fluctuation on the performance of agricultural export in Nigeria. Despite the emphasis place on foreign exchange, the agricultural export in Nigeria is still not performing well. Time frame was from 1986 to 2021 and the adopted research design was ex post facto, in which the tool of analysis employed was the ARDL, ECM method, co-integration and unit root test as finding revealed that foreign exchange fluctuation on the performance of agricultural volume and value added has negative and insignificant effect in Nigeria. While foreign exchange fluctuation on the performance of agricultural capacity utilization has a positive and significant impact. Giving this finding, recommendations are that Nigerian government should moderate and regulate the rate of exchange activities in order to make certain that it brings about better performance in the agricultural sector. Also, she should strongly attempt to make better the stand of the economy internationally with other nations of the world in order to expand the market for Nigerian agricultural exports. Finally, the government should change the focus of its policy in direction to the external agricultural sector and making sure that it adds in the most favourably way to output performance. As an intentional policy, the government should give support to rural area agriculture by which investors in distinct communities and commodities should be encourage to set up agricultural industries, which will be solely on local raw materials comprising equipment and machines.

Consequences to the Stock Market Caused by Currency Fluctuations: Jordanian Evidence

Purpose: The aim of this study is to examine the fluctuations in currency exchange in the stock market, as it relates to the Jordanian market. Theoretical framework: The study's main goal is to identify how Jordanian SMR changes in currency exchange are influenced. Thus, the rational expectations theory has been used in this study. This theory illustrates three key aspects that influence the decision to participate in the stock market, including the availability of information, prior experience, and human reason. Design/ methodology/approach: The study incorporates the quantitative design, in which, information was extracted from secondary sources i.e. Investing.com. The information has been compiled considering the exchange rates, stock market returns, and cotton prices, beginning in 2015 and ending in 2020. The analysis has been conducted with Granger Causality test, VAR, and ADF. Findings: The results of this study concludes that fluctuations of exchange rates do not impact changes in cotton prices and the returns of the Jordanian stock exchange. Research, Practical & Social implications: The study is limited to Jordan, as only Jordan’s cotton price and stock market return data have been gathered. In addition, the time period of consideration of data is confined from 2015 to 2019, limiting the study’s scope. Originality/Value: The study uses sensitivity analysis to investigate the robustness of the impacts of fluctuations in currency exchange in the stock market, as it relates to the Jordanian market.