Complex Variables Research Articles

URBAN DESIGN QUALITIES OF EMBONG MALANG CORRIDOR, SURABAYA CITY

The Embong Malang Corridor is located between Kedungdoro District and Genteng District, Surabaya City. Jalan Embong Malang is a secondary arterial road that has strategic significance in the context of city development where this corridor features several commercial buildings on both sides of the road. Pedestrian paths on the Jalan Embong Malang Corridor are available along the north and south sides, becoming a vital means for people visiting the Embong Malang Corridor to move between buildings. However, there are problems related to the qualities of the urban design in this corridor, which directly impacts the walkability and functionality of the pedestrian path for pedestrians. This research aims to find out the condition of urban design qualities in the Embong Malang Corridor. This research method uses observations made to evaluate the existing condition of the corridor, relying on descriptive analysis to explain various related aspects. The results of the analysis show that there are still deficiencies in several aspects of urban design qualities, especially in the enclosure, complexity, and coherence variables. This evaluation provides important insights into corridor improvement and development efforts and encourages further attention to aspects of urban design to create a more pedestrian-friendly environment.

On the Applicability of Kramers–Kronig Dispersion Relations to Guided and Surface Waves

In unbounded media, the acoustic attenuation as function of frequency is related to the frequency-dependent sound velocity (dispersion) via Kramers–Kronig dispersion relations. These relations are fundamentally important for better understanding of the nature of attenuation and dispersion and as a tool in physical acoustics measurements, where they can be used for control purposes. However, physical acoustic measurements are frequently carried out not in unbounded media but in acoustic waveguides, e.g., inside liquid-filled pipes. Surface acoustic waves are also often used for physical acoustics measurements. In the present work, the applicability of Kramers–Kronig relations to guided and surface waves is investigated using the approach based on the theory of functions of complex variables. It is demonstrated that Kramers–Kronig relations have limited applicability to guided and surface waves. In particular, they are not applicable to waves propagating in waveguides characterised by the possibility of wave energy leakage from the waveguides into the surrounding medium. For waveguides without leakages, e.g., those formed by rigid walls, Kramers–Kronig relations remain valid for both ideal and viscous liquids. Examples of numerical calculations of wave dispersion and attenuation using Kramers–Kronig relations, where applicable, are presented for unbounded media and for waveguides formed by two rigid walls.

Expert system as a tool for management of thermal comfort in heat environments in agribusiness

This study evaluated the environmental conditions of various microenvironments in an urbanized rural area, focusing on the analysis of the Kawamura's Discomfort Index (DIK) and the application of a mathematical model based on fuzzy logic to determine human well-being (HWB). Data were collected at the Federal University of Grande Dourados (UFGD), Dourados-MS, Brazil, during the summer of 2023-2024, in five different microenvironments: no shading with asphalt floor, no shading with grass floor, no shading with concrete floor, tree cover with grassy floor, and tree cover with asphalt floor. Temperature and relative humidity were recorded to calculate DIK and evaluate environmental comfort levels in each location. A mathematical model based on fuzzy logic was also built to see its efficiency in representing real scenarios. In this model, the input variables were DIK and type of land cover, and the output variable was HWB. The results indicated that paved areas without shading presented the highest levels of thermal stress, while areas with greater vegetation cover showed better thermal comfort conditions. The fuzzy model developed proved to be an effective tool for representing levels of human well-being as a function of DIK and the type of land cover, allowing an accurate simulation of environmental scenarios. This research contributes to academia by interacting fuzzy logic with complex variables to accurately study human thermal comfort. Through this study, it was possible to suggest that urban planning policies should prioritize the maintenance and incorporation of vegetation, especially the presence of trees, to promote more comfortable and sustainable environments.

Force Fluctuations During Role-Differentiated Bimanual Movements Reflect Cognitive Impairments in Older Adults: A Cohort Sequential Study.

