A universal mechanism for long-range cross-correlations

Cross-correlations are thought to emerge through interaction between particles. Here we present a universal dynamical mechanism capable of generating power-law cross-correlations between non-interacting particles exposed to an external potential. This phenomenon can occur as an ensemble property when the external potential induces intermittent dynamics of Pomeau-Manneville type, providing laminar and stochastic phases of motion in a system with a large number of particles. In this case, the ensemble of particle-trajectories forms a random fractal in time. The underlying statistical self-similarity is the origin of the observed power-law cross-correlations. Furthermore, we have strong indications that a sufficient condition for the emergence of these long-range cross-correlations is the divergence of the mean residence time in the laminar phase of the single particle motion (sporadic dynamics). We argue that the proposed mechanism may be relevant for the occurrence of collective behaviour in critical systems

The impact of chronic low back pain on daily occupations: A qualitative study in Iranian context

Objectives: Low back pain is one of the main health problems which affect many people worldwide. The daily course of life is highly disrupted due to the chronic back pain problem. This study aims to explore the occupational performance of individuals with chronic low back pain. Methods: Fifteen people with chronic low back pain were included in this study using purposeful sampling. The participants were interviewed, and a qualitative content analysis was employed to analyze the data. Results: The three main resulted themes were: 1) Occupational disturbance because of low back pain; 2) Difficulty in moving around and remaining in any given position; and 3) Permanent mind struggle owing to back pain. People with chronic low back pain experience difficulty in all areas of daily occupation including self-care, work, and leisure, plus having trouble with being physically active and being persistent in certain positions. Furthermore, mind struggle with back pain which implies preoccupation with back pain in addition to fear of movement are other findings of present study. Discussion: Chronic low back pain greatly influences the daily occupations of individuals. Mind struggle with back pain, which implies preoccupation with back pain, in addition to the fear of movement are significant findings of the present study. Occupational therapists can play an important role in re-engagement of people with chronic low back pain in their daily occupations

A computer-based selective visual attention test for first-grade school children: Design, development and psychometric properties

Background: Visual attention is known as a critical base for learning. The purpose of the present study was to design, develop and evaluate the test-retest and internal consistency reliability as well as face, content and convergent validity of the computer- based selective visual attention test (SeVAT) for healthy first-grade school children. Methods: In the first phase of this study, the computer-based SeVAT was developed in two versions of original and parallel. Ten experts in occupational therapy helped to measure the content validity using the CVR and CVI methods. Face validity was measured through opinions collected from 10 first-grade children. The convergent validity of the test was examined using the Spearman correlation between the SeVAT and Stroop test. In addition, test-retest reliability was determined by measuring the intra-class correlation (ICC) between the original and parallel versions of the SeVAT in a single session. The internal consistency was calculated by Cronbach's alpha coefficients. Sixty first grade children (30 girls/30boys) participated in this study. Results: The developed test was found to have good content and face validity. The SeVAT showed an excellent test-retest reliability (ICC= 0.778, p<0.001) and internal consistency (Cronbach's Alpha of original and parallel tests were 0.857 and 0.831, respectively). SeVAT and Stroop test demonstrated a positive correlation upon the convergent validity testing. Conclusion: Our results suggested an acceptable reliability and validity for the computer-based SeVAT in the assessment of selective attention in children. Further research may warrant the differential validity of such a test in other age groups and neuro-cognitively disordered populations

Recourse allocation in young and elderly adults

Objectives: The role of cognitive processes in postural control was shown in dual task studies. However, there was no definite evidence on how verbal instructions influence the allocation of attention to postural control. This study determined whether young and elderly adults are able to deliberately control the resource allocation when performing a sensorimotor and cognitive task simultaneously and if there are any differences between young and older adults in this regard. Method: A Cross-sectional study was performed in 16 young adults aged (23.95±3.31) and 20 elderly adults (61±2.21). Participants were selected by non-probable sampling method. Parallel standing and tandem standing on a hard surface were used as postural tasks. Force plate was used for postural performance. Postural sway was measured and the choice reaction time task was conducted as the cognitive task. Dual-task performance was measured under three different instructions including paying attention to the cognitive task, postural task, and equal attention to both tasks. Results: For postural performance the main effect of instructions and interactions by difficulty and groups were not significant (P�0.05) for cognitive performance. However, the main effect of group was significant (F=5.672, P=0.023), showing that elderly adults have longer reaction times. The interaction of instruction by group effect and also interaction of instruction by postural difficulty on mean reaction time was also significant, (F=3.710, P=0.030), (F=5.242, P=0.008) respectively . Discussion: Because of age related changes in the brain, flexibility in elderly adults are less than young adults

Occupational challenges in the caregivers of people with multiple sclerosis: A qualitative study

