Control Functions Research Articles

Algorithmic trading and mini flash crashes: Evidence from Austria

We use stock-day level data on the market share of algorithmic trading to analyze whether algorithmic trading affects the frequency of mini flash crashes in the Austrian stock market. We use an instrumental variables approach and the Petrin and Train (2010) control function approach to address endogeneity concerns. We find no evidence that algorithmic trading significantly affects the probability of the occurrence of mini flash crashes.

The Lifespan Trajectories of Brain Activities Related to Cognitive Control.

Cognitive control plays a pivotal role in guiding human goal-directed behavior. While existing studies have documented an inverted U-shaped trajectory of cognitive control both behaviorally and anatomically, little is known about the corresponding changes in functional brain activation with age. To bridge this gap, we conducted a comprehensive meta-analysis of 129 neuroimaging studies using conflict tasks, encompassing 3,388 participants aged from 5 to 85 years old. We have three major findings: 1) The inverted U-shaped trajectory is the predominant pattern; 2) Cognitive control-related brain regions exhibit heterogeneous lifespan trajectories: the frontoparietal control network follows inverted U-shaped trajectories, peaking between 24 and 40 years, while the dorsal attention network demonstrates no clear trajectories; 3) Both the youth and the elderly show weaker brain activities and greater left laterality than young to middle-aged adults. These results reveal the lifespan trajectories of cognitive control, highlighting heterogeneous fluctuations in brain networks with age.

Distinct Effects of Major Affective Disorder Diagnoses and Suicidal Symptom Severity on Inhibitory Control Function and Proinflammatory Cytokines: Single-Site Analysis of 800 Adolescents and Adults.

Inhibitory control function and proinflammatory cytokines play a role in the pathomechanisms underlying major affective disorders and suicidal behavior. However, the distinct or interactive effects of major affective disorders and suicidal symptom severity on inhibitory control function and proinflammatory cytokines remain unclear. This study included 287 patients with bipolar disorder, 344 with major depressive disorder, and 169 healthy controls. We categorized the participants into 3 groups based on Montgomery-Åsberg Depression Rating Scale (MADRS) item 10 (suicidal symptoms) score: 0, 2 or 3, and ≥4. The participants completed the go/no-go task and the measurements for C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) levels. Errors in the go/no-go task were associated with suicidality (P = .040), regardless of the severity of suicidal symptoms and diagnosis. An elevated CRP level was especially associated with a Montgomery-Åsberg Depression Rating Scale item 10 score ≥4 (P = .001). An increased TNF-α level could distinguish bipolar disorder from major depressive disorder (P < .001). Our study indicated the distinct effects of major affective disorder diagnosis and suicide symptom severity on inhibitory control function and CRP and TNF-α levels. Importantly, individuals with the poorest inhibitory control function and highest CRP levels had more severe suicidal symptoms.

Mechanisms for Control of the Executive by the Bundestag

One of the functions of the representative body, alongside the legislative function, is the control function. It is a very important element of parliamentary-cabinet rule, and the way it is carried out, the instruments of scrutiny and the possibility for opposition factions in particular to use them are one of the pillars of a democratic state. Among the control mechanisms found in German law, are, among others, discharge, committees of enquiry, big and small questions, and questions to the government. The wide range of scrutiny instruments and the procedural arrangements that allow opposition representatives to use them enable the Bundestag, committees and members of the legislature to exercise effective scrutiny of the federal government’s activities.

A Novel Estimating Algorithm of Critical Driving Parameters for Dual-Motor Electric Drive Tracked Vehicles Based on a Nonlinear Observer and an Adaptive Kalman Filter

High-speed dual-motor electric drive tracked vehicles (DDTVs) have emerged as a research hotspot in the field of tracked vehicles in recent years due to their advantages in fuel economy and the scalability of electrical equipment. The emergency braking of a DDTV at high speed can lead to slipping or even yawing (which is caused by a large deviation of forces at each track directly), posing significant challenges to the vehicle’s stability and safety. Therefore, the accurate real-time acquisition of critical driving parameters, such as the longitudinal force and vehicle speed, is crucial for the stability control of a DDTV. This paper developed a novel estimating algorithm of critical driving parameters for DDTVs equipped with conventional sensors such as rotary transformers at PMSMs and onboard accelerometers on the basis of their dynamics models. The algorithm includes a sensor signal preprocessing module, a longitudinal force estimation method based on a nonlinear observer, and a speed estimation method based on an adaptive Kalman filter. Through hardware-in-loop experiments based on a Speedgoat real-time target machine, the proposed algorithm is proven to estimate the longitudinal force of the track and vehicle speed accurately, whether the vehicle has stability control functions or not, providing a foundation for the further development of vehicle stability control algorithms.

