Response Fluctuations Research Articles

Twinning and dynamic strain aging behavior during tensile deformation of Fe-Mn-C TWIP steel

The twinning and dynamic strain aging(DSA) induced work hardening in Fe-Mn-C TWIP steel has been experimentally investigated in view of grain morphology, stress strain response, local strain rate(LSR) and strain hardening rate. A strain of 0.3 should be the critical value for the saturation of twined grains in Fe-Mn-C TWIP steel with 0.4–0.6wt% carbon and 18–22wt% manganese. DSA can occur in the very beginning of plastic deformation in Fe-Mn-C TWIP steel with the unpronounced fluctuation in stress strain response but obvious discontinuity in work hardening and LSR. The mechanism on strain hardening of Fe-Mn-C TWIP steel during tensile deformation can be distinguished by the variation of LSR. Twinning induced hardening rate is around 3.0GPa with a steady LSR, while DSA induced hardening rate is about 2.0GPa with a periodic and unstable fluctuation of LSR. There are mainly three stages in the work hardening of Fe-Mn-C TWIP steel divided by the inducing mechanism: twinning dominant, twinning+DSA dominant and DSA dominant. A strong correlation between the fluctuating characteristic of LSR and work hardening rate has been observed. In twinning dominant stage, they are largely steady; while in the other two stages, more significant fluctuation is observed where DSA is more pronounced for both curves. The serration in stress corresponds to the plateau in strain and low LSR, as well as the peak of strain hardening rate, due to the occurrence of DSA; and the smooth stress evolution between two serrations correlates the apparent increase of strain, and high LSR, together with the trough of strain hardening rate, relating to the preparation time for next DSA.

Precuneus degeneration and isolated apathy in patients with Parkinson's disease.

To investigate isolated apathy in a set of consecutively enrolled Parkinson's disease (PD) patients without dementia, depression, and significant motor response fluctuations, by conducting neuropsychological and neuroimaging analyses. One hundred twenty-four patients were eligible for inclusion in this study. Clinical information and data were collected from a predefined neuropsychological test battery, including the mini-mental status examination, apathy scale, geriatric depression scale, digit span test, Boston naming test, Seoul verbal learning test, controlled oral word association test, go-no-go test, and the Rey figure copy test. From matched groups of 10 non-apathetic and 12 apathetic patients in the initial cohort and 9 healthy controls, [18F]fluorodeoxyglucose positron emission tomography and volumetric magnetic resonance images were acquired. Apathy was detected in 59.7% of the initial cohort. Apathetic patients had lower scores in the digit span forward, digit span backward, and immediate recall of verbal learning tests than did those without apathy (p <0.05). The results were unaffected by parkinsonian motor severity and medication dose. Neuroimaging analyses revealed precuneus atrophy and hypometabolism in patients with isolated apathy. These precuneus changes were well-correlated with apathy severity (p <0.001). Apathy severity was also positively correlated with gray matter volume in the superior frontal gyrus and cerebellar vermis, and with metabolism in the medial frontal and anterior cingulate regions (p < 0.001). PD patients with isolated apathy showed attention and working memory dysfunction, and precuneus degeneration might be related to this distinctive nonmotor symptom in PD.

