WorldWideScience

Sample records for rhythm irregularity assessed

  1. Circadian rhythms in cognitive performance: implications for neuropsychological assessment

    Directory of Open Access Journals (Sweden)

    Valdez P

    2012-12-01

    Full Text Available Pablo Valdez, Candelaria Ramírez, Aída GarcíaLaboratory of Psychophysiology, School of Psychology, University of Nuevo León, Monterrey, Nuevo León, MéxicoAbstract: Circadian variations have been found in human performance, including the efficiency to execute many tasks, such as sensory, motor, reaction time, time estimation, memory, verbal, arithmetic calculations, and simulated driving tasks. Performance increases during the day and decreases during the night. Circadian rhythms have been found in three basic neuropsychological processes (attention, working memory, and executive functions, which may explain oscillations in the performance of many tasks. The time course of circadian rhythms in cognitive performance may be modified significantly in patients with brain disorders, due to chronotype, age, alterations of the circadian rhythm, sleep deprivation, type of disorder, and medication. This review analyzes the recent results on circadian rhythms in cognitive performance, as well as the implications of these rhythms for the neuropsychological assessment of patients with brain disorders such as traumatic head injury, stroke, dementia, developmental disorders, and psychiatric disorders.Keywords: human circadian rhythms, cognitive performance, neuropsychological assessment, attention, working memory, executive functions

  2. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015

    Science.gov (United States)

    Auger, R. Robert; Burgess, Helen J.; Emens, Jonathan S.; Deriy, Ludmila V.; Thomas, Sherene M.; Sharkey, Katherine M.

    2015-01-01

    A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed. Citation: Auger RR, Burgess HJ, Emens JS, Deriy LV, Thomas SM, Sharkey KM. Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disorders: advanced sleep-wake phase disorder (ASWPD), delayed sleep-wake phase disorder (DSWPD), non-24-hour sleep-wake rhythm disorder (N24SWD), and irregular sleep-wake rhythm disorder (ISWRD). An update for 2015. J Clin Sleep Med 2015;11(10):1199–1236. PMID:26414986

  3. Assessing the Adaptability to Irregular Rest-Work Rhythms in Military Personnel

    Science.gov (United States)

    2000-03-01

    Aeronautica Militare Italiana, CSV Reparto Medicina Aerospaziale Pratica di Mare, 00040 Pomezia (Roma) Italy 2 Dipartimento di Psicologia - Universitd...characteristics to adapt to increased work errors and impaired social work at unusual hours. and family relationship. In addition, there is an increased mortality...DUTY: a brief questionnaire on critical evaluation. Journal of Personality the sleep-wake cycle and vigilance filled in and Social Psychology. 58: 844

  4. Ecological assessment of seasonal bioclimatic and production rhythms in agrosystems of the Republic of Armenia

    Directory of Open Access Journals (Sweden)

    Arsen Grigoryan

    2017-06-01

    Full Text Available In the article the time features of occurrence of bioclimatic and industrial rhythms according to altitudinal belts are analyzed, a nomogram is composed and spatial and time patterns of rhythms are revealed, the ways of the rational use of seasonal rhythms and greening agrosystems of the Republic of Armenia (RA are shown. The paper summarizes 80–100-year summer monitoring data on onset timing of the main seasonal bioclimatic rhythms of animate and inanimate nature in the RA. The definition of bioclimatic rhythms is given. The importance of studies of seasonal rhythms of nature and society, especially in the non-tropical zones of the Earth is shown. Besides, the special importance of bioclimatic seasonal rhythms' study in order to optimize agro-zootechnical activities and to green agricultural systems is emphasized. Continuous chain of natural rhythms leads to the formation of adequate seasonal rhythms in the production activities of all sectors of the economy, ensuring the functioning of the biosphere and society. The regularities of the timing of seasonal bioclimatic rhythms' onset by the vertical zones in Armenia taking into account the atmospheric moisture of regions is set, vertical gradients are calculated and a nomogram allowing to develop calendars of seasonal works being carried out in certain regions is drawn.

  5. Sex Differences in the Relationship Between Depressive Symptoms and Actigraphic Assessments of Sleep and Rest-Activity Rhythms in a Population-Based Sample.

    Science.gov (United States)

    White, Kaitlin Hanley; Rumble, Meredith E; Benca, Ruth M

    2017-05-01

    Depression is often associated with disruptions in sleep and circadian rhythms. We aimed to confirm these relationships via actigraphic assessment in a large, population-based sample and test whether sex moderates these relationships. A total of 418 participants (age = 35-85 years, mean [standard deviation] = 57.04 [11.47]) completed questionnaires and 1 week of actigraphy, used to calculate sleep and rest-activity statistics including mesor (mean activity level), amplitude (height of rhythm), and acrophase (time of day that rhythm peaks). Depressive symptoms, assessed via Center for Epidemiologic Studies Depression Scale, were associated with disrupted sleep and rest-activity rhythms. Furthermore, men demonstrated longer sleep onset latency (SOL, B = -13.28, p continuity and rest-activity rhythms in this population-based sample; however, these relationships differed by sex. Women with greater depressive symptoms exhibited difficulty with sleep continuity, whereas men with greater depressive symptoms demonstrated disruption throughout the 24-hour rhythm.

  6. Multidimensional assessment of strongly irregular voices such as in substitution voicing and spasmodic dysphonia: a compilation of own research.

    Science.gov (United States)

    Moerman, Mieke; Martens, Jean-Pierre; Dejonckere, Philippe

    2015-04-01

    This article is a compilation of own research performed during the European COoperation in Science and Technology (COST) action 2103: 'Advance Voice Function Assessment', an initiative of voice and speech processing teams consisting of physicists, engineers, and clinicians. This manuscript concerns analyzing largely irregular voicing types, namely substitution voicing (SV) and adductor spasmodic dysphonia (AdSD). A specific perceptual rating scale (IINFVo) was developed, and the Auditory Model Based Pitch Extractor (AMPEX), a piece of software that automatically analyses running speech and generates pitch values in background noise, was applied. The IINFVo perceptual rating scale has been shown to be useful in evaluating SV. The analysis of strongly irregular voices stimulated a modification of the European Laryngological Society's assessment protocol which was originally designed for the common types of (less severe) dysphonia. Acoustic analysis with AMPEX demonstrates that the most informative features are, for SV, the voicing-related acoustic features and, for AdSD, the perturbation measures. Poor correlations between self-assessment and acoustic and perceptual dimensions in the assessment of highly irregular voices argue for a multidimensional approach.

  7. Design and validation of a three-instrument toolkit for the assessment of competence in electrocardiogram rhythm recognition.

    Science.gov (United States)

    Hernández-Padilla, José M; Granero-Molina, José; Márquez-Hernández, Verónica V; Suthers, Fiona; López-Entrambasaguas, Olga M; Fernández-Sola, Cayetano

    2017-06-01

    Rapid and accurate interpretation of cardiac arrhythmias by nurses has been linked with safe practice and positive patient outcomes. Although training in electrocardiogram rhythm recognition is part of most undergraduate nursing programmes, research continues to suggest that nurses and nursing students lack competence in recognising cardiac rhythms. In order to promote patient safety, nursing educators must develop valid and reliable assessment tools that allow the rigorous assessment of this competence before nursing students are allowed to practise without supervision. The aim of this study was to develop and psychometrically evaluate a toolkit to holistically assess competence in electrocardiogram rhythm recognition. Following a convenience sampling technique, 293 nursing students from a nursing faculty in a Spanish university were recruited for the study. The following three instruments were developed and psychometrically tested: an electrocardiogram knowledge assessment tool (ECG-KAT), an electrocardiogram skills assessment tool (ECG-SAT) and an electrocardiogram self-efficacy assessment tool (ECG-SES). Reliability and validity (content, criterion and construct) of these tools were meticulously examined. A high Cronbach's alpha coefficient demonstrated the excellent reliability of the instruments (ECG-KAT=0.89; ECG-SAT=0.93; ECG-SES=0.98). An excellent context validity index (scales' average content validity index>0.94) and very good criterion validity were evidenced for all the tools. Regarding construct validity, principal component analysis revealed that all items comprising the instruments contributed to measure knowledge, skills or self-efficacy in electrocardiogram rhythm recognition. Moreover, known-groups analysis showed the tools' ability to detect expected differences in competence between groups with different training experiences. The three-instrument toolkit developed showed excellent psychometric properties for measuring competence in

  8. The Biological Rhythms Interview of Assessment in Neuropsychiatry in patients with bipolar disorder: correlation with affective temperaments and schizotypy

    Directory of Open Access Journals (Sweden)

    Ewa Dopierala

    Full Text Available Objective: To assess the relationship of biological rhythms, evaluated by the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN, with affective temperaments and schizotypy. Methods: The BRIAN assessment, along with the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A and the Oxford-Liverpool Inventory for Feelings and Experiences (O-LIFE, was administered to 54 patients with remitted bipolar disorder (BD and 54 healthy control (HC subjects. Results: The TEMPS-A cyclothymic temperament correlated positively and the hyperthymic temperament correlated negatively with BRIAN scores in both the BD and HC groups, although the correlation was stronger in BD subjects. Depressive temperament was associated with BRIAN scores in BD but not in HC; conversely, the irritable temperament was associated with BRIAN scores in HC, but not in BD. Several positive correlations between BRIAN scores and the schizotypal dimensions of the O-LIFE were observed in both BD and HC subjects, especially with cognitive disorganization and less so with unusual experiences and impulsive nonconformity. A correlation with introversion/anhedonia was found only in BD subjects. Conclusion: Cyclothymic and depressive temperaments predispose to disturbances of biological rhythms in BD, while a hyperthymic temperament can be protective. Similar predispositions were also found for all schizotypal dimensions, mostly for cognitive disorganization.

  9. Circadian Rhythms

    Indian Academy of Sciences (India)

    IAS Admin

    thus appear to be simple responses of living beings to cyclic presence/absence of ... For example, during leaf movement rhythms, leaves alternate between open and closed states .... gist of his time, in an elegant experiment (Box 2) to study the navigational .... diurnal rhythms as true biological timekeepers, a question which.

  10. Circadian Rhythms

    Indian Academy of Sciences (India)

    IAS Admin

    and clocks driving such rhythms have been studied for a long time now, our ... passage of time using near 24 h oscillation as a reference process, and (iii) Output .... Bünning's work on circadian rhythms across model systems ranging from ..... E Bünning, The Physiological Clock, Revised 3rd Edition, The English. Universities ...

  11. Out-of-round railway wheels—assessment of wheel tread irregularities in train traffic

    Science.gov (United States)

    Johansson, Anders

    2006-06-01

    Results from an extensive wheel measurement campaign performed in Sweden are given and discussed. Out-of-roundness (OOR), transverse profile and surface hardness of 99 wheels on passenger trains (X2 and intercity), freight trains, commuter trains (Regina) and underground trains (C20) were measured. Both tread and disc braked wheels were investigated. The selected wheels had travelled a distance of more than 100000 km, and the measurements were conducted when the train wagons/coaches had been taken out of traffic for maintenance, most of them due to reasons other than wheel OOR. Mechanical contact measurement methods were used. The highest roughness levels (higher than 20 dB re 1 μm for some wheels) were found on powered high-speed (X2) train wheels. The previously known polygonalization of C20 underground wheels is quantified. It is also verified that an initial irregularity is formed due to the clamping in a three-jaw chuck during profiling of new C20 wheels. Magnitudes and wavelength contents of measured wheel roughness are compared with corresponding measurements of rail roughness.

  12. Circadian Rhythms

    Indian Academy of Sciences (India)

    IAS Admin

    nature of the system underlying such rhythms and inspired one of the ... behaviours and physiological processes were discovered in a wide range of animals. ... is thought to coordinate internal physiology, and thereby confer benefits to living ...

  13. ‘Ragged Time’ in Intra-panel Comics Rhythms

    Directory of Open Access Journals (Sweden)

    Corry Shores

    2016-07-01

    Full Text Available A phenomenological method of comics analysis can be useful when we need to uncover the structural features of the comics experience itself. One fruitful application would be in the study of irregular intra-panel rhythms, where the temporalized divisions are not visibly indicated but rather are only experienced. By means of Gilles Deleuze’s notion of rhythmic repetition and his elaboration of it through Olivier Messiaen’s theory of ‘kinetic’ rhythm, we will formulate a conception of visual rhythm as being based on metrical irregularity. We further explicate this concept of irregular rhythm by drawing upon the notion of ‘ragged time’ in the early jazz musical form, ragtime. We finally test its usefulness by examining how the ‘jazzy’ rhythms of Cubist-styled panels by Art Spiegelman and Mary Fleener generate an experience of ragged time.

  14. Circadian Rhythms

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 11. Circadian Rhythms ... M Vaze1 Vijay Kumar Sharma1. Chronobiology Laboratory Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, PO Box 6436, Bangalore 560 064, India.

  15. Circadian Rhythms

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 2. Circadian Rhythms: Why do ... Nikhil Vijay Kumar Sharma1. Chronobiology Laboratory Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, PO Box 6436, Bangalore 560 064, India.

  16. Circadian Rhythms

    Indian Academy of Sciences (India)

    IAS Admin

    Early studies on circadian rhythms focussed on unravelling the fundamental .... careful analysis revealed that deaths of most arrhythmic indi- viduals were due to .... is no more a sci-fi movie script and is achievable through a technique called ...

  17. Irregular Applications: Architectures & Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Feo, John T.; Villa, Oreste; Tumeo, Antonino; Secchi, Simone

    2012-02-06

    Irregular applications are characterized by irregular data structures, control and communication patterns. Novel irregular high performance applications which deal with large data sets and require have recently appeared. Unfortunately, current high performance systems and software infrastructures executes irregular algorithms poorly. Only coordinated efforts by end user, area specialists and computer scientists that consider both the architecture and the software stack may be able to provide solutions to the challenges of modern irregular applications.

  18. Naturally occurring circadian rhythm and sleep duration are related to executive functions in early adulthood.

    Science.gov (United States)

    Kuula, Liisa; Pesonen, Anu-Katriina; Heinonen, Kati; Kajantie, Eero; Eriksson, Johan Gunnar; Andersson, Sture; Lano, Aulikki; Lahti, Jari; Wolke, Dieter; Räikkönen, Katri

    2018-02-01

    Experimental sleep deprivation studies suggest that insufficient sleep and circadian misalignment associates with poorer executive function. It is not known whether this association translates to naturally occurring sleep patterns. A total of 512 of full-term-born members of the Arvo Ylppö Longitudinal Study [mean age = 25.3, standard deviation (SD) = 0.65] (44.3% men) wore actigraphs to define sleep duration, its irregularity and circadian rhythm (sleep mid-point) during a 1-week period (mean 6.9 nights, SD = 1.7). Performance-based executive function was assessed with the Trail-Making Test, Conners' Continuous Performance Test and Stroop. The self-rated adult version of Behavior Rating Inventory of Executive Function was used to assess trait-like executive function. We found that performance-based and self-reported trait-like executive function correlated only modestly (all correlations ≤0.17). Shorter sleep duration associated with more commission errors. Later circadian rhythm associated with poorer trait-like executive function, as indicated by the Brief Metacognitive Index and the Behavior Regulation Index. Those belonging to the group with the most irregular sleep duration performed slower than others in the Trail-Making Test Part A. All associations were adjusted for sex, age, socioeconomic status and body mass index. In conclusion, naturally occurring insufficient sleep and later circadian rhythm showed modest associations with poorer executive function. Shorter habitual sleep duration was associated with lower scores of performance-based tests of executive function, and later circadian rhythm was associated mainly with poorer trait-like executive function characteristics. Our findings suggest additionally that sleep duration and circadian rhythm associate with different domains of executive function, and there are no additive effects between the two. © 2017 European Sleep Research Society.

  19. RHYTHM DISTURBANCES DURING COLONOSCOPY

    Directory of Open Access Journals (Sweden)

    D. Jordanov

    2012-08-01

    Full Text Available Purpose: The purpose of this study is to assess the risk of inducing rhythm disturbances of the heart during colonoscopy.Patients and methods used: 80 patients had undergone colonoscopyper formed by two experienced specialists of endoscopy for the period from March to December 2011. The endoscopies were performed without premedication and sedation. Holter was placed on each patient one hour before the endoscopic examination, and the record continued one hour after the manipulation. The blood pressure was measured before, during and after the procedure.Results: During colonoscopy 25 patients (31,25% manifested rhythm disorders. In 15 patients (18,75% sinus tachycardia occurred. In 7 patients (8,75% suptraventricular extra systoles were observed and in 3 patients (3,75% - ventricular extra systoles. No ST-T changes were found. Highest values of the blood pressure were measured before and during the endoscopy, but the values did not exceed 160/105 mmHg. In 10 patients (12,5% a hypotensive reaction was observed, bur the values were not lower than 80/ 50. In 2 patients there was a short bradycardia with a heart frequency 50-55 /min.Conclusions: Our results showed that the rhythm disorders during lower colonoscopy occur in approximately 1/3 of the examined patients, there is an increase or decrease of the blood pressure in some patients, but that doesn’t require physician’s aid and the examination can be carried out safely without monitoring.

  20. Circadian melatonin concentration rhythm is lost in pregnant women with altered blood pressure rhythm.

    Science.gov (United States)

    Tranquilli, A L; Turi, A; Giannubilo, S R; Garbati, E

    2004-03-01

    We assessed the correlation between the rhythm of melatonin concentration and circadian blood pressure patterns in normal and hypertensive pregnancy. Ambulatory 24-h blood pressure and blood samples every 4 h were monitored in 16 primigravidae who had shown an abnormal circadian blood pressure pattern (eight pre-eclamptic and eight normotensive) in pregnancy and 6-12 months after pregnancy. The circadian rhythm was analyzed by chronobiological measures. Eight normotensive women with maintained blood pressure rhythm served as controls. During pregnancy, melatonin concentration was significantly higher in pre-eclamptic than in normotensive women (pre-eclampsia, 29.4 +/- 1.9 pg/ml, normotensin, altered rhythm, 15.6 +/- 2.1; controls, 22.7 +/- 1.8; p lost in all pregnant women with loss of blood pressure rhythm. After pregnancy, normotensive women showed a reappearance of both melatonin and blood pressure rhythm, whereas pre-eclamptic women showed a reappearance of blood pressure but not melatonin rhythm. The loss of blood pressure rhythm in pregnancy is consistent with the loss of melatonin concentration rhythm. In pre-eclamptic women, the normalization of blood pressure rhythm, while melatonin rhythm remained altered, suggests a temporal or causal priority of circadian concentration of melatonin in the determination of blood pressure trend.

  1. Visible Battle Rhythm

    National Research Council Canada - National Science Library

    Cort, Brian; Bouchard, Alain; Gouin, Denis; Proulx, Pascale; Wright, William

    2006-01-01

    .... Visual Battle Rhythm (VBR) is a software prototype which updates the battle rhythm process with modern technology and careful information design to improve the synchronization, situational awareness and decision making ability of commanders...

  2. Star Formation in Irregular Galaxies.

    Science.gov (United States)

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  3. Cross-cultural influences on rhythm processing: reproduction, discrimination, and beat tapping.

    Science.gov (United States)

    Cameron, Daniel J; Bentley, Jocelyn; Grahn, Jessica A

    2015-01-01

    The structures of musical rhythm differ between cultures, despite the fact that the ability to entrain movement to musical rhythm occurs in virtually all individuals across cultures. To measure the influence of culture on rhythm processing, we tested East African and North American adults on perception, production, and beat tapping for rhythms derived from East African and Western music. To assess rhythm perception, participants identified whether pairs of rhythms were the same or different. To assess rhythm production, participants reproduced rhythms after hearing them. To assess beat tapping, participants tapped the beat along with repeated rhythms. We expected that performance in all three tasks would be influenced by the culture of the participant and the culture of the rhythm. Specifically, we predicted that a participant's ability to discriminate, reproduce, and accurately tap the beat would be better for rhythms from their own culture than for rhythms from another culture. In the rhythm discrimination task, there were no differences in discriminating culturally familiar and unfamiliar rhythms. In the rhythm reproduction task, both groups reproduced East African rhythms more accurately than Western rhythms, but East African participants also showed an effect of cultural familiarity, leading to a significant interaction. In the beat tapping task, participants in both groups tapped the beat more accurately for culturally familiar than for unfamiliar rhythms. Moreover, there were differences between the two participant groups, and between the two types of rhythms, in the metrical level selected for beat tapping. The results demonstrate that culture does influence the processing of musical rhythm. In terms of the function of musical rhythm, our results are consistent with theories that musical rhythm enables synchronization. Musical rhythm may foster musical cultural identity by enabling within-group synchronization to music, perhaps supporting social cohesion.

  4. Markets, Bodies, Rhythms

    DEFF Research Database (Denmark)

    Borch, Christian; Bondo Hansen, Kristian; Lange, Ann-Christina

    2015-01-01

    to respond to a widely perceived problem, namely that market rhythms might be contagious and that some form of separation of bodily and market rhythms might therefore be needed. Finally, we show how current high-frequency trading, despite being purely algorithmic, does not render the traders' bodies......This article explores the relationship between bodily rhythms and market rhythms in two distinctly different financial market configurations, namely the open-outcry pit (prevalent especially in the early 20th century) and present-day high-frequency trading. Drawing on Henri Lefebvre......'s rhythmanalysis, we show how traders seek to calibrate their bodily rhythms to those of the market. We argue that, in the case of early-20th-century open-outcry trading pits, traders tried to enact a total merger of bodily and market rhythms. We also demonstrate how, in the 1920s and '30s, market observers began...

  5. Circadian Rhythm Sleep Disorders

    Directory of Open Access Journals (Sweden)

    Erhan Akinci

    2016-06-01

    Full Text Available The circadian rhythm sleep disorders define the clinical conditions where sleep and ndash;wake rhythm is disrupted despite optimum environmental and social conditions. They occur as a result of the changes in endogenous circadian hours or non-compatibility of environmental factors or social life with endogenous circadian rhythm. The sleep and ndash;wake rhythm is disrupted continuously or in repeating phases depending on lack of balance between internal and external cycles. This condition leads to functional impairments which cause insomnia, excessive sleepiness or both in people. Application of detailed sleep anamnesis and sleep diary with actigraphy record, if possible, will be sufficient for diagnosis. The treatment aims to align endogenous circadian rhythm with environmental conditions. The purpose of this article is to review pathology, clinical characteristics, diagnosis and treatment of circadian rhythm disorder. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 178-189

  6. Cross-Cultural Influences on Rhythm Processing: Reproduction, Discrimination, and Beat Tapping

    Directory of Open Access Journals (Sweden)

    Daniel J Cameron

    2015-04-01

    Full Text Available The structures of musical rhythm differ between cultures, despite the fact that the ability to synchronize one’s movements to musical rhythms appears to be universal. To measure the influence of culture on rhythm processing, we tested East African and North American adults on the perception, production, and beat tapping of rhythms derived from East African and Western music. To assess rhythm perception, participants identified whether pairs of rhythms were same or different. To assess rhythm production, participants reproduced rhythms after hearing them. To assess beat tapping, participants tapped the beat along with repeated rhythms. We expected that performance in all three tasks would be influenced both by the culture of the participant and by the culture of the rhythm. Specifically, we predicted that a participant’s ability to discriminate, reproduce, and accurately tap the beat would be better for rhythms from their own culture than for rhythms from another culture. In the rhythm discrimination task, there were no differences in discriminating culturally familiar and unfamiliar rhythms. In the rhythm reproduction task, both groups reproduced East African rhythms more accurately than Western rhythms, but East African participants also showed an effect of cultural familiarity, leading to a significant interaction. In the beat tapping task, participants in both groups tapped the beat more accurately for culturally familiar than unfamiliar rhythms. The results demonstrate that culture does influence the processing of musical rhythm. In terms of the function of musical rhythm, our results are consistent with theories that musical rhythm enables synchronization. Musical rhythm may foster musical cultural identity by enabling within-group synchronization to music, perhaps supporting social cohesion.

  7. Dim light at night disrupts molecular circadian rhythms and increases body weight.

    Science.gov (United States)

    Fonken, Laura K; Aubrecht, Taryn G; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

    2013-08-01

    With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.

  8. Treatment guidelines for Circadian Rhythm Sleep-Wake Disorders of the Polish Sleep Research Society and the Section of Biological Psychiatry of the Polish Psychiatric Association. Part I. Physiology, assessment and therapeutic methods.

    Science.gov (United States)

    Wichniak, Adam; Jankowski, Konrad S; Skalski, Michal; Skwarło-Sońta, Krystyna; Zawilska, Jolanta B; Żarowski, Marcin; Poradowska, Ewa; Jernajczyk, Wojciech

    2017-10-29

    Majority of the physiological processes in the human organism are rhythmic. The most common are the diurnal changes that repeat roughly every 24 hours, called circadian rhythms. Circadian rhythms disorders have negative influence on human functioning. The aim of this article is to present the current understanding of the circadian rhythms physiological role, with particular emphasis on the circadian rhythm sleep-wake disorders (CRSWD), principles of their diagnosis and chronobiological therapy. The guidelines are based on the review of recommendations from the scientific societies involved in sleep medicine and the clinical experiences of the authors. Researchers participating in the preparation of guidelines were invited by the Polish Sleep Research Society and the Section of Biological Psychiatry of the Polish Psychiatric Association, based on their significant contributions in circadian rhythm research and/or clinical experience in the treatment of such disorders. Finally, the guidelines were adjusted to the questions and comments given by the members of both Societies. CRSWD have a significant negative impact on human health and functioning. Standard methods used to assess CRSWD are sleep diaries and sleep logs, while the actigraphy, when available, should be also used. The most effective methods of CRSWD treatment are melatonin administration and light therapy. Behavioral interventions are also recommended. Afourteen-day period of sleep-wake rhythm assessment in CRSWD enables accurate diagnosis, adequate selection of chronobiological interventions, and planning adequate diurnal timing of their application. This type of assessment is quite easy, low-cost, and provides valuable indications how to adjust the therapeutic approach to the circadian phase of the particular patient.

  9. Chronotype and circadian rhythm in bipolar disorder: A systematic review.

    Science.gov (United States)

    Melo, Matias C A; Abreu, Rafael L C; Linhares Neto, Vicente B; de Bruin, Pedro F C; de Bruin, Veralice M S

    2017-08-01

    Despite a complex relationship between mood, sleep and rhythm, the impact of circadian disruptions on bipolar disorder (BD) has not been clarified. The purpose of this systematic review was to define current evidence regarding chronotype and circadian rhythm patterns in BD patients. 42 studies were included, involving 3432 BD patients. Disruption of the biological rhythm was identified, even in drug-naïve BD patients and independently of mood status. Daily profiles of melatonin levels and cortisol indicated a delayed phase. Depression was more frequently associated with circadian alterations than euthymia. Few studies evaluated mania, demonstrating irregular rhythms. Evening type was more common in BD adults. Studies about the influence of chronotype on depressive symptoms showed conflicting results. Only one investigation observed the influences of chronotype in mania, revealing no significant association. Effects of psychoeducation and lithium on rhythm in BD patients were poorly studied, demonstrating no improvement of rhythm parameters. Studies about genetics are incipient. In conclusion, disruption in circadian rhythm and eveningness are common in BD. Prospective research evaluating the impact of circadian disruption on mood symptoms, metabolism, seasonality, the influence of age and the effects of mood stabilizers are needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Rhythm in language acquisition.

    Science.gov (United States)

    Langus, Alan; Mehler, Jacques; Nespor, Marina

    2017-10-01

    Spoken language is governed by rhythm. Linguistic rhythm is hierarchical and the rhythmic hierarchy partially mimics the prosodic as well as the morpho-syntactic hierarchy of spoken language. It can thus provide learners with cues about the structure of the language they are acquiring. We identify three universal levels of linguistic rhythm - the segmental level, the level of the metrical feet and the phonological phrase level - and discuss why primary lexical stress is not rhythmic. We survey experimental evidence on rhythm perception in young infants and native speakers of various languages to determine the properties of linguistic rhythm that are present at birth, those that mature during the first year of life and those that are shaped by the linguistic environment of language learners. We conclude with a discussion of the major gaps in current knowledge on linguistic rhythm and highlight areas of interest for future research that are most likely to yield significant insights into the nature, the perception, and the usefulness of linguistic rhythm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Bleeding risk assessment and management in atrial fibrillation patients. Executive Summary of a Position Document from the European Heart Rhythm Association [EHRA], endorsed by the European Society of Cardiology [ESC] Working Group on Thrombosis

    NARCIS (Netherlands)

    Lip, Gregory Y. H.; Andreotti, Felicita; Fauchier, Laurent; Huber, Kurt; Hylek, Elaine; Knight, Eve; Lane, Deirdre; Levi, Marcel; Marín, Francisco; Palareti, Gualtiero; Kirchhof, Paulus

    2011-01-01

    In this executive summary of a Consensus Document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in atrial fibrillation (AF)

  12. Saturn's Irregular Moon Ymir

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2012-10-01

    Ymir (diameter 18 km), Saturn's second largest retrograde outer or irregular moon, has been observed six times by the Cassini narrow-angle camera (NAC) during the first 7 months in 2012. The observations span phase angles from 2° up to 102° and were taken at ranges between 15 and 18 million kilometers. From such a distance, Ymir is smaller than a pixel in the Cassini NAC. The data reveal a sidereal rotation period of 11.93 hrs, which is 1.6x longer than the previously reported value (Denk et al. 2011, EPSC/DPS #1452). Reason for this discrepancy is that the rotational light curve shows a rather uncommon 3-maxima and 3-minima shape at least in the phase angle range 50° to 100°, which was not recognizable in earlier data. The data cover several rotations from different viewing and illumination geometries and allow for a convex shape inversion with possibly a unique solution for the pole direction. The model reproduces the observed light curves to a very good accuracy without requiring albedo variegation, thereby suggesting that the lightcurve is dominated by the shape of Ymir. Among Saturn's irregular moons, the phenomenon of more than two maxima and minima at moderate to high phase angles is not unique to Ymir. At least Siarnaq and Paaliaq also show light curves with a strong deviation from a double-sine curve. Their rotation periods, however, remain unknown until more data can be taken. The light curve of Phoebe is fundamentally different to Ymir's because it is mainly shaped by local albedo differences and not by shape. Other reliable rotation periods of irregular satellites measured by Cassini include: Mundilfari 6.74 h; Kari 7.70 h; Albiorix 13.32 h; Kiviuq 21.82 h. More uncertain values are: Skathi 12 h; Bebhionn 16 h; Thrymr 27 h; Erriapus 28 h.

  13. Social Rhythm and Mental Health: A Cross-Cultural Comparison.

    Directory of Open Access Journals (Sweden)

    Jürgen Margraf

    Full Text Available Social rhythm refers to the regularity with which one engages in social activities throughout the week, and has established links with bipolar disorder, as well as some links with depression and anxiety. The aim of the present study is to examine social rhythm and its relationship to various aspects of health, including physical health, negative mental health, and positive mental health.Questionnaire data were obtained from a large-scale multi-national sample of 8095 representative participants from the U.S., Russia, and Germany.Results indicated that social rhythm irregularity is related to increased reporting of health problems, depression, anxiety, and stress. In contrast, greater regularity is related to better overall health state, life satisfaction, and positive mental health. The effects are generally small in size, but hold even when controlling for gender, marital status, education, income, country, and social support. Further, social rhythm means differ across Russia, the U.S., and Germany. Relationships with mental health are present in all three countries, but differ in magnitude.Social rhythm irregularity is related to mental health in Russia, the U.S., and Germany.

  14. Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing.

    Science.gov (United States)

    Phillips, Andrew J K; Clerx, William M; O'Brien, Conor S; Sano, Akane; Barger, Laura K; Picard, Rosalind W; Lockley, Steven W; Klerman, Elizabeth B; Czeisler, Charles A

    2017-06-12

    The association of irregular sleep schedules with circadian timing and academic performance has not been systematically examined. We studied 61 undergraduates for 30 days using sleep diaries, and quantified sleep regularity using a novel metric, the sleep regularity index (SRI). In the most and least regular quintiles, circadian phase and light exposure were assessed using salivary dim-light melatonin onset (DLMO) and wrist-worn photometry, respectively. DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p academic performance and SRI was observed. These findings show that irregular sleep and light exposure patterns in college students are associated with delayed circadian rhythms and lower academic performance. Moreover, the modeling results reveal that light-based interventions may be therapeutically effective in improving sleep regularity in this population.

  15. Irregular Migrants and the Law

    OpenAIRE

    Kassim, Azizah; Mat Zin, Ragayah Hj.

    2013-01-01

    This paper examines Malaysia`s policy on irregular migrants and its implementation, and discusses its impact. A survey and interview covering 404 respondents was conducted between July 2010 and June 2011 to ascertain the real situations surrounding irregular migrants in Malaysia, which is one of the major host countries of international migrants from developing nations. The policy on foreign workers was formulated in the mid-1980s to deal with the large number of irregular migrants and their ...

  16. Strategic Analysis of Irregular Warfare

    Science.gov (United States)

    2010-03-01

    the same mathematical equations used by Lanchester .10 Irregular Warfare Theory and Doctrine It is time to develop new analytical methods and models...basis on which to build, similar to what Lanchester provided almost 100 years ago. Figure 9 portrays both Lanchester’s approach and an irregular 17

  17. Speech rhythm facilitates syntactic ambiguity resolution: ERP evidence.

    Directory of Open Access Journals (Sweden)

    Maria Paula Roncaglia-Denissen

    Full Text Available In the current event-related potential (ERP study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first. Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing.

  18. Speech rhythm facilitates syntactic ambiguity resolution: ERP evidence.

    Science.gov (United States)

    Roncaglia-Denissen, Maria Paula; Schmidt-Kassow, Maren; Kotz, Sonja A

    2013-01-01

    In the current event-related potential (ERP) study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first). Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing.

  19. RHYTHM STRUCTURE IN NEWS READING

    Directory of Open Access Journals (Sweden)

    Lluís Mas Manchón

    2013-06-01

    Full Text Available Rhythm is central to news reading in radio and television programs. This paper proposes a three level structure for rhythm in news discourse. It gives a comprehensive definition of rhythm and types of rhythm. Firstly, the Base Rhythm Structure consists of semantic and pragmatic rhythmic accents, coincident with very specific words. Secondly, these accents are grouped together according to type, frequency and order, thereby configuring three types of “rhythmic units” (the Internal Rhythm Structure: starting, main and end units. A last structure level presents four discursive factors that are very important in integrating the overall time structure of news announcing (the Melodic Rhythm Structure. This integral structure for news announcing rhythm should be further tested in acoustic-experimental studies under the criterion of information transmission efficacy.

  20. Light Rhythms in Architecture

    DEFF Research Database (Denmark)

    Bülow, Katja

    2013-01-01

    formation and rhythm. When integrated into an architectural concept, electrical lighting non-intended for poetic composition has the ability to contribute to place, time, and function-telling aspects of places in urban contexts. Urban environments are information wise challenging to pre-historic human...

  1. Biological Clocks & Circadian Rhythms

    Science.gov (United States)

    Robertson, Laura; Jones, M. Gail

    2009-01-01

    The study of biological clocks and circadian rhythms is an excellent way to address the inquiry strand in the National Science Education Standards (NSES) (NRC 1996). Students can study these everyday phenomena by designing experiments, gathering and analyzing data, and generating new experiments. As students explore biological clocks and circadian…

  2. Uncovering beat deafness: detecting rhythm disorders with synchronized finger tapping and perceptual timing tasks.

    Science.gov (United States)

    Dalla Bella, Simone; Sowiński, Jakub

    2015-03-16

    A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson's disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder).

  3. Children's Aural and Kinesthetic Understanding of Rhythm: Developing an Instructional Model

    Science.gov (United States)

    Foley, Adam D.

    2013-01-01

    The purpose of this study was to develop a deeper understanding of aural and kinesthetic rhythm skill development in elementary school-age children. In this study, I examined my curriculum model for rhythm understanding, which included creating and implementing assessments of movement skills in meter and rhythm. The research questions were: 1.…

  4. Irregular Dwarf Galaxy IC 1613

    Science.gov (United States)

    2005-01-01

    Ultraviolet image (left) and visual image (right) of the irregular dwarf galaxy IC 1613. Low surface brightness galaxies, such as IC 1613, are more easily detected in the ultraviolet because of the low background levels compared to visual wavelengths.

  5. Rhythm-based heartbeat duration normalization for atrial fibrillation detection.

    Science.gov (United States)

    Islam, Md Saiful; Ammour, Nassim; Alajlan, Naif; Aboalsamh, Hatim

    2016-05-01

    Screening of atrial fibrillation (AF) for high-risk patients including all patients aged 65 years and older is important for prevention of risk of stroke. Different technologies such as modified blood pressure monitor, single lead ECG-based finger-probe, and smart phone using plethysmogram signal have been emerging for this purpose. All these technologies use irregularity of heartbeat duration as a feature for AF detection. We have investigated a normalization method of heartbeat duration for improved AF detection. AF is an arrhythmia in which heartbeat duration generally becomes irregularly irregular. From a window of heartbeat duration, we estimate the possible rhythm of the majority of heartbeats and normalize duration of all heartbeats in the window based on the rhythm so that we can measure the irregularity of heartbeats for both AF and non-AF rhythms in the same scale. Irregularity is measured by the entropy of distribution of the normalized duration. Then we classify a window of heartbeats as AF or non-AF by thresholding the measured irregularity. The effect of this normalization is evaluated by comparing AF detection performances using duration with the normalization, without normalization, and with other existing normalizations. Sensitivity and specificity of AF detection using normalized heartbeat duration were tested on two landmark databases available online and compared with results of other methods (with/without normalization) by receiver operating characteristic (ROC) curves. ROC analysis showed that the normalization was able to improve the performance of AF detection and it was consistent for a wide range of sensitivity and specificity for use of different thresholds. Detection accuracy was also computed for equal rates of sensitivity and specificity for different methods. Using normalized heartbeat duration, we obtained 96.38% accuracy which is more than 4% improvement compared to AF detection without normalization. The proposed normalization

  6. Circadian Rhythms in Cyanobacteria

    Science.gov (United States)

    Golden, Susan S.

    2015-01-01

    SUMMARY Life on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms, generated by a circadian clock, control temporal programs of cellular physiology to facilitate adaptation to daily environmental changes. Circadian rhythms are nearly ubiquitous and are found in both prokaryotic and eukaryotic organisms. Here we introduce the molecular mechanism of the circadian clock in the model cyanobacterium Synechococcus elongatus PCC 7942. We review the current understanding of the cyanobacterial clock, emphasizing recent work that has generated a more comprehensive understanding of how the circadian oscillator becomes synchronized with the external environment and how information from the oscillator is transmitted to generate rhythms of biological activity. These results have changed how we think about the clock, shifting away from a linear model to one in which the clock is viewed as an interactive network of multifunctional components that are integrated into the context of the cell in order to pace and reset the oscillator. We conclude with a discussion of how this basic timekeeping mechanism differs in other cyanobacterial species and how information gleaned from work in cyanobacteria can be translated to understanding rhythmic phenomena in other prokaryotic systems. PMID:26335718

  7. Irregular Challenges 2010 Game

    Science.gov (United States)

    2010-10-22

    Issues Sea based C2 platforms, establish common operating picture ( COP ), coordination with shore based NGO/IGO White Cell players assessed a... slaughtered . • Large numbers of transplanted Muslims among the dead. • Remnants of Niger Delta separatist movement still simmering • Cease fire is

  8. Transcutaneous electrical nerve stimulation (TENS) improves circadian rhythm disturbances in Alzheimer disease

    NARCIS (Netherlands)

    van Someren, E. J.; Scherder, E. J.; Swaab, D. F.

