External Fluctuations Research Articles

Metagenomic insights into microalgae-bacterium-virus interactions and viral functions in phycosphere facing environmental fluctuations

Despite the ecological and biotechnological significance of microalgae-bacterium symbionts, the response of host-virus interactions to external environmental fluctuations and the role of viruses in phycosphere remain largely unexplored. Herein, we employed algal-bacterial granular sludge (ABGS) with varying light intensity and organic carbon loading to investigate the mechanisms of microalgae-bacterium-virus symbionts in response to environmental fluctuations. Metagenomics revealed that enhanced light intensity decreased the diversity of microalgae, so did the diversity of symbiotic bacteria and viruses. As carbon sources decreased, bacteria prompted horizontal gene transfer in phycosphere by 12.76 %-157.40 %, increased the proportion of oligotrophs as keystone species (0.00 % vs 14.29 %) as well as viruses using oligotrophs as hosts (18.52 % vs 25.00 %). Furthermore, virus-carried auxiliary metabolic genes (AMGs) and biosynthetic gene clusters (BGCs) encoding vitamin B12 synthesis (e.g., cobS), antioxidation (e.g., queC), and microbial aggregation (e.g., cysE). Additionally, phylogenetic and similarity analysis further revealed the evolutionary origin and potential horizontal transfer of the AMGs and BGCs, which could potentially enhance the adaptability of bacteria and eukaryotic microalgae. Overall, our research demonstrates that environmental fluctuations have cascading effects on the microalgae-bacteria-virus interactions, and emphasizes the important role of viruses in maintaining the stability of the phycosphere symbiotic community.

Domestic inflation decomposition in a small open economy: Evidence from import price dynamics in Kazakhstan

This paper empirically analyzes the key drivers of inflation in Kazakhstan by differentiating between demand and supply-driven factors contributing to headline inflation. Given that Kazakhstan is highly sensitive to adverse external fluctuations (due to its economic structure), our empirical strategy investigates asymmetric dynamics of prices of goods with high versus low degree of import share. Hence, we develop a methodology to determine the level of “importability” in certain consumption products, which serves as a proxy of vulnerability to external macroeconomic shocks. The results confirm our hypothesis that products with different degree of import content respond differently to major macroeconomic shocks. Consequently, we conclude that headline inflation in Kazakhstan is primarily impacted by supply-side factors, such as the direct transmission of exchange rate changes to prices of products with higher import shares (exchange rate pass-through) and a large component of inflation inertia. Differentiating and properly identifying inflation dynamics of the high-import-content and low-import-content goods have important implications for optimal monetary policy conduct in developing economies.

Engineering Rydberg-pair interactions in divalent atoms with hyperfine-split ionization thresholds

Quantum information processing with neutral atoms relies on Rydberg excitation for entanglement generation. While the use of heavy divalent or open-shell elements, such as strontium or ytterbium, has benefits due to their optically active core and a variety of possible qubit encodings, their Rydberg structure is generally complex. For some isotopes in particular, hyperfine interactions are relevant even for highly excited electronic states. We employ multichannel quantum defect theory to infer the Rydberg structure of isotopes with nonzero nuclear spin and perform nonperturbative Rydberg-pair interaction calculations. We find that due to the high level density and sensitivities to external fields, experimental parameters must be precisely controlled. Specifically in Sr87, we study an intrinsic Förster resonance, unique to divalent atoms with hyperfine-split thresholds, which simultaneously provides line stability with respect to external field fluctuations and enhanced long-range interactions. Additionally, we provide parameters for pair states that can be effectively described by single-channel Rydberg series. The explored pair states provide exciting opportunities for applications in the blockade regime, as well as for more exotic long-range interactions such as largely flat, distance-independent potentials. Published by the American Physical Society 2024

Optimizing Ship Draft Observation with Wave Energy Attenuation and PaddlePaddle-OCR in an Anti-Fluctuation Device