Background: Multiple Sclerosis (MS) is a neurodegenerative disorder. The progressive and unpredictable nature of MS indicates the patients� need for long-term care as well as the increased burden of their primary caregivers� care and occupational challenges that emerge in their daily life activities. Objectives: The current study aimed to explore the occupational challenges caused by engaging in the care process for the caregivers of people with MS Methods: This qualitative study was conducted on 21 caregivers of MS patients using a content analysis approach. Data were collected through semi-structured face-to-face interviews. Results: Three main themes emerged: Time limitations in occupation implementation, care needs in occupation implementation, and emotional reactions affecting occupations. Conclusions: According to the results, the caregivers of people with MS were faced with a variety of occupational challenges. The time limitations for performing routine occupations and desired activities, unmet patient care-facilitating needs, and the occurrence of psychosocial reactions and behaviors were contributed to these challenges and their exacerbation. Identifying these challenges is both useful for designing interventional programs and to help caregivers to successfully perform their desired occupations in spite of challenges in the care process. © 2020, Semnan University of Medical Sciences. All rights reserved

A survey on alzheimer�s disease detection using gait analysis

Introduction: Early detection of Alzheimer's disease (AD), as a neurodegenerative disease and the most common cause of dementia in the elderly people, using gait analysis have been particularly noted by researcher in recent years. Because this novel method is non-invasive, less cost, and feasible in non-clinical and laboratory environments. Therefore, in this Meta-Analysis review article, detection of AD using gait analysis based on information technology tools surveyed in previous studies. Materials and Methods: The search for previous articles was done in databases such as Google Scholar, Pubmed, IEEE, Springer, and Elsevier. After finding articles in these databases, appropriate articles were selected to survey based on criteria such as focusing of the study on elderly patients with AD or mild cognitive impairment, the detection and assessment of AD, and the use of sensor technology to record gait. Results: AD can be detected, even in the early stages and also at a stage of mild cognitive impairment based on gait analysis using new technologies with sensors and information technologies. Also, it is possible to quantitatively evaluate and more accurately detect the disease based on the combination of different sensor technologies and the use of artificial intelligence techniques. Conclusion: Although gait analysis can be a novel tool for early detection of AD, but it is essential to be developed and improved based on sensors and artificial intelligence in order to be used as a reliable clinical tools. © 2020, Semnan University of Medical Sciences. All rights reserved

Content validity of the comprehensive ICF core set for children with cerebral palsy aged 0-6 years: Iranian occupational therapists perspective

Objectives Comprehensive ICF Core Set of cerebral palsy (CP) includes a set of functions of children with CP has been created recently. This study determined the content validity of this version based on Iranian Occupational Therapists� perspectives to explore whether the ICF Core Sets for CP include the areas of function of CP in Occupational Therapy practice. Materials & Methods This qualitative study conducted from Feb 2015 to Apr 2016 in Tehran, Iran. Experts were the academic staffs selected through convenience sampling. Content validity of comprehensive ICF-Core Set of CP with 135 ICF categories was done by them. Delphi survey was used for generating consensus on the final version. Participants were 50 clinical Occupational Therapists invited via email from across Iran. An agreement of 75 was considered as the cut-off for inclusion of each code-category. Results About 60 of the code�categories of comprehensive version of ICF Core Set of CP were approved by Occupational Therapists. In the final version, 82 code-categories were listed that included 21 code-categories for Body Functions, 40 for Activity/Participation, and 21 for Environmental Factors. Conclusion The validity of the Iranian ICF Core Set for children with CP aged 0�6 yr was supported by Iranian Occupational Therapists. It could be the basis for evaluation of this population in Occupational Therapy. © 2018, Iranian Child Neurology Society. All rights reserved

Alveolar barrier disruption in varicella pneumonia is associated with neutrophil extracellular trap f

Primary varicella-zoster virus (VZV) infection in adults is often complicated by severe pneumonia, which is difficult to treat and is associated with high morbidity and mortality. Here, the simian varicella virus (SVV) nonhuman primate (NHP) model was used to investigate the pathogenesis of varicella pneumonia. SVV infection resulted in transient fever, viremia, and robust virus replication in alveolar pneumocytes and bronchus-associated lymphoid tissue. Clearance of infectious virus from lungs coincided with robust innate immune responses, leading to recruitment of inflammatory cells, mainly neutrophils and lymphocytes, and finally severe acute lung injury. SVV infection caused neutrophil activation and formation of neutrophil extracellular traps (NETs) in vitro and in vivo. Notably, NETs were also detected in lung and blood specimens of varicella pneumonia patients. Lung pathology in the SVV NHP model was associated with dysregulated expression of alveolar epithelial cell tight junction proteins (claudin-2, claudin-10, and claudin-18) and alveolar endothelial adherens junction protein VE-cadherin. Importantly, factors released by activated neutrophils, including NETs, were sufficient to reduce claudin-18 and VE-cadherin expression in NHP lung slice cultures. Collectively, the data indicate that alveolar barrier disruption in varicella pneumonia is associated with NET formation