    1998-01-01

    In patients with Alzheimer disease (AD), an irregular day-night rhythm with behavioral restlessness during the night makes a strong demand on caregivers and is among the most important reasons for institutionalization. A dysfunctioning circadian timing system is supposed to underlie the disturbance

  9. Light Rhythms in Architecture

    DEFF Research Database (Denmark)

    Bülow, Katja

    2013-01-01

    On one hand, urban lighting expresses itself in a complex visual environment made by the interplay by between many separate lighting schemes, as street lighting, shop lighting, luminous commercials etc. On the other, a noticeable order of patterns occurs, when lighting is observed as luminous...... formation and rhythm. When integrated into an architectural concept, electrical lighting non-intended for poetic composition has the ability to contribute to place, time, and function-telling aspects of places in urban contexts. Urban environments are information wise challenging to pre-historic human...... instincts, but they can be met by careful selection and adjustment of existing light situations....

  10. Orchestrating intensities and rhythms

    DEFF Research Database (Denmark)

    Staunæs, Dorthe; Juelskjær, Malou

    2016-01-01

    environmentality and learning-centered governance standards has dramatic and performative effects for the production of (educational) subjectivities. This implies a shift from governing identities, categories and structures towards orchestrating affective intensities and rhythms. Finally, the article discusses...... and the making of subjects have held sway for many years; and it is also well known that schools have been some of the most regular purchasers of psychological methods, tests and classifications. Following but also elaborating upon governmentality studies, it is suggested that a current shift towards...

  11. Relation between functional connectivity and rhythm discrimination in children who do and do not stutter

    Directory of Open Access Journals (Sweden)

    Soo-Eun Chang

    2016-01-01

    Full Text Available Our ability to perceive and produce rhythmic patterns in the environment supports fundamental human capacities ranging from music and language processing to the coordination of action. This article considers whether spontaneous correlated brain activity within a basal ganglia-thalamocortical (rhythm network is associated with individual differences in auditory rhythm discrimination. Moreover, do children who stutter with demonstrated deficits in rhythm perception have weaker links between rhythm network functional connectivity and rhythm discrimination? All children in the study underwent a resting-state fMRI session, from which functional connectivity measures within the rhythm network were extracted from spontaneous brain activity. In a separate session, the same children completed an auditory rhythm-discrimination task, where behavioral performance was assessed using signal detection analysis. We hypothesized that in typically developing children, rhythm network functional connectivity would be associated with behavioral performance on the rhythm discrimination task, but that this relationship would be attenuated in children who stutter. Results supported our hypotheses, lending strong support for the view that (1 children who stutter have weaker rhythm network connectivity and (2 the lack of a relation between rhythm network connectivity and rhythm discrimination in children who stutter may be an important contributing factor to the etiology of stuttering.

  12. Sleep, Memory & Brain Rhythms.

    Science.gov (United States)

    Watson, Brendon O; Buzsáki, György

    2015-01-01

    Sleep occupies roughly one-third of our lives, yet the scientific community is still not entirely clear on its purpose or function. Existing data point most strongly to its role in memory and homeostasis: that sleep helps maintain basic brain functioning via a homeostatic mechanism that loosens connections between overworked synapses, and that sleep helps consolidate and re-form important memories. In this review, we will summarize these theories, but also focus on substantial new information regarding the relation of electrical brain rhythms to sleep. In particular, while REM sleep may contribute to the homeostatic weakening of overactive synapses, a prominent and transient oscillatory rhythm called "sharp-wave ripple" seems to allow for consolidation of behaviorally relevant memories across many structures of the brain. We propose that a theory of sleep involving the division of labor between two states of sleep-REM and non-REM, the latter of which has an abundance of ripple electrical activity-might allow for a fusion of the two main sleep theories. This theory then postulates that sleep performs a combination of consolidation and homeostasis that promotes optimal knowledge retention as well as optimal waking brain function.

  13. Circadian rhythms regulate amelogenesis.

    Science.gov (United States)

    Zheng, Li; Seon, Yoon Ji; Mourão, Marcio A; Schnell, Santiago; Kim, Doohak; Harada, Hidemitsu; Papagerakis, Silvana; Papagerakis, Petros

    2013-07-01

    Ameloblasts, the cells responsible for making enamel, modify their morphological features in response to specialized functions necessary for synchronized ameloblast differentiation and enamel formation. Secretory and maturation ameloblasts are characterized by the expression of stage-specific genes which follows strictly controlled repetitive patterns. Circadian rhythms are recognized as key regulators of the development and diseases of many tissues including bone. Our aim was to gain novel insights on the role of clock genes in enamel formation and to explore the potential links between circadian rhythms and amelogenesis. Our data shows definitive evidence that the main clock genes (Bmal1, Clock, Per1 and Per2) oscillate in ameloblasts at regular circadian (24 h) intervals both at RNA and protein levels. This study also reveals that the two markers of ameloblast differentiation i.e. amelogenin (Amelx; a marker of secretory stage ameloblasts) and kallikrein-related peptidase 4 (Klk4, a marker of maturation stage ameloblasts) are downstream targets of clock genes. Both, Amelx and Klk4 show 24h oscillatory expression patterns and their expression levels are up-regulated after Bmal1 over-expression in HAT-7 ameloblast cells. Taken together, these data suggest that both the secretory and the maturation stages of amelogenesis might be under circadian control. Changes in clock gene expression patterns might result in significant alterations of enamel apposition and mineralization. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. GARCH and Irregularly Spaced Data

    NARCIS (Netherlands)

    Meddahi, N.; Renault, E.; Werker, B.J.M.

    2003-01-01

    An exact discretization of continuous time stochastic volatility processes observed at irregularly spaced times is used to give insights on how a coherent GARCH model can be specified for such data. The relation of our approach with those in the existing literature is studied.

  15. The Rhetorical Nature of Rhythm

    NARCIS (Netherlands)

    Balint, Mihaela; Dascalu, Mihai; Trausan-Matu, Stefan

    2017-01-01

    Up to date, linguistic rhythm has been studied for speech, but the rhythm of written texts has been merely recognized, and not analyzed or interpreted in connection to natural language tasks. We provide an extension of the textual rhythmic features we proposed in previous work, and

  16. Clinical skills: cardiac rhythm recognition and monitoring.

    Science.gov (United States)

    Sharman, Joanna

    With technological advances, changes in provision of healthcare services and increasing pressure on critical care services, ward patients' severity of illness is ever increasing. As such, nurses need to develop their skills and knowledge to care for their client group. Competency in cardiac rhythm monitoring is beneficial to identify changes in cardiac status, assess response to treatment, diagnosis and post-surgical monitoring. This paper describes the basic anatomy and physiology of the heart and its conduction system, and explains a simple and easy to remember process of analysing cardiac rhythms (Resuscitation Council UK, 2000) that can be used in first-line assessment to assist healthcare practitioners in providing care to their patients.

  17. Dissipative structures and biological rhythms

    Science.gov (United States)

    Goldbeter, Albert

    2017-10-01

    Sustained oscillations abound in biological systems. They occur at all levels of biological organization over a wide range of periods, from a fraction of a second to years, and with a variety of underlying mechanisms. They control major physiological functions, and their dysfunction is associated with a variety of physiological disorders. The goal of this review is (i) to give an overview of the main rhythms observed at the cellular and supracellular levels, (ii) to briefly describe how the study of biological rhythms unfolded in the course of time, in parallel with studies on chemical oscillations, (iii) to present the major roles of biological rhythms in the control of physiological functions, and (iv) the pathologies associated with the alteration, disappearance, or spurious occurrence of biological rhythms. Two tables present the main examples of cellular and supracellular rhythms ordered according to their period, and their role in physiology and pathophysiology. Among the rhythms discussed are neural and cardiac rhythms, metabolic oscillations such as those occurring in glycolysis in yeast, intracellular Ca++ oscillations, cyclic AMP oscillations in Dictyostelium amoebae, the segmentation clock that controls somitogenesis, pulsatile hormone secretion, circadian rhythms which occur in all eukaryotes and some bacteria with a period close to 24 h, the oscillatory dynamics of the enzymatic network driving the cell cycle, and oscillations in transcription factors such as NF-ΚB and tumor suppressors such as p53. Ilya Prigogine's concept of dissipative structures applies to temporal oscillations and allows us to unify within a common framework the various rhythms observed at different levels of biological organization, regardless of their period and underlying mechanism.

  18. How Two Players Negotiate Rhythm in a Shared Rhythm Game

    DEFF Research Database (Denmark)

    Hansen, Anne-Marie; Andersen, Hans Jørgen; Raudaskoski, Pirkko Liisa

    2012-01-01

    from each other. Video analysis of user interaction shines light upon how users engaged in a rhythmical relationship, and interviews give information about the user experience in terms of the game play and user collaboration. Based on the findings in this paper we propose design guidelines......In a design and working prototype of a shared music interface eleven teams of two people were to collaborate about filling in holes with tones and beats in an evolving ground rhythm. The hypothesis was that users would tune into each other and have sections of characteristic rhythmical...... relationships that related to the ground rhythm. Results from interaction data show that teams did find a mutual rhythm, and that they were able to keep this rhythm for a while and/or over several small periods. Results also showed that two players engaged in very specific rhythmical relationships that differed...

  19. Circadian rhythms in handwriting kinematics and legibility.

    Science.gov (United States)

    Jasper, Isabelle; Gordijn, Marijke; Häussler, Andreas; Hermsdörfer, Joachim

    2011-08-01

    The aim of the present study was to analyze the circadian rhythmicity in handwriting kinematics and legibility and to compare the performance between Dutch and German writers. Two subject groups underwent a 40 h sleep deprivation protocol under Constant Routine conditions either in Groningen (10 Dutch subjects) or in Berlin (9 German subjects). Both groups wrote every 3h a test sentence of similar structure in their native language. Kinematic handwriting performance was assessed with a digitizing tablet and evaluated by writing speed, writing fluency, and script size. Writing speed (frequency of strokes and average velocity) revealed a clear circadian rhythm, with a parallel decline during night and a minimum around 3:00 h in the morning for both groups. Script size and movement fluency did not vary with time of day in neither group. Legibility of handwriting was evaluated by intra-individually ranking handwriting specimens of the 13 sessions by 10 German and 10 Dutch raters. Whereas legibility ratings of the German handwriting specimens deteriorated during night in parallel with slower writing speed, legibility of the Dutch handwriting deteriorated not until the next morning. In conclusion, the circadian rhythm of handwriting kinematics seems to be independent of script language at least among the two tested western countries. Moreover, handwriting legibility is also subject to a circadian rhythm which, however, seems to be influenced by variations in the assessment protocol. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Learning by joining the rhythm

    DEFF Research Database (Denmark)

    Lund, Ole; Ravn, Susanne; Christensen, Mette Krogh

    2012-01-01

    This article aims to explore how a joint rhythm is learned. The exploration is based on a combination of a case study of training in elite rowing and theoretical considerations concerning mutual incorporation of skills in learning. In 2009 Juliane and Anne start to row the double sculler together....... The two rowers’ aim is to be among the exclusive group of teams that qualify for the Olympic Games three years later. However Anne is not a rower, and has to be apprenticed by Juliane, who is an experienced elite rower. One important learning goal in the apprenticeship is to find a good joint rhythm......, to be able to put optimal effort into the rowing. Thus the apprenticeship is about developing a sense for a good rhythm in Anne which corresponds to Juliane’s fine-grained sense of what a good rhythm should feel like. Our study suggests that apprenticeship learning has to be understood as an embodied...

  1. Find a Heart Rhythm Specialist

    Science.gov (United States)

    ... Taiwan Thailand Turkey United Arab Emirates United Kingdom Venezuela Vietnam Within 5 miles 10 miles 15 miles ... info@HRSonline.org © Heart Rhythm Society 2017 Privacy Policy | Linking Policy | Patient Education Disclaimer You are about ...

  2. Methodic of perfection of higher pedagogical educational establishments girl students’ rhythm

    Directory of Open Access Journals (Sweden)

    A.N. Kolumbet

    2016-06-01

    Full Text Available Purpose: to study influence of methodic of rhythm perfection on girl students’ coordination abilities. Material: in the research 264 girl students participated. We assessed individual and collective rhythm, internal and external motor rhythm; rhythm in exercises with musical accompaniment. Results: we have determined that creative motor tasks require variable conditions for their realization. We have proved demand in appropriate criteria for their assessment. It is noted that there is a demand in development of rhythm, considering its main kinds and manifestations, which are formed with some peculiarities. Individual rhythm is determined by activation of attention and its level. It is perfected more successfully rather with stimulated development than with natural. It was found that with age the character of natural progressing of rhythm preserves. Conclusions: it is recommended to develop rhythm in compliance with its kinds and manifestations. Progressing and perfection of rhythm is a long lasted process and shall be realized during all period of girl students’ studying. Such approach forms girl students’ demand in finding of purposeful motor rhythm in all their new motor actions. It ensures optimality of their fulfillment.

  3. Sympathetic rhythms and nervous integration.

    Science.gov (United States)

    Gilbey, Michael P

    2007-04-01

    1. The present review focuses on some of the processes producing rhythms in sympathetic nerves influencing cardiovascular functions and considers their potential relevance to nervous integration. 2. Two mechanisms are considered that may account for rhythmic sympathetic discharges. First, neuronal elements of peripheral or central origin produce rhythmic activity by phasically exciting and/or inhibiting neurons within central sympathetic networks. Second, rhythms arise within central sympathetic networks. Evidence is considered that indicates the operation of both mechanisms; the first in muscle and the second in skin sympathetic vasoconstrictor networks. 3. Sympathetic activity to the rat tail, a model for the nervous control of skin circulation, is regulated by central networks involved in thermoregulation and those associated with fear and arousal. In an anaesthetized preparation, activity displays an apparently autonomous rhythm (T-rhythm; 0.4-1.2 Hz) and the level of activity can be manipulated by regulating core body temperature. This model has been used to study rhythm generation in central sympathetic networks and possible functional relevance. 4. A unique insight provided by the T rhythm, into possible physiological function(s) underlying rhythmic sympathetic discharges is that the activity of single sympathetic post-ganglionic neurons within a population innervating the same target can have different rhythm frequencies. Therefore, the graded and dynamic entrainment of the rhythms by inputs, such as central respiratory drive and/or lung inflation-related afferent activity, can produce graded and dynamic synchronization of sympathetic discharges. The degree of synchronization may influence the efficacy of transmission in a target chain of excitable cells. 5. The T-rhythm may be generated within the spinal cord because the intrathecal application of 5-hydroxytryptamine at the L1 level of the spinal cord of a rat spinalized at T10-T11 produces a T-like rhythm

  4. Circadian rhythms and reproduction.

    Science.gov (United States)

    Boden, Michael J; Kennaway, David J

    2006-09-01

    There is a growing recognition that the circadian timing system, in particular recently discovered clock genes, plays a major role in a wide range of physiological systems. Microarray studies, for example, have shown that the expression of hundreds of genes changes many fold in the suprachiasmatic nucleus, liver heart and kidney. In this review, we discuss the role of circadian rhythmicity in the control of reproductive function in animals and humans. Circadian rhythms and clock genes appear to be involved in optimal reproductive performance, but there are sufficient redundancies in their function that many of the knockout mice produced do not show overt reproductive failure. Furthermore, important strain differences have emerged from the studies especially between the various Clock (Circadian Locomotor Output Cycle Kaput) mutant strains. Nevertheless, there is emerging evidence that the primary clock genes, Clock and Bmal1 (Brain and Muscle ARNT-like protein 1, also known as Mop3), strongly influence reproductive competency. The extent to which the circadian timing system affects human reproductive performance is not known, in part, because many of the appropriate studies have not been done. With the role of Clock and Bmal1 in fertility becoming clearer, it may be time to pursue the effect of polymorphisms in these genes in relation to the various types of infertility in humans.

  5. Irregular working hours and fatigue of cabin crew.

    Science.gov (United States)

    Castro, Marta; Carvalhais, José; Teles, Júlia

    2015-01-01

    Beyond workload and specific environmental factors, flight attendants can be exposed to irregular working hours, conflicting with their circadian rhythms and having a negative impact in sleep, fatigue, health, social and family life, and performance which is critical to both safety and security in flight operations. This study focuses on the irregular schedules of cabin crew as a trigger of fatigue symptoms in a wet lease Portuguese airline. The aim was to analyze: what are the requirements of the cabin crew work; whether the schedules being observed and effective resting timeouts are triggering factors of fatigue; and the existence of fatigue symptoms in the cabin crew. A questionnaire has been adapted and applied to a sample of 73 cabin crew-members (representing 61.9% of the population), 39 females and 34 males, with an average age of 27.68 ± 4.27 years. Our data indicate the presence of fatigue and corresponding health symptoms among the airline cabin crew, despite of the sample favorable characteristics. Senior workers and women are more affected. Countermeasures are required. Recommendations can be made regarding the fatigue risk management, including work organization, education and awareness training programmes and specific countermeasures.

  6. An analysis of heart rhythm dynamics using a three-coupled oscillator model

    International Nuclear Information System (INIS)

    Gois, Sandra R.F.S.M.; Savi, Marcelo A.

    2009-01-01

    Rhythmic phenomena represent one of the most striking manifestations of the dynamic behavior in biological systems. Understanding the mechanisms responsible for biological rhythms is crucial for the comprehension of the dynamics of life. Natural rhythms could be either regular or irregular over time and space. Each kind of dynamical behavior may be related to both normal and pathological physiological functioning. The cardiac conducting system can be treated as a network of self-excitatory elements and, since these elements exhibit oscillatory behavior, they can be modeled as nonlinear oscillators. This paper proposes a mathematical model to describe heart rhythms considering three modified Van der Pol oscillators connected with time delay couplings. Therefore, the heart dynamics is represented by a system of differential difference equations. Numerical simulations are carried out presenting qualitative agreement with the general heart rhythm behavior. Normal and pathological rhythms represented by the ECG signals are reproduced. Pathological rhythms are generated by either the coupling alterations that represents communications aspects in the heart electric system or forcing excitation representing external pacemaker excitation.

  7. Shared Components of Rhythm Generation for Locomotion and Scratching Exist Prior to Motoneurons

    Directory of Open Access Journals (Sweden)

    Zhao-Zhe Hao

    2017-08-01

    Full Text Available Does the spinal cord use a single network to generate locomotor and scratching rhythms or two separate networks? Previous research showed that simultaneous swim and scratch stimulation (“dual stimulation” in immobilized, spinal turtles evokes a single rhythm in hindlimb motor nerves with a frequency often greater than during swim stimulation alone or scratch stimulation alone. This suggests that the signals that trigger swimming and scratching converge and are integrated within the spinal cord. However, these results could not determine whether the integration occurs in motoneurons themselves or earlier, in spinal interneurons. Here, we recorded intracellularly from hindlimb motoneurons during dual stimulation. Motoneuron membrane potentials displayed regular oscillations at a higher frequency during dual stimulation than during swim or scratch stimulation alone. In contrast, arithmetic addition of the oscillations during swimming alone and scratching alone with various delays always generated irregular oscillations. Also, the standard deviation of the phase-normalized membrane potential during dual stimulation was similar to those during swimming or scratching alone. In contrast, the standard deviation was greater when pooling cycles of swimming alone and scratching alone for two of the three forms of scratching. This shows that dual stimulation generates a single rhythm prior to motoneurons. Thus, either swimming and scratching largely share a rhythm generator or the two rhythms are integrated into one rhythm by strong interactions among interneurons.

  8. Low social rhythm regularity predicts first onset of bipolar spectrum disorders among at-risk individuals with reward hypersensitivity.

    Science.gov (United States)

    Alloy, Lauren B; Boland, Elaine M; Ng, Tommy H; Whitehouse, Wayne G; Abramson, Lyn Y

    2015-11-01

    The social zeitgeber model (Ehlers, Frank, & Kupfer, 1988) suggests that irregular daily schedules or social rhythms provide vulnerability to bipolar spectrum disorders. This study tested whether social rhythm regularity prospectively predicted first lifetime onset of bipolar spectrum disorders in adolescents already at risk for bipolar disorder based on exhibiting reward hypersensitivity. Adolescents (ages 14-19 years) previously screened to have high (n = 138) or moderate (n = 95) reward sensitivity, but no lifetime history of bipolar spectrum disorder, completed measures of depressive and manic symptoms, family history of bipolar disorder, and the Social Rhythm Metric. They were followed prospectively with semistructured diagnostic interviews every 6 months for an average of 31.7 (SD = 20.1) months. Hierarchical logistic regression indicated that low social rhythm regularity at baseline predicted greater likelihood of first onset of bipolar spectrum disorder over follow-up among high-reward-sensitivity adolescents but not moderate-reward-sensitivity adolescents, controlling for follow-up time, gender, age, family history of bipolar disorder, and initial manic and depressive symptoms (β = -.150, Wald = 4.365, p = .037, odds ratio = .861, 95% confidence interval [.748, .991]). Consistent with the social zeitgeber theory, low social rhythm regularity provides vulnerability to first onset of bipolar spectrum disorder among at-risk adolescents. It may be possible to identify adolescents at risk for developing a bipolar spectrum disorder based on exhibiting both reward hypersensitivity and social rhythm irregularity before onset occurs. (c) 2015 APA, all rights reserved).

  9. Irregular Migration in Jordan, 1995-2007

    OpenAIRE

    AROURI, Fathi A.

    2008-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) This paper tackles the question of irregular migration in Jordan through its four main aspects. The first concerns irregular labour migrants and has been approached by using figures showing the socio-economic profile of non Jordanians working in Jordan and, additionally, unemployment in Jordan. This is done by assuming close similarities between legal and irregular labour migrants. The second is an attemp...

  10. Timing of host feeding drives rhythms in parasite replication

    KAUST Repository

    Prior, Kimberley F.; van der Veen, Daan R.; O’ Donnell, Aidan J.; Cumnock, Katherine; Schneider, David; Pain, Arnab; Subudhi, Amit; Ramaprasad, Abhinay; Rund, Samuel S. C.; Savill, Nicholas J.; Reece, Sarah E.

    2018-01-01

    by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms. Further investigation reveals that parasite rhythms correlate closely with blood glucose rhythms. In addition, we show that parasite rhythms

  11. Social memory in the rat: circadian variation and effect of circadian rhythm disruption

    NARCIS (Netherlands)

    Reijmers, L.G.J.E.; Leus, I.E.; Burbach, J.P.H.; Spruijt, B.M.; Ree, van J.M.

    2001-01-01

    Disruption of circadian rhythm can impair long-term passive avoidance memory of rats and mice. The present study investigated whether disruption of circadian rhythm can also impair social memory of male rats. Social memory was assessed using the social discrimination test, in which a short-term

  12. Effect of Melodic Rhythm on Elementary Students' and College Undergraduates' Perceptions of Relative Tempo.

    Science.gov (United States)

    Duke, Robert A.

    1989-01-01

    Uses extant musical examples as stimuli in order to assess the effect of melodic rhythm as a determinant of relative tempo as perceived by college undergraduates and elementary students. Results indicate that subjects responded to the melodic rhythm as well as the beat when making tempo judgments. (LS)

  13. Computing proton dose to irregularly moving targets

    International Nuclear Information System (INIS)

    Phillips, Justin; Gueorguiev, Gueorgui; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C; Shackleford, James A

    2014-01-01

    Purpose: While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods: The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results: A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, 95.7% with 3 cm drift in

  14. Impact of chronodisruption during primate pregnancy on the maternal and newborn temperature rhythms.

    Directory of Open Access Journals (Sweden)

    María Serón-Ferré

    Full Text Available Disruption of the maternal environment during pregnancy is a key contributor to offspring diseases that develop in adult life. To explore the impact of chronodisruption during pregnancy in primates, we exposed pregnant capuchin monkeys to constant light (eliminating the maternal melatonin rhythm from the last third of gestation to term. Maternal temperature and activity circadian rhythms were assessed as well as the newborn temperature rhythm. Additionally we studied the effect of daily maternal melatonin replacement during pregnancy on these rhythms. Ten pregnant capuchin monkeys were exposed to constant light from 60% of gestation to term. Five received a daily oral dose of melatonin (250 µg kg/body weight at 1800 h (LL+Mel and the other five a placebo (LL. Six additional pregnant females were maintained in a 14∶10 light:dark cycles and their newborns were used as controls (LD. Rhythms were recorded 96 h before delivery in the mother and at 4-6 days of age in the newborn. Exposure to constant light had no effect on the maternal body temperature rhythm however it delayed the acrophase of the activity rhythm. Neither rhythm was affected by melatonin replacement. In contrast, maternal exposure to constant light affected the newborn body temperature rhythm. This rhythm was entrained in control newborns whereas LL newborns showed a random distribution of the acrophases over 24-h. In addition, mean temperature was decreased (34.0±0.6 vs 36.1±0.2°C, in LL and control, respectively P<0.05. Maternal melatonin replacement during pregnancy re-synchronized the acrophases and restored mean temperature to the values in control newborns. Our findings demonstrate that prenatal melatonin is a Zeitgeber for the newborn temperature rhythm and supports normal body temperature maintenance. Altogether these prenatal melatonin effects highlight the physiological importance of the maternal melatonin rhythm during pregnancy for the newborn primate.

  15. Maternal and infant activity: Analytic approaches for the study of circadian rhythm.

    Science.gov (United States)

    Thomas, Karen A; Burr, Robert L; Spieker, Susan

    2015-11-01

    The study of infant and mother circadian rhythm entails choice of instruments appropriate for use in the home environment as well as selection of analytic approach that characterizes circadian rhythm. While actigraphy monitoring suits the needs of home study, limited studies have examined mother and infant rhythm derived from actigraphy. Among this existing research a variety of analyses have been employed to characterize 24-h rhythm, reducing ability to evaluate and synthesize findings. Few studies have examined the correspondence of mother and infant circadian parameters for the most frequently cited approaches: cosinor, non-parametric circadian rhythm analysis (NPCRA), and autocorrelation function (ACF). The purpose of this research was to examine analytic approaches in the study of mother and infant circadian activity rhythm. Forty-three healthy mother and infant pairs were studied in the home environment over a 72h period at infant age 4, 8, and 12 weeks. Activity was recorded continuously using actigraphy monitors and mothers completed a diary. Parameters of circadian rhythm were generated from cosinor analysis, NPCRA, and ACF. The correlation among measures of rhythm center (cosinor mesor, NPCRA mid level), strength or fit of 24-h period (cosinor magnitude and R(2), NPCRA amplitude and relative amplitude (RA)), phase (cosinor acrophase, NPCRA M10 and L5 midpoint), and rhythm stability and variability (NPCRA interdaily stability (IS) and intradaily variability (IV), ACF) was assessed, and additionally the effect size (eta(2)) for change over time evaluated. Results suggest that cosinor analysis, NPCRA, and autocorrelation provide several comparable parameters of infant and maternal circadian rhythm center, fit, and phase. IS and IV were strongly correlated with the 24-h cycle fit. The circadian parameters analyzed offer separate insight into rhythm and differing effect size for the detection of change over time. Findings inform selection of analysis and

  16. Circadian rhythms in mitochondrial respiration

    NARCIS (Netherlands)

    de Goede, Paul; Wefers, Jakob; Brombacher, Eline Constance; Schrauwen, P; Kalsbeek, A.

    2018-01-01

    Many physiological processes are regulated with a 24h periodicity to anticipate the environmental changes of day to nighttime and vice versa. These 24h regulations, commonly termed circadian rhythms, amongst others control the sleep-wake cycle, locomotor activity and preparation for food

  17. Rhythm Deficits in "Tone Deafness"

    Science.gov (United States)

    Foxton, Jessica M.; Nandy, Rachel K.; Griffiths, Timothy D.

    2006-01-01

    It is commonly observed that "tone deaf" individuals are unable to hear the beat of a tune, yet deficits on simple timing tests have not been found. In this study, we investigated rhythm processing in nine individuals with congenital amusia ("tone deafness") and nine controls. Participants were presented with pairs of 5-note sequences, and were…

  18. Ethical issues in irregular migration research

    NARCIS (Netherlands)

    Duvell, F.; Triandafyllidou, A.; Vollmer, B.

    2008-01-01

    This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

  19. Current Conceptual Challenges in the Study of Rhythm Processing Deficits

    Directory of Open Access Journals (Sweden)

    Pauline eTranchant

    2015-06-01

    Full Text Available Interest in the study of rhythm processing deficits (RPD is currently growing in the cognitive neuroscience community, as this type of investigation constitutes a powerful tool for the understanding of normal rhythm processing. Because this field is in its infancy, it still lacks a common conceptual vocabulary to facilitate effective communication between different researchers and research groups. In this commentary, we provide a brief review of recent reports of RPD through the lens of one important empirical issue: the method by which beat perception is measured, and the consequences of method selection for the researcher’s ability to specify which mechanisms are impaired in RPD. This critical reading advocates for the importance of matching measurement tools to the putative neurocognitive mechanisms under study, and reveals the need for effective and specific assessments of the different aspects of rhythm perception and synchronization.

  20. A Facet-Factorial Approach towards the Development and Validation of a Jazz Rhythm Section Performance Rating Scale

    Science.gov (United States)

    Wesolowski, Brian C.

    2017-01-01

    The purpose of this study was to develop a valid and reliable rating scale to assess jazz rhythm sections in the context of jazz big band performance. The research questions that guided this study included: (a) what central factors contribute to the assessment of a jazz rhythm section? (b) what items should be used to describe and assess a jazz…

  1. Human biological rhythm in traditional Chinese medicine

    Directory of Open Access Journals (Sweden)

    Tianxing Zhang

    2016-10-01

    Full Text Available Traditional Chinese medicine (TCM has a comprehensive and thorough understanding of biological rhythm. Biological rhythm is an inherent connotation of “harmony between human and nature”, one of the thoughts in TCM. TCM discusses emphatically circadian rhythm, syzygial rhythm and seasonal rhythm, and particularly circadian and seasonal rhythms. Theories of Yin Yang and Five Elements are the principles and methods, with which TCM understands biological rhythms. Based on theories in TCM, biological rhythm in essence is a continuous variation of the human body state synchronized with natural rhythms, and theories of Yin Yang and Five Elements are both language tools to describe this continuous variation and theoretical tools for its investigation and application. The understandings of biological rhythm in TCM can be applied to etiology, health care, disease control and treatment. Many understandings in TCM have been confirmed by modern research and clinical reports, but there are still some pending issues. TCM is distinguished for its holistic viewpoint on biological rhythms.

  2. Ischemic stroke destabilizes circadian rhythms

    Directory of Open Access Journals (Sweden)

    Borjigin Jimo

    2008-10-01

    Full Text Available Abstract Background The central circadian pacemaker is a remarkably robust regulator of daily rhythmic variations of cardiovascular, endocrine, and neural physiology. Environmental lighting conditions are powerful modulators of circadian rhythms, but regulation of circadian rhythms by disease states is less clear. Here, we examine the effect of ischemic stroke on circadian rhythms in rats using high-resolution pineal microdialysis. Methods Rats were housed in LD 12:12 h conditions and monitored by pineal microdialysis to determine baseline melatonin timing profiles. After demonstration that the circadian expression of melatonin was at steady state, rats were subjected to experimental stroke using two-hour intralumenal filament occlusion of the middle cerebral artery. The animals were returned to their cages, and melatonin monitoring was resumed. The timing of onset, offset, and duration of melatonin secretion were calculated before and after stroke to determine changes in circadian rhythms of melatonin secretion. At the end of the monitoring period, brains were analyzed to determine infarct volume. Results Rats demonstrated immediate shifts in melatonin timing after stroke. We observed a broad range of perturbations in melatonin timing in subsequent days, with rats exhibiting onset/offset patterns which included: advance/advance, advance/delay, delay/advance, and delay/delay. Melatonin rhythms displayed prolonged instability several days after stroke, with a majority of rats showing a day-to-day alternation between advance and delay in melatonin onset and duration. Duration of melatonin secretion changed in response to stroke, and this change was strongly determined by the shift in melatonin onset time. There was no correlation between infarct size and the direction or amplitude of melatonin phase shifting. Conclusion This is the first demonstration that stroke induces immediate changes in the timing of pineal melatonin secretion, indicating

  3. The aesthetic value of the golden ratio and rhythm of the photographs

    Directory of Open Access Journals (Sweden)

    Ivan Budimir

    2015-05-01

    Full Text Available The study analyzes the aesthetic value of rhythm of the photos as opposed to the form in which the rhythm is subjected. With the method of experimental aesthetics, the visual aesthetics experiment is conducted in which the tested quality of the different forms of proportional rhythm due to the shape and length of the interval as a part of the rhythmic matrix. The experimental part consisted of an assessment of visual quality of the 5 photos containing different variations of proportional rate. On all the photographs the rhythm is constituted of cigarettes situated on the surface of the old concrete. Spacing between cigarettes and interval length is successively reduced to accurately defined proportions. In one photograph, the relations between the neighboring intervals are in line with the ratio of the golden section. The experiment involved 32 subjects who had the task of assessing the level of the aesthetic qualities of rhythm on the Likert scale from 1 to 5 where the grades cannot be repeated. Measurement of the quality of a particular form of rhythm is defined as the arithmetic mean score of all respondents. The highest mean is given to the test image with uniform rhythm when the second place is reserved for a photograph whose rhythm is aligned with the golden section. Conducted analysis of repeated measures ANOVA showed that the obtained arithmetic means differ significantly (F = 3.430, p = 0.011 with a significance level of p 0.05.

  4. Capture of irregular satellites at Jupiter

    International Nuclear Information System (INIS)

    Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio

    2014-01-01

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10 –8 . This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.

  5. Temporal interactions between cortical rhythms

    Directory of Open Access Journals (Sweden)

    Anita K Roopun

    2008-12-01

    Full Text Available Multiple local neuronal circuits support different, discrete frequencies of network rhythm in neocortex. Relationships between different frequencies correspond to mechanisms designed to minimise interference, couple activity via stable phase interactions, and control the amplitude of one frequency relative to the phase of another. These mechanisms are proposed to form a framework for spectral information processing. Individual local circuits can also transform their frequency through changes in intrinsic neuronal properties and interactions with other oscillating microcircuits. Here we discuss a frequency transformation in which activity in two coactive local circuits may combine sequentially to generate a third frequency whose period is the concatenation sum of the original two. With such an interaction, the intrinsic periodicity in each component local circuit is preserved – alternate, single periods of each original rhythm form one period of a new frequency - suggesting a robust mechanism for combining information processed on multiple concurrent spatiotemporal scales.

  6. Circadian Rhythm Control: Neurophysiological Investigations

    Science.gov (United States)

    Glotzbach, S. F.

    1985-01-01

    The suprachiasmatic nucleus (SCN) was implicated as a primary component in central nervous system mechanisms governing circadian rhythms. Disruption of the normal synchronization of temperature, activity, and other rhythms is detrimental to health. Sleep wake disorders, decreases in vigilance and performance, and certain affective disorders may result from or be exacerbated by such desynchronization. To study the basic neurophysiological mechanisms involved in entrainment of circadian systems by the environment, Parylene-coated, etched microwire electrode bundles were used to record extracellular action potentials from the small somata of the SCN and neighboring hypothalamic nuclei in unanesthetized, behaving animals. Male Wistar rats were anesthetized and chronically prepared with EEG ane EMG electrodes in addition to a moveable microdrive assembly. The majority of cells had firing rates 10 Hz and distinct populations of cells which had either the highest firing rate or lowest firing rate during sleep were seen.

  7. Chaos control applied to cardiac rhythms represented by ECG signals

    International Nuclear Information System (INIS)

    Borem Ferreira, Bianca; Amorim Savi, Marcelo; Souza de Paula, Aline

    2014-01-01

    The control of irregular or chaotic heartbeats is a key issue in cardiology. In this regard, chaos control techniques represent a good alternative since they suggest treatments different from those traditionally used. This paper deals with the application of the extended time-delayed feedback control method to stabilize pathological chaotic heart rhythms. Electrocardiogram (ECG) signals are employed to represent the cardiovascular behavior. A mathematical model is employed to generate ECG signals using three modified Van der Pol oscillators connected with time delay couplings. This model provides results that qualitatively capture the general behavior of the heart. Controlled ECG signals show the ability of the strategy either to control or to suppress the chaotic heart dynamics generating less-critical behaviors. (paper)

  8. [Effect of Earth magnetic field on circadian rhythm of total antioxidant capacity of human saliva in the North].

    Science.gov (United States)

    Borisenkov, M F

    2007-01-01

    In the inhabitants of the North during increase of geomagnetic activity and during magnetic calm the decrease of amplitude of circadian rhythm of total antioxidant capacity of saliva is observed. The most favorable conditions to display the circadian rhythm are observed at Kp from 0,5 up to 2. The long residing in the North is connected to influence of irregularly varying geomagnetic activity causing disturbance of function of circadian and antioxidant systems that, probably, is one of the reasons of acceleration of process of aging at northerner and of higher risk of occurrence in them the age associated diseases.

  9. Biological Rhythms in the Skin

    Directory of Open Access Journals (Sweden)

    Mary S. Matsui

    2016-05-01

    Full Text Available Circadian rhythms, ≈24 h oscillations in behavior and physiology, are reflected in all cells of the body and function to optimize cellular functions and meet environmental challenges associated with the solar day. This multi-oscillatory network is entrained by the master pacemaker located in the suprachiasmatic nucleus (SCN of the hypothalamus, which directs an organism’s rhythmic expression of physiological functions and behavior via a hierarchical system. This system has been highly conserved throughout evolution and uses transcriptional–translational autoregulatory loops. This master clock, following environmental cues, regulates an organism’s sleep pattern, body temperature, cardiac activity and blood pressure, hormone secretion, oxygen consumption and metabolic rate. Mammalian peripheral clocks and clock gene expression have recently been discovered and are present in all nucleated cells in our body. Like other essential organ of the body, the skin also has cycles that are informed by this master regulator. In addition, skin cells have peripheral clocks that can function autonomously. First described in 2000 for skin, this review summarizes some important aspects of a rapidly growing body of research in circadian and ultradian (an oscillation that repeats multiple times during a 24 h period cutaneous rhythms, including clock mechanisms, functional manifestations, and stimuli that entrain or disrupt normal cycling. Some specific relationships between disrupted clock signaling and consequences to skin health are discussed in more depth in the other invited articles in this IJMS issue on Sleep, Circadian Rhythm and Skin.

  10. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  11. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  12. Bleeding risk assessment and management in atrial fibrillation patients. Executive Summary of a Position Document from the European Heart Rhythm Association [EHRA], endorsed by the European Society of Cardiology [ESC] Working Group on Thrombosis.