MAXIMUM INFLUENCE OF NONIDENTICAL R- AND C-ELEMENTS OF A HIGH-VOLTAGE DIVIDER ON ITS FREQUENCY CHARACTERISTICS

This paper describes the impact of non-identical resistive and capacitive elements of high-voltage arm of mixed voltage divider on its frequency characteristics. The authors emphasized the general features and substantiated main shortcomings of existing methods of calculating the characteristics of high-voltage dividers. The analytical expressions received for influence study of non-identical elements of a high-voltage divider at extreme discrete distribution of these elements. Feature of the received analytical expressions is that they are valid for any values of not identity as for resistive, and capacitive elements, and also their cumulative action. It is shown that the selected discrete distribution of resistive and capacitive elements influence of their not identity on fluctuations of amplitude frequency response and the phase-frequency characteristic of a voltage divider increases more than five times in relation to triangular distribution of parameters of elements in case of equal values of their maximum deviations (from mean values). The maximum influence of not identity of resistive and capacitive elements of a high-voltage arm on its frequency characteristics was studied. The influence becomes significant at its extreme discrete distribution and can be considered as the worst case of influence of not identity of the components of a high-voltage arm of a voltage divider. The results received in the article are recommended for assessment from above of influence of not identity of resistive and capacitive elements of a high-voltage divider on his frequency characteristics that allows to define possible values of not identity of elements of a high-voltage arm depending on permissible instability of frequency characteristics of the voltage divider.

Dynamic response analysis of an overhung rotor with interval uncertainties

Rotor system is an important part in rotating machineries. As a matter of fact, rotors are subject to uncertainties inevitably due to occasions such as assembling errors, material properties dispersion and variable working conditions. In order to obtain more reasonable evaluations of dynamic response of rotor systems, uncertainties are recommended to be taken into consideration. In this paper, the dynamic responses of an elastically supported uncertain overhung rotor are studied in which uncertain parameters are treated as unknown-but-bounded interval variables. The finite element method is used to derive the deterministic analysis model. A non-intrusive interval method based on Chebyshev polynomial approximation is proposed to evaluate the uncertain dynamic response of the rotor system. Comparative study of the interval method, the scanning method and the Monte Carlo simulation is carried out to illustrate the effectiveness and accuracy. Deflection upper bounds and lower bounds of the disc are obtained with respect to rotating speed in several typical uncertain cases. Results show that the uncertainties have significant effects on the dynamic behaviours of the rotor system and multiple source small uncertainties can lead to large fluctuations in the dynamic responses.

Photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films in an aerated 0.5 M NaCl solution

This research aimed to investigate the photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films using electrochemical measurements in an aerated 0.5M NaCl solution under white light illumination. The CdS/TiO2 nanocomposite films were prepared by chemical bath deposition technique in a solution of cadmium and sulfide ions. The high resolution images of CdS/TiO2 nanocomposite films were provided by field emission scanning electron microscope. Theirs chemical identification and quantitative compositional information, crystallinity and actual chemical compounds formed were determined by energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The results indicated that the photoelectrochemical activity of the films depended strongly on CdS content. From the preparation of CdS/TiO2 nanocomposite films by 5, 10 and 15 dipping cycles in the chemical solutions, the best photoelectrochemical response was revealed by the 10 dipping cycles-prepared film. Galvanic couple testing demonstrated that the photoelectrochemical response of the film decreased continuously compared to that of anodized nanoporous TiO2 substrate which described by photocorrosion of CdS nanoparticles. In addition, chloride-ion attack also induced pitting corrosion leading to fluctuation and deterioration of photoelectrochemical response. CdO2 and Cd(OH)2 depositions were found as the main photocorrosion products on collapsed nanostructured-surface. The relevance between photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite film was discussed in detail.

Adipose type one innate lymphoid cells regulate macrophage homeostasis through targeted cytotoxicity

Abstract Adipose tissue has a dynamic immune system that adapts to changes in diet and maintains homeostatic tissue remodeling. Recently, adipose type 1 innate lymphoid cells (AT1-ILCs) were reported to promote proinflammatory M1 macrophages in obesity. However, their role at steady state remains unknown. Here we reveal heterogeneous populations of AT1-ILCs in humans and mice. Using parabiotic mice fed HFD, we found that AT1- ILCs had differential trafficking and proliferation features. AT1-ILCs displayed fluctuations in response to short and long term HFD and could revert to regular levels upon diet restriction. Unexpectedly, all AT1-ILCs were able to kill macrophages at steady state, especially tissue repair-associated M2 macrophages. T1-ILCs-depleted and perforin-deficient mice had increased M2:M1 ratios. Diet-induced obesity impaired AT1-ILCs killing ability. Adoptive transfer of AT-1ILCs from lean to obese mice reduced total macrophages but increased M1:M2 ratio. Collectively, we show that AT1-ILCs are essential for regulating macrophage homeostasis through targeted cytotoxicity.