Multifractal analysis of Hewitt-Stromberg measures with respect to gauge control functions

This study provides a general multifractal formalism that overcomes the limitations of the traditional one. The generic Hewitt-Stromberg measures are used to introduce and study a multifractal formalism. The generic Hewitt-Stromberg dimensions' upper and lower bounds are estimated, producing results even at places $q$ where the upper and lower multifractal Hewitt-Stromberg dimension functions diverge.

Characterization of BioID tagging systems in budding yeast and exploring the interactome of the Ccr4-Not complex.

The modified E. coli biotin ligase BirA* was the first developed for proximity labeling of proteins (BioID). However, it has low activity at temperatures below 37˚C, which reduces its effectiveness in organisms growing at lower temperatures, such as budding yeast. Multiple derivatives of the enzymes have been engineered, but a thorough comparison of these variations of biotin ligases and the development of versatile tools for conducting these experiments in Saccharomyces cerevisiae would benefit the community. Here, we designed a suite of vectors to compare the activities of biotin ligase enzymes in yeast. We found that the newer TurboID versions were the most effective at labeling proteins, but they displayed low constitutive labeling of proteins even in the absence of exogenous biotin, due to biotin contained in the culture medium. We describe a simple strategy to express free BioID enzymes in cells that can be used as an appropriate control in BioID studies to account for the promiscuous labeling of proteins caused by random interactions between bait-BioID enzymes in cells. We also describe chemically-induced BioID systems exploiting the rapamycin-stabilized FRB-FKBP interaction. Finally, we used the TurboID version of the enzyme to explore the interactome of different subunits of the Ccr4-Not gene regulatory complex. We find that Ccr4-Not predominantly labeled cytoplasmic mRNA regulators, consistent with its function in mRNA decay and translation quality control in this cell compartment.

Insomnia and stress: the mediating roles of frontoparietal network.

Insomnia is a widespread health problem among adults, and it impairs cognitive control and emotional regulation functions. Stress and insomnia are positively correlated, and their vicious cycle has been widely reported. In this study, we explore the neural biomarkers of insomnia from the perspective of whole-brain functional connectivity and investigate the neural mechanisms underlying the association between stress and insomnia. The current study was conducted on a cross-sectional sample (N = 430). First, we investigated the correlation between perceived stress and insomnia. Second, we applied connectome-based predictive modeling (CPM) to determine the neuromarkers of insomnia. Finally, we explored the neural basis underlying the association between perceived stress and insomnia. A significant positive correlation was found between perceived stress and insomnia in the present research. Results of CPM revealed the following as the neural substrates supporting insomnia: the emotion regulation circuit involving repetitive negative thinking and the cognitive control circuit involving attention control. According to further results from mediation analysis, the frontoparietal network supporting cognitive emotion regulation is an important neural mechanism that maintains the correlation between stress and insomnia. The present study offers a profound insight into the alterations of brain activity related to insomnia, and it further investigates the neural underpinnings of the robust association between stress and insomnia. This study also opens new avenues for neural interventions to alleviate stress-related insomnia.

Inhibition of WNK Kinases in NK Cells Disrupts Cellular Osmoregulation and Control of Tumor Metastasis

Introduction: The serine/threonine with-no-lysine (WNK) kinase family function in blood pressure control, electrolyte homeostasis, and cellular osmoregulation. These kinases and their downstream effectors are considered promising therapeutic targets in hypertension and stroke. However, the role of WNK kinases in immune cells remains poorly understood. Methods: Using the small-molecule WNK kinase inhibitors WNK463 and WNK-IN-11, we investigated how WNK kinase inhibition affects natural killer (NK) cell physiology. Results: WNK kinase inhibition with WNK463 or WNK-IN-11 significantly decreased IL-2-activated NK cell volume, motility, and cytolytic activity. Treatment of NK cells with these inhibitors induced autophagy by activating AMPK and inhibiting mTOR signaling. Moreover, WNK kinase inhibition increased phosphorylation of Akt and c-Myc by misaligning activity of activating kinases and inhibitory phosphatases. Treatment of tumor-bearing mice with WNK463 impaired tumor metastasis control by adoptively transferred NK cells. Conclusion: The catalytic activity of WNK kinases has a critical role of multiple aspects of NK cell physiology and their pharmacologic inhibition negatively impacts NK cell function.

