Design and Analysis of the Voltage Controller for the Non Isolated Boost DC-DC Convertor

In this paper, a controller has been presented by the root locus method based on the state space average model of the boost switching regulator with all of the converter’s parameters and uncertainties. In this model, the load current is unknown and the inductor, capacitor, diode and active switch are non ideal and have an on-state resistance. Furthermore, an on-state voltage drop has been considered for diode and active switch. By neglecting the load current and assuming the ideal elements the simplified model of the regulator has been caddied out. By these complete and simplified models, a step by step method has been proposed to design a single input single output (SISO), second order controller based on roots locus method. In this regard the controller's electronic circuit has been introduced by operational amplifiers. At the end, by simulation of the complete closed-loop system in MATLAB Simulink environment and comparing its results by the results of the regulator and controller circuits in PLECS, the accuracy of the designed controller performance has been shown

A New MATLAB GUI Tool for Instructing Operation of Power Electronic Rectifiers

This study seeks to present an interactive tool, which exploits the GUI related abilities in MATLAB, to investigate power electronic rectifiers operation. The present paper aims to show a flexible and extendable environment for steady state simulation of ideal controlled, uncontrolled, single-phase and three-phase power electronic rectifiers. This is accomplished at the presence of R, L and E loads with or without a flywheel diode. The easy application of our tool makes it feasible to be used by the teacher in the classroom. Also its short running time and the PSpice output netlist make it a remarkable alternative to the MATLAB PowerSim toolbox and PSIM software for studying ac-dc converters. Furthermore, in this paper some basic equations were introduced to analyze single and three-phase rectifiers. Because these equations are common between ac-dc converters, analyzing the different types of rectifiers will be easy for the students. The penultimate issue refers that, the proposed program can cause a variety of single and three phase controlled rectifiers accompanied by various combinations of R, L and E loads to be simulated. Ultimately, obtained results are compared to another well-known simulator’s such as PSpice to verify their accuracy

Linked patterns of biological and environmental covariation with brain structure in adolescence : a population-based longitudinal study

Adolescence is a period of major brain reorganization shaped by biologically timed and by environmental factors. We sought to discover linked patterns of covariation between brain structural development and a wide array of these factors by leveraging data from the IMAGEN study, a longitudinal population-based cohort of adolescents. Brain structural measures and a comprehensive array of non-imaging features (relating to demographic, anthropometric, and psychosocial characteristics) were available on 1476 IMAGEN participants aged 14 years and from a subsample reassessed at age 19 years (n = 714). We applied sparse canonical correlation analyses (sCCA) to the cross-sectional and longitudinal data to extract modes with maximum covariation between neuroimaging and non-imaging measures. Separate sCCAs for cortical thickness, cortical surface area and subcortical volumes confirmed that each imaging phenotype was correlated with non-imaging features (sCCA r range: 0.30-0.65, all P-FDR <0.001). Total intracranial volume and global measures of cortical thickness and surface area had the highest canonical cross-loadings (|rho| = 0.31-0.61). Age, physical growth and sex had the highest association with adolescent brain structure (|rho| = 0.24-0.62); at baseline, further significant positive associations were noted for cognitive measures while negative associations were observed at both time points for prenatal parental smoking, life events, and negative affect and substance use in youth (|rho| = 0.10-0.23). Sex, physical growth and age are the dominant influences on adolescent brain development. We highlight the persistent negative influences of prenatal parental smoking and youth substance use as they are modifiable and of relevance for public health initiatives.Peer reviewe

Neural Signatures of Data-Driven Psychopathology Dimensions at the Transition to Adolescence