Continuous Assessment of Levodopa Response in Parkinson's Disease Using Wearable Motion Sensors

Fluctuations in response to levodopa in Parkinson's disease (PD) are difficult to treat as tools to monitor temporal patterns of symptoms are hampered by several challenges. The objective was to use wearable sensors to quantify the dose response of tremor, bradykinesia, and dyskinesia in individuals with PD. Thirteen individuals with PD and fluctuating motor benefit were instrumented with wrist and ankle motion sensors and recorded by video. Kinematic data were recorded as subjects completed a series of activities in a simulated home environment through transition from off to on medication. Subjects were evaluated using the unified Parkinson disease rating scale motor exam (UPDRS-III) at the start and end of data collection. Algorithms were applied to the kinematic data to score tremor, bradykinesia, and dyskinesia. A blinded clinician rated severity observed on video. Accuracy of algorithms was evaluated by comparing scores with clinician ratings using a receiver operating characteristic (ROC) analysis. Algorithm scores for tremor, bradykinesia, and dyskinesia agreed with clinician ratings of video recordings (ROC area > 0.8). Summary metrics extracted from time intervals before and after taking medication provided quantitative measures of therapeutic response (p < 0.01). Radar charts provided intuitive visualization, with graphical features correlated with UPDRS-III scores (R = 0.81). A system with wrist and ankle motion sensors can provide accurate measures of tremor, bradykinesia, and dyskinesia as patients complete routine activities. This technology could provide insight on motor fluctuations in the context of daily life to guide clinical management and aid in development of new therapies.

Performance evaluation of machinery for sugarcane handling and trash management

The sugarcane cultivation and sugar industry in India plays a vital role towards socio-economic development in the rural areas by mobilizing rural resources and generating higher income and employment opportunities. About 7.5 per cent of the rural population, covering about 45 million sugarcane farmers, their dependents and a large number of agricultural labour are involved in sugarcane cultivation, harvesting and ancillary activities. There are about nine States in India where sugarcane is grown on a large extent of area. There are a number of varieties that are grown in India depending on the suitability of the soil. The area, output and yield and sugarcane cultivation is subjected to fluctuate in response to policies of the government and also conditions of cultivation. Sugarcane is a labour intensive crop and shortage of labour and unavailability of labour at reasonable rate is the major concern in sugarcane cultivation. To combat the paucity of labour, mechanized sugarcane cultivation is the only option to carry out all the operations in time. The next phase of revolution in Indian agriculture is bound to come through the use of improved agricultural machinery suiting to local conditions. The performance evaluation of sugarcane handling equipments like tractor front mounted sugarcane loader, tractor operated sugarcane billets collector cum unloader and tractor PTO operated sugarcane trash shredder were conducted at Farm Machinery Testing Centre, CCSHAU, Hisar and the performance has been found to be satisfactory. Concerted efforts are required to formulate a strategy for mechanising sugarcane production in India with the sole aim of increasing production and productivity per unit time, area and input at reduced cost of unit operation to survive in the highly competitive international sugar market.

Dynamical Timescale Explains Marginal Stability in Excitability Dynamics.

