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Sample records for 10-week randomized hypo-energetic

  1. Macronutrient-specific effect of FTO rs9939609 in response to a 10-week randomized hypo-energetic diet among obese Europeans

    Grau, K; Hansen, Torben; Holst, C;

    2009-01-01

    -energetic diet (measured resting metabolic rate multiplied by 1.3-600 kcal day(-1)). Body weight, fat mass (FM), fat-free mass (FFM), waist circumference (WC), resting energy expenditure (REE), fasting fat oxidation as % of REE (FatOx), insulin release (HOMA-beta) and a surrogate measure of insulin resistance...... found no effect of FTO rs9939609 genotype on Deltaweight, DeltaFM, DeltaFFM, DeltaWC or DeltaFatOx. However, participants with TT had a smaller reduction in REE on LF than on HF diet (75 kcal/24 h; interaction: P=0.0055). These individuals also showed the greatest reduction in HOMA-beta and HOMA......BACKGROUND: The A risk allele of rs9939609 of the fat mass- and obesity-associated gene (FTO) increases body fat mass. OBJECTIVE: To examine whether FTO rs9939609 affects obese individuals' response to a high-fat, low-carbohydrate (CHO) (HF) or low-fat, high-CHO (LF), hypo-energetic diet and...

  2. Lithium trial in Alzheimer's disease: a randomized, single-blind, placebo-controlled, multicenter 10-week study.

    Hampel, Harald

    2012-02-01

    OBJECTIVE: Lithium, a first-line drug for the treatment of bipolar depression, has recently been shown to regulate glycogen synthase kinase-3 (GSK-3), a kinase that is involved in the phosphorylation of the tau protein. Since hyperphosphorylation of tau is a core pathological feature in Alzheimer\\'s disease, lithium-induced inhibition of GSK-3 activity may have therapeutic effects in Alzheimer\\'s disease. In the current study, we tested the effect of short-term lithium treatment in patients with Alzheimer\\'s disease. METHOD: A total of 71 patients with mild Alzheimer\\'s disease (Mini-Mental State Examination score > or = 21 and < or = 26) were successfully randomly assigned to placebo (N = 38) or lithium treatment (N = 33) at 6 academic expert memory clinics. The 10-week treatment included a 6-week titration phase to reach the target serum level of lithium (0.5-0.8 mmol\\/L). The primary outcome measures were cerebrospinal fluid (CSF) levels of phosphorylated tau (p-tau) and GSK-3 activity in lymphocytes. Secondary outcome measures were CSF concentration of total tau and beta-amyloid(1-42) (Abeta(1-42)), plasma levels of Abeta(1-42), Alzheimer\\'s Disease Assessment Scale (ADAS)-Cognitive summary scores, MMSE, and Neuropsychiatric Inventory (NPI). Patients were enrolled in the study from November 2004 to July 2005. RESULTS: No treatment effect on GSK-3 activity or CSF-based biomarker concentrations (P > .05) was observed. Lithium treatment did not lead to change in global cognitive performance as measured by the ADAS-Cog subscale (P = .11) or in depressive symptoms. CONCLUSIONS: The current results do not support the notion that lithium treatment may lead to reduced hyperphosphorylation of tau protein after a short 10-week treatment in the Alzheimer\\'s disease target population. TRIAL REGISTRATION: (Controlled-Trials.com) Identifier: ISRCTN72046462.

  3. Allelic variants of melanocortin 3 receptor gene (MC3R and weight loss in obesity: a randomised trial of hypo-energetic high- versus low-fat diets.

    José L Santos

    Full Text Available INTRODUCTION: The melanocortin system plays an important role in energy homeostasis. Mice genetically deficient in the melanocortin-3 receptor gene have a normal body weight with increased body fat, mild hypophagia compared to wild-type mice. In humans, Thr6Lys and Val81Ile variants of the melanocortin-3 receptor gene (MC3R have been associated with childhood obesity, higher BMI Z-score and elevated body fat percentage compared to non-carriers. The aim of this study is to assess the association in adults between allelic variants of MC3R with weight loss induced by energy-restricted diets. SUBJECTS AND METHODS: This research is based on the NUGENOB study, a trial conducted to assess weight loss during a 10-week dietary intervention involving two different hypo-energetic (high-fat and low-fat diets. A total of 760 obese patients were genotyped for 10 single nucleotide polymorphisms covering the single exon of MC3R gene and its flanking regions, including the missense variants Thr6Lys and Val81Ile. Linear mixed models and haplotype-based analysis were carried out to assess the potential association between genetic polymorphisms and differential weight loss, fat mass loss, waist change and resting energy expenditure changes. RESULTS: No differences in drop-out rate were found by MC3R genotypes. The rs6014646 polymorphism was significantly associated with weight loss using co-dominant (p = 0.04 and dominant models (p = 0.03. These p-values were not statistically significant after strict control for multiple testing. Haplotype-based multivariate analysis using permutations showed that rs3827103-rs1543873 (p = 0.06, rs6014646-rs6024730 (p = 0.05 and rs3746619-rs3827103 (p = 0.10 displayed near-statistical significant results in relation to weight loss. No other significant associations or gene*diet interactions were detected for weight loss, fat mass loss, waist change and resting energy expenditure changes. CONCLUSION: The study

  4. Randomized, multi-center trial of two hypo-energetic diets in obese subjects: high- versus low-fat content

    Petersen, M; Taylor, M A; Saris, W H M; Verdich, C; Toubro, Søren; Macdonald, I; Rössner, S; Stich, V; Guy-Grand, B; Langin, D; Martinez, J A; Pedersen, O; Holst, C; Sørensen, Thorkild I.A.; Astrup, Arne

    2006-01-01

    :Obese (BMI >or=30 kg/m(2)) adult subjects (n = 771), from eight European centers. MEASUREMENTS: Body weight loss, dropout rates, proportion of subjects who lost more than 10% of initial body weight, blood lipid profile, insulin and glucose. RESULTS: The dietary fat energy percent was 25% in the low-fat group...... and 40% in the high-fat group (mean difference: 16 (95% confidence interval (CI) 15-17)%). Average weight loss was 6.9 kg in the low-fat group and 6.6 kg in the high-fat group (mean difference: 0.3 (95% CI -0.2 to 0.8) kg). Dropout was 13.6% (n = 53) in the low-fat group and 18.3% (n = 70) in the high-fat...... group than in the high-fat group. Fasting plasma insulin and glucose were lowered equally by both diets. CONCLUSIONS: The low-fat diet produced similar mean weight loss as the high-fat diet, but resulted in more subjects losing >10% of initial body weight and fewer dropouts. Both diets produced...

  5. Rabies in a 10-week-old puppy.

    White, Jennifer; Taylor, Susan M; Wolfram, Kathrin L; O'Conner, Brendan P

    2007-09-01

    A 10-week-old, male, border collie-cross puppy was examined for an acute onset of unilateral vestibular signs. Neurologic deterioration was rapid over the next 12 hours and the puppy was euthanized. Rabies was diagnosed by histopathologic and immunohistochemical examination. PMID:17966334

  6. ADHD Symptom Severity following Participation in a Pilot, 10-Week, Manualized, Family-Based Behavioral Intervention

    Curtis, David F.

    2010-01-01

    This investigation examined the effectiveness of a pilot, manualized 10-week intervention of family skills training for ADHD-related symptoms. The intervention combined behavioral parent training and child focused behavioral activation therapy. Participants were families with children ages 7-10 diagnosed with ADHD-Combined Type. This pilot…

  7. Structural and functional cardiac adaptations to a 10-week school-based football intervention for 9-10-year-old children

    Krustrup, Peter; Hansen, Peter Riis; Nielsen, Claus Malta;

    2014-01-01

    The present study investigated the cardiac effects of a 10-week football training intervention for school children aged 9-10 years using comprehensive transthoracic echocardiography as a part of a larger ongoing study. A total of 97 pupils from four school classes were cluster-randomized into a c...... pressure. In conclusion, a short-term, school-based intervention comprising small-sided football sessions resulted in significant structural and functional cardiac adaptations in pre-adolescent children....

  8. Effect of 10 Week Beta-Alanine Supplementation on Competition and Training Performance in Elite Swimmers

    Louise M. Burke

    2012-10-01

    Full Text Available Although some laboratory-based studies show an ergogenic effect with beta-alanine supplementation, there is a lack of field-based research in training and competition settings. Elite/Sub-elite swimmers (n = 23 males and 18 females, age = 21.7 ± 2.8 years; mean ± SD were supplemented with either beta-alanine (4 weeks loading phase of 4.8 g/day and 3.2 g/day thereafter or placebo for 10 weeks. Competition performance times were log-transformed, then evaluated before (National Championships and after (international or national selection meet supplementation. Swimmers also completed three standardized training sets at baseline, 4 and 10 weeks of supplementation. Capillary blood was analyzed for pH, bicarbonate and lactate concentration in both competition and training. There was an unclear effect (0.4%; ±0.8%, mean, ±90% confidence limits of beta-alanine on competition performance compared to placebo with no meaningful changes in blood chemistry. While there was a transient improvement on training performance after 4 weeks with beta-alanine (−1.3%; ±1.0%, there was an unclear effect at ten weeks (−0.2%; ±1.5% and no meaningful changes in blood chemistry. Beta-alanine supplementation appears to have minimal effect on swimming performance in non-laboratory controlled real-world training and competition settings.

  9. Effects of a 10-Week High-Intensity Exercise Intervention on College Staff with Psychological Burnout and Multiple Risk Factors

    Dreyer, Lukas; Dreyer, Sonja; Rankin, Dean

    2012-01-01

    This study examined the effect of a 10-week physical exercise program on the health status of college staff. Eighty-one participants were pre-tested on 22 variables including physical fitness, biochemical status, psychological health, and morphological measures. Participants in an experimental group (n = 61) received a 10-week intervention…

  10. Effect of 10-week core stabilization exercise training and detraining on pain-related outcomes in patients with clinical lumbar instability

    Puntumetakul R

    2013-11-01

    Full Text Available Rungthip Puntumetakul,1,2 Pattanasin Areeudomwong,1,2 Alongkot Emasithi,1 Junichiro Yamauchi3,4 1School of Physical Therapy, Faculty of Associated Medical Sciences, Muang District, Kohn Kaen, Thailand; 2Back, Neck and Other Joint Pain Research Group, Khon Kaen University, Khon Kaen, Thailand; 3Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan; 4Future Institute for Sport Sciences, Tokyo, Japan Background and aims: Clinical lumbar instability causes pain and socioeconomic suffering; however, an appropriate treatment for this condition is unknown. This article examines the effect of a 10 week core stabilization exercise (CSE program and 3 month follow-up on pain-related outcomes in patients with clinical lumbar instability. Methods: Forty-two participants with clinical lumbar instability of at least 3 months in duration were randomly allocated either to 10 weekly treatments with CSE or to a conventional group (CG receiving trunk stretching exercises and hot pack. Pain-related outcomes including pain intensity during instability catch sign, functional disability, patient satisfaction, and health-related quality of life were measured at 10 weeks of intervention and 1 and 3 months after the last intervention session (follow-up; trunk muscle activation patterns measured by surface electromyography were measured at 10 weeks. Results: CSE showed significantly greater reductions in all pain-related outcomes after 10 weeks and over the course of 3 month follow-up periods than those seen in the CG (P<0.01. Furthermore, CSE enhanced deep abdominal muscle activation better than in the CG (P<0.001, whereas the CG had deterioration of deep back muscle activation compared with the CSE group (P<0.01. For within-group comparison, CSE provided significant improvements in all pain-related outcomes over follow-up (P<0.01, whereas the CG demonstrated reduction in pain intensity during instability catch sign only at 10 weeks (P<0

  11. A 10-Week Multimodal Nutrition Education Intervention Improves Dietary Intake among University Students: Cluster Randomised Controlled Trial.

    Shahril, Mohd Razif; Wan Dali, Wan Putri Elena; Lua, Pei Lin

    2013-01-01

    The aim of the study was to evaluate the effectiveness of implementing multimodal nutrition education intervention (NEI) to improve dietary intake among university students. The design of study used was cluster randomised controlled design at four public universities in East Coast of Malaysia. A total of 417 university students participated in the study. They were randomly selected and assigned into two arms, that is, intervention group (IG) or control group (CG) according to their cluster. The IG received 10-week multimodal intervention using three modes (conventional lecture, brochures, and text messages) while CG did not receive any intervention. Dietary intake was assessed before and after intervention and outcomes reported as nutrient intakes as well as average daily servings of food intake. Analysis of covariance (ANCOVA) and adjusted effect size were used to determine difference in dietary changes between groups and time. Results showed that, compared to CG, participants in IG significantly improved their dietary intake by increasing their energy intake, carbohydrate, calcium, vitamin C and thiamine, fruits and 100% fruit juice, fish, egg, milk, and dairy products while at the same time significantly decreased their processed food intake. In conclusion, multimodal NEI focusing on healthy eating promotion is an effective approach to improve dietary intakes among university students. PMID:24069535

  12. A 10-Week Multimodal Nutrition Education Intervention Improves Dietary Intake among University Students: Cluster Randomised Controlled Trial

    Mohd Razif Shahril

    2013-01-01

    Full Text Available The aim of the study was to evaluate the effectiveness of implementing multimodal nutrition education intervention (NEI to improve dietary intake among university students. The design of study used was cluster randomised controlled design at four public universities in East Coast of Malaysia. A total of 417 university students participated in the study. They were randomly selected and assigned into two arms, that is, intervention group (IG or control group (CG according to their cluster. The IG received 10-week multimodal intervention using three modes (conventional lecture, brochures, and text messages while CG did not receive any intervention. Dietary intake was assessed before and after intervention and outcomes reported as nutrient intakes as well as average daily servings of food intake. Analysis of covariance (ANCOVA and adjusted effect size were used to determine difference in dietary changes between groups and time. Results showed that, compared to CG, participants in IG significantly improved their dietary intake by increasing their energy intake, carbohydrate, calcium, vitamin C and thiamine, fruits and 100% fruit juice, fish, egg, milk, and dairy products while at the same time significantly decreased their processed food intake. In conclusion, multimodal NEI focusing on healthy eating promotion is an effective approach to improve dietary intakes among university students.

  13. Impact of 10-weeks of yoga practice on flexibility and balance of college athletes

    Polsgrove, M Jay; Eggleston, Brandon M; Lockyer, Roch J

    2016-01-01

    Background: With clearer evidence of its benefits, coaches, and athletes may better see that yoga has a role in optimizing performance. Aims: To determine the impact of yoga on male college athletes (N = 26). Methods: Over a 10-week period, a yoga group (YG) of athletes (n = 14) took part in biweekly yoga sessions; while a nonyoga group (NYG) of athletes (n = 12) took part in no additional yoga activity. Performance measures were obtained immediately before and after this period. Measurements of flexibility and balance, included: Sit-reach (SR), shoulder flexibility (SF), and stork stand (SS); dynamic measurements consisted of joint angles (JA) measured during the performance of three distinct yoga positions (downward dog [DD]; right foot lunge [RFL]; chair [C]). Results: Significant gains were observed in the YG for flexibility (SR, P = 0.01; SF, P = 0.03), and balance (SS, P = 0.05). No significant differences were observed in the NYG for flexibility and balance. Significantly, greater JA were observed in the YG for: RFL (dorsiflexion, l-ankle; P = 0.04), DD (extension, r-knee, P = 0.04; r-hip; P = 0.01; flexion, r-shoulder; P = 0.01) and C (flexion, r-knee; P = 0.01). Significant JA differences were observed in the NYG for: DD (flexion, r-knee, P = 0.01: r-hip, P = 0.05; r-shoulder, P = 0.03) and C (flexion r-knee, P = 0.01; extension, r-shoulder; P = 0.05). A between group comparison revealed the significant differences for: RFL (l-ankle; P = 0.01), DD (r-knee, P = 0.01; r-hip; P = 0.01), and C (r-shoulder, P = 0.02). Conclusions: Results suggest that a regular yoga practice may increase the flexibility and balance as well as whole body measures of male college athletes and therefore, may enhance athletic performances that require these characteristics. PMID:26865768

  14. The Effects of a 10-Week Water Aerobic Exercise on the Resting Blood Pressure in Patients with Essential Hypertension

    Farahani

    2010-09-01

    Full Text Available Purpose To investigate the effects of a 10-week water aerobic exercise on the resting blood pressure in patients with stage 1 or 2 hypertension referring to Tehran University Clinics. Methods Forty men with stage 1 or 2 essential hypertension were assigned to two groups of intervention [n = 12; aged 48.33±10.74 years (mean±SD] and control [n = 28; aged 46.96±11.58 years (mean±SD]. Subjects in the intervention group participated in a supervised 10-week water aerobic training program of 55 min sessions, 3 days per week on alternate days, while those in the control group were not involved in any regular training program during this period. Blood pressure of the participants was recorded and compared at the beginning and at the end of the study (48 hours after the last training session. Results Exercise lowered systolic blood pressure and mean arterial pressure by 11.71 (95% confidence interval: 5.07 to 18.35 and 5.90 (95% confidence interval: 1.17 to 10.63 mm Hg respectively. The lowering effect of exercise on diastolic blood pressure was neither statistically significant nor clinically important (0.55 mm Hg; P. value = 0.8. There was no significant effect of age, baseline body mass index and stage of hypertension on the exercise-induced changes in blood pressure. Conclusion A 10-week course of water aerobic exercise markedly reduced the systolic and mean arterial blood pressure of patients with essential hypertension and is especially recommended for the obese and the elderly who have orthopedic problems or bronchospasm.

  15. Physical and psychological benefits of once-a-week Pilates exercises in young sedentary women: A 10-week longitudinal study.

    Tolnai, Nóra; Szabó, Zsófia; Köteles, Ferenc; Szabo, Attila

    2016-09-01

    Pilates exercises have several demonstrated physical and psychological benefits. To date, most research in this context was conducted with symptomatic or elderly people with few dependent measures. The current study examined the chronic or longitudinal effects of very low frequency, once a week, Pilates training on several physical and psychological measures, over a 10-week intervention, in young, healthy, and sedentary women. Further, the study gauged the acute effects of Pilates exercises on positive- and negative affect in 10 exercise sessions. Compared to a control group, the Pilates group exhibited significant improvements in skeletal muscle mass, flexibility, balance, core- and abdominal muscle strength, body awareness, and negative affect. This group also showed favorable changes in positive (22.5% increase) and negative affect (12.2% decrease) in nine out of ten exercise sessions. This work clearly demonstrates the acute and chronic benefits of Pilates training on both physical and psychological measures. It also reveals that even only once a week Pilates training is enough to trigger detectable benefits in young sedentary women. While this frequency is below the required levels of exercise for health, it may overcome the 'lack of time' excuse for not exercising and subsequently its tangible benefits may positively influence one's engagement in more physical activity. PMID:27195456

  16. Effects of 10-week eccentric overload training on kinetic parameters during change of direction in football players.

    de Hoyo, Moisés; Sañudo, Borja; Carrasco, Luis; Mateo-Cortes, Jesús; Domínguez-Cobo, Sergio; Fernandes, Orlando; Del Ojo, Juan J; Gonzalo-Skok, Oliver

    2016-07-01

    The aim of the current study was to analyse the effect of 10-week eccentric overload training on kinetic parameters during change of direction (COD) in U-19 football players. The outcome measured included relative peak braking (rPB) and propulsive force (rPF), contact time (CT), time spent during braking (BT) and propulsive phase (PT), relative total (rTOT_IMP), braking (rB_IMP) and propulsive (rP_IMP) impulses. Between-group results showed a substantial better improvement (likely) in CT (ES: 0.72) and BT (ES: 0.74) during side-step cutting, and in rPB (ES: 0.84) and rB_IMP (ES: 0.72) during crossover cutting, in the experimental group (EXP) in comparison to control group (CON). Within-group analysis showed a substantially better performance (likely to almost certain) in CT (ES: 1.19), BT (ES: 1.24), PT (ES: 0.70), rPB (ES: 0.75), rPF (ES: 0.68), rTOT_IMP (ES: 0.48) and rB_IMP (ES: 0.50) in EXP during side-step cutting. Regarding crossover cutting, within-group analysis showed a substantial better performance (likely to almost certain) in CT (ES: 0.75), rPB (ES: 0.75), rPF (ES: 1.34), rTOT_IMP (ES: 0.61), rB_IMP (ES: 0.76) and rP_IMP (ES: 0.46) in EXP. In conclusion, the eccentric overload-based programme led to an improvement in kinetic parameters during COD football tasks. PMID:26963941

  17. A 10-Week Multimodal Nutrition Education Intervention Improves Dietary Intake among University Students: Cluster Randomised Controlled Trial

    Mohd Razif Shahril; Wan Putri Elena Wan Dali; Pei Lin Lua

    2013-01-01

    The aim of the study was to evaluate the effectiveness of implementing multimodal nutrition education intervention (NEI) to improve dietary intake among university students. The design of study used was cluster randomised controlled design at four public universities in East Coast of Malaysia. A total of 417 university students participated in the study. They were randomly selected and assigned into two arms, that is, intervention group (IG) or control group (CG) according to their cluster. T...

  18. Tolerating Uncertainty: The Exploration of a 10-Week Stress Management Course which Supports a Process of Recovery, Personal Change and Educational Development for People Experiencing Stress and Anxiety.

    Smith, Sue

    2002-01-01

    A 10-week stress management and relaxation course helped anxious students develop skills and strategies derived from self-awareness. Course included stress theory, organizational skills (time management, goal setting), personal transformation, tolerance for uncertainty, and metacognition, with an emphasis on self-efficacy and autonomy. (Contains…

  19. A Comparison of Student Outcomes and Overall Retention between a 10-Week Accelerated and a 15-Week Traditional Curriculum in a Postsecondary Apprenticeship Training Program

    Adams, Gilbert L.

