107 research outputs found

    A universal mechanism for long-range cross-correlations

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    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

    Facilitators of implementing occupation based practice among Iranian occupational therapists: A qualitative study

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    Background: The Occupation-Based Practice (OBP) is a central core of occupational therapy (OT).It refers to using a meaningful occupation based on the client's interests, needs, health and participation in daily life. This study aimed to explore the facilitators of implementing OBP among Iranian occupational therapists. Methods: Fourteen occupational therapists participated in this study. Data were collected through semi-structured interviews, and the sampling method was purposeful. The interviews were continued until data saturation was reached, and data were recorded and transcribed verbatim. Data were analyzed through qualitative content analysis using constant comparative analysis. Results: Our analysis explored two themes: Factors attributed to context, and factors attributed to therapists. The first theme consisted of three subthemes: Educational programs of OT department, public information about OBP and clinical setting compatible with OBP. The second theme also contained three subthemes including: Positive attitude regarding effectiveness of OBP, emphasis on client- centered and family- centered practice and convincing the clients to utilize OBP. Conclusion: The facilitators of implementing OBP are attributed to factors internal to the therapists as well as to issues in the external environment and context. Understanding these factors will help occupational therapists, OT educational staff, administrators and rehabilitation team members to facilitate the implementation of OBP

    Prevalence of Psychiatric Symptoms and Mental Health Services in Students with Specific Learning Disabilities in Tehran, Iran

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    Children with specific learning disabilities are at a greater risk of mental health problems than their non-disabled peers. Further interventions and research will be required. This is a cross-sectional study. A sample of 107 students (7 to 11 years old) with specific learning disabilities were randomly selected from educational and rehabilitation settings in Tehran. The Child Symptom Inventory-4 (CSI-4) (parent checklist) was administered. Among children studied, 86 subjects (82.8 %) in some of the categories of psychiatric symptoms gained scores above the cut-off point. The most prevalent psychiatric symptoms were related to attention-deficit/hyperactivity disorder, generalized anxiety disorder and oppositional defiant disorder. There were not any statistically significant differences between the genders. In addition to direct education, 15 subjects (14 %) were receiving medication, 2 subjects (1.9 %) were receiving only occupational therapy, 2 subjects (1.9 %) were receiving only speech therapy, and 5 subjects (4.7 %) were receiving both occupational and speech therapy. The emphasis on considering co-morbid symptoms and usage of mental health services are important issues for students with specific learning difficulties

    Thin Film Tin Selenide (SnSe) Thermoelectric Generators Exhibiting Ultralow Thermal Conductivity

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    Tin selenide (SnSe) has attracted much attention in the field of thermoelectrics since the discovery of the record figure of merit (ZT) of 2.6 ± 0.3 along the b‐axis of the material. The record ZT is attributed to an ultralow thermal conductivity that arises from anharmonicity in bonding. While it is known that nanostructuring offers the prospect of enhanced thermoelectric performance, there have been minimal studies in the literature to date of the thermoelectric performance of thin films of SnSe. In this work, preferentially orientated porous networks of thin film SnSe nanosheets are fabricated using a simple thermal evaporation method, which exhibits an unprecedentedly low thermal conductivity of 0.08 W m−1 K−1 between 375 and 450 K. In addition, the first known example of a working SnSe thermoelectric generator is presented and characterized

    Strategic crossing of biomass and harvest index—source and sink—achieves genetic gains in wheat

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    To accelerate genetic gains in breeding, physiological trait (PT) characterization of candidate parents can help make more strategic crosses, increasing the probability of accumulating favorable alleles compared to crossing relatively uncharacterized lines. In this study, crosses were designed to complement “source” with “sink” traits, where at least one parent was selected for favorable expression of biomass and/or radiation use efficiency—source—and the other for sink-related traits like harvest-index, kernel weight and grains per spike. Female parents were selected from among genetic resources—including landraces and products of wide-crossing (i.e. synthetic wheat)—that had been evaluated in Mexico at high yield potential or under heat stress, while elite lines were used as males. Progeny of crosses were advanced to the F4 generation within Mexico, and F4-derived F5 and F6 generations were yield tested to populate four international nurseries, targeted to high yield environments (2nd and 3rd WYCYT) for yield potential, and heat stressed environments (2nd and 4th SATYN) for climate resilience, respectively. Each nursery was grown as multi-location yield trials. Genetic gains were achieved in both temperate and hot environments, with most new PT-derived lines expressing superior yield and biomass compared to local checks at almost all international sites. Furthermore, the tendency across all four nurseries indicated either the superiority of the best new PT lines compared with the CIMMYT elite checks, or the superiority of all new PT lines as a group compared with all checks, and in some cases, both. Results support—in a realistic breeding context—the hypothesis that yield and radiation use efficiency can be increased by improving source:sink balance, and validate the feasibility of incorporating exotic germplasm into mainstream breeding efforts to accelerate genetic gains for yield potential and climate resilience