With the development and application of artificial intelligence (AI) in the shipping industry, using AI to replace traditional draft survey methods in bulk carriers can significantly reduce manpower, lower the risks associated with visual observations, improve measurement accuracy, and minimize the impact of human subjective factors. Ultimately, the integration of software and hardware technologies will replace human visual observations with automated draft measurement calculations. A similar anti-fluctuation device described in this article has been used in ship draft observation based on AI-assisted proving, which can ease the fluctuation of the wave inside the pipe. Observers can directly read the water surface inside the pipe and compare it to the ship’s draft mark to obtain the final draft, effectively improving draft observation accuracy. However, some surveyors refuse to accept the readings obtained from this device, citing a lack of theoretical basis or the absence of accreditation from relevant technical authorities, leading to the rejection of results. To address these issues, this paper integrates wave energy attenuation theory with PaddlePaddle-OCR recognition to further validate the anti-fluctuation device for accurate ship draft observation. The experimental results are as follows: first, the pipe effectively suppresses the amplitude of external water surface fluctuations by 75%, explaining the fundamental theory that wave heights within the anti-fluctuation device are consistent with external swell heights. When taking a draft measurement, the system dynamically adjusts the position of the main tube in response to the ship’s movements, maintaining the stability of the measurement section and significantly reducing the difficulty of observations. Due to the reduction in fluctuation amplitude, there is a noticeable improvement in observation accuracy.

Better safe than sorry? The effect of asymmetric cost management on firm resilience in manufacturing firms

PurposeGlobal business practices show that during periods of demand volatility, manufacturing firms often engage in asymmetric cost management (ACM), a behavior in which costs increase faster than they decrease when demand decreases by the same amount. However, whether managing asymmetric costs will enhance or impede firm resilience remains an open question. We aim to investigate the impact of ACM on firm resilience and its boundary conditions.Design/methodology/approachUsing unbalanced panel data of 2,273 Chinese manufacturing listed companies from 2002 to 2021, we conduct an empirical analysis using a double fixed effects model.FindingsOur findings reveal that ACM has a negative effect on firm resilience. This suggests that in coping with external environmental fluctuations, ACM fails to fulfill its expected role effectively. Instead, it manifests as a severe agency problem affecting firm resilience. Further, we find that managerial myopia and digitalization diminish the negative effect, while customer instability exacerbates it.Originality/valueThis study contributes to the literature on the organizational resilience of manufacturing firms by providing an in-depth understanding of cost management and emphasizing the need to consider agency issues carefully when managing asymmetric costs.

Role of Polyhouse Technology in Mitigating Climate Risks for Floriculture

Climate change poses significant challenges to agricultural productivity, particularly in sectors like floriculture that rely heavily on favorable environmental conditions. In this context, polyhouse technology emerges as a promising solution for mitigating climate risks faced by floriculture farmers. Polyhouses provide a controlled environment that shields crops from extreme weather events, temperature fluctuations, and excessive rainfall, thereby reducing the vulnerability of floriculture production to climate variability. This paper reviews the role of polyhouse technology in climate risk mitigation for floriculture farmers. It examines how polyhouses help in maintaining optimal growing conditions, including temperature, humidity, and light intensity, throughout the year. By regulating these environmental factors, polyhouses enable year-round cultivation of high-value flower crops, offering farmers a stable income stream despite external climate fluctuations. Furthermore, the study explores the economic and environmental benefits associated with polyhouse-based floriculture systems. It analyses the cost-effectiveness of polyhouse construction and operation, considering factors such as energy consumption, water usage, and crop yield. Additionally, the environmental sustainability of polyhouse technology, including its potential to reduce pesticide and fertilizer usage, is discussed. The paper also highlights the challenges and limitations of adopting polyhouse technology in floriculture farming, including initial investment costs, technical expertise requirements, and market access issues. Strategies for overcoming these barriers, such as government subsidies, capacity building programs, and market linkages, are proposed. The polyhouse technology can play a climate-resilient solution for floriculture farmers, offering opportunities for increased productivity, income stability, and environmental sustainability in the face of climate change.

Dynamic Double Event-Triggered Anti-Disturbance Tracking Control for a 2-DOF Small Unmanned Helicopter.

This article devises a new dynamic double event-triggered anti-disturbance tracking control scheme for a 2-degree of freedom (DOF) laboratory helicopter subject to external time-varying disturbances and load fluctuation by using the generalized proportional-integral observer technique. The helicopter system is separated into two subsystems in the proposed control method, i.e., the pitch subsystem and the yaw subsystem. Each subsystem includes a discrete-time dynamic double event-triggering mechanism (DDETM), and the control laws of the two subsystems are independent of each other. There are two triggering conditions in the designed double triggering mechanism: one is designed based on the system states and the other is based on the lumped disturbance estimation. These two triggering conditions form a competitive relationship such that the controller updates the control signal as long as one of the triggering conditions is satisfied. Theoretical analysis is provided for achieving the better communication and control performance of the proposed DDETM-based robust control method. Through rigorous stability analysis, it is proved that the closed-loop hybrid system is globally ultimately bounded. At last, numerical simulations show that the suggested control strategy not only reduces the event-triggering number, but also improves the initial dynamic performance of the system.