    Science.gov (United States)

    Lip, Gregory Y H; Andreotti, Felicita; Fauchier, Laurent; Huber, Kurt; Hylek, Elaine; Knight, Eve; Lane, Deirdre; Levi, Marcel; Marín, Francisco; Palareti, Gualtiero; Kirchhof, Paulus

    2011-12-01

    In this executive summary of a Consensus Document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in atrial fibrillation (AF) patients. The main aim of the document was to summarise 'best practice' in dealing with bleeding risk in AF patients when approaching antithrombotic therapy, by addressing the epidemiology and size of the problem, and review established bleeding risk factors. We also summarise definitions of bleeding in the published literature. Patient values and preferences balancing the risk of bleeding against thromboembolism as well as the prognostic implications of bleeding are reviewed. We also provide an overview of published bleeding risk stratification and bleeding risk schema. Brief discussion of special situations (e.g. periablation, peri-devices such as implantable cardioverter defibrillators [ICD] or pacemakers, presentation with acute coronary syndromes and/or requiring percutanous coronary interventions/stents and bridging therapy) is made, as well as a discussion of the prevention of bleeds and managing bleeding complications. Finally, this document puts forwards consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

  13. Examining U.S. Irregular Warfare Doctrine

    National Research Council Canada - National Science Library

    Kimbrough, IV, James M

    2008-01-01

    ... of insurgency and terrorism. In response to the associated strategic challenges, a growing debate occurred among military historians, strategists, and leaders about the proper principles necessary for contemporary irregular...

  14. Locating irregularly shaped clusters of infection intensity

    Directory of Open Access Journals (Sweden)

    Niko Yiannakoulias

    2010-05-01

    Full Text Available Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until recently, cluster detection methods were limited in their ability to detect irregular spatial patterns, and limited to finding clusters that were roughly circular in shape. This approach has less power to detect irregularly-shaped, yet important spatial anomalies, particularly at high spatial resolutions. We employ a new method of finding irregularly-shaped spatial clusters at micro-geographical scales using both simulated and real data on Schistosoma mansoni and hookworm infection intensities. This method, which we refer to as the “greedy growth scan”, is a modification of the spatial scan method for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the “greedy growth scan” is a suitable method for exploratory geographical analysis of infection intensity data when irregular shapes are suspected, especially at micro-geographical scales.

  15. Regularities and irregularities in order flow data

    Science.gov (United States)

    Theissen, Martin; Krause, Sebastian M.; Guhr, Thomas

    2017-11-01

    We identify and analyze statistical regularities and irregularities in the recent order flow of different NASDAQ stocks, focusing on the positions where orders are placed in the order book. This includes limit orders being placed outside of the spread, inside the spread and (effective) market orders. Based on the pairwise comparison of the order flow of different stocks, we perform a clustering of stocks into groups with similar behavior. This is useful to assess systemic aspects of stock price dynamics. We find that limit order placement inside the spread is strongly determined by the dynamics of the spread size. Most orders, however, arrive outside of the spread. While for some stocks order placement on or next to the quotes is dominating, deeper price levels are more important for other stocks. As market orders are usually adjusted to the quote volume, the impact of market orders depends on the order book structure, which we find to be quite diverse among the analyzed stocks as a result of the way limit order placement takes place.

  16. Using Little's Irregularity Index in orthodontics: outdated and inaccurate?

    LENUS (Irish Health Repository)

    Macauley, Donal

    2012-12-01

    Little\\'s Irregularity Index (LII) was devised to objectively score mandibular incisor alignment for epidemiological studies but has been extended to assess the relative performance of orthodontic brackets, retainer or treatment modalities. Our aim was to examine the repeatability and precision of LII measurements of four independent examiners on the maxillary arch of orthodontic patients. The hypothesis was that the reproducibility of individual contact point displacement measurements, used to calculate the LII score, are inappropriate.

  17. Acquisition of speech rhythm in first language.

    Science.gov (United States)

    Polyanskaya, Leona; Ordin, Mikhail

    2015-09-01

    Analysis of English rhythm in speech produced by children and adults revealed that speech rhythm becomes increasingly more stress-timed as language acquisition progresses. Children reach the adult-like target by 11 to 12 years. The employed speech elicitation paradigm ensured that the sentences produced by adults and children at different ages were comparable in terms of lexical content, segmental composition, and phonotactic complexity. Detected differences between child and adult rhythm and between rhythm in child speech at various ages cannot be attributed to acquisition of phonotactic language features or vocabulary, and indicate the development of language-specific phonetic timing in the course of acquisition.

  18. Factors influencing circadian rhythms in acetaminophen lethality.

    Science.gov (United States)

    Schnell, R C; Bozigian, H P; Davies, M H; Merrick, B A; Park, K S; McMillan, D A

    1984-01-01

    Experiments were conducted to examine the effects of changes in lighting schedules and food consumption on circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice. Under a normal lighting schedule (light: 06.00-18.00 h), male mice exhibited a circadian rhythm in acetaminophen lethality (peak: 18.00 h; nadir: 06.00, 10.00 h) and an inverse rhythm in hepatic glutathione concentrations (peak: 06.00, 10.00 h; nadir: 18.00 h). Under a reversed lighting schedule (light: 18.00-06.00 h) the glutathione rhythm was reversed and the rhythm in acetaminophen lethality was altered showing greater sensitivity to the drug. Under continuous light, there was a shift in the acetaminophen lethality and the hepatic glutathione rhythms. Under continuous dark, both rhythms were abolished. Under a normal lighting regimen, hepatic glutathione levels were closely correlated with food consumption; i.e., both were increased during the dark phase and decreased during the light phase. Fasting the mice for 12 h abolished the rhythms in acetaminophen lethality and hepatic glutathione levels; moreover, the lethality was increased and the hepatic glutathione levels were decreased. These experiments show that both lighting schedules and feeding can alter the circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice.

  19. Circadian Rhythm Shapes the Gut Microbiota Affecting Host Radiosensitivity.

    Science.gov (United States)

    Cui, Ming; Xiao, Huiwen; Luo, Dan; Zhang, Xin; Zhao, Shuyi; Zheng, Qisheng; Li, Yuan; Zhao, Yu; Dong, Jiali; Li, Hang; Wang, Haichao; Fan, Saijun

    2016-10-26

    Modern lifestyles, such as shift work, nocturnal social activities, and jet lag, disturb the circadian rhythm. The interaction between mammals and the co-evolved intestinal microbiota modulates host physiopathological processes. Radiotherapy is a cornerstone of modern management of malignancies; however, it was previously unknown whether circadian rhythm disorder impairs prognosis after radiotherapy. To investigate the effect of circadian rhythm on radiotherapy, C57BL/6 mice were housed in different dark/light cycles, and their intestinal bacterial compositions were compared using high throughput sequencing. The survival rate, body weight, and food intake of mice in diverse cohorts were measured following irradiation exposure. Finally, the enteric bacterial composition of irradiated mice that experienced different dark/light cycles was assessed using 16S RNA sequencing. Intriguingly, mice housed in aberrant light cycles harbored a reduction of observed intestinal bacterial species and shifts of gut bacterial composition compared with those of the mice kept under 12 h dark/12 h light cycles, resulting in a decrease of host radioresistance. Moreover, the alteration of enteric bacterial composition of mice in different groups was dissimilar. Our findings provide novel insights into the effects of biological clocks on the gut bacterial composition, and underpin that the circadian rhythm influences the prognosis of patients after radiotherapy in a preclinical setting.

  20. GENERATION OF IRREGULAR HEXAGONAL MESHES

    Directory of Open Access Journals (Sweden)

    Vlasov Aleksandr Nikolaevich

    2012-07-01

    Decomposition is performed in a constructive way and, as option, it involves meshless representation. Further, this mapping method is used to generate the calculation mesh. In this paper, the authors analyze different cases of mapping onto simply connected and bi-connected canonical domains. They represent forward and backward mapping techniques. Their potential application for generation of nonuniform meshes within the framework of the asymptotic homogenization theory is also performed to assess and project effective characteristics of heterogeneous materials (composites.

  1. Detecting chaos in irregularly sampled time series.

    Science.gov (United States)

    Kulp, C W

    2013-09-01

    Recently, Wiebe and Virgin [Chaos 22, 013136 (2012)] developed an algorithm which detects chaos by analyzing a time series' power spectrum which is computed using the Discrete Fourier Transform (DFT). Their algorithm, like other time series characterization algorithms, requires that the time series be regularly sampled. Real-world data, however, are often irregularly sampled, thus, making the detection of chaotic behavior difficult or impossible with those methods. In this paper, a characterization algorithm is presented, which effectively detects chaos in irregularly sampled time series. The work presented here is a modification of Wiebe and Virgin's algorithm and uses the Lomb-Scargle Periodogram (LSP) to compute a series' power spectrum instead of the DFT. The DFT is not appropriate for irregularly sampled time series. However, the LSP is capable of computing the frequency content of irregularly sampled data. Furthermore, a new method of analyzing the power spectrum is developed, which can be useful for differentiating between chaotic and non-chaotic behavior. The new characterization algorithm is successfully applied to irregularly sampled data generated by a model as well as data consisting of observations of variable stars.

  2. Analysis of Handwriting based on Rhythm Perception

    Science.gov (United States)

    Saito, Kazuya; Uchida, Masafumi; Nozawa, Akio

    Humanity fluctuation was reported in some fields. In handwriting process, fluctuation appears on handwriting-velocity. In this report, we focused attention on human rhythm perception and analyzed fluctuation in handwriting process. As a result, 1/f noise related to rhythm perception and features may caused by Kahneman's capacity model were measured on handwriting process.

  3. Development of cortisol circadian rhythm in infancy.

    NARCIS (Netherlands)

    Weerth, C. de; Zijl, R.H.

    2003-01-01

    BACKGROUND AND AIMS: Cortisol is the final product of the hypothalamus-pituitary-adrenal (HPA) axis. It is secreted in a pulsatile fashion that displays a circadian rhythm. Infants are born without a circadian rhythm in cortisol and they acquire it during their first year of life. Studies do not

  4. Irregular menstruation according to occupational status.

    Science.gov (United States)

    Kwak, Yeunhee; Kim, Yoonjung

    2017-07-06

    This cross-sectional study explored associations of irregular menstruation with occupational characteristics, using secondary analyses of data from 4,731 women aged 19-54 years, collected from a nationally representative sample, the Korea National Health and Nutrition Examination Survey-V during 2010-2012. The associations between irregular menstruation and occupation were explored using multiple logistic regression. Compared to non-manual workers, service/sales workers had a greater odds of irregular menstruation (adjusted odds ratio [aOR]: 1.44; 95percent confidence interval [CI]: 1.04-1.99) as did manual workers and unemployed women (aOR: 1.56; 95percent CI: 1.10-2.22, aOR: 1.46; 95percent CI: 1.14-1.89, respectively). Compared to regular workers, temporary workers and unemployed women had aORs of 1.52 (95percent CI: 1.08-2.13) and 1.33 (95percent CI: 1.05-1.69), respectively. Also, when compared to full-time workers, part-time workers and unemployed women had greater odds of irregular menstruation (aOR: 1.41; 95percent CI: 1.00-2.00 and aOR: 1.29; 95percent CI: 1.03-1.63, respectively). Furthermore, compared to daytime workers, shift workers and unemployed women had greater odds irregular menstruation (aOR: 1.39; 95percent CI: 1.03-1.88 and aOR: 1.28; 95percent CI: 1.04-1.59, respectively). Women with these occupational characteristics should be screened for early diagnosis and intervention for irregular menstruation.

  5. Measurement of the occipital alpha rhythm and temporal tau rhythm by using magnetoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. E.; Gohel, Bakul; Kim, K.; Kwon, H.; An, Kyung Min [Center for Biosignals, Korea Research Institute of Standards and Science(KRISS), Daejeon (Korea, Republic of)

    2015-12-15

    Developing Magnetoencephalography (MEG) based on Superconducting Quantum Interference Device (SQUID) facilitates to observe the human brain functions in non-invasively and high temporal and high spatial resolution. By using this MEG, we studied alpha rhythm (8-13 Hz) that is one of the most predominant spontaneous rhythm in human brain. The 8–13 Hz rhythm is observed in several sensory region in the brain. In visual related region of occipital, we call to alpha rhythm, and auditory related region of temporal call to tau rhythm, sensorimotor related region of parietal call to mu rhythm. These rhythms are decreased in task related region and increased in task irrelevant regions. This means that these rhythms play a pivotal role of inhibition in task irrelevant region. It may be helpful to attention to the task. In several literature about the alpha-band inhibition in multi-sensory modality experiment, they observed this effect in the occipital and somatosensory region. In this study, we hypothesized that we can also observe the alpha-band inhibition in the auditory cortex, mediated by the tau rhythm. Before that, we first investigated the existence of the alpha and tau rhythm in occipital and temporal region, respectively. To see these rhythms, we applied the visual and auditory stimulation, in turns, suppressed in task relevant regions, respectively.

  6. Measurement of the occipital alpha rhythm and temporal tau rhythm by using magnetoencephalography

    International Nuclear Information System (INIS)

    Kim, J. E.; Gohel, Bakul; Kim, K.; Kwon, H.; An, Kyung Min

    2015-01-01

    Developing Magnetoencephalography (MEG) based on Superconducting Quantum Interference Device (SQUID) facilitates to observe the human brain functions in non-invasively and high temporal and high spatial resolution. By using this MEG, we studied alpha rhythm (8-13 Hz) that is one of the most predominant spontaneous rhythm in human brain. The 8–13 Hz rhythm is observed in several sensory region in the brain. In visual related region of occipital, we call to alpha rhythm, and auditory related region of temporal call to tau rhythm, sensorimotor related region of parietal call to mu rhythm. These rhythms are decreased in task related region and increased in task irrelevant regions. This means that these rhythms play a pivotal role of inhibition in task irrelevant region. It may be helpful to attention to the task. In several literature about the alpha-band inhibition in multi-sensory modality experiment, they observed this effect in the occipital and somatosensory region. In this study, we hypothesized that we can also observe the alpha-band inhibition in the auditory cortex, mediated by the tau rhythm. Before that, we first investigated the existence of the alpha and tau rhythm in occipital and temporal region, respectively. To see these rhythms, we applied the visual and auditory stimulation, in turns, suppressed in task relevant regions, respectively

  7. Advances in electron dosimetry of irregular fields

    International Nuclear Information System (INIS)

    Mendez V, J.

    1998-01-01

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm 2 with percentile error less than 1 % . (Author)

  8. New Model for Ionospheric Irregularities at Mars

    Science.gov (United States)

    Keskinen, M. J.

    2018-03-01

    A new model for ionospheric irregularities at Mars is presented. It is shown that wind-driven currents in the dynamo region of the Martian ionosphere can be unstable to the electromagnetic gradient drift instability. This plasma instability can generate ionospheric density and magnetic field irregularities with scale sizes of approximately 15-20 km down to a few kilometers. We show that the instability-driven magnetic field fluctuation amplitudes relative to background are correlated with the ionospheric density fluctuation amplitudes relative to background. Our results can explain recent observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the Martian ionosphere dynamo region.

  9. High energy model for irregular absorbing particles

    International Nuclear Information System (INIS)

    Chiappetta, Pierre.

    1979-05-01

    In the framework of a high energy formulation of relativistic quantum scattering a model is presented which describes the scattering functions and polarization of irregular absorbing particles, whose dimensions are greater than the incident wavelength. More precisely in the forward direction an amplitude parametrization of eikonal type is defined which generalizes the usual diffraction theory, and in the backward direction a reflective model is used including a shadow function. The model predictions are in good agreement with the scattering measurements off irregular compact and fluffy particles performed by Zerull, Giese and Weiss (1977)

  10. Walking to the beat of different drums: Practical implications for the use of acoustic rhythms in gait rehabilitation

    NARCIS (Netherlands)

    Roerdink, M.; Bank, P.J.M.; Peper, C.E.; Beek, P.J.

    2011-01-01

    Acoustic rhythms are frequently used in gait rehabilitation, with positive instantaneous and prolonged transfer effects on various gait characteristics. The gait modifying ability of acoustic rhythms depends on how well gait is tied to the beat, which can be assessed with measures of relative timing

  11. [The influence of interfered circadian rhythm on pregnancy and neonatal rats].

    Science.gov (United States)

    Chen, Wen-Jun; Sheng, Wen-Jie; Guo, Yin-Hua; Tan, Yong

    2015-10-25

    The aim of this study was to observe the influence of interfered circadian rhythm on pregnancy of rats and growth of neonatal rats, and to explore the relationship between the interfered circadian rhythm and the changes of melatonin and progesterone. Continuous light was used to inhibit melatonin secretion and therefore the interfered circadian rhythm animal model was obtained. The influence of interfered circadian rhythm on delivery of pregnant rats was observed. Serum was collected from rats during different stages of pregnancy to measure the concentrations of melatonin and progesterone. In order to observe the embryo resorption rate, half of pregnant rats were randomly selected to undergo a laparotomy, and the remainder was used to observe delivery and assess the growth of neonatal rats after delivery. The results showed that the interfered circadian rhythm induced adverse effects on pregnancy outcomes, including an increase of embryo resorption rate and a decrease in the number of live births; inhibited the secretion of melatonin along with decreased serum progesterone level; prolonged the stage of labor, but not the duration of pregnancy; and disturbed the fetal intrauterine growth and the growth of neonatal rats. The results suggest that interfered circadian rhythm condition made by continuous light could make adverse effects on both pregnant rats and neonatal rats. The results of our study may provide a way to modulate pregnant women's circadian rhythm and a possibility of application of melatonin on pregnant women.

  12. Evaluation of irregular menses in perimenarcheal girls: a pilot study.

    Science.gov (United States)

    Browner-Elhanan, Karen J; Epstein, Jonathan; Alderman, Elizabeth M

    2003-12-01

    Acyclic vaginal bleeding in girls within three years of menarche is most commonly attributed to an immature hypothalamic-pituitary-ovarian axis. Assuming this diagnosis may preclude the practitioner from performing more definitive studies and thereby diagnosing other, treatable causes of menstrual irregularities. A retrospective chart review of 178 girls presenting to an inner-city hospital-based adolescent clinic within three years of menarche was performed. Personal and family medical and menarcheal history was assessed, and findings on physical and laboratory examination performed were evaluated. Of the 178 girls still perimenarcheal at presentation, 47 were the focus of this study. Of these, 39 had no significant findings on physical examination, while 3 had signs of functional ovarian hyperandrogenism (FOH) including obesity, hirsutism, and moderate acne with corresponding LH/FSH ratios>3, although pelvic ultrasound examination revealed normal ovaries. Four of the 39 patients with normal physical exams had LH/FSH testing done, and 1 of the 4 had an abnormal LH/FSH ratio, indicating possible FOH. Two of the 47 patients were pregnant. Other laboratory abnormalities included microcytic, hypochromic anemia in patients, and an elevated Erythrocyte Sedimentation Rate in a patient later diagnosed with a rheumatologic disorder. Those perimenarcheal girls presenting with irregular menses and findings including obesity, acne, or pallor, were likely to have treatable causes of menstrual irregularities. In one of the four girls with a normal physical examination, hormonal testing indicated possible FOH, thus suggesting that hormonal evaluation of perimenarcheal girls with menstrual irregularities may be justified, as it may reveal previously unsuspected pathology.

  13. Recognition memory for vibrotactile rhythms: an fMRI study in blind and sighted individuals.

    Science.gov (United States)

    Sinclair, Robert J; Dixit, Sachin; Burton, Harold

    2011-01-01

    Calcarine sulcal cortex possibly contributes to semantic recognition memory in early blind (EB). We assessed a recognition memory role using vibrotactile rhythms and a retrieval success paradigm involving learned "old" and "new" rhythms in EB and sighted. EB showed no activation differences in occipital cortex indicating retrieval success but replicated findings of somatosensory processing. Both groups showed retrieval success in primary somatosensory, precuneus, and orbitofrontal cortex. The S1 activity might indicate generic sensory memory processes.

  14. Synchronizing data from irregularly sampled sensors

    Science.gov (United States)

    Uluyol, Onder

    2017-07-11

    A system and method include receiving a set of sampled measurements for each of multiple sensors, wherein the sampled measurements are at irregular intervals or different rates, re-sampling the sampled measurements of each of the multiple sensors at a higher rate than one of the sensor's set of sampled measurements, and synchronizing the sampled measurements of each of the multiple sensors.

  15. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal

    1990-01-01

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

  16. Internal Medicine Physicians’ Perceptions Regarding Rate versus Rhythm Control for Atrial Fibrillation

    Science.gov (United States)

    McCabe, James M.; Johnson, Colleen J; Marcus, Gregory M

    2011-01-01

    Atrial fibrillation (AF) is often managed by general internal medicine physicians. Available data suggest that guidelines regarding AF management are often not followed, but the reasons for this remain unknown. We sought to assess the knowledge and beliefs of internists regarding strategies to treat AF. We conducted a national electronic survey of internal medicine physicians regarding their perceptions of optimal AF management, with an emphasis on the rationale for choosing a rhythm or rate control strategy. One hundred and forty-eight physicians from 36 different states responded (representing at least 19% of unique e-mails opened). Half of the respondents reported managing their AF patients independently without referral to a cardiologist. Seventy-three percent of participants believe a rhythm control strategy conveys a decreased stroke risk, 64% believe there is a mortality benefit to rhythm control, and 55% think that it would help avoid long term anticoagulation. Comparing those who prefer a rhythm control strategy to everyone else, those who favor rhythm control statistically significantly more often believe that rhythm control reduces the risk for stroke (96% versus 67%, p=0.009) and that rhythm control allows for the discontinuation of anticoagulation therapy (76% versus 49%, p=0.045). In conclusion, contrary to available data in clinical trials and recent guidelines regarding the rationale for choosing a rhythm control strategy in treating AF, the majority of study participants believe that rhythm control decreases stroke risk, decreases mortality, and allows for discontinuation of anticoagulation therapy. These prevalent misconceptions may substantially contribute to guideline non-adherence. PMID:19195516

  17. Speech-like rhythm in a voiced and voiceless orangutan call.

    Directory of Open Access Journals (Sweden)

    Adriano R Lameira

    Full Text Available The evolutionary origins of speech remain obscure. Recently, it was proposed that speech derived from monkey facial signals which exhibit a speech-like rhythm of ∼5 open-close lip cycles per second. In monkeys, these signals may also be vocalized, offering a plausible evolutionary stepping stone towards speech. Three essential predictions remain, however, to be tested to assess this hypothesis' validity; (i Great apes, our closest relatives, should likewise produce 5Hz-rhythm signals, (ii speech-like rhythm should involve calls articulatorily similar to consonants and vowels given that speech rhythm is the direct product of stringing together these two basic elements, and (iii speech-like rhythm should be experience-based. Via cinematic analyses we demonstrate that an ex-entertainment orangutan produces two calls at a speech-like rhythm, coined "clicks" and "faux-speech." Like voiceless consonants, clicks required no vocal fold action, but did involve independent manoeuvring over lips and tongue. In parallel to vowels, faux-speech showed harmonic and formant modulations, implying vocal fold and supralaryngeal action. This rhythm was several times faster than orangutan chewing rates, as observed in monkeys and humans. Critically, this rhythm was seven-fold faster, and contextually distinct, than any other known rhythmic calls described to date in the largest database of the orangutan repertoire ever assembled. The first two predictions advanced by this study are validated and, based on parsimony and exclusion of potential alternative explanations, initial support is given to the third prediction. Irrespectively of the putative origins of these calls and underlying mechanisms, our findings demonstrate irrevocably that great apes are not respiratorily, articulatorilly, or neurologically constrained for the production of consonant- and vowel-like calls at speech rhythm. Orangutan clicks and faux-speech confirm the importance of rhythmic speech

  18. Fluctuation of biological rhythm in finger tapping

    Science.gov (United States)

    Yoshinaga, H.; Miyazima, S.; Mitake, S.

    2000-06-01

    By analyzing biological rhythms obtained from finger tapping, we have investigated the differences of two biological rhythms between healthy and handicapped persons caused by Parkinson, brain infraction, car accident and so on. In this study, we have observed the motion of handedness of all subjects and obtained a slope a which characterizes a power-law relation between frequency and amplitude of finger-tapping rhythm. From our results, we have estimated that the slope a=0.06 is a rough criterion in order to distinguish healthy and handicapped persons.

  19. Fitting Irregular Shape Figures into Irregular Shape Areas for the Nesting Problem in the Leather Industry

    Directory of Open Access Journals (Sweden)

    Guevara-Palma Luis

    2015-01-01

    Full Text Available The nesting problem of irregular shapes within irregular areas has been studied from several approaches due to their application in different industries. The particular case of cutting leather involves several restrictions that add complexity to this problem, it is necessary to generate products that comply with the quality required by customers This paper presents a methodology for the accommodation of irregular shapes in an irregular area (leather considering the constraints set by the footwear industry, and the results of this methodology when applied by a computer system. The scope of the system is to develop a working prototype that operates under the guidelines of a commercial production line of a sponsor company. Preliminary results got a reduction of 70% of processing time and improvement of 5% to 7% of the area usage when compared with manual accommodation.

  20. Sleep and circadian rhythm disturbance in bipolar disorder.

    Science.gov (United States)

    Bradley, A J; Webb-Mitchell, R; Hazu, A; Slater, N; Middleton, B; Gallagher, P; McAllister-Williams, H; Anderson, K N

    2017-07-01

    Subjective reports of insomnia and hypersomnia are common in bipolar disorder (BD). It is unclear to what extent these relate to underlying circadian rhythm disturbance (CRD). In this study we aimed to objectively assess sleep and circadian rhythm in a cohort of patients with BD compared to matched controls. Forty-six patients with BD and 42 controls had comprehensive sleep/circadian rhythm assessment with respiratory sleep studies, prolonged accelerometry over 3 weeks, sleep questionnaires and diaries, melatonin levels, alongside mood, psychosocial functioning and quality of life (QoL) questionnaires. Twenty-three (50%) patients with BD had abnormal sleep, of whom 12 (52%) had CRD and 29% had obstructive sleep apnoea. Patients with abnormal sleep had lower 24-h melatonin secretion compared to controls and patients with normal sleep. Abnormal sleep/CRD in BD was associated with impaired functioning and worse QoL. BD is associated with high rates of abnormal sleep and CRD. The association between these disorders, mood and functioning, and the direction of causality, warrants further investigation.

  1. Circadian Rhythm Management System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The value of measuring sleep-wake cycles is significantly enhanced by measuring other physiological signals that depend on circadian rhythms (such as heart rate and...

  2. Generating Performance Models for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

    2017-05-30

    Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

  3. Long wavelength irregularities in the equatorial electrojet

    OpenAIRE

    Kudeki, E.; Farley, D. T.; Fejer, Bela G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach...

  4. Improving Transactional Memory Performance for Irregular Applications

    OpenAIRE

    Pedrero, Manuel; Gutiérrez, Eladio; Romero, Sergio; Plata, Óscar

    2015-01-01

    Transactional memory (TM) offers optimistic concurrency support in modern multicore archi- tectures, helping the programmers to extract parallelism in irregular applications when data dependence information is not available before runtime. In fact, recent research focus on ex- ploiting thread-level parallelism using TM approaches. However, the proposed techniques are of general use, valid for any type of application. This work presents ReduxSTM, a software TM system specially d...

  5. Star formation histories of irregular galaxies

    International Nuclear Information System (INIS)

    Gallagher, J.S. III; Hunter, D.A.; Tutukov, A.V.

    1984-01-01

    We explore the star formation histories of a selection of irregular and spiral galaxies by using three parameters that sample the star formation rate (SFR) at different epochs: (1) the mass of a galaxy in the form of stars measures the SFR integrated over a galaxy's lifetime; (2) the blue luminosity is dominated primarily by stars formed over the past few billion years; and (3) Lyman continuum photon fluxes derived from Hα luminosities give the current ( 8 yr) SFR

  6. Parallel Computing Strategies for Irregular Algorithms

    Science.gov (United States)

    Biswas, Rupak; Oliker, Leonid; Shan, Hongzhang; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Parallel computing promises several orders of magnitude increase in our ability to solve realistic computationally-intensive problems, but relies on their efficient mapping and execution on large-scale multiprocessor architectures. Unfortunately, many important applications are irregular and dynamic in nature, making their effective parallel implementation a daunting task. Moreover, with the proliferation of parallel architectures and programming paradigms, the typical scientist is faced with a plethora of questions that must be answered in order to obtain an acceptable parallel implementation of the solution algorithm. In this paper, we consider three representative irregular applications: unstructured remeshing, sparse matrix computations, and N-body problems, and parallelize them using various popular programming paradigms on a wide spectrum of computer platforms ranging from state-of-the-art supercomputers to PC clusters. We present the underlying problems, the solution algorithms, and the parallel implementation strategies. Smart load-balancing, partitioning, and ordering techniques are used to enhance parallel performance. Overall results demonstrate the complexity of efficiently parallelizing irregular algorithms.

  7. Dysrhythmia: a specific congenital rhythm perception deficit

    Directory of Open Access Journals (Sweden)

    Jacques eLaunay

    2014-02-01

    Full Text Available Why do some people have problems ‘feeling the beat’? Here we investigate participants with congenital impairments in musical rhythm perception and production. A web-based version of the Montreal Battery of Evaluation of Amusia (MBEA was used to screen for difficulties with rhythmic processing in a large sample and we identified three ‘dysrhythmic’ individuals who scored below cut-off for the rhythm subtest, but not the pitch-based subtests. Follow-up testing in the laboratory was conducted to characterize the nature of both rhythm perception and production deficits in these dysrhythmic individuals. We found that they differed from control participants when required to synchronize their tapping to an external stimulus with a metrical pulse, but not when required to tap spontaneously (with no external stimulus or to tap in time to an isochronous stimulus. Dysrhythmics exhibited a general tendency to tap at half the expected tempo when asked to synchronize to the beat of strongly metrical rhythms. These results suggest that the individuals studied here did not have motor production problems, but suffer from a selective rhythm perception deficit that influences the ability to entrain to metrical rhythms.

  8. Right- and left-brain hemisphere. Rhythm in reaction time to light signals is task-load-dependent: age, gender, and handgrip strength rhythm comparisons.

    Science.gov (United States)

    Reinberg, Alain; Bicakova-Rocher, Alena; Mechkouri, Mohamed; Ashkenazi, Israel

    2002-11-01

    In healthy mature subjects simple reaction time (SRT) to a single light signal (an easy task) is associated with a prominent rhythm with tau = 24 h of dominant (DH) as well as nondominant (NDH) hand performance, while three-choice reaction time (CRT), a complex task, is associated with tau = 24 h of the DH but tau gender on the difference in tau of the NDH and DH, as it relates to the corresponding cortical hemisphere of the brain, in comparison to the rhythm in handgrip strength. Healthy subjects, 9 (5 M and 4 F) adolescents 10-16 yr of age and 15 (8 M and 7 F) adults 18-67 yr of age, active between 08:00 +/- 1 h and 23:00 +/- 1:30 h and free of alcohol, tobacco, and drug consumption volunteered. Data were gathered longitudinally at home and work 4-7 times daily for 11-20 d. At each test time the following variables were assessed: grip strength of both hands (Dynamometer: Colin-Gentile, Paris, France); single reaction time to a yellow signal (SRT); and CRT to randomized yellow, red, or green signal series with varying instruction from test to test (Psycholog-24: Biophyderm, France). Rhythms in the performance in SRT, CRT, and handgrip strength of both DH and NDH were explored. The sleep-wake rhythm was assessed by sleep-logs, and in a subset of 14 subjects it was also assessed by wrist actigraphy (Mini-Motionlogger: AMI, Ardsley NY). Exploration of the prominent period tau of time series was achieved by a special power spectra analysis for unequally spaced data. Cosinor analysis was used to quantify the rhythm amplitude A and rhythm-adjusted mean M of the power spectral analysis determined trial tau. A 24h sleep-wake rhythm was detected in almost all cases. In adults, a prominent tau of 24 h characterized the performance of the easy task by both the DH and NDH. In adults a prominent tau of 24 h was also detected in the complex CRT task performed by the DH, but for the NDH the tau was gender-related but was age-related since it was seldom observed in adolescent

  9. The role of feeding rhythm, adrenal hormones and neuronal inputs in synchronizing daily clock gene rhythms in the liver.

    Science.gov (United States)

    Su, Yan; Cailotto, Cathy; Foppen, Ewout; Jansen, Remi; Zhang, Zhi; Buijs, Ruud; Fliers, Eric; Kalsbeek, Andries

    2016-02-15

    The master clock in the hypothalamic suprachiasmatic nucleus (SCN) is assumed to distribute rhythmic information to the periphery via neural, humoral and/or behavioral connections. Until now, feeding, corticosterone and neural inputs are considered important signals for synchronizing daily rhythms in the liver. In this study, we investigated the necessity of neural inputs as well as of the feeding and adrenal hormone rhythms for maintaining daily hepatic clock gene rhythms. Clock genes kept their daily rhythm when only one of these three signals was disrupted, or when we disrupted hepatic neuronal inputs together with the adrenal hormone rhythm or with the daily feeding rhythm. However, all clock genes studied lost their daily expression rhythm after simultaneous disruption of the feeding and adrenal hormone rhythm. These data indicate that either a daily rhythm of feeding or adrenal hormones should be present to synchronize clock gene rhythms in the liver with the SCN. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. The Impact of Irregular Warfare on the US Army

    National Research Council Canada - National Science Library

    McDonald, III, Roger L

    2006-01-01

    Although the U.S. Army has yet to clearly define irregular warfare, it is imperative that the Army take near-term action to enhance the ability of Soldiers and units to operate effectively in an irregular warfare environment...

  11. State reconstruction and irregular wavefunctions for the hydrogen atom

    Science.gov (United States)

    Krähmer, D. S.; Leonhardt, U.

    1997-07-01

    Inspired by a recently proposed procedure by Leonhardt and Raymer for wavepacket reconstruction, we calculate the irregular wavefunctions for the bound states of the Coulomb potential. We select the irregular solutions which have the simplest semiclassical limit.

  12. Portable wireless neurofeedback system of EEG alpha rhythm enhances memory.

    Science.gov (United States)

    Wei, Ting-Ying; Chang, Da-Wei; Liu, You-De; Liu, Chen-Wei; Young, Chung-Ping; Liang, Sheng-Fu; Shaw, Fu-Zen

    2017-11-13

    Effect of neurofeedback training (NFT) on enhancement of cognitive function or amelioration of clinical symptoms is inconclusive. The trainability of brain rhythm using a neurofeedback system is uncertainty because various experimental designs are used in previous studies. The current study aimed to develop a portable wireless NFT system for alpha rhythm and to validate effect of the NFT system on memory with a sham-controlled group. The proposed system contained an EEG signal analysis device and a smartphone with wireless Bluetooth low-energy technology. Instantaneous 1-s EEG power and contiguous 5-min EEG power throughout the training were developed as feedback information. The training performance and its progression were kept to boost usability of our device. Participants were blinded and randomly assigned into either the control group receiving random 4-Hz power or Alpha group receiving 8-12-Hz power. Working memory and episodic memory were assessed by the backward digital span task and word-pair task, respectively. The portable neurofeedback system had advantages of a tiny size and long-term recording and demonstrated trainability of alpha rhythm in terms of significant increase of power and duration of 8-12 Hz. Moreover, accuracies of the backward digital span task and word-pair task showed significant enhancement in the Alpha group after training compared to the control group. Our tiny portable device demonstrated success trainability of alpha rhythm and enhanced two kinds of memories. The present study suggest that the portable neurofeedback system provides an alternative intervention for memory enhancement.

  13. Timing of host feeding drives rhythms in parasite replication

    KAUST Repository

    Prior, Kimberley F.

    2018-02-26

    Circadian rhythms enable organisms to synchronise the processes underpinning survival and reproduction to anticipate daily changes in the external environment. Recent work shows that daily (circadian) rhythms also enable parasites to maximise fitness in the context of ecological interactions with their hosts. Because parasite rhythms matter for their fitness, understanding how they are regulated could lead to innovative ways to reduce the severity and spread of diseases. Here, we examine how host circadian rhythms influence rhythms in the asexual replication of malaria parasites. Asexual replication is responsible for the severity of malaria and fuels transmission of the disease, yet, how parasite rhythms are driven remains a mystery. We perturbed feeding rhythms of hosts by 12 hours (i.e. diurnal feeding in nocturnal mice) to desynchronise the host’s peripheral oscillators from the central, light-entrained oscillator in the brain and their rhythmic outputs. We demonstrate that the rhythms of rodent malaria parasites in day-fed hosts become inverted relative to the rhythms of parasites in night-fed hosts. Our results reveal that the host’s peripheral rhythms (associated with the timing of feeding and metabolism), but not rhythms driven by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms. Further investigation reveals that parasite rhythms correlate closely with blood glucose rhythms. In addition, we show that parasite rhythms resynchronise to the altered host feeding rhythms when food availability is shifted, which is not mediated through rhythms in the host immune system. Our observations suggest that parasites actively control their developmental rhythms. Finally, counter to expectation, the severity of disease symptoms expressed by hosts was not affected by desynchronisation of their central and peripheral rhythms. Our study at the intersection of disease ecology and chronobiology opens up a new

  14. Timing of host feeding drives rhythms in parasite replication

    KAUST Repository

    Prior, Kimberley F

    2017-12-07

    Circadian rhythms enable organisms to synchronise the processes underpinning survival and reproduction to anticipate daily changes in the external environment. Recent work shows that daily (circadian) rhythms also enable parasites to maximise fitness in the context of ecological interactions with their hosts. Because parasite rhythms matter for their fitness, understanding how they are regulated could lead to innovative ways to reduce the severity and spread of diseases. Here, we examine how host circadian rhythms influence rhythms in the asexual replication of malaria parasites. Asexual replication is responsible for the severity of malaria and fuels transmission of the disease, yet, how parasite rhythms are driven remains a mystery. We perturbed feeding rhythms of hosts by 12 hours (i.e. diurnal feeding in nocturnal mice) to desynchronise the host\\'s peripheral oscillators from the central, light-entrained oscillator in the brain and their rhythmic outputs. We demonstrate that the rhythms of rodent malaria parasites in day-fed hosts become inverted relative to the rhythms of parasites in night-fed hosts. Our results reveal that the host\\'s peripheral rhythms (associated with the timing of feeding and metabolism), but not rhythms driven by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms. Further investigation reveals that parasite rhythms correlate closely with blood glucose rhythms. In addition, we show that parasite rhythms resynchronise to the altered host feeding rhythms when food availability is shifted, which is not mediated through rhythms in the host immune system. Our observations suggest that parasites actively control their developmental rhythms. Finally, counter to expectation, the severity of disease symptoms expressed by hosts was not affected by desynchronisation of their central and peripheral rhythms. Our study at the intersection of disease ecology and chronobiology opens up a new

  15. On irregularity strength of disjoint union of friendship graphs

    Directory of Open Access Journals (Sweden)

    Ali Ahmad

    2013-11-01

    Full Text Available We investigate the vertex total and edge total modication of the well-known irregularity strength of graphs. We have determined the exact values of the total vertex irregularity strength and the total edge irregularity strength of a disjoint union of friendship graphs.

  16. 16 CFR 501.6 - Cellulose sponges, irregular dimensions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

  17. Dim Light at Night Disrupts Molecular Circadian Rhythms and Affects Metabolism

    Science.gov (United States)

    Fonken, Laura K.; Aubrecht, Taryn G.; Meléndez-Fernández, O. Hecmarie; Weil, Zachary M.; Nelson, Randy J.