    A pragmatic continuum level model for the prediction of the onset of keyholing in laser powder bed fusion

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    Laser powder bed fusion (L-PBF) is a complex process involving a range of multi-scale and multi-physical phenomena. There has been much research involved in creating numerical models of this process using both high and low fidelity modelling approaches where various approximations are made. Generally, to model single lines within the process to predict melt pool geometry and mode, high fidelity computationally intensive models are used which, for industrial purposes, may not be suitable. The model proposed in this work uses a pragmatic continuum level methodology with an ablation limiting approach at the mesoscale coupled with measured thermophysical properties. This model is compared with single line experiments over a range of input parameters using a modulated yttrium fibre laser with varying power and line speeds for a fixed powder layer thickness. A good trend is found between the predicted and measured width and depth of the tracks for 316L stainless steel where the transition into keyhole mode welds was predicted within 13% of experiments. The work presented highlights that pragmatic reduced physics-based modelling can accurately capture weld geometry which could be applied to more practical based uses in the L-PBF process

    Significant pathological findings in routine urethrocystoscopy before open prostatectomy

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    Background: Over the years, Trans Urethral Resection of Prostate (TURP), as a treatment modality for obstructing benign prostatic hyperplasia (BPH), gained popularity throughout the world. It is considered the gold standard for the surgical management of BPH. However, there is not the same pattern in our country and open prostatectomy is more common. Specific evaluation should be done preoperatively. Cystoscopy is one of them that have special limited indications. The aim of this study was to define the rate of pathological findings in routine urethrocystoscopy before open prostatectomy.Methods: In a prospective study from 2003 to 2005 in Dr Shariati hospital 120 patients prepared for open prostatectomy underwent routine cystoscopy, without absolute indications for cystoscopy.Results: There was no special pathology observed in routine cystoscopy. The results of this study revealed that the mean of age in patients with meatal stricture was significantly lower than those without stricture (59.5±0.7 vs. 49.9±5.5 years, p=0.008). Also, the results of present study showed that in patients with meatal stricture serum creatinine level was significantly higher (2.2±1.34 vs. 1.2±0.42 mgr/dL, p=0.003). Furthermore, it was revealed that the mean of age in patients with bladder diverticulum was significantly higher compared with those without bladder diverticulum (76.3±3.1 vs. 68.4±4.9 years, p=0.001).Conclusion: Routine cystoscopy is not necessary before open prostatectom

    Comparison and Relationships Between Social Support and Coping Strategies in Patients with Myocardial Infarction and in the Control Groups

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    Introduction: Heart diseases involve the first and most prevalent causes of morbidity as well as mortality in Iran, which can be affected by various factors. Hence, this study aimed to explore the comparison and relationships between social support and coping strategies in patients with myocardial infarction and in the control group in Rasht. Methods: In this descriptive study, the study healthy population consisted of all males aged 40-90 living in Rasht, among which 125 males were selected via a cluster random sampling method in 2013. Moreover, the study patient population entailed all male patients suffering from myocardial infarction aged 40-90 living in Rasht who were hospitalized in Dr.Heshmat hospital of Rasht in the first five months of 2013. The patient samples were 125 men selected via purposeful sampling method. In order to glean the study data, Carver's coping strategies inventory and Phillips' perceived social support questionnaire were applied and the data were analyzed utilizing SPSS software (Version 18). Results: The study results revealed that a significant correlation was observed between social support and problem-focused coping strategies in healthy subjects as well as in patients diagnosed with myocardial infarction. Furthermore, a significant difference was observed between healthy subjects and those suffering from myocardial infarction in regard with the overall score of perceived social support, emotion-focused coping strategies and problem-focused coping strategies. Conclusion: The findings of the current study demonstrated the role of social support variables and stress coping strategies should be taken into account in order to prevent cardiovascular diseases