Action potentials, taking place over milliseconds, are the basis of neural computation. However, the dynamics of excitability over longer, behaviorally relevant timescales remain underexplored. A recent experiment used long-term recordings from single neurons to reveal multiple timescale fluctuations in response to constant stimuli, along with more reliable responses to variable stimuli. Here, we demonstrate that this apparent paradox is resolved if neurons operate in a marginally stable dynamic regime, which we reveal using a novel inference method. Excitability in this regime is characterized by large fluctuations while retaining high sensitivity to external varying stimuli. A new model with a dynamic recovery timescale that interacts with excitability captures this dynamic regime and predicts the neurons' response with high accuracy. The model explains most experimental observations under several stimulus statistics. The compact structure of our model permits further exploration on the network level.SIGNIFICANCE STATEMENT Excitability is the basis for all neural computations and its long-term dynamics reveal a complex combination of many timescales. We discovered that neural excitability operates under a marginally stable regime in which the system is dominated by internal fluctuation while retaining high sensitivity to externally varying stimuli. We offer a novel approach to modeling excitability dynamics by assuming that the recovery timescale is itself a dynamic variable. Our model is able to capture a wide range of experimental phenomena using few parameters with significantly higher predictive power than previous models.

On the localized quantum oscillators in a common heat bath

To remedy the failure of minimal coupling method in describing the quantum dynamics of two localized Brownian oscillators interacting with a common medium, a scheme is introduced to model the medium by a continuum of complex scalar fields or equivalently two independent real scalar fields. The starting point is a Lagrangian of the total system and quantization is achieved in the framework of canonical quantization. The equations of motion, memory or response functions and fluctuation–dissipation relations are obtained. An induced force between oscillators is obtained originating from the fluctuations of the medium. Ohmic and non-Ohmic regimes are discussed and the positions of oscillators are obtained approximately in large time limit and weak coupling regime. Quantum entanglement between localized oscillators is obtained in zero temperature and strong coupling regime.

Dynamic simulation studies for boiler draft

Increasingly strict NOx and SOx emission limits demand the fossil and fuel fired power industry to upgrade their gas treatment system with Flue Gas Desulphurization (FGD) and Selective Catalytic Reduction (SCR) equipment. To compensate for the additional pressure drop the new equipment introduces into the flue gas path due, the existing induced draft (ID) fans need to be replaced with higher head fans or new booster fans. This requires new duct work to connect the equipment. While the new duct work can be designed considering the new operating conditions, the existing duct work may not have been designed with these unanticipated changes and hence may be at risk of implosion and mechanical damage. This paper examines how a high-fidelity process and control model of the air, furnace, and flue gas path of a coal fired power plant is developed for a transient analysis study by using a dynamic simulation platform – DYNSIM. Also included is a case-study which evaluated the processes dynamics of a 225MW unit. The objective of the study was to ensure design safety by evaluating the process dynamics of the unit prior to retrofitting the unit’s draft system. The model, validated with historian data and design data, was used to evaluate the air and flue gas system pressure fluctuations in response to upsets such as fan trips and runaways. The resulting pressures were then available for use as a basis for the duct work design.

Dynamic Flexibility Index Sheds Light on Pin1 Allostery

Allostery, which is regulation from distant sites, plays a major role in biology. Pin1 is a modular protein containing a WW domain and a larger peptidyl prolyl isomarase domain (PPIase) that isomerizes phospho-serine/threonine-proline (pS/T-P) motifs, which are critical for signaling within intrinsically disordered loops of cell cycle proteins. Pin1 utilizes allosteric regulations for its function, and binds (pS/T-P) motifs in both domains. The WW domain serves as a docking module, whereas catalysis solely takes place within the PPIase domain. However, enzymatic activity gets enhanced when WW is in the bound form, highlighting PIN1's allosteric regulation. Previous work using NMR and molecular dynamics analysis has shown that binding induced quenching of fast local motions and strengthening of the interaction between two domains, indicated in particular by decrease in flexibility of catalytic loops. Here we present a novel method, the dynamic flexibility index (DFI) analysis, for characterizing the underlying allosteric communications between two domains. DFI measures the resilience of a given position to the perturbations that occur at different parts of the protein, using linear response theory. This index captures multi-dimensional effects when the protein is displaced out of equilibrium. Moreover, we can also identify the allosteric response in dynamic flexibility based on the perturbation response fluctuation profile of the PPIase domain upon WW binding and distinguish the positions that contribute the most. Finally we also explore the mechanistic link between conformational dynamics and co-evolution to identify mutational positions to alter enzymatic function.