    2014-01-01

    With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms which are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electrical lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to nighttime light and investigated changes in the circadian system and body weight. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night attenuate core circadian clock rhythms in the SCN at both the gene and protein level. Moreover, circadian clock rhythms were perturbed in the liver by nighttime light exposure. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide mechanistic evidence for how mild changes in environmental lighting can alter circadian and metabolic function. PMID:23929553

  18. Stochastic models of cellular circadian rhythms in plants help to understand the impact of noise on robustness and clock structure

    Directory of Open Access Journals (Sweden)

    Maria Luisa eGuerriero

    2014-10-01

    Full Text Available Rhythmic behavior is essential for plants; for example, daily (circadian rhythms control photosynthesis and seasonal rhythms regulate their life cycle. The core of the circadian clock is a genetic network that coordinates the expression of specific clock genes in a circadian rhythm reflecting the 24-hour day/night cycle.Circadian clocks exhibit stochastic noise due to the low copy numbers of clock genes and the consequent cell-to-cell variation: this intrinsic noise plays a major role in circadian clocks by inducing more robust oscillatory behavior. Another source of noise is the environment, which causes variation in temperature and light intensity: this extrinsic noise is part of the requirement for the structural complexity of clock networks.Advances in experimental techniques now permit single-cell measurements and the development of single-cell models. Here we present some modeling studies showing the importance of considering both types of noise in understanding how plants adapt to regular and irregular light variations. Stochastic models have proven useful for understanding the effect of regular variations. By contrast, the impact of irregular variations and the interaction of different noise sources are less studied.

  19. Locating irregularly shaped clusters of infection intensity

    DEFF Research Database (Denmark)

    Yiannakoulias, Niko; Wilson, Shona; Kariuki, H. Curtis

    2010-01-01

    of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the "greedy growth scan" is a suitable method for exploratory geographical analysis...... for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis...

  20. Equatorial Ionospheric Irregularities Study from ROCSAT Data

    Science.gov (United States)

    2017-10-20

    UNLIMITED: PB Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Ionospheric irregularity/scintillation occurrences can be caused by external driving ...Academia Sinica, Taipei, Taiwan e-mail: chliu2@gate.sinica.edu.tw phone :886-3-4227151x34757 CoPI: Shin-Yi Su Institution: National Central...University, Chung-Li, Taiwan e-mail: sysu@csrsr.ncu.edu.tw phone :886-3-4227151x57643 CoPI: Lung-Chi Tsai Institution: National Central University, Chung-Li

  1. Artificial periodic irregularities in the auroral ionosphere

    Directory of Open Access Journals (Sweden)

    M. T. Rietveld

    1996-12-01

    Full Text Available Artificial periodic irregularities (API are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the

  2. Mu rhythm desynchronization by tongue thrust observation

    Directory of Open Access Journals (Sweden)

    Kotoe eSakihara

    2015-09-01

    Full Text Available We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD and event-related synchronization (ERS for the mu rhythm (8–13 Hz and beta (13−25 Hz bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance.

  3. Circadian Rhythm Disruption Promotes Lung Tumorigenesis.

    Science.gov (United States)

    Papagiannakopoulos, Thales; Bauer, Matthew R; Davidson, Shawn M; Heimann, Megan; Subbaraj, Lakshmipriya; Bhutkar, Arjun; Bartlebaugh, Jordan; Vander Heiden, Matthew G; Jacks, Tyler

    2016-08-09

    Circadian rhythms are 24-hr oscillations that control a variety of biological processes in living systems, including two hallmarks of cancer, cell division and metabolism. Circadian rhythm disruption by shift work is associated with greater risk for cancer development and poor prognosis, suggesting a putative tumor-suppressive role for circadian rhythm homeostasis. Using a genetically engineered mouse model of lung adenocarcinoma, we have characterized the effects of circadian rhythm disruption on lung tumorigenesis. We demonstrate that both physiologic perturbation (jet lag) and genetic mutation of the central circadian clock components decreased survival and promoted lung tumor growth and progression. The core circadian genes Per2 and Bmal1 were shown to have cell-autonomous tumor-suppressive roles in transformation and lung tumor progression. Loss of the central clock components led to increased c-Myc expression, enhanced proliferation, and metabolic dysregulation. Our findings demonstrate that both systemic and somatic disruption of circadian rhythms contribute to cancer progression. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. [Dynamic Attending Binds Time and Rhythm Perception].

    Science.gov (United States)

    Kuroda, Tsuyoshi; Ono, Fuminori; Kadota, Hiroshi

    2017-11-01

    Relations between time and rhythm perception are discussed in this review of psychophysical research relevant to the multiple-look effect and dynamic-attending theory. Discrimination of two neighboring intervals that are marked by three successive sounds is improved when the presentation of the first (standard, S) interval is repeated before that of the second (comparison, C), as SSSSC. This improvement in sensitivity, called the multiple-look effect, occurs because listeners (1) perceive regular rhythm during the repetition of the standard interval, (2) predict the timing of subsequent sounds, and (3) detect sounds that are deviated from the predicted timing. The dynamic-attending theory attributes such predictions to the entrainment of attentional rhythms. An endogenous attentional rhythm is synchronized with the periodic succession of sounds marking the repeated standard. The standard and the comparison are discriminated on the basis of whether the ending marker of the comparison appears at the peak of the entrained attentional rhythm. This theory is compatible with the findings of recent neurophysiological studies that relate temporal prediction to neural oscillations.

  5. Daily Rhythms in Mobile Telephone Communication.

    Science.gov (United States)

    Aledavood, Talayeh; López, Eduardo; Roberts, Sam G B; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I M; Saramäki, Jari

    2015-01-01

    Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day.

  6. Legal aspects of the EU policy on irregular immigration

    Directory of Open Access Journals (Sweden)

    Voinikov Vadim

    2015-12-01

    Full Text Available This article addresses the issues pertaining to the adoption and development of legislation on irregular migration in the context of uncontrolled growth in the number of immigrants from North Africa and the Middle East to the EU. The article attempts at studying the EU legislation on irregular migration, classifying it, and analysing the prospects of EU migration legislation in the light of an increase in irregular immigration into the EU. The author systematises, classifies the current EU legislation on irregular immigration, and analyses the conditions, in which this legislation was developed. Using the legislation analysis method, the author proposes the following system of EU legislation on irregular immigration: rules preventing assistance to irregular immigration, rules preventing employment of irregular immigrants, rules on the return of irregular migrants and readmission, rules on border control, and rules on collaboration with third countries. The author pays special attention to analysing the current state of irregular immigration to the EU, which was dubbed the ‘greatest migration crisis in Europe’. The conclusion is that the European Union succeeded in the development of pioneering legislation on irregular immigration, which can serve as the basis for reception by other states. However, changes in the political and economic situation in the EU’s southern borderlands made the current legal mechanisms incapable of withstanding new threats. It necessitates a radical reform of the legislation on irregular immigration.

  7. Daily rhythm of cerebral blood flow velocity

    Directory of Open Access Journals (Sweden)

    Spielman Arthur J

    2005-03-01

    Full Text Available Abstract Background CBFV (cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler (TCD ultrasonography. Other variables included core body temperature (CBT, end-tidal carbon dioxide (EtCO2, blood pressure, and heart rate. Salivary dim light melatonin onset (DLMO served as a measure of endogenous circadian phase position. Results A non-linear multiple regression, cosine fit analysis revealed that both the CBT and CBFV rhythm fit a 24 hour rhythm (R2 = 0.62 and R2 = 0.68, respectively. Circadian phase position of CBT occurred at 6:05 am while CBFV occurred at 12:02 pm, revealing a six hour, or 90 degree difference between these two rhythms (t = 4.9, df = 10, p Conclusion In conclusion, time of day variations in CBFV have an approximately 24 hour rhythm under constant conditions, suggesting regulation by a circadian oscillator. The 90 degree-phase angle difference between the CBT and CBFV rhythms may help explain previous findings of lower CBFV values in the morning. The phase difference occurs at a time period during which cognitive performance decrements have been observed and when both cardiovascular and cerebrovascular events occur more frequently. The mechanisms underlying this phase angle difference require further exploration.

  8. Circadian rhythm asynchrony in man during hypokinesis.

    Science.gov (United States)

    Winget, C. M.; Vernikos-Danellis, J.; Cronin, S. E.; Leach, C. S.; Rambaut, P. C.; Mack, P. B.

    1972-01-01

    Posture and exercise were investigated as synchronizers of certain physiologic rhythms in eight healthy male subjects in a defined environment. Four subjects exercised during bed rest. Body temperature (BT), heart rate, plasma thyroid hormone, and plasma steroid data were obtained from the subjects for a 6-day ambulatory equilibration period before bed rest, 56 days of bed rest, and a 10-day recovery period after bed rest. The results indicate that the mechanism regulating the circadian rhythmicity of the cardiovascular system is rigorously controlled and independent of the endocrine system, while the BT rhythm is more closely aligned to the endocrine system.

  9. Circadian Rhythm Sleep-Wake Disorders.

    Science.gov (United States)

    Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C

    2015-12-01

    The circadian system regulates the timing and expression of nearly all biological processes, most notably, the sleep-wake cycle, and disruption of this system can result in adverse effects on both physical and mental health. The circadian rhythm sleep-wake disorders (CRSWDs) consist of 5 disorders that are due primarily to pathology of the circadian clock or to a misalignment of the timing of the endogenous circadian rhythm with the environment. This article outlines the nature of these disorders, the association of many of these disorders with psychiatric illness, and available treatment options. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Circadian rhythm in idiopathic normal pressure hydrocephalus.

    Science.gov (United States)

    Eleftheriou, Andreas; Ulander, Martin; Lundin, Fredrik

    2018-01-01

    The pathogenesis of idiopathic normal pressure hydrocephalus (iNPH) takes place in structures close to the cerebral ventricular system. Suprachiasmatic nucleus (SCN), situated close to the third ventricle, is involved in circadian rhythm. Diurnal disturbances are well-known in demented patients. The cognitive decline in iNPH is potentially reversible after a shunt operation. Diurnal rhythm has never been studied in iNPH. We hypothesize that there is a disturbance of circadian rhythm in iNPH-patients and the aim was to study any changes of the diurnal rhythm (mesor and circadian period) as well as any changes of the diurnal amplitude and acrophase of the activity in iNPH-patients before and after a shunt operation. Twenty consecutive iNPH-patients fulfilling the criteria of the American iNPH-guidelines, 9 males and 11 females, mean age 73 (49-81) years were included. The patients underwent a pre-operative clinical work-up including 10m walk time (w10mt) steps (w10ms), TUG-time (TUGt) and steps (TUGs) and for cognitive function an MMSE score was measured. In order to receive circadian rhythm data actigraphic recordings were performed using the SenseWear 2 (BodyMedia Inc Pittsburgh, PA, USA) actigraph. Cosinor analyses of accelerometry data were performed in "R" using non-linear regression with Levenburg- Marquardt estimation. Pre- and post-operative data regarding mesor, amplitude and circadian period were compared using Wilcoxon-Mann-Whitney test for paired data. Twenty patients were evaluated before and three month post-operatively. Motor function (w10mt, w10ms, TUGt, TUGs) was significantly improved while MMSE was not significantly changed. Actigraphic measurements (mesor, amplitude and circadian period) showed no significant changes after shunt operation. This is the first systematic study of circadian rhythm in iNPH-patients. We found no significant changes in circadian rhythm after shunt surgery. The conceptual idea of diurnal rhythm changes in hydrocephalus is

  11. Circadian rhythm and sleep influences on digestive physiology and disorders

    OpenAIRE

    Vaughn, Bradley; Rotolo,Sean; Roth,Heidi

    2014-01-01

    Bradley V Vaughn, Sean Rotolo, Heidi L Roth Division of Sleep Medicine, Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC, USA Abstract: Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their...

  12. Long wavelength irregularities in the equatorial electrojet

    International Nuclear Information System (INIS)

    Kudeki, E.; Farley, D.T.; Fejer, B.G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach or exceed the ion-acoustic velocity even though the horizontal phase velocity of the wave is considerably smaller. A straightforward extension to the long wavelength regime of the usual linear theory of the electrojet instability explains this and several other observed features of these dominant primary waves

  13. Irregular employment amongst migrants in Spanish cities.

    Science.gov (United States)

    Sole, C; Ribas, N; Bergalli, V; Parella, S

    1998-04-01

    This article presents the irregular employment situation of non-European union immigrants in Spanish cities. Foreign labor is remarkable for its heterogeneity in terms of country of origin, demographic characteristics, and the different ways in which immigrants have entered the job market. Legal immigrants tend to concentrate in five different branches of activity, such as domestic service (mostly women), hotel and restaurant industry, agriculture, building and retail trade. Migrants who work in agriculture suffer the worst labor conditions than all other migrants. However, all migrants experience difficulty in obtaining residency and labor permits. Four integration strategies among Moroccan immigrants in Catalonia are discussed and can be viewed as support networks of the immigrants.

  14. Monkey Lipsmacking Develops Like the Human Speech Rhythm

    Science.gov (United States)

    Morrill, Ryan J.; Paukner, Annika; Ferrari, Pier F.; Ghazanfar, Asif A.

    2012-01-01

    Across all languages studied to date, audiovisual speech exhibits a consistent rhythmic structure. This rhythm is critical to speech perception. Some have suggested that the speech rhythm evolved "de novo" in humans. An alternative account--the one we explored here--is that the rhythm of speech evolved through the modification of rhythmic facial…

  15. EFFECTS OF CIRCADIAN RHYTHM ON BALANCE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Karagul Osman

    2017-09-01

    Full Text Available Introduction. The aim of the study was to examine the effect of circadian rhythm on dynamic balance performance and to determine the role of physical activity level, body temperature, chronotype, and gender in this possible effect. Material and

  16. Working night shifts affects surgeons' biological rhythm

    DEFF Research Database (Denmark)

    Amirian, Ilda; Andersen, Lærke T; Rosenberg, Jacob

    2015-01-01

    BACKGROUND: Chronic sleep deprivation combined with work during the night is known to affect performance and compromise residents' own safety. The aim of this study was to examine markers of circadian rhythm and the sleep-wake cycle in surgeons working night shifts. METHODS: Surgeons were monitor...

  17. Egg-laying rhythm in Drosophila melanogaster

    Indian Academy of Sciences (India)

    2008-12-31

    Dec 31, 2008 ... production of oocytes to egg-laying on selected sites (Alle- mand 1976b; Yang et al. .... (vii) Is the egg-laying rhythm regulated by hormones? .... were shown to be induced by factors synthesized in the re- productive tract of the ...

  18. Irregular activity arises as a natural consequence of synaptic inhibition

    International Nuclear Information System (INIS)

    Terman, D.; Rubin, J. E.; Diekman, C. O.

    2013-01-01

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects

  19. Irregular activity arises as a natural consequence of synaptic inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Terman, D., E-mail: terman@math.ohio-state.edu [Department of Mathematics, The Ohio State University, Columbus, Ohio 43210 (United States); Rubin, J. E., E-mail: jonrubin@pitt.edu [Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Diekman, C. O., E-mail: diekman@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

    2013-12-15

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

  20. Airway surface irregularities promote particle diffusion in the human lung

    International Nuclear Information System (INIS)

    Martonen, T.; North Carolina Univ., Chapel Hill, NC; Zhang, Z.; Yang, Y.; Bottei, G.

    1995-01-01

    Current NCRP and ICRP particle deposition models employed in risk assessment analyses treat the airways of the human lung as smooth-walled tubes. However, the upper airways of the tracheobronchial (TB) tree are line with cartilaginous rings. Recent supercomputer simulations of in vivo conditions (cited herein), where cartilaginous ring morphologies were based upon fibre-optic bronchoscope examinations, have clearly demonstrated their profound effects upon fluid dynamics. A physiologically based analytical model of fluid dynamics is presented, focusing upon applications to particle diffusion within the TB tree. The new model is the first to describe particle motion while simultaneously simulating effects of wall irregularities, entrance conditions and tube curvatures. This study may explain the enhanced deposition by particle diffusion detected in replica case experiments and have salient implications for the clinically observed preferential distributions of bronchogenic carcinomas associated with inhaled radionuclides. (author)

  1. Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

    NARCIS (Netherlands)

    Janic, M.

    2009-01-01

    This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

  2. Decomposing Oriented Graphs into Six Locally Irregular Oriented Graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien; Renault, Gabriel

    2016-01-01

    An undirected graph G is locally irregular if every two of its adjacent vertices have distinct degrees. We say that G is decomposable into k locally irregular graphs if there exists a partition E1∪E2∪⋯∪Ek of the edge set E(G) such that each Ei induces a locally irregular graph. It was recently co...

  3. RNAi of the circadian clock gene period disrupts the circadian rhythm but not the circatidal rhythm in the mangrove cricket

    OpenAIRE

    Takekata, Hiroki; Matsuura, Yu; Goto, Shin G.; Satoh, Aya; Numata, Hideharu

    2012-01-01

    The clock mechanism for circatidal rhythm has long been controversial, and its molecular basis is completely unknown. The mangrove cricket, Apteronemobius asahinai, shows two rhythms simultaneously in its locomotor activity: a circatidal rhythm producing active and inactive phases as well as a circadian rhythm modifying the activity intensity of circatidal active phases. The role of the clock gene period (per), one of the key components of the circadian clock in insects, was investigated in t...

  4. Working irregular shift patterns is associated with functional constipation among healthy trainee nurses

    Directory of Open Access Journals (Sweden)

    Ali Ebrahim

    2017-11-01

    Full Text Available The circadian system has a role in regulating gastrointestinal physiology. Perturbation of this system is associated with gastrointestinal tract dysfunction. Shiftwork and poor sleep quality are associated with functional gastrointestinal disorders among many professional groups. This study compared bowel habits between trainee nurses with regular and irregular patterns of shiftwork. Male and female nursing students, enrolled on the first year (regular shifts; n=49 and the fourth year (irregular shifts, n=48 of a nursing degree course were surveyed. Questionnaires were used to assess functional diarrhea and constipation over a three month period. The prevalence of functional constipation among regular shift workers was lower than that found among irregular shift workers; 31.3% and 61.2%, respectively. There was no difference between the two groups in relation to the prevalence of diarrhea. This suggests an association between shiftwork and functional constipation, but not with functional diarrhea.

  5. Biologic rhythms derived from Siberian mammoths' hairs.

    Directory of Open Access Journals (Sweden)

    Mike Spilde

    Full Text Available Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was ∼31 cms/year and ∼16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios, which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

  6. Characteristics of ionospheric irregularities causing scintillations at VHF/UHF

    International Nuclear Information System (INIS)

    Vats, H.O.; Deshpande, M.R.; Rastogi, R.G.

    1978-01-01

    Some properties of ionization irregularities using amplitude scintillation records of radio beacons from ATS-6 (phase II) at Ootacamund, India have been investigated. For the estimation of scale-size and strength of the irregularities a simple diffraction model has been used which explains only weak and moderate equatorial scintillation observations. It was found that the scale sizes of day time E-region irregularities are smaller than those in the F-region during night time in addition, irregularities are generated initially at large scale sizes which later break up into smaller scale sizes

  7. Adolescents at clinical-high risk for psychosis: Circadian rhythm disturbances predict worsened prognosis at 1-year follow-up.

    Science.gov (United States)

    Lunsford-Avery, Jessica R; Gonçalves, Bruno da Silva Brandão; Brietzke, Elisa; Bressan, Rodrigo A; Gadelha, Ary; Auerbach, Randy P; Mittal, Vijay A

    2017-11-01

    Individuals with psychotic disorders experience disruptions to both the sleep and circadian components of the sleep/wake cycle. Recent evidence has supported a role of sleep disturbances in emerging psychosis. However, less is known about how circadian rhythm disruptions may relate to psychosis symptoms and prognosis for adolescents with clinical high-risk (CHR) syndromes. The present study examines circadian rest/activity rhythms in CHR and healthy control (HC) youth to clarify the relationships among circadian rhythm disturbance, psychosis symptoms, psychosocial functioning, and the longitudinal course of illness. Thirty-four CHR and 32 HC participants were administered a baseline evaluation, which included clinical interviews, 5days of actigraphy, and a sleep/activity diary. CHR (n=29) participants were re-administered clinical interviews at a 1-year follow-up assessment. Relative to HC, CHR youth exhibited more fragmented circadian rhythms and later onset of nocturnal rest. Circadian disturbances (fragmented rhythms, low daily activity) were associated with increased psychotic symptom severity among CHR participants at baseline. Circadian disruptions (lower daily activity, rhythms that were more fragmented and/or desynchronized with the light/dark cycle) also predicted severity of psychosis symptoms and psychosocial impairment at 1-year follow-up among CHR youth. Circadian rhythm disturbances may represent a potential vulnerability marker for emergence of psychosis, and thus, rest/activity rhythm stabilization has promise to inform early-identification and prevention/intervention strategies for CHR youth. Future studies with longer study designs are necessary to further examine circadian rhythms in the prodromal period and rates of conversion to psychosis among CHR teens. Copyright © 2017. Published by Elsevier B.V.

  8. Advances in electron dosimetry of irregular fields; Avances en dosimetria de electrones de campos irregulares

    Energy Technology Data Exchange (ETDEWEB)

    Mendez V, J. [Departamento de Radioterapia, Instituto de Enfermedades Neoplasicas, Avenida Angamos Este 2520, Lima 34 (Peru)

    1998-12-31

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm{sup 2} with percentile error less than 1 % . (Author)

  9. Therapeutic strategies for circadian rhythm and sleep disturbances in Huntington disease.

    Science.gov (United States)

    van Wamelen, Daniel J; Roos, Raymund Ac; Aziz, Nasir A

    2015-12-01

    Aside from the well-known motor, cognitive and psychiatric signs and symptoms, Huntington disease (HD) is also frequently complicated by circadian rhythm and sleep disturbances. Despite the observation that these disturbances often precede motor onset and have a high prevalence, no studies are available in HD patients which assess potential treatments. In this review, we will briefly outline the nature of circadian rhythm and sleep disturbances in HD and subsequently focus on potential treatments based on findings in other neurodegenerative diseases with similarities to HD, such as Parkinson and Alzheimer disease. The most promising treatment options to date for circadian rhythm and sleep disruption in HD include melatonin (agonists) and bright light therapy, although further corroboration in clinical trials is warranted.

  10. Compensation for unfavorable characteristics of irregular individual shift rotas.

    Science.gov (United States)

    Knauth, Peter; Jung, Detlev; Bopp, Winfried; Gauderer, Patric C; Gissel, Andreas

    2006-01-01

    Some employees of TV companies, such as those who produce remote TV programs, have to cope with very irregular rotas and many short-term schedule deviations. Many of these employees complain about the negative effects of such on their wellbeing and private life. Therefore, a working group of employers, council representatives, and researchers developed a so-called bonus system. Based on the criteria of the BESIAK system, the following list of criteria for the ergonomic assessment of irregular shift systems was developed: proportion of night hours worked between 22 : 00 and 01 : 00 h and between 06 : 00 and 07 : 00 h, proportion of night hours worked between 01 : 00 and 06 : 00 h, number of successive night shifts, number of successive working days, number of shifts longer than 9 h, proportion of phase advances, off hours on weekends, work hours between 17 : 00 and 23 : 00 h from Monday to Friday, number of working days with leisure time at remote places, and sudden deviations from the planned shift rota. Each individual rota was evaluated in retrospect. If pre-defined thresholds of criteria were surpassed, bonus points were added to the worker's account. In general, more bonus points add up to more free time. Only in particular cases was monetary compensation possible for some criteria. The bonus point system, which was implemented in the year 2002 for about 850 employees of the TV company, has the advantages of more transparency concerning the unfavorable characteristics of working-time arrangements, incentive for superiors to design "good" rosters that avoid the bonus point thresholds (to reduce costs), positive short-term effects on the employee social life, and expected positive long-term effects on the employee health. In general, the most promising approach to cope with the problems of shift workers in irregular and flexible shift systems seems to be to increase their influence on the arrangement of working times. If this is not possible, bonus point systems

  11. [Interpersonal and social rhythm therapy (IPSRT)].

    Science.gov (United States)

    Bottai, T; Biloa-Tang, M; Christophe, S; Dupuy, C; Jacquesy, L; Kochman, F; Meynard, J-A; Papeta, D; Rahioui, H; Adida, M; Fakra, E; Kaladjian, A; Pringuey, D; Azorin, J-M

    2010-12-01

    Bipolar disorder is common, recurrent, often severe and debiliting disorder. All types of bipolar disorder have a common determinant: depressive episode. It is justify to propose a psychotherapy which shown efficacy in depression. Howewer, perturbations in circadian rhythms have been implicated in the genesis of each episode of the illness. Biological circadian dysregulation can be encouraged by alteration of time-givers (Zeitgebers) or occurrence of time-disturbers (Zeitstörers). Addition of social rhythm therapy to interpersonal psychotherapy leads to create a new psychotherapy adaptated to bipolar disorders: InterPersonal and Social Rhythm Therapy (IPSRT). IPSRT, in combinaison with medication, has demonstrated efficacy as a treatment for bipolar disorders. IPSRT combines psychoeducation, behavioral strategy to regularize daily routines and interpersonal psychotherapy which help patients cope better with the multiple psychosocial and relationship problems associated with this chronic disorder. The main issues of this psychotherapy are: to take the history of the patient's illness and review of medication, to help patient for "grief for the lost healthy self" translated in the french version in "acceptance of a long-term medical condition", to give the sick role, to examinate the current relationships and changes proximal to the emergence of mood symptoms in the four problem areas (unresolved grief, interpersonal disputes, role transitions, role déficits), to examinate and increase daily routines and social rhythms. French version of IPSRT called TIPARS (with few differences), a time-limited psychotherapy, in 24 sessions during approximatively 6 months, is conducted in three phases. In the initial phase, the therapist takes a thorough history of previous episodes and their interpersonal context and a review of previous medication, provides psychoeducation, evaluates social rhythms, introduces the Social Rhythm Metric, identifies the patient's main interpersonal

  12. Irregular radiation response of a chondrosarcoma

    International Nuclear Information System (INIS)

    Marsden, J.J.; Kember, N.F.; Shaw, J.E.H.

    1980-01-01

    The DC II mouse chondrosarcoma was shown to be a potentially valuable radiobiological tumour system since it recovered from radiation injury by regrowth from clones that could be counted in histological sections. Unfortunately, the normal growth of this tumour following s.c. implantation in the thigh was irregular both in the time before growth became evident and in the rate of growth. The response to radiation was also unreliable since tumours irradiated with the same dose (e.g. 30 Gy) showed a range of responses from shrinkage to no detectable change in growth rate. The delay in normal growth can be attributed largely to delays in vascularization while changes in growth rate may be explained by differences in tumour architecture. Radiation response may depend on variations in hypoxic fraction and in relative cellularity. Tumours having the same external dimensions may differ by a factor of 80 in the numbers of tumour cells they contain. This chondrosarcoma may prove a closer model to some human tumours than many transplantable tumours that display regular growth patterns. (author)

  13. Evaporation From Soil Containers With Irregular Shapes

    Science.gov (United States)

    Assouline, Shmuel; Narkis, Kfir

    2017-11-01

    Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

  14. Design strategies for irregularly adapting parallel applications

    International Nuclear Information System (INIS)

    Oliker, Leonid; Biswas, Rupak; Shan, Hongzhang; Sing, Jaswinder Pal

    2000-01-01

    Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance of dynamically adapting computations. In this work, we examine two major classes of adaptive applications, under five competing programming methodologies and four leading parallel architectures. Results indicate that it is possible to achieve message-passing performance using shared-memory programming techniques by carefully following the same high level strategies. Adaptive applications have computational work loads and communication patterns which change unpredictably at runtime, requiring dynamic load balancing to achieve scalable performance on parallel machines. Efficient parallel implementations of such adaptive applications are therefore a challenging task. This work examines the implementation of two typical adaptive applications, Dynamic Remeshing and N-Body, across various programming paradigms and architectural platforms. We compare several critical factors of the parallel code development, including performance, programmability, scalability, algorithmic development, and portability

  15. Multiresolution Analysis Adapted to Irregularly Spaced Data

    Directory of Open Access Journals (Sweden)

    Anissa Mokraoui

    2009-01-01

    Full Text Available This paper investigates the mathematical background of multiresolution analysis in the specific context where the signal is represented by irregularly sampled data at known locations. The study is related to the construction of nested piecewise polynomial multiresolution spaces represented by their corresponding orthonormal bases. Using simple spline basis orthonormalization procedures involves the construction of a large family of orthonormal spline scaling bases defined on consecutive bounded intervals. However, if no more additional conditions than those coming from multiresolution are imposed on each bounded interval, the orthonormal basis is represented by a set of discontinuous scaling functions. The spline wavelet basis also has the same problem. Moreover, the dimension of the corresponding wavelet basis increases with the spline degree. An appropriate orthonormalization procedure of the basic spline space basis, whatever the degree of the spline, allows us to (i provide continuous scaling and wavelet functions, (ii reduce the number of wavelets to only one, and (iii reduce the complexity of the filter bank. Examples of the multiresolution implementations illustrate that the main important features of the traditional multiresolution are also satisfied.

  16. Resolution optimization with irregularly sampled Fourier data

    International Nuclear Information System (INIS)

    Ferrara, Matthew; Parker, Jason T; Cheney, Margaret

    2013-01-01

    Image acquisition systems such as synthetic aperture radar (SAR) and magnetic resonance imaging often measure irregularly spaced Fourier samples of the desired image. In this paper we show the relationship between sample locations, their associated backprojection weights, and image resolution as characterized by the resulting point spread function (PSF). Two new methods for computing data weights, based on different optimization criteria, are proposed. The first method, which solves a maximal-eigenvector problem, optimizes a PSF-derived resolution metric which is shown to be equivalent to the volume of the Cramer–Rao (positional) error ellipsoid in the uniform-weight case. The second approach utilizes as its performance metric the Frobenius error between the PSF operator and the ideal delta function, and is an extension of a previously reported algorithm. Our proposed extension appropriately regularizes the weight estimates in the presence of noisy data and eliminates the superfluous issue of image discretization in the choice of data weights. The Frobenius-error approach results in a Tikhonov-regularized inverse problem whose Tikhonov weights are dependent on the locations of the Fourier data as well as the noise variance. The two new methods are compared against several state-of-the-art weighting strategies for synthetic multistatic point-scatterer data, as well as an ‘interrupted SAR’ dataset representative of in-band interference commonly encountered in very high frequency radar applications. (paper)

  17. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  18. 14 CFR 135.65 - Reporting mechanical irregularities.

    Science.gov (United States)

    2010-01-01

    ... irregularities and their correction. (b) The pilot in command shall enter or have entered in the aircraft maintenance log each mechanical irregularity that comes to the pilot's attention during flight time. Before each flight, the pilot in command shall, if the pilot does not already know, determine the status of...

  19. Uniform irradiation of irregularly shaped cavities for photodynamic therapy

    NARCIS (Netherlands)

    Rem, A. I.; van Gemert, M. J.; van der Meulen, F. W.; Gijsbers, G. H.; Beek, J. F.

    1997-01-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a

  20. Software support for irregular and loosely synchronous problems

    Science.gov (United States)

    Choudhary, A.; Fox, G.; Hiranandani, S.; Kennedy, K.; Koelbel, C.; Ranka, S.; Saltz, J.

    1992-01-01

    A large class of scientific and engineering applications may be classified as irregular and loosely synchronous from the perspective of parallel processing. We present a partial classification of such problems. This classification has motivated us to enhance FORTRAN D to provide language support for irregular, loosely synchronous problems. We present techniques for parallelization of such problems in the context of FORTRAN D.

  1. Regularisation of irregular verbs in child English second language ...

    African Journals Online (AJOL)

    Data was collected from the language of English medium preschool children. The study concludes that when the Blocking Principle interferes, children resort to a novel interlanguage rule that regularises irregular verbs. This interlanguage rule applies in a similar way to all irregular verbs, thus children produce utterances ...

  2. The majority of irregular menstrual cycles in adolescence are ovulatory: results of a prospective study.

    Science.gov (United States)

    Peña, Alexia S; Doherty, Dorota A; Atkinson, Helen C; Hickey, Martha; Norman, Robert J; Hart, Roger

    2018-03-01

    While ovulation is most likely to occur in adolescent girls with regular menstrual cycles, there are limited data on the incidence of ovulation in girls with irregular menstrual cycles in early postmenarcheal years. The aim of the study was to evaluate the presence of ovulation in healthy postmenarcheal girls with irregular menstrual cycles. Prospective cohort study over 12 weeks including 40 healthy postmenarcheal girls recruited from the population-based cohort of adolescents from Western Australian Pregnancy Cohort (Raine) Study with irregular menstrual cycles defined by either menstrual cycles 35 days in duration or cycle length that varied from month to month by >4 days according to menstrual diaries. Ovulation defined by urinary pregnanediol-3α-glucuronide/creatinine measurements higher than three times above minimum value obtained from 12 samples (1 per week). Forty girls (37 Caucasians) with irregular menstrual cycles aged 15.1 (median (IQR) 14.9-15.4) years who were 2.3 (1.9-3.3) years postmenarche were assessed. Urinary pregnanediol-3α-glucuronide/creatinine values identified that 33 girls (82.5%) ovulated during the 3 months of observation and 7 girls had anovulatory cycles. Menstrual diaries collected for a median (IQR) of 159 (137.5-188.2) days showed median minimal and maximum menstrual cycle duration of 24 (11.5-29) and 38.5 (35-48) days, respectively. A large proportion of healthy adolescent girls with irregular menstrual cycles are still ovulating despite irregular and infrequent menses. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  3. Effects of N-acetylcysteine and imipramine in a model of acute rhythm disruption in BALB/c mice.

    Science.gov (United States)

    Pilz, Luísa K; Trojan, Yasmine; Quiles, Caroline L; Benvenutti, Radharani; Melo, Gabriela; Levandovski, Rosa; Hidalgo, Maria Paz L; Elisabetsky, Elaine

    2015-03-01

    Circadian rhythm disturbances are among the risk factors for depression, but specific animal models are lacking. This study aimed to characterize the effects of acute rhythm disruption in mice and investigate the effects of imipramine and N-acetylcysteine (NAC) on rhythm disruption-induced changes. Mice were exposed to 12:12-hour followed by 10:10-hour light:dark cycles (LD); under the latter, mice were treated with saline, imipramine or NAC. Rhythms of rest/activity and temperature were assessed with actigraphs and iButtons, respectively. Hole-board and social preference tests were performed at the beginning of the experiment and again at the 8th 10:10 LD, when plasma corticosterone and IL-6 levels were also assessed. Actograms showed that the 10:10 LD schedule prevents the entrainment of temperature and activity rhythms for at least 13 cycles. Subsequent light regimen change activity and temperature amplitudes showed similar patterns of decline followed by recovery attempts. During the 10:10 LD schedule, activity and temperature amplitudes were significantly decreased (paired t test), an effect exacerbated by imipramine (ANOVA/SNK). The 10:10 LD schedule increased anxiety (paired t test), an effect prevented by NAC (30 mg/kg). This study identified mild but significant behavioral changes at specific time points after light regimen change. We suggest that if repeated overtime, these subtle changes may contribute to lasting behavioral disturbancess relevant to anxiety and mood disorders. Data suggest that imipramine may contribute to sustained rhythm disturbances, while NAC appears to prevent rhythm disruption-induced anxiety. Associations between sleep/circadian disturbances and the recurrence of depressive episodes underscore the relevance of potential drug-induced maintenance of disturbed rhythms.

  4. Sleep, circadian rhythms, and athletic performance.

    Science.gov (United States)

    Thun, Eirunn; Bjorvatn, Bjørn; Flo, Elisabeth; Harris, Anette; Pallesen, Ståle

    2015-10-01

    Sleep deprivation and time of day are both known to influence performance. A growing body of research has focused on how sleep and circadian rhythms impact athletic performance. This review provides a systematic overview of this research. We searched three different databases for articles on these issues and inspected relevant reference lists. In all, 113 articles met our inclusion criteria. The most robust result is that athletic performance seems to be best in the evening around the time when the core body temperature typically is at its peak. Sleep deprivation was negatively associated with performance whereas sleep extension seems to improve performance. The effects of desynchronization of circadian rhythms depend on the local time at which performance occurs. The review includes a discussion of differences regarding types of skills involved as well as methodological issues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Regulation of reproduction by the circadian rhythms.

    Science.gov (United States)

    Zhang, Wen-Xiang; Chen, Si-Yu; Liu, Chang

    2016-12-25

    Mammals synchronize their circadian activity primarily to the cycles of light and darkness in the environment. Circadian rhythm is controlled by the central clock in the hypothalamic suprachiasmatic nucleus (SCN) and the peripheral clocks in various tissues. More importantly, the central clock can integrate photic/nonphotic signals to generate rhythmic outputs, and then drive the slave oscillators in peripheral tissues through neuroendocrine and behavioral signals. Human reproductive activities, as some other physiological functions, are controlled by the biological clocks. Accumulating lines of epidemiological and genetic evidence indicate that disruption of circadian clock can be directly involved in multiple pathological processes, including infertility. In this review, we mainly discuss the presence of a circadian clock in reproductive tissues and its roles in follicles development, ovulation, spermatogenesis, fertilization and embryo implantation, etc. As the increased shift work and assisted reproductive technologies possibly disrupt circadian rhythmicity to impact reproduction, the importance of circadian rhythms should be highlighted in the regulation of reproductive process.

  6. Circadian rhythms and obesity in mammals.

    Science.gov (United States)

    Froy, Oren

    2012-01-01

    Obesity has become a serious public health problem and a major risk factor for the development of illnesses, such as insulin resistance and hypertension. Attempts to understand the causes of obesity and develop new therapeutic strategies have mostly focused on caloric intake and energy expenditure. Recent studies have shown that the circadian clock controls energy homeostasis by regulating the circadian expression and/or activity of enzymes, hormones, and transport systems involved in metabolism. Moreover, disruption of circadian rhythms leads to obesity and metabolic disorders. Therefore, it is plausible that resetting of the circadian clock can be used as a new approach to attenuate obesity. Feeding regimens, such as restricted feeding (RF), calorie restriction (CR), and intermittent fasting (IF), provide a time cue and reset the circadian clock and lead to better health. In contrast, high-fat (HF) diet leads to disrupted circadian expression of metabolic factors and obesity. This paper focuses on circadian rhythms and their link to obesity.

  7. Irregular conformal block, spectral curve and flow equations

    International Nuclear Information System (INIS)

    Choi, Sang Kwan; Rim, Chaiho; Zhang, Hong

    2016-01-01

    Irregular conformal block is motivated by the Argyres-Douglas type of N=2 super conformal gauge theory. We investigate the classical/NS limit of irregular conformal block using the spectral curve on a Riemann surface with irregular punctures, which is equivalent to the loop equation of irregular matrix model. The spectral curve is reduced to the second order (Virasoro symmetry, SU(2) for the gauge theory) and third order (W_3 symmetry, SU(3)) differential equations of a polynomial with finite degree. The conformal and W symmetry generate the flow equations in the spectral curve and determine the irregular conformal block, hence the partition function of the Argyres-Douglas theory ala AGT conjecture.

  8. Rhythm perception and production predict reading abilities in developmental dyslexia

    Directory of Open Access Journals (Sweden)

    Elena eFlaugnacco

    2014-06-01

    Full Text Available Rhythm organizes events in time and plays a major role in music, but also in the phonology and prosody of a language. Interestingly, children with developmental dyslexia - a learning disability that affects reading acquisition despite normal intelligence and adequate education - have a poor rhythmic perception. It has been suggested that an accurate perception of rhythmical/metrical structure, that requires accurate perception of rise time, may be critical for phonological development and subsequent literacy. This hypothesis is mostly based on results showing a high degree of correlation between phonological awareness and metrical skills, using a very specific metrical task. We present new findings from the analysis of a sample of 48 children with a diagnosis of dyslexia, without comorbidities. These children were assessed with neuropsychological tests, as well as specifically-devised psychoacoustic and musical tasks mostly testing temporal abilities. Associations were tested by multivariate analyses including data mining strategies, correlations and most importantly logistic regressions to understand to what extent the different auditory and musical skills can be a robust predictor of reading and phonological skills. Results show a strong link between several temporal skills and phonological and reading abilities. These findings are discussed in the framework of the neuroscience literature comparing music and language processing, with a particular interest in the links between rhythm processing in music and language.