During role-differentiated bimanual movements (RDBM), an object is typically stabilized with 1 hand and manipulated with the other. RDBM require coupling both hands for coordinated action (achieved through interhemispheric connections), but also inhibition of crosstalk to avoid involuntary movements in the stabilizing hand. We investigated how healthy cognitive aging and mild cognitive impairments (MCI) affect force stabilization during an RDBM in a cohort sequential study design with up to 4 measurement points over 32 months. In total, 132 older adults (>80 years) participated in this study, 77 were cognitively healthy individuals (CHI) and 55 presented with MCI. Participants performed a visuomotor bimanual force-tracking task. They either produced a constant force with both hands (bimanual constant) or a constant force with 1 and an alternating force with the other hand (role-differentiated). We investigated force fluctuations of constant force production using the coefficient of variation (CV), detrended fluctuation analysis (DFA), and sample entropy (SEn). Results showed higher CV and less complex variability structure (higher DFA and lower SEn) during the role-differentiated compared to the bimanual constant task. Furthermore, CHI displayed a more complex variability structure during the bimanual constant, but a less complex structure during the role-differentiated task than MCI. Interestingly, this complexity reduction was more pronounced in CHI than MCI individuals, suggesting different changes in the control mechanisms. Although understanding these changes requires further research, potential causes might be structural deteriorations leading to less efficient (intra- and interhemispheric) networks because of MCI, or an inability to appropriately divert the focus of attention.

From Networking to Attitudinal Outcomes: Psychological Capital as a Mediator.

Building on conservation of resources (COR) theory and following recent recommendations, this study investigates the mediating role of Psychological Capital (PsyCap) in the relationships between networking behaviors and attitudinal outcomes (i.e., work engagement and work satisfaction). We propose that networking, as an investment of personal resources to gain access to other resources, contributes to the prediction of attitudinal outcomes. We surveyed 254 employees from a public Belgian administrative company. We use structural equation modelling and the bootstrapping method. PsyCap totally mediates the relationships between networking and both attitudinal outcomes. This study contributes to theoretical development by integrating Networking and PsyCap literatures into COR theory literature, and demonstrates the legitimacy of COR theory to explain these complex variables and their relationships.

The global patient-reported outcomes for multiple sclerosis initiative: bridging the gap between clinical research and care - updates at the 2023 plenary event.

Significant advancements have been achieved in delineating the progress of the Global PROMS (PROMS) Initiative. The PROMS Initiative, a collaborative endeavor by the European Charcot Foundation and the Multiple Sclerosis International Federation, strives to amplify the influence of patient input on MS care and establish a cohesive perspective on Patient-Reported Outcomes (PROs) for diverse stakeholders. This initiative has established an expansive, participatory governance framework launching four dedicated working groups that have made substantive contributions to research, clinical management, eHealth, and healthcare system reform. The initiative prioritizes the global integration of patient (For the purposes of the Global PROMS Initiative, the term "patient" refers to the people with the disease (aka People with Multiple Sclerosis - pwMS): any individual with lived experience of the disease. People affected by the disease/Multiple Sclerosis: any individual or group that is affected by the disease: E.g., family members, caregivers will be also engaged as the other stakeholders in the initiative). insights into the management of MS care. It merges subjective PROs with objective clinical metrics, thereby addressing the complex variability of disease presentation and progression. Following the completion of its second phase, the initiative aims to help increasing the uptake of eHealth tools and passive PROs within research and clinical settings, affirming its unwavering dedication to the progressive refinement of MS care. Looking forward, the initiative is poised to continue enhancing global surveys, rethinking to the relevant statistical approaches in clinical trials, and cultivating a unified stance among 'industry', regulatory bodies and health policy making regarding the application of PROs in MS healthcare strategies.

On solutions of certain compatible systems of quadratic trinomial Partial differential-difference equations