    2013-01-01

    This ex post facto comparison study of a postsecondary apprenticeship program at a naval ship construction company examined 8 years of academic performance and program completion data for two curricular formats: a 15-week traditional group (1,259 apprentices) and a 10-week accelerated group (736 apprentices). The two groups were investigated to…

  20. Impact of a 10-Week Individualized Exercise Program on Physical Function and Fatigue of People with Multiple Sclerosis: A Pilot Study

    Vore, Mary Ellen; Elgelid, Staffan; Bolger, Shannon; Parsons, Caroline; Quashnoc, Rachel; Raymor, Johanna

    2011-01-01

    Research has found that people with multiple sclerosis (MS) who engage in exercise programs experience improvements in physical and psychological health, resulting in enhanced quality of life. These studies have involved structured exercise protocols, but few have examined the effects of an individualized exercise program allowing for peer socialization. The purpose of this study was to investigate the effects of a 10-week individualized exercise program offering opportunities to socialize wi...

  1. The effects of 10 weeks of resistance training combined with beta-alanine supplementation on whole body strength, force production, muscular endurance and body composition.

    Kendrick, Iain P; Harris, Roger C; Kim, Hyo Jeong; Kim, Chang Keun; Dang, Viet H; Lam, Thanh Q; Bui, Toai T; Smith, Marcus; Wise, John A

    2008-05-01

    Carnosine (Carn) occurs in high concentrations in skeletal muscle is a potent physico-chemical buffer of H+ over the physiological range. Recent research has demonstrated that 6.4 g x day(-1) of beta-alanine (beta-ala) can significantly increase skeletal muscle Carn concentrations (M-[Carn]) whilst the resultant change in buffering capacity has been shown to be paralleled by significant improvements in anaerobic and aerobic measures of exercise performance. Muscle carnosine increase has also been linked to increased work done during resistance training. Prior research has suggested that strength training may also increase M-[Carn] although this is disputed by other studies. The aim of this investigation is to assess the effect of 10 weeks resistance training on M-[Carn], and, secondly, to investigate if increased M-[Carn] brought about through beta-ala supplementation had a positive effect on training responses. Twenty-six Vietnamese sports science students completed the study. The subjects completed a 10-week resistance-training program whilst consuming 6.4 g x day(-1) of beta-ala (beta-ALG) or a matched dose of a placebo (PLG). Subjects were assessed prior to and after training for whole body strength, isokinetic force production, muscular endurance, body composition. beta-Alanine supplemented subjects increased M-[Carn] by 12.81 +/- 7.97 mmol x kg(-1) dry muscle whilst there was no change in PLG subjects. There was no significant effect of beta-ala supplementation on any of the exercise parameters measured, mass or % body fat. In conclusion, 10 weeks of resistance training alone did not change M-[Carn]. PMID:18175046

  2. A 10-week memantine treatment in bipolar depression: a case report. Focus on depressive symptomatology, cognitive parameters and quality of life.

    Strzelecki, Dominik; Tabaszewska, Agnieszka; Barszcz, Zbigniew; Józefowicz, Olga; Kropiwnicki, Paweł; Rabe-Jabłońska, Jolanta

    2013-12-01

    Memantine and other glutamatergic agents have been currently investigated in some off-label indications due to glutamatergic involvement in several psychoneurological disorders. We assumed that memantine similarly to ketamine may positively influence mood, moreover having a potential to improve cognition and general quality of life. We report a case of a 49-year-old male hospitalized during a manic and a subsequent moderate depressive episode. After an ineffective use of lithium, olanzapine and antidepressive treatment with mianserin, memantine was added up to 20 mg per day for 10 weeks. The mental state was assessed using the Hamilton Depression Rating Scale, the Young Mania Rating Scale, the Hamilton Anxiety Scale, the Clinical Global Inventory, the World Health Organization Quality of Life Scale and psychological tests. After 10 weeks the patient achieved a partial symptomatic improvement in mood, anxiety and quality of sleep, but his activity remained insufficient. We also observed an improvement in the parameters of cognitive functioning and quality of life. There was neither significant mood variations during the memantine use nor mood changes after its termination. No significant side effects were noted during the memantine treatment. We conclude that using memantine in bipolar depression may improve mood, cognitive functioning and quality of life. PMID:24474993

  3. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period

    Burke DT

    2013-10-01

    Full Text Available David T Burke,1 David Tran,1 Di Cui,1 Daniel P Burke,2 Samir Al-Adawi,3 Atsu SS Dorvlo41Emory University Medical School, Atlanta, GA, USA; 2Georgia College and State University, GA, USA; 3Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; 4Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat, OmanAbstract: In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.Keywords: Anatoly Gravitational System, weight training, musculoskeletal system

  4. Metabolic and growth response of mink (Neovison vison) kits until 10 weeks of age when exposed to different dietary protein provision

    Larsson, Caroline; Fink, Rikke; Matthiesen, Connie Marianne Frank;

    2012-01-01

    weighed weekly, and were measured by means of balance experiment and indirect calorimetry, in weeks eight and nine post-partum (p.p.). At weaning (seven weeks p.p.) and 10 weeks p.p. one kit per litter was killed and blood, liver and kidneys were collected. Plasma amino acid profiles, and hepatic...... abundance of mRNA for phosphoenolpyruvate carboxykinase (PEPCK), fructose 1,6-biphosphatase, pyruvate kinase and glucose-6-phosphatase (G-6-Pase) by q-PCR, were determined. There were no differences in live weights among kits the first four weeks of life when kits solely consumed milk, but male LP kits were...... milk to solid feed. The capacity to regulate the rate of gluconeogenesis was even more limited in young mink kits than in adult dams. However, young mink kits can regulate protein oxidation in response to dietary protein supply, probably by adapting the size of the liver and kidneys to the level of...

  5. Change in proportional protein intake in a 10-week energy-restricted low- or high-fat diet, in relation to changes in body size and metabolic factors

    Stocks, Tanja; Taylor, Moira A; Ängquist, Lars;

    2013-01-01

    Objective: To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors. Methods: Obese adults (n = 771) were randomised to a 600 kcal...... increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet. Copyright © 2013 S. Karger GmbH, Freiburg....... energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (2) on outcomes...

  6. Augmentation of antipsychotics with glycine may ameliorate depressive and extrapyramidal symptoms in schizophrenic patients – a preliminary 10-week open-label study

    Strzelecki, Dominik

    2013-07-01

    Full Text Available Aim. The objective of this study was to analyze the changes in depressive and extrapyramidal symptomatology during glycine augmentation of antipsychotic treatment in patients with schizophrenia.Materials and methods. Twenty-nine schizophrenic patients (ICD-10 with predominant negative symptoms in stable mental state participated in a 10-week open-label prospective study. Patients received stable doses of antipsychotic drugs for at least 3 months before glycine application. During the next 6 weeks patients received augmentation of antipsychotic treatment with glycine (up to 60 g per day. The first and last two weeks of observation were used to assess stability of mental state. Symptom severity was assessed using the Hamilton Depression Rating Scale (HDRS, the Positive and Negative Syndrome Scale (PANSS, and the Simpson-Angus Extrapyramidal Symptom Rating Scale (SASResults. In the studied group after 6 weeks of administration of glycine a significant improvement in depressive symptoms (reduced scores by 25.8% in HDRS, p <0.001 and reduced scoring in mood symptoms of PANSS were observed. In SAS a reduction of extrapyramidal symptoms’ severity (p <0.05 was also noted. Two weeks after the glycine augmentation the symptom severity in the HDRS, PANSS, and SAS remained at similar levels.Conclusions. Glycine augmentation of antipsychotic treatment may reduce the severity of depressive and extrapyramidal symptoms. Glycine use was safe and well tolerated.

  7. Place-based research project design for 10-week REU and two-week "mini-REU" internships using lake sediment cores

    Myrbo, A.; Howes, T.; Thompson, R.; Drake, C.; Woods, P.; Schuldt, N.; Borkholder, B.; Marty, J.; Lafrancois, T.; Pellerin, H.

    2012-12-01

    . The two-week "mini-REU" was designed to attract students with little or no independent research experience, who might be intimidated by applying for a ten-week internship away from home (but who might apply for one after completing a good mini-REU). The arc of research, from site selection to field work and lab work to data interpretation and poster presentation, must be encompassed in these brief projects, so group projects with clear goals are best suited for mini-REUs. The May 2012 project, with twelve students in four research proxy groups (charcoal, phytoliths, plant macrofossils, and zooplankton), demonstrated that a FDL lake, Rice Portage, had extensive wild rice habitat prior to early 20th-century Euroamerican ditching; this proof was required in order for FDL to gain a permit from the Army Corps of Engineers to raise the lake level as part of a wild rice restoration effort. Each proxy group had one research advisor (a graduate student or soft money researcher), plus one UMN über-advisor for the project as a whole, as well as the Fond du Lac resource manager. All of these advisors also work with the 10-week interns throughout the summer.

  8. Experimental infection with the Paderborn isolate of classical swine fever virus in 10-week-old pigs: determination of viral replication kinetics by quantitative RT-PCR, virus isolation and antigen ELISA

    Uttenthal, Åse; Storgaard, Torben; Oleksiewicz, M.B.;

    2003-01-01

    We performed experimental infection in 10-week-old pigs with the Paderborn isolate of classical swine fever virus (CSFV). Despite being epidemiologically linked to the major CSFV outbreak in The Netherlands in 1997, the in vivo replication kinetics of this isolate have to our knowledge not been...

  9. The Impact of 10 weeks of Aerobic Exercise and Supplementation of Green Tea on Lipid Profile, Insulin Resistance and Liver Enzymes (GGT, ALT, AST) in Obese Diabetic Women (type 2)

    M Izadi Ghahfarokhi; M Mogharnasi; M Faramarzi

    2015-01-01

    Background & aim: Physical training accompanied with herbal supplement consumption is one of the proposed methods for controlling obesity and its complications, such as diabetes, insulin resistance and inflammation of the liver. The purpose of this study was to evaluate the effect of 10 weeks of aerobic exercise and supplementation of green tea on lipid profile, insulin resistance and liver enzymes (GGT, ALT, AST) in obese diabetic women (type 2). Materials and Methods: A total of 46 di...

  10. The effects of a 10-week combined maximal and explosive strength and high-intesity endurance training period on neuromuscular performance and 3K time-trial in males and females

    Forssell, Jaakko

    2015-01-01

    Combined strength and endurance training has been noted to produce significant improvements in strength and endurance performances in both men and women. However, there seems to be moderate inhibitory effect regarding strength adaptations, especially considering power production. This study was conducted to investigate the effects of a 10-week combined maximal and explosive strength and high-intensity endurance training period on neuromuscular performance and 3K time-trial in m...

  11. An Investigation of Measuring Apparatus for Vo_2 During Exercise,and Effects of 10-week Exercise Training on Aerobic Work Capacity,Body Composition and Oxidative Enzymes in Skeletal Muscle in Obese-Diabetic Model OLETF Rats

    Suzuki, Masato; Seino, Tetsuya; Kimura, Masaki; Hodumi, Noriko; Terada, Shin; Higuchi, Mitsuru; Shibasaki, Toshiaki

    2005-01-01

    SUZUKI, M., SEINO, T., KIMURA, M., HODUMI, N., TERADA, S., HIGUCHI, M., and SHIBASAKI, T. An Investigation of Measuring Appatratus for VO2 During Exercise, and Effects of 10-week Exercise Training on Aerobic Work Capacity, Body Composition and Oxidative Enzymes in Skeletal Muscle in Obese-Diabetic Model OLETF Rats. Abv. Exerc. Sports Physiol., Vol.11, No.1 pp.21-31, 2005. This study was conducted to develop an open-cicuit metabolic apparatus equipped with a treadmill for obese-diabetic model ...

  12. Randomization tests

    Edgington, Eugene

    2007-01-01

    Statistical Tests That Do Not Require Random Sampling Randomization Tests Numerical Examples Randomization Tests and Nonrandom Samples The Prevalence of Nonrandom Samples in Experiments The Irrelevance of Random Samples for the Typical Experiment Generalizing from Nonrandom Samples Intelligibility Respect for the Validity of Randomization Tests Versatility Practicality Precursors of Randomization Tests Other Applications of Permutation Tests Questions and Exercises Notes References Randomized Experiments Unique Benefits of Experiments Experimentation without Mani

  13. Random Walks on Random Graphs

    Cooper, Colin; Frieze, Alan

    The aim of this article is to discuss some of the notions and applications of random walks on finite graphs, especially as they apply to random graphs. In this section we give some basic definitions, in Section 2 we review applications of random walks in computer science, and in Section 3 we focus on walks in random graphs.

  14. Random duality

    GUO TieXin; CHEN XinXiang

    2009-01-01

    The purpose of this paper is to provide a random duality theory for the further development of the theory of random conjugate spaces for random normed modules.First,the complicated stratification structure of a module over the algebra L(μ,K) frequently makes our investigations into random duality theory considerably different from the corresponding ones into classical duality theory,thus in this paper we have to first begin in overcoming several substantial obstacles to the study of stratification structure on random locally convex modules.Then,we give the representation theorem of weakly continuous canonical module homomorphisms,the theorem of existence of random Mackey structure,and the random bipolar theorem with respect to a regular random duality pair together with some important random compatible invariants.

  15. Random duality

    2009-01-01

    The purpose of this paper is to provide a random duality theory for the further development of the theory of random conjugate spaces for random normed modules. First, the complicated stratification structure of a module over the algebra L(μ, K) frequently makes our investigations into random duality theory considerably difierent from the corresponding ones into classical duality theory, thus in this paper we have to first begin in overcoming several substantial obstacles to the study of stratification structure on random locally convex modules. Then, we give the representation theorem of weakly continuous canonical module homomorphisms, the theorem of existence of random Mackey structure, and the random bipolar theorem with respect to a regular random duality pair together with some important random compatible invariants.

  16. 10周有氧训练对心力衰竭大鼠心脏重塑和运动耐力的影响%Effects of 10 -week aerobic exercise on cadiac remodeling and exercise tolerance of heart failure rats

    程蕾; 李晓霞

    2015-01-01

    was established through ligating coronary artery in clean grade Wistar rats of 8 weeks.After 4 weeks,laboratory animals were randomly divided into sham operation con-trol group (Sham),sham operation plus exercise group (Sham +E),heart failure control group (HF)and heart failure plus exercise group (HF +E).Rats in Sham +E group and HF +E group performed aerobic treadmill exercise of 10 weeks while those of Sham group and HF group main-tained resting state.Before and after the experiment,cardiac structure parameters including left ven-tricular internal diameter at diastole (LVIDd ), left ventricular internal diameter at systole (LVIDs),left ventricular anterior wall diameter at diastole (LVAWDd),left ventricular anterior wall diameter at systole (LVAWDs),left ventricular posterior wall diameter at diastole (LVPWDd) and left ventricular posterior wall diameter at systole (LVPWDs),cardiac function parameters inclu-ding fractional shortening (FS),left ventricular ejection fraction (LVEF)and heart rate (HR) were detected by ultrechocardiograph;exercise tolerance parameters including exhaust time,exhaust distance and maximal speed were tested by incremental treadmill test.After test,heart tissue was collected for weighting body weight (BW),left ventricular weight (LVW),right ventricular weight (RVW)and left ventricular mass index (LVMI),histopathology study and collagen volume fraction (CVF)by Masson staining.Results:1 )Compared with Sham group,exhaust time,exhaust dis-tance,maximal speed,BW,LVIDd,FS and LVEF reduced (P <0.01 )while LVW,LVMI, LVAWDd,LVAWDs,LVPWDd,LVPWDs and CVF raised (P <0.01)in HF group;2)Compared with HF group,exhaust time,exhaust distance,maximal speed,LVW,LVMI,LVIDd,FS and LVEF increased (P <0.01)while HR and CVF decreased (P <0.01)in HF +E group.Conclu-sion:1)HF resulted in cardiac structure and function remodeling and reduced exercise capacity;2) Aerobic treadmill training of 10 weeks reversed cardiac remodeling of heart failure rats,thus enhan

  17. Energy randomness

    Miller, Joseph S.; Rute, Jason

    2015-01-01

    Energy randomness is a notion of partial randomness introduced by Diamondstone and Kjos-Hanssen to characterize the sequences that can be elements of a Martin-L\\"of random closed set (in the sense of Barmpalias, Brodhead, Cenzer, Dashti, and Weber). It has also been applied by Allen, Bienvenu, and Slaman to the characterization of the possible zero times of a Martin-L\\"of random Brownian motion. In this paper, we show that $X \\in 2^\\omega$ is $s$-energy random if and only if $\\sum_{n\\in\\omega...

  18. Randomized random walk on a random walk

    This paper discusses generalizations of the model introduced by Kehr and Kunter of the random walk of a particle on a one-dimensional chain which in turn has been constructed by a random walk procedure. The superimposed random walk is randomised in time according to the occurrences of a stochastic point process. The probability of finding the particle in a particular position at a certain instant is obtained explicitly in the transform domain. It is found that the asymptotic behaviour for large time of the mean-square displacement of the particle depends critically on the assumed structure of the basic random walk, giving a diffusion-like term for an asymmetric walk or a square root law if the walk is symmetric. Many results are obtained in closed form for the Poisson process case, and these agree with those given previously by Kehr and Kunter. (author)

  19. 10周游泳运动对高血压大鼠血浆一氧化氮、血管性血友病因子、P-选择素含量的影响%Effects of 10-week swimming exercise on plasma nitric oxide, von Willebrand factor and P-selectin production in spontaneous hypertension rats

    陈华卫; 窦丽; 张钧

    2012-01-01

    Objective: To investigate the effects of exercise on endothelium function and platelet activity in spontaneous hypertension rats (SHR). Method: Seventeen male SHR were divided into 2 groups randomly, control group (8 SHR) and exercise group (9 SHR). In exercise group SHR performed swimming exercise (5 times/week) at moderate intensity (60min/time) for 10 weeks. Resting blood pressure was measured fortnightly during exercise training period. After the exercise period, plasma nitric oxide (NO), platelet-derived NO level and plasma von Willebrand factor (vWF), P-selectin production were defected. Result: Compared with control group, SHR resting blood pressure decreased significantly, plasma NO level and platelet NO level increased significantly, while plasma vWF and P-selectin production decreased in exercise group-Conclusion: This study implies that long-term regular aerobic exercise can inhibit resting blood pressure gently and continuously in SHR, and can improve endothelium function and platelet activity significantly in hypertension, which can control the occurrence of thrombosis complicated in hypertension.%目的:研究运动对自发性高血压大鼠内皮功能、血小板活化状态的影响.方法:10周龄,雄性自发性高血压大鼠(SHR) 17只,随机分为对照组(8只)和运动组(9只).运动组SHR进行为期10周,每周5次,每次60min的游泳运动训练.实验期间每两周测定SHR血压,10周运动后,测定血浆一氧化氮(NO)水平,血小板NO水平,血管性血友病因子(vWF)、P-选择素浓度的变化.结果:运动组大鼠血压较对照组显著下降,血浆和血小板NO水平显著上升,血浆vWF和p-选择素显著降低.结论:规则有氧运动能产生较平稳持续的降压效果,能明显改善高血压内皮功能和血小板活化状态,降低高血压血栓并发症的发生.

  20. Promoting First Relationships: Randomized Trial of a Relationship-Based Intervention for Toddlers in Child Welfare

    Spieker, Susan J.; Oxford, Monica L.; Kelly, Jean F.; Nelson, Elizabeth M.; Fleming, Charles B.

    2012-01-01

    We conducted a community based, randomized control trial of Promoting First Relationships (PFR; Kelly, Sandoval, Zuckerman, & Buehlman, 2008) to improve parenting and toddler outcomes for toddlers in state dependency. Toddlers (10 – 24 months; N = 210) with a recent placement disruption were randomized to 10-week PFR or a comparison condition. Community agency providers were trained to use PFR in the intervention for caregivers. From baseline to post-intervention follow-up, observational rati...

  1. Permanency Outcomes for Toddlers in Child Welfare Two Years After a Randomized Trial of a Parenting Intervention

    Spieker, Susan J.; Oxford, Monica L.; Fleming, Charles B.

    2014-01-01

    This study reports on child welfare outcomes of a community based, randomized control trial of Promoting First Relationships® (PFR; Kelly, Sandoval, Zuckerman, & Buehlman, 2008), a 10-week relationship-based home visiting program, on stability of children’s placements and permanency status two years after enrollment into the study. Toddlers 10 – 24 months (N = 210) with a recent placement disruption were randomized, along with their birth or foster/kin parents, to PFR (n = 105) or a compariso...

  2. Random magnetism

    The 'ingredients' which control a phase transition in well defined systems as well as in random ones (e.q. random magnetic systems) are listed and discussed within a somehow unifying perspective. Among these 'ingredients' the couplings and elements responsible for the cooperative phenomenon, the topological connectivity as well as possible topological incompatibilities, the influence of new degrees of freedom, the order parameter dimensionality, the ground state degeneracy and finally the 'quanticity' of the system are found. The general trends, though illustrated in magnetic systems, essentially hold for all phase transitions, and give a basis for connection of this area with Field theory, Theory of dynamical systems, etc. (Author)

  3. Random matrices

    Eynard, Bertrand; Ribault, Sylvain

    2015-01-01

    We provide a self-contained introduction to random matrices. While some applications are mentioned, our main emphasis is on three different approaches to random matrix models: the Coulomb gas method and its interpretation in terms of algebraic geometry, loop equations and their solution using topological recursion, orthogonal polynomials and their relation with integrable systems. Each approach provides its own definition of the spectral curve, a geometric object which encodes all the properties of a model. We also introduce the two peripheral subjects of counting polygonal surfaces, and computing angular integrals.

  4. Random Decrement

    Asmussen, J.C.; Ibrahim, S.R.; Brincker, Rune

    Abstraet Thispaper demansirates how to use the Random Decrement (RD) technique for identification o flinear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing a...

  5. Random Decrement

    Asmussen, J. C.; Ibrahim, S. R.; Brincker, Rune

    This paper demonstrates how to use the Random Decrement (RD) technique for identification of linear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing a new...