  9. Circadian rhythms of women with fibromyalgia

    Science.gov (United States)

    Klerman, E. B.; Goldenberg, D. L.; Brown, E. N.; Maliszewski, A. M.; Adler, G. K.

    2001-01-01

    Fibromyalgia syndrome is a chronic and debilitating disorder characterized by widespread nonarticular musculoskeletal pain whose etiology is unknown. Many of the symptoms of this syndrome, including difficulty sleeping, fatigue, malaise, myalgias, gastrointestinal complaints, and decreased cognitive function, are similar to those observed in individuals whose circadian pacemaker is abnormally aligned with their sleep-wake schedule or with local environmental time. Abnormalities in melatonin and cortisol, two hormones whose secretion is strongly influenced by the circadian pacemaker, have been reported in women with fibromyalgia. We studied the circadian rhythms of 10 women with fibromyalgia and 12 control healthy women. The protocol controlled factors known to affect markers of the circadian system, including light levels, posture, sleep-wake state, meals, and activity. The timing of the events in the protocol were calculated relative to the habitual sleep-wake schedule of each individual subject. Under these conditions, we found no significant difference between the women with fibromyalgia and control women in the circadian amplitude or phase of rhythms of melatonin, cortisol, and core body temperature. The average circadian phases expressed in hours posthabitual bedtime for women with and without fibromyalgia were 3:43 +/- 0:19 and 3:46 +/- 0:13, respectively, for melatonin; 10:13 +/- 0:23 and 10:32 +/- 0:20, respectively for cortisol; and 5:19 +/- 0:19 and 4:57 +/- 0:33, respectively, for core body temperature phases. Both groups of women had similar circadian rhythms in self-reported alertness. Although pain and stiffness were significantly increased in women with fibromyalgia compared with healthy women, there were no circadian rhythms in either parameter. We suggest that abnormalities in circadian rhythmicity are not a primary cause of fibromyalgia or its symptoms.

  10. Star Formation Histories of Dwarf Irregular Galaxies

    Science.gov (United States)

    Skillman, Evan

    1995-07-01

    We propose to obtain deep WFPC2 `BVI' color-magnitude diagrams {CMDs} for the dwarf irregular {dI} Local Group galaxies GR 8, Leo A, Pegasus, and Sextans A. In addition to resolved stars, we will use star clusters, and especially any globulars, to probe the history of intense star formation. These data will allow us to map the Pop I and Pop II stellar components, and thereby construct the first detailed star formation histories for non-interacting dI galaxies. Our results will bear on a variety of astrophysical problems, including the evolution of small galaxies, distances in the Local Group, age-metallicity distributions in small galaxies, ages of dIs, and the physics of star formation. The four target galaxies are typical dI systems in terms of luminosity, gas content, and H II region abundance, and represent a range in current star forming activity. They are sufficiently near to allow us to reach to stars at M_V = 0, have 0.1 of the luminosity of the SMC and 0.25 of its oxygen abundance. Unlike the SMC, these dIs are not near giant galaxies. This project will allow the extension of our knowledge of stellar populations in star forming galaxies from the spirals in the Local Group down to its smallest members. We plan to take maximum advantage of the unique data which this project will provide. Our investigator team brings extensive and varied experience in studies of dwarf galaxies, stellar populations, imaging photometry, and stellar evolution to this project.

  11. Development of the cortisol circadian rhythm in the light of stress early in life.

    Science.gov (United States)

    Simons, Sterre S H; Beijers, Roseriet; Cillessen, Antonius H N; de Weerth, Carolina

    2015-12-01

    The secretion of the stress hormone cortisol follows a diurnal circadian rhythm. There are indications that this rhythm is affected by stress early in life. This paper addresses the development of the cortisol circadian rhythm between 1 and 6 years of age, and the role of maternal stress and anxiety early in the child's life on this (developing) rhythm. Participants were 193 healthy mother-child dyads from a community sample. Self-reported maternal stress and anxiety and physiological stress (saliva cortisol), were assessed prenatally (gestational week 37). Postnatally, self-reported maternal stress and anxiety were measured at 3, 6, 12, 30, and 72 months. Saliva cortisol samples from the children were collected on two days (four times each day) at 12, 30, and 72 months of age. The total amount of cortisol during the day and the cortisol decline over the day were determined to indicate children's cortisol circadian rhythm. Multilevel analyses showed that the total amount of cortisol decreased between 1 and 6 years. Furthermore, more maternal pregnancy-specific stress was related to higher total amounts of cortisol in the child. Higher levels of early postnatal maternal anxiety were associated with flatter cortisol declines in children. Higher levels of early postnatal maternal daily hassles were associated with steeper child cortisol declines over the day. These results indicated developmental change in children's cortisol secretion from 1 to 6 years and associations between maternal stress and anxiety early in children's lives and children's cortisol circadian rhythm in early childhood. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Basic Principles of Interpersonal Social Rhythm Therapy in Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Gokben Hizli Sayar

    2014-08-01

    Full Text Available Interpersonal Social Rhythm Therapy is a psychotherapy modality that helps the patient recognize the relationship between disruptions in social rhythms and the onset of previous episodes of psychiatric disorders. It uses psychoeducation and behavioral techniques to maintain social rhythm and sleep/wake regularity. It is closely related to and ldquo;social zeitgeber theory and rdquo; that emphasizes the importance that social rhythm regularity may play in synchronization of circadian rhythms in individuals with or at risk for bipolar spectrum disorders. Interpersonal and social rhythm therapy have been shown to stabilize social rhythms and enhance course and outcome in bipolar disorder. This review focuses on the theoretical principles and the basic steps of interpersonal and social rhythm therapy as a psychotherapy approach in bipolar disorder. PubMed, Scopus, Google Scholar databases were searched without temporal restriction. Search terms included interpersonal social rhythm therapy, bipolar, mood disorders. Abstracts were reviewed for relevance, and randomized controlled trials of interpersonal and social rhythm therapy in bipolar disorder selected. These researches also summarized on the final part of this review. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 438-446

  13. The relationship between reproduction of the jump’s rhythm and technical score of their execution by gymnasts at the stage of initial training

    Directory of Open Access Journals (Sweden)

    Oksana Zaplatynska

    2016-06-01

    Full Text Available Purpose: to determine the interconnection between quality of performance of the jumps and reproduction of the rhythm of jumps by gymnasts at the stage of initial training. Material & Methods: to determine the relationship between reproduction of rhythm and evaluation by the quality of technique of the jumps we used expert assessment, check the accuracy of the reproduction of rhythm with the help of computer program "rhythmic", methods of mathematical statistics. Results: the study found the correlation between reproduction of rhythm and summing-up of quality the technique of jumps by the gymnasts at the stage of initial training. Conclusions: the ability to reproduce a predetermined rhythm influences the level of technical readiness of gymnasts at the stage of initial training.

  14. Biologic Rhythms Derived from Siberian Mammoths Hairs

    Energy Technology Data Exchange (ETDEWEB)

    M Spilde; A Lanzirotti; C Qualls; G Phillips; A Ali; L Agenbroad; O Appenzeller

    2011-12-31

    Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was {approx}31 cms/year and {approx}16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios), which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

  15. Circadian Rhythm and Sleep During Prolonged Antarctic Residence at Chinese Zhongshan Station.

    Science.gov (United States)

    Chen, Nan; Wu, Quan; Xiong, Yanlei; Chen, Guang; Song, Dandan; Xu, Chengli

    2016-12-01

    Residence at Zhongshan Station (69°22'24″S, 76°22'40″E) for over 1 year exposes winter-over members to marked changes of light-dark cycle, ranging from the constant daylight of polar days to the constant darkness of polar nights, in addition to geographic and social isolation. This extreme photoperiodic environment may increase the risk of sleep disturbances and circadian desynchrony. The aim of this study was to investigate the circadian rhythm and sleep phase of Chinese winter-over expeditioners at Zhongshan Station. This study was conducted on 17 healthy male participants before departure from Shanghai and during residence at Zhongshan Station for 1 year (before winter, mid-winter, and end of winter). Sequential urine samples over 48 hours were obtained, 6-sulphatoxymelatonin in urine was assessed, and the circadian rhythm was analyzed by a cosine curve-fitting method. Participants' sleep parameters were obtained from wrist actigraphy and sleep logs. Morningness-Eveningness Questionnaire and Seasonal Pattern Assessment Questionnaire were completed. The acrophase of 6-sulphatoxymelatonin rhythm, sleep onset, sleep offset, and mid-sleep time were delayed significantly (P circadian rhythm and sleep phase, later chronotype, and incidence of subsyndromal seasonal affective disorder. An appropriate combination of artificial bright light during dark winter months and a strict social schedule are recommended in a winter-over station in Antarctica. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  16. The normal squamocolumnar junction is circumferentially even and minimal irregularities are manifestations of gastroesophageal acid reflux.

    Science.gov (United States)

    Guerrero Garcia Hall, Mats; Wenner, Jörgen; Öberg, Stefan

    2017-03-01

    The macroscopic appearance of the normal squamocolumnar junction (SCJ) is often described as serrated with short projections of columnar mucosa that extend into the esophagus. As studies of the normal SCJ are sparse, the aim of this study was to test the hypothesis that the normal SCJ is even and that irregularities are manifestations of acid reflux. Fifty asymptomatic subjects and 149 patients with symptoms suggestive of gastroesophageal reflux disease underwent endoscopy and 48-h pH monitoring with a pH electrode positioned immediately above the SCJ. The shape of the SCJ was assessed according to the Z-line appearance classification and correlated with clinical characteristics and the degree of esophageal acid exposure in the most distal esophagus. Even SCJs without irregularities were significantly more common in asymptomatic subjects compared with patients (50% versus 10%, p acid exposure in individuals with an even SCJ was within normal limits. With increasing degree of irregularity of the SCJ, the frequency and duration of reflux episodes, the degree of distal esophageal acid exposure, and the prevalence of abnormal acid exposure increased progressively and significantly. The shape of the normal SCJ is even and also minimal irregularities are a consequence of acid reflux, likely due to the formation of small areas of metaplastic columnar mucosa.

  17. Research on making reactor buildings of irregular plan and elevation forms aseismatic

    International Nuclear Information System (INIS)

    Okawa, Izuru; Yamauchi, Yasuyuki

    1997-01-01

    The necessity of pursuing the possibility of irregular form buildings as the condition of location for construction is limited, and the rational and economical arrangement of equipment and piping is considered. In order to know the effect that irregular forms exert to the aseismatic ability of buildings, it is indispensable to develop the program for precision three-dimensional elastoplastic analysis at the time of earthquakes. As the means of solving the problem, the introduction of seismic insulation structure is conceivable. The investigation of seismic insulator and its modeling and the analysis of earthquake response were carried out, and the irregular form and the effect of seismic insulation were investigated, and the results of vibration test using test specimens were summarized. The concrete items of investigation were the characteristics of input earthquake motion, the techniques of analysis, the parametric study taking the input and various characteristics of buildings in consideration, and the synthetic assessment. The vibration table experiment and the static loading experiment for the purpose of grasping the response behavior in the case of irregular form of wall type and seismic insulation type structures were carried out, and the results are reported. (K.I.)

  18. Influence of the Wenchuan earthquake on self-reported irregular menstrual cycles in surviving women.

    Science.gov (United States)

    Li, Xiao-Hong; Qin, Lang; Hu, Han; Luo, Shan; Li, Lei; Fan, Wei; Xiao, Zhun; Li, Ying-Xing; Li, Shang-Wei

    2011-09-01

    To explore the influence of stress induced by the Wenchuan earthquake on the menstrual cycles of surviving women. Self-reports of the menstrual cycles of 473 women that survived the Wenchuan earthquake were analyzed. Menstrual regularity was defined as menses between 21 and 35 days long. The death of a child or the loss of property and social resources was verified for all surviving women. The severity of these losses was assessed and graded as high, little, and none. About 21% of the study participants reported that their menstrual cycles became irregular after the Wenchuan earthquake, and this percentage was significantly higher than before the earthquake (6%, p irregularity after the earthquake. Association analyses showed that some stressors of the Wenchuan earthquake were strongly associated with self-reports of menstrual irregularity, including the loss of children (RR: 1.58; 95% CI: 1.09, 2.28), large amounts of property (RR: 1.49; 95% CI: 1.03, 2.15), social resources (RR: 1.34; 95% CI: 1.00, 1.80) and the hormonal contraception use (RR: 1.62; 95% CI: 1.21, 1.83). Self-reported menstrual irregularity is common in women that survived the Wenchuan earthquake, especially in those who lost children, large amounts of property and social resources.

  19. Sensorimotor rhythm neurofeedback as adjunct therapy for Parkinson's disease.

    Science.gov (United States)

    Philippens, Ingrid H C H M; Wubben, Jacqueline A; Vanwersch, Raymond A P; Estevao, Dave L; Tass, Peter A

    2017-08-01

    Neurofeedback may enhance compensatory brain mechanisms. EEG-based sensorimotor rhythm neurofeedback training was suggested to be beneficial in Parkinson's disease. In a placebo-controlled study in parkinsonian nonhuman primates we here show that sensorimotor rhythm neurofeedback training reduces MPTP-induced parkinsonian symptoms and both ON and OFF scores during classical L-DOPA treatment. Our findings encourage further development of sensorimotor rhythm neurofeedback training as adjunct therapy for Parkinson's disease which might help reduce L-DOPA-induced side effects.

  20. Traffic dispersion through a series of signals with irregular split

    Science.gov (United States)

    Nagatani, Takashi

    2016-01-01

    We study the traffic behavior of a group of vehicles moving through a sequence of signals with irregular splits on a roadway. We present the stochastic model of vehicular traffic controlled by signals. The dynamic behavior of vehicular traffic is clarified by analyzing traffic pattern and travel time numerically. The group of vehicles breaks up more and more by the irregularity of signal's split. The traffic dispersion is induced by the irregular split. We show that the traffic dispersion depends highly on the cycle time and the strength of split's irregularity. Also, we study the traffic behavior through the series of signals at the green-wave strategy. The dependence of the travel time on offset time is derived for various values of cycle time. The region map of the traffic dispersion is shown in (cycle time, offset time)-space.

  1. Irregular Warfare: Impact on Future Professional Military Education

    National Research Council Canada - National Science Library

    Paschal, David G

    2006-01-01

    ... to operate effectively in an irregular warfare environment. The utility of a decisive war between nation states continues to decline and will eventually reach critical mass based upon the extreme imbalance of military power and a U.S. monopoly...

  2. Irregular Warfare: Special Operations Joint Professional Military Education Transformation

    National Research Council Canada - National Science Library

    Cannady, Bryan H

    2008-01-01

    ... on today's battlefront in Afghanistan and Iraq and in the Global War on Terrorism (GWOT). At the forefront of the GWOT and irregular warfare are the United States Special Operations Command (USSOCOM...

  3. Drug Intoxicated Irregular Fighters: Complications, Dangers, and Responses

    National Research Council Canada - National Science Library

    Kan, Paul R

    2008-01-01

    .... Drug consumption in contemporary wars has coincided with the use of child soldiers, has led to increased unpredictability among irregular fighters, provided the conditions for the breakdown of social...

  4. Justice: A Problem for Military Ethics during Irregular War

    National Research Council Canada - National Science Library

    Bauer, John W

    2008-01-01

    ... is?" or "Justice according to whom?" The relative nature of the term "justice" creates a problem for military ethics, particularly when soldiers try to determine what actions are morally acceptable when they are engaged in irregular warfare...

  5. Irregular Warfare: New Challenges for Civil-Military Relations

    National Research Council Canada - National Science Library

    Cronin, Patrick M

    2008-01-01

    .... Irregular warfare introduces new complications to what Eliot Cohen has called an unequal dialogue between civilian and military leaders in which civilian leaders hold the true power but must modulate...

  6. Role of parametric decay instabilities in generating ionospheric irregularities

    International Nuclear Information System (INIS)

    Kuo, S.P.; Cheo, B.R.; Lee, M.C.

    1983-01-01

    We show that purely growing instabilities driven by the saturation spectrum of parametric decay instabilities can produce a broad spectrum of ionospheric irregularities. The threshold field Vertical BarE/sub th/Vertical Bar of the instabilities decreases with the scale lengths lambda of the ionospheric irregularities as Vertical BarE/sub th/Vertical Barproportionallambda -2 in the small-scale range ( -2 with scale lengths larger than a few kilometers. The excitation of kilometer-scale irregularities is strictly restricted by the instabilities themselves and by the spatial inhomogeneity of the medium. These results are drawn from the analyses of four-wave interaction. Ion-neutral collisions impose no net effect on the instabilities when the excited ionospheric irregularities have a field-aligned nature

  7. Standing down Straight: Jump Rhythm Technique's Rhythm-Driven, Community-Directed Approach to Dance Education

    Science.gov (United States)

    Siegenfeld, Billy

    2009-01-01

    "Standing down straight" means to stand on two feet with both stability and relaxation. Using standing down straight as the foundation of class work, Jump Rhythm Technique offers a fresh alternative to conventional systems of dance study. It bases its pedagogy on three behaviors: grounding the body so that it can move with power and efficiency,…

  8. Edge irregular total labellings for graphs of linear size

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Miškuf, J.

    2009-01-01

    As an edge variant of the well-known irregularity strength of a graph G = (V, E) we investigate edge irregular total labellings, i.e. functions f : V ∪ E → {1, 2, ..., k} such that f (u) + f (u v) + f (v) ≠ f (u) + f (u v) + f (v) for every pair of different edges u v, u v ∈ E. The smallest possi...

  9. Speech rhythm analysis with decomposition of the amplitude envelope: characterizing rhythmic patterns within and across languages.

    Science.gov (United States)

    Tilsen, Sam; Arvaniti, Amalia

    2013-07-01

    This study presents a method for analyzing speech rhythm using empirical mode decomposition of the speech amplitude envelope, which allows for extraction and quantification of syllabic- and supra-syllabic time-scale components of the envelope. The method of empirical mode decomposition of a vocalic energy amplitude envelope is illustrated in detail, and several types of rhythm metrics derived from this method are presented. Spontaneous speech extracted from the Buckeye Corpus is used to assess the effect of utterance length on metrics, and it is shown how metrics representing variability in the supra-syllabic time-scale components of the envelope can be used to identify stretches of speech with targeted rhythmic characteristics. Furthermore, the envelope-based metrics are used to characterize cross-linguistic differences in speech rhythm in the UC San Diego Speech Lab corpus of English, German, Greek, Italian, Korean, and Spanish speech elicited in read sentences, read passages, and spontaneous speech. The envelope-based metrics exhibit significant effects of language and elicitation method that argue for a nuanced view of cross-linguistic rhythm patterns.

  10. Beat Keeping in a Sea Lion As Coupled Oscillation: Implications for Comparative Understanding of Human Rhythm.

    Science.gov (United States)

    Rouse, Andrew A; Cook, Peter F; Large, Edward W; Reichmuth, Colleen

    2016-01-01

    Human capacity for entraining movement to external rhythms-i.e., beat keeping-is ubiquitous, but its evolutionary history and neural underpinnings remain a mystery. Recent findings of entrainment to simple and complex rhythms in non-human animals pave the way for a novel comparative approach to assess the origins and mechanisms of rhythmic behavior. The most reliable non-human beat keeper to date is a California sea lion, Ronan, who was trained to match head movements to isochronous repeating stimuli and showed spontaneous generalization of this ability to novel tempos and to the complex rhythms of music. Does Ronan's performance rely on the same neural mechanisms as human rhythmic behavior? In the current study, we presented Ronan with simple rhythmic stimuli at novel tempos. On some trials, we introduced "perturbations," altering either tempo or phase in the middle of a presentation. Ronan quickly adjusted her behavior following all perturbations, recovering her consistent phase and tempo relationships to the stimulus within a few beats. Ronan's performance was consistent with predictions of mathematical models describing coupled oscillation: a model relying solely on phase coupling strongly matched her behavior, and the model was further improved with the addition of period coupling. These findings are the clearest evidence yet for parity in human and non-human beat keeping and support the view that the human ability to perceive and move in time to rhythm may be rooted in broadly conserved neural mechanisms.

  11. Circadian rhythm disruption as a link between Attention-Deficit/Hyperactivity Disorder and obesity?

    Science.gov (United States)

    Vogel, Suzan W N; Bijlenga, Denise; Tanke, Marjolein; Bron, Tannetje I; van der Heijden, Kristiaan B; Swaab, Hanna; Beekman, Aartjan T F; Kooij, J J Sandra

    2015-11-01

    Patients with Attention-Deficit/Hyperactivity Disorder (ADHD) have a high prevalence of obesity. This is the first study to investigate whether circadian rhythm disruption is a mechanism linking ADHD symptoms to obesity. ADHD symptoms and two manifestations of circadian rhythm disruption: sleep problems and an unstable eating pattern (skipping breakfast and binge eating later in the day) were assessed in participants with obesity (n= 114), controls (n= 154), and adult ADHD patients (n= 202). Participants with obesity had a higher prevalence of ADHD symptoms and short sleep on free days as compared to controls, but a lower prevalence of ADHD symptoms, short sleep on free days, and an unstable eating pattern as compared to ADHD patients.We found that participants with obesity had a similar prevalence rate of an unstable eating pattern when compared to controls. Moreover, mediation analyses showed that both sleep duration and an unstable eating pattern mediated the association between ADHD symptoms and body mass index (BMI). Our study supports the hypothesis that circadian rhythm disruption is a mechanism linking ADHD symptoms to obesity. Further research is needed to determine if treatment of ADHD and circadian rhythm disruption is effective in the prevention and treatment of obesity in patients with obesity and/or ADHD. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Design Optimization of Irregular Cellular Structure for Additive Manufacturing

    Science.gov (United States)

    Song, Guo-Hua; Jing, Shi-Kai; Zhao, Fang-Lei; Wang, Ye-Dong; Xing, Hao; Zhou, Jing-Tao

    2017-09-01

    Irregularcellular structurehas great potential to be considered in light-weight design field. However, the research on optimizing irregular cellular structures has not yet been reporteddue to the difficulties in their modeling technology. Based on the variable density topology optimization theory, an efficient method for optimizing the topology of irregular cellular structures fabricated through additive manufacturing processes is proposed. The proposed method utilizes tangent circles to automatically generate the main outline of irregular cellular structure. The topological layoutof each cellstructure is optimized using the relative density informationobtained from the proposed modified SIMP method. A mapping relationship between cell structure and relative densityelement is builtto determine the diameter of each cell structure. The results show that the irregular cellular structure can be optimized with the proposed method. The results of simulation and experimental test are similar for irregular cellular structure, which indicate that the maximum deformation value obtained using the modified Solid Isotropic Microstructures with Penalization (SIMP) approach is lower 5.4×10-5 mm than that using the SIMP approach under the same under the same external load. The proposed research provides the instruction to design the other irregular cellular structure.

  13. Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding

    Science.gov (United States)

    Harada, Y.; Gurnett, D. A.; Kopf, A. J.; Halekas, J. S.; Ruhunusiri, S.

    2018-01-01

    The upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off-vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars.

  14. Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

    Science.gov (United States)

    Thomas, Abey E.

    2018-05-01

    Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

  15. Fatigue damage estimation using irregularity factor. First report, irregularity factor calculations for narrow and broadband random time histories

    Science.gov (United States)

    Susuki, I.

    1981-11-01

    The results of an analysis of the irregularity factors of stationary and Gaussian random processes which are generated by filtering the output of a pure or a band-limited white noise are presented. An ideal band pass filter, a trapezoidal filter, and a Butterworth type band pass filter were examined. It was found that the values of the irregularity factors were approximately equal among these filters if only the end-slopes were the same rates. As the band width of filters increases, irregularity factors increase monotonically and approach the respective constant values depending on the end-slopes. This implies that the noise characteristics relevant to the fatigue damage such as statistical aspects of the height of the rise and fall or the distribution of the peak values are not changed for a broad band random time history. It was also found that the effect of band limitation of input white noise on irregularity factors is negligibly small.

  16. The Long War Concept: Using the Security Cooperation Marine Air Ground Task Force to Address Irregular Threats through Shaping and Deterrence

    National Research Council Canada - National Science Library

    Ziegler, Thomas

    2008-01-01

    .... As the nation comes to grips with the momentous task of combating terrorism and other irregular threats in the Long War, it must continually assess the effectiveness of foreign policy, and especially...

  17. Chaos control applied to heart rhythm dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Borem Ferreira, Bianca, E-mail: biaborem@gmail.com [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil); Souza de Paula, Aline, E-mail: alinedepaula@unb.br [Universidade de Brasi' lia, Department of Mechanical Engineering, 70.910.900 Brasilia, DF (Brazil); Amorim Savi, Marcelo, E-mail: savi@mecanica.ufrj.br [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil)

    2011-08-15

    Highlights: > A natural cardiac pacemaker is modeled by a modified Van der Pol oscillator. > Responses related to normal and chaotic, pathological functioning of the heart are investigated. > Chaos control methods are applied to avoid pathological behaviors of heart dynamics. > Different approaches are treated: stabilization of unstable periodic orbits and chaos suppression. - Abstract: The dynamics of cardiovascular rhythms have been widely studied due to the key aspects of the heart in the physiology of living beings. Cardiac rhythms can be either periodic or chaotic, being respectively related to normal and pathological physiological functioning. In this regard, chaos control methods may be useful to promote the stabilization of unstable periodic orbits using small perturbations. In this article, the extended time-delayed feedback control method is applied to a natural cardiac pacemaker described by a mathematical model. The model consists of a modified Van der Pol equation that reproduces the behavior of this pacemaker. Results show the ability of the chaos control strategy to control the system response performing either the stabilization of unstable periodic orbits or the suppression of chaotic response, avoiding behaviors associated with critical cardiac pathologies.

  18. Circadian rhythm and its role in malignancy

    Directory of Open Access Journals (Sweden)

    Mahmood Saqib

    2010-03-01

    Full Text Available Abstract Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation extends beyond clock genes to involve various clock-controlled genes (CCGs including various cell cycle genes. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic approaches for treating circadian-related disorders, especially cancer.

  19. Turn exchange rhythm in English dialogues

    Science.gov (United States)

    Fon, Janice

    2005-09-01

    This study looked at the relationship between rhythm and exchange type in British English, a stress-timed language, and Singaporean English, a syllable-timed language, using a spontaneous speech corpus. Exchange intervals (EIs), or the time difference between the end of one speaker and the beginning of another, were measured and exchanges of different types were labeled. Results showed that, in a dialogue, EIs were generally limited to a narrow range. However, within this range, EIs had at least four functions. First, EIs were reflective of the cognitive load and functioned as a way to differentiate various exchange types. Those requiring more cognitive resources, such as question-and-answer pairs, generally needed longer EIs than those not as cognitively loaded, such as backchanneling pairs. Second, EIs were indicative of linguistic rhythm. Singaporean English tended to have shorter EIs than British English. Third, EIs were reflective of politeness. The degree of politeness correlated negatively with EI. Shorter EIs showed a higher degree of respect. Finally, EIs were also indicative of the level of insecurity of a speaker, which was best reflected by gender differences. Females in general had longer EIs than males.

  20. Temperature compensation and entrainment in circadian rhythms

    International Nuclear Information System (INIS)

    Bodenstein, C; Heiland, I; Schuster, S

    2012-01-01

    To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24 h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles. (paper)

  1. Strength of Gamma Rhythm Depends on Normalization

    Science.gov (United States)

    Ray, Supratim; Ni, Amy M.; Maunsell, John H. R.

    2013-01-01

    Neuronal assemblies often exhibit stimulus-induced rhythmic activity in the gamma range (30–80 Hz), whose magnitude depends on the attentional load. This has led to the suggestion that gamma rhythms form dynamic communication channels across cortical areas processing the features of behaviorally relevant stimuli. Recently, attention has been linked to a normalization mechanism, in which the response of a neuron is suppressed (normalized) by the overall activity of a large pool of neighboring neurons. In this model, attention increases the excitatory drive received by the neuron, which in turn also increases the strength of normalization, thereby changing the balance of excitation and inhibition. Recent studies have shown that gamma power also depends on such excitatory–inhibitory interactions. Could modulation in gamma power during an attention task be a reflection of the changes in the underlying excitation–inhibition interactions? By manipulating the normalization strength independent of attentional load in macaque monkeys, we show that gamma power increases with increasing normalization, even when the attentional load is fixed. Further, manipulations of attention that increase normalization increase gamma power, even when they decrease the firing rate. Thus, gamma rhythms could be a reflection of changes in the relative strengths of excitation and normalization rather than playing a functional role in communication or control. PMID:23393427

  2. Circadian Rhythms, Sleep Deprivation, and Human Performance

    Science.gov (United States)

    Goel, Namni; Basner, Mathias; Rao, Hengyi; Dinges, David F.

    2014-01-01

    Much of the current science on, and mathematical modeling of, dynamic changes in human performance within and between days is dominated by the two-process model of sleep–wake regulation, which posits a neurobiological drive for sleep that varies homeostatically (increasing as a saturating exponential during wakefulness and decreasing in a like manner during sleep), and a circadian process that neurobiologically modulates both the homeostatic drive for sleep and waking alertness and performance. Endogenous circadian rhythms in neurobehavioral functions, including physiological alertness and cognitive performance, have been demonstrated using special laboratory protocols that reveal the interaction of the biological clock with the sleep homeostatic drive. Individual differences in circadian rhythms and genetic and other components underlying such differences also influence waking neurobehavioral functions. Both acute total sleep deprivation and chronic sleep restriction increase homeostatic sleep drive and degrade waking neurobehavioral functions as reflected in sleepiness, attention, cognitive speed, and memory. Recent evidence indicating a high degree of stability in neurobehavioral responses to sleep loss suggests that these trait-like individual differences are phenotypic and likely involve genetic components, including circadian genes. Recent experiments have revealed both sleep homeostatic and circadian effects on brain metabolism and neural activation. Investigation of the neural and genetic mechanisms underlying the dynamically complex interaction between sleep homeostasis and circadian systems is beginning. A key goal of this work is to identify biomarkers that accurately predict human performance in situations in which the circadian and sleep homeostatic systems are perturbed. PMID:23899598

  3. Rhythms of EEG and cognitive processes

    Directory of Open Access Journals (Sweden)

    Novikova S.I.

    2015-06-01

    Full Text Available The study of cognitive processes is regarded to be more effective if it combines a psychological approach with a neurophysiological one. This approach makes it possible to come closer to understanding of the basic mechanisms of different cognitive processes, to describe the patterns of forming these mechanisms in ontogenesis, to investigate the origin of cognitive impairments, and to develop intervention techniques. The promising way of investigating the mechanisms of cognitive functions is the electroencephalography (EEG. This is a non-invasive, safe, and relatively cheap method of research of the functional condition of the brain. The characteristics of EEG rhythms, recorded with different cognitive loads, reflect the processes of functional modulation of neural network activity of the cortex, which serves the neurophysiologic basis for attention, memory and other cognitive processes. The article provides an overview of works containing the analysis of the alpha and theta rhythms’ dynamics in various states of wakefulness. It also introduces the substantiation of methodology of functional regulatory approach to the interpretation of behaviors of EEG rhythms.

  4. A circadian rhythm regulating hyphal melanization in Cercospora kikuchii.

    Science.gov (United States)

    Bluhm, Burton H; Burnham, A Michele; Dunkle, Larry D

    2010-01-01

    Many metabolic and developmental processes in fungi are controlled by biological rhythms. Circadian rhythms approximate a daily (24 h) cycle and have been thoroughly studied in the model fungus, Neurospora crassa. However relatively few examples of true circadian rhythms have been documented among other filamentous fungi. In this study we describe a circadian rhythm underlying hyphal melanization in Cercospora kikuchii, an important pathogen of soybean. After growth in light or light : dark cycles, colonies transferred to darkness produced zonate bands of melanized hyphae interspersed with bands of hyaline hyphae. Rhythmic production of bands was remarkably persistent in the absence of external cues, lasting at least 7 d after transfer to darkness, and was compensated over a range of temperatures. As in N. crassa, blue light but not red light was sufficient to entrain the circadian rhythm in C. kikuchii, and a putative ortholog of white collar-1, one of the genes required for light responses in N. crassa, was identified in C. kikuchii. Circadian regulation of melanization is conserved in other members of the genus: Similar rhythms were identified in another field isolate of C. kikuchii as well as field isolates of C. beticola and C. sorghi, but not in wild-type strains of C. zeae-maydis or C. zeina. This report represents the first documented circadian rhythm among Dothideomycete fungi and provides a new opportunity to dissect the molecular basis of circadian rhythms among filamentous fungi.

  5. Effects of Some Aspects of Rhythm on Tempo Perception.

    Science.gov (United States)

    Wang, Cecilia Chu

    1984-01-01

    Results indicated that significantly more time is needed to perceive tempo increase than tempo decrease, uneven rhythm then even rhythm, and melody alone than melody with accompaniment. Furthermore, significant interaction effects involving beat locations of tempo change suggest that differential groupings may be a factor in tempo discrimination.…

  6. Effects of tempo and timing of simple musical rhythms

    NARCIS (Netherlands)

    Repp, B.H.; Windsor, W.L.; Desain, P.W.M.

    2002-01-01

    In this study we investigated whether and how the timing of musical rhythms changes with tempo. Twelve skilled pianists played a monophonic 8-bar melody in 21 different rhythmic versions at 4 different tempi. Within bars, the rhythms represented all possible ordered pairs and triplets of note values

  7. A Circadian Rhythm Regulating Hyphal Melanization in Cercospora Kikuchii

    Science.gov (United States)

    Circadian rhythms, biochemical or developmental processes with a period length of approximately 24 hours, are thoroughly documented in plants and animals. However, virtually all of what is currently known about circadian rhythms in fungi is derived from the model fungus, Neurospora crassa, including...

  8. A novel animal model linking adiposity to altered circadian rhythms

    Science.gov (United States)

    Researchers have provided evidence for a link between obesity and altered circadian rhythms (e.g., shift work, disrupted sleep), but the mechanism for this association is still unknown. Adipocytes possess an intrinsic circadian clock, and circadian rhythms in adipocytokines and adipose tissue metab...

  9. Circadian Activity Rhythms, Time Urgency, and Achievement Concerns.

    Science.gov (United States)

    Watts, Barbara L.

    Many physiological and psychological processes fluctuate throughout the day in fairly stable, rhythmic patterns. The relationship between individual differences in circadian activity rhythms and a sense of time urgency were explored as well as a number of achievement-related variables. Undergraduates (N=308), whose circadian activity rhythms were…

  10. Interactive Rhythm Learning System by Combining Tablet Computers and Robots

    Directory of Open Access Journals (Sweden)

    Chien-Hsing Chou

    2017-03-01

    Full Text Available This study proposes a percussion learning device that combines tablet computers and robots. This device comprises two systems: a rhythm teaching system, in which users can compose and practice rhythms by using a tablet computer, and a robot performance system. First, teachers compose the rhythm training contents on the tablet computer. Then, the learners practice these percussion exercises by using the tablet computer and a small drum set. The teaching system provides a new and user-friendly score editing interface for composing a rhythm exercise. It also provides a rhythm rating function to facilitate percussion training for children and improve the stability of rhythmic beating. To encourage children to practice percussion exercises, a robotic performance system is used to interact with the children; this system can perform percussion exercises for students to listen to and then help them practice the exercise. This interaction enhances children’s interest and motivation to learn and practice rhythm exercises. The results of experimental course and field trials reveal that the proposed system not only increases students’ interest and efficiency in learning but also helps them in understanding musical rhythms through interaction and composing simple rhythms.

  11. Unexpected diversity in socially synchronized rhythms of shorebirds

    NARCIS (Netherlands)

    Bulla, Martin; Valcu, Mihai; Dokter, Adriaan M; Dondua, Alexei G; Kosztolányi, András; Helm, Barbara; Sandercock, Brett K; Casler, Bruce; Ens, Bruno J.; Spiegel, Caleb S; Hassell, Chris J; Küpper, Clemens; Minton, Clive; Burgas, Daniel; Lank, David B; Payer, David C; Loktionov, Egor Y; Nol, Erica; Kwon, Eunbi; Smith, Fletcher; Gates, H River; Vitnerová, Hana; Prüter, Hanna; Johnson, James A; St Clair, James J H; Lamarre, Jean-François; Rausch, Jennie; Reneerkens, Jeroen; Conklin, Jesse R; Burger, Joanna; Liebezeit, Joe; Bêty, Joël; Coleman, Jonathan T; Figuerola, Jordi; Hooijmeijer, Joslyn; Alves, José A; Smith, Joseph A M; Weidinger, Karel; Koivula, Kari; Gosbell, Ken; Exo, Klaus-Michael; Niles, Larry; Koloski, Laura; McKinnon, Laura; Praus, Libor; Klaassen, Marcel; Giroux, Marie-Andrée; Sládeček, Martin; Boldenow, Megan L; Goldstein, Michael I; Šálek, Miroslav; Senner, Nathan; Rönkä, Nelli; Lecomte, Nicolas; Gilg, Olivier; Vincze, Orsolya; Johnson, Oscar W; Smith, Paul A; Woodard, Paul F; Tomkovich, Pavel S; Battley, Phil F; Bentzen, Rebecca; Lanctot, Richard B; Porter, Ron; Saalfeld, Sarah T; Freeman, Scott; Brown, Stephen C; Yezerinac, Stephen; Székely, Tamás; Montalvo, Tomás; Piersma, Theunis; Loverti, Vanessa; Pakanen, Veli-Matti; Tijsen, Wim; Kempenaers, Bart

    2016-01-01

    The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities

  12. The evolution of rhythm cognition: Timing in music and speech

    NARCIS (Netherlands)

    Ravignani, A.; Honing, H.; Kotz, S.A.

    This editorial serves a number of purposes. First, it aims at summarizing and discussing 33 accepted contributions to the special issue ‘The evolution of rhythm cognition: Timing in music and speech’. The major focus of the issue is the cognitive neuroscience of rhythm, intended as a neurobehavioral

  13. Interaction with Mass Media: The Importance of Rhythm and Tempo.

    Science.gov (United States)

    Snow, Robert P.

    1987-01-01

    Stresses that understanding the impact of interaction with mass media requires conceptualizing media as an institutionalized social form. A critical feature of this process is the grammatical character of media interaction in the form of rhythm and tempo, because these rhythms and tempos become established in everyday routine. (SKC)

  14. Orbital and Collisional Evolution of the Irregular Satellites

    Science.gov (United States)

    Nesvorný, David; Alvarellos, Jose L. A.; Dones, Luke; Levison, Harold F.