Delayed Gastric Emptying in Advanced Parkinson Disease: Correlation With Therapeutic Doses.

Gastrointestinal dysfunction is often described in patients with Parkinson disease (PD), and gastrointestinal symptoms are usually attributed to gastroparesis. The consequent delayed gastric emptying (GE) may be an important pharmacokinetic mechanism underlying some of the response fluctuations that develop after long-term levodopa (L-dopa) therapy.The aim of this prospective study was to assess GE time by a liquid meal scintigraphy, in PD patients, and to correlate them with demographic, clinical, and therapeutic data. Scintigraphy with radiolabeled albumin nanocolloids added to acidified orange juice was performed in 51 consecutive PD patients 1 hour after their usual dopaminergic therapy first dose and after a 12-hour fast. Demographic, neurologic, gastrointestinal, and pharmacologic data were collected. Fifty-one patients were divided into 2 groups using the cutoff point obtained in normal subjects (40 minutes): group 1 included 29 patients with GE T½ of 27.60 ± 7.30 minutes (normal), group 2 showed a GE T½ of 84.90 ± 53.80 minutes (delayed). The most striking significant difference between the 2 groups was the dopa-decarboxylase inhibitor mean dose that was significantly higher in the group of patients with delayed GE (201.32 ± 97.26 vs 127.65 ± 79.74; P = 0.005). The impairment of gastric motility, frequently represented in PD patients, occurs in approximately 42% of patients with motor complications. A mechanism that may explain the GE delay is the effect of L-dopa on dopaminergic receptors in the stomach. Therefore, the dosage of dopa-decarboxylase inhibitor, increasing the L-dopa concentration, may contribute to GE delay and its consequent effect on drug delivery and efficacy.

Nonmotor Symptoms and Natural History of Parkinson's Disease: Evidence From Cognitive Dysfunction and Role of Noninvasive Interventions.

Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by motor and nonmotor symptoms (NMS). Several subsequent studies substantiate the great functional burden related to NMS, their progression, and negative effect on quality of life in PD. Additional evidence indicates interesting relationships between striatal dopaminergic function and NMS. The basal ganglia are implicated in the modulation and integration of sensory information and pain, bladder function is under control of both inhibitory (D1) and facilitatory (D2) dopaminergic inputs, finally reduced dopaminergic activity in the mesocortical and mesolimbic pathways is involved in the development of several NMS including mood, motivational, and cognitive alterations. Some NMS fluctuate in response to dopaminergic treatment and are relieved by dopamine replacement therapy, other are insensitive to current therapeutic strategies. The relation among the overall disease complications, perhaps the most important for PD patients and family members' well-being and functionality is dementia that affects most PD patients over the course of disease. Specific pharmacological treatment is lacking, and alternative approaches have been implemented to improve everyday functionality and quality of life. The state of the art suggests that cognitive rehabilitation in PD is possible and may either increase performance or preserve cognitive level over the time. However, it is also evident that cognitive abnormalities in PD are heterogeneous and we still do not have biomarkers to detect early patients at risk for dementia. Cognitive dysfunction is one the most prevalent NMS and is a clinically and functionally important disease milestone. Given the available clinical and imaging evidence it is possible to use cognition to model NMS progression and design nonpharmacological interventions. In this chapter we will address the use of cognitive rehabilitation and noninvasive brain stimulation techniques to modulate cognitive performance and rescue connectivity in affected brain circuitry.