  6. Random Decrement

    Asmussen, J. C.; Ibrahim, R.; Brincker, Rune

    1998-01-01

    This paper demonstrates how to use the Random Decrement (RD) technique for identification of linear structures subjected to ambient excitation. The theory behind the technique will be presented and guidelines how to choose the different variables will be given. This is done by introducing a new...

  7. Random dynamics

    The goal of random dynamics is the derivation of the laws of Nature as we know them (standard model) from inessential assumptions. The inessential assumptions made here are expressed as sets of general models at extremely high energies: gauge glass and spacetime foam. Both sets of models lead tentatively to the standard model. (orig.)

  8. Random Vibrations

    Messaro. Semma; Harrison, Phillip

    2010-01-01

    Ares I Zonal Random vibration environments due to acoustic impingement and combustion processes are develop for liftoff, ascent and reentry. Random Vibration test criteria for Ares I Upper Stage pyrotechnic components are developed by enveloping the applicable zonal environments where each component is located. Random vibration tests will be conducted to assure that these components will survive and function appropriately after exposure to the expected vibration environments. Methodology: Random Vibration test criteria for Ares I Upper Stage pyrotechnic components were desired that would envelope all the applicable environments where each component was located. Applicable Ares I Vehicle drawings and design information needed to be assessed to determine the location(s) for each component on the Ares I Upper Stage. Design and test criteria needed to be developed by plotting and enveloping the applicable environments using Microsoft Excel Spreadsheet Software and documenting them in a report Using Microsoft Word Processing Software. Conclusion: Random vibration liftoff, ascent, and green run design & test criteria for the Upper Stage Pyrotechnic Components were developed by using Microsoft Excel to envelope zonal environments applicable to each component. Results were transferred from Excel into a report using Microsoft Word. After the report is reviewed and edited by my mentor it will be submitted for publication as an attachment to a memorandum. Pyrotechnic component designers will extract criteria from my report for incorporation into the design and test specifications for components. Eventually the hardware will be tested to the environments I developed to assure that the components will survive and function appropriately after exposure to the expected vibration environments.

  9. Behavioral Outcome Effects of Serious Gaming as an Adjunct to Treatment for Children With Attention-Deficit/Hyperactivity Disorder: A Randomized Controlled Trial

    2016-01-01

    Background The need for accessible and motivating treatment approaches within mental health has led to the development of an Internet-based serious game intervention (called “Plan-It Commander”) as an adjunct to treatment as usual for children with attention-deficit/hyperactivity disorder (ADHD). Objective The aim was to determine the effects of Plan-It Commander on daily life skills of children with ADHD in a multisite randomized controlled crossover open-label trial. Methods Participants (N=170) in this 20-week trial had a diagnosis of ADHD and ranged in age from 8 to 12 years (male: 80.6%, 137/170; female: 19.4%, 33/170). They were randomized to a serious game intervention group (group 1; n=88) or a treatment-as-usual crossover group (group 2; n=82). Participants randomized to group 1 received a serious game intervention in addition to treatment as usual for the first 10 weeks and then received treatment as usual for the next 10 weeks. Participants randomized to group 2 received treatment as usual for the first 10 weeks and crossed over to the serious game intervention in addition to treatment as usual for the subsequent 10 weeks. Primary (parent report) and secondary (parent, teacher, and child self-report) outcome measures were administered at baseline, 10 weeks, and 10-week follow-up. Results After 10 weeks, participants in group 1 compared to group 2 achieved significantly greater improvements on the primary outcome of time management skills (parent-reported; P=.004) and on secondary outcomes of the social skill of responsibility (parent-reported; P=.04), and working memory (parent-reported; P=.02). Parents and teachers reported that total social skills improved over time within groups, whereas effects on total social skills and teacher-reported planning/organizing skills were nonsignificant between groups. Within group 1, positive effects were maintained or further improved in the last 10 weeks of the study. Participants in group 2, who played the

  10. Effects of a physical education intervention on cognitive function in young children: randomized controlled pilot study

    Watson Christine; Tomporowski Phillip; Paton James Y; Boyle James ME; Fisher Abigail; McColl John H; Reilly John J

    2011-01-01

    Abstract Background Randomized controlled trials (RCT) are required to test relationships between physical activity and cognition in children, but these must be informed by exploratory studies. This study aimed to inform future RCT by: conducting practical utility and reliability studies to identify appropriate cognitive outcome measures; piloting an RCT of a 10 week physical education (PE) intervention which involved 2 hours per week of aerobically intense PE compared to 2 hours of standard ...

  11. Health promotion in individuals with mental disorders: a cluster preference randomized controlled trial

    Verhaeghe, Nick; Clays, Els; Vereecken, Carine; De Maeseneer, Jan; Maes, Lea; van Heeringen, Cornelis; De Bacquer, Dirk; Annemans, Lieven

    2013-01-01

    Background: The existing literature on weight management interventions targeting physical activity and healthy eating in mental health care appears to provide only limited evidence. The aim of the study was to examine the effectiveness of a 10-week health promotion intervention, followed by a 6-month follow-up period in individuals with mental disorders living in sheltered housing in the Flanders region (Belgium). Methods: The study had a cluster preference randomized controlled design. Tw...

  12. Quetiapine Augments the Effect of Citalopram in Non-Refractory Obsessive-Compulsive Disorder: A Randomized, Double-Blind, Placebo-Controlled Study of 76 Patients

    N.C.C. Vulink; D. Denys; S.B.A.H.A. Fluitman; J.C.M. Meinardi; H.G.M. Westenberg

    2009-01-01

    Objective: To assess the efficacy of quetiapine addition to citalopram in treatment-naive or medication-free obsessive-compulsive disorder (OCD) patients. Method. Seventy-six patients who met DSM-IV criteria for OCD and who were drug-free or drug-naive at entry were randomly assigned in a 10-week, d

  13. Paroxetine Treatment in Children and Adolescents with Obsessive-Compulsive Disorder: A Randomized, Multicenter, Double-Blind, Placebo-Controlled Trial

    Geller, Daniel A.; Wagner, Karen Dineen; Emslie, Graham; Murphy, Tanya; Carpenter, David J.; Wetherhold, Erica; Perera, Phil; Machin, Andrea; Gardiner, Christel

    2004-01-01

    Objective: To assess the efficacy and safety of paroxetine for the treatment of pediatric obsessive-compulsive disorder.Method: Children (7-11 years of age) and adolescents (12-17 years of age) meeting DSM-IV criteria for obsessive-compulsive disorder were randomized to paroxetine (10-50 mg/day) or placebo for 10 weeks. The primary efficacy…

  14. RANDOM LASSO.

    Wang, Sijian; Nan, Bin; Rosset, Saharon; Zhu, Ji

    2011-03-01

    We propose a computationally intensive method, the random lasso method, for variable selection in linear models. The method consists of two major steps. In step 1, the lasso method is applied to many bootstrap samples, each using a set of randomly selected covariates. A measure of importance is yielded from this step for each covariate. In step 2, a similar procedure to the first step is implemented with the exception that for each bootstrap sample, a subset of covariates is randomly selected with unequal selection probabilities determined by the covariates' importance. Adaptive lasso may be used in the second step with weights determined by the importance measures. The final set of covariates and their coefficients are determined by averaging bootstrap results obtained from step 2. The proposed method alleviates some of the limitations of lasso, elastic-net and related methods noted especially in the context of microarray data analysis: it tends to remove highly correlated variables altogether or select them all, and maintains maximal flexibility in estimating their coefficients, particularly with different signs; the number of selected variables is no longer limited by the sample size; and the resulting prediction accuracy is competitive or superior compared to the alternatives. We illustrate the proposed method by extensive simulation studies. The proposed method is also applied to a Glioblastoma microarray data analysis. PMID:22997542

  15. Topics in random walks in random environment

    Over the last twenty-five years random motions in random media have been intensively investigated and some new general methods and paradigms have by now emerged. Random walks in random environment constitute one of the canonical models of the field. However in dimension bigger than one they are still poorly understood and many of the basic issues remain to this day unresolved. The present series of lectures attempt to give an account of the progresses which have been made over the last few years, especially in the study of multi-dimensional random walks in random environment with ballistic behavior. (author)

  16. Completely random signed measures

    Hellmund, Gunnar

    Completely random signed measures are defined, characterized and related to Lévy random measures and Lévy bases.......Completely random signed measures are defined, characterized and related to Lévy random measures and Lévy bases....

  17. Randomized LU Decomposition

    Shabat, Gil; Shmueli, Yaniv; Aizenbud, Yariv; Averbuch, Amir

    2013-01-01

    We present a fast randomized algorithm that computes a low rank LU decomposition. Our algorithm uses random projections type techniques to efficiently compute a low rank approximation of large matrices. The randomized LU algorithm can be parallelized and further accelerated by using sparse random matrices in its projection step. Several different error bounds are proven for the algorithm approximations. To prove these bounds, recent results from random matrix theory related to subgaussian mat...

  18. Psychological and cognitive outcomes of a randomized trial of exercise among patients with chronic obstructive pulmonary disease.

    Emery, C F; Schein, R L; Hauck, E R; MacIntyre, N R

    1998-05-01

    Exercise rehabilitation is recommended increasingly for patients with chronic obstructive pulmonary disease (COPD). This study examined the effect of exercise and education on 79 older adults (M age = 66.6 +/- 6.5 years; 53% female) with COPD, randomly assigned to 10 weeks of (a) exercise, education, and stress management (EXESM; n = 29); (b) education and stress management (ESM; n = 25); or (c) waiting list (WL; n = 25). EXESM included 37 sessions of exercise, 16 educational lectures, and 10 weekly stress management classes. ESM included only the 16 lectures and 10 stress management classes. Before and after the intervention, assessments were conducted of physiological functioning (pulmonary function, exercise endurance), psychological well-being (depression, anxiety, quality of life), and cognitive functioning (attention, motor speed, mental efficiency, verbal processing). Repeated measures multivariate analysis of variance indicated that EXESM participants experienced changes not observed among ESM and WL participants, including improved endurance, reduced anxiety, and improved cognitive performance (verbal fluency). PMID:9619472

  19. Comparing MTI randomization procedures to blocked randomization.

    Berger, Vance W; Bejleri, Klejda; Agnor, Rebecca

    2016-02-28

    Randomization is one of the cornerstones of the randomized clinical trial, and there is no shortage of methods one can use to randomize patients to treatment groups. When deciding which one to use, researchers must bear in mind that not all randomization procedures are equally adept at achieving the objective of randomization, namely, balanced treatment groups. One threat is chronological bias, and permuted blocks randomization does such a good job at controlling chronological bias that it has become the standard randomization procedure in clinical trials. But permuted blocks randomization is especially vulnerable to selection bias, so as a result, the maximum tolerated imbalance (MTI) procedures were proposed as better alternatives. In comparing the procedures, we have somewhat of a false controversy, in that actual practice goes uniformly one way (permuted blocks), whereas scientific arguments go uniformly the other way (MTI procedures). There is no argument in the literature to suggest that the permuted block design is better than or even as good as the MTI procedures, but this dearth is matched by an equivalent one regarding actual trials using the MTI procedures. So the 'controversy', if we are to call it that, pits misguided precedent against sound advice that tends to be ignored in practice. We shall review the issues to determine scientifically which of the procedures is better and, therefore, should be used. PMID:26337607

  20. Design and methods of a social network isolation study for reducing respiratory infection transmission: The eX-FLU cluster randomized trial

    Aiello, Allison E.; Simanek, Amanda M.; Marisa C Eisenberg; Alison R. Walsh; Brian Davis; Erik Volz; Caroline Cheng; Rainey, Jeanette J.; Amra Uzicanin; Hongjiang Gao; Nathaniel Osgood; Dylan Knowles; Kevin Stanley; Kara Tarter; Monto, Arnold S.

    2016-01-01

    Background: Social networks are increasingly recognized as important points of intervention, yet relatively few intervention studies of respiratory infection transmission have utilized a network design. Here we describe the design, methods, and social network structure of a randomized intervention for isolating respiratory infection cases in a university setting over a 10-week period. Methodology/principal findings: 590 students in six residence halls enrolled in the eX-FLU study during a ...

  1. Random walks on combs

    Durhuus, B; Wheater, J; Durhuus, Bergfinnur; Jonsson, Thordur; Wheater, John

    2006-01-01

    We develop techniques to obtain rigorous bounds on the behaviour of random walks on combs. Using these bounds we calculate exactly the spectral dimension of random combs with infinite teeth at random positions or teeth with random but finite length. We also calculate exactly the spectral dimension of some fixed non-translationally invariant combs. We relate the spectral dimension to the critical exponent of the mass of the two-point function for random walks on random combs, and compute mean displacements as a function of walk duration. We prove that the mean first passage time is generally infinite for combs with anomalous spectral dimension.

  2. Matricially free random variables

    Lenczewski, Romuald

    2008-01-01

    We show that the operatorial framework developed by Voiculescu for free random variables can be extended to arrays of random variables whose multiplication imitates matricial multiplication. The associated notion of independence, called matricial freeness, can be viewed as a generalization of both freeness and monotone independence. At the same time, the sums of matricially free random variables, called random pseudomatrices, are closely related to Gaussian random matrices. The main results presented in this paper concern the standard and tracial central limit theorems for random pseudomatrices and the corresponding limit distributions which can be viewed as matricial generalizations of semicirle laws.

  3. On Gaussian random supergravity

    We study the distribution of metastable vacua and the likelihood of slow roll inflation in high dimensional random landscapes. We consider two examples of landscapes: a Gaussian random potential and an effective supergravity potential defined via a Gaussian random superpotential and a trivial Kähler potential. To examine these landscapes we introduce a random matrix model that describes the correlations between various derivatives and we propose an efficient algorithm that allows for a numerical study of high dimensional random fields. Using these novel tools, we find that the vast majority of metastable critical points in N dimensional random supergravities are either approximately supersymmetric with |F|≪Msusy or supersymmetric. Such approximately supersymmetric points are dynamical attractors in the landscape and the probability that a randomly chosen critical point is metastable scales as log (P)∝−N. We argue that random supergravities lead to potentially interesting inflationary dynamics

  4. Quantum Random Number Generators

    Herrero-Collantes, Miguel; Garcia-Escartin, Juan Carlos

    2016-01-01

    Random numbers are a fundamental resource in science and engineering with important applications in simulation and cryptography. The inherent randomness at the core of quantum mechanics makes quantum systems a perfect source of entropy. Quantum random number generation is one of the most mature quantum technologies with many alternative generation methods. We discuss the different technologies in quantum random number generation from the early devices based on radioactive decay to the multipl...

  5. Blocked Randomization with Randomly Selected Block Sizes

    Jimmy Efird

    2010-12-01

    Full Text Available When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  6. Blocked randomization with randomly selected block sizes.

    Efird, Jimmy

    2011-01-01

    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes. PMID:21318011

  7. Random walks, random fields, and disordered systems

    Černý, Jiří; Kotecký, Roman

    2015-01-01

    Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

  8. Misuse of randomization

    Liu, Jianping; Kjaergard, Lise Lotte; Gluud, Christian

    2002-01-01

    The quality of randomization of Chinese randomized trials on herbal medicines for hepatitis B was assessed. Search strategy and inclusion criteria were based on the published protocol. One hundred and seventy-six randomized clinical trials (RCTs) involving 20,452 patients with chronic hepatitis B...... virus (HBV) infection were identified that tested Chinese medicinal herbs. They were published in 49 Chinese journals. Only 10% (18/176) of the studies reported the method by which they randomized patients. Only two reported allocation concealment and were considered as adequate. Twenty percent (30....../150) of the studies were imbalanced at the 0.05 level of probability for the two treatments and 13.3% (20/150) imbalanced at the 0.01 level in the randomization. It is suggested that there may exist misunderstanding of the concept and the misuse of randomization based on the review....

  9. The Randomized Dependence Coefficient

    Lopez-Paz, David; Hennig, Philipp; Schölkopf, Bernhard

    2013-01-01

    We introduce the Randomized Dependence Coefficient (RDC), a measure of non-linear dependence between random variables of arbitrary dimension based on the Hirschfeld-Gebelein-R\\'enyi Maximum Correlation Coefficient. RDC is defined in terms of correlation of random non-linear copula projections; it is invariant with respect to marginal distribution transformations, has low computational cost and is easy to implement: just five lines of R code, included at the end of the paper.

  10. Random mapping statistics

    Flajolet, Philippe; Odlyzko, Andrew M.

    1989-01-01

    Random mappings from a finite set into itself are either a heuristic or an exact model for a variety of applications in random number generation, computational number theory, cryptography, and the analysis of algorithms at large. This paper introduces a general framework in which the analysis of about twenty characteristic parameters of random mappings is carried out. These parameters are studied systematically through the use of generating functions and singularity analysis. In particular, a...

  11. Randomization and Dynamic Consistency

    Jürgen Eichberger; Simon Grant; David Kelsey

    2014-01-01

    Raiffa (1961) has suggested that ambiguity aversion will cause a strict preference for randomization. We show that dynamic consistency implies that individuals will be indifferent to ex ante randomizations. On the other hand, it is possible for a dynamically-consistent ambiguity averse preference relation to exhibit a strict preference for some ex post randomizations. We argue that our analysis throws some light on the recent debate about paradoxes for the smooth model of ambiguity. We show t...

  12. Random Sampling with Removal

    Gärtner, Bernd; Lengler, Johannes; Szedlak, May

    2015-01-01

    Random sampling is a classical tool in constrained optimization. Under favorable conditions, the optimal solution subject to a small subset of randomly chosen constraints violates only a small subset of the remaining constraints. Here we study the following variant that we call random sampling with removal: suppose that after sampling the subset, we remove a fixed number of constraints from the sample, according to an arbitrary rule. Is it still true that the optimal solution of the reduced s...

  13. Random Maxout Features

    Mroueh, Youssef; Rennie, Steven; Goel, Vaibhava

    2015-01-01

    In this paper, we propose and study random maxout features, which are constructed by first projecting the input data onto sets of randomly generated vectors with Gaussian elements, and then outputing the maximum projection value for each set. We show that the resulting random feature map, when used in conjunction with linear models, allows for the locally linear estimation of the function of interest in classification tasks, and for the locally linear embedding of points when used for dimensi...

  14. Random fractal dendrites

    Croydon, David (David Alexander); Hambly, Ben M.; Dr. Ben Hambly

    2006-01-01

    Dendrites are tree-like topological spaces, and in this thesis, the physical characteristics of various random fractal versions of this type of set are investigated. This work will contribute to the development of analysis on fractals, an area which has grown considerably over the last twenty years. First, a collection of random self-similar dendrites is constructed, and their Hausdorff dimension is calculated. Previous results determining this quantity for random self-simi...

  15. On Random Rough Sets

    Weizhi Wu

    2006-01-01

    In this paper,the concept of a random rough set which includes the mechanisms of numeric and non-numeric aspects of uncertain knowledge is introduced. It is proved that for any belief structure and its inducing belief and plausibility measures there exists a random approximation space such that the associated lower and upper probabilities are respectively the given belief and plausibility measures, and vice versa. And for a random approximation space generated from a totally random set, its inducing lower and upper probabilities are respectively a pair of necessity and possibility measures.

  16. Acupoint Stimulation on Weight Reduction for Obesity: A Randomized Sham-Controlled Study.

    Yeh, Mei-Ling; Chu, Nain-Feng; Hsu, Man-Ying F; Hsu, Chin-Che; Chung, Yu-Chu

    2015-12-01

    Auricular acupoint stimulation has become a popular weight loss method. However, its efficacy for obesity treatment has not been fully studied. This study aimed to investigate the effect of a 10-week intervention of auricular electrical stimulation combined with auricular acupressure on weight reduction in obese outpatients. In this single-blind randomized sham-controlled study, 134 participants were randomly assigned to an experimental group receiving stimulation at true acupoints, or a sham group receiving stimulation delivered in the same manner but at sham acupoints. Each participant received nutrition counseling by a nutritionist weekly. The results showed significant differences in body mass index, blood pressure, total cholesterol, triglyceride, and leptin or adiponectin over time within the group, but not between the groups. This study could not exclude the effect of placebo and dietary consultation. Further study that adds a control group receiving no treatment is therefore needed to confirm the effects of auricular acupressure. PMID:25183702

  17. Clinical and histological effect of a low glycaemic load diet in treatment of acne vulgaris in Korean patients: a randomized, controlled trial.

    Kwon, Hyuck Hoon; Yoon, Ji Young; Hong, Jong Soo; Jung, Jae Yoon; Park, Mi Sun; Suh, Dae Hun

    2012-05-01

    Recent studies have suggested that dietary factors, specifically glycaemic load, may be involved in the pathogenesis of acne. The aim of this study was to determine the clinical and histological effects on acne lesions of a low glycaemic load diet. A total of 32 patients with mild to moderate acne were randomly assigned to either a low glycaemic load diet or a control group diet, and completed a 10-week, parallel dietary intervention trial. Results indicate successful lowering of the glycaemic load. Subjects within the low glycaemic group demonstrated significant clinical improvement in the number of both non-inflammatory and inflammatory acne lesions. Histopathological examination of skin samples revealed several characteristics, including reduced size of sebaceous glands, decreased inflammation, and reduced expression of sterol regulatory element-binding protein-1, and interleukin-8 in the low glycaemic load group. A reduction in glycaemic load of the diet for 10 weeks resulted in improvements in acne. PMID:22678562

  18. Random and vector measures

    Rao, M M

    2011-01-01

    The book is devoted to the structural analysis of vector and random (or both) valued countably additive measures, and used for integral representations of random fields. The spaces can be Banach or Frechet types. Several stationary aspects and related processes are analyzed whilst numerous new results are included and many research avenues are opened up.

  19. Random surfaces and strings

    The theory of strings is the theory of random surfaces. I review the present attempts to regularize the world sheet of the string by triangulation. The corresponding statistical theory of triangulated random surfaces has a surprising rich structure, but the connection to conventional string theory seems non-trivial. (orig.)