    2003-07-01

    The irregular moons of the Jovian planets are a puzzling part of the solar system inventory. Unlike regular satellites, the irregular moons revolve around planets at large distances in tilted and eccentric orbits. Their origin, which is intimately linked with the origin of the planets themselves, is yet to be explained. Here we report a study of the orbital and collisional evolution of the irregular satellites from times after their formation to the present epoch. The purpose of this study is to find out the features of the observed irregular moons that can be attributed to this evolution and separate them from signatures of the formation process. We numerically integrated ~60,000 test satellite orbits to map orbital locations that are stable on long time intervals. We found that the orbits highly inclined to the ecliptic are unstable due to the effect of the Kozai resonance, which radially stretches them so that satellites either escape from the Hill sphere, collide with massive inner moons, or impact the parent planet. We also found that prograde satellite orbits with large semimajor axes are unstable due to the effect of the evection resonance, which locks the orbit's apocenter to the apparent motion of the Sun around the parent planet. In such a resonance, the effect of solar tides on a resonant moon accumulates at each apocenter passage of the moon, which causes a radially outward drift of its orbital apocenter; once close to the Hill sphere, the moon escapes. By contrast, retrograde moons with large orbital semimajor axes are long-lived. We have developed an analytic model of the distant satellite orbits and used it to explain the results of our numerical experiments. In particular, we analytically studied the effect of the Kozai resonance. We numerically integrated the orbits of the 50 irregular moons (known by 2002 August 16) for 108 yr. All orbits were stable on this time interval and did not show any macroscopic variations that would indicate

  15. Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion.

    Science.gov (United States)

    Kato, Katsuya; Gemba, Kenichi; Fujimoto, Nobukazu; Aoe, Keisuke; Takeshima, Yukio; Inai, Kouki; Kishimoto, Takumi

    2016-09-01

    To elucidate differences in the level and localization of pleural irregularities in early malignant pleural mesothelioma (eMPM) and benign asbestos pleural effusion (BAPE) using CT. Retrospective assessment of CT findings of consecutive patients with BAPE at a single centre and patients with eMPM reported in Japanese vital statistics. Thirty-six patients with confirmed diagnoses of BAPE and sixty-six patients with confirmed diagnoses of eMPM (mesothelioma stages T1 or T2) were included. Informed consent, CT scans, and clinical and pathologic details were obtained for all patients and were reviewed by one radiologist, two pathologists, and two pulmonologists. Asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening were assessed in all patients. Prevalence of asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening was significantly higher in the BAPE group. Low-level irregularity was more common in the BAPE group (ppleural irregularity was not observed in any patients in the BAPE group, although 55% of patients in the eMPM group showed interlobar pleural irregularity. Mediastinal pleural involvement was observed in 74% of patients in the eMPM group and had a positive predictive value of 89%. This study demonstrates that the level and localization of plural irregularities significantly differed between patients with BAPE and eMPM. Large-scale prospective studies are needed to fully establish the diagnostic utility of such differences. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. THE MEASUREMENT METHODOLOGY IMPROVEMENT OF THE HORIZONTAL IRREGULARITIES IN PLAN

    Directory of Open Access Journals (Sweden)

    O. M. Patlasov

    2015-08-01

    Full Text Available Purpose. Across the track superstructure (TSS there are structures where standard approach to the decision on the future of their operation is not entirely correct or acceptable. In particular, it concerns the track sections which are sufficiently quickly change their geometric parameters: the radius of curvature, angle of rotation, and the like. As an example, such portions of TSS may include crossovers where their component is within the so-called connecting part, which at a sufficiently short length, substantially changes curvature. The estimation of the position in terms of a design on the basis of the existing technique (by the difference in the adjacent arrows bending is virtually impossible. Therefore it is proposed to complement and improve the methodology for assessing the situation of the curve in plan upon difference in the adjacent versine. Methodology. The possible options for measuring horizontal curves in the plan were analyzed. The most adequate method, which does not contradict existing on the criterion of the possibility of using established standards was determined. The ease of measurement and calculation was took into account. Findings. Qualitative and quantitative verification of the proposed and existing methods showed very good agreement of the measurement results. This gives grounds to assert that this methodology can be recommended to the workers of track facilities in the assessment of horizontal irregularities in plan not only curves, but also within the connecting part of switch congresses. Originality. The existing method of valuation of the geometric position of the curves in the plan was improved. It does not create new regulations, and all results are evaluated by existing norms. Practical value. The proposed technique makes it possible, without creating a new regulatory framework, to be attached to existing one, and expanding the boundaries of its application. This method can be used not only for ordinary curves

  17. Automatic evaluation of speech rhythm instability and acceleration in dysarthrias associated with basal ganglia dysfunction

    Directory of Open Access Journals (Sweden)

    Jan eRusz

    2015-07-01

    Full Text Available Speech rhythm abnormalities are commonly present in patients with different neurodegenerative disorders. These alterations are hypothesized to be a consequence of disruption to the basal ganglia circuitry involving dysfunction of motor planning, programming and execution, which can be detected by a syllable repetition paradigm. Therefore, the aim of the present study was to design a robust signal processing technique that allows the automatic detection of spectrally-distinctive nuclei of syllable vocalizations and to determine speech features that represent rhythm instability and acceleration. A further aim was to elucidate specific patterns of dysrhythmia across various neurodegenerative disorders that share disruption of basal ganglia function. Speech samples based on repetition of the syllable /pa/ at a self-determined steady pace were acquired from 109 subjects, including 22 with Parkinson's disease (PD, 11 progressive supranuclear palsy (PSP, 9 multiple system atrophy (MSA, 24 ephedrone-induced parkinsonism (EP, 20 Huntington's disease (HD, and 23 healthy controls. Subsequently, an algorithm for the automatic detection of syllables as well as features representing rhythm instability and rhythm acceleration were designed. The proposed detection algorithm was able to correctly identify syllables and remove erroneous detections due to excessive inspiration and nonspeech sounds with a very high accuracy of 99.6%. Instability of vocal pace performance was observed in PSP, MSA, EP and HD groups. Significantly increased pace acceleration was observed only in the PD group. Although not significant, a tendency for pace acceleration was observed also in the PSP and MSA groups. Our findings underline the crucial role of the basal ganglia in the execution and maintenance of automatic speech motor sequences. We envisage the current approach to become the first step towards the development of acoustic technologies allowing automated assessment of rhythm

  18. Parkinsonian syndromes presenting with circadian rhythm sleep disorder- advanced sleep-phase type.

    Science.gov (United States)

    Shukla, Garima; Kaul, Bhavna; Gupta, Anupama; Goyal, Vinay; Behari, Madhuri

    2015-01-01

    Circadian rhythm sleep disorder-advanced sleep-phase type is a relatively uncommon disorder, mostly seen among the elderly population. Impaired circadian rhythms have been reported in neurodegenerative conditions; however, there are no reports of any circadian rhythm sleep disorder among patients with Parkinsonian syndromes. We report two patients who presented with this circadian rhythm disorder, and were then diagnosed with a Parkinsonian syndrome. The cases. A 65-year-old retired man presented with history of abrupt change in sleep schedules, sleeping around 6.30-7 p.m. and waking up around 3-4 a.m. for the last 2 months. On detailed examination, the patient was observed to have symmetrical bradykinesia and cogwheel rigidity of limbs. A diagnosis of multiple system atrophy was made, supported by MRI findings and evidence of autonomic dysfunction. Symptoms of change in sleep-wake cycles resolved over the next 1 year, while the patient was treated with dopaminergic therapy. A 47-year-old man, who was being evaluated for presurgical investigation for refractory temporal lobe epilepsy, presented with complaints suggestive of dysarthria, bradykinesia of limbs and frequent falls for 5 months. Simultaneously, he began to sleep around 7 p.m. and wake up at about 2-3 a.m. Examination revealed severe axial rigidity, restricted vertical gaze and bradykinesia of limbs. A diagnosis of progressive supranuclear palsy was made. This is the first report of Parkinson's plus syndromes presenting with a circadian rhythm sleep disorder-advanced sleep-phase type. More prospective assessment for circadian sleep disorders may introduce useful insights into similar associations. Copyright 2015, NMJI.

  19. Development and Evaluation of a Smartphone-Based Measure of Social Rhythms for Bipolar Disorder.

    Science.gov (United States)

    Matthews, Mark; Abdullah, Saeed; Murnane, Elizabeth; Voida, Stephen; Choudhury, Tanzeem; Gay, Geri; Frank, Ellen

    2016-08-01

    Dynamic psychological processes are most often assessed using self-report instruments. This places a constraint on how often and for how long data can be collected due to the burden placed on human participants. Smartphones are ubiquitous and highly personal devices, equipped with sensors that offer an opportunity to measure and understand psychological processes in real-world contexts over the long term. In this article, we present a novel smartphone approach to address the limitations of self-report in bipolar disorder where mood and activity are key constructs. We describe the development of MoodRhythm, a smartphone application that incorporates existing self-report elements from interpersonal and social rhythm therapy, a clinically validated treatment, and combines them with novel inputs from smartphone sensors. We reflect on lessons learned in transitioning from an existing self-report instrument to one that involves smartphone sensors and discuss the potential impact of these changes on the future of psychological assessment.

  20. Geostatistical regularization operators for geophysical inverse problems on irregular meshes

    Science.gov (United States)

    Jordi, C.; Doetsch, J.; Günther, T.; Schmelzbach, C.; Robertsson, J. OA

    2018-05-01

    Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.

  1. Total edge irregularity strength of (n,t)-kite graph

    Science.gov (United States)

    Winarsih, Tri; Indriati, Diari

    2018-04-01

    Let G(V, E) be a simple, connected, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ :V(G)\\cup E(G)\\to \\{1,2,\\ldots,k\\} of a graph G is a labeling of vertices and edges of G in such a way that for any different edges e and f, weights wt(e) and wt(f) are distinct. The weight wt(e) of an edge e = xy is the sum of the labels of vertices x and y and the label of the edge e. The total edge irregularity strength of G, tes(G), is defined as the minimum k for which a graph G has an edge irregular total k-labeling. An (n, t)-kite graph consist of a cycle of length n with a t-edge path (the tail) attached to one vertex of a cycle. In this paper, we investigate the total edge irregularity strength of the (n, t)-kite graph, with n > 3 and t > 1. We obtain the total edge irregularity strength of the (n, t)-kite graph is tes((n, t)-kite) = \\lceil \\frac{n+t+2}{3}\\rceil .

  2. Irregular or absent periods--what can an ultrasound scan tell you?

    Science.gov (United States)

    Khalid, Asma

    2004-02-01

    Transvaginal ultrasonography has increased our appreciation of the physiological changes in the ovary and endometrium that occur during the normal menstrual cycle. It has become a primary investigative tool in women with irregular or absent periods. Its usefulness in cases of primary amenorrhoea to assess anatomy is also undisputed although it may have limitations in terms of its specificity. However, the interpretation of ultrasound images in women with irregular menses or secondary amenorrhoea is not entirely straightforward. This is particularly true in the diagnosis of polycystic ovary syndrome, a condition of uncertain aetiology, which may present with oligoamenorrhoea. This chapter aims to discuss the benefits and limitations of ultrasound while taking into account the broad overlap between normal and abnormal physiology, some of which has still to be elucidated.

  3. Ovarian markers and irregular menses among women with type 1 diabetes in the Epidemiology of Diabetes Interventions and Complications study.

    Science.gov (United States)

    Kim, C; Miller, R S; Braffett, B H; Pan, Y; Arends, V L; Saenger, A K; Barnie, A; Sarma, A V

    2018-03-01

    Women with type 1 diabetes have increased risk of infertility compared to women without diabetes even after adjustment for irregular menses, but aetiologies are incompletely understood. Our aim was to examine the prevalence of abnormalities in ovarian markers consistent with polycystic ovary syndrome in women with type 1 diabetes and associations with irregular menses and diabetes-specific variables. We conducted a secondary analysis of women in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC), a randomized trial and observational follow-up of intensive insulin therapy for type 1 diabetes. We included women with anti-Müllerian hormone (AMH) measurements among women not using oral contraceptives (n = 187). Initial AMH and testosterone measures were performed between EDIC years 1 and 4. History of irregular menses was assessed annually. The median age of women was 35 (interquartile ratio 29, 40) years; 133 (35%) had elevated AMH and 62 (17%) reported irregular menses. Twelve per cent of women had relative elevations in total testosterone. In multivariable models, lower insulin dosages were associated with higher AMH concentrations (P = .0027), but not diabetes duration, glycemic control, body mass index or irregular menses. Neither irregular menses nor diabetes-specific variables were associated with testosterone concentrations. Among women with type 1 diabetes in their thirties, abnormalities in ovarian markers are common and not associated with irregular menses and thus may partially account for decreased fecundity in women with type 1 diabetes. © 2018 John Wiley & Sons Ltd.

  4. Circadian Rhythms, Sleep, and Disorders of Aging.

    Science.gov (United States)

    Mattis, Joanna; Sehgal, Amita

    2016-04-01

    Sleep-wake cycles are known to be disrupted in people with neurodegenerative disorders. These findings are now supported by data from animal models for some of these disorders, raising the question of whether the disrupted sleep/circadian regulation contributes to the loss of neural function. As circadian rhythms and sleep consolidation also break down with normal aging, changes in these may be part of what makes aging a risk factor for disorders like Alzheimer's disease (AD). Mechanisms underlying the connection between circadian/sleep dysregulation and neurodegeneration remain unclear, but several recent studies provide interesting possibilities. While mechanistic analysis is under way, it is worth considering treatment of circadian/sleep disruption as a means to alleviate symptoms of neurodegenerative disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Choreographing Compassion: A Clinical Adventure of Rhythms.

    Science.gov (United States)

    Yopst, Charles George

    2015-06-01

    Compassion is a primary catalyst motivating positive human relationships, especially of those less fortunate. Our rhythms Expand-Contract of our own non-verbal body joints movements and of the law of counter-balance, enable us to identify which of nine innate affects-emotions is directing the body's movements. With this reading, a trained person can synchronize choreography of these into fully authentic compassion between two or more persons. Primary references for this are the late Silvan S. Tomkins's four volumes "Affect Imagery Consciousness," and choreographers the late Rudolf Laban, Warren Lamb, Irmgard Bartenieff, and Marian Chace. Professionals, clinicians, and laity counselors can all use these. © The Author(s) 2015.

  6. Effect of Pilates Training on Alpha Rhythm

    Directory of Open Access Journals (Sweden)

    Zhijie Bian

    2013-01-01

    Full Text Available In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI. It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation.

  7. Effect of Pilates Training on Alpha Rhythm

    Science.gov (United States)

    Bian, Zhijie; Sun, Hongmin; Lu, Chengbiao; Yao, Li; Chen, Shengyong; Li, Xiaoli

    2013-01-01

    In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI). It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation. PMID:23861723

  8. Sensorimotor Rhythm Neurofeedback Enhances Golf Putting Performance.

    Science.gov (United States)

    Cheng, Ming-Yang; Huang, Chung-Ju; Chang, Yu-Kai; Koester, Dirk; Schack, Thomas; Hung, Tsung-Min

    2015-12-01

    Sensorimotor rhythm (SMR) activity has been related to automaticity during skilled action execution. However, few studies have bridged the causal link between SMR activity and sports performance. This study investigated the effect of SMR neurofeedback training (SMR NFT) on golf putting performance. We hypothesized that preelite golfers would exhibit enhanced putting performance after SMR NFT. Sixteen preelite golfers were recruited and randomly assigned into either an SMR or a control group. Participants were asked to perform putting while electroencephalogram (EEG) was recorded, both before and after intervention. Our results showed that the SMR group performed more accurately when putting and exhibited greater SMR power than the control group after 8 intervention sessions. This study concludes that SMR NFT is effective for increasing SMR during action preparation and for enhancing golf putting performance. Moreover, greater SMR activity might be an EEG signature of improved attention processing, which induces superior putting performance.

  9. Clinical learning environments: place, artefacts and rhythm.

    Science.gov (United States)

    Sheehan, Dale; Jowsey, Tanisha; Parwaiz, Mariam; Birch, Mark; Seaton, Philippa; Shaw, Susan; Duggan, Alison; Wilkinson, Tim

    2017-10-01

    Health care practitioners learn through experience in clinical environments in which supervision is a key component, but how that learning occurs outside the supervision relationship remains largely unknown. This study explores the environmental factors that inform and support workplace learning within a clinical environment. An observational study drawing on ethnographic methods was undertaken in a general medicine ward. Observers paid attention to interactions among staff members that involved potential teaching and learning moments that occurred and were visible in the course of routine work. General purpose thematic analysis of field notes was undertaken. A total of 376 observations were undertaken and documented. The findings suggest that place (location of interaction), rhythm (regularity of activities occurring in the ward) and artefacts (objects and equipment) were strong influences on the interactions and exchanges that occurred. Each of these themes had inherent tensions that could promote or inhibit engagement and therefore learning opportunities. Although many learning opportunities were available, not all were taken up or recognised by the participants. We describe and make explicit how the natural environment of a medical ward and flow of work through patient care contribute to the learning architecture, and how this creates or inhibits opportunities for learning. Awareness of learning opportunities was often tacit and not explicit for either supervisor or learner. We identify strategies through which tensions inherent within space, artefacts and the rhythms of work can be resolved and learning opportunities maximised. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  10. Circadian Rhythms in Diet-Induced Obesity.

    Science.gov (United States)

    Engin, Atilla

    2017-01-01

    The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in

  11. Biological and psychological rhythms: an integrative approach to rhythm disturbances in autistic disorder.

    Science.gov (United States)

    Botbol, Michel; Cabon, Philippe; Kermarrec, Solenn; Tordjman, Sylvie

    2013-09-01

    Biological rhythms are crucial phenomena that are perfect examples of the adaptation of organisms to their environment. A considerable amount of work has described different types of biological rhythms (from circadian to ultradian), individual differences in their patterns and the complexity of their regulation. In particular, the regulation and maturation of the sleep-wake cycle have been thoroughly studied. Its desynchronization, both endogenous and exogenous, is now well understood, as are its consequences for cognitive impairments and health problems. From a completely different perspective, psychoanalysts have shown a growing interest in the rhythms of psychic life. This interest extends beyond the original focus of psychoanalysis on dreams and the sleep-wake cycle, incorporating central theoretical and practical psychoanalytic issues related to the core functioning of the psychic life: the rhythmic structures of drive dynamics, intersubjective developmental processes and psychic containment functions. Psychopathological and biological approaches to the study of infantile autism reveal the importance of specific biological and psychological rhythmic disturbances in this disorder. Considering data and hypotheses from both perspectives, this paper proposes an integrative approach to the study of these rhythmic disturbances and offers an etiopathogenic hypothesis based on this integrative approach. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. On the Automatic Parallelization of Sparse and Irregular Fortran Programs

    Directory of Open Access Journals (Sweden)

    Yuan Lin

    1999-01-01

    Full Text Available Automatic parallelization is usually believed to be less effective at exploiting implicit parallelism in sparse/irregular programs than in their dense/regular counterparts. However, not much is really known because there have been few research reports on this topic. In this work, we have studied the possibility of using an automatic parallelizing compiler to detect the parallelism in sparse/irregular programs. The study with a collection of sparse/irregular programs led us to some common loop patterns. Based on these patterns new techniques were derived that produced good speedups when manually applied to our benchmark codes. More importantly, these parallelization methods can be implemented in a parallelizing compiler and can be applied automatically.

  13. Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

    International Nuclear Information System (INIS)

    Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

    2007-01-01

    A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

  14. NEOWISE: OBSERVATIONS OF THE IRREGULAR SATELLITES OF JUPITER AND SATURN

    Energy Technology Data Exchange (ETDEWEB)

    Grav, T. [Planetary Science Institute, Tucson, AZ 85719 (United States); Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Sonnett, S.; Kramer, E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Nugent, C. R.; Cutri, R. M., E-mail: tgrav@psi.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-08-10

    We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE data set. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer solar system, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.

  15. Bottomside sinusoidal irregularities in the equatorial F region

    Science.gov (United States)

    Valladares, C. E.; Hanson, W. B.; Mcclure, J. P.; Cragin, B. L.

    1983-01-01

    By using the Ogo 6 satellite, McClure and Hanson (1973) have discovered sinusoidal irregularities in the equatorial F region ion number density. In the present investigation, a description is provided of the properties of a distinct category of sinusoidal irregularities found in equatorial data from the AE-C and AE-E satellites. The observed scale sizes vary from about 300 m to 3 km in the direction perpendicular to B, overlapping with and extending the range observed by using Ogo 6. Attention is given to low and high resolution data, a comparison with Huancayo ionograms, the confinement of 'bottomside sinusoidal' (BSS) irregularities essentially to the bottomside of the F layer, spectral characteristics, and BSS, scintillation, and ionosonde observations.

  16. Irregular flowering patterns in terrestrial orchids: theories vs. empirical data

    Directory of Open Access Journals (Sweden)

    P. Kindlmann

    2001-11-01

    Full Text Available Empirical data on many species of terrestrial orchids suggest that their between-year flowering pattern is extremely irregular and unpredictable. A long search for the reason has hitherto proved inconclusive. Here we summarise and critically review the hypotheses that were put forward as explanations of this phenomenon: irregular flowering was attributed to costs associated with sexual reproduction, to herbivory, or to the chaotic behaviour of the system represented by difference equations describing growth of the vegetative and reproductive organs. None of these seems to explain fully the events of a transition from flowering one year to sterility or absence the next year. Data on the seasonal growth of leaves and inflorescence of two terrestrial orchid species, Epipactis albensis and Dactylorhiza fuchsii and our previous results are then used here to fill gaps in what has been published until now and to test alternative explanations of the irregular flowering patterns of orchids.

  17. Track Irregularity Time Series Analysis and Trend Forecasting

    Directory of Open Access Journals (Sweden)

    Jia Chaolong

    2012-01-01

    Full Text Available The combination of linear and nonlinear methods is widely used in the prediction of time series data. This paper analyzes track irregularity time series data by using gray incidence degree models and methods of data transformation, trying to find the connotative relationship between the time series data. In this paper, GM (1,1 is based on first-order, single variable linear differential equations; after an adaptive improvement and error correction, it is used to predict the long-term changing trend of track irregularity at a fixed measuring point; the stochastic linear AR, Kalman filtering model, and artificial neural network model are applied to predict the short-term changing trend of track irregularity at unit section. Both long-term and short-term changes prove that the model is effective and can achieve the expected accuracy.

  18. Exploring Manycore Multinode Systems for Irregular Applications with FPGA Prototyping

    Energy Technology Data Exchange (ETDEWEB)

    Ceriani, Marco; Palermo, Gianluca; Secchi, Simone; Tumeo, Antonino; Villa, Oreste

    2013-04-29

    We present a prototype of a multi-core architecture implemented on FPGA, designed to enable efficient execution of irregular applications on distributed shared memory machines, while maintaining high performance on regular workloads. The architecture is composed of off-the-shelf soft-core cores, local interconnection and memory interface, integrated with custom components that optimize it for irregular applications. It relies on three key elements: a global address space, multithreading, and fine-grained synchronization. Global addresses are scrambled to reduce the formation of network hot-spots, while the latency of the transactions is covered by integrating an hardware scheduler within the custom load/store buffers to take advantage from the availability of multiple executions threads, increasing the efficiency in a transparent way to the application. We evaluated a dual node system irregular kernels showing scalability in the number of cores and threads.

  19. Rhythm production at school entry as a predictor of poor reading and spelling at the end of first grade.

    Science.gov (United States)

    Lundetræ, Kjersti; Thomson, Jenny M

    2018-01-01

    Rhythm plays an organisational role in the prosody and phonology of language, and children with literacy difficulties have been found to demonstrate poor rhythmic perception. This study explored whether students' performance on a simple rhythm task at school entry could serve as a predictor of whether they would face difficulties in word reading and spelling at the end of grade 1. The participants were 479 Norwegian 6-year-old first graders randomized as controls in the longitudinal RCT on track (n = 1171). Rhythmic timing and pre-reading skills were tested individually at school entry on a digital tablet. On the rhythm task, the students were told to tap a drum appearing on the screen to two different rhythms (2 Hz paced and 1.5 Hz paced). Children's responses were recorded as they tapped on the screen with their index finger. Significant group differences were found in rhythm tapping ability measured at school entry, when groups were defined upon whether children went on to score above or below the 20th percentile reading and spelling thresholds in national assessment tests at the end of grade one. Inclusion of the school-entry rhythmic tapping measure into a model of classification accuracy for above or below threshold reading and spelling improved accuracy of classification by 6.2 and 9.2% respectively.

  20. Influence of diuretic therapy on the features of heart rhythm variability changes in chronic heart failure patients

    Directory of Open Access Journals (Sweden)

    K R Alyeva

    2018-02-01

    Full Text Available Aim. To study comparative influence of furosemide and torasemide on heart rhythm variability in patients with chronic heart failure of ischemic origin. Methods. The study included 48 patients (29 males and 19 females with ischemic heart disease complicated by chronic heart failure, NYHA functional classes II-IV. All patients were randomized into two groups: group 1 (25 patients received furosemide as diuretic therapy, and group 2 (23 patients received torasemide. All patient underwent clinical examination including assessment of complaints and physical examination, laboratory and instrumental tests (electrocardiography, echocardiography, 6-minute walk test, 24 Hour Holter ECG monitoring before and 30 days after starting diuretic therapy. Results. Against the background of one-month diuretic therapy, positive dynamics of clinical parameters was registered in both main groups of patients receiving both furosemide and torasemide. In furosemide group deterioration of heart rhythm variability was observed. Torasemide treatment resulted in considerable improvement of vegetative regulation of heart activity. Conclusion. Diuretic therapy with furosemide is characterized by changes of time and spectral parameters of vegetative regulation of heart rhythm towards strengthening of sympathetic and attenuation of parasympathetic influence; diuretic therapy with torasemide resulted in considerable improvement of heart rhythm variability parameters, attenuation of sympathetic and strengthening of parasympathetic influence on heart rhythm that provides additional cardioprotection in the treatment of patients with chronic heart failure of ischemic origin.

  1. Criticality predicts maximum irregularity in recurrent networks of excitatory nodes.

    Directory of Open Access Journals (Sweden)

    Yahya Karimipanah

    Full Text Available A rigorous understanding of brain dynamics and function requires a conceptual bridge between multiple levels of organization, including neural spiking and network-level population activity. Mounting evidence suggests that neural networks of cerebral cortex operate at a critical regime, which is defined as a transition point between two phases of short lasting and chaotic activity. However, despite the fact that criticality brings about certain functional advantages for information processing, its supporting evidence is still far from conclusive, as it has been mostly based on power law scaling of size and durations of cascades of activity. Moreover, to what degree such hypothesis could explain some fundamental features of neural activity is still largely unknown. One of the most prevalent features of cortical activity in vivo is known to be spike irregularity of spike trains, which is measured in terms of the coefficient of variation (CV larger than one. Here, using a minimal computational model of excitatory nodes, we show that irregular spiking (CV > 1 naturally emerges in a recurrent network operating at criticality. More importantly, we show that even at the presence of other sources of spike irregularity, being at criticality maximizes the mean coefficient of variation of neurons, thereby maximizing their spike irregularity. Furthermore, we also show that such a maximized irregularity results in maximum correlation between neuronal firing rates and their corresponding spike irregularity (measured in terms of CV. On the one hand, using a model in the universality class of directed percolation, we propose new hallmarks of criticality at single-unit level, which could be applicable to any network of excitable nodes. On the other hand, given the controversy of the neural criticality hypothesis, we discuss the limitation of this approach to neural systems and to what degree they support the criticality hypothesis in real neural networks. Finally

  2. Propagation and scattering of electromagnetic waves by the ionospheric irregularities

    International Nuclear Information System (INIS)

    Ho, A.Y.; Kuo, S.P.; Lee, M.C.

    1993-01-01

    The problem of wave propagation and scattering in the ionosphere is particularly important in the areas of communications, remote-sensing and detection. The ionosphere is often perturbed with coherently structured (quasiperiodic) density irregularities. Experimental observations suggest that these irregularities could give rise to significant ionospheric effect on wave propagation such as causing spread-F of the probing HF sounding signals and scintillation of beacon satellite signals. It was show by the latter that scintillation index S 4 ∼ 0.5 and may be as high as 0.8. In this work a quasi-particle theory is developed to study the scintillation phenomenon. A Wigner distribution function for the wave intensity in the (k,r) space is introduced and its governing equation is derived with an effective collision term giving rise to the attenuation and scattering of the wave. This kinetic equation leads to a hierarchy of moment equations in r space. This systems of equations is then truncated to the second moment which is equivalent to assuming a cold quasi-particle distribution In this analysis, the irregularities are modeled as a two dimensional density modulation on an uniform background plasma. The analysis shows that this two dimensional density grating, effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then contributes to the scintillation of the beacon satellite signals. Using the proper plasma parameters and equatorial measured data of irregularities, it is shown that the scintillation index defined by S4=( 2 >- 2 )/ 2 where stands for spatial average over an irregularity wavelength is in the range of the experimentally detected values

  3. Irregular Shaped Building Design Optimization with Building Information Modelling

    Directory of Open Access Journals (Sweden)

    Lee Xia Sheng

    2016-01-01

    Full Text Available This research is to recognise the function of Building Information Modelling (BIM in design optimization for irregular shaped buildings. The study focuses on a conceptual irregular shaped “twisted” building design similar to some existing sculpture-like architectures. Form and function are the two most important aspects of new buildings, which are becoming more sophisticated as parts of equally sophisticated “systems” that we are living in. Nowadays, it is common to have irregular shaped or sculpture-like buildings which are very different when compared to regular buildings. Construction industry stakeholders are facing stiff challenges in many aspects such as buildability, cost effectiveness, delivery time and facility management when dealing with irregular shaped building projects. Building Information Modelling (BIM is being utilized to enable architects, engineers and constructors to gain improved visualization for irregular shaped buildings; this has a purpose of identifying critical issues before initiating physical construction work. In this study, three variations of design options differing in rotating angle: 30 degrees, 60 degrees and 90 degrees are created to conduct quantifiable comparisons. Discussions are focused on three major aspects including structural planning, usable building space, and structural constructability. This research concludes that Building Information Modelling is instrumental in facilitating design optimization for irregular shaped building. In the process of comparing different design variations, instead of just giving “yes or no” type of response, stakeholders can now easily visualize, evaluate and decide to achieve the right balance based on their own criteria. Therefore, construction project stakeholders are empowered with superior evaluation and decision making capability.

  4. Low frequency sound reproduction in irregular rooms using CABS (Control Acoustic Bass System)

    DEFF Research Database (Denmark)

    Celestinos, Adrian; Nielsen, Sofus Birkedal

    2011-01-01

    of an irregular room model using the FDTD (Finite Difference Time Domain) method has been presented. CABS has been simulated in the irregular room model. Measurements of CABS in a real irregular room have been performed. The performance of CABS was affected by the irregular shape of the room due to the corner...

  5. A Reliable Method for Rhythm Analysis during Cardiopulmonary Resuscitation

    Directory of Open Access Journals (Sweden)

    U. Ayala

    2014-01-01

    Full Text Available Interruptions in cardiopulmonary resuscitation (CPR compromise defibrillation success. However, CPR must be interrupted to analyze the rhythm because although current methods for rhythm analysis during CPR have high sensitivity for shockable rhythms, the specificity for nonshockable rhythms is still too low. This paper introduces a new approach to rhythm analysis during CPR that combines two strategies: a state-of-the-art CPR artifact suppression filter and a shock advice algorithm (SAA designed to optimally classify the filtered signal. Emphasis is on designing an algorithm with high specificity. The SAA includes a detector for low electrical activity rhythms to increase the specificity, and a shock/no-shock decision algorithm based on a support vector machine classifier using slope and frequency features. For this study, 1185 shockable and 6482 nonshockable 9-s segments corrupted by CPR artifacts were obtained from 247 patients suffering out-of-hospital cardiac arrest. The segments were split into a training and a test set. For the test set, the sensitivity and specificity for rhythm analysis during CPR were 91.0% and 96.6%, respectively. This new approach shows an important increase in specificity without compromising the sensitivity when compared to previous studies.

  6. Neural responses to complex auditory rhythms: the role of attending

    Directory of Open Access Journals (Sweden)

    Heather L Chapin

    2010-12-01

    Full Text Available The aim of this study was to explore the role of attention in pulse and meter perception using complex rhythms. We used a selective attention paradigm in which participants attended to either a complex auditory rhythm or a visually presented word list. Performance on a reproduction task was used to gauge whether participants were attending to the appropriate stimulus. We hypothesized that attention to complex rhythms – which contain no energy at the pulse frequency – would lead to activations in motor areas involved in pulse perception. Moreover, because multiple repetitions of a complex rhythm are needed to perceive a pulse, activations in pulse related areas would be seen only after sufficient time had elapsed for pulse perception to develop. Selective attention was also expected to modulate activity in sensory areas specific to the modality. We found that selective attention to rhythms led to increased BOLD responses in basal ganglia, and basal ganglia activity was observed only after the rhythms had cycled enough times for a stable pulse percept to develop. These observations suggest that attention is needed to recruit motor activations associated with the perception of pulse in complex rhythms. Moreover, attention to the auditory stimulus enhanced activity in an attentional sensory network including primary auditory, insula, anterior cingulate, and prefrontal cortex, and suppressed activity in sensory areas associated with attending to the visual stimulus.

  7. Menstrual irregularity and poly cystic ovarian syndrome among adolescent girls--a 2 year follow-up study.

    Science.gov (United States)

    Nair, M K C; Pappachan, Princly; Balakrishnan, Sheila; Leena, M L; George, Babu; Russell, Paul S

    2012-01-01

    To study the clinical outcome after a gap of 2 years, among adolescent girls with confirmed menstrual irregularity and with or without ultrasound diagnosed polycystic ovaries. 136 adolescent girls from a cohort of 301 girls between 15 and 17 years of age with confirmed menstrual irregularity, with or without ultrasound diagnosed polycystic ovaries, were assessed in detail after a gap of 2 years. Present menstrual history and symptoms as well as signs of polycystic ovary syndrome (PCOS) were recorded, apart from ultrasound scanning of abdomen. PCOS was diagnosed using Rotterdam's consensus criteria and a comparative analysis was done among cases with and without PCOS. In the phase-II study done after a gap of 2 years, there was a statistically significant lower percentage of irregularities in menses, acne and enlarged thyroid, but a statistically significant increase in hirsuitism as compared to Phase-I study. Of the 136 cases reported, 36.0% cases were found to have PCOS and 63.9% cases were normal. Comparison of the two groups showed a statistically significant higher percentage difference in prevalence of irregular menses (59.9%), hirsuitism (56.3%), acne (17.8%), obesity (17.3%), polycystic ovaries on ultrasound (47.8%) and clinical hyperandrogenism (56.1%) among those with PCOS as against those without PCOS. The results of this study support screening for menstrual irregularity, obesity and signs of clinical hyperandrogenism for early diagnosis of PCOS in an effort to improve the reproductive health of adolescent girls.

  8. Characterizing spontaneous irregular behavior in coupled map lattices

    International Nuclear Information System (INIS)

    Dobyns, York; Atmanspacher, Harald

    2005-01-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties

  9. Characterizing spontaneous irregular behavior in coupled map lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dobyns, York [PEAR, Princeton University Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene Wilhelmstrasse 3a, Freiburg 79098 (Germany)]. E-mail: haa@igpp.de

    2005-04-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties.

  10. [Artificial cycle therapy of acupuncture and moxibustion for irregular menstruation].

    Science.gov (United States)

    Wu, Jie; Yang, Lijie; Chen, Yajie; Li, Qing; Chen, Lin

    2015-03-01

    Through the discussion on TCM physiological characters of females in follicular, ovulatory, luteal and menstrual phases and treatment principles, the clinical application of artificial cycle therapy of acupuncture and moxibustion was introduced for irregular menstruation and the typical cases were attached. It is suggested that the menstrual cycle follows the growth-consumption rule of yin, yang, qi and blood. The corresponding treatment principles should be applied in accordance with the change rule of menstrual cycle. Hence, it is worth to adopt the artificial cycle therapy of acupuncture and moxibustion for irregular menstruation in clinical application.

  11. Uniform irradiation of irregularly shaped cavities for photodynamic therapy.

    Science.gov (United States)

    Rem, A I; van Gemert, M J; van der Meulen, F W; Gijsbers, G H; Beek, J F

    1997-03-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a 'bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the 'radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution.

  12. The role of the daily feeding rhythm in the regulation of the day/night rhythm in triglyceride secretion in rats.

    Science.gov (United States)

    Su, Yan; Foppen, Ewout; Mansur Machado, Frederico Sander; Fliers, Eric; Kalsbeek, Andries

    2018-02-15

    Plasma triglyceride (TG) levels show a clear daily rhythm, however, thus far it is still unknown whether this rhythm results from a daily rhythm in TG production, TG uptake or both. Previous studies have shown that feeding activity affects plasma TG concentrations, but it is not clear how the daily rhythm in feeding activity affects plasma TG concentrations. In the present study, we measured plasma TG concentrations and TG secretion rates in rats at 6 Zeitgeber times to investigate whether plasma TG concentrations and TG secretion show a daily rhythm. We found that plasma TG concentrations and TG secretion show a significant day/night rhythm. Next, we removed the daily rhythm in feeding behavior by introducing a 6-meals-a-day (6M) feeding schedule to investigate whether the daily rhythm in feeding behavior is necessary to maintain the daily rhythm in TG secretion. We found that the day/night rhythm in TG secretion was abolished under 6M feeding conditions. Hepatic apolipoprotein B (ApoB) and microsomal TG transfer protein (Mttp), which are both involved in TG secretion, also lost their daily rhythmicity under 6M feeding conditions. Together, these results indicate that: (1) the daily rhythm in TG secretion contributes to the formation of a day/night rhythm in plasma TG levels and (2) a daily feeding rhythm is essential for maintaining the daily rhythm in TG secretion.

  13. Bleeding risk assessment and management in atrial fibrillation patients: a position document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis

    NARCIS (Netherlands)

    Lip, Gregory Y. H.; Andreotti, Felicita; Fauchier, Laurent; Huber, Kurt; Hylek, Elaine; Knight, Eve; Lane, Deirdre A.; Levi, Marcel; Marin, Francisco; Palareti, Gualtiero; Kirchhof, Paulus; Collet, Jean-Philippe; Rubboli, Andrea; Poli, Daniela; Camm, John

    2011-01-01

    Despite the clear net clinical benefit of oral anticoagulation (OAC) in atrial fibrillation (AF) patients at risk for stroke, major bleeding events (especially intra-cranial bleeds) may be devastating events when they do occur. The decision for OAC is often based on a careful assessment of both

  14. Targeting overall equipment efficiency for small medium enterprises with irregular production system

    Science.gov (United States)

    Prasetyawan, Y.; Suef, M.; Claudia, L.; Handayani, F. D.

    2018-04-01

    Overall Equipment Effectiveness (OEE) is widely used to measure the maturity of a production system. The company will be considered as World Class Manufacturing if it reaches more than 85% value, with near perfect value for availability, performance and quality factor. This assessment is usually taken on industries with regular production times named shift system. A typical 8 hours shift system is used in OEE measurement and performance monitoring. There are few Small to Medium Enterprise (SME) perform regular production times with shift systems, others using irregular production systems. The irregular production time in the SME production system is used because of demand fluctuations. This paper shows a quantitative analysis as a part of manufacturing system design to achieve a specific value of OEE for SME with irregular production systems, for individual businesses as well as collective business systems (some companies use the same production facilities for several processes). The results of experiments on several companies are presented, as a basis for determining the technical strategy of achieving OEE values.

  15. Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012.

