Transformation cost spectrum for irregularly sampled time series

Irregularly sampled time series analysis is a common problem in various disciplines. Since conventional methods are not directly applicable to irregularly sampled time series, a common interpolation approach is used; however, this causes data distortion and consequently biases further analyses. We propose a method that yields a regularly sampled time series spectrum of costs with minimum information loss. Each time series in this spectrum is a stationary series and acts as a difference filter. The transformation costs approach derives the differences between consecutive and arbitrarily sized segments. After obtaining regular sampling, recurrence plot analysis is performed to distinguish regime transitions. The approach is applied to a prototypical model to validate its performance and to different palaeoclimate proxy data sets located around Africa to identify critical climate transition periods during the last 5 million years and their characteristic properties.Comment: 18 pages, 8 figures. Eur. Phys. J. Spec. Top. (2022

Türkiye'de ülke içinde yerinden edilme sorunu: tespitler ve çözüm önerileri = The problem of internal displacement in Turkey: assessment and policy proposals

Bu rapor, Doç. Dr. A. Tamer Aker (psikiyatr, Kocaeli Üniversitesi), Yrd. Doç. Dr. A. Betül Çelik (siyaset bilimci, Sabancı Üniversitesi), Dilek Kurban (hukuk doktoru, TESEV), Doç. Dr. Turgay Ünalan (nüfusbilimci, Hacettepe Üniversitesi) ve Yrd. Doç. Dr. H. Deniz Yükseker'den (sosyolog, Koç Üniversitesi) oluşan TESEV Ülke İçinde Yerinden Edilme Araştırma ve İzleme Grubu tarafından hazırlanmıştır. Grup, yerinden edilmeyi çatışma ortamının keskinleştirdiği devlet merkezli düşünüşün ve çeşitli ideolojik kamplaşmaların ötesinde, yurttaşlık haklarının yeniden tesisi ve toplumsal rehabilitasyon eksenlerinde ve insani boyutları bağlamında ele almaktadır

Recursive Estimation of User Intent from Noninvasive Electroencephalography using Discriminative Models

We study the problem of inferring user intent from noninvasive electroencephalography (EEG) to restore communication for people with severe speech and physical impairments (SSPI). The focus of this work is improving the estimation of posterior symbol probabilities in a typing task. At each iteration of the typing procedure, a subset of symbols is chosen for the next query based on the current probability estimate. Evidence about the user's response is collected from event-related potentials (ERP) in order to update symbol probabilities, until one symbol exceeds a predefined confidence threshold. We provide a graphical model describing this task, and derive a recursive Bayesian update rule based on a discriminative probability over label vectors for each query, which we approximate using a neural network classifier. We evaluate the proposed method in a simulated typing task and show that it outperforms previous approaches based on generative modeling.Comment: 5 pages, 2 figure

Radiological, biomechanical and histopathological characteristics of rat brain in Kaolin-induced hydrocephalus

Objective: A better understanding of the pathophysiology and underlying mechanisms of brain damage in hydrocephalus is vital in developing diagnostic, observational and treatment tools that will have an impact on hydrocephalus outcomes. In this study, we aimed to demonstrate the radiological, biomechanical and histopathological characteristics of rat brain tissue in an experimental hydrocephalus model. Materials and Methods: Thirty-six male Sprague-Dawley rats (21 days old, weighing between 150 and 200 grams) were used in this study. Animals were randomly assigned to control (n = 6), 1-week hydrocephalus (n = 10), 2-week hydrocephalus (n = 10) and 3-week hydrocephalus (n = 10) groups. Hydrocephalus was induced with cisternal kaolin injection and controls received sham injection. Magnetic resonance imaging was used to measure ventricle size and cortical thickness. Vital signs, cerebral blood flow (CBF), mechanical tests and brain histology were assessed. Results: Three rats in the hydrocephalus group died during the follow-up, yielding an overall mortality of 10% among animals from hydrocephalus groups. Ventricular width, cross-sectional area of the lateral ventricles, ventricular index and ventricle / brain area ratio progressively increased and cortical thickness progressively decreased following kaolin injection. CBF was significantly lower at baseline than at 1st, 2nd and 3rd week (p < 0.05, for all). ICP was significantly elevated in all hydrocephalic groups in comparison with controls. EIT that was calculated from the first load-unload indentation test showed a significant increase at 2nd week post-injection (p=0.0001), indicating increased intracranial stiffness. However, this significant difference disappeared at 3rd week (p=0.956). Quantitative immunohistochemistry showed that hydrocephalic brains demonstrated significantly less NeuN-positive cells and significantly higher IBA-1-positive microglia and glial fibrillary acidic protein positive astrocytes cells in the cortex. Discussion and Conclusion: Cisternal kaolin injection causes varying degrees of ventricular enlargement in a rat model and hydrocephalus might contribute to neuronal and axonal damage and alter brain stiffness through axonal stretching or local hypoperfusion progressively over a period of days to months. As shown in this study, irreversible changes in viscoelastic behaviour and cellular structure develop in the late stages of hydrocephalus, suggesting the importance of early intervention in the treatment of hydrocephalus