  20. On fairness and randomness

    Jaeger, Manfred

    2009-01-01

    probabilistic behavior. On the basis of stopping strategies it is then shown that fair behavior corresponds in a precise sense to random behavior in the sense of Martin-Löf's definition of randomness. We view probabilistic systems as concrete implementations of more abstract non-deterministic systems. Under...

  1. Hashing, Randomness and Dictionaries

    Pagh, Rasmus

    time and memory space. To some extent we also consider lower bounds, i.e., we attempt to show limitations on how efficient algorithms are possible. A central theme in the thesis is randomness. Randomized algorithms play an important role, in particular through the key technique of hashing. Additionally...

  2. Randomness: quantum versus classical

    Khrennikov, Andrei

    2015-01-01

    Recent tremendous development of quantum information theory led to a number of quantum technological projects, e.g., quantum random generators. This development stimulates a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is elaboration of a consistent and commonly accepted interpretation of quantum state. Closely related problem is clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. The second part of this review is devoted to the information interpretation of quantum mechanics (QM) in the spirit of Zeilinger and Brukner (and QBism of Fuchs et al.) and physics in general (e.g., Wheeler's "it from bit") as well as digital philosophy of Chaitin (with historical coupling to ideas of Leibnitz). Finally, w...

  3. Quantum random number generator

    Pooser, Raphael C.

    2016-05-10

    A quantum random number generator (QRNG) and a photon generator for a QRNG are provided. The photon generator may be operated in a spontaneous mode below a lasing threshold to emit photons. Photons emitted from the photon generator may have at least one random characteristic, which may be monitored by the QRNG to generate a random number. In one embodiment, the photon generator may include a photon emitter and an amplifier coupled to the photon emitter. The amplifier may enable the photon generator to be used in the QRNG without introducing significant bias in the random number and may enable multiplexing of multiple random numbers. The amplifier may also desensitize the photon generator to fluctuations in power supplied thereto while operating in the spontaneous mode. In one embodiment, the photon emitter and amplifier may be a tapered diode amplifier.

  4. Random attractors for asymptotically upper semicompact multivalue random semiflows

    2007-01-01

    The present paper studied the dynamics of some multivalued random semiflow. The corresponding concept of random attractor for this case was introduced to study asymptotic behavior. The existence of random attractor of multivalued random semiflow was proved under the assumption of pullback asymptotically upper semicompact, and this random attractor is random compact and invariant. Furthermore, if the system has ergodicity, then this random attractor is the limit set of a deterministic bounded set.

  5. A random walk with a branching system in random environments

    Ying-qiu LI; Xu LI; Quan-sheng LIU

    2007-01-01

    We consider a branching random walk in random environments, where the particles are reproduced as a branching process with a random environment (in time), and move independently as a random walk on Z with a random environment (in locations). We obtain the asymptotic properties on the position of the rightmost particle at time n, revealing a phase transition phenomenon of the system.

  6. Random Fiber Laser

    Christiano J. S. de Matos; Menezes, Leonardo de S.; Brito-Silva, Antônio M.; Gámez, M. A. Martinez; Gomes, Anderson S. L.; de Araújo, Cid B.

    2007-01-01

    We investigate the effects of two dimensional confinement on the lasing properties of a classical random laser system operating in the incoherent feedback (diffusive) regime. A suspension of 250nm rutile (TiO2) particles in a Rhodamine 6G solution was inserted into the hollow core of a photonic crystal fiber (PCF) generating the first random fiber laser and a novel quasi-one-dimensional RL geometry. Comparison with similar systems in bulk format shows that the random fiber laser presents an e...

  7. Random Fiber Laser

    de Matos, Christiano J S; Brito-Silva, Antônio M; Gámez, M A Martinez; Gomes, Anderson S L; de Araújo, Cid B

    2007-01-01

    We investigate the effects of two dimensional confinement on the lasing properties of a classical random laser system operating in the incoherent feedback (diffusive) regime. A suspension of 250nm rutile (TiO2) particles in a Rhodamine 6G solution was inserted into the hollow core of a photonic crystal fiber (PCF) generating the first random fiber laser and a novel quasi-one-dimensional RL geometry. Comparison with similar systems in bulk format shows that the random fiber laser presents an efficiency that is at least two orders of magnitude higher.

  8. Random access photonic metamaterials

    Cencillo-Abad, P.; Ou, J.Y.; Valente, J.; Plum, E.; Zheludev, N.I.

    2015-01-01

    We demonstrate the first addressable reconfigurable photonic metamaterials thus enabling control over optical material properties with simultaneous spatial and temporal resolution. Potential applications of random access metadevices include active focusing, beam steering, dynamic transformation optics and video holography.

  9. Tunable random packings

    We present an experimental protocol that allows one to tune the packing fraction η of a random pile of ferromagnetic spheres from a value close to the lower limit of random loose packing ηRLP≅0.56 to the upper limit of random close packing ηRCP≅0.64. This broad range of packing fraction values is obtained under normal gravity in air, by adjusting a magnetic cohesion between the grains during the formation of the pile. Attractive and repulsive magnetic interactions are found to affect stongly the internal structure and the stability of sphere packing. After the formation of the pile, the induced cohesion is decreased continuously along a linear decreasing ramp. The controlled collapse of the pile is found to generate various and reproducible values of the random packing fraction η

  10. Drawing a random number

    Wanscher, Jørgen Bundgaard; Sørensen, Majken Vildrik

    2006-01-01

    Random numbers are used for a great variety of applications in almost any field of computer and economic sciences today. Examples ranges from stock market forecasting in economics, through stochastic traffic modelling in operations research to photon and ray tracing in graphics. The construction of...... a model or a solution method requires certain characteristics of the random numbers used. This is usually a distribution classification, which the sequence of random numbers must fulfill; of these some are very hard to fulfill and others are next to impossible. Today mathematics allows us to...... is to generate highly uniform multidimensional draws, which are highly relevant for todays traffic models. This paper shows among others combined shuffling and scrambling seems needless, that scrambling gives the lowest correlation and that there are detectable differences between random numbers...

  11. Spiders in random environment

    Gallesco, Christophe; Popov, Serguei; Vachkovskaia, Marina

    2010-01-01

    A spider consists of several, say $N$, particles. Particles can jump independently according to a random walk if the movement does not violate some given restriction rules. If the movement violates a rule it is not carried out. We consider random walk in random environment (RWRE) on $\\Z$ as underlying random walk. We suppose the environment $\\omega=(\\omega_x)_{x \\in \\Z}$ to be elliptic, with positive drift and nestling, so that there exists a unique positive constant $\\kappa$ such that $\\E[((1-\\omega_0)/\\omega_0)^{\\kappa}]=1$. The restriction rules are kept very general; we only assume transitivity and irreducibility of the spider. The main result is that the speed of a spider is positive if $\\kappa/N>1$ and null if $\\kappa/N<1$. In particular, if $\\kappa/N <1$ a spider has null speed but the speed of a (single) RWRE is positive.

  12. Random maintenance policies

    Nakagawa, Toshio

    2014-01-01

    Exploring random maintenance models, this book provides an introduction to the implementation of random maintenance, and it is one of the first books to be written on this subject.  It aims to help readers learn new techniques for applying random policies to actual reliability models, and it provides new theoretical analyses of various models including classical replacement, preventive maintenance and inspection policies. These policies are applied to scheduling problems, backup policies of database systems, maintenance policies of cumulative damage models, and reliability of random redundant systems. Reliability theory is a major concern for engineers and managers, and in light of Japan’s recent earthquake, the reliability of large-scale systems has increased in importance. This also highlights the need for a new notion of maintenance and reliability theory, and how this can practically be applied to systems. Providing an essential guide for engineers and managers specializing in reliability maintenance a...

  13. Randomized Aperture Imaging

    Peng, Xiaopeng; Swartzlander, Grover A

    2016-01-01

    Speckled images of a binary broad band light source (600-670 nm), generated by randomized reflections or transmissions, were used to reconstruct a binary image by use of multi-frame blind deconvolution algorithms. Craft store glitter was used as reflective elements. Another experiment used perforated foil. Also reported here are numerical models that afforded controlled tip-tilt and piston aberrations. These results suggest the potential importance of a poorly figured, randomly varying segmented imaging system.

  14. Ensembles on Random Patches

    Louppe, Gilles; Geurts, Pierre

    2012-01-01

    In this paper, we consider supervised learning under the assumption that the available memory is small compared to the dataset size. This general framework is relevant in the context of big data, distributed databases and embedded systems. We investigate a very simple, yet effective, ensemble framework that builds each individual model of the ensemble from a random patch of data obtained by drawing random subsets of both instances and features from the whole dataset. We carry out an extensive...

  15. Random copying in space

    Blythe, Richard A

    2011-01-01

    Random copying is a simple model for population dynamics in the absence of selection, and has been applied to both biological and cultural evolution. In this work, we investigate the effect that spatial structure has on the dynamics. We focus in particular on how a measure of the diversity in the population changes over time. We show that even when the vast majority of a population's history may be well-described by a spatially-unstructured model, spatial structure may nevertheless affect the expected level of diversity seen at a local scale. We demonstrate this phenomenon explicitly by examining the random copying process on small-world networks, and use our results to comment on the use of simple random-copying models in an empirical context.

  16. Reconstructing random media

    We formulate a procedure to reconstruct the structure of general random heterogeneous media from limited morphological information by extending the methodology of Rintoul and Torquato [J. Colloid Interface Sci. 186, 467 (1997)] developed for dispersions. The procedure has the advantages that it is simple to implement and generally applicable to multidimensional, multiphase, and anisotropic structures. Furthermore, an extremely useful feature is that it can incorporate any type and number of correlation functions in order to provide as much morphological information as is necessary for accurate reconstruction. We consider a variety of one- and two-dimensional reconstructions, including periodic and random arrays of rods, various distribution of disks, Debye random media, and a Fontainebleau sandstone sample. We also use our algorithm to construct heterogeneous media from specified hypothetical correlation functions, including an exponentially damped, oscillating function as well as physically unrealizable ones. copyright 1998 The American Physical Society

  17. Random errors revisited

    Jacobsen, Finn

    2000-01-01

    It is well known that the random errors of sound intensity estimates can be much larger than the theoretical minimum value determined by the BT-product, in particular under reverberant conditions and when there are several sources present. More than ten years ago it was shown that one can predict...... the random errors of estimates of the sound intensity in, say, one-third octave bands from the power and cross power spectra of the signals from an intensity probe determined with a dual channel FFT analyser. This is not very practical, though. In this paper it is demonstrated that one can predict the...... random errors from the power and cross power spectra determined with the same spectral resolution as the sound intensity itself....

  18. Coded Random Access

    Paolini, Enrico; Stefanovic, Cedomir; Liva, Gianluigi;

    2015-01-01

    The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered as...... waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access......, in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of...

  19. Graphene random laser

    Marini, Andrea

    2015-01-01

    Manipulating and controlling the optical energy flow inside random media is a research frontier of photonics and the basis of novel laser designs. In particular, light amplification in randomly dispersed active inclusions under external pumping has been extensively investigated, although it still lacks external tunability, reproducibility, and control over the beam spatial pattern, thus hindering its application in practical devices. Here we show that a graphene random metamaterial provides the means to overcome these limitations through its extraordinarily-low threshold for saturable absorption. The nonlinear properties of nano-graphene combined with an optically pumped gain medium allow us to controllably tune the system from chaotic to stable single-mode lasing. Our results hold great potential for the development of single-mode cavity-free lasers with engineered beam patterns in disordered media.

  20. RANDOM SINGULAR INTEGRAL OF RANDOM PROCESS WITH SECOND ORDER MOMENT

    Wang Chuanrong

    2005-01-01

    This paper discussses the random singular integral of random process with second order moment, establishes the concepts of the random singular integral and proves that it's a linear bounded operator of space Hα(L)(m, s). Then Plemelj formula and some other properties for random singular integral are proved.

  1. Ten weeks of physical-cognitive-mindfulness training reduces fear-avoidance beliefs about work-related activity: Randomized controlled trial.

    Jay, Kenneth; Brandt, Mikkel; Jakobsen, Markus Due; Sundstrup, Emil; Berthelsen, Kasper Gymoese; Schraefel, Mc; Sjøgaard, Gisela; Andersen, Lars L

    2016-08-01

    People with chronic musculoskeletal pain often experience pain-related fear of movement and avoidance behavior. The Fear-Avoidance model proposes a possible mechanism at least partly explaining the development and maintenance of chronic pain. People who interpret pain during movement as being potentially harmful to the organism may initiate a vicious behavioral cycle by generating pain-related fear of movement accompanied by avoidance behavior and hyper-vigilance.This study investigates whether an individually adapted multifactorial approach comprised of biopsychosocial elements, with a focus on physical exercise, mindfulness, and education on pain and behavior, can decrease work-related fear-avoidance beliefs.As part of a large scale 10-week worksite randomized controlled intervention trial focusing on company initiatives to combat work-related musculoskeletal pain and stress, we evaluated fear-avoidance behavior in 112 female laboratory technicians with chronic neck, shoulder, upper back, lower back, elbow, and hand/wrist pain using the Fear-Avoidance Beliefs Questionnaire at baseline, before group allocation, and again at the post intervention follow-up 10 weeks later.A significant group by time interaction was observed (P activity-related, fear-avoidance beliefs, as assessed by the Fear-avoidance Beliefs Questionnaire, can be significantly reduced by 10 weeks of physical-cognitive-mindfulness training in female laboratory technicians with chronic pain. PMID:27559939

  2. Random quantum operations

    Bruzda, Wojciech [Mark Kac Complex Systems Research Centre, Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland)], E-mail: wojtek@gorce.if.uj.edu.pl; Cappellini, Valerio [Mark Kac Complex Systems Research Centre, Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Sommers, Hans-Juergen [Fachbereich Physik, Universitaet Duisburg-Essen, Campus Duisburg, 47048 Duisburg (Germany); Zyczkowski, Karol [Mark Kac Complex Systems Research Centre, Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotnikow 32/44, 02-668 Warszawa (Poland)

    2009-01-12

    We define a natural ensemble of trace preserving, completely positive quantum maps and present algorithms to generate them at random. Spectral properties of the superoperator {phi} associated with a given quantum map are investigated and a quantum analogue of the Frobenius-Perron theorem is proved. We derive a general formula for the density of eigenvalues of {phi} and show the connection with the Ginibre ensemble of real non-symmetric random matrices. Numerical investigations of the spectral gap imply that a generic state of the system iterated several times by a fixed generic map converges exponentially to an invariant state.

  3. Random unistochastic matrices

    Zyczkowski, Karol [Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotnikow 32/44, 02-668 Warsaw (Poland); Kus, Marek [Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotnikow 32/44, 02-668 Warsaw (Poland); Slomczynski, Wojciech [Instytut Matematyki, Uniwersytet Jagiellonski, ul. Reymonta 4, 30-059 Cracow (Poland); Sommers, Hans-Juergen [Fachbereich 7 Physik, Universitaet Essen, 45117 Essen (Germany)

    2003-03-28

    An ensemble of random unistochastic (orthostochastic) matrices is defined by taking squared moduli of elements of random unitary (orthogonal) matrices distributed according to the Haar measure on U(N) (or O(N)). An ensemble of symmetric unistochastic matrices is obtained with use of unitary symmetric matrices pertaining to the circular orthogonal ensemble. We study the distribution of complex eigenvalues of bistochastic, unistochastic and orthostochastic matrices in the complex plane. We compute averages (entropy, traces) over the ensembles of unistochastic matrices and present inequalities concerning the entropies of products of bistochastic matrices.

  4. Lectures on random evolution

    Pinsky, Mark A

    1991-01-01

    Random evolution denotes a class of stochastic processes which evolve according to a rule which varies in time according to jumps. This is in contrast to diffusion processes, which assume that the rule changes continuously with time. Random evolutions provide a very flexible language, having the advantage that they permit direct numerical simulation-which is not possible for a diffusion process. Furthermore, they allow connections with hyperbolic partial differential equations and the kinetic theory of gases, which is impossible within the domain of diffusion proceses. They also posses great g

  5. Free Completely Random Measures

    Collet, Francesca

    2011-01-01

    Free probability is a noncommutative probability theory introduced by Voiculescu where the concept of independence of classical probability is replaced by the concept of freeness. An important connection between free and classical infinitely divisibility was established by Bercovici and Pata (1999) in form of a bijection, mapping the class of classical infinitely divisible laws into the class of free infinitely divisible laws. A particular class of infinitely divisible laws are the completely random measures introduced by Kingman (1967). In this paper, a free analogous of completely random measures is introduced and, a free Poisson process characterization is provided as well as a representation through a free cumulant transform. Furthermore, some examples are displayed.

  6. Intermittency and random matrices

    Sokoloff, Dmitry; Illarionov, E. A.

    2015-08-01

    A spectacular phenomenon of intermittency, i.e. a progressive growth of higher statistical moments of a physical field excited by an instability in a random medium, attracted the attention of Zeldovich in the last years of his life. At that time, the mathematical aspects underlying the physical description of this phenomenon were still under development and relations between various findings in the field remained obscure. Contemporary results from the theory of the product of independent random matrices (the Furstenberg theory) allowed the elaboration of the phenomenon of intermittency in a systematic way. We consider applications of the Furstenberg theory to some problems in cosmology and dynamo theory.

  7. Randomized Filtering Algorithms

    Katriel, Irit; Van Hentenryck, Pascal

    2008-01-01

    Filtering every global constraint of a CPS to are consistency at every search step can be costly and solvers often compromise on either the level of consistency or the frequency at which are consistency is enforced. In this paper we propose two randomized filtering schemes for dense instances...

  8. Random intersection graph process

    Bloznelis, Mindaugas; Karonski, Michal

    2013-01-01

    We introduce a random intersection graph process aimed at modeling sparse evolving affiliation networks that admit tunable (power law) degree distribution and assortativity and clustering coefficients. We show the asymptotic degree distribution and provide explicit asymptotic formulas for assortativity and clustering coefficients.

  9. Random Boolean Networks

    Drossel, Barbara

    2007-01-01

    This review explains in a self-contained way the properties of random Boolean networks and their attractors, with a special focus on critical networks. Using small example networks, analytical calculations, phenomenological arguments, and problems to solve, the basic concepts are introduced and important results concerning phase diagrams, numbers of relevant nodes and attractor properties are derived.

  10. Asymmetric Carrier Random PWM

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;

    2010-01-01

    This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...

  11. Testing for Subcellular Randomness

    Okunoye, Babatunde O

    2008-01-01

    Statistical tests were conducted on 1,000 numbers generated from the genome of Bacteriophage T4, obtained from GenBank with accession number AF158101.The numbers passed the non-parametric, distribution-free tests.Deoxyribonucleic acid was discovered to be a random number generator, existent in nature.

  12. Photographic dataset: random peppercorns

    Helenius, Teemu

    2016-01-01

    This is a photographic dataset collected for testing image processing algorithms. The idea is to have sets of different but statistically similar images. In this work the images show randomly distributed peppercorns. The dataset is made available at www.fips.fi/photographic_dataset.php .

  13. Generating "Random" Integers

    Griffiths, Martin

    2011-01-01

    One of the author's undergraduate students recently asked him whether it was possible to generate a random positive integer. After some thought, the author realised that there were plenty of interesting mathematical ideas inherent in her question. So much so in fact, that the author decided to organise a workshop, open both to undergraduates and…

  14. Randomized clinical trial

    Olesen, Anne Estrup; Nielsen, Lecia Møller; Larsen, Isabelle Myriam;

    2015-01-01

    : The study was a randomized, double-blinded, placebo-controlled, crossover trial in healthy males. Esophageal electrical, thermal, mechanical, and chemical stimulations were performed, pain perception was rated, and referred pain areas were drawn. Sensitization was induced by intraluminal esophageal acid...

  15. Effect of physical training on function of chronically painful muscles: A randomized controlled trial

    Andersen, Lars L; Andersen, Christoffer H; Zebis, Mette K;

    2008-01-01

    Purpose: Pain and tenderness of the upper trapezius muscle is frequent in several occupational groups. The objective of this study is to investigate the effect of three contrasting interventions on muscle function and pain in women with trapezius myalgia. Methods: A group of employed women (n=42......) with a clinical diagnosis of trapezius myalgia participated in a 10 week randomized controlled intervention; specific strength training of the neck/shoulder muscles (SST), general fitness training performed as leg-bicycling (GFT), or a reference intervention without physical activity (REF). Torque and...... during the reference contraction decreased significantly for both the trapezius and deltoid muscles (P<0.01). Conclusion: In conclusion, specific strength training relieves pain and increases maximal activity specifically of the painful trapezius muscle, leading to increased shoulder abduction strength...

  16. Acemannan hydrogel dressing versus saline dressing for pressure ulcers. A randomized, controlled trial.

    Thomas, D R; Goode, P S; LaMaster, K; Tennyson, T

    1998-10-01

    Aloe vera has been used for centuries as a topical treatment for various conditions and as a cathartic. An amorphous hydrogel dressing derived from the aloe plant (Carrasyn Gel Wound Dressing, Carrington Laboratories, Inc., Irving, TX) is approved by the Food and Drug Administration for the management of Stages I through IV pressure ulcers. To evaluate effectiveness of this treatment, 30 patients were randomized to receive either daily topical application of the hydrogel study dressing (acemannan hydrogel wound dressing) or a moist saline gauze dressing. Complete healing of the study ulcer occurred in 19 of 30 subjects (63%) during the 10-week observation period. No difference was observed in complete healing between the experimental and the control groups (odds ratio 0.93, 95% CI 0.16, 5.2). This study indicates that the acemannan hydrogel dressing is as effective as, but is not superior to, a moist saline gauze wound dressing for the management of pressure ulcers. PMID:10326343

  17. Effect of Workplace- versus Home-Based Physical Exercise on Muscle Response to Sudden Trunk Perturbation among Healthcare Workers: A Cluster Randomized Controlled Trial

    Jakobsen, Markus D.; Emil Sundstrup; Mikkel Brandt; Kenneth Jay; Per Aagaard; Andersen, Lars L.