Fluctuation-driven dynamics of liquid nano-threads with external hydrodynamic perturbations

Instability and rupture dynamics of a liquid nano-thread, subjected to external hydrodynamic perturbations, are captured by a stochastic lubrication equation (SLE) incorporating thermal fluctuations via Gaussian white noise. Linear instability analysis of the SLE is conducted to derive the spectra and distribution functions of thermal capillary waves influenced by external perturbations and thermal fluctuations. The SLE is also solved numerically using a second-order finite difference method with a correlated noise model. Both theoretical and numerical solutions, validated through molecular dynamics, indicate that surface tension forces due to specific external perturbations overcome the random effects of thermal fluctuations, determining both the thermal capillary waves and the evolution of perturbation growth. The results also show two distinct regimes: (i) the hydrodynamic regime, where external perturbations dominate, leading to uniform ruptures, and (ii) the thermal-fluctuation regime, where external perturbations are surpassed by thermal fluctuations, resulting in non-uniform ruptures. The transition between these regimes, modelled by a criterion developed from linear instability theory, exhibits a strong dependence on the amplitudes and wavenumbers of the external perturbations.

Robust control based on type-2 fuzzy logic for permanent magnet synchronous motor (PMSM)

This paper introduces a novel control technique utilizing the orientation of stator flux based on type 2 fuzzy controllers to control the mechanical power generated by a permanent magnet synchronous motor and addressing parametric variation challenges to enhance robust performance against external fluctuations. The Permanent Magnet Synchronous Motors driven by stator variables via two converters relies on these components to interface with the electrical network in distinct manners. The network-side converter facilitates continuous bus control and enhances power factor, while the motor-side converter enables precise control and optimization of energy flow during motor operation. The paper outlines the motor and converter models, followed by the development of control commands to regulate mechanical power (speed, torque) for optimal efficiency and production quality and we will then present a comparative study between the developed controls to highlight the best performing and most robust of each, . Numerical simulations demonstrate the effectiveness of implementing type 2 fuzzy logic control in achieving these objectives.

Environmental and Human Impact on Ice Caves: The Example of the Wielka Śnieżna Cave in the Tatra Mountains (Poland)

Ice caves are characterised by specific microclimate, defined by the external climate as well as cave morphology (hence the location). They are unique components of Earth’s heritage. The ice formed there holds important paleoclimatic information and can be used to assess the global warming effect on the cryosphere in non-glaciated areas. We present an example from Wielka Śnieżna, the deepest cave system in the Polish Tatra Mountains, located in Tatra National Park (Tatrzański Park Narodowy). There have been no recent studies completed on the topic in this location. We provide the first contemporary results of temperature measurements by analysing microclimatic patterns and their response to global warming. There is ongoing ablation of the Ice Fall located in one of the lower entrances (Śnieżna) showing that the ice level has decreased by around 2 m in the last 10 years. The cave is under a minor human impact as it can be accessed only by professional cavers. However, some practices impact the balance of this fragile environment. By comparing our results with the outside temperature records, we aim to understand how dependent the cave microclimate is on the external fluctuations and changes. The ice in the Śnieżna is expected to be gone in the current century.

Fluctuations and Power Low Distribution Function in Nonequilibrium Systems

The Fokker–Planck equation is formulated for the distribution functions of macroscopic open systems in the space of slowly changing physical variables (energy, adiabatic invariants, etc.). The stationary solution of such equations determines a quasi-equilibrium distribution function in the relevant space. The proposed approach involves the evolution of systems under the action of dissipation and diffusion in the space of the appropriate variables. It is shown that the well-known power law distribution can be obtained by considering internal and external fluctuations in statistical systems.

Effect of Cell-to-Cell Internal Resistance Variations on the Thermal Performance of Lithium-Ion Batteries for Urban Air Mobility

This study examines the thermal behavior of lithium-ion battery modules intended for Urban Air Mobility (UAM), a forthcoming urban transport system designed to facilitate efficient and secure passenger and cargo transport within city centers. UAM applications necessitate batteries with high energy densities capable of sustaining elevated discharge rates during critical phases such as takeoff and landing. The battery module evaluated in this study comprises four cells arranged in series and configured as a submodule for UAM applications. A three-dimensional thermal model was utilized to analyze the impact of external temperature fluctuations and high discharge rates on the performance of the battery module. The numerical findings indicated considerable variations in temperature and internal resistance among the cells, especially under high discharge rates at low temperatures, with a maximum temperature deviation of 32.952 °C observed at an 8 C discharge rate. These thermal non-uniformities were attributed to variations in cell capacity and internal resistance, which were amplified by manufacturing inconsistencies and operational conditions. The study underscores the necessity of robust thermal management strategies to mitigate the risk of thermal runaway and ensure the operational safety and reliability of UAM systems. The results emphasize the critical role of advanced Battery Management Systems (BMS) in monitoring and controlling cell voltage and temperature to achieve consistent performance across the battery module. This research contributes valuable insights into the design of more efficient and reliable battery modules for UAM, highlighting the importance of addressing cell-to-cell performance discrepancies to enhance overall module efficacy and durability.