    Predictive Risk Factors of Adverse Perinatal Outcomes Following Blunt Abdominal Trauma in Pregnancy

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    BACKGROUND: The primary objective was to identify predictive risk factors of preterm delivery following blunt abdominal trauma. The secondary objective was to identify risk factors of other adverse outcomes, Neonatal Intensive Care Unit (NICU) admission, placental abruption, fetal demise, and Cesarean Delivery (CD). METHODS: This retrospective study included pregnant patients with gestational age (GA) ≥23 weeks who presented after blunt abdominal trauma to Richmond University Medical Center from October 2015 to January 2020. Patients were identified using the following diagnostic International diagnostic classification (ICD-10) codes: O9A.212, O9A.213, and 071.89, and excluded if trauma did not involve the abdomen, penetrating, \u3c23 weeks, or incomplete records. Collected data points included maternal demographic factors, clinical laboratory values, maternal clinical findings at presentation, abdominal ultrasound, results of fetal monitoring, Abbreviated Injury Score (AIS) for abdomen, and Injury Severity Score (ISS). Univariate analyses were compared using the Student\u27s -test or Mann-Whitney -test. Categorical data were compared using the chi-squared test or Fisher\u27s exact test with -value \u3c .05 as significant. RESULTS: 154 patients were included in the final analysis. The incidence of the primary outcome, preterm delivery before 37 weeks, was 11.0% (17/154). The incidence of secondary outcomes following blunt abdominal trauma were abruption 0% (0/154), fetal demise 0.6% (1/154), CD 44% (68/154), NICU admission 24% (37/154). Maternal demographic factors, presence of uterine contractions, maternal clinical conditions (abdominal pain, abdominal tenderness, vaginal bleeding), hematologic and coagulation studies, ultrasound findings, fetal heart rate tracing category, AIS score for abdomen, and ISS score were not predictive of preterm delivery or other secondary outcomes. CONCLUSION: The incidence of adverse maternal and neonatal outcomes is low following blunt abdominal trauma. Extended monitoring of asymptomatic patients including laboratory tests and coagulation profiles were not predictive of preterm labor or secondary adverse perinatal outcomes. LEVEL OF EVIDENCE: Therapeutic/Care management, Level III

    Thromboangiitis obliterans episode: autoimmune flare-up or reinfection?

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    Mehran Mohareri,1 Ali Mirhosseini,1 Saeedeh Mehraban,1 Bahare Fazeli1,2 1Immunology Research Center, Inflammation and Inflammatory Diseases Division, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; 2Vascular Independent Research and Education, European Foundation, Milan, Italy Background: The possible role of infectious pathogens in the development of thromboangiitis obliterans (TAO) was considered soon after the disease was first described. However, it is not yet known whether infectious pathogens induce thrombotic vasculitis or if they cause a type of autoimmune disease. To investigate whether TAO relapses are more likely due to reinfection or autoimmune flare, the serum levels of toll-like receptor (sTLR) 4, sTLR2, C-reactive protein (CRP), and neopterin were evaluated in TAO patients during both the acute and quiescent phases of the disease as well as in a gender-, age-, and smoking habit-matched control group. Methods: Following a cross-sectional study design, 28 patients in the acute phase of TAO and 23 patients in the quiescent phase participated in this study. In addition, 31 matched controls were enrolled. Results: Toll-like receptor (TLR) 4 was significantly higher in patients in the acute phase of the disease than in patients in the quiescent phase (P=0.012). Also, TLR4 was significantly higher in the patients with CRP >7 µm/mL than in the patients with lower CRP (P=0.031). Notably, TLR4 in the patients in the quiescent phase of TAO was significantly lower than in the controls (P=0.006). No significant difference in the level of TLR2 was found among the groups (P>0.05). Neopterin was significantly higher in the acute phase of TAO in comparison to the quiescent phase (P=0.003) and the controls (P=0.005). Conclusion: These findings indicate that the trigger of TAO might be Gram-negative bacteria, which can be hidden or immunologically suppressed in the quiescent phase of TAO, leading to a lower level of TLR4 accompanying the normal level of neopterin. However, relapses might develop according to toxic or hypoxic cell injuries. Hence, TLR4 shedding will increase, and therefore, sTLR4 could become closer to the level demonstrated in the controls. Keywords: thromboangiitis obliterans, Buerger’s disease, TLR2, TLR4, neopterin, CRP, peripheral arterial diseases, vasculitis, innate immunity, infectio
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