    2015-01-01

    Objectives. The present study investigates the effect of workplace- versus home-based physical exercise on muscle reflex response to sudden trunk perturbation among healthcare workers. Methods. Two hundred female healthcare workers (age: 42 [SD 11], BMI: 24 [SD 4], and pain intensity: 3.1 [SD 2.2] on a scale of 0–10) from 18 departments at three hospitals were randomized at the cluster level to 10 weeks of (1) workplace physical exercise (WORK) performed in groups during working hours for 5 ×...

  18. Random very loose packings.

    Ciamarra, Massimo Pica; Coniglio, Antonio

    2008-09-19

    We measure the number Omega(phi) of mechanically stable states of volume fraction phi of a granular assembly under gravity. The granular entropy S(phi)=logOmega(phi) vanishes both at high density, at phi approximately equal to phi_rcp, and a low density, at phi approximately equal to phi_rvlp, where phi_rvlp is a new lower bound we call random very loose pack. phi_rlp is the volume fraction where the entropy is maximal. These findings allow for a clear explanation of compaction experiments and provide the first first-principle definition of the random loose volume fraction. In the context of the statistical mechanics approach to static granular materials, states with phi

  19. Decorating random quadrangulations

    On various regular lattices (simple cubic, body centred cubic, etc) decorating an edge with an Ising spin coupled by bonds of strength L to the original vertex spins and competing with a direct anti-ferromagnetic bond of strength αL can give rise to three transition temperatures for suitable α. The system passes through ferromagnetic, paramagnetic, anti-ferromagnetic and paramagnetic phases respectively as the temperature is increased. For the square lattice on the other hand, multiple decoration is required to see this effect. We note here that a single decoration suffices for the Ising model on planar random quadrangulations (coupled to 2D quantum gravity). Other random bipartite lattices such as the Penrose tiling are more akin to the regular square lattice and require multiple decoration to have any affect. (author). Letter-to-the-editor

  20. Decorating random quadrangulations

    Johnston, Desmond A. [Department of Mathematics, Heriot-Watt University, Riccarton, Edinburgh (United Kingdom); Malmini, Ranasinghe P.K.C. [Department of Mathematics, University of Sri Jayewardenepura, Gangodawila (Sri Lanka)

    2002-02-22

    On various regular lattices (simple cubic, body centred cubic, etc) decorating an edge with an Ising spin coupled by bonds of strength L to the original vertex spins and competing with a direct anti-ferromagnetic bond of strength {alpha}L can give rise to three transition temperatures for suitable {alpha}. The system passes through ferromagnetic, paramagnetic, anti-ferromagnetic and paramagnetic phases respectively as the temperature is increased. For the square lattice on the other hand, multiple decoration is required to see this effect. We note here that a single decoration suffices for the Ising model on planar random quadrangulations (coupled to 2D quantum gravity). Other random bipartite lattices such as the Penrose tiling are more akin to the regular square lattice and require multiple decoration to have any affect. (author). Letter-to-the-editor.

  1. Beyond Random Assignment

    Eva Lantos Rezmovic; Thomas J. Cook; L. Douglas Dobson

    1981-01-01

    This article draws on the experience gained from conducting a true experiment in the criminal justice field to discuss practical problems in maintaining the integrity of evaluation studies. Issues revolving around budgeting, randomization, data collectors, interview payments, and evaluation of black box treatments are addressed. While these nontechnical aspects of evaluation can significantly affect the validity and meaningfulness of research results, they are rarely discussed in research rep...

  2. a randomized, controlled trial

    Reinecke, Franziska

    2010-01-01

    The polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenism and associated with obesity and impaired glucose metabolism. Despite the high prevalence of PCOS and the considerable clinical impact, the precise interplay between metabolism and hyperandrogenemia is not entirely clear. To analyse the effects of intravenous lipid and heparin infusion on circulating androgen levels in healthy women, we performed a randomized controlled cross-over trial. 12 healthy young women durin...

  3. Randomly Wired Multistage Networks

    Maggs, Bruce M.

    1993-01-01

    Randomly wired multistage networks have recently been shown to outperform traditional multistage networks in three respects. First, they have fast deterministic packet-switching and circuit-switching algorithms for routing permutations. Second, they are nonblocking, and there are on-line algorithms for establishing new connections in them, even if many requests for connections are made simultaneously. Finally, and perhaps most importantly, they are highly fault tolerant.

  4. Random Conformal Weldings

    Astala, K; Kupiainen, A; Saksman, E

    2009-01-01

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle. The homeomorphism is constructed using the exponential of $\\beta X$ where $X$ is the restriction of the two dimensional free field on the circle and the parameter $\\beta$ is in the "high temperature" regime $\\beta<\\sqrt 2$. The welding problem is solved by studying a non-uniformly elliptic Beltrami equation with a random complex dilatation. For the existence a method of Lehto is used. This requires sharp probabilistic estimates to control conformal moduli of annuli and they are proven by decomposing the free field as a sum of independent fixed scale fields and controlling the correlations of the complex dilation restricted to dyadic cells of various scales. For uniqueness we invoke a result by Jones and Smirnov on conformal removability of H\\"older curves. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  5. Quenched moderate deviations principle for random walk in random environment

    2010-01-01

    We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and ergodic.The approach is based on hitting time decomposition.

  6. Random Response of Linear Viscoelastic Systems under Random Excitation

    张天舒; 方同

    2001-01-01

    A method of analyzing random response of linear viscoelastic systems under random excitation has been presented. The covariance matrices of random responses of a single-degree-freedom linear viscoelastic system subjected to stationary white noise and filtered white noise excitations have been obtained in closed form. For illustration, a numerical example has been included. It is observed that viscoelasticity has damping effect on the mean square random responses of the system, the higher is viscoelastic behavior, the higher the damping effect.

  7. ON THE RANGE OF RANDOM WALKS IN RANDOM ENVIRONMENT

    ZHOUXIANYIN

    1995-01-01

    The range of roaldom walk on Zd in symmetric random environment is investigated. As results, it is proved that the strong law of large numbers for the range of random walk oil Zd in some random environments holds if d > 3, and a weak law of large numbers holds for d = 1.

  8. Randomizing Roaches: Exploring the "Bugs" of Randomization in Experimental Design

    Wagler, Amy; Wagler, Ron

    2014-01-01

    Understanding the roles of random selection and random assignment in experimental design is a central learning objective in most introductory statistics courses. This article describes an activity, appropriate for a high school or introductory statistics course, designed to teach the concepts, values and pitfalls of random selection and assignment…

  9. Consistency of Online Random Forests

    Denil, Misha; Matheson, David; De Freitas, Nando

    2013-01-01

    As a testament to their success, the theory of random forests has long been outpaced by their application in practice. In this paper, we take a step towards narrowing this gap by providing a consistency result for online random forests.

  10. Random recursive trees and the elephant random walk

    Kürsten, Rüdiger

    2016-03-01

    One class of random walks with infinite memory, so-called elephant random walks, are simple models describing anomalous diffusion. We present a surprising connection between these models and bond percolation on random recursive trees. We use a coupling between the two models to translate results from elephant random walks to the percolation process. We calculate, besides other quantities, exact expressions for the first and the second moment of the root cluster size and of the number of nodes in child clusters of the first generation. We further introduce another model, the skew elephant random walk, and calculate the first and second moment of this process.

  11. Precise Asymptotics for Random Matrices and Random Growth Models

    Zhong Gen SU

    2008-01-01

    The author considers the largest eigenvalues of random matrices from Gaussian unitary ensemble and Laguerre unitary ensemble, and the rightmost charge in certain random growth models.We obtain some precise asymptotics results, which are in a sense similar to the precise asymptotics for sums of independent random variables in the context of the law of large numbers and complete convergence. Our proofs depend heavily upon the upper and lower tail estimates for random matrices and random growth models. The Tracy-Widom distribution plays a central role as well.

  12. Derandomizing from random strings

    Buhrman, H.; Fortnow, L.; Koucký, Michal; Loff, B.

    Los Alamitos : IEEE Computer Society 2010, 2010, s. 58-63. ISBN 978-0-7695-4060-3. [25th Annual IEEE Conference on Computational Complexity, CCC 2010. Cambridge (US), 09.06.2010-12.06.2010] R&D Projects: GA ČR GAP202/10/0854; GA AV ČR IAA100190902; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : Kolmogorov random strings * reducibility * complexity classes Subject RIV: BA - General Mathematics http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5497897

  13. Random walk loop soup

    Lawler, Gregory F.; Ferreras, José A. Trujillo

    2004-01-01

    The Brownian loop soup introduced in Lawler and Werner (2004) is a Poissonian realization from a sigma-finite measure on unrooted loops. This measure satisfies both conformal invariance and a restriction property. In this paper, we define a random walk loop soup and show that it converges to the Brownian loop soup. In fact, we give a strong approximation result making use of the strong approximation result of Koml\\'os, Major, and Tusn\\'ady. To make the paper self-contained, we include a proof...

  14. Random Web Crawls

    Bennouas, Toufik; de Montgolfier, Fabien

    2007-01-01

    International audience This paper proposes a random Web crawl model. A Web crawl is a (biased and partial) image of the Web. This paper deals with the hyperlink structure, i.e. a Web crawl is a graph, whose vertices are the pages and whose edges are the hypertextual links. Of course a Web crawl has a very special structure; we recall some known results about it. We then propose a model generating similar structures. Our model simply simulates a crawling, i.e. builds and crawls the graph at...

  15. Optimized random chemistry

    Buzas, Jeffrey S.; Warrington, Gregory S.

    2013-01-01

    The random chemistry algorithm of Kauffman can be used to determine an unknown subset S of a fixed set V. The algorithm proceeds by zeroing in on S through a succession of nested subsets V=V_0,V_1,...,V_m=S. In Kauffman's original algorithm, the size of each V_i is chosen to be half the size of V_{i-1}. In this paper we determine the optimal sequence of sizes so as to minimize the expected run time of the algorithm.

  16. Strong Decomposition of Random Variables

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.;

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability of a...... discrete random variable....

  17. Random Numbers and Quantum Computers

    McCartney, Mark; Glass, David

    2002-01-01

    The topic of random numbers is investigated in such a way as to illustrate links between mathematics, physics and computer science. First, the generation of random numbers by a classical computer using the linear congruential generator and logistic map is considered. It is noted that these procedures yield only pseudo-random numbers since…

  18. Investigating the Randomness of Numbers

    Pendleton, Kenn L.

    2009-01-01

    The use of random numbers is pervasive in today's world. Random numbers have practical applications in such far-flung arenas as computer simulations, cryptography, gambling, the legal system, statistical sampling, and even the war on terrorism. Evaluating the randomness of extremely large samples is a complex, intricate process. However, the…

  19. Degenerate random environments

    Holmes, Mark

    2011-01-01

    We consider connectivity properties of certain i.i.d. random environments on $\\Z^d$, where at each location some steps may not be available. Site percolation and oriented percolation can be viewed as special cases of the models we consider. In such models, one of the quantities most often studied is the (random) set of vertices that can be reached from the origin by following a connected path. More generally, for the models we consider, multiple different types of connectivity are of interest, including: the set of vertices that can be reached from the origin; the set of vertices from which the origin can be reached; the intersection of the two. As with percolation models, many of the models we consider admit, or are expected to admit phase transitions. Among the main results of the paper is a proof of the existence of phase transitions for some two-dimensional models that are non-monotone in their underlying parameter, and an improved bound on the critical value for oriented site percolation on the triangula...

  20. Random triangle removal

    Bohman, Tom; Lubetzky, Eyal

    2012-01-01

    Starting from a complete graph on $n$ vertices, repeatedly delete the edges of a uniformly chosen triangle. This stochastic process terminates once it arrives at a triangle-free graph, and the fundamental question is to estimate the final number of edges (equivalently, the time it takes the process to finish, or how many edge-disjoint triangles are packed via the random greedy algorithm). Bollob\\'as and Erd\\H{o}s (1990) conjectured that the expected final number of edges has order $n^{3/2}$. An upper bound of $o(n^2)$ was shown by Spencer (1995) and independently by R\\"odl and Thoma (1996). Several bounds were given for variants and generalizations (e.g., Alon, Kim and Spencer (1997) and Wormald (1999)), while the best known upper bound for the original question of Bollob\\'as and Erd\\H{o}s was $n^{7/4+o(1)}$ due to Grable (1997). No nontrivial lower bound was available. Here we prove that with high probability the final number of edges in random triangle removal is equal to $n^{3/2+o(1)}$, thus confirming the...

  1. Random rectangular Graphs

    Estrada, Ernesto

    2015-01-01

    A generalization of the random geometric graph (RGG) model is proposed by considering a set of points uniformly and independently distributed on a rectangle of unit area instead of on a unit square \\left[0,1\\right]^{2}. The topological properties, such as connectivity, average degree, average path length and clustering, of the random rectangular graphs (RRGs) generated by this model are then studied as a function of the rectangle sides lengths a and b=1/a, and the radius r used to connect the nodes. When a=1 we recover the RGG, and when a\\rightarrow\\infty the very elongated rectangle generated resembles a one-dimensional RGG. We provided computational and analytical evidence that the topological properties of the RRG differ significantly from those of the RGG. The connectivity of the RRG depends not only on the number of nodes as in the case of the RGG, but also on the side length of the rectangle. As the rectangle is more elongated the critical radius for connectivity increases following first a power-law an...

  2. Randomness in Competitions

    Ben-Naim, E; Redner, S; Vazquez, F

    2012-01-01

    We study the effects of randomness on competitions based on an elementary random process in which there is a finite probability that a weaker team upsets a stronger team. We apply this model to sports leagues and sports tournaments, and compare the theoretical results with empirical data. Our model shows that single-elimination tournaments are efficient but unfair: the number of games is proportional to the number of teams N, but the probability that the weakest team wins decays only algebraically with N. In contrast, leagues, where every team plays every other team, are fair but inefficient: the top $\\sqrt{N}$ of teams remain in contention for the championship, while the probability that the weakest team becomes champion is exponentially small. We also propose a gradual elimination schedule that consists of a preliminary round and a championship round. Initially, teams play a small number of preliminary games, and subsequently, a few teams qualify for the championship round. This algorithm is fair and effici...

  3. Pilot study of a 10-week multidisciplinary Tai Chi intervention in sedentary obese women.

    Dechamps, A.A.; Gatta, B.; Bourdel-Marchasson, I.; Tabarin, A.; Roger, P.

    2009-01-01

    OBJECTIVE: Alternative approaches to weight control and physical activity are increasingly needed. Numerous factors influence weight management, including the choice of physical exercise. No study has previously examined the therapeutic effect of a multidisciplinary weight management program incorpo

  4. Impact of 10-weeks of yoga practice on flexibility and balance of college athletes

    M Jay Polsgrove

    2016-01-01

    Conclusions: Results suggest that a regular yoga practice may increase the flexibility and balance as well as whole body measures of male college athletes and therefore, may enhance athletic performances that require these characteristics.

  5. HP-PRRSV challenge of 4 and 10-week-old pigs

    In 2006 a unique syndrome was recognized in growing pigs in China with the predominant clinical signs being high fever, anorexia, listlessness, red discoloration of skin, and respiratory distress. The disease had a very high morbidity and mortality rate and became known as porcine high fever disease...

  6. Acute and medium term effects of a 10-week running intervention on mood state in apprentices

    Walter, Katrin; von Haaren, Birte; Löffler, Simone; Härtel, Sascha; Jansen, Carl-Philipp; Werner, Christian; Stumpp, Jürgen; Bös, Klaus; Hey, Stefan

    2013-01-01

    Exercise and physical activity have proven benefits for physical and psychological well-being. However, it is not clear if healthy young adults can enhance mood in everyday life through regular exercise. Earlier studies mainly showed positive effects of acute exercise and exercise programs on psychological well-being in children, older people and in clinical populations. Few studies controlled participants' physical activity in daily life, performed besides the exercise program, which can imp...

  7. Clinical correlates of weight loss and attrition during a 10-week dietary intervention study

    Handjieva-Darlenska, Teodora; Holst, Claus; Grau, Katrine;

    2012-01-01

    + 1.35 × gender (R(2) = 0.28, p <0.001). When performing the corresponding model with half-way weight loss (week 5) as covariate, the regression equation was: weight loss (kg) at week 10 = 1.88 + 1.38 × half-way weight loss (kg) (week 5) + 0.42 × gender (R(2) = 0.77, p <0.001). A cut-off target of = 4...

  8. Solid-State Random Lasers

    Noginov, Mikhail A

    2005-01-01

    Random lasers are the simplest sources of stimulated emission without cavity, with the feedback provided by scattering in a gain medium. First proposed in the late 60’s, random lasers have grown to a large research field. This book reviews the history and the state of the art of random lasers, provides an outline of the basic models describing their behavior, and describes the recent advances in the field. The major focus of the book is on solid-state random lasers. However, it also briefly describes random lasers based on liquid dyes with scatterers. The chapters of the book are almost independent of each other. So, the scientists or engineers interested in any particular aspect of random lasers can read directly the relevant section. Researchers entering the field of random lasers will find in the book an overview of the field of study. Scientists working in the field can use the book as a reference source.

  9. Investments in random environments

    Navarro-Barrientos, Jesús Emeterio; Cantero-Álvarez, Rubén; Matias Rodrigues, João F.; Schweitzer, Frank

    2008-03-01

    We present analytical investigations of a multiplicative stochastic process that models a simple investor dynamics in a random environment. The dynamics of the investor's budget, x(t) , depends on the stochasticity of the return on investment, r(t) , for which different model assumptions are discussed. The fat-tail distribution of the budget is investigated and compared with theoretical predictions. We are mainly interested in the most probable value xmp of the budget that reaches a constant value over time. Based on an analytical investigation of the dynamics, we are able to predict xmpstat . We find a scaling law that relates the most probable value to the characteristic parameters describing the stochastic process. Our analytical results are confirmed by stochastic computer simulations that show a very good agreement with the predictions.

  10. Aging Random Walks

    Böttcher, S

    1997-01-01

    Aging refers to the property of two-time correlation functions to decay very slowly on (at least) two time scales. This phenomenon has gained recent attention due to experimental observations of the history dependent relaxation behavior in amorphous materials (``Glasses'') which pose a challenge to theorist. Aging signals the breaking of time-translational invariance and the violation of the fluctuation dissipation theorem during the relaxation process. But while the origin of aging in disordered media is profound, and the discussion is clad in the language of a well-developed theory, systems as simple as a random walk near a wall can exhibit aging. Such a simple walk serves well to illustrate the phenomenon and some of the physics behind it.

  11. Associative Hierarchical Random Fields.

    Ladický, L'ubor; Russell, Chris; Kohli, Pushmeet; Torr, Philip H S

    2014-06-01

    This paper makes two contributions: the first is the proposal of a new model-The associative hierarchical random field (AHRF), and a novel algorithm for its optimization; the second is the application of this model to the problem of semantic segmentation. Most methods for semantic segmentation are formulated as a labeling problem for variables that might correspond to either pixels or segments such as super-pixels. It is well known that the generation of super pixel segmentations is not unique. This has motivated many researchers to use multiple super pixel segmentations for problems such as semantic segmentation or single view reconstruction. These super-pixels have not yet been combined in a principled manner, this is a difficult problem, as they may overlap, or be nested in such a way that the segmentations form a segmentation tree. Our new hierarchical random field model allows information from all of the multiple segmentations to contribute to a global energy. MAP inference in this model can be performed efficiently using powerful graph cut based move making algorithms. Our framework generalizes much of the previous work based on pixels or segments, and the resulting labelings can be viewed both as a detailed segmentation at the pixel level, or at the other extreme, as a segment selector that pieces together a solution like a jigsaw, selecting the best segments from different segmentations as pieces. We evaluate its performance on some of the most challenging data sets for object class segmentation, and show that this ability to perform inference using multiple overlapping segmentations leads to state-of-the-art results. PMID:26353271

  12. Importance of randomness in biological networks: A random matrix analysis

    Sarika Jalan

    2015-02-01

    Random matrix theory, initially proposed to understand the complex interactions in nuclear spectra, has demonstrated its success in diverse domains of science ranging from quantum chaos to galaxies. We demonstrate the applicability of random matrix theory for networks by providing a new dimension to complex systems research. We show that in spite of huge differences these interaction networks, representing real-world systems, posses from random matrix models, the spectral properties of the underlying matrices of these networks follow random matrix theory bringing them into the same universality class. We further demonstrate the importance of randomness in interactions for deducing crucial properties of the underlying system. This paper provides an overview of the importance of random matrix framework in complex systems research with biological systems as examples.

  13. Random allocation software for parallel group randomized trials

    Saghaei Mahmood

    2004-01-01

    Abstract Background Typically, randomization software should allow users to exert control over the different aspects of randomization including block design, provision of unique identifiers and control over the format and type of program output. While some of these characteristics have been addressed by available software, none of them have all of these capabilities integrated into one package. The main objective of the Random Allocation Software project was to enhance the user's control over...

  14. RENEWAL THEOREM FOR (L, 1)-RANDOM WALK IN RANDOM ENVIRONMENT

    洪文明; 孙鸿雁

    2013-01-01

    We consider a random walk on Z in random environment with possible jumps{-L, · · · ,-1, 1}, in the case that the environment{ωi: i∈Z}are i.i.d.. We establish the renewal theorem for the Markov chain of “the environment viewed from the particle” in both annealed probability and quenched probability, which generalize partially the results of Kesten (1977) and Lalley (1986) for the nearest random walk in random environment on Z, respectively. Our method is based on the intrinsic branching structure within the (L, 1)-RWRE formulated in Hong and Wang (2013).