This paper has involved the use of a variety of variations of the Fermat-type equation $f^n(z)+g^n(z)=1$, where $n(\geq 2)\in\mathbb{N}$. Many researchers have demonstrated a keen interest to investigate the Fermat-type equations for entire and meromorphic solutions of several complex variables over the past two decades. Researchers utilize the Nevanlinna theory as the key tool for their investigations. Throughout the paper, we call the pair $(f,g)$ as a finite order entire solution for the Fermat-type compatible system $\begin{cases} f^{m_1}+g^{n_1}=1;\\ f^{m_2}+g^{n_2}=1,\end{cases}$\!\! if $f$, $g$ are finite order entire functions satisfying the system, where $m_1,m_2,n_1,n_2\in\mathbb{N}\setminus\{1\} .$\ Taking into the account the idea of the quadratic trinomial equations, a new system of quadratic trinomial equations has been constructed as follows: $\begin{cases} f^{m_1}+2\alpha f g+g^{n_1}=1;\\ f^{m_2}+2\alpha f g+g^{n_2}=1,\end{cases}$ \!\! where $\alpha\in\mathbb{C}\setminus\{0,\pm1\}.$ In this paper, we consider some earlier systems of certain Fermat-type partial differential-difference equations on $\mathbb{C}^2$, especially, those of Xu {\it{et al.}} (Entire solutions for several systems of nonlinear difference and partial differential-difference equations of Fermat-type, J. Math. Anal. Appl. 483(2), 2020) and then construct some systems of certain quadratic trinomial partial differential-difference equations with arbitrary coefficients. Our objective is to investigate the forms of the finite order transcendental entire functions of several complex variables satisfying the systems of certain quadratic trinomial partial differential-difference equations on $\mathbb{C}^n$. These results will extend the further study of this direction.

Skillful seasonal prediction of Afro-Asian summer monsoon precipitation with a merged machine learning and large ensemble approach

Afro-Asian summer monsoon precipitation (AfroASMP) is the life blood of billions of people living in many developing countries covering West Africa and Asia. Its complex variabilities are always accompanied by natural disasters like floods, landslides and droughts. Reliable AfroASMP prediction several months in advance is valuable for not only decision-makers but also regional socioeconomic sustainability. To address the current predicament of the AfroASMP seasonal prediction, this study provides an effective machine-learning model (Y-model). Y-model uses the monsoon related big climate data for searching the potential predictors, encompassing atmospheric internal factors and external forcings. Only the predictors associated with significant anomalies in summer horizonal winds at 850 hPa over the monsoon domain are retained. These selected predictors are then reorganized into a large ensemble based upon different thresholds of four fundamental principles. These principles include the focused sample sizes, the relationships between predictors and predictand, the independence among predictors, and the extremities of predictors in the forecast year. Real-time predictions can be generated based on the ensemble mean of skillful members during an independent hindcast period. Y-model skillfully predicts four monsoon precipitation indices of AfroASMP during 2011–2022 at lead 4–12 months, correlation skills range from 0.58 to 0.90 and root mean square error skills are reduced by 11–53% compared to CFS v2 model at lead 1 month. This study offers an effective method for preprocessing predictors in seasonal climate prediction.

HR 10 as seen by CHEOPS and TESS. Revealing delta Scuti pulsations, granulation-like signal and hint for transients

HR 10 has only recently been identified as a binary system. Previously thought to be an A-type shell star, it appears that both components are fast-rotating A-type stars, each presenting a circumstellar envelope. Although showing complex photometric variability, spectroscopic observations of the metallic absorption lines reveal variation explained by the binarity, but not indicative of debris-disc inhomogeneities or sublimating exocomets. On the other hand, the properties of the two stars make them potential delta Scuti pulsators. The system has been observed in two sectors by the TESS satellite, and was the target of three observing visits by CHEOPS. Thanks to these new data, we aim to further characterise the stellar properties of the two components. In particular, we aim to decipher the extent to to which the photometric variability can be attributed to a stellar origin. In complement, we searched in the lightcurves for transient-type events that could reveal debris discs or exocomets. We analysed the photometric variability of both the TESS and CHEOPS datasets in detail. We first performed a frequency analysis to identify and list all the periodic signals that may be related to stellar oscillations or surface variability. The signals identified as resulting from the stellar variability were then removed from the lightcurves inorder to search for transient events in the residuals. We report the detection of delta Scuti pulsations in both the TESS and CHEOPS data, but we cannot definitively identify which of the components is the pulsating star. In both datasets, we find flicker noise with the characteristics of a stellar granulation signal. However, it remains difficult to firmly attribute it to actual stellar granulation from convection, given the very thin surface convective zones predicted for both stars. Finally, we report probable detection of transient events in the CHEOPS data, without clear evidence of their origin.

Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait

Abstract. Estuaries have strong physicochemical gradients that lead to complex variability and often high rates of biogeochemical processes, and they are also often impacted by humans. Yet, our understanding of estuarine biogeochemistry remains skewed towards temperate latitudes. We examined seasonal and spatial variability in dissolved organic matter (DOM) and nutrients along a partly eutrophic, agricultural–urban estuary system in Southeast Asia: the Johor River and the East Johor Strait. Dissolved organic carbon (DOC) and coloured DOM (CDOM) showed non-conservative mixing, indicating significant DOM inputs along the estuary. The CDOM spectral slopes and CDOM : DOC ratios suggest that terrigenous, soil-derived DOM dominates along the Johor River, while phytoplankton production and microbial recycling are important DOM sources in the Johor Strait. CDOM properties were not unambiguous source indicators in the eutrophic Johor Strait, which is likely due to heterotrophic CDOM production. Nitrate concentrations showed conservative mixing, while nitrite concentrations peaked at intermediate salinities of 10–25. Ammonium concentrations decreased with salinity in the Johor River but increased up to 50 µmol L−1 in the Johor Strait, often dominating the dissolved inorganic nitrogen (DIN) pool. Phosphate concentrations were low (<0.5 µmol L−1) throughout the Johor River but increased in the Johor Strait, where DIN : phosphate ratios were typically ≥ 16 : 1. This suggests that the Johor Strait may experience phosphorus limitation and that internal recycling is likely important for maintaining high nutrient concentrations in the Johor Strait. Overall, our results indicate that the Johor River and Johor Strait are clearly not part of the same estuarine mixing continuum and that nutrient recycling processes must be quantified to understand nutrient dynamics in the Johor Strait. Moreover, our results highlight the need for better techniques for DOM source tracing in eutrophic estuaries.

Dimensionless resolutions for heat flux decrement factor and time lag of the wall during cyclic variations in outdoor air temperature

The heat flux decrement factor (DF) and time lag (TL) are two vital indicators for assessing wall dynamic thermal performance. However, computing these indicators involves complex variables such as material thermal properties, wall thickness, and others. Therefore, exploring the inherent relation between these two indicators and the influencing parameters is an urgent problem for reducing building energy consumption. To this end, an analytical method based on the auxiliary function was employed to calculate the heat flux DF and TL of a single-layer wall. Then, the impact of the influencing factors on heat flux DF and TL were evaluated. The results showed that heat flux DF and TL are only determined by two dimensionless parameters: diffusion length and thermal efficiency coefficient. The heat flux DF decreases by at least 5 times as the diffusion length varies from 0 to 2. Besides, it is also affected by the diffusion length when the thermal efficiency coefficient (ε) is less than 5, and the smaller the ε, the smaller the heat flux DF. On the other hand, the heat flux TL increases linearly with the diffusion length initially but declines precipitously as the diffusion length approaches 6–7. When the diffusion length is the same, the heat flux TL slightly decreases as the thermal efficiency coefficient increases.

Exploring the Role and Variability of 3d Transition Metal Complexes in Artistic Coloration through a Bottom-Up Scientific Approach

Exploring the Role and Variability of 3d Transition Metal Complexes in Artistic Coloration through a Bottom-Up Scientific Approach

Analysis of trust factors for AI-assisted diagnosis in intelligent Healthcare: Personalized management strategies in chronic disease management

By utilizing various techniques to integrate the Unified Theory of Acceptance and Use of Technology (UTAUT) model with the variables of personal innovation and task complexity, an initial trust mechanism is established. Based on the inherent motivation and demand of doctors to use AI-assisted diagnosis systems, a doctor adoption model for AI-assisted diagnosis systems is established. Using chronic disease management as an example, personalized management strategies based on reinforcement learning technology are discussed for a virtual management environment that provides intervention recommendations according to the medical condition. It is shown in experiments that the fitting goodness-of-fit value of the model for willingness to use, which excludes initial trust-related factors, is only 0.557, while the fitting goodness-of-fit value of the proposed model in this paper is 0.673. This indicates that the model that includes initial trust factors can more accurately explain the logic of the behavior evolution of doctors adopting AI-assisted diagnosis systems.

New Trends in Complex Analysis Research

This Special Issue aims to present some of the newest results obtained from the study of complex-valued functions of one or several complex variables [...]

Complex hydrology and variability of nitrogen sources in a karst watershed.