Impacto macroeconómico de la dolarización en el Ecuador durante el período 2006-2023

The macroeconomic impact is crucial for determining the well-being of a country. Analyzing variables such as Gross Domestic Product (GDP), inflation, unemployment, investment, and foreign trade allows for an assessment of a nation's economic health and financial stability. This article aims to analyze the impact of dollarization in Ecuador between 2006 and 2023. Adopted in 2000 to stabilize the economy and attract foreign investment; dollarization presented monetary and fiscal policy challenges. Authors like Cachanosky and Alvarado highlight the challenges in fiscal control and the relationship between exports and external income. The study employs a quantitative methodology, with regression analysis and time series based on data from the Central Bank of Ecuador. The results show moderate GDP growth and gross investment, as well as fluctuations in liquidity and credit to the private sector, along with persistent inequality in income distribution. The conclusions indicate that while dollarization has contributed to stability, it has limited the country's monetary autonomy. Additionally, dependence on external factors, such as U.S. monetary policy, has affected Ecuador's economic stability. The importance of diversifying the economy, promoting policies that foster sustainable and equitable growth, and reducing vulnerability to external fluctuations is emphasized.

Long-term stability of squeezed light in a fiber-based system using automated alignment.

Providing a cloud service for optical quantum computing requires stabilizing the optical system for extended periods. It is advantageous to construct a fiber-based system, which does not require spatial alignment. However, fiber-based systems are instead subject to fiber-specific instabilities. For instance, there are phase drifts due to ambient temperature changes and external disturbances and polarization fluctuations due to the finite polarization extinction ratio of fiber components. Here, we report the success of measuring squeezed light with a fiber system for 24h. To do this, we introduce stabilization mechanics to suppress fluctuations in the fiber system and an integrated controller to automatically align the entire system. The squeezed light at a wavelength of 1545.3nm is measured every 2min, where automated alignments are inserted every 30min. The squeezing levels with an average of -4.42 dB are recorded with an extremely small standard deviation of 0.08 dB over 24h. With the technologies developed here, we can build complicated optical setups with the fiber-based system and operate them automatically for extended periods, which is promising for cloud service of quantum computation.

Study on the control effectiveness of relative humidity by various ventilation systems for the conservation of cultural relics

The Dadiwan F901 site, boasting a history of over 5000 years, stands as the largest and most intricately crafted large-scale housing structure from China’s prehistoric era. The early renovation efforts, incorporating a sealed glass curtain wall, led to a continuous rise in relative humidity within the site, triggering outbreaks of microbial diseases. Subsequent measures successfully restored stability to the thermal and humid environment. This paper employs on-site real-time environmental monitoring and numerical simulation methods to assess the ventilation effectiveness and relative humidity changes before and after multiple interior modifications of the Dadiwan F901 site museum. The results indicate that the fully enclosed glass curtain wall can suppress the dependence of indoor humidity fluctuations on external weather fluctuations but has generated unintended consequences, leading to increased air relative humidity and even reaching saturation in the museum space. The strategic deployment of louvered windows and duct fans proved effective in enhancing internal airflow dynamics and overall air exchange capacity. It was possible to ensure that the relative humidity inside the site remained at approximately 70%, meeting the essential requirements for the preservation of cultural relics. This study is of great significance for alleviating the deterioration problem of enclosed exhibition halls of earthen relics.Graphical

An optimisation method for planning and operating nearshore island power and natural gas energy systems

As the development and use of offshore islands increase, so do the diversity of their energy needs, the cost of utilising the mainland for resource replenishment, and the instability of island energy systems. To address this challenge, this paper introduces an innovative system integrating fossil and renewable energy tailored for these islands, considering seasonal variations and external energy fluctuations. Leveraging a P-graph, an optimisation framework is designed to assess different optimised solutions. A comprehensive analysis is also performed to compare the solutions, while sensitivity assessments evaluate factors including electricity and gas price fluctuations, renewable energy availability, and natural gas demand. Additionally, the carbon emissions resulting from different power generation scenarios are visually represented and thoroughly analysed. The results support two key findings: 1) the cost of combined energy supply is lowest when wind energy accounts for 59 % of the total energy, mainland grid connection accounts for 3 %, fossil fuel energy accounts for 28 %, and natural gas accounts for 10 % of the energy mix; and 2) the price of electricity and natural gas supplied to the islands and the variability in the energy sources of wind and natural gas can significantly affect the cost of the energy system.