  15. The HIKCUPS trial: a multi-site randomized controlled trial of a combined physical activity skill-development and dietary modification program in overweight and obese children

    Warren Janet M

    2007-01-01

    Full Text Available Abstract Background Childhood obesity is one of the most pressing health issues of our time. Key health organizations have recommended research be conducted on the effectiveness of well-designed interventions to combat childhood obesity that can be translated into a variety of settings. This paper describes the design and methods used in the Hunter Illawarra Kids Challenge Using Parent Support (HIKCUPS trial, an ongoing multi-site randomized controlled trial, in overweight/obese children comparing the efficacy of three interventions: 1 a parent-centered dietary modification program; 2 a child-centered physical activity skill-development program; and 3 a program combining both 1 and 2 above. Methods/Design Each intervention consists of three components: i 10-weekly face-to-face group sessions; ii a weekly homework component, completed between each face-to-face session and iii three telephone calls at monthly intervals following completion of the 10-week program. Details of the programs' methodological aspects of recruitment, randomization and statistical analyses are described here a priori. Discussion Importantly this paper describes how HIKCUPS addresses some of the short falls in the current literature pertaining to the efficacy of child obesity interventions. The HIKCUPS trial is funded by the National Medical Research Council, Australia.

  16. Fractional random walk lattice dynamics

    Michelitsch, Thomas; Riascos, Alejandro Perez; Nowakowski, Andrzeij; Nicolleau, Franck

    2016-01-01

    We analyze time-discrete and continuous `fractional' random walks on undirected regular networks with special focus on cubic periodic lattices in $n=1,2,3,..$ dimensions.The fractional random walk dynamics is governed by a master equation involving {\\it fractional powers of Laplacian matrices $L^{\\frac{\\alpha}{2}}$}where $\\alpha=2$ recovers the normal walk.First we demonstrate thatthe interval $0\\textless{}\\alpha\\leq 2$ is admissible for the fractional random walk. We derive analytical expressions for fractional transition matrix and closely related the average return probabilities. We further obtain thefundamental matrix $Z^{(\\alpha)}$, and the mean relaxation time (Kemeny constant) for the fractional random walk.The representation for the fundamental matrix $Z^{(\\alpha)}$ relates fractional random walks with normal random walks.We show that the fractional transition matrix elements exihibit for large cubic $n$-dimensional lattices a power law decay of an $n$-dimensional infinite spaceRiesz fractional deriva...

  17. Correlação do volume da vesícula vitelínica obtida por meio da ultrassonografia tridimensional com a idade gestacional entre a 7ª e a 10ª semanas usando o método multiplanar Correlation of yolk sac volume obtained by three-dimensional ultrasonography with the gestational age at 7-10 weeks utilizing the multiplanar method

    Liliam Cristine Rolo

    2009-12-01

    Full Text Available OBJETIVO: Avaliar a correlação do volume da vesícula vitelínica aferida por meio da ultrassonografia tridimensional com a idade gestacional entre a 7ª e a 10ª semanas. MATERIAIS E MÉTODOS: Realizou-se um estudo do tipo corte transversal envolvendo 72 gestantes normais entre a 7ª e a 10ª semanas de gestação. Para o cálculo do volume da vesícula vitelínica, utilizou-se o método multiplanar com intervalo de 1,0 mm entre os planos. Para o volume da vesícula vitelínica foram determinadas médias, medianas, desvios-padrão e valores máximo e mínimo. Para avaliar a correlação entre o volume da vesícula vitelínica e a idade gestacional, foram criados modelos de regressão, sendo os ajustes realizados pelo coeficiente de determinação (R². RESULTADOS: O volume da vesícula vitelínica (VV mostrou-se fracamente correlacionado com a idade gestacional (IG, melhor representado pela regressão quadrática, representada pela equação: volume VV = 0,9757 - 0,2499 × IG + 0,0172 × IG² (R² = 0,234. O volume médio da vesícula vitelínica variou de 0,07 cm³ (0,02-0,11 a 0,20 cm³ (0,02-0,74 entre a 7ª e a 10ª semanas de gestação, com média de 0,11 cm³ (± 0,10 cm³. CONCLUSÃO: O volume da vesícula vitelínica correlacionou-se fracamente com a idade gestacional.OBJECTIVE: To evaluate the correlation between the yolk sac volume measured by three-dimensional ultrasonography with gestational age at 7-10 weeks. MATERIALS AND METHODS: A cross-sectional study involving 72 healthy pregnant women at 7th-10th gestational weeks. The multiplanar method with 1.0 mm intervals was utilized. Regression models were constructed to analyze the correlation between yolk sac volume and gestational age, adjusted by the determination coefficient (R². Mean, median, standard deviation, maximum and minimum values for yolk sac volume were calculated for each gestational age. RESULTS: A poor correlation was observed between yolk sac volume (YSV and

  18. Networks, Random Graphs and Percolation

    Deprez, Philippe; Wüthrich, Mario V.

    2014-01-01

    The theory of random graphs goes back to the late 1950s when Paul Erd\\H{o}s and Alfr\\'ed R\\'enyi introduced the Erd\\H{o}s-R\\'enyi random graph. Since then many models have been developed, and the study of random graph models has become popular for real-life network modelling such as social networks and financial networks. The aim of this overview is to review relevant random graph models for real-life network modelling. Therefore, we analyse their properties in terms of stylised facts of real...

  19. Resistance random access memory

    Ting-Chang Chang

    2016-06-01

    Full Text Available Non-volatile memory (NVM will play a decisive role in the development of the next-generation of electronic products. Therefore, the development of next-generation NVM is urgent as widely applied flash memory is facing its physical limit. Among various next-generation NVMs, Resistive Random Access Memory (RRAM is a promising candidate for future memory due to its high-efficiency, high-speed and energy-saving characteristics. In recent years, continuous improvement and in-depth investigation in both materials and electrical switching mechanisms have not only lead to a breakthrough in the performance of digital NVM, but also lead to other possible memory functionality. This paper describes new findings and perspectives on various RRAM devices with different laminated structures and materials, and classifies RRAM into four categories according to different resistive switching mechanisms, from which the four elements are (1 anion-type RRAM: redox reaction and migration of oxygen ions, (2 cation-type RRAM: redox reaction and migration of cation ions, (3 carbon-based RRAM: the stretch of CC bond lengths due to oxygen and hydrogen dual ions, (4 oxide-based electrode: oxygen accumulation in oxide-based electrode.

  20. Ferroelectric random access memories.

    Ishiwara, Hiroshi

    2012-10-01

    Ferroelectric random access memory (FeRAM) is a nonvolatile memory, in which data are stored using hysteretic P-E (polarization vs. electric field) characteristics in a ferroelectric film. In this review, history and characteristics of FeRAMs are first introduced. It is described that there are two types of FeRAMs, capacitor-type and FET-type, and that only the capacitor-type FeRAM is now commercially available. In chapter 2, properties of ferroelectric films are discussed from a viewpoint of FeRAM application, in which particular attention is paid to those of Pb(Zr,Ti)O3, SrBi2Ta2O9, and BiFeO3. Then, cell structures and operation principle of the capacitor-type FeRAMs are discussed in chapter 3. It is described that the stacked technology of ferroelectric capacitors and development of new materials with large remanent polarization are important for fabricating high-density memories. Finally, in chapter 4, the optimized gate structure in ferroelectric-gate field-effect transistors is discussed and experimental results showing excellent data retention characteristics are presented. PMID:23421123

  1. Random eigenvalue problems revisited

    S Adhikari

    2006-08-01

    The description of real-life engineering structural systems is associated with some amount of uncertainty in specifying material properties, geometric parameters, boundary conditions and applied loads. In the context of structural dynamics it is necessary to consider random eigenvalue problems in order to account for these uncertainties. Within the engineering literature, current methods to deal with such problems are dominated by approximate perturbation methods. Some exact methods to obtain joint distribution of the natural frequencies are reviewed and their applicability in the context of real-life engineering problems is discussed. A new approach based on an asymptotic approximation of multi-dimensional integrals is proposed. A closed-form expression for general order joint moments of arbitrary numbers of natural frequencies of linear stochastic systems is derived. The proposed method does not employ the ‘small randomness’ assumption usually used in perturbation based methods. Joint distributions of the natural frequencies are investigated using numerical examples and the results are compared with Monte Carlo simulation.

  2. Compressed random access memory

    Jansson, Jesper; Sung, Wing-Kin

    2010-01-01

    Motivated by applications which need to store huge amounts of data in the main memory of a computer, this paper proposes a new dynamic data-structure for compressed random access memory. Ferragina and Venturini [SODA 2007, TCS 2007] recently gave a compressed data-structure for storing a string that allows substrings to be retrieved efficiently, but it requires the string to be static. Here, we extend their results in a non-trivial way to also allow the stored compressed string to be modified during execution. Our results are as follows. A memory (or string) $T[1..n]$, where each character $T[i]$ is of $\\log\\sigma$ bits, can be stored in $n H_k(T) + O(n \\log \\sigma \\frac{(k+1) (\\log \\sigma +\\log \\log n)}{\\log n})$ bits, where $H_k(T)$ is the $k$-th order empirical entropy of $T$, such that (1) accessing $T[i..j]$ takes optimal $O(1 + (j-i) / \\log_{\\sigma} n)$ time and (2) replacing $T[i..i+\\log_{\\sigma} n - 1]$ by another string of length $\\log_{\\sigma} n$ takes $O(\\log n/\\log\\log n)$ time. We can also suppor...

  3. Randomness-optimal Steganography

    Kiayias, Aggelos; Shashidhar, Narasimha

    2009-01-01

    Steganographic protocols enables one to "embed" covert messages into inconspicous data over a public communication channel in such a way that no one, aside from the sender and the intended receiver can even detect the presence of the secret message. In this paper, we provide a new provably-secure, private-key steganographic encryption protocol. We prove the security of our protocol in the complexity-theoretic framework where security is quantified as the advantage (compared to a random guess) that the adversary has in distinguishing between innocent covertext and stegotext that embeds a message of his choice. The fundamental building block of our steganographic encryption protocol is a "one-time stegosystem" that allows two parties to transmit messages of length at most that of the shared key with information-theoretic security guarantees. The employment of a pseudorandom generator (PRG) permits secure transmission of longer messages in the same way that such a generator allows the use of one-time pad encrypt...

  4. Random walkers versus random crowds: diffusion of large matrices

    Gudowska-Nowak, Ewa; Janik, Romuald J.; Jurkiewicz, Jerzy; Nowak, Maciej A.; Wieczorek, Waldemar

    2006-01-01

    We briefly review the random matrix theory for large N by N matrices viewed as free random variables in a context of stochastic diffusion. We establish a surprising link between the spectral properties of matrix-valued multiplicative diffusion processes for hermitian and unitary ensembles.

  5. Random allocation software for parallel group randomized trials

    Saghaei Mahmood

    2004-11-01

    Full Text Available Abstract Background Typically, randomization software should allow users to exert control over the different aspects of randomization including block design, provision of unique identifiers and control over the format and type of program output. While some of these characteristics have been addressed by available software, none of them have all of these capabilities integrated into one package. The main objective of the Random Allocation Software project was to enhance the user's control over different aspects of randomization in parallel group trials, including output type and format, structure and ordering of generated unique identifiers and enabling users to specify group names for more than two groups. Results The program has different settings for: simple and blocked randomizations; length, format and ordering of generated unique identifiers; type and format of program output; and saving sessions for future use. A formatted random list generated by this program can be used directly (without further formatting by the coordinator of the research team to prepare and encode different drugs or instruments necessary for the parallel group trial. Conclusions Random Allocation Software enables users to control different attributes of the random allocation sequence and produce qualified lists for parallel group trials.

  6. Pseudo-random number generator based on asymptotic deterministic randomness

    A novel approach to generate the pseudorandom-bit sequence from the asymptotic deterministic randomness system is proposed in this Letter. We study the characteristic of multi-value correspondence of the asymptotic deterministic randomness constructed by the piecewise linear map and the noninvertible nonlinearity transform, and then give the discretized systems in the finite digitized state space. The statistic characteristics of the asymptotic deterministic randomness are investigated numerically, such as stationary probability density function and random-like behavior. Furthermore, we analyze the dynamics of the symbolic sequence. Both theoretical and experimental results show that the symbolic sequence of the asymptotic deterministic randomness possesses very good cryptographic properties, which improve the security of chaos based PRBGs and increase the resistance against entropy attacks and symbolic dynamics attacks

  7. Phase transitions on random lattices: how random is topological disorder?

    Barghathi, Hatem; Vojta, Thomas

    2014-09-19

    We study the effects of topological (connectivity) disorder on phase transitions. We identify a broad class of random lattices whose disorder fluctuations decay much faster with increasing length scale than those of generic random systems, yielding a wandering exponent of ω=(d-1)/(2d) in d dimensions. The stability of clean critical points is thus governed by the criterion (d+1)ν>2 rather than the usual Harris criterion dν>2, making topological disorder less relevant than generic randomness. The Imry-Ma criterion is also modified, allowing first-order transitions to survive in all dimensions d>1. These results explain a host of puzzling violations of the original criteria for equilibrium and nonequilibrium phase transitions on random lattices. We discuss applications, and we illustrate our theory by computer simulations of random Voronoi and other lattices. PMID:25279615

  8. Random distributed feedback fibre lasers

    The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

  9. Fields on a random lattice

    We review the formulation of field theory and statistical mechanics on a Poissonian random lattice. Topics discussed include random geometry, the construction of field equations for arbitrary spin, the free field spectrum and the question of localization illustrated in the one dimensional case

  10. WEAK UNCORRELATEDNESS OF RANDOM VARIABLES

    Sofiya Ostrovska

    2006-01-01

    New measures of independence for n random variables, based on their moments, are studied. A scale of degrees of independence for random variables which starts with uncorrelatedness (for n = 2) and finishes at independence is constructed. The scale provides a countable linearly ordered set of measures of independence.

  11. Ticks of a Random clock

    Jung, P.; Talkner, P.

    2010-09-01

    A simple way to convert a purely random sequence of events into a signal with a strong periodic component is proposed. The signal consists of those instants of time at which the length of the random sequence exceeds an integer multiple of a given number. The larger this number the more pronounced the periodic behavior becomes.

  12. Quantum to Classical Randomness Extractors

    Berta, Mario; Wehner, Stephanie

    2011-01-01

    Even though randomness is an essential resource for many information processing tasks, it is not easily found in nature. The goal of randomness extraction is to distill (almost) perfect randomness from a weak source of randomness. When the source yields a classical string X, many extractor constructions are known. Yet, when considering a physical randomness source, X is itself ultimately the result of a measurement on an underlying quantum system. When characterizing the power of a source to supply randomness it is hence a natural question to ask, how much classical randomness we can extract from a quantum state. To tackle this question we here take on the study of quantum-to-classical randomness extractors (QC-extractors). We provide constructions of QC-extractors based on measurements in a full set of mutually unbiased bases (MUBs), and certain single qubit measurements. As the first application, we show that any QC-extractor gives rise to entropic uncertainty relations with respect to quantum side informat...

  13. Markov Random Field Surface Reconstruction

    Paulsen, Rasmus Reinhold; Bærentzen, Jakob Andreas; Larsen, Rasmus

    2010-01-01

    A method for implicit surface reconstruction is proposed. The novelty in this paper is the adaption of Markov Random Field regularization of a distance field. The Markov Random Field formulation allows us to integrate both knowledge about the type of surface we wish to reconstruct (the prior) and...

  14. Students' Misconceptions about Random Variables

    Kachapova, Farida; Kachapov, Ilias

    2012-01-01

    This article describes some misconceptions about random variables and related counter-examples, and makes suggestions about teaching initial topics on random variables in general form instead of doing it separately for discrete and continuous cases. The focus is on post-calculus probability courses. (Contains 2 figures.)

  15. Local Interaction on Random Graphs

    Hans Haller

    2010-08-01

    Full Text Available We analyze dynamic local interaction in population games where the local interaction structure (modeled as a graph can change over time: A stochastic process generates a random sequence of graphs. This contrasts with models where the initial interaction structure (represented by a deterministic graph or the realization of a random graph cannot change over time.

  16. Treatment of myofascial trigger points in female patients with chronic tension-type headache - A randomized controlled trial

    Berggreen, S.; Wiik, E.; Lund, Hans

    2012-01-01

    The aim of this study was to evaluate the efficacy of myofascial trigger point massage in the muscles of the head, neck and shoulders regarding pain in the treatment of females with chronic tension-type headache. They were randomized into either a treatment group (n = 20) (one session of trigger...... point massage per week for 10 weeks) or a control group receiving no treatment (n = 19). The patients kept a diary to record their pain on a visual analogue scale (VAS), and the daily intake of drugs (mg) during the 4 weeks before and after the treatment period. The McGill Pain Questionnaire and the......: 8.8 (95% CI 0.1117.4), p = 0.047). Furthermore, a significant decrease in the number of trigger points was observed in the treatment group compared with the control group. Myofascial trigger point massage has a beneficial effect on pain in female patients with chronic tension-type headache. © 2012...

  17. Levy flights and random searches

    In this work we discuss some recent contributions to the random search problem. Our analysis includes superdiffusive Levy processes and correlated random walks in several regimes of target site density, mobility and revisitability. We present results in the context of mean-field-like and closed-form average calculations, as well as numerical simulations. We then consider random searches performed in regular lattices and lattices with defects, and we discuss a necessary criterion for distinguishing true superdiffusion from correlated random walk processes. We invoke energy considerations in relation to critical survival states on the edge of extinction, and we analyze the emergence of Levy behavior in deterministic search walks. Finally, we comment on the random search problem in the context of biological foraging.

  18. The efficacy of extended-release levomilnacipran in moderate to severe major depressive disorder: secondary and post-hoc analyses from a randomized, double-blind, placebo-controlled study

    Montgomery, Stuart A.; Mansuy, Lucilla; Ruth, Adam C.; Li, Dayong; Gommoll, Carl

    2013-01-01

    Levomilnacipran (1S, 2R-milnacipran) is a potent and selective serotonin and norepinephrine reuptake inhibitor that is Food and Drug Administration approved for once-daily treatment of major depressive disorder in adults. Secondary and post-hoc analyses were carried out on data from a positive 10-week, randomized, double-blind, placebo-controlled, parallel-group, multicenter, proof-of-concept trial (EudraCT Number: 2006-002404-34) on 75 or 100 mg/day levomilnacipran extended release (ER). Inc...

  19. Delocalization for Random Landau Hamiltonians with Unbounded Random Variables

    Germinet, François; Mandy, Benoît

    2009-01-01

    In this note we prove the existence of a localization/delocalization transition for Landau Hamiltonians randomly perturbed by an electric potential with unbounded amplitude. In particular, with probability one, no Landau gaps survive as the random potential is turned on, the gaps close, filling up partly with localized states. A minimal rate of transport is exhibited in the region of delocalization. To do so, we exploit the a priori quantization of the Hall conductance and extend recent Wegner estimates to the case of unbounded random variables.

  20. Topiramate for the management of methamphetamine dependence: a pilot randomized, double-blind, placebo-controlled trial.

    Rezaei, Farzin; Ghaderi, Ebrahim; Mardani, Roya; Hamidi, Seiran; Hassanzadeh, Kambiz

    2016-06-01

    To date, no medication has been approved as an effective treatment for methamphetamine dependence. Topiramate has attracted considerable attention as a treatment for the dependence on alcohol and stimulants. Therefore, this study aimed to evaluate the effect of topiramate for methamphetamine dependence. This study was a double-blind, randomized, placebo-controlled trial. In the present investigation, 62 methamphetamine-dependent adults were enrolled and randomized into two groups, and received topiramate or a placebo for 10 weeks in escalating doses from 50 mg/day to the target maintenance dose of 200 mg/day. Addiction severity index (ASI) and craving scores were registered every week. The Beck questionnaire was also given to each participant at baseline and every 2 weeks during the treatment. Urine samples were collected at baseline and every 2 weeks during the treatment. Fifty-seven patients completed 10 weeks of the trial. There was no significant difference between both groups in the mean percentage of prescribed capsules taken by the participants. At week six, the topiramate group showed a significantly lower proportion of methamphetamine-positive urine tests in comparison with the placebo group (P = 0.01). In addition, there were significantly lower scores in the topiramate group in comparison with the placebo group in two domains of ASI: drug use severity (P < 0.001) and drug need (P < 0.001). Furthermore, the craving score (duration) significantly declined in the topiramate patients compared to those receiving the placebo. In conclusion, the results of this trial suggest that topiramate may be beneficial for the treatment of methamphetamine dependence. PMID:26751259

  1. Mental skills training with basic combat training soldiers: A group-randomized trial.

    Adler, Amy B; Bliese, Paul D; Pickering, Michael A; Hammermeister, Jon; Williams, Jason; Harada, Coreen; Csoka, Louis; Holliday, Bernie; Ohlson, Carl

    2015-11-01

    Cognitive skills training has been linked to greater skills, self-efficacy, and performance. Although research in a variety of organizational settings has demonstrated training efficacy, few studies have assessed cognitive skills training using rigorous, longitudinal, randomized trials with active controls. The present study examined cognitive skills training in a high-risk occupation by randomizing 48 platoons (N = 2,432 soldiers) in basic combat training to either (a) mental skills training or (b) an active comparison condition (military history). Surveys were conducted at baseline and 3 times across the 10-week course. Multilevel mixed-effects models revealed that soldiers in the mental skills training condition reported greater use of a range of cognitive skills and increased confidence relative to those in the control condition. Soldiers in the mental skills training condition also performed better on obstacle course events, rappelling, physical fitness, and initial weapons qualification scores, although effects were generally moderated by gender and previous experience. Overall, effects were small; however, given the rigor of the design, the findings clearly contribute to the broader literature by providing supporting evidence that cognitive training skills can enhance performance in occupational and sports settings. Future research should address gender and experience to determine the need for targeting such training appropriately. PMID:26011718

  2. Acupuncture Antiarrhythmic Effects on Drug Refractory Persistent Atrial Fibrillation: Study Protocol for a Randomized, Controlled Trial

    Jimin Park

    2015-01-01

    Full Text Available Background. Atrial fibrillation (AF is the most common form of arrhythmia. Several trials have suggested that acupuncture may prevent AF. However, the efficacy of acupuncture for AF prevention has not been well investigated. Therefore, we designed a prospective, two-parallel-armed, participant and assessor blinded, randomized, sham-controlled clinical trial to investigate acupuncture in persistent AF (ACU-AF. Methods. A total of 80 participants will be randomly assigned to active acupuncture or sham acupuncture groups in a 1 : 1 ratio. Both groups will take the same antiarrhythmic medication during the study period. Patients will receive 10 sessions of acupuncture treatment once a week for 10 weeks. The primary endpoint is AF recurrence rate. Secondary endpoints are left atrium (LA and left atrial appendage (LAA changes in function and volume, and inflammatory biomarker changes. Ethics. This study protocol was approved by the institutional review boards (IRBs of Kyung Hee University Hospital (number 1335-04. This trial is registered with clinicaltrials.gov NCT02110537.