Cocreative Development of Robotic Interaction Systems for Health Care: Scoping Review.

Robotic technologies present challenges to health care professionals and are therefore rarely used. Barriers such as lack of controllability and adaptability and complex control functions affect the human-robot relationship. In addition to educational opportunities, the possibility of individual adaptation can improve the usability and practical implementation of robotics. Previous work has focused on developments from a technology-centered perspective and has included user interests too late in the process. This study addresses the following research question: What cocreative research approaches are used in the field of nursing robotics to improve the usability, intended use, and goal-directed application of robotic developments for nurses and to support the nursing process? This scoping review provides an overview of the topic and the research activities taking place within it. Five databases and the reference lists of the identified publications were searched for studies without further restrictions. Studies were included if they developed and evaluated interaction and control platforms for robotic systems in health care in a cocreative way with end users. The search resulted in 419 hits, of which 3 publications were included. All publications were feasibility or user studies that were mainly carried out in the European Union. The 3 interaction and control platforms presented were all prototypes and not commercially available. In addition to those in need of care, all studies also included family carers and health care professionals. Robotic interaction and control platforms in health care are rarely, if ever, developed and evaluated with feasibility or user studies that include prototypes and end users. While the involvement of end users is crucial, this review emphasizes that all stakeholders, including health care professionals, should participate in the development process to ensure a holistic understanding of application needs and a focus on user experiences and practical health care needs. It is emphasized that the active involvement of end users in the development process is critical to effectively meeting the needs of the target group.

Modeling environmental-born melioidosis dynamics with recurrence: An application of optimal control

Melioidosis is a significant health problem in tropical and subtropical regions, especially in Southeast Asia and Northern Australia. Recurrent melioidosis is a major obstacle to eliminating the disease from the community in these nations. This work aims to propose and analyze a human melioidosis model with recurrent phenomena and an optimal control model by incorporating time-dependent control functions. The basic reproduction number (R0) of the uncontrolled model is derived using the method of the next-generation matrix. Using the construction of a Lyapunov functional, we present the global asymptotic dynamics of the autonomous model in the presence of recurrent for both disease-free and endemic equilibria. The global asymptotic stability of the model’s equilibria shows the absence of a backward bifurcation for the model in both cases, whether in the absence or presence of relapse. The sensitivity analysis aims to identify the parameters that have the most significant impact on the model’s dynamics. Furthermore, qualitative analysis of the model’s global dynamics and the changing effect of the most influential parameters on R0 are supported by numerical experiments, with the results being illustrated graphically. The model with time-dependent controls is analyzed using optimal control theory to assess the impact of various intervention strategies on the spread of the epidemic. The numerical results of the optimality system are carried out using the Forward–Backward Sweep method in Matlab. We also conducted a cost-effectiveness analysis using two approaches: the average cost-effectiveness ratio and the incremental cost-effectiveness ratio.

Oncologic and functional outcomes following robot assisted radical prostatectomy: 15-Year experience in a Latin American referral center

BackgroundProstate cancer is the most common cancer in men with more than 52,000 cases diagnosed every year on average. With the introduction of robotic surgery, robotic assisted radical prostatectomy (RARP) has become a popular treatment option in recent years. Achieving oncological control, urinary continence and satisfactory erectile sexual function after RP is the main goal also known as “trifecta”. All these outcomes are highly influenced by surgical experience and caseload. The main objective of this study is to analyze oncological and functional outcomes in RARP after 15 years of experience. MethodsFrom 2008 until December 2023, 1790 RARP for localized prostate cancer were performed. A retrospective analysis was conducted based on prospectively collected data correlated with electronic medical records. ResultsSubgroup analyses were conducted in order to evaluate oncological and functional outcomes (n: 1400). Red blood cell transfusion and conversion to open surgery rate was 1.9 % and 0.1 %, respectively. Mean surgical time was 194 min. Mean follow-up time was 69.5 months, 23.8 % patients experienced biochemical recurrence and 1 % died, primarily due to disease progression. Estimated 10-year recurrence-free survival was 68.7 % (95 % CI 67.2–72.2) while estimated 10-year overall survival was 97.9 % (95 % CI 96.3–99.4). Overall urinary continence rate at 2 years was 86.9 % while satisfactory erectile function rate at 18 months was 56.8 %. ConclusionsRobotic-assisted radical prostatectomy has become a standard surgical technique in our urological practice for the management of clinically localized and locally advanced prostate tumors in selected cases. After 15 years since the inception of our robotic surgery program, we can conclude that our results are comparable to those published in the international literature, enabling patients to maintain satisfactory sexual function with a high continence rate within the first year of surgery.