Background One of the challenges in human neuroscience is to uncover associations between brain organization and psychopathology in order to better understand the biological underpinnings of mental disorders. Here, we aimed to characterize the neural correlates of psychopathology dimensions obtained using two conceptually different data-driven approaches. Methods Dimensions of psychopathology that were either maximally dissociable or correlated were respectively extracted by independent component analysis (ICA) and exploratory factor analysis (EFA) applied to the Childhood Behavior Checklist items from 9-to 10-year-olds (n = 9983; 47.8% female, 50.8% white) participating in the Adolescent Brain Cognitive Development study. The patterns of brain morphometry, white matter integrity and resting-state connectivity associated with each dimension were identified using kernel-based regularized least squares and compared between dimensions using Spearman's correlation coefficient. Results ICA identified three psychopathology dimensions, representing opposition-disinhibition, cognitive dyscontrol, and negative affect, with distinct brain correlates. Opposition-disinhibition was negatively associated with cortical surface area, cognitive dyscontrol was negatively associated with anatomical and functional dysconnectivity while negative affect did not show discernable associations with any neuroimaging measure. EFA identified three dimensions representing broad externalizing, neurodevelopmental, and broad Internalizing problems with partially overlapping brain correlates. All EFA-derived dimensions were negatively associated with cortical surface area, whereas measures of functional and structural connectivity were associated only with the neurodevelopmental dimension. Conclusions This study highlights the importance of cortical surface area and global connectivity for psychopathology in preadolescents and provides evidence for dissociable psychopathology dimensions with distinct brain correlates.</p

The Effectiveness of Pharmacological and Non-Pharmacological Interventions for Improving Glycaemic Control in Adults with Severe Mental Illness: A Systematic Review and Meta-Analysis

People with severe mental illness (SMI) have reduced life expectancy compared with the general population, which can be explained partly by their increased risk of diabetes. We conducted a meta-analysis to determine the clinical effectiveness of pharmacological and non-pharmacological interventions for improving glycaemic control in people with SMI (PROSPERO registration: CRD42015015558). A systematic literature search was performed on 30/10/2015 to identify randomised controlled trials (RCTs) in adults with SMI, with or without a diagnosis of diabetes that measured fasting blood glucose or glycated haemoglobin (HbA1c). Screening and data extraction were carried out independently by two reviewers. We used random effects meta-analysis to estimate effectiveness, and subgroup analysis and univariate meta-regression to explore heterogeneity. The Cochrane Collaboration’s tool was used to assess risk of bias. We found 54 eligible RCTs in 4,392 adults (40 pharmacological, 13 behavioural, one mixed intervention). Data for meta-analysis were available from 48 RCTs (n = 4052). Both pharmacological (mean difference (MD), -0.11mmol/L; 95% confidence interval (CI), [-0.19, -0.02], p = 0.02, n = 2536) and behavioural interventions (MD, -0.28mmol//L; 95% CI, [-0.43, -0.12], p<0.001, n = 956) were effective in lowering fasting glucose, but not HbA1c (pharmacological MD, -0.03%; 95% CI, [-0.12, 0.06], p = 0.52, n = 1515; behavioural MD, 0.18%; 95% CI, [-0.07, 0.42], p = 0.16, n = 140) compared with usual care or placebo. In subgroup analysis of pharmacological interventions, metformin and antipsychotic switching strategies improved HbA1c. Behavioural interventions of longer duration and those including repeated physical activity had greater effects on fasting glucose than those without these characteristics. Baseline levels of fasting glucose explained some of the heterogeneity in behavioural interventions but not in pharmacological interventions. Although the strength of the evidence is limited by inadequate trial design and reporting and significant heterogeneity, there is some evidence that behavioural interventions, antipsychotic switching, and metformin can lead to clinically important improvements in glycaemic measurements in adults with SMI

Cortical Thickness and Subcortical Volume Trajectories Across the Lifespan: Data From 14,600 Healthy Individuals Aged 6-90 Years