  3. Spectral Properties of Random Reactance Networks and Random Matrix Pencils

    Fyodorov, Yan V

    1999-01-01

    Our goal is to study statistical properies of "dielectric resonances" which are poles of conductance of a large random $LC$ network. Such poles are a particular example of eigenvalues $\\lambda_n$ of matrix pencils ${\\bf H}-\\lambda {\\bf W}$, with ${\\bf W}$ being positive definite matrix and ${\\bf H}$ a random real symmetric one. We first consider spectra of matrix pencils with independent, identically distributed entries of ${\\bf H}$. Then we concentrate on an infinite-range ("full-connectivit...

  4. RANDOM, Random Number Generator with Large Cycle Length

    1 - Description of problem or function: RANDOM is a portable pseudo- random number generator with a cycle length exceeding 2.78 * 1013. 2 - Method of solution: Three simple multiplicative congruential generators are used. Each one uses a prime number for its modulus and a primitive root for its multiplier. 3 - Restrictions on the complexity of the problem: Integer arithmetic up to 30323 is required

  5. Relative Complexity of random walks in random sceneries

    Aaronson, Jon

    2010-01-01

    Relative complexity measures the complexity of a probability preserving transformation relative to a factor being a sequence of random variables whose exponential growth rate is the relative entropy of the extension. We prove distributional limit theorems for the relative complexity of certain zero entropy extensions: RWRSs whose associated random walks satisfy the alpha-stable CLT (alpha>1). The results give invariants for relative isomorphism of these.

  6. Random processes in nuclear reactors

    Williams, M M R

    1974-01-01

    Random Processes in Nuclear Reactors describes the problems that a nuclear engineer may meet which involve random fluctuations and sets out in detail how they may be interpreted in terms of various models of the reactor system. Chapters set out to discuss topics on the origins of random processes and sources; the general technique to zero-power problems and bring out the basic effect of fission, and fluctuations in the lifetime of neutrons, on the measured response; the interpretation of power reactor noise; and associated problems connected with mechanical, hydraulic and thermal noise sources

  7. Guiding Synchrony through Random Networks

    Jahnke, Sven; Timme, Marc; Memmesheimer, Raoul-Martin

    2012-10-01

    Sparse random networks contain structures that can be considered as diluted feed-forward networks. Modeling of cortical circuits has shown that feed-forward structures, if strongly pronounced compared to the embedding random network, enable reliable signal transmission by propagating localized (subnetwork) synchrony. This assumed prominence, however, is not experimentally observed in local cortical circuits. Here, we show that nonlinear dendritic interactions, as discovered in recent single-neuron experiments, naturally enable guided synchrony propagation already in random recurrent neural networks that exhibit mildly enhanced, biologically plausible substructures.

  8. High Entropy Random Selection Protocols

    Buhrman, H.; Christandl, M.; Koucký, Michal; Lotker, Z.; Patt-Shamir, B.; Vereshchagin, N.K.

    Berlin: Springer-Verlag, 2007 - (Charikar, M.; Jansen, K.; Reingold, O.; Rolim, J.), s. 366-379. (Lecture Notes in Computer Science. 4627). ISBN 978-3-540-74207-4. [International Workshop on Approximation Algorithms for Combinatorial Optimization Problems/10./, and International Workshop on Randomization and Computation/11./, RANDOM-APPROX 2007. Princeton (US), 20.08.2007-22.08.2007] R&D Projects: GA ČR GA201/05/0124; GA ČR GP201/07/P276 Institutional research plan: CEZ:AV0Z10190503 Keywords : random string selection * cryptography * Kakeya problem Subject RIV: BA - General Mathematics

  9. Symmetrization of binary random variables

    Kagan, Abram; Mallows, Colin L.; Shepp, Larry A.; Vanderbei, Robert J.; Vardi, Yehuda

    1999-01-01

    A random variable [math] is called an independent symmetrizer of a given random variable [math] if (a) it is independent of [math] and (b) the distribution of [math] is symmetric about [math] . In cases where the distribution of [math] is symmetric about its mean, it is easy to see that the constant random variable [math] is a minimum-variance independent symmetrizer. Taking [math] to have the same distribution as [math] clearly produces a symmetric sum, but it may not be of minimum variance....

  10. Covariate-based constrained randomization of group-randomized trials.

    Moulton, Lawrence H

    2004-01-01

    Group-randomized study designs are useful when individually randomized designs are either not possible, or will not be able to estimate the parameters of interest. Blocked and/or stratified (for example, pair-matched) designs have been used, and their properties statistically evaluated by many researchers. Group-randomized trials often have small numbers of experimental units, and strong, geographically induced between-unit correlation, which increase the chance of obtaining a "bad" randomization outcome. This article describes a procedure--random selection from a list of acceptable allocations--to allocate treatment conditions in a way that ensures balance on relevant covariates. Numerous individual- and group-level covariates can be balanced using exact or caliper criteria. Simulation results indicate that this method has good frequency properties, but some care may be needed not to overly constrain the randomization. There is a trade-off between achieving good balance through a highly constrained design, and jeopardizing the appearance of impartiality of the investigator and potentially departing from the nominal Type I error. PMID:16279255

  11. Percolation properties of random ellipses

    We compute the percolation concentration for identical ellipses with aspect ratio b/a in a two-dimensional plane where both the centers and orientations are random. We have obtained a comprehensive set of results ranging from circles to needles which can be well fit by the interpolation formula p/sub c/ = (1+4y)/(19+4y), where y = b/a+a/b. We also obtain results for random centers and random orientations along the two principal directions which are virtually indistinguishable from the previous case. These results are used to critique the various effective-medium theories that have been developed for the electrical conductance and elastic moduli of sheets containing random elliptical inclusions. An interpolation formula is developed that appears superior to all these effective-medium theories

  12. Random Distances Associated with Rhombuses

    Zhuang, Yanyan

    2011-01-01

    Parallelograms are one of the basic building blocks in two-dimensional tiling. They have important applications in a wide variety of science and engineering fields, such as wireless communication networks, urban transportation, operations research, etc. Different from rectangles and squares, the coordinates of a random point in parallelograms are no longer independent. As a case study of parallelograms, the explicit probability density functions of the random Euclidean distances associated with rhombuses are given in this report, when both endpoints are randomly distributed in 1) the same rhombus, 2) two parallel rhombuses sharing a side, and 3) two rhombuses having a common diagonal, respectively. The accuracy of the distance distribution functions is verified by simulation, and the correctness is validated by a recursion and a probabilistic sum. The first two statistical moments of the random distances, and the polynomial fit of the density functions are also given in this report for practical uses.

  13. Quantifying randomness in real networks

    Orsini, Chiara; Dankulov, Marija M.; Colomer-de-Simón, Pol; Jamakovic, Almerima; Mahadevan, Priya; Vahdat, Amin; Bassler, Kevin E.; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-10-01

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks--the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain--and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs.

  14. Solid-Phase Random Glycosylation

    Agoston, K.; Kröger, Lars; Dekany, Gyula;

    2009-01-01

    Two different approaches were employed to study solid phase random glycosylations to obtain oligosaccharide libraries. In approach I, Wang resin esters were attached to the acceptors structures. Following their glycosylation and resin cleavage, the peracetylated components of the oligosaccharide...

  15. Uses of randomness in computation

    Brent, Richard P

    2010-01-01

    Random number generators are widely used in practical algorithms. Examples include simulation, number theory (primality testing and integer factorization), fault tolerance, routing, cryptography, optimization by simulated annealing, and perfect hashing. Complexity theory usually considers the worst-case behaviour of deterministic algorithms, but it can also consider average-case behaviour if it is assumed that the input data is drawn randomly from a given distribution. Rabin popularised the idea of "probabilistic" algorithms, where randomness is incorporated into the algorithm instead of being assumed in the input data. Yao showed that there is a close connection between the complexity of probabilistic algorithms and the average-case complexity of deterministic algorithms. We give examples of the uses of randomness in computation, discuss the contributions of Rabin, Yao and others, and mention some open questions. This is the text of an invited talk presented at "Theory Day", University of NSW, Sydney, 22 Apr...

  16. Quantum-noise randomized ciphers

    We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by the salient feature responsible for their increased security. We describe a concrete system known as αη and show that it is equivalent to a random cipher in which the required randomization is affected by coherent-state quantum noise. We describe the currently known security features of αη and similar systems, including lower bounds on the unicity distances against ciphertext-only and known-plaintext attacks. We show how αη used in conjunction with any standard stream cipher such as the Advanced Encryption Standard provides an additional, qualitatively different layer of security from physical encryption against known-plaintext attacks on the key. We refute some claims in the literature that αη is equivalent to a nonrandom stream cipher

  17. A Randomized Central Limit Theorem

    Eliazar, Iddo; Klafter, Joseph

    2010-05-01

    The Central Limit Theorem (CLT), one of the most elemental pillars of Probability Theory and Statistical Physics, asserts that: the universal probability law of large aggregates of independent and identically distributed random summands with zero mean and finite variance, scaled by the square root of the aggregate-size (√{n}), is Gaussian. The scaling scheme of the CLT is deterministic and uniform - scaling all aggregate-summands by the common and deterministic factor √{n}. This Letter considers scaling schemes which are stochastic and non-uniform, and presents a "Randomized Central Limit Theorem" (RCLT): we establish a class of random scaling schemes which yields universal probability laws of large aggregates of independent and identically distributed random summands. The RCLT universal probability laws, in turn, are the one-sided and the symmetric Lévy laws.

  18. A Randomized Central Limit Theorem

    The Central Limit Theorem (CLT), one of the most elemental pillars of Probability Theory and Statistical Physics, asserts that: the universal probability law of large aggregates of independent and identically distributed random summands with zero mean and finite variance, scaled by the square root of the aggregate-size (√(n)), is Gaussian. The scaling scheme of the CLT is deterministic and uniform - scaling all aggregate-summands by the common and deterministic factor √(n). This Letter considers scaling schemes which are stochastic and non-uniform, and presents a 'Randomized Central Limit Theorem' (RCLT): we establish a class of random scaling schemes which yields universal probability laws of large aggregates of independent and identically distributed random summands. The RCLT universal probability laws, in turn, are the one-sided and the symmetric Levy laws.

  19. Random Matrices, Boundaries and Branes

    Niedner, Benjamin

    2016-01-01

    This thesis is devoted to the application of random matrix theory to the study of random surfaces, both discrete and continuous; special emphasis is placed on surface boundaries and the associated boundary conditions in this formalism. In particular, using a multi-matrix integral with permutation symmetry, we are able to calculate the partition function of the Potts model on a random planar lattice with various boundary conditions imposed. We proceed to investigate the correspondence between the critical points in the phase diagram of this model and two-dimensional Liouville theory coupled to conformal field theories with global $\\mathcal{W}$-symmetry. In this context, each boundary condition can be interpreted as the description of a brane in a family of bosonic string backgrounds. This investigation suggests that a spectrum of initially distinct boundary conditions of a given system may become degenerate when the latter is placed on a random surface of bounded genus, effectively leaving a smaller set of ind...

  20. Lowest Eigenvalues of Random Hamiltonians

    Shen, J J; Arima, A; Yoshinaga, N

    2008-01-01

    In this paper we present results of the lowest eigenvalues of random Hamiltonians for both fermion and boson systems. We show that an empirical formula of evaluating the lowest eigenvalues of random Hamiltonians in terms of energy centroids and widths of eigenvalues are applicable to many different systems (except for $d$ boson systems). We improve the accuracy of the formula by adding moments higher than two. We suggest another new formula to evaluate the lowest eigenvalues for random matrices with large dimensions (20-5000). These empirical formulas are shown to be applicable not only to the evaluation of the lowest energy but also to the evaluation of excited energies of systems under random two-body interactions.

  1. Randomness Relative to Cantor Expansions

    Calude, Cristian S.; Staiger, Ludwig; Svozil, Karl

    2003-01-01

    Imagine a sequence in which the first letter comes from a binary alphabet, the second letter can be chosen on an alphabet with 10 elements, the third letter can be chosen on an alphabet with 3 elements and so on. When such a sequence can be called random? In this paper we offer a solution to the above question using the approach to randomness proposed by Algorithmic Information Theory.

  2. Staggered chiral random matrix theory

    We present a random matrix theory for the staggered lattice QCD Dirac operator. The staggered random matrix theory is equivalent to the zero-momentum limit of the staggered chiral Lagrangian and includes all taste breaking terms at their leading order. This is an extension of previous work which only included some of the taste breaking terms. We will also present some results for the taste breaking contributions to the partition function and the Dirac eigenvalues.

  3. Registration of randomized clinical trials

    Østervig, R M; Sonne, A; Rasmussen, L S

    2015-01-01

    the proportion of correctly registered randomized controlled trials (RCTs) published in Acta from 2009 to 2014. METHODS: We manually searched all Acta issues from 2009 to 2014 for RCTs. Information about timing of data collection and registration in trial registries was extracted. We classified RCTs as correctly...... starting enrolment before 2010 to 63.2% after 2010 (24/38, P randomized controlled trials from Acta Anaesthesiologica Scandinavica were not adequately registered but the requirement of trial registration has...

  4. Enactive metaphoric approaches to randomness

    Díaz-Rojas, Daniela; Soto-Andrade, Jorge

    2015-01-01

    Our work aims at developing means to facilitating the access to stochastic thinking, especially for non-mathematically oriented learners. To this end, we draw on metaphoric and enactive approaches to the teaching and learning of randomness. More precisely, we report on a challenging didactical situation implemented in various classrooms, with students and prospective and practicing teachers, concerning problem posing and solving in the context of randomness that is approached through enactive...

  5. Optimal Contracts with Random Auditing

    Andrei Barbos

    2015-01-01

    In this paper we study an optimal contract problem under moral hazard in a principal-agent framework where contracts are implemented through random auditing. This monitoring instrument reveals the precise action taken by the agent with some nondegenerate probability r, and otherwise reveals no information. We characterize optimal contracts with random perfect monitoring under several information structures that allow for moral hazard and adverse selection. We evaluate the effect of the intens...

  6. Uses of randomness in computation

    Brent, Richard P.

    2010-01-01

    Random number generators are widely used in practical algorithms. Examples include simulation, number theory (primality testing and integer factorization), fault tolerance, routing, cryptography, optimization by simulated annealing, and perfect hashing. Complexity theory usually considers the worst-case behaviour of deterministic algorithms, but it can also consider average-case behaviour if it is assumed that the input data is drawn randomly from a given distribution. Rabin popularised the i...

  7. Random monitoring in financing relationships

    Sami, Hind

    2009-01-01

    This paper examines a financier's optimal monitoring intensity in a multi-period financing relationship.We identify conditions under which the financier should sometimes misidentify the quality of an entrepreneur. Such an imperfect evaluation technology affects action choices by bad entrepreneurs. We first characterize the optimal monitoring intensity and show that it is one in which the investor monitors entrepreneurs randomly. Random monitoring in the first stage of a relationship induces b...

  8. On Pfaffian Random Point Fields

    Kargin, V.

    2014-02-01

    We study Pfaffian random point fields by using the Moore-Dyson quaternion determinants. First, we give sufficient conditions that ensure that a self-dual quaternion kernel defines a valid random point field, and then we prove a CLT for Pfaffian point fields. The proofs are based on a new quaternion extension of the Cauchy-Binet determinantal identity. In addition, we derive the Fredholm determinantal formulas for the Pfaffian point fields which use the quaternion determinant.

  9. The weighted random graph model

    Garlaschelli, Diego

    2009-01-01

    We introduce the weighted random graph (WRG) model, which represents the weighted counterpart of the Erdos-Renyi random graph and provides fundamental insights into more complicated weighted networks. We find analytically that the WRG is characterized by a geometric weight distribution, a binomial degree distribution and a negative binomial strength distribution. We also characterize exactly the percolation phase transitions associated with edge removal and with the appearance of weighted sub...

  10. Pants decompositions of random surfaces

    Guth, Larry; Parlier, Hugo; Young, Robert

    2010-01-01

    Our goal is to show, in two different contexts, that "random" surfaces have large pants decompositions. First we show that there are hyperbolic surfaces of genus $g$ for which any pants decomposition requires curves of total length at least $g^{7/6 - \\epsilon}$. Moreover, we prove that this bound holds for most metrics in the moduli space of hyperbolic metrics equipped with the Weil-Petersson volume form. We then consider surfaces obtained by randomly gluing euclidean triangles (with unit sid...

  11. Random Construction of Riemann Surfaces

    Brooks, Robert; Makover, Eran

    2001-01-01

    We develop a new approach for the study of “typical” Riemann surfaces with high genus. The method that we use is the construction of random Riemann surfaces from oriented cubic graphs. This construction enables us to get a control over the global geometry properties of compact Riemann surfaces. We use the theory of random regular graphs to show that almost all such surfaces have large first eigenvalues and large Cheeger constants. Moreover a closer analysis of the probability space of oriente...

  12. A local limit theorem for random walks in random scenery and on randomly oriented lattices

    Castell, Fabienne; Pène, Françoise; Schapira, Bruno

    2010-01-01

    Random walks in random scenery are processes defined by $Z_n:=\\sum_{k=1}^n\\xi_{X_1+...+X_k}$, where $(X_k,k\\ge 1)$ and $(\\xi_y,y\\in\\mathbb Z)$ are two independent sequences of i.i.d. random variables. We assume here that their distributions belong to the normal domain of attraction of stable laws with index $\\alpha\\in (0,2]$ and $\\beta\\in (0,2]$ respectively. These processes were first studied by H. Kesten and F. Spitzer, who proved the convergence in distribution when $\\alpha\

  13. Random walk of passive tracers among randomly moving obstacles

    Gori, Matteo; Floriani, Elena; Nardecchia, Ilaria; Pettini, Marco

    2016-01-01

    Background: This study is mainly motivated by the need of understanding how the diffusion behaviour of a biomolecule (or even of a larger object) is affected by other moving macromolecules, organelles, and so on, inside a living cell, whence the possibility of understanding whether or not a randomly walking biomolecule is also subject to a long-range force field driving it to its target. Method: By means of the Continuous Time Random Walk (CTRW) technique the topic of random walk in random environment is here considered in the case of a passively diffusing particle in a crowded environment made of randomly moving and interacting obstacles. Results: The relevant physical quantity which is worked out is the diffusion cofficient of the passive tracer which is computed as a function of the average inter-obstacles distance. Coclusions: The results reported here suggest that if a biomolecule, let us call it a test molecule, moves towards its target in the presence of other independently interacting molecules, its m...

  14. Renewal theorems for random walks in random scenery

    Guillotin-Plantard, Nadine

    2011-01-01

    Random walks in random scenery are processes defined by $Z_n:=\\sum_{k=1}^n\\xi_{X_1+...+X_k}$, where $(X_k,k\\ge 1)$ and $(\\xi_y,y\\in\\mathbb Z)$ are two independent sequences of i.i.d. random variables. We suppose that the distributions of $X_1$ and $\\xi_0$ belong to the normal domain of attraction of strictly stable distributions with index $\\alpha\\in[1,2]$ and $\\beta\\in(0,2)$ respectively. We are interested in the asymptotic behaviour as $|a|$ goes to infinity of quantities of the form $\\sum_{n\\ge 1}{\\mathbb E}[h(Z_n-a)]$ (when $(Z_n)_n$ is transient) or $\\sum_{n\\ge 1}{\\mathbb E}[h(Z_n)-h(Z_n-a)]$ (when $(Z_n)_n$ is recurrent) where $h$ is some complex-valued function defined on $\\mathbb{R}$ or $\\mathbb{Z}$.

  15. The parabolic Anderson model random walk in random potential

    König, Wolfgang

    2016-01-01

    This is a comprehensive survey on the research on the parabolic Anderson model – the heat equation with random potential or the random walk in random potential – of the years 1990 – 2015. The investigation of this model requires a combination of tools from probability (large deviations, extreme-value theory, e.g.) and analysis (spectral theory for the Laplace operator with potential, variational analysis, e.g.). We explain the background, the applications, the questions and the connections with other models and formulate the most relevant results on the long-time behavior of the solution, like quenched and annealed asymptotics for the total mass, intermittency, confinement and concentration properties and mass flow. Furthermore, we explain the most successful proof methods and give a list of open research problems. Proofs are not detailed, but concisely outlined and commented; the formulations of some theorems are slightly simplified for better comprehension.

  16. Mondrian Forests: Efficient Online Random Forests

    Lakshminarayanan, Balaji; Roy, Daniel M.; Teh, Yee Whye

    2014-01-01

    Ensembles of randomized decision trees, usually referred to as random forests, are widely used for classification and regression tasks in machine learning and statistics. Random forests achieve competitive predictive performance and are computationally efficient to train and test, making them excellent candidates for real-world prediction tasks. The most popular random forest variants (such as Breiman's random forest and extremely randomized trees) operate on batches of training data. Online ...