Wardowski Contraction on Controlled S-Metric Type Spaces with Fixed Point Results

This article presents the concept of a triple controlled S-metric type space, characterized by three control functions: β, µ, and γ. This extends the idea of controlled S-metric type spaces. We explore several properties and provide illustrative examples. Furthermore, we introduce αs-admissible mappings and enhance Wardowski’s contraction principle by introducing (αs-F)-contractive mappings specifically designed for triple controlled S-metric type spaces. The article establishes the existence and uniqueness of fixed points within a complete triple controlled S-metric type space. Finally, we apply our main theorem to demonstrate the determination of a unique solution for an mth degree polynomial.

Metformin Improves Glycemic Control and Postprandial Metabolism and Enhances Postprandial Glucagon-Like Peptide 1 Secretion in Patients With Type 2 Diabetes and Heart Failure: A Randomized, Double-Blind, Placebo-Controlled Trial

This randomized trial tested the effect of metformin on glycemic control and cardiac function in patients with heart failure (HF) and type 2 diabetes while evaluating intestinal effects on selected gut microbiome products reflected by trimethylamine-N-oxide (TMAO) and gut-derived incretins. Metformin treatment improved glycemic control and postprandial metabolism and enhanced postprandial glucagon-like peptide 1 (GLP-1) secretion but did not influence cardiac function or the TMAO levels. Metabolic effects of metformin in HF may be mediated by an improvement in intestinal endocrine function and enhanced secretion of the gut-derived incretin GLP-1.

Isoperimetric Control of an Expanding Set

Consider a contaminated region in a 2-dimensional plane that is expanding with unit normal speed. Our goal is to apply a control function (e.g. pesticide) along the boundary of this region to reduce the contaminated area to zero in the shortest possible time, while consistently clearing a fixed amount of land per unit time. It has been proven that when the initial contamination forms a convex set, an optimal eradication strategy requires applying pesticide to the boundary segments with the highest curvature at each moment. This is equivalent to adopting a myopic strategy that minimizes the perimeter of the contaminated region at each time step. This result provided insight for developing numerical methods to compute approximations of these optimal strategies for convex sets. Namely, our simulation consists in alternating between computing the isoperimetric (perimeter-minimizing) profile with a convex constraint and then dilating the resulting set by a radius equal to the time mesh. This process is repeated until the shape reaches a circle, which can then be trivially scaled down to a point. The isoperimetric profile is obtained through morphological opening, an erosion-dilation operator commonly used in image processing for noise removal. A major open problem remains: a full characterization of optimal eradication strategies for initial contaminations of general shapes. We have applied the above numerical scheme with non-convex constraints to gain some intuition in this broader context. This may entail replacing the morphological opening operator with a more general algorithm relying on the medial axis of a shape. It turns out that, in some configurations, it is more effective to split the contamination into several components and shrink them separately.

Investigating the Immediate Effects of Static and Dynamic Stretching Exercises of Lower Extremities Muscles on Core Stability in Young Healthy Females

Introduction: This study investigates the immediate effects of warm-up exercises, specifically static and dynamic stretches for the lower extremities, on strength, endurance, flexibility, motor control, and core stability function in young, healthy females. Materials and Methods: A total of 60 healthy, active women aged 19-30 years were randomly divided into three groups as follows: Static stretching (SS), dynamic stretching (DS), and a control group (CG), which received no exercises. Evaluation methods for core stability included strength, endurance, sit-and-reach, Y-balance, and bilateral squat tests. Meanwhile, these tests were conducted before and after the prescribed exercise protocols. Results: Both the SS and DS groups experienced significant increases in all core stability components compared to their baseline values (P&lt;0.05). Meanwhile, the analysis of variance/ analysis of covariance indicated that immediately after performing the stretching exercises, the SS and DS groups exhibited significantly greater improvements in parameters, such as strength, endurance, flexibility, and balance tests (except for the posterior-medial direction) when compared to the CG (P&lt;0.05). Regarding functional parameters after the exercises, there were no statistically significant differences between the study groups (P&gt;0.05). In addition, dynamic exercises demonstrated a higher effectiveness than static exercises for most parameters (P&lt;0.05). Conclusion: Warm-up exercises, involving both static and dynamic stretches for lower limb muscles appear to have an immediate positive impact on core stability parameters. In sports that demand strong trunk muscles and balance, the dynamic protocol may be more effective