Background: Age is a critical determinant of brain morphometry. We formed the Lifespan Working group of the Enhancing Neuroimaging Genetics through Meta-Analysis(ENIGMA) Consortium to perform a large-scale analysis of cortical thickness data across more than 79 samples and14,600 healthy individuals aged 6-90 years. Methods: We used fractional polynomial (FP) regression to characterize age-related trajectories in brain morphometry. Normalized growth centiles were constructed using the para-metric Lambda, Mu, and Sigma (LMS) method. Inter-individual variability was analyzed using meta-analysis and one-way analysis of variance. Results: The volume of subcortical regions followed an inverted U-shaped trajectory while cortical thickness in almost all regions decreased during the first two to three decades of life and showed an attenuated or plateaued slope afterwards. Exceptions were the entorhinal, anterior cingulate and temporopolar cortices that followed attenuated age-related U-shaped trajectories. Age and its FP combinations explained up to 48% variance in morphometry. Sample, strength of the MRI scanner magnetic field and FreeSurfer version jointly accounted for a median of 17% of the variance. Conclusions: Our results could shed light on the uncertainties about age-related developmental trajectories of cortical thickness. The estimated centile values will provide scientists and clinicians with more efficient tools to detect brain morphological deviations and their association with behavioral, cognitive and clinical outcome

Personalized Estimates of Brain Structural Variability in Individuals With Early Psychosis

Early psychosis in first-episode psychosis (FEP) and clinical high-risk (CHR) individuals has been associated with alterations in mean regional measures of brain morphology. Examination of variability in brain morphology could assist in quantifying the degree of brain structural heterogeneity in clinical relative to healthy control (HC) samples.; Structural magnetic resonance imaging data were obtained from CHR (n = 71), FEP (n = 72), and HC individuals (n = 55). Regional brain variability in cortical thickness (CT), surface area (SA), and subcortical volume (SV) was assessed with the coefficient of variation (CV). Furthermore, the person-based similarity index (PBSI) was employed to quantify the similarity of CT, SA, and SV profile of each individual to others within the same diagnostic group. Normative modeling of the PBSI-CT, PBSI-SA, and PBSI-SV was used to identify CHR and FEP individuals whose scores deviated markedly from those of the healthy individuals.; There was no effect of diagnosis on the CV for any regional measure (P > .38). CHR and FEP individuals differed significantly from the HC group in terms of PBSI-CT (P < .0001), PBSI-SA (P < .0001), and PBSI-SV (P = .01). In the clinical groups, normative modeling identified 32 (22%) individuals with deviant PBSI-CT, 12 (8.4%) with deviant PBSI-SA, and 21 (15%) with deviant PBSI-SV; differences of small effect size indicated that individuals with deviant PBSI scores had lower IQ and higher psychopathology.; Examination of brain structural variability in early psychosis indicated heterogeneity at the level of individual profiles and encourages further large-scale examination to identify individuals that deviate markedly from normative reference data

Cortical thickness across the lifespan: Data from 17,075healthy individuals aged 3–90 years

Delineating the association of age and cortical thickness in healthy individuals is criti-cal given the association of cortical thickness with cognition and behavior. Previousresearch has shown that robust estimates of the association between age and brainmorphometry require large-scale studies. In response, we used cross-sectional datafrom 17,075 individuals aged 3–90 years from the Enhancing Neuroimaging Geneticsthrough Meta-Analysis (ENIGMA) Consortium to infer age-related changes in corticalthickness. We used fractional polynomial (FP) regression to quantify the associationbetween age and cortical thickness, and we computed normalized growth centilesusing the parametric Lambda, Mu, and Sigma method. Interindividual variability wasestimated using meta-analysis and one-way analysis of variance. For most regions,their highest cortical thickness value was observed in childhood. Age and corticalthickness showed a negative association; the slope was steeper up to the thirddecade of life and more gradual thereafter; notable exceptions to this general patternwere entorhinal, temporopolar, and anterior cingulate cortices. Interindividual vari-ability was largest in temporal and frontal regions across the lifespan. Age and its FPcombinations explained up to 59% variance in cortical thickness. These results mayform the basis of further investigation on normative deviation in cortical thicknessand its significance for behavioral and cognitive outcomes.Instituto de Salud Carlos III PI02049