    Science.gov (United States)

    Ko, Kyung Min; Han, Kyungdo; Chung, Youn Jee; Yoon, Kun Ho; Park, Yong Gyu; Lee, Seung Hwan

    2017-06-01

    Menstrual irregularity is an indicator of endocrine disorders and reproductive health status. It is associated with various diseases and medical conditions, including obesity and underweight. We aimed to assess the association between body weight changes and menstrual irregularity in Korean women. A total of 4,621 women 19 to 54 years of age who participated in the 2010 to 2012 Korea National Health and Nutrition Examination Survey were included in this study. Self-reported questionnaires were used to collect medical information assessing menstrual health status and body weight changes. Odds ratios (ORs) and 95% confidence interval (CI) were calculated to evaluate the association between body weight changes and menstrual irregularity. Significantly higher ORs (95% CI) were observed in the association between menstrual irregularity and both weight loss (OR, 1.74; 95% CI, 1.22 to 2.48) and weight gain (OR, 1.45; 95% CI, 1.13 to 1.86) after adjusting for age, body mass index, current smoking, heavy alcohol drinking, regular exercise, calorie intake, education, income, metabolic syndrome, age of menarche, parity, and stress perception. Of note, significant associations were only observed in subjects with obesity and abdominal obesity, but not in non-obese or non-abdominally obese subjects. U-shaped patterns were demonstrated in both obese and abdominally obese subjects, indicating that greater changes in body weight are associated with higher odds of menstrual irregularity. We found a U-shaped pattern of association between body weight changes and menstrual irregularity among obese women in the general Korean population. This result indicates that not only proper weight management but also changes in body weight may influence the regulation of the menstrual cycle. Copyright © 2017 Korean Endocrine Society

  16. Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012

    Directory of Open Access Journals (Sweden)

    Kyung Min Ko

    2017-06-01

    Full Text Available BackgroundMenstrual irregularity is an indicator of endocrine disorders and reproductive health status. It is associated with various diseases and medical conditions, including obesity and underweight. We aimed to assess the association between body weight changes and menstrual irregularity in Korean women.MethodsA total of 4,621 women 19 to 54 years of age who participated in the 2010 to 2012 Korea National Health and Nutrition Examination Survey were included in this study. Self-reported questionnaires were used to collect medical information assessing menstrual health status and body weight changes. Odds ratios (ORs and 95% confidence interval (CI were calculated to evaluate the association between body weight changes and menstrual irregularity.ResultsSignificantly higher ORs (95% CI were observed in the association between menstrual irregularity and both weight loss (OR, 1.74; 95% CI, 1.22 to 2.48 and weight gain (OR, 1.45; 95% CI, 1.13 to 1.86 after adjusting for age, body mass index, current smoking, heavy alcohol drinking, regular exercise, calorie intake, education, income, metabolic syndrome, age of menarche, parity, and stress perception. Of note, significant associations were only observed in subjects with obesity and abdominal obesity, but not in non-obese or non-abdominally obese subjects. U-shaped patterns were demonstrated in both obese and abdominally obese subjects, indicating that greater changes in body weight are associated with higher odds of menstrual irregularity.ConclusionWe found a U-shaped pattern of association between body weight changes and menstrual irregularity among obese women in the general Korean population. This result indicates that not only proper weight management but also changes in body weight may influence the regulation of the menstrual cycle.

  17. Sleep quality and circadian rhythm disruption in the intensive care unit

    DEFF Research Database (Denmark)

    Boyko, Yuliya; Jennum, Poul; Toft, Palle

    2017-01-01

    Sleep and circadian rhythm are reported to be severely abnormal in critically ill patients. Disturbed sleep can lead to the development of delirium and, as a result, can be associated with prolonged stay in the intensive care unit (ICU) and increased mortality. The standard criterion method...... aiming to improve sleep quality and circadian rhythm in the ICU. The results of these studies were inconclusive due to using the sleep assessment methods other than PSG or the absence of a reliable sleep scoring tool for the analysis of the PSG findings in this patient population. Development of a valid......, medication, as well as the critical illness itself have been reported as important sleep disturbing factors. Secretion of sleep hormone, melatonin, expressing circadian rhythmicity was found abolished or phase delayed in critically ill patients. Various interventions have been tested in several studies...

  18. A novel algorithm for detecting human circadian rhythms using a thoracic temperature sensor

    Directory of Open Access Journals (Sweden)

    Aly Chkeir

    2017-07-01

    Full Text Available Circadian rhythms undergo high perturbations due to cancer progression and worsening of metabolic diseases. This paper proposes an original method for detecting such perturbations using a novel thoracic temperature sensor. Such an infrared sensor records the skin temperature every five minutes, although some data might be missing. In this pilot study, five control subjects were evaluated over four days of recordings. In order to overcome the problem of missing data, first four different interpolation methods were compared. Using interpolation helps covering the gaps and extending the recordings frequency, subsequently prolonging sensor battery life. Afterwards, a Cosinor model was proposed to characterize circadian rhythms, and extract relevant parameters, with their confidence limits. A divergence study is then performed to detect changes in these parameters. The results are promising, supporting the enlargement of the sample size and warranting further assessment in cancer patients.

  19. EEG Mu Rhythm and Imitation Impairments in Individuals with Autism Spectrum Disorder

    Science.gov (United States)

    Bernier, R.; Dawson, G.; Webb, S.; Murias, M.

    2009-01-01

    Imitation ability has consistently been shown to be impaired in individuals with autism. A dysfunctional execution/observation matching system has been proposed to account for this impairment. The EEG mu rhythm is believed to reflect an underlying execution/observation matching system. This study investigated evidence of differential mu rhythm attenuation during the observation, execution, and imitation of movements and examined its relation to behaviorally assessed imitation abilities. Fourteen high-functioning adults with autism spectrum disorder (ASD) and 15 IQ- and age-matched typical adults participated. On the behavioral imitation task, adults with ASD demonstrated significantly poorer performance compared to typical adults in all domains of imitation ability. On the EEG task, both groups demonstrated significant attenuation of the mu rhythm when executing an action. However, when observing movement, the individuals with ASD showed significantly reduced attenuation of the mu wave. Behaviorally assessed imitation skills were correlated with degree of mu wave attenuation during observation of movement. These findings suggest that there is execution/observation matching system dysfunction in individuals with autism and that this matching system is related to degree of impairment in imitation abilities. PMID:17451856

  20. Runtime buffer management to improve the performance in irregular ...

    Indian Academy of Sciences (India)

    S¯adhan¯a Vol. 40, Part 4, June 2015, pp. 1117–1137. c Indian Academy of Sciences. Runtime buffer management to improve the performance in irregular Network-on-Chip architecture. UMAMAHESWARI S1,∗, MEGANATHAN D2 and. RAJA PAUL PERINBAM J3. 1Department of Information Technology, Anna University, ...

  1. Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Andersen, Nis Korsgaard; Søgaard, Emil

    2014-01-01

    -off angles is found to be caused by a decrease of the receding contact angle, which in turn is caused by an increase of the triple phase contact line of the drops for those more irregular surfaces. To understand the observation, we propose to treat the microdrops as rigid bodies and apply a torque balance...

  2. The regularized monotonicity method: detecting irregular indefinite inclusions

    DEFF Research Database (Denmark)

    Garde, Henrik; Staboulis, Stratos

    2018-01-01

    inclusions, where the conductivity distribution has both more and less conductive parts relative to the background conductivity; one such method is the monotonicity method of Harrach, Seo, and Ullrich. We formulate the method for irregular indefinite inclusions, meaning that we make no regularity assumptions...

  3. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

  4. Interagency Cooperation for Irregular Warfare at the Combatant Command

    Science.gov (United States)

    2009-01-01

    enemy’s command capability.16 Salamoni argued that the term “irregular warfare” belies an ethnocentric perspective of conflict that will limit military...duty military staffing to form the nucleus of the organization, which would receive augmentation from additional assigned reservists and interagency

  5. Convection-diffusion lattice Boltzmann scheme for irregular lattices

    NARCIS (Netherlands)

    Sman, van der R.G.M.; Ernst, M.H.

    2000-01-01

    In this paper, a lattice Boltzmann (LB) scheme for convection diffusion on irregular lattices is presented, which is free of any interpolation or coarse graining step. The scheme is derived using the axioma that the velocity moments of the equilibrium distribution equal those of the

  6. Swiveling Lathe Jaw Concept for Holding Irregular Pieces

    Science.gov (United States)

    David, J.

    1966-01-01

    Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

  7. Why type 2 supernovae do not explode in irregular galaxies

    International Nuclear Information System (INIS)

    Shklovskij, I.S.

    1984-01-01

    The conclusion is drawn that reason for an absence of type 2 supernovae explosions in irregular galaxies is their peculiar chemical composition. The observed lack of stellar wind from massive hot giants is due to relatively low heavy element abundance. For this reason evolving massive stars do not form an extended dense envelopes that is a necessary condition for the type 2 supernova phenomenon

  8. First stellar abundances in the dwarf irregular galaxy Sextans A

    NARCIS (Netherlands)

    Kaufer, A; Venn, KA; Tolstoy, E; Pinte, C; Kudritzki, RP

    We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A (= DDO 75) from high-resolution spectra obtained with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the Kueyen telescope (UT2) of the ESO Very Large Telescope (VLT). Detailed

  9. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    Yan Hui Geng

    2018-03-14

    Mar 14, 2018 ... Abstract. A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the ...

  10. On the Total Edge Irregularity Strength of Generalized Butterfly Graph

    Science.gov (United States)

    Dwi Wahyuna, Hafidhyah; Indriati, Diari

    2018-04-01

    Let G(V, E) be a connected, simple, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ: V(G) ∪ E(G) → {1, 2, …, k} of a graph G is a total k-labeling such that the weights calculated for all edges are distinct. The weight of an edge uv in G, denoted by wt(uv), is defined as the sum of the label of u, the label of v, and the label of uv. The total edge irregularity strength of G, denoted by tes(G), is the minimum value of the largest label k over all such edge irregular total k-labelings. A generalized butterfly graph, BFn , obtained by inserting vertices to every wing with assumption that sum of inserting vertices to every wing are same then it has 2n + 1 vertices and 4n ‑ 2 edges. In this paper, we investigate the total edge irregularity strength of generalized butterfly graph, BFn , for n > 2. The result is tes(B{F}n)=\\lceil \\frac{4n}{3}\\rceil .

  11. On a new process for cusp irregularity production

    Directory of Open Access Journals (Sweden)

    H. C. Carlson

    2008-09-01

    Full Text Available Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability. The former mechanism was accepted as accounting for plasma structuring in polar cap patches, the latter for plasma structuring in polar cap sun aligned arcs. Recent work has established the need to replace this view of the past two decades with a new patch plasma structuring process (not a new mechanism, whereby shear-driven instabilities first rapidly structure the entering plasma, after which gradient drift instabilities build on these large "seed" irregularities. Correct modeling of cusp and early polar cap patch structuring will not be accomplished without allowing for this compound process. This compound process explains several previously unexplained characteristics of cusp and early polar cap patch irregularities. Here we introduce additional data, coincident in time and space, to extend that work to smaller irregularity scale sizes and relate it to the structured cusp current system.

  12. Irregular ionization and scintillation of the ionosphere in equator region

    International Nuclear Information System (INIS)

    Shinno, Kenji

    1974-01-01

    The latest studies on the scintillation in satellite communication and its related irregularities of ionosphere are reviewed. They were made clear by means of spread-F, the direct measurement with scientific satellites, VHF radar observation, and radio wave propagation in equator region. The fundamental occurrence mechanism may be instability of plasma caused by the interaction of movement of neutral atmosphere and magnetic field. Comparison of the main characteristics of scintillation, namely the dependence on region, solar activity, season, local time, geomagnetic activity, movement in ionosphere, scattering source, frequency and transmission mode, was made and the correlation among spread-F, TEP and scintillation was summarized. The latest principal studies were the observations made by Intelsat and by ATS. Scintillation of Syncom-3 and Intelsat-II-F2 and spread-F by ionosphere observation were compared by Huang. It is reasonable to consider that the occurrence of scintillation is caused by the irregularities in ionosphere which are particular in equator region, because of the similar characteristics of spread-F and VHF propagation in the equator region. These three phenomena may occur in relation to the irregularities of ionosphere. Interpretation of spread-F and the abnormal propagation wave across the equator are given. The study using VHF radar and the movement of irregular ionization by the direct observation with artificial satellites are reviewd. (Iwakiri, K.)

  13. Third-order theory for multi-directional irregular waves

    DEFF Research Database (Denmark)

    Madsen, Per A.; Fuhrman, David R.

    2012-01-01

    A new third-order solution for multi-directional irregular water waves in finite water depth is presented. The solution includes explicit expressions for the surface elevation, the amplitude dispersion and the vertical variation of the velocity potential. Expressions for the velocity potential at...

  14. Irregular menses: an independent risk factor for gestational diabetes mellitus.

    Science.gov (United States)

    Haver, Mary Claire; Locksmith, Gregory J; Emmet, Emily

    2003-05-01

    Our purpose was to determine whether a history of irregular menses predicts gestational diabetes mellitus independently of traditional risk factors. We analyzed demographic characteristics, body mass index, and menstrual history of 85 pregnant women with gestational diabetes mellitus and compared them with 85 systematically selected control subjects who were matched for age, race, and delivery year. Subjects with pregestational diabetes mellitus, previous gestational diabetes mellitus, family history of diabetes mellitus, weight >200 pounds, previous macrosomic infants, or previous stillbirth were excluded. Demographic characteristics between case and control groups were similar. Mean body mass index was higher among cases (26.5 kg/m(2)) versus control subjects (24.5 kg/m(2), P =.004). Irregular cycles were more prevalent in the cases (24% vs 7%, P =.006). With the use of body mass index as a stratification factor, menstrual irregularity maintained a strong association with gestational diabetes mellitus (P =.014). A history of irregular menstrual cycles was a significant independent predictor of gestational diabetes mellitus. If selective screening is implemented for gestational diabetes mellitus, such history should be considered in the decision of whom to test.

  15. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the physical space are ...

  16. Characteristics of low latitude ionospheric E-region irregularities ...

    Indian Academy of Sciences (India)

    154°E, dip angle = 37.3°, sub-ionospheric dip = 34°) have been analyzed to study the behaviour of ionospheric E-region irregularities during the active solar and magnetic periods. The autocorrelation functions, power spectral densities, signal de-correlation times are computed to study the temporal features of ionospheric ...

  17. Melatonin in sleepless children : everything has a rhythm?

    NARCIS (Netherlands)

    van Geijlswijk, I.M.

    2011-01-01

    Every living organism has an biological clock regulating endogenous melatonin production, synchronized by exogenous impulses like daylight, temperature and feeding. Inappropriately applied bright light disturbs this melatonin rhythm. Some large swine producers apply artificial light three times a

  18. Introduction: circadian rhythm and its disruption: impact on reproductive function.

    Science.gov (United States)

    Casper, Robert F; Gladanac, Bojana

    2014-08-01

    Almost all forms of life have predictable daily or circadian rhythms in molecular, endocrine, and behavioral functions. In mammals, a central pacemaker located in the suprachiasmatic nuclei coordinates the timing of these rhythms. Daily light exposure that affects the retina of the eye directly influences this area, which is required to align endogenous processes to the appropriate time of day. The present "Views and Reviews" articles discuss the influence of circadian rhythms, especially nightly secretion of melatonin, on reproductive function and parturition. In addition, an examination is made of problems that arise from recurrent circadian rhythm disruption associated with changes in light exposure patterns common to modern day society. Finally, a possible solution to prevent disruptions in circadian phase markers by filtering out short wavelengths from nocturnal light is reviewed. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Classical limit of irregular blocks and Mathieu functions

    International Nuclear Information System (INIS)

    Piątek, Marcin; Pietrykowski, Artur R.

    2016-01-01

    The Nekrasov-Shatashvili limit of the N = 2 SU(2) pure gauge (Ω-deformed) super Yang-Mills theory encodes the information about the spectrum of the Mathieu operator. On the other hand, the Mathieu equation emerges entirely within the frame of two-dimensional conformal field theory (2d CFT) as the classical limit of the null vector decoupling equation for some degenerate irregular block. Therefore, it seems to be possible to investigate the spectrum of the Mathieu operator employing the techniques of 2d CFT. To exploit this strategy, a full correspondence between the Mathieu equation and its realization within 2d CFT has to be established. In our previous paper http://dx.doi.org/10.1007/JHEP12(2014)032, we have found that the expression of the Mathieu eigenvalue given in terms of the classical irregular block exactly coincides with the well known weak coupling expansion of this eigenvalue in the case in which the auxiliary parameter is the noninteger Floquet exponent. In the present work we verify that the formula for the corresponding eigenfunction obtained from the irregular block reproduces the so-called Mathieu exponent from which the noninteger order elliptic cosine and sine functions may be constructed. The derivation of the Mathieu equation within the formalism of 2d CFT is based on conjectures concerning the asymptotic behaviour of irregular blocks in the classical limit. A proof of these hypotheses is sketched. Finally, we speculate on how it could be possible to use the methods of 2d CFT in order to get from the irregular block the eigenvalues of the Mathieu operator in other regions of the coupling constant.

  20. Comparison of correlation analysis techniques for irregularly sampled time series

    Directory of Open Access Journals (Sweden)

    K. Rehfeld

    2011-06-01

    Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

    All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

    We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ18O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

  1. Gamification Quest: Rhythm. Music as a game mechanic

    OpenAIRE

    Granell Díaz, Marina

    2017-01-01

    Treball Final de Grau en Disseny i Desenvolupament de Videojocs. Codi: VJ1241. Curs acadèmic: 2016/2017 This document constitutes the Technical Report for the project Gamification Quest: Rhythm, music as a game mechanic for the Videogame Design and Development bachelor degree. The project consists on the design and implementation of rhythm game mechanics integrated in a gamification environment applied to education. The video game will be implemented on the game engine Unity (10), ...

  2. Using Rhythms of Relationships to Understand Email Archives

    National Research Council Canada - National Science Library

    Perer, Adam; Shneiderman, Ben; Oard, Douglas W

    2005-01-01

    ...: analyzing the temporal rhythms of social relationships. We provide methods for constructing meaningful rhythms from the email headers by identifying relationships and interpreting their attributes. With these visualization techniques, email archive explorers can uncover insights that may have been otherwise hidden in the archive. We apply our methods to an individual's fifteen-year email archive, which consists of about 45,000 messages and over 4,000 relationships.

  3. Human daily rhythms measured for one year.

    Science.gov (United States)

    Binkley, S; Tome, M B; Crawford, D; Mosher, K

    1990-08-01

    Four human subjects recorded their wake-up and to-sleep times for one year each. The data were plotted to display individual circadian rhythms and the data were analyzed statistically. First, individuals had characteristic patterns in which visible changes in the patterns were observed mainly when time zones were changed because of travel. Second, the months with the latest wake-up and latest to-sleep times concentrated around the winter solstice; the months with the earliest wake-up and earliest to-sleep times concentrated around the fall equinox. Third, new moon versus full moon days were not different. Fourth, one-hour changes between standard and daylight savings time in the USA were reflected by near one-hour changes in two subjects, but not in a third. Fifth, weekend delays in wake-up time (0.8-1.6 hours), weekend delays in to-sleep time (0.1-0.5 hours), and shorter weekend awake time (0.8-1.3 hours) were observed. Sixth, throughout the year, wake-up times were close to the time of sunrise, but to-sleep times were several hours past sunset.

  4. Music and speech prosody: a common rhythm.

    Science.gov (United States)

    Hausen, Maija; Torppa, Ritva; Salmela, Viljami R; Vainio, Martti; Särkämö, Teppo

    2013-01-01

    Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61) using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA) and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception, and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks) was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress).

  5. Music and speech prosody: A common rhythm

    Directory of Open Access Journals (Sweden)

    Maija eHausen

    2013-09-01

    Full Text Available Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61 using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress.

  6. Music and speech prosody: a common rhythm

    Science.gov (United States)

    Hausen, Maija; Torppa, Ritva; Salmela, Viljami R.; Vainio, Martti; Särkämö, Teppo

    2013-01-01

    Disorders of music and speech perception, known as amusia and aphasia, have traditionally been regarded as dissociated deficits based on studies of brain damaged patients. This has been taken as evidence that music and speech are perceived by largely separate and independent networks in the brain. However, recent studies of congenital amusia have broadened this view by showing that the deficit is associated with problems in perceiving speech prosody, especially intonation and emotional prosody. In the present study the association between the perception of music and speech prosody was investigated with healthy Finnish adults (n = 61) using an on-line music perception test including the Scale subtest of Montreal Battery of Evaluation of Amusia (MBEA) and Off-Beat and Out-of-key tasks as well as a prosodic verbal task that measures the perception of word stress. Regression analyses showed that there was a clear association between prosody perception and music perception, especially in the domain of rhythm perception. This association was evident after controlling for music education, age, pitch perception, visuospatial perception, and working memory. Pitch perception was significantly associated with music perception but not with prosody perception. The association between music perception and visuospatial perception (measured using analogous tasks) was less clear. Overall, the pattern of results indicates that there is a robust link between music and speech perception and that this link can be mediated by rhythmic cues (time and stress). PMID:24032022

  7. Circadian rhythm and sleep influences on digestive physiology and disorders

    Directory of Open Access Journals (Sweden)

    Vaughn BV

    2014-09-01

    Full Text Available Bradley V Vaughn, Sean Rotolo, Heidi L Roth Division of Sleep Medicine, Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC, USA Abstract: Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their role in normal physiology and the link of their disruption to pathological conditions. Recent work has demonstrated that sleep and circadian factors influence appetite, nutrient absorption, and metabolism. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues, irritable bowel disease, and gastrointestinal cancer. As our knowledge of the link between circadian timing and gastrointestinal physiology grows, so do our opportunities to provide promising diagnostic and therapeutic approaches for gastrointestinal disorders. Keywords: digestion, digestive diseases, gastrointestinal reflux, sleep, circadian rhythm 

  8. Educating the sense of rhythm in primary education students

    Directory of Open Access Journals (Sweden)

    Silvia GRĂDINARU

    2017-03-01

    Full Text Available Background: Rhythm as a core element of complex coordination is the key to efficient moulding of motor skills specific to sports activities in curricula. Practicing physical exercise in a varied rhythm and tempo in primary school students moulds the skill of achieving correct movement basics (direction, span, coordination, and expressivity. The use of music in sports classes improves kinetics and vestibular sensitivity. The sense of rhythm and tempo are imperative criteria in vocational schools. Purpose: This paper aims to describe a pattern of means selected to develop the sense of rhythm and to allow movements in different sports branches with increased efficiency. Methods: The test battery was applied on a sample of 15 students from the 4th grade of the “Ion Vidu” National Arts College in Timisoara, Romania, aged 9-10 years, over an entire school year, using different rhythms and tempos during sports classes, which were later used in gymnastics, athletic events, and basketball. Results: Data recorded after the application tests, processed and interpreted confirms the proposed assumption and validates the motor contents used. Conclusions: Sense of rhythm is a component of coordinative capacity that is required to be educated from an early age. Rhythmic movements are easier to automate saving energy and motivating students to an active and conscious participation.

  9. Implications of Circadian Rhythm in Dopamine and Mood Regulation.

    Science.gov (United States)

    Kim, Jeongah; Jang, Sangwon; Choe, Han Kyoung; Chung, Sooyoung; Son, Gi Hoon; Kim, Kyungjin

    2017-07-31

    Mammalian physiology and behavior are regulated by an internal time-keeping system, referred to as circadian rhythm. The circadian timing system has a hierarchical organization composed of the master clock in the suprachiasmatic nucleus (SCN) and local clocks in extra-SCN brain regions and peripheral organs. The circadian clock molecular mechanism involves a network of transcription-translation feedback loops. In addition to the clinical association between circadian rhythm disruption and mood disorders, recent studies have suggested a molecular link between mood regulation and circadian rhythm. Specifically, genetic deletion of the circadian nuclear receptor Rev-erbα induces mania-like behavior caused by increased midbrain dopaminergic (DAergic) tone at dusk. The association between circadian rhythm and emotion-related behaviors can be applied to pathological conditions, including neurodegenerative diseases. In Parkinson's disease (PD), DAergic neurons in the substantia nigra pars compacta progressively degenerate leading to motor dysfunction. Patients with PD also exhibit non-motor symptoms, including sleep disorder and neuropsychiatric disorders. Thus, it is important to understand the mechanisms that link the molecular circadian clock and brain machinery in the regulation of emotional behaviors and related midbrain DAergic neuronal circuits in healthy and pathological states. This review summarizes the current literature regarding the association between circadian rhythm and mood regulation from a chronobiological perspective, and may provide insight into therapeutic approaches to target psychiatric symptoms in neurodegenerative diseases involving circadian rhythm dysfunction.

  10. Dynamical Analysis of bantam-Regulated Drosophila Circadian Rhythm Model

    Science.gov (United States)

    Li, Ying; Liu, Zengrong

    MicroRNAs (miRNAs) interact with 3‧untranslated region (UTR) elements of target genes to regulate mRNA stability or translation, and play a crucial role in regulating many different biological processes. bantam, a conserved miRNA, is involved in several functions, such as regulating Drosophila growth and circadian rhythm. Recently, it has been discovered that bantam plays a crucial role in the core circadian pacemaker. In this paper, based on experimental observations, a detailed dynamical model of bantam-regulated circadian clock system is developed to show the post-transcriptional behaviors in the modulation of Drosophila circadian rhythm, in which the regulation of bantam is incorporated into a classical model. The dynamical behaviors of the model are consistent with the experimental observations, which shows that bantam is an important regulator of Drosophila circadian rhythm. The sensitivity analysis of parameters demonstrates that with the regulation of bantam the system is more sensitive to perturbations, indicating that bantam regulation makes it easier for the organism to modulate its period against the environmental perturbations. The effectiveness in rescuing locomotor activity rhythms of mutated flies shows that bantam is necessary for strong and sustained rhythms. In addition, the biological mechanisms of bantam regulation are analyzed, which may help us more clearly understand Drosophila circadian rhythm regulated by other miRNAs.

  11. [Melatonin, synthetic analogs, and the sleep/wake rhythm].

    Science.gov (United States)

    Escames, G; Acuña-Castroviejo, D

    Melatonin, a widespread hormone in the animal kingdom, is produced by several organs and tissues besides the pineal gland. Whilst extrapineal melatonin behaves as a cytoprotective molecule, the pineal produces the hormone in a rhythmic manner. The discovery of melatonin in 1958, and the characterization of its synthesis somewhat later, let to the description of its photoperiodic regulation and its relationship with the biological rhythms such as the sleep/wake rhythm. The suprachiasmatic nuclei are the anatomical seat of the biological clock, represented by the clock genes, which code for the period and frequency of the rhythms. The photoperiod synchronizes the activity of the auprachiasmatic biological clock, which in turn induces the melatonin's rhythm. The rhythm of melatonin, peaking at 2-3 am, acts as an endogenous synchronizer that translates the environmental photoperiodic signal in chemical information for the cells. The sleep/wake cycle is a typical biological rhythm synchronized by melatonin, and the sleep/wake cycle alterations of chronobiological origin, are very sensitive to melatonin treatment. Taking advantage of the chronobiotic and antidepressive properties of melatonin, a series of synthetic analogs of this hormone, with high interest in insomnia, are now available. Melatonin is a highly effective chronobiotic in the treatment of chronobiological alterations of the sleep/wake cycle. From a pharmacokinetic point of view, the synthetic drugs derived from melatonin are interesting tools in the therapy of these alterations.

  12. Entity’s Irregular Demand Scheduling of the Wholesale Electricity Market based on the Forecast of Hourly Price Ratios

    Directory of Open Access Journals (Sweden)

    O. V. Russkov

    2015-01-01

    Full Text Available The article considers a hot issue to forecast electric power demand amounts and prices for the entities of wholesale electricity market (WEM, which are in capacity of a large user with production technology requirements prevailing over hourly energy planning ones. An electric power demand of such entities is on irregular schedule. The article analyses mathematical models, currently applied to forecast demand amounts and prices. It describes limits of time-series models and fundamental ones in case of hourly forecasting an irregular demand schedule of the electricity market entity. The features of electricity trading at WEM are carefully analysed. Factors that influence on irregularity of demand schedule of the metallurgical plant are shown. The article proposes method for the qualitative forecast of market price ratios as a tool to reduce a dependence on the accuracy of forecasting an irregular schedule of demand. It describes the differences between the offered method and the similar ones considered in research studies and scholarly works. The correlation between price ratios and relaxation in the requirements for the forecast accuracy of the electric power consumption is analysed. The efficiency function of forecast method is derived. The article puts an increased focus on description of the mathematical model based on the method of qualitative forecast. It shows main model parameters and restrictions the electricity market imposes on them. The model prototype is described as a programme module. Methods to assess an effectiveness of the proposed forecast model are examined. The positive test results of the model using JSC «Volzhsky Pipe Plant» data are given. A conclusion is drawn concerning the possibility to decrease dependence on the forecast accuracy of irregular schedule of entity’s demand at WEM. The effective trading tool has been found for the entities of irregular demand schedule at WEM. The tool application allows minimizing cost

  13. Frailty syndrome in patients with heart rhythm disorders.

    Science.gov (United States)

    Mlynarska, Agnieszka; Mlynarski, Rafal; Golba, Krzysztof S

    2017-09-01

    To assess the prevalence of frailty syndrome in patients with heart rhythm disorders that qualified for pacemaker implantation. The study included 171 patients (83 women, aged 73.9 ± 6.7 years) who qualified for pacemaker implantation as a result of sinus node dysfunction (81 patients) or atrio-ventricular blocks (AVB; 90 patients). A total of 60 patients (25 women, aged 72.40 ± 7.09 years) without heart rhythm disorders were included in the control group. Frailty syndrome was diagnosed using the Canadian Study of Health and Aging Clinical Frailty Scale test. Frailty syndrome was diagnosed in 25.15% of the patients, and pre-frailty in 36.84% of the patients. Frailty syndrome was diagnosed in 10% of the control group, and the average value of frailty was 3.35 ± 0.92. Frailty occurred significantly more often among patients with AVB (33.34%) compared with patients who were diagnosed with sinus node dysfunction (16.05%); P = 0.0081. The average score of frailty for sinus node dysfunction was 3.71 ± 0.89, and for AVB it was 4.14 ± 0.93; P = 0.0152. In the case of AVB, the women had a statistically more intense level of frailty of 4.54 ± 0.90 as compared with the men 3.87 ± 0.85; P = 0.0294. In the multiple logistic analysis, the presence of any arrhythmia was strongly associated with frailty syndrome (OR 2.1286, 95% CI 1.4594 - 3.1049; P = 0.0001). Frailty syndrome was diagnosed in one-quarter of patients with cardiac arrhythmias, whereas a further 40% were at a higher risk of frailty syndrome, and its occurrence was significantly higher if compared with the control group. Frailty occurred significantly more often among patients with atrio-ventricular blocks, especially in women. The results of the present research showed that there is a statistical association between frailty and arrhythmias. Geriatr Gerontol Int 2017; 17: 1313-1318. © 2016 Japan Geriatrics Society.

  14. Speech rhythm alterations in Spanish-speaking individuals with Alzheimer's disease.

    Science.gov (United States)

    Martínez-Sánchez, Francisco; Meilán, Juan J G; Vera-Ferrandiz, Juan Antonio; Carro, Juan; Pujante-Valverde, Isabel M; Ivanova, Olga; Carcavilla, Nuria

    2017-07-01

    Rhythm is the speech property related to the temporal organization of sounds. Considerable evidence is now available for suggesting that dementia of Alzheimer's type is associated with impairments in speech rhythm. The aim of this study is to assess the use of an automatic computerized system for measuring speech rhythm characteristics in an oral reading task performed by 45 patients with Alzheimer's disease (AD) compared with those same characteristics among 82 healthy older adults without a diagnosis of dementia, and matched by age, sex and cultural background. Ranges of rhythmic-metric and clinical measurements were applied. The results show rhythmic differences between the groups, with higher variability of syllabic intervals in AD patients. Signal processing algorithms applied to oral reading recordings prove to be capable of differentiating between AD patients and older adults without dementia with an accuracy of 87% (specificity 81.7%, sensitivity 82.2%), based on the standard deviation of the duration of syllabic intervals. Experimental results show that the syllabic variability measurements extracted from the speech signal can be used to distinguish between older adults without a diagnosis of dementia and those with AD, and may be useful as a tool for the objective study and quantification of speech deficits in AD.

  15. Progestins alter photo-transduction cascade and circadian rhythm network in eyes of zebrafish (Danio rerio)

    Science.gov (United States)

    Zhao, Yanbin; Fent, Karl

    2016-02-01

    Environmental progestins are implicated in endocrine disruption in vertebrates. Additional targets that may be affected in organisms are poorly known. Here we report that progesterone (P4) and drospirenone (DRS) interfere with the photo-transduction cascade and circadian rhythm network in the eyes of zebrafish. Breeding pairs of adult zebrafish were exposed to P4 and DRS for 21 days with different measured concentrations of 7-742 ng/L and 99-13´650 ng/L, respectively. Of totally 10 key photo-transduction cascade genes analyzed, transcriptional levels of most were significantly up-regulated, or normal down-regulation was attenuated. Similarly, for some circadian rhythm genes, dose-dependent transcriptional alterations were also observed in the totally 33 genes analyzed. Significant alterations occurred even at environmental relevant levels of 7 ng/L P4. Different patterns were observed for these transcriptional alterations, of which, the nfil3 family displayed most significant changes. Furthermore, we demonstrate the importance of sampling time for the determination and interpretation of gene expression data, and put forward recommendations for sampling strategies to avoid false interpretations. Our results suggest that photo-transduction signals and circadian rhythm are potential targets for progestins. Further studies are required to assess alterations on the protein level, on physiology and behavior, as well as on implications in mammals.

  16. Diurnal cortisol rhythms, fatigue and psychosocial factors in five-year survivors of ovarian cancer.

    Science.gov (United States)

    Cuneo, Michaela G; Schrepf, Andrew; Slavich, George M; Thaker, Premal H; Goodheart, Michael; Bender, David; Cole, Steve W; Sood, Anil K; Lutgendorf, Susan K

    2017-10-01

    Fatigue is a challenge in ovarian cancer survivorship and greatly impacts quality of life. In other cancer populations, fatigue has been associated with abnormal diurnal cortisol patterns. However, little is known about biological and behavioral factors in 5+-year ovarian cancer survivors and potential mechanisms underlying persistent fatigue have not been investigated in this population. Moreover, relationships between neuroendocrine and psychosocial factors in 5+-year ovarian cancer survivors have not been studied. We addressed these issues by examining relationships between diurnal cortisol rhythms, fatigue, life stress, and social support in 30 survivors of ovarian cancer who were assessed at least 5 years (mean=6.20years) following their primary diagnosis. Flatter diurnal cortisol slopes were associated with higher levels of fatigue, suggesting a role for HPA-axis dysregulation in sustained fatigue experienced by survivors. Moreover, greater cumulative lifetime stressor exposure (p=0.023) and stressor severity (p=0.004) were associated with flatter diurnal cortisol slopes, while higher social attachment (p=0.001) was associated with steeper diurnal cortisol slopes. These findings suggest that ovarian cancer survivors with greater lifetime stress exposure or lower social attachment may be at increased risk for circadian rhythm disruption, which in turn is associated with fatigue. Future research should examine relationships of clinical stage and inflammatory cytokines to cortisol rhythms and fatigue in long-term ovarian cancer survivors, as well as investigating the clinical significance of abnormal diurnal cortisol profiles in this population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Beat Keeping in a Sea Lion as Coupled Oscillation: Implications for Comparative Understanding of Human Rhythm

    Directory of Open Access Journals (Sweden)

    Andrew A Rouse

    2016-06-01

    Full Text Available Human capacity for entraining movement to external rhythms—i.e., beat keeping—is ubiquitous, but its evolutionary history and neural underpinnings remain a mystery. Recent findings of entrainment to simple and complex rhythms in non-human animals pave the way for a novel comparative approach to assess the origins and mechanisms of rhythmic behavior. The most reliable non-human beat keeper to date is a California sea lion, Ronan, who was trained to match head movements to isochronous repeating stimuli and showed spontaneous generalization of this ability to novel tempos and to the complex rhythms of music. Does Ronan’s performance rely on the same neural mechanisms as human rhythmic behavior? In the current study, we presented Ronan with simple rhythmic stimuli at novel tempos. On some trials, we introduced perturbations, altering either tempo or phase in the middle of a presentation. Ronan quickly adjusted her behavior following all perturbations, recovering her consistent phase and tempo relationships to the stimulus within a few beats. Ronan’s performance was consistent with predictions of mathematical models describing coupled oscillation: a model relying solely on phase coupling strongly matched her behavior, and the model was further improved with the addition of period coupling. These findings are the clearest evidence yet for parity in human and non-human beat keeping and support the view that the human ability to perceive and move in time to rhythm may be rooted in broadly conserved neural mechanisms.

  18. The use of heart rate turbulence and heart rate variability in the assessment of autonomic regulation and circadian rhythm in patients with systemic lupus erythematosus without apparent heart disease.

    Science.gov (United States)

    Poliwczak, A R; Waszczykowska, E; Dziankowska-Bartkowiak, B; Koziróg, M; Dworniak, K

    2018-03-01

    Background Systemic lupus erythematosus is a progressive autoimmune disease. There are reports suggesting that patients even without overt signs of cardiovascular complications have impaired autonomic function. The aim of this study was to assess autonomic function using heart rate turbulence and heart rate variability parameters indicated in 24-hour ECG Holter monitoring. Methods Twenty-six women with systemic lupus erythematosus and 30 healthy women were included. Twenty-four hour ambulatory ECG-Holter was performed in home conditions. The basic parameters of heart rate turbulence and heart rate variability were calculated. The analyses were performed for the entire day and separately for daytime activity and night time rest. Results There were no statistically significant differences in the basic anthropometric parameters. The mean duration of disease was 11.52 ± 7.42. There was a statistically significant higher turbulence onset (To) value in patients with systemic lupus erythematosus, median To = -0.17% (minimum -1.47, maximum 3.0) versus To = -1.36% (minimum -4.53, maximum -0.41), P lupus erythematosus group than in the healthy controls, including SDANN and r-MSSD and p50NN. Concerning the morning activity and night resting periods, the results were similar as for the whole day. In the control group, higher values in morning activity were noted for parameters that characterise sympathetic activity, especially SDANN, and were significantly lower for parasympathetic parameters, including r-MSSD and p50NN, which prevailed at night. There were no statistically significant changes for systemic lupus erythematosus patients for p50NN and low and very low frequency. There was a positive correlation between disease duration and SDNN, R = 0.417; P < 0.05 and SDANN, R = 0.464; P < 0.05, a negative correlation between low/high frequency ratio and r-MSSD, R = -0.454; P < 0.05; p50NN, R = -0.435; P < 0.05 and high frequency

  19. Ethics and methods for biological rhythm research on animals and human beings.

    Science.gov (United States)

    Portaluppi, Francesco; Smolensky, Michael H; Touitou, Yvan

    2010-10-01

    This article updates the ethical standards and methods for the conduct of high-quality animal and human biological rhythm research, which should be especially useful for new investigators of the rhythms of life. The editors of Chronobiology International adhere to and endorse the Code of Conduct and Best Practice Guidelines of the Committee On Publication Ethics (COPE), which encourages communication of such updates at regular intervals in the journal. The journal accepts papers representing original work, no part of which was previously submitted for publication elsewhere, except as brief abstracts, as well as in-depth reviews. The majority of research papers published in Chronobiology International entails animal and human investigations. The editors and readers of the journal expect authors of submitted manuscripts to have made an important contribution to the research of biological rhythms and related phenomena using ethical methods/procedures and unbiased, accurate, and honest reporting of findings. Authors of scientific papers are required to declare all potential conflicts of interest. The journal and its editors endorse compliance of investigators to the Guide for the Care and Use of Laboratory Animals of the Institute for Laboratory Animal Research of the National Research Council, relating to the conduct of ethical research on laboratory and other animals, and the principles of the Declaration of Helsinki of the World Medical Association, relating to the conduct of ethical research on human beings. The peer review of manuscripts by Chronobiology International thus includes judgment as to whether or not the protocols and methods conform to ethical standards. Authors are expected to show mastery of the basic methods and procedures of biological rhythm research and proper statistical assessment of data, including the appropriate application of time series data analyses, as briefly reviewed in this article. The journal editors strive to consistently achieve

  20. Reducing language to rhythm: Amazonian Bora drummed language exploits speech rhythm for long-distance communication

    Science.gov (United States)

    Seifart, Frank; Meyer, Julien; Grawunder, Sven; Dentel, Laure

    2018-04-01

    Many drum communication systems around the world transmit information by emulating tonal and rhythmic patterns of spoken languages in sequences of drumbeats. Their rhythmic characteristics, in particular, have not been systematically studied so far, although understanding them represents a rare occasion for providing an original insight into the basic units of speech rhythm as selected by natural speech practices directly based on beats. Here, we analyse a corpus of Bora drum communication from the northwest Amazon, which is nowadays endangered with extinction. We show that four rhythmic units are encoded in the length of pauses between beats. We argue that these units correspond to vowel-to-vowel intervals with different numbers of consonants and vowel lengths. By contrast, aligning beats with syllables, mora or only vowel length yields inconsistent results. Moreover, we also show that Bora drummed messages conventionally select rhythmically distinct markers to further distinguish words. The two phonological tones represented in drummed speech encode only few lexical contrasts. Rhythm thus appears to crucially contribute to the intelligibility of drummed Bora. Our study provides novel evidence for the role of rhythmic structures composed of vowel-to-vowel intervals in the complex puzzle concerning the redundancy and distinctiveness of acoustic features embedded in speech.