A new optimal 3° of freedom fractional order proportion integral derivative controller with model predictive controller for frequency regulation in high penetrated renewable based interconnected system

The increasing use of renewable energy sources (RESs) in conventional power systems is making them more complex. RES, such as solar and wind energy, reduce system inertia, affecting power system (PS) stability and frequency aberrations. Thus, the modern PS faces new concerns that arise from integrating RESs and struggles to manage frequency and stability, which can cause power outages and blackouts and lower industry production. The intelligent control mechanism is critical to the PS's operation to ensure frequency under its complicated structure. This study suggests a new best 3-DoF fractional order proportional integral derivative-model predictive controller (3DoF-FOPIDN-MPC) for controlling frequency when there is a lot of load going on quickly. The 3DoF-FOPID controls the outer loop using the area control error (ACE) signal, while MPC controls the inner loop using the output signal from the 3DoF-FOPIDN and the area's total power output response. For optimal controller functionality, the salp swarm algorithm (SSA) extracts optimized controller settings. To validate the suggested controller, it is tested under various load-changing scenarios and compared to state-of-the-art controllers. For 1 % and 3 % load changes, the suggested controller settles in 1.1 s and 1.78 s, respectively.

Study of the hydraulic characteristics of an airfoil‐shaped weir trough measurement and control integrated facility combined with numerical simulation

AbstractIn this study, an integrated measurement and control facility with an airfoil weir as the primary overcurrent structure is proposed by considering the flow characteristics over different shapes of weir trough facilities as well as the approach of merging measurement and control functions. The incomplete self‐similarity theory and dimensional analysis are used to derive the stage‐discharge relationship. The hydraulic characteristics of the facility under different shape‐related parameters, weir crest heights (rotation angles), and flows are studied by combining model testing and numerical simulation. The findings demonstrate that changes in shape‐ related parameters and rotation angle do not affect the linear relationship between the water depths in the critical and reference sections. The mean error in the discharge formula derived by dimensional analysis is 2%. The Froude number is less than 0.25 under all the working conditions. From the backwater height and head loss, it can be seen that the larger the P/C (the maximum airfoil thickness P to the chord length C ratio) value of the facility under the premise of unifying the weir crest height, the better the overflow capacity. When the height of the weir crest is 0.3778 m, the negative pressure on the surface of the airfoil weir increases with increasing P/C value.

Emerging roles of lipid and metabolic sensing in the neuroendocrine control of body weight and reproduction.

The hypothalamus lies at the intersection of brain and hormonal mechanisms governing essential bodily functions, including metabolic/body weight homeostasis and reproduction. While metabolism and fertility are precisely regulated by independent neuroendocrine axes, these are tightly connected, as reflection of the bidirectional interplay between the energy status of the organisms and their capacity to reproduce; a connection with important pathophysiological implications in disorders affecting these two crucial systems. Beyond the well-characterized roles of key hormones (e.g., leptin, insulin, ghrelin) and neuropeptides (e.g., melanocortins, kisspeptins) in the integral control of metabolism and reproduction, mounting evidence has pointed out a relevant function of cell energy sensors and lipid sensing mechanisms in the hypothalamic control of metabolism, with prominent roles also for metabolic sensors, such as mTOR, AMPK and SIRT1, in the nutritional regulation of key aspects of reproduction, such as pubertal maturation. We provide herein a synoptic overview of these novel regulatory pathways, with a particular focus on their putative function in the metabolic control of puberty, and delineate new avenues for further exploration of the intricate mechanisms whereby metabolism and reproduction are tightly connected.

Inverse problem of reconstructing source term for a class of non‐divergence parabolic equations

This paper explores an inverse problem pertaining to the determination of a source function in non‐divergence parabolic equations, where the solution is known at a discrete set of points. Being different from other ordinary inverse source problems, which are often dependent on only one variable, the unknown coefficient in this paper not only depends on the space variable but also depends on the time . On the basis of the optimal control framework, the existence of the optimal solution of the control function is proved. The necessary conditions to be satisfied by the optimal solution are given. The convergence of the optimal solution when the mesh parameters tend to zero is obtained. The conjugate gradient method is applied to the inverse problem and some numerical results are presented for various typical test examples.