Intensity noise reduction in quantum dot comb laser by lower external carrier fluctuations.

This work investigates the impact of carrier noise induced by an external current source on the linewidth enhancement factor (LEF) and relative intensity noise (RIN) of a 100 GHz quantum dot fourth-order colliding-pulse mode-locked laser (MLL), driven by a normal pump with Gaussian-distributed carrier sequences and a quiet pump with sub-Poissonian-distributed carrier sequences. The results indicate that under a normal pump, the LEFs are approximately zero for reverse saturable absorber (SA) bias voltages ranging from 0 to 2.5 V, and the laser achieves a RIN as low as -156 dB/Hz. When using a quiet pump, both the LEF and RIN are reduced across all SA bias conditions, particularly at low reverse SA bias voltages. Specifically, the LEF decreases by up to 0.58 at 0 V, and the average RIN spectrum is reduced by more than 3 dB at the same voltage. This work provides a straightforward approach for the development and optimization of multi-channel light sources for dense wavelength division multiplexing (DWDM) technologies with low optical noise.

Thermal resilience of buildings: The role of partition walls and slabs in the optimization of the building external envelope

Nowadays it is advisable for buildings to be thermally resilient, so as to passively resist to the daily external air temperature fluctuations, reducing the interventions of air conditioning systems to a minimum. The decrement factor and time lag are parameters notoriously used to evaluate the responses of the building envelope to periodic oscillations in external air temperature. However, in their traditional definition, these parameters do not consider the effects of internal elements, such as partition walls and slabs, which instead influence the passive thermal behaviour of the building. For this reason, a choice of the external wall stratigraphy, made exclusively on the basis of the traditional decrement factor and time lag, seems to be simplistic. In this paper, problems concerning the passive behaviour of buildings, in case of sinusoidal outdoor air temperature variations, are investigated. Within a lumped-capacitance scheme and using the heat transfer matrix method, the problem of the determination of a wall stratigraphy minimizing the decrement factor for given values of the overall thermal resistance and capacity, usable for the realization of both external and internal walls of a given room, is solved. After developing an analysis on the influence of the internal walls and slabs on the room thermal balance, the resistance-capacity distribution, within the external wall, minimizing the decrement factor is determined, for assigned thermal resistances and capacities of internal elements and the external wall. Results indicate that there is no resistance-capacity distribution that is absolutely better than the others, but it is dependent on the thermo-physical characteristics of the internal elements. The optimized external wall stratigraphy can be composed of an even number of resistive and capacitive layers, alternating with each other, or of an odd number of layers (with one more resistive layer than the capacitive ones). Even the number of layers that makes optimized the passive behaviour of the external wall varies with the characteristics of the internal elements, the results show that already with a number of layers varying from 2 to 5 high performances can be obtained.

Islamic Bank Performance and Macroeconomic Variables During Economic Turbulence

The study aims to analyze the effect of internal and external bank factors on the financial performance of Islamic banks during the Covid-19 pandemic. The external factors or macroeconomic factors consist of BI Rate and Inflation. The internal bank factors used are BOPO (Operating Expenses for Operating Income), CAR (Capital Adequacy Ratio), FDR (Financing to Deposit Ratio), NPF (Non-Performing Financing), and ROA (Return on Assets). A quantitative analysis is applied to assess the research construct by using a panel regression approach. The data used is sourced from Bank Indonesia and the Financial Services Authority for the observation period from 2019 - 2021. The findings show that external factors do not affect ROA in the long run and short run. Meanwhile, the internal factors BOPO and CAR significantly influence ROA, and NPF is having a significant impact only in the long run. The implications of this study show that Islamic banks need to strengthen operational efficiency, maintain capital adequacy, and implement good credit risk management in order to increase profitability sustainably, regardless of external fluctuations such as BI interest rates and inflation.

Study on Current Behavior and Thermal Stability of No-Insulation Coils With Parallel HTS Tapes Under External Magnetic Field Fluctuation

Study on Current Behavior and Thermal Stability of No-Insulation Coils With Parallel HTS Tapes Under External Magnetic Field Fluctuation