Human Cardiopoietic Amniotic Fluid cell population: characterization and terminal differentiation

Rationale. Human amniotic fluid-derived (hAF) stem cells are considered a novel class of multipotent stem cells, sharing characteristics of both embryonic and adult stem cells. In fact, they proliferate rapidly, are able to differentiate into cells of all the embryonic germ layers, but do not form teratoma. It has been already reported that the embryoid bodies (EBs) obtained from hAFs have a cardiac potential, but it has not been described a functional terminal differentiation in cardiomyocytes (CMs) yet. Objective. Aim of this study was to foster the cardiomyogenic potential of hAFs in order to obtain a cellular population with morphological and functional features of CMs. Methods and Results. AFCs were exposed sequentially to inducing factors (Ascorbic Acid, 5-Azacytidine, BMP4, ActivinA, VEGF) up to 15 days and differentiation was monitored. Only the hAF samples expressing the multipotency markers SSEA4, OCT4 and CD90 (CardiopoieticAF) responded to the differentiation process loosing their stemness and increasing the cardiac nuclear factors NKX2.5 and GATA4. After the differentiation cells expressed high levels of the sarcomeric proteins (cTnT, αMHC and αSA), the gap junction marker Connexin43 and both atrial and ventricular markers; moreover, up to 90% of the cells was positive for CACNA1C and SERCA2a, cardiac calcium pumps involved in the excitation/contraction coupling, and about 30% of the CardiopoieticAF-derived cells presented spontaneous intracellular Ca2+ waves and Ca2+ fluctuation in response to caffeine or adrenergic stimulation. Some spontaneous beating foci were also observed. Conclusion. Our results demonstrate that CardiopoietichAFs can fully differentiate into a homogenous population of CM-like cells, characterized by cardiac-specific molecular, structural, and functional properties. Thus, CardiopoietichAFs can hold great promise for the development of in vitro models of cardiac genetic disorders, for drug discovery and testing, and for the emerging field of cardiovascular regenerative medicine.

Plasma sFlt-1 Fluctuations in Response to Pulmonary Arterial Hypertension Treatment

Background: Pulmonary Arterial Hypertension (PAH) is characterized by vasoconstriction and remodeling of distal pulmonary arteries, which result in increased Pulmonary Vascular Resistance (PVR) and right ventricular overload. In the present study, we measured plasma fluctuations of nine proteins, involved in inflammation or tyrosine kinase signaling, in PAH patients, to assess their value as biomarkers of treatment response. Methods: Plasma vascular endothelial growth factor A and D, soluble fms-like tyrosine kinase-1 (sFlt-1), placenta growth factor, fibroblast growth factor 2, angiopoietin-1 receptor, interleukin (IL)-6 and -8 and tumor necrosis factor α were determined by multiplex immunoassays in 21 treatment-naive PAH patients at baseline and at first and second clinical checkups. Results: From baseline to first checkup, sFlt-1 (p<0.02) and IL-6 (p<0.005) decreased in PAH patients. sFlt-1 remained decreased (p<0.003) at the second checkup, compared to baseline. No significant changes were observed in the other measured biomarkers. Patients receiving initial combination therapy showed a more marked initial decrease (p<0.02) in plasma sFlt-1, compared to initial monotherapy. Plasma sFlt-1 changes correlated positively with changes in PVR and negatively with changes in left ventricular stroke work index (LVSWI). Conclusion: Plasma sFlt-1 is significantly reduced after the initiation of PAH-specific treatment and its fluctuations are correlated to changes in PVR and LVSWI. Thus, plasma sFlt-1 is a new potential biomarker for evaluating treatment response in PAH

Risk factors for levodopa-induced dyskinesia in Parkinson’s disease patients

Background/Aim. Levodopa, the precursor of dopamine, is a substitute therapy for Parkinson''s disease. Long-term application of levodopa causes fluctuation in motor response and the occurrence of involuntary movements or dyskinesia. The aim of this study was to assess the risk factors for dyskinesia in Parkinson?s disease (PD) patients undergoing treatment with levodopa. Methods. We included 177 consecutive outpatients with PD, who had been undergoing treatment for at least six months. A semi-structured interview was used to collect demo-graphic and clinical data as well as a number of clinical scales. Results. Patients with dyskinesia (n = 90) were younger at dis-ease onset and had longer disease duration. They had higher Unified Parkinson''s Disease Rating Scale (UPDRS) scores and more frequently had other motor complications, such as wearing-off and freezing of gait, as well as non-motor ones, such as psychosis. They took higher levodopa doses and levodopa equivalent doses and were on levodopa therapy for a longer period of time. Multivariate analysis yielded that in-dependent risk factors for dyskinesia were: disease duration of longer than 10 years

