Psikoloji Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/417

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  • Article
    Citation - WoS: 9
    Citation - Scopus: 10
    A Global Experience-Sampling Method Study of Well-Being During Times of Crisis: the Coco Project
    (Wiley, 2023) Reiter, Thomas; Sakel, Sophia; Horst, Julian ter; Geukes, Katharina; Gosling, Samuel D.; Back, Mitja D.; Scharbert, Julian; ter Horst, Julian
    We present a global experience-sampling method (ESM) study aimed at describing, predicting, and understanding individual differences in well-being during times of crisis such as the COVID-19 pandemic. This international ESM study is a collaborative effort of over 60 interdisciplinary researchers from around the world in the "Coping with Corona" (CoCo) project. The study comprises trait-, state-, and daily-level data of 7490 participants from over 20 countries (total ESM measurements = 207,263; total daily measurements = 73,295) collected between October 2021 and August 2022. We provide a brief overview of the theoretical background and aims of the study, present the applied methods (including a description of the study design, data collection procedures, data cleaning, and final sample), and discuss exemplary research questions to which these data can be applied. We end by inviting collaborations on the CoCo dataset.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 13
    Sleep, Sleep Spindles, and Cognitive Functions in Drug-Naive Patients With First-Episode Psychosis
    (Amer Acad Sleep Medicine, 2020) Yazihan, Naksidil Torun; Yetkin, Sinan
    Study Objectives: Various lines of clinical findings have suggested abnormalities in macro- or microstructural parameters of sleep in patients with schizophrenia. Meanwhile findings are inconclusive due to some confounding factors, such as the heterogeneity of the disorder, drug regimen, and duration of the illness. There are a few studies in the literature that have been conducted on drug-free patients with first-episode psychosis (FEP). Based on this knowledge, we aimed to explore sleep characteristics, sleep spindles, and neuropsychological profiles of the drug-naive patients with FEP. Methods: The study sample consisted of 21 drug-naive patients with FEP and 21 healthy participants. Polysomnography recordings were conducted for 2 subsequent nights. A neuropsychological test battery was administered for assessing cognitive functions. The Positive and Negative Syndrome Scale was applied to measure symptom severity of the patients. Spindle detection was performed visually. Results: According to the results of the study, the patient group's percentage of stage N2 sleep and sleep efficiency index was lower than in the control group. Among sleep spindle parameters, spindle density was found to be reduced in the patient group. The results of neuropsychological tests measuring executive functions, learning, and memory support the idea that there is a global cognitive deterioration from the early course of the disorder. In the psychotic group, negative symptoms were negatively correlated with verbal memory, learning, verbal fluency, and semantic organization. We found that the percentage of stage N3 sleep decreased while negative symptom severity increased. In addition, the percentage of stage N1 sleep increased as negative symptom severity increased. Reduction in stage N3 sleep was associated with an impairment in learning, verbal fluency, and response inhibition. The sleep spindle density and cognitive functions did not show any associations. Conclusions: Taken together, these findings suggest that patients with FEP show global cognitive impairment (except for attention and processing speed), which is associated with changes in sleep architecture and higher score in a scale assessing negative symptoms. We conclude that cognitive function and spindle parameters differ nonlinearly among patients with FEP.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Quadruple Fixed Point Theorems for Nonlinear Contractions on Partial Metric Spaces
    (Univ Politecnica Valencia, Editorial Upv, 2014) Karapinar, Erdal; Tas, Kenan
    The notion of coupled fixed point was introduced by Guo and Laksmikantham [12]. Later Gnana Bhaskar and Lakshmikantham in [11] investigated the coupled fixed points in the setting of partially ordered set by defining the notion of mixed monotone property. Very recently, the concept of tripled fixed point was introduced by Berinde and Borcut [7]. Following this trend, Karapmar[19] defined the quadruple fixed point. In this manuscript, quadruple fixed point is discussed and some new fixed point theorems are obtained on partial metric spaces.
  • Article
    Citation - WoS: 18
    Citation - Scopus: 24
    Fusion of Smartphone Sensor Data for Classification of Daily User Activities
    (Springer, 2021) Ozcelik, Erol; Misra, Sanjay; Damasevicius, Robertas; Maskeliunas, Rytis; Sengul, Gokhan
    New mobile applications need to estimate user activities by using sensor data provided by smart wearable devices and deliver context-aware solutions to users living in smart environments. We propose a novel hybrid data fusion method to estimate three types of daily user activities (being in a meeting, walking, and driving with a motorized vehicle) using the accelerometer and gyroscope data acquired from a smart watch using a mobile phone. The approach is based on the matrix time series method for feature fusion, and the modified Better-than-the-Best Fusion (BB-Fus) method with a stochastic gradient descent algorithm for construction of optimal decision trees for classification. For the estimation of user activities, we adopted a statistical pattern recognition approach and used the k-Nearest Neighbor (kNN) and Support Vector Machine (SVM) classifiers. We acquired and used our own dataset of 354 min of data from 20 subjects for this study. We report a classification performance of 98.32 % for SVM and 97.42 % for kNN.
  • Article
    Citation - WoS: 31
    Citation - Scopus: 32
    Oral Trail Making Task as a Discriminative Tool for Different Levels of Cognitive Impairment and Normal Aging
    (Oxford Univ Press, 2013) Bastug, G.; Ozel-Kizil, E. T.; Sakarya, A.; Altintas, O.; Kirici, S.; Altunoz, U.
    The Trail Making Test (TMT) is a useful measure of executive dysfunction in elderly subjects. This study aims to investigate the discriminative validity of the oral version of the TMT (OTMT), which can be administered to subjects with visual or motor disabilities, in elderly patients with Mild Cognitive Impairment (MCI; n = 30), Alzheimer's disease (AD; n = 30), and healthy controls (HCs; n = 25). The WAIS-R Digit Span Backwards Subscale, written form of the Trail Making Task, the Clock Drawing Test, the AD Assessment Scale-Cognitive Subscale, and the OTMT were also administered to all participants in order to examine the concurrent validity of the OTMT. The OTMT part B discriminated between patients with MCI, AD, and HC correctly. The OTMT completion time was not correlated with age, but was negatively correlated with education. In conclusion, the OTMT (mostly part B) is a valid and practical measurement tool for different levels of cognitive impairment, especially for patients with visual or motor disabilities for whom the classical written form is not feasible.