  17. Exponential-family Random Network Models

    Fellows, I; Handcock, MS

    2012-01-01

    Random graphs, where the connections between nodes are considered random variables, have wide applicability in the social sciences. Exponential-family Random Graph Models (ERGM) have shown themselves to be a useful class of models for representing com- plex social phenomena. We generalize ERGM by also modeling nodal attributes as random variates, thus creating a random model of the full network, which we call Exponential-family Random Network Models (ERNM). We demonstrate how this framework a...

  18. Wave propagation and scattering in random media

    Ishimaru, Akira

    1978-01-01

    Wave Propagation and Scattering in Random Media, Volume 2, presents the fundamental formulations of wave propagation and scattering in random media in a unified and systematic manner. The topics covered in this book may be grouped into three categories: waves in random scatterers, waves in random continua, and rough surface scattering. Random scatterers are random distributions of many particles. Examples are rain, fog, smog, hail, ocean particles, red blood cells, polymers, and other particles in a state of Brownian motion. Random continua are the media whose characteristics vary randomly an

  19. Detecting Tampering in Random Graphs

    Pinsky, Ross G

    2012-01-01

    Let $\\mathcal{G}_n=(V_n,E_n)$ be a growing sequence of deterministic finite graphs, with $V_n$ denoting the vertices and $E_n$ denoting the edges. Consider the random graph $\\mathcal{G}_n(p_n)=(V_n, E_n(p_n))$ obtained by including any given edge with probability $p_n$, independent of other edges, and let $P_n^{p_n}$ denote the corresponding probability measure on $\\mathcal{G}_n$. Now tamper with the random graph in some regular way. For example, if $\\mathcal{G}_n$ is the complete graph on $n$ vertices, so that $\\mathcal{G}_n(p_n)$ is the Erdos-Renyi graph, then one might tamper with it by disconnecting all the edges of a randomly chosen vertex, or by adding all the edges of a randomly chosen Hamiltonian path from $\\mathcal{G}_n$, or by adding all the edges of a randomly chosen clique of order $k_n$ from $\\mathcal{G}_n$. Denote the resulting induced measure on $\\mathcal{G}_n$ by $P_n^{p_n,\\text{tamper}}$. The tampering is called \\it detectable\\rm\\ if $\\lim_{n\\to\\infty}||P_n^{p_n,\\text{tamper}}-P_n^{p_n}||_{\\t...

  20. Advances in randomized parallel computing

    Rajasekaran, Sanguthevar

    1999-01-01

    The technique of randomization has been employed to solve numerous prob­ lems of computing both sequentially and in parallel. Examples of randomized algorithms that are asymptotically better than their deterministic counterparts in solving various fundamental problems abound. Randomized algorithms have the advantages of simplicity and better performance both in theory and often in practice. This book is a collection of articles written by renowned experts in the area of randomized parallel computing. A brief introduction to randomized algorithms In the aflalysis of algorithms, at least three different measures of performance can be used: the best case, the worst case, and the average case. Often, the average case run time of an algorithm is much smaller than the worst case. 2 For instance, the worst case run time of Hoare's quicksort is O(n ), whereas its average case run time is only O( n log n). The average case analysis is conducted with an assumption on the input space. The assumption made to arrive at t...

  1. Cover times of random searches

    Chupeau, Marie; Bénichou, Olivier; Voituriez, Raphaël

    2015-10-01

    How long must one undertake a random search to visit all sites of a given domain? This time, known as the cover time, is a key observable to quantify the efficiency of exhaustive searches, which require a complete exploration of an area and not only the discovery of a single target. Examples range from immune-system cells chasing pathogens to animals harvesting resources, from robotic exploration for cleaning or demining to the task of improving search algorithms. Despite its broad relevance, the cover time has remained elusive and so far explicit results have been scarce and mostly limited to regular random walks. Here we determine the full distribution of the cover time for a broad range of random search processes, including Lévy strategies, intermittent strategies, persistent random walks and random walks on complex networks, and reveal its universal features. We show that for all these examples the mean cover time can be minimized, and that the corresponding optimal strategies also minimize the mean search time for a single target, unambiguously pointing towards their robustness.

  2. RANDOM VARIABLE WITH FUZZY PROBABILITY

    吕恩琳; 钟佑明

    2003-01-01

    Mathematic description about the second kind fuzzy random variable namely the random variable with crisp event-fuzzy probability was studied. Based on the interval probability and using the fuzzy resolution theorem, the feasible condition about a probability fuzzy number set was given, go a step further the definition arid characters of random variable with fuzzy probability ( RVFP ) and the fuzzy distribution function and fuzzy probability distribution sequence of the RVFP were put forward. The fuzzy probability resolution theorem with the closing operation of fuzzy probability was given and proved. The definition and characters of mathematical expectation and variance of the RVFP were studied also. All mathematic description about the RVFP has the closing operation for fuzzy probability, as a result, the foundation of perfecting fuzzy probability operation method is laid.

  3. Propagation in multiscale random media

    Balk, Alexander M.

    2003-10-01

    Many studies consider media with microstructure, which has variations on some microscale, while the macroproperties are under investigation. Sometimes the medium has several microscales, all of them being much smaller than the macroscale. Sometimes the variations on the macroscale are also included, which are taken into account by some procedures, like WKB or geometric optics. What if the medium has variations on all scales from microscale to macroscale? This situation occurs in several practical problems. The talk is about such situations, in particular, passive tracer in a random velocity field, wave propagation in a random medium, Schrödinger equation with random potential. To treat such problems we have developed the statistical near-identity transformation. We find anomalous attenuation of the pulse propagating in a multiscale medium.

  4. Propagation in multiscale random media

    Many studies consider media with microstructure, which has variations on some microscale, while the macroproperties are under investigation. Sometimes the medium has several microscales, all of them being much smaller than the macroscale. Sometimes the variations on the macroscale are also included, which are taken into account by some procedures, like WKB or geometric optics. What if the medium has variations on all scales from microscale to macroscale? This situation occurs in several practical problems. The talk is about such situations, in particular, passive tracer in a random velocity field, wave propagation in a random medium, Schroedinger equation with random potential. To treat such problems we have developed the statistical near-identity transformation. We find anomalous attenuation of the pulse propagating in a multiscale medium

  5. Propagation in multiscale random media

    Balk, A.M

    2003-10-01

    Many studies consider media with microstructure, which has variations on some microscale, while the macroproperties are under investigation. Sometimes the medium has several microscales, all of them being much smaller than the macroscale. Sometimes the variations on the macroscale are also included, which are taken into account by some procedures, like WKB or geometric optics. What if the medium has variations on all scales from microscale to macroscale? This situation occurs in several practical problems. The talk is about such situations, in particular, passive tracer in a random velocity field, wave propagation in a random medium, Schroedinger equation with random potential. To treat such problems we have developed the statistical near-identity transformation. We find anomalous attenuation of the pulse propagating in a multiscale medium.

  6. Surrogates with random Fourier Phases

    Raeth, Christoph

    2008-01-01

    The method of surrogates is widely used in the field of nonlinear data analysis for testing for weak nonlinearities. The two most commonly used algorithms for generating surrogates are the amplitude adjusted Fourier transform (AAFT) and the iterated amplitude adjusted Fourier transfom (IAAFT) algorithm. Both the AAFT and IAAFT algorithm conserve the amplitude distribution in real space and reproduce the power spectrum (PS) of the original data set very accurately. The basic assumption in both algorithms is that higher-order correlations can be wiped out using a Fourier phase randomization procedure. In both cases, however, the randomness of the Fourier phases is only imposed before the (first) Fourier back tranformation. Until now, it has not been studied how the subsequent remapping and iteration steps may affect the randomness of the phases. Using the Lorenz system as an example, we show that both algorithms may create surrogate realizations containing Fourier phase correlations. We present two new iterativ...

  7. Random Decrement Based FRF Estimation

    Brincker, Rune; Asmussen, J. C.

    The problem of estimating frequency response functions and extracting modal parameters is the topic of this paper. A new method based on the Random Decrement technique combined with Fourier transformation and the traditional pure Fourier transformation based approach is compared with regard to...... speed and quality. The basis of the new method is the Fourier transformation of the Random Decrement functions which can be used to estimate the frequency response functions. The investigations are based on load and response measurements of a laboratory model of a 3 span bridge. By applying both methods...... to these measurements the estimation time of the frequency response functions can be compared. The modal parameters estimated by the methods are compared. It is expected that the Random Decrement technique is faster than the traditional method based on pure Fourier Transformations. This is due to the...

  8. Random Decrement Based FRF Estimation

    Brincker, Rune; Asmussen, J. C.

    1997-01-01

    The problem of estimating frequency response functions and extracting modal parameters is the topic of this paper. A new method based on the Random Decrement technique combined with Fourier transformation and the traditional pure Fourier transformation based approach is compared with regard to...... speed and quality. The basis of the new method is the Fourier transformation of the Random Decrement functions which can be used to estimate the frequency response functions. The investigations are based on load and response measurements of a laboratory model of a 3 span bridge. By applying both methods...... to these measurements the estimation time of the frequency response functions can be compared. The modal parameters estimated by the methods are compared. It is expected that the Random Decrement technique is faster than the traditional method based on pure Fourier Transformations. This is due to the...

  9. Fatigue Reliability under Random Loads

    Talreja, R.

    1979-01-01

    We consider the problem of estimating the probability of survival (non-failure) and the probability of safe operation (strength greater than a limiting value) of structures subjected to random loads. These probabilities are formulated in terms of the probability distributions of the loads and the...... material strength. For the material strength, the Weibull distribution is assumed, the parameters of which are estimated by a statistical analysis of the experimental tensile strength of steel specimens subjected to different periods of random loads. The statistical analysis shows that, with the...... application of random loads, the initial homogeneous distribution of strength changes to a two-component distribution, reflecting the two-stage fatigue damage. In the crack initiation stage, the strength increases initially and then decreases, while an abrupt decrease of strength is seen in the crack...

  10. How random are complex networks

    Orsini, Chiara; Jamakovic, Almerima; Mahadevan, Priya; Colomer-de-Simón, Pol; Vahdat, Amin; Bassler, Kevin E; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-01-01

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the $dk$-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks---the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain---and find that many important local and global structural properties of these networks are closely reproduced by $dk$-random graphs whose degree distributions, degree correlations, and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness.

  11. On the local time of random processes in random scenery

    Castell, Fabienne; Pène, Françoise; Schapira, Bruno

    2012-01-01

    Random walks in random scenery are processes defined by $Z_n:=\\sum_{k=1}^n\\xi_{X_1+...+X_k}$, where basically $(X_k,k\\ge 1)$ and $(\\xi_y,y\\in\\mathbb Z)$ are two independent sequences of i.i.d. random variables. We assume here that $X_1$ is $\\ZZ$-valued, centered and with finite moments of all orders. We also assume that $\\xi_0$ is $\\ZZ$-valued, centered and square integrable. In this case H. Kesten and F. Spitzer proved that $(n^{-3/4}Z_{[nt]},t\\ge 0)$ converges in distribution as $n\\to \\infty$ toward some self-similar process $(\\Delta_t,t\\ge 0)$ called Brownian motion in random scenery. In a previous paper, we established that ${\\mathbb P}(Z_n=0)$ behaves asymptotically like a constant times $n^{-3/4}$, as $n\\to \\infty$. We extend here this local limit theorem: we give a precise asymptotic result for the probability for $Z$ to return to zero simultaneously at several times. As a byproduct of our computations, we show that $\\Delta$ admits a bi-continuous version of its local time process which is locally H\\"o...

  12. A Randomized Experiment Comparing Random and Cutoff-Based Assignment

    Shadish, William R.; Galindo, Rodolfo; Wong, Vivian C.; Steiner, Peter M.; Cook, Thomas D.

    2011-01-01

    In this article, we review past studies comparing randomized experiments to regression discontinuity designs, mostly finding similar results, but with significant exceptions. The latter might be due to potential confounds of study characteristics with assignment method or with failure to estimate the same parameter over methods. In this study, we…

  13. Relatively Random: Context Effects on Perceived Randomness and Predicted Outcomes

    Matthews, William J.

    2013-01-01

    This article concerns the effect of context on people's judgments about sequences of chance outcomes. In Experiment 1, participants judged whether sequences were produced by random, mechanical processes (such as a roulette wheel) or skilled human action (such as basketball shots). Sequences with lower alternation rates were judged more likely to…

  14. Bose condensation in (random traps

    V.A. Zagrebnov

    2009-01-01

    Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.

  15. Neutron transport in random media

    The survey reviews the methods available in the literature which allow a discussion of corium recriticality after a severe accident and a characterization of the corium. It appears that to date no one has considered the eigenvalue problem, though for the source problem several approaches have been proposed. The mathematical formulation of a random medium may be approached in different ways. Based on the review of the literature, we can draw three basic conclusions. The problem of static, random perturbations has been solved. The static case is tractable by the Monte Carlo method. There is a specific time dependent case for which the average flux is given as a series expansion

  16. Random Walks Estimate Land Value

    Blanchard, Ph

    2010-01-01

    Expected urban population doubling calls for a compelling theory of the city. Random walks and diffusions defined on spatial city graphs spot hidden areas of geographical isolation in the urban landscape going downhill. First--passage time to a place correlates with assessed value of land in that. The method accounting the average number of random turns at junctions on the way to reach any particular place in the city from various starting points could be used to identify isolated neighborhoods in big cities with a complex web of roads, walkways and public transport systems.

  17. Truncations of random unitary matrices

    Zyczkowski, K; Zyczkowski, Karol; Sommers, Hans-Juergen

    1999-01-01

    We analyze properties of non-hermitian matrices of size M constructed as square submatrices of unitary (orthogonal) random matrices of size N>M, distributed according to the Haar measure. In this way we define ensembles of random matrices and study the statistical properties of the spectrum located inside the unit circle. In the limit of large matrices, this ensemble is characterized by the ratio M/N. For the truncated CUE we derive analytically the joint density of eigenvalues from which easily all correlation functions are obtained. For N-M fixed and N--> infinity the universal resonance-width distribution with N-M open channels is recovered.

  18. Synchronizability of random rectangular graphs

    Estrada, Ernesto, E-mail: ernesto.estrada@strath.ac.uk; Chen, Guanrong [Department of Mathematics & Statistics, University of Strathclyde, 26 Richmond Street, Glasgow G1 1XQ, United Kingdom and Department of Electronic Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong)

    2015-08-15

    Random rectangular graphs (RRGs) represent a generalization of the random geometric graphs in which the nodes are embedded into hyperrectangles instead of on hypercubes. The synchronizability of RRG model is studied. Both upper and lower bounds of the eigenratio of the network Laplacian matrix are determined analytically. It is proven that as the rectangular network is more elongated, the network becomes harder to synchronize. The synchronization processing behavior of a RRG network of chaotic Lorenz system nodes is numerically investigated, showing complete consistence with the theoretical results.

  19. Random sequential packing of cubes

    Sikiric, Mathieu Dutour

    2011-01-01

    In this volume very simplified models are introduced to understand the random sequential packing models mathematically. The 1-dimensional model is sometimes called the Parking Problem, which is known by the pioneering works by Flory (1939), Renyi (1958), Dvoretzky and Robbins (1962). To obtain a 1-dimensional packing density, distribution of the minimum of gaps, etc., the classical analysis has to be studied. The packing density of the general multi-dimensional random sequential packing of cubes (hypercubes) makes a well-known unsolved problem. The experimental analysis is usually applied to t

  20. Synchronizability of random rectangular graphs

    Random rectangular graphs (RRGs) represent a generalization of the random geometric graphs in which the nodes are embedded into hyperrectangles instead of on hypercubes. The synchronizability of RRG model is studied. Both upper and lower bounds of the eigenratio of the network Laplacian matrix are determined analytically. It is proven that as the rectangular network is more elongated, the network becomes harder to synchronize. The synchronization processing behavior of a RRG network of chaotic Lorenz system nodes is numerically investigated, showing complete consistence with the theoretical results

  1. Gibbs states on random configurations

    Gibbs states of a spin system with the single-spin space S=Rm and unbounded pair interactions are studied. The spins are attached to the points of a realization γ of a random point process in Rn. Under certain conditions on the model parameters we prove that, for almost all γ, the set G(Sγ) of all Gibbs states is nonempty and its elements have support properties, explicitly described in the paper. We also show the existence of measurable selections γ↦νγ∈G(Sγ) (random Gibbs measures) and derive the corresponding averaged moment estimates

  2. Effect of an office worksite-based yoga program on heart rate variability: A randomized controlled trial

    Chang Dennis

    2011-07-01

    Full Text Available Abstract Background Chronic work-related stress is a significant and independent risk factor for cardiovascular and metabolic diseases and associated mortality, particularly when compounded by a sedentary work environment. Heart rate variability (HRV provides an estimate of parasympathetic and sympathetic autonomic control, and can serve as a marker of physiological stress. Hatha yoga is a physically demanding practice that can help to reduce stress; however, time constraints incurred by work and family life may limit participation. The purpose of the present study is to determine if a 10-week, worksite-based yoga program delivered during lunch hour can improve resting HRV and related physical and psychological parameters in sedentary office workers. Methods and design This is a parallel-arm RCT that will compare the outcomes of participants assigned to the experimental treatment group (yoga to those assigned to a no-treatment control group. Participants randomized to the experimental condition will engage in a 10-week yoga program delivered at their place of work. The yoga sessions will be group-based, prescribed three times per week during lunch hour, and will be led by an experienced yoga instructor. The program will involve teaching beginner students safely and progressively over 10 weeks a yoga sequence that incorporates asanas (poses and postures, vinyasa (exercises, pranayama (breathing control and meditation. The primary outcome of this study is the high frequency (HF spectral power component of HRV (measured in absolute units; i.e. ms2, a measure of parasympathetic autonomic control. Secondary outcomes include additional frequency and time domains of HRV, and measures of physical functioning and psychological health status. Measures will be collected prior to and following the intervention period, and at 6 months follow-up to determine the effect of intervention withdrawal. Discussion This study will determine the effect of worksite

  3. A Mixed Effects Randomized Item Response Model

    Fox, J.-P.; Wyrick, Cheryl

    2008-01-01

    The randomized response technique ensures that individual item responses, denoted as true item responses, are randomized before observing them and so-called randomized item responses are observed. A relationship is specified between randomized item response data and true item response data. True item response data are modeled with a (non)linear…

  4. Random fixed point theorems on product spaces

    Ismat Beg; Naseer Shahzad

    1993-01-01

    The existence of random fixed point of a locally contractive random operator in first variable on product spaces is proved. The concept “continuous random height-selection” is discussed. Some random fixed point theorems for nonexpansive self and nonself maps are also obtained in product spaces.

  5. Randomized clinical trials in HEPATOLOGY

    Kjaergard, L L; Nikolova, D; Gluud, C

    1999-01-01

    Evidence shows that the quality of randomized clinical trials (RCTs) affects estimates of intervention efficacy, which is significantly exaggerated in low-quality trials. The present study examines the quality of all 235 RCTs published in HEPATOLOGY from the initiation in 1981 through August 1998...

  6. Random packing of digitized particles

    Korte, de A.C.J.; Brouwers, H.J.H.

    2012-01-01

    The random packing of regularly and irregularly shaped particles has been studied extensively. Within this paper, packing is studied from the perspective of digitized particles. These digitized particles are developed for and used in cellular automata systems, which are employed for the simple mathe

  7. Models of random graph hierarchies

    Paluch, Robert; Holyst, Janusz

    2015-01-01

    We introduce two models of inclusion hierarchies: Random Graph Hierarchy (RGH) and Limited Random Graph Hierarchy (LRGH). In both models a set of nodes at a given hierarchy level is connected randomly, as in the Erd\\H{o}s-R\\'{e}nyi random graph, with a fixed average degree equal to a system parameter $c$. Clusters of the resulting network are treated as nodes at the next hierarchy level and they are connected again at this level and so on, until the process cannot continue. In the RGH model we use all clusters, including those of size $1$, when building the next hierarchy level, while in the LRGH model clusters of size $1$ stop participating in further steps. We find that in both models the number of nodes at a given hierarchy level $h$ decreases approximately exponentially with $h$. The height of the hierarchy $H$, i.e. the number of all hierarchy levels, increases logarithmically with the system size $N$, i.e. with the number of nodes at the first level. The height $H$ decreases monotonically with the conne...

  8. Models of random graph hierarchies

    Paluch, Robert; Suchecki, Krzysztof; Hołyst, Janusz A.

    2015-10-01

    We introduce two models of inclusion hierarchies: random graph hierarchy (RGH) and limited random graph hierarchy (LRGH). In both models a set of nodes at a given hierarchy level is connected randomly, as in the Erdős-Rényi random graph, with a fixed average degree equal to a system parameter c. Clusters of the resulting network are treated as nodes at the next hierarchy level and they are connected again at this level and so on, until the process cannot continue. In the RGH model we use all clusters, including those of size 1, when building the next hierarchy level, while in the LRGH model clusters of size 1 stop participating in further steps. We find that in both models the number of nodes at a given hierarchy level h decreases approximately exponentially with h. The height of the hierarchy H, i.e. the number of all hierarchy levels, increases logarithmically with the system size N, i.e. with the number of nodes at the first level. The height H decreases monotonically with the connectivity parameter c in the RGH model and it reaches a maximum for a certain c max in the LRGH model. The distribution of separate cluster sizes in the LRGH model is a power law with an exponent about - 1.25. The above results follow from approximate analytical calculations and have been confirmed by numerical simulations.

  9. Fatigue Reliability under Random Loads

    Talreja, R.

    1979-01-01

    We consider the problem of estimating the probability of survival (non-failure) and the probability of safe operation (strength greater than a limiting value) of structures subjected to random loads. These probabilities are formulated in terms of the probability distributions of the loads and the...... propagation stage. The consequences of this behaviour on the fatigue reliability are discussed....

  10. Beyond the random phase approximation

    Olsen, Thomas; Thygesen, Kristian S.

    2013-01-01

    We assess the performance of a recently proposed renormalized adiabatic local density approximation (rALDA) for ab initio calculations of electronic correlation energies in solids and molecules. The method is an extension of the random phase approximation (RPA) derived from time-dependent density...