The angular dependence of pulse shape discrimination and detection sensitivity in cylindrical and cubic EJ-309 organic liquid scintillators

Liquid scintillators are used widely for neutron detection and for the assay of nuclear materials. However, due to the constituents of the detector and the nitrogen void within the detector cell, usually incorporated to accommodate any expansion that might occur to avoid leakage, fluctuations in detector response have been observed associated with the orientation of the detector when in use. In this work the angular dependence of the pulse-shape discrimination performance in an EJ309 liquid scintillator has been investigated with 252Cf in terms of the separation of γ -ray and neutron events, described quantitatively by the figure-of-merit. A subtle dependence in terms of pulse-shape discrimination is observed. In contrast, a more significant dependence of detection sensitivity with the angle of orientation is evident.

Twisting control algorithm for the yaw and pitch tracking of a twin rotor UAV

In this paper, second order sliding mode controller is used to compensate the pitch and yaw angles of multivariable (MIMO) twin rotor system. Twin rotor has six state variables including yaw and pitch angles, yaw and pitch angular velocities, and armature currents. Considering the physical structure of twin rotor, the controller aims to track the mentioned angles and stabilise their angular velocities. Two sliding surfaces are defined as the sum of tracking error of yaw and pitch angles and their integrals. The controller performance is studied in the light of tracking accuracy and steady-state error, transient behaviour and response fluctuations level, consistency. The closed-loop system performance will also be studied in the light of disturbance effect rejection, presence of uncertainty in the model, and presence of estimated practical noise. The simulation is presented for first and second order sliding mode controllers and their advantages and disadvantages will be investigated.

Cortical interactions during the resolution of information processing demands in autism spectrum disorders

IntroductionOur flexible and adaptive interactions with the environment are guided by our individual representation of the physical world, estimated through sensation and evaluation of available information against prior knowledge. When linking sensory evidence with higher‐level expectations for action, the central nervous system (CNS) in typically developing (TD) individuals relies in part on distributed and interacting cortical regions to communicate neuronal signals flexibly across the brain. Increasing evidence suggests that the balance between levels of signal and noise during information processing may be disrupted in individuals with Autism Spectrum Disorders (ASD).MethodsParticipants with and without ASD performed a visuospatial interference task while undergoing functional Magnetic Resonance Imaging (fMRI). We empirically estimated parameters characterizing participants’ latencies and their subtle fluctuations (noise accumulation) over the 16‐min scan. We modeled hemodynamic activation and used seed‐based analyses of neural coupling to study dysfunction in interference‐specific connectivity in a subset of ASD participants who were nonparametrically matched to TD participants on age, male‐to‐female ratio, and magnitude of movement during the scan.ResultsStochastic patterns of response fluctuations reveal significantly higher noise‐to‐signal levels and a more random and noisy structure in ASD versus TD participants, and in particular ASD adults who have the greatest clinical autistic deficits. While individuals with ASD show an overall weaker modulation of interference‐specific functional connectivity relative to TD individuals, in particular between the seeds of Anterior Cingulate Cortex (ACC) and Inferior Parietal Sulcus (IPS) and the rest of the brain, we found that in ASD, higher uncertainty during the task is linked to increased interference‐specific coupling between bilateral anterior insula and prefrontal cortex.ConclusionsSubtle and informative differences in the structure of experiencing information exist between ASD and TD individuals. Our findings reveal in ASD an atypical capacity to apply previously perceived information in a manner optimal for adaptive functioning, plausibly revealing suboptimal message‐passing across the CNS.