Improved arterial stiffness in mitral stenosis after successful percutaneous balloon valvuloplasty

Background: Rheumatic mitral stenosis (MS) is still a common disease in developing countries with high morbidity and mortality rates. The purpose of the study was to evaluate arterial stiffness in severe MS before and after percutaneous mitral balloon valvuloplasty (PMBV). Methods: Thirty patients with MS in sinus rhythm requiring PMBV and 20 age-gender matched healthy volunteers. The analyze of pulse wave velocities (PWV) were performed using of the carotid artery at the femoral by PWV technique on patients at baseline and a week after PMBV. Results: The values of PWV were significantly decreased after successful PMBW in MS patients. Mitral mean gradients and systolic pulmonary artery pressures (sPAP) both on echocardiography and catheterization also had a significant decrease after PMBW. The mitral valve areas were significantly increased after PMBW. There was a highly significant negative correlation between mitral valve areas and PWV values. A highly significant positive correlation was seen between mitral mean gradient on catheterization and PWV (r = 0.830, p < 0.001). There was also a significant correlation between sPAP on catheterization and PWV values (r = 0.639, p < 0.001). Echocardiographic mitral mean gradients and PWV were highly positive correlated with each other (r = 0.841, p < 0.001). The sPAP on echocardiography had also a highly positive correlation with PWV (r = 0.681, p < 0.001). Conclusions: Mitral stenosis is a cause of impaired arterial stiffness and after the enlargened mitral valve area arterial stiffness improved in patients with MS

User Training with Error Augmentation for Electromyogram-based Gesture Classification

We designed and tested a system for real-time control of a user interface by extracting surface electromyographic (sEMG) activity from eight electrodes in a wrist-band configuration. sEMG data were streamed into a machine-learning algorithm that classified hand gestures in real-time. After an initial model calibration, participants were presented with one of three types of feedback during a human-learning stage: veridical feedback, in which predicted probabilities from the gesture classification algorithm were displayed without alteration, modified feedback, in which we applied a hidden augmentation of error to these probabilities, and no feedback. User performance was then evaluated in a series of minigames, in which subjects were required to use eight gestures to manipulate their game avatar to complete a task. Experimental results indicated that, relative to baseline, the modified feedback condition led to significantly improved accuracy and improved gesture class separation. These findings suggest that real-time feedback in a gamified user interface with manipulation of feedback may enable intuitive, rapid, and accurate task acquisition for sEMG-based gesture recognition applications.Comment: 10 pages, 10 figure

Use of Complementary and Alternative Medicine Practices in Patients Admitted to The Pediatric Neurology Outpatient Clinic

Introduction: Despite the developments in pharmacologic treatments, traditional and complementary therapies have recently gained popularity in our country, as well as around the world. Aim: To question complementary and alternative medicine practices CAMP during clinical visits of pediatric neurology patients, to raise awareness of families and patients about the use of complementary and alternative medicine, and to prevent possible negative interactions. Methods: This prospective survey study was conducted with the parents of 300 pediatric patients aged between 6 months and 18 years, who were being treated at the Child Neurology Clinic between March 1st and May 30th, 2020. For the study, 360 patients’ parents who came to the Pediatric Neurology clinic for treatment were randomly selected, and a face-to-face survey lasting 2 minutes was conducted with 300 patients’ parents who agreed to participate in the study. This study was approved with the decision number E-20-12-62 at the meeting dated 21.12.2020 of the Clinical Research Ethics Committee of SBU Ankara Dr Sami Ulus Gynecology and Childhood Health and Diseases Training and Research Hospital. Results: Three hundred parents (56% women) participated in the study. Just over half (55.3%) of the patients were followed up with a diagnosis of epilepsy, 56.6% of the parents stated that they had used traditional and complementary therapy methods before, 43.4% stated that they did not use it, 46.54% stated that they used prayer and 23,9% used vitamin methods, respectively. Conclusion: In neurologic diseases, parents use traditional and complementary therapies as treatment methods, creating an alternative to modern medicine. Families and patients should be informed by investigating the reasons and frequency of using traditional and complementary therapies, raising the awareness of parents, and determining the possible harm caused by traditional and complementary therapies

A Prospective Study of Etiology of Childhood Acute Bacterial Meningitis, Turkey

Vaccines to prevent bacterial meningitis in this region must provide reliable protection against serogroup W-135