Streams draining karst areas with rapid groundwater transit times may respond relatively quickly to nitrogen reduction strategies, but the complex hydrologic network of interconnected sinkholes and springs is challenging for determining the placement and effectiveness of management practices. This study aims to inform nitrogen reduction strategies in a representative agricultural karst setting of the Chesapeake Bay watershed (Fishing Creek watershed, Pennsylvania) with known elevated nitrate contamination and a previous documented groundwater residence time of less than a decade. During baseflow conditions, streamflow did not increase with drainage area. Headwaters and the main stem lost substantial flow to sinkholes until eventually discharging along large springs downstream. Seasonal hydrologic conditions shift the flow and nitrogen load spatially among losing and gaining stream sections. A compilation of nitrogen source inputs with the geochemistry and the pattern of enrichment of δ15N and δ18O suggest that the nitrogen in streams and springs during baseflow represents a mixture of manure, fertilizer, and wastewater sources with low potential for denitrification. The pH and calcite saturation index increased along generalized flow paths from headwaters to springs and indicate shorter groundwater residence times in baseflow during the spring versus summer. Given the substantial investment in management practices, fixed monitoring sites could incorporate synoptic water sampling to properly monitor long-term progress and help inform management actions in karst watersheds. Although karst watersheds have the potential to respond to nitrogen reduction strategies due to shorter groundwater residence times, high nitrogen inputs, effectiveness of conservation practices, and release of legacy nutrients within the karst cavities could confound progress of water quality goals.

P‐6: Redefining Pixel Circuit Analysis: Causal Discovery and Probabilistic Modeling

When analyzing data using existing machine learning models without explicit causal information, several limitations often arise, particularly in the misinterpretation of correlations as causal relationships. These limitations are more pronounced in complex scenarios or in situations where outcomes are influenced by sequential effects. This paper presents an advanced methodology for analyzing pixel circuit design and its driving conditions, a domain characterized by complex interactions and multiple variables. Traditional machine learning methods, when applied in isolation, have shown limitations in unraveling the intricate causal relationships inherent in such systems. To address this challenge, we integrated Explainable AI (XAI) techniques, particularly SHAP (SHapley Additive exPlanations) values, into our analysis. In collaboration with domain experts, we constructed a Directed Acyclic Graph (DAG) that effectively reduced the complexity of interconnections and ensured consistency with empirical data. This approach facilitated a more accurate identification of the impact of each parameter and its causal influence. By decomposing the joint distribution of the variables into conditional distributions, taking into account their parental relationships, we gained a deeper understanding of the changes in causal mechanisms. Our methodology significantly enhanced the accuracy of causal analysis under realistic pixel driving conditions. The findings not only offer novel insights into pixel circuitry but also demonstrate the efficacy of combining machine learning with XAI in complex systems analysis, gaining wide acceptability among relevant experts.

Three‐phase state estimation in transmission networks with unbalanced loading utilising SCADA measurements

AbstractState estimation stands as one of the most crucial applications in energy management systems of control centres, ensuring the secure operation of the power system. The real‐time availability of accurate system variables, including voltages, currents, and power flows, presents an excellent opportunity to consider the actual network characteristics, including imbalances. This paper presents a linear and non‐iterative method to solve the three‐phase state estimation problem in transmission systems with unbalanced loading. The method utilises supervisory control and data acquisition measurements obtained from remote terminal units. The formulation is based on complex variables derived from traditional supervisory control and data acquisition measurements, with assumptions made regarding the availability of certain three‐phase bus voltages, as well as a number of three‐phase currents and active and reactive power flows. The proposed algorithm employs the classical weighted least squares technique for solving the three‐phase state estimation problem. Due to its straightforward and linear nature, the method ensures no convergence issues. To validate its effectiveness, the proposed method is validated on a three‐bus network and the IEEE 39‐bus network simulated using the three‐phase model within the DIgSILENT Power Factory environment.

Factors Influencing English Communication Proficiency Development Among B40 Preschool Children in Tanjung Malim, Perak, Malaysia

This study examines the complex variables affecting B40 preschoolers' English communication skills in Tanjung Malim, Perak, Malaysia. The research is based on Malaysia's commitment to excellent education for everyone, especially underprivileged populations. The research goals are to identify and analyze these influential factors, examine B40 families' socioeconomic backgrounds, evaluate preschool quality and accessibility, examine parental involvement, and support, and examine peer interactions and classroom environments. A sample size of 100 respondents B40 preschoolers and their parents are surveyed using quantitative approaches, including a standardized questionnaire. Regression analysis is used to examine the relationships between Socio-economic Status, Preschool Education Quality, Parental Involvement and Support, and English Communication Proficiency Development. Socio-economic Status, Preschool Education Quality, and Parental Involvement and Support significantly affect English language competency in B40 preschool children, according to the research. The results add to the research on language development in Malaysian B40 communities and have implications for policymakers, educators, and stakeholders working to improve language education for vulnerable people. This study helps areas with comparable socioeconomic issues improve English language competency in B40 preschoolers to boost educational achievement and social mobility.

The Digital Divide, Wealth, and Inequality: An Examination of Socio-Economic Determinants of Collaborative Environmental Governance in Thailand through Provincial-Level Panel Data Analysis

Collaborative environmental governance (CEG) is a tripartite process that engages the government, private sector, and general public in decision-making related to environmental challenges, focusing on fostering more sustainable and efficient solutions. Understanding the specific factors influencing the degree of CEG presents a significant challenge, particularly in developing countries. This study aims to identify and assess the socio-economic determinants affecting the degree of CEG in Thailand, a representative developing country. Utilizing robust panel data models, which are well-suited to handle the complex variability of socio-economic factors, we analyzed provincial-level data from 2017 and 2019. Our findings revealed the associations between the degree of CEG and variables such as the internet access divide, economic activities, income inequality, and budget allocations for environmental activities. This research fills critical gaps in our understanding of how these determinants shape collaborative governance efforts, offering novel insights that challenge existing paradigms and providing actionable recommendations for policymakers striving to enhance environmental governance in developing regions.

Early biomarkers of disease in hypertrophic cardiomyopathy: does telomere length matter?

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Biomedical Research Institute of Murcia (IMIB-Arrixaca) Introduction Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden death in people under 35 years of age. (1) The variability of the phenotype together with its incomplete penetrance has been an obstacle to a complete understanding of the clinical spectrum and consequences of the disease. In recent years, there has been increasing interest in telomeric shortening and several authors have linked it to age-related diseases and HCM. (2, 3) Our aim was to study whether telomere length could affect the age at presentation and the severity of the HCM phenotype in genetic carriers. Methods Measurement of telomere length in circulating leukocytes (LTLc) was performed in 96 patients carrying a mutation in MYBPC3 causing HCM [58 affected (24 severely affected), 38 unaffected]. The variants included were c.2308+1G>A, p.Pro108Alafs*9, p.Arg891Alafs*160 and p.Glu258Lys, all considered founder mutations in our region. Peripheral venous blood samples were obtained from patients at the Inherited Heart Diseases Unit and stored at -80 ºC after informed consent had been signed by all participants. For telomere length analysis, a telomeric restriction fragment (TRF) assay was performed using the TeloTAGGGTelomereLenghtAssay kit (Roche, 12209136001) according to the manufacturer's protocol with slight modifications. Results Our results show a lower LTLc in those affected patients with a more severe HCM phenotype compared to the affected and unaffected group (p=0.023) independently of age and sex, which are two variables that affect LTLc. Similarly, a shorter telomere length was associated with greater severity of the phenotype, with patients presenting a larger left atrial size (p=0.032), septal size (p=0.023) and greater obstruction (p=0.044). The presence of atrial fibrillation (p=0.039) and sudden death (p=0.024) was also higher in patients with shorter telomeres. Conclusions Telomere length is a variable that influences the expression of the phenotype in HCM patients carrying a MYBPC3 variant. This is an observation that supports the thesis of numerous publications linking HCM and other age-related diseases, sometimes called telomeropathies,(2) to telomere shortening. It has also been linked to non-hereditary conditions(3). This fact sheds some light on the complex phenotypic variability present in HCM, raising LTL as a promising prognostic biomarker of the disease, as has already been suggested by other authors.(4, 5, 6).Workflow in the telomere legth analysisClinical associations of LTLc