  1. Rhythm- and Rate-Controlling Effects of Dronedarone in Patients With Atrial Fibrillation (from the ATHENA Trial)

    DEFF Research Database (Denmark)

    Page, Richard L; Connolly, Stuart J; Crijns, Harry J G M

    2011-01-01

    Dronedarone is a multi-channel-blocking drug for the treatment of patients with atrial fibrillation (AF) or atrial flutter (AFL) with rate- and rhythm-controlling properties. A Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone 400 mg b.i.d. for the Prevent......Dronedarone is a multi-channel-blocking drug for the treatment of patients with atrial fibrillation (AF) or atrial flutter (AFL) with rate- and rhythm-controlling properties. A Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone 400 mg b...... classified as having permanent AF or AFL. All electrical cardioversions were documented. The use of rate-controlling medications was equally distributed in the 2 treatment groups. The median time to first AF or AFL recurrence of patients in sinus rhythm at baseline was 498 days in placebo patients and 737......, dronedarone demonstrated both rhythm- and rate-controlling properties in ATHENA. These effects are likely to contribute to the reduction of important clinical outcomes observed in this trial....

  2. The role of the daily feeding rhythm in the regulation of the day/night rhythm in triglyceride secretion in rats

    NARCIS (Netherlands)

    Su, Yan; Foppen, Ewout; Mansur Machado, Frederico Sander; Fliers, Eric; Kalsbeek, A.

    2018-01-01

    Plasma triglyceride (TG) levels show a clear daily rhythm, however, thus far it is still unknown whether this rhythm results from a daily rhythm in TG production, TG uptake or both. Previous studies have shown that feeding activity affects plasma TG concentrations, but it is not clear how the daily

  3. Cortical layers, rhythms and BOLD signals.

    Science.gov (United States)

    Scheeringa, René; Fries, Pascal

    2017-11-03

    This review investigates how laminar fMRI can complement insights into brain function derived from the study of rhythmic neuronal synchronization. Neuronal synchronization in various frequency bands plays an important role in neuronal communication between brain areas, and it does so on the backbone of layer-specific interareal anatomical projections. Feedforward projections originate predominantly in supragranular cortical layers and terminate in layer 4, and this pattern is reflected in inter-laminar and interareal directed gamma-band influences. Thus, gamma-band synchronization likely subserves feedforward signaling. By contrast, anatomical feedback projections originate predominantly in infragranular layers and terminate outside layer 4, and this pattern is reflected in inter-laminar and interareal directed alpha- and/or beta-band influences. Thus, alpha-beta band synchronization likely subserves feedback signaling. Furthermore, these rhythms explain part of the BOLD signal, with independent contributions of alpha-beta and gamma. These findings suggest that laminar fMRI can provide us with a potentially useful method to test some of the predictions derived from the study of neuronal synchronization. We review central findings regarding the role of layer-specific neuronal synchronization for brain function, and regarding the link between neuronal synchronization and the BOLD signal. We discuss the role that laminar fMRI could play by comparing it to invasive and non-invasive electrophysiological recordings. Compared to direct electrophysiological recordings, this method provides a metric of neuronal activity that is slow and indirect, but that is uniquely non-invasive and layer-specific with potentially whole brain coverage. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Physiological basis for human autonomic rhythms

    Science.gov (United States)

    Eckberg, D. L.

    2000-01-01

    Oscillations of arterial pressures, heart periods, and muscle sympathetic nerve activity have been studied intensively in recent years to explore otherwise obscure human neurophysiological mechanisms. The best-studied rhythms are those occurring at breathing frequencies. Published evidence indicates that respiratory fluctuations of muscle sympathetic nerve activity and electrocardiographic R-R intervals result primarily from the action of a central 'gate' that opens during expiration and closes during inspiration. Parallel respiratory fluctuations of arterial pressures and R-R intervals are thought to be secondary to arterial baroreflex physiology: changes in systolic pressure provoke changes in the R-R interval. However, growing evidence suggests that these parallel oscillations result from the influence of respiration on sympathetic and vagal-cardiac motoneurones rather than from baroreflex physiology. There is a rapidly growing literature on the use of mathematical models of low- and high-frequency (respiratory) R-R interval fluctuations in characterizing instantaneous 'sympathovagal balance'. The case for this approach is based primarily on measurements made with patients in upright tilt. However, the strong linear relation between such measures as the ratio of low- to high-frequency R-R interval oscillations and the angle of the tilt reflects exclusively the reductions of the vagal (high-frequency) component. As the sympathetic component does not change in tilt, the low- to high-frequency R-R interval ratio provides no proof that sympathetic activity increases. Moreover, the validity of extrapolating from measurements performed during upright tilt to measurements during supine rest has not been established. Nonetheless, it is clear that measures of heart rate variability provide important prognostic information in patients with cardiovascular diseases. It is not known whether reduced heart rate variability is merely a marker for the severity of disease or a

  5. Circadian Rhythms in Floral Scent Emission.

    Science.gov (United States)

    Fenske, Myles P; Imaizumi, Takato

    2016-01-01

    To successfully recruit pollinators, plants often release attractive floral scents at specific times of day to coincide with pollinator foraging. This timing of scent emission is thought to be evolutionarily beneficial to maximize resource efficiency while attracting only useful pollinators. Temporal regulation of scent emission is tied to the activity of the specific metabolic pathways responsible for scent production. Although floral volatile profiling in various plants indicated a contribution by the circadian clock, the mechanisms by which the circadian clock regulates timing of floral scent emission remained elusive. Recent studies using two species in the Solanaceae family provided initial insight into molecular clock regulation of scent emission timing. In Petunia hybrida, the floral volatile benzenoid/phenylpropanoid (FVBP) pathway is the major metabolic pathway that produces floral volatiles. Three MYB-type transcription factors, ODORANT 1 (ODO1), EMISSION OF BENZENOIDS I (EOBI), and EOBII, all of which show diurnal rhythms in mRNA expression, act as positive regulators for several enzyme genes in the FVBP pathway. Recently, in P. hybrida and Nicotiana attenuata, homologs of the Arabidopsis clock gene LATE ELONGATED HYPOCOTYL (LHY) have been shown to have a similar role in the circadian clock in these plants, and to also determine the timing of scent emission. In addition, in P. hybrida, PhLHY directly represses ODO1 and several enzyme genes in the FVBP pathway during the morning as an important negative regulator of scent emission. These findings facilitate our understanding of the relationship between a molecular timekeeper and the timing of scent emission, which may influence reproductive success.

  6. Circadian rhythms in floral scent emission

    Directory of Open Access Journals (Sweden)

    Myles eFenske

    2016-04-01

    Full Text Available To successfully recruit pollinators, plants often release attractive floral scents at specific times of day to coincide with pollinator foraging. This timing of scent emission is thought to be evolutionarily beneficial to maximize resource efficiency while attracting only useful pollinators. Temporal regulation of scent emission is tied to the activity of the specific metabolic pathways responsible for scent production. Although floral volatile profiling in various plants indicated a contribution by the circadian clock, the mechanisms by which the circadian clock regulates timing of floral scent emission remained elusive. Recent studies using two species in the Solanaceae family provided initial insight into molecular clock regulation of scent emission timing. In Petunia hybrida, the benzenoid/phenylpropanoid (FVBP pathway is the major metabolic pathway that produces floral volatiles. Three MYB-type transcription factors, ODORANT1 (ODO1, EMISSION OF BENZENOIDS I (EOBI, and EOBII, all of which show diurnal rhythms in mRNA expression, act as positive regulators for several enzyme genes in the FVBP pathway. Recently, in P. hybrida and Nicotiana attenuata, homologs of the Arabidopsis clock gene LATE ELONGATED HYPOCOTYL (LHY have been shown to have a similar role in the circadian clock in these plants, and to also determine the timing of scent emission. In addition, in P. hybrida, PhLHY directly represses ODO1 and several enzyme genes in the FVBP pathway during the morning as an important negative regulator of scent emission. These findings facilitate our understanding of the relationship between a molecular timekeeper and the timing of scent emission, which may influence reproductive success.

  7. Wettability measurements of irregular shapes with Wilhelmy plate method

    Science.gov (United States)

    Park, Jaehyung; Pasaogullari, Ugur; Bonville, Leonard

    2018-01-01

    One of the most accurate methods for measuring the dynamic contact angle of liquids on solid surfaces is the Wilhelmy plate method. This method generally requires the use of rectangular samples having a constant perimeter in the liquid during advancing and receding cycles. A new formulation based on the Wilhelmy force balance equation to determine the contact angle for plate samples with irregular shapes has been developed. This method employs a profile plot obtained from an optical image to determine the perimeter (i.e. wetted length) of the sample as a function of the immersion depth. The raw force data measured by the force tensiometer is manipulated using the profile plot and the Wilhelmy equation to determine the wetting force and consequently advancing and the receding contact angle. This method is verified with both triangular and irregular PTFE samples in water, and measured contact angles are in good agreement with results from conventional regular shaped samples with a constant perimeter.

  8. Rocket measurements of electron density irregularities during MAC/SINE

    Science.gov (United States)

    Ulwick, J. C.

    1989-01-01

    Four Super Arcas rockets were launched at the Andoya Rocket Range, Norway, as part of the MAC/SINE campaign to measure electron density irregularities with high spatial resolution in the cold summer polar mesosphere. They were launched as part of two salvos: the turbulent/gravity wave salvo (3 rockets) and the EISCAT/SOUSY radar salvo (one rocket). In both salvos meteorological rockets, measuring temperature and winds, were also launched and the SOUSY radar, located near the launch site, measured mesospheric turbulence. Electron density irregularities and strong gradients were measured by the rocket probes in the region of most intense backscatter observed by the radar. The electron density profiles (8 to 4 on ascent and 4 on descent) show very different characteristics in the peak scattering region and show marked spatial and temporal variability. These data are intercompared and discussed.

  9. The scholarly rebellion of the early Baker Street Irregulars

    Directory of Open Access Journals (Sweden)

    George Mills

    2017-03-01

    Full Text Available This work provides and analyzes an early institutional history of the pioneering Sherlock Holmes American fan club, the Baker Street Irregulars (BSI. Using the publications and records of these devoted Sherlockians, I track the BSI's development from a speakeasy gathering in 1934 to a national organization by the mid-1940s. This growth was built on a foundation of Victorian nostalgia and playful humor. Yet at the same time the members of the Irregulars took their fandom seriously, producing Sherlockian scholarship and creating an infrastructure of journals, conferences, and credentialing that directly mimicked the academy. They positioned themselves in contrast to prevailing scholarly practices of the period, such as New Criticism. I trace both how their fan practices developed over time and how this conflict with the academy led to many of the BSI's defining characteristics.

  10. Constructing C1 Continuous Surface on Irregular Quad Meshes

    Institute of Scientific and Technical Information of China (English)

    HE Jun; GUO Qiang

    2013-01-01

    A new method is proposed for surface construction on irregular quad meshes as extensions to uniform B-spline surfaces. Given a number of control points, which form a regular or irregular quad mesh, a weight function is constructed for each control point. The weight function is defined on a local domain and is C1 continuous. Then the whole surface is constructed by the weighted combination of all the control points. The property of the new method is that the surface is defined by piecewise C1 bi-cubic rational parametric polynomial with each quad face. It is an extension to uniform B-spline surfaces in the sense that its definition is an analogy of the B-spline surface, and it produces a uniform bi-cubic B-spline surface if the control mesh is a regular quad mesh. Examples produced by the new method are also included.

  11. Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

    Science.gov (United States)

    2007-09-01

    the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

  12. Active Absorption of Irregular Gravity Waves in BEM-Models

    DEFF Research Database (Denmark)

    Brorsen, Michael; Frigaard, Peter

    1992-01-01

    The boundary element method is applied to the computation of irregular gravity waves. The boundary conditions at the open boundaries are obtained by a digital filtering technique, where the surface elevations in front of the open boundary are filtered numerically yielding the velocity to be presc...... to be prescribed at the boundary. By numerical examples it is shown that well designed filters can reduce the wave reflection to a few per cent over a frequency range corresponding to a Jonswap spectrum....

  13. Computing Homology Group Generators of Images Using Irregular Graph Pyramids

    OpenAIRE

    Peltier , Samuel; Ion , Adrian; Haxhimusa , Yll; Kropatsch , Walter; Damiand , Guillaume

    2007-01-01

    International audience; We introduce a method for computing homology groups and their generators of a 2D image, using a hierarchical structure i.e. irregular graph pyramid. Starting from an image, a hierarchy of the image is built, by two operations that preserve homology of each region. Instead of computing homology generators in the base where the number of entities (cells) is large, we first reduce the number of cells by a graph pyramid. Then homology generators are computed efficiently on...

  14. Analysis of irregular opacities of silicosis using computed tomography

    International Nuclear Information System (INIS)

    Maeda, Atsushi; Shida, Hisao; Chiyotani, Keizo; Saito, Kenichi; Mishina, Michihito

    1983-01-01

    Classification in used to codify Chest CT images of abnormalities of the lung in a simple reproducible manner. Simbols to record CT features of importance are listed. We applied CT to 92 cases of silicosis and roentgenological analysis was performed. Bullae, honeycombing, cavity, emphysema, pleural thickning and calcification were more clearly demonstrated in CT images than routine chest roentgenograms. Irregular opacities were considered to be a combined profusion of small round and streak or strand. (author)

  15. [Psychoeducation and interpersonal and social rhythm therapy for bipolar disorder].

    Science.gov (United States)

    Mizushima, Hiroko

    2011-01-01

    In treating bipolar disorder, specific psychotherapies in adjunct to pharmacotherapy have been shown to be effective in preventing new episodes and treating depressive episodes. Among those, interpersonal and social rhythm therapy (IPSRT) developed by Frank, amalgamation of interpersonal psychotherapy (IPT) with behavioral therapy focused on social rhythm has been shown to be an efficacious adjunct to mediation in preventing new episodes in bipolar I patients and in treating depression in bipolar I arid II disorder. IPSRT has also been shown to enhance total functioning, relationship functioning and life satisfaction among patients with bipolar disorder, even after pretreatment functioning and concurrent depression were covaried. IPSRT was designed to directly address the major pathways to recurrence in bipolar disorder, namely medication nonadherence, stressful life events, and disruptions in social rhythms. IPT, originated by Klerman et al., is a strategic time-limited psychotherapy focused on one or two of four current interpersonal problem areas (ie, grief, interpersonal role disputes, role transitions, and interpersonal dificits). In IPSRT, the fifth problem area "grief for the lost healthy self" has been added in order to promote acceptance of the diagnosis and the need for life-long treatment. Social rhythm therapy is a behavioral approach aiming at increasing regularity of social rhythms using the Social Rhythm Metric (SRM), a chart to record daily social activities including how stimulating they were, developed from observation that disruptions in social rhythms often trigger affective episodes in patients with bipolar disorder. IPSRT also appears to be a promising intervention for a subset of individuals with bipolar II depression as monotherapy for the acute treatment.

  16. Rhythms of mammalian body temperature can sustain peripheral circadian clocks.

    Science.gov (United States)

    Brown, Steven A; Zumbrunn, Gottlieb; Fleury-Olela, Fabienne; Preitner, Nicolas; Schibler, Ueli

    2002-09-17

    Low-amplitude temperature oscillations can entrain the phase of circadian rhythms in several unicellular and multicellular organisms, including Neurospora and Drosophila. Because mammalian body temperature is subject to circadian variations of 1 degrees C-4 degrees C, we wished to determine whether these temperature cycles could serve as a Zeitgeber for circadian gene expression in peripheral cell types. In RAT1 fibroblasts cultured in vitro, circadian gene expression could be established by a square wave temperature rhythm with a (Delta)T of 4 degrees C (12 hr 37 degrees C/12 hr 33 degrees C). To examine whether natural body temperature rhythms can also affect circadian gene expression, we first measured core body temperature cycles in the peritoneal cavities of mice by radiotelemetry. We then reproduced these rhythms with high precision in the liquid medium of cultured fibroblasts for several days by means of a homemade computer-driven incubator. While these "in vivo" temperature rhythms were incapable of establishing circadian gene expression de novo, they could maintain previously induced rhythms for multiple days; by contrast, the rhythms of control cells kept at constant temperature rapidly dampened. Moreover, circadian oscillations of environmental temperature could reentrain circadian clocks in the livers of mice, probably via the changes they imposed upon both body temperature and feeding behavior. Interestingly, these changes in ambient temperature did not affect the phase of the central circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus. We postulate that both endogenous and environmental temperature cycles can participate in the synchronization of peripheral clocks in mammals.

  17. Chronotype influences activity circadian rhythm and sleep: differences in sleep quality between weekdays and weekend.

    Science.gov (United States)

    Vitale, Jacopo A; Roveda, Eliana; Montaruli, Angela; Galasso, Letizia; Weydahl, Andi; Caumo, Andrea; Carandente, Franca

    2015-04-01

    Several studies have shown the differences among chronotypes in the circadian rhythm of different physiological variables. Individuals show variation in their preference for the daily timing of activity; additionally, there is an association between chronotype and sleep duration/sleep complaints. Few studies have investigated sleep quality during the week days and weekends in relation to the circadian typology using self-assessment questionnaires or actigraphy. The purpose of this study was to use actigraphy to assess the relationship between the three chronotypes and the circadian rhythm of activity levels and to determine whether sleep parameters respond differently with respect to time (weekdays versus the weekend) in Morning-types (M-types), Neither-types (N-types) and Evening-types (E-types). The morningness-eveningness questionnaire (MEQ) was administered to 502 college students to determine their chronotypes. Fifty subjects (16 M-types, 15 N-types and 19 E-types) were recruited to undergo a 7-days monitoring period with an actigraph (Actiwacth® actometers, CNT, Cambridge, UK) to evaluate their sleep parameters and the circadian rhythm of their activity levels. To compare the amplitude and the acrophase among the three chronotypes, we used a one-way ANOVA followed by the Tukey-Kramer post-hoc test. To compare the Midline Estimating Statistic of Rhythm (MESOR) among the three chronotypes, we used a Kruskal-Wallis non-parametric test followed by pairwise comparisons that were performed using Dunn's procedure with a Bonferroni correction for multiple comparisons. The analysis of each sleep parameter was conducted using the mixed ANOVA procedure. The results showed that the chronotype was influenced by sex (χ(2) with p = 0.011) and the photoperiod at birth (χ(2) with p circadian rhythm of activity levels was influenced by the chronotype; second, the chronotype had a significant effect on sleep parameters: the E-types had a reduced sleep quality and

  18. Backscatter measurements of 11-cm equatorial spread-F irregularities

    International Nuclear Information System (INIS)

    Tsunoda, R.T.

    1980-01-01

    In the equatorial F-region ionosphere, a turbulent cascade process has been found to exist that extends from irregularity spatial wavelengths longer than tens of kilometers down to wavelengths as short as 36 cm. To investigate the small-scale regime of wavelengths less than 36 cm, an equatorial radar experiment was conducted using a frequency of 1320 MHz that corresponds to an irregularity wavelength of 11 cm. The first observations of radar backscatter from 11-cm field-aligned irregularities (FAI) are described. These measurements extend the spatial wavelength regime of F-region FAI to lengths that approach both electron gyroradius and the Debye length. Agreement of these results with the theory of high-frequency drift waves suggests that these observations may be unique to the equatorial ionosphere. That is, the requirement of low electron densities for which the theroy calls may preclude the existence of 11-cm FAI elsewhere in the F-region ionosphere, except in equatorial plasma bubbles

  19. [Comparision of Different Methods of Area Measurement in Irregular Scar].

    Science.gov (United States)

    Ran, D; Li, W J; Sun, Q G; Li, J Q; Xia, Q

    2016-10-01

    To determine a measurement standard of irregular scar area by comparing the advantages and disadvantages of different measurement methods in measuring same irregular scar area. Irregular scar area was scanned by digital scanning and measured by coordinate reading method, AutoCAD pixel method, Photoshop lasso pixel method, Photoshop magic bar filled pixel method and Foxit PDF reading software, and some aspects of these methods such as measurement time, repeatability, whether could be recorded and whether could be traced were compared and analyzed. There was no significant difference in the scar areas by the measurement methods above. However, there was statistical difference in the measurement time and repeatability by one or multi performers and only Foxit PDF reading software could be traced back. The methods above can be used for measuring scar area, but each one has its advantages and disadvantages. It is necessary to develop new measurement software for forensic identification. Copyright© by the Editorial Department of Journal of Forensic Medicine

  20. Seismic performance for vertical geometric irregularity frame structures

    Science.gov (United States)

    Ismail, R.; Mahmud, N. A.; Ishak, I. S.

    2018-04-01

    This research highlights the result of vertical geometric irregularity frame structures. The aid of finite element analysis software, LUSAS was used to analyse seismic performance by focusing particularly on type of irregular frame on the differences in height floors and continued in the middle of the building. Malaysia’s building structures were affected once the earthquake took place in the neighbouring country such as Indonesia (Sumatera Island). In Malaysia, concrete is widely used in building construction and limited tension resistance to prevent it. Analysing structural behavior with horizontal and vertical static load is commonly analyses by using the Plane Frame Analysis. The case study of this research is to determine the stress and displacement in the seismic response under this type of irregular frame structures. This study is based on seven-storey building of Clinical Training Centre located in Sungai Buloh, Selayang, Selangor. Since the largest earthquake occurs in Acheh, Indonesia on December 26, 2004, the data was recorded and used in conducting this research. The result of stress and displacement using IMPlus seismic analysis in LUSAS Modeller Software under the seismic response of a formwork frame system states that the building is safe to withstand the ground and in good condition under the variation of seismic performance.

  1. Irregular analytical errors in diagnostic testing - a novel concept.

    Science.gov (United States)

    Vogeser, Michael; Seger, Christoph

    2018-02-23

    In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such a setting, any individual sample is not under individual quality control. The quality control measurements act only at the batch level. Quantitative or qualitative data derived for many effects and interferences associated with an individual diagnostic sample can compromise any analyte. It is obvious that a process for a quality-control-sample-based approach of quality assurance is not sensitive to such errors. To address the potential causes and nature of such analytical interference in individual samples more systematically, we suggest the introduction of a new term called the irregular (individual) analytical error. Practically, this term can be applied in any analytical assay that is traceable to a reference measurement system. For an individual sample an irregular analytical error is defined as an inaccuracy (which is the deviation from a reference measurement procedure result) of a test result that is so high it cannot be explained by measurement uncertainty of the utilized routine assay operating within the accepted limitations of the associated process quality control measurements. The deviation can be defined as the linear combination of the process measurement uncertainty and the method bias for the reference measurement system. Such errors should be coined irregular analytical errors of the individual sample. The measurement result is compromised either by an irregular effect associated with the individual composition (matrix) of the sample or an individual single sample associated processing error in the analytical process. Currently, the availability of reference measurement procedures is still highly limited, but LC

  2. Stromal haze, myofibroblasts, and surface irregularity after PRK.

    Science.gov (United States)

    Netto, Marcelo V; Mohan, Rajiv R; Sinha, Sunilima; Sharma, Ajay; Dupps, William; Wilson, Steven E

    2006-05-01

    The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze. Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups: [see table in text]. Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr or 4 weeks after surgery and histochemical analysis was performed on corneas for apoptosis (TUNEL assay), myofibroblast marker alpha-smooth muscle actin (SMA), and integrin alpha4 to delineate the epithelial basement membrane. Slit-lamp grading revealed severe haze formation in corneas in groups IV and VI, with significantly less haze in groups II, III, and VII and insignificant haze compared with the unwounded control in groups I and V. Analysis of SMA staining at 4 weeks after surgery, the approximate peak of haze formation in rabbits, revealed low myofibroblast formation in group I (1.2+/-0.2 cells/400x field) and group V (1.8+/-0.4), with significantly more in groups II (3.5+/-1.8), III (6.8+/-1.6), VII (7.9+/-3.8), IV (12.4+/-4.2) and VI (14.6+/-5.1). The screened groups were significantly different from each other (p PRK groups. The -9.0 diopter PRK group VI had significantly more myofibroblast generation than the -9.0 diopter PRK with PTK-smoothing group VII (p PRK and the level of stromal surface irregularity. PTK-smoothing with methylcellulose was an effective method to reduce stromal surface irregularity and decreased both haze and associated myofibroblast density. We hypothesize that stromal surface irregularity after PRK for high myopia results in defective basement membrane

  3. Women with minor menstrual irregularities have increased risk of preeclampsia and low birthweight in spontaneous pregnancies

    DEFF Research Database (Denmark)

    Bonnesen, Barbara; Oddgeirsdóttir, Hanna L; Naver, Klara Vinsand

    2016-01-01

    INTRODUCTION: Very few studies describe the obstetric and neonatal outcome of spontaneous pregnancies in women with irregular menstrual cycles. However, menstrual cycle irregularities are common and may be associated with increased risk, and women who develop pregnancy complications more frequent...

  4. Are circadian rhythms new pathways to understand Autism Spectrum Disorder?

    Science.gov (United States)

    Geoffray, M-M; Nicolas, A; Speranza, M; Georgieff, N

    2016-11-01

    Autism Spectrum Disorder (ASD) is a frequent neurodevelopmental disorder. ASD is probably the result of intricate interactions between genes and environment altering progressively the development of brain structures and functions. Circadian rhythms are a complex intrinsic timing system composed of almost as many clocks as there are body cells. They regulate a variety of physiological and behavioral processes such as the sleep-wake rhythm. ASD is often associated with sleep disorders and low levels of melatonin. This first point raises the hypothesis that circadian rhythms could have an implication in ASD etiology. Moreover, circadian rhythms are generated by auto-regulatory genetic feedback loops, driven by transcription factors CLOCK and BMAL1, who drive transcription daily patterns of a wide number of clock-controlled genes (CCGs) in different cellular contexts across tissues. Among these, are some CCGs coding for synapses molecules associated to ASD susceptibility. Furthermore, evidence emerges about circadian rhythms control of time brain development processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Rhythms in the endocrine system of fish: a review.

    Science.gov (United States)

    Cowan, Mairi; Azpeleta, Clara; López-Olmeda, Jose Fernando

    2017-12-01

    The environment which living organisms inhabit is not constant and many factors, such as light, temperature, and food availability, display cyclic and predictable variations. To adapt to these cyclic changes, animals present biological rhythms in many of their physiological variables, timing their functions to occur when the possibility of success is greatest. Among these variables, many endocrine factors have been described as displaying rhythms in vertebrates. The aim of the present review is to provide a thorough review of the existing knowledge on the rhythms of the endocrine system of fish by examining the hormones that show rhythmicity, how environmental factors control these rhythms and the variation in the responses of the endocrine system depending on the time of the day. We mainly focused on the hypothalamic-pituitary axis, which can be considered as the master axis of the endocrine system of vertebrates and regulates a great variety of functions, including reproduction, growth, metabolism, energy homeostasis, stress response, and osmoregulation. In addition, the rhythms of other hormones, such as melatonin and the factors, produced in the gastrointestinal system of fish are reviewed.

  6. Intracerebral evidence of rhythm transform in the human auditory cortex.

    Science.gov (United States)

    Nozaradan, Sylvie; Mouraux, André; Jonas, Jacques; Colnat-Coulbois, Sophie; Rossion, Bruno; Maillard, Louis

    2017-07-01

    Musical entrainment is shared by all human cultures and the perception of a periodic beat is a cornerstone of this entrainment behavior. Here, we investigated whether beat perception might have its roots in the earliest stages of auditory cortical processing. Local field potentials were recorded from 8 patients implanted with depth-electrodes in Heschl's gyrus and the planum temporale (55 recording sites in total), usually considered as human primary and secondary auditory cortices. Using a frequency-tagging approach, we show that both low-frequency (30 Hz) neural activities in these structures faithfully track auditory rhythms through frequency-locking to the rhythm envelope. A selective gain in amplitude of the response frequency-locked to the beat frequency was observed for the low-frequency activities but not for the high-frequency activities, and was sharper in the planum temporale, especially for the more challenging syncopated rhythm. Hence, this gain process is not systematic in all activities produced in these areas and depends on the complexity of the rhythmic input. Moreover, this gain was disrupted when the rhythm was presented at fast speed, revealing low-pass response properties which could account for the propensity to perceive a beat only within the musical tempo range. Together, these observations show that, even though part of these neural transforms of rhythms could already take place in subcortical auditory processes, the earliest auditory cortical processes shape the neural representation of rhythmic inputs in favor of the emergence of a periodic beat.

  7. Scapulohumeral rhythm in shoulders with reverse shoulder arthroplasty.

    Science.gov (United States)

    Walker, David; Matsuki, Keisuke; Struk, Aimee M; Wright, Thomas W; Banks, Scott A

    2015-07-01

    Little is known about kinematic function of reverse total shoulder arthroplasty (RTSA). Scapulohumeral rhythm (SHR) is a common metric for assessing muscle function and shoulder joint motion. The purpose of this study was to compare SHR in shoulders with RTSA to normal shoulders. Twenty-eight subjects, more than 12 months after unilateral RTSA, were recruited for an Institutional Review Board-approved study. Subjects performed arm abduction in the coronal plane with and without a 1.4-kg hand-held weight. Three-dimensional model-image registration techniques were used to measure orientation and position for the humerus and scapula from fluoroscopic images. Analysis of variance and Tukey tests were used to assess groupwise and pairwise differences. SHR in RTSA shoulders (1.3:1) was significantly lower than in normal shoulders (3:1). Below 30° abduction, RTSA and normal shoulders show a wide range of SHR (1.3:1 to 17:1). Above 30° abduction, SHR in RTSA shoulders was 1.3:1 for unweighted abduction and 1.3:1 for weighted abduction. Maximum RTSA shoulder abduction in weighted trials was lower than in unweighted trials. SHR variability in RTSA shoulders decreased with increasing arm elevation. RTSA shoulders show kinematics that are significantly different from normal shoulders. SHR in RTSA shoulders was significantly lower than in normal shoulders, indicating that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm. With these observations, it may be possible to improve rehabilitation protocols, with particular attention to the periscapular muscles, and implant design or placement to optimize functional outcomes in shoulders with RTSA. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  8. Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section

    Directory of Open Access Journals (Sweden)

    Chaolong Jia

    2014-01-01

    Full Text Available Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described.

  9. Effects of the I-kr-blocker almokalant and predictors of conversion of chronic atrial tachyarrhythmias to sinus rhythm. A prospective study

    NARCIS (Netherlands)

    Houltz, B; Darpo, B; Swedberg, K; Blomstrom, P; Brachmann, J; Crijns, Harry J. G. M.; Jensen, Steen M.; Svernhage, E; Vallin, H; Edvardsson, N

    Purpose: To assess the efficacy of the I-kr-blocker almokalant attempting to convert chronic atrial tachyarrhythmias, and to find predictors of conversion, to sinus rhythm. Methods: The electrophysiological effects of a 6-hour infusion of almokalant, to a total dose of 25 +/- 4 mg, were assessed by

  10. Sleep and circadian rhythm disruption in neuropsychiatric illness.

    Science.gov (United States)

    Jagannath, Aarti; Peirson, Stuart N; Foster, Russell G

    2013-10-01

    Sleep and circadian rhythm disruption (SCRD) is a common feature in many neuropsychiatric diseases including schizophrenia, bipolar disorder and depression. Although the precise mechanisms remain unclear, recent evidence suggests that this comorbidity is not simply a product of medication or an absence of social routine, but instead reflects commonly affected underlying pathways and mechanisms. For example, several genes intimately involved in the generation and regulation of circadian rhythms and sleep have been linked to psychiatric illness. Further, several genes linked to mental illness have recently been shown to also play a role in normal sleep and circadian behaviour. Here we describe some of the emerging common mechanisms that link circadian rhythms, sleep and SCRD in severe mental illnesses. A deeper understanding of these links will provide not only a greater understanding of disease mechanisms, but also holds the promise of novel avenues for therapeutic intervention. Copyright © 2013. Published by Elsevier Ltd.

  11. Circadian rhythms, time-restricted feeding, and healthy aging.

    Science.gov (United States)

    Manoogian, Emily N C; Panda, Satchidananda

    2017-10-01

    Circadian rhythms optimize physiology and health by temporally coordinating cellular function, tissue function, and behavior. These endogenous rhythms dampen with age and thus compromise temporal coordination. Feeding-fasting patterns are an external cue that profoundly influence the robustness of daily biological rhythms. Erratic eating patterns can disrupt the temporal coordination of metabolism and physiology leading to chronic diseases that are also characteristic of aging. However, sustaining a robust feeding-fasting cycle, even without altering nutrition quality or quantity, can prevent or reverse these chronic diseases in experimental models. In humans, epidemiological studies have shown erratic eating patterns increase the risk of disease, whereas sustained feeding-fasting cycles, or prolonged overnight fasting, is correlated with protection from breast cancer. Therefore, optimizing the timing of external cues with defined eating patterns can sustain a robust circadian clock, which may prevent disease and improve prognosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Recent Advances in Circadian Rhythms in Cardiovascular System

    Directory of Open Access Journals (Sweden)

    Lihong eChen

    2015-04-01

    Full Text Available Growing evidence shows that intrinsic circadian clocks are tightly related to cardiovascular functions. The diurnal changes in blood pressure and heart rate are well known circadian rhythms. Endothelial function, platelet aggregation and thrombus formation exhibit circadian changes as well. The onset of many cardiovascular diseases (CVDs or events, such as myocardial infarction, stroke, arrhythmia, and sudden cardiac death, also exhibits temporal trends. Furthermore, there is strong evidence from animal models and epidemiological studies showing that disruption of circadian rhythms is a significant risk factor for many CVDs, and the intervention of CVDs may have a time dependent effect. In this mini review, we summarized recent advances in our understanding of the relationship between circadian rhythm and cardiovascular physiology and diseases including blood pressure regulation and myocardial infarction.

  13. Circadian Rhythm Sleep-Wake Disorders in Older Adults.

    Science.gov (United States)

    Kim, Jee Hyun; Duffy, Jeanne F

    2018-03-01

    The timing, duration, and consolidation of sleep result from the interaction of the circadian timing system with a sleep-wake homeostatic process. When aligned and functioning optimally, this allows wakefulness throughout the day and a long consolidated sleep episode at night. Mismatch between the desired timing of sleep and the ability to fall and remain asleep is a hallmark of the circadian rhythm sleep-wake disorders. This article discusses changes in circadian regulation of sleep with aging; how age influences the prevalence, diagnosis, and treatment of circadian rhythm sleep-wake disorders; and how neurologic diseases in older patients affect circadian rhythms and sleep. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Core temperature rhythms in normal and tumor-bearing mice.

    Science.gov (United States)

    Griffith, D J; Busot, J C; Lee, W E; Djeu, D J

    1993-01-01

    The core temperature temporal behavior of DBA/2 mice (11 normal and 13 with an ascites tumor) was studied using surgically implanted radio telemetry transmitters. Normal mice continuously displayed a stable 24 hour temperature rhythm. Tumor-bearers displayed a progressive deterioration of the temperature rhythm following inoculation with tumor cells. While such disruptions have been noted by others, details on the dynamics of the changes have been mostly qualitative, often due to time-averaging or steady-state analysis of the data. The present study attempts to quantify the dynamics of the disruption of temperature rhythm (when present) by continuously monitoring temperatures over periods up to a month. Analysis indicated that temperature regulation in tumor-bearers was adversely affected during the active period only. Furthermore, it appears that the malignancy may be influencing temperature regulation via pathways not directly attributable to the energy needs of the growing tumor.

  15. Rhythm information represented in the fronto-parieto-cerebellar motor system.

    Science.gov (United States)

    Konoike, Naho; Kotozaki, Yuka; Miyachi, Shigehiro; Miyauchi, Carlos Makoto; Yomogida, Yukihito; Akimoto, Yoritaka; Kuraoka, Koji; Sugiura, Motoaki; Kawashima, Ryuta; Nakamura, Katsuki

    2012-10-15

    Rhythm is an essential element of human culture, particularly in language and music. To acquire language or music, we have to perceive the sensory inputs, organize them into structured sequences as rhythms, actively hold the rhythm information in mind, and use the information when we reproduce or mimic the same rhythm. Previous brain imaging studies have elucidated brain regions related to the perception and production of rhythms. However, the neural substrates involved in the working memory of rhythm remain unclear. In addition, little is known about the processing of rhythm information from non-auditory inputs (visual or tactile). Therefore, we measured brain activity by functional magnetic resonance imaging while healthy subjects memorized and reproduced auditory and visual rhythmic information. The inferior parietal lobule, inferior frontal gyrus, supplementary motor area, and cerebellum exhibited significant activations during both encoding and retrieving rhythm information. In addition, most of these areas exhibited significant activation also during the maintenance of rhythm information. All of these regions functioned in the processing of auditory and visual rhythms. The bilateral inferior parietal lobule, inferior frontal gyrus, supplementary motor area, and cerebellum are thought to be essential for motor control. When we listen to a certain rhythm, we are often stimulated to move our body, which suggests the existence of a strong interaction between rhythm processing and the motor system. Here, we propose that rhythm information may be represented and retained as information about bodily movements in the supra-modal motor brain system. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Circadian melatonin rhythm and excessive daytime sleepiness in Parkinson disease.

    Science.gov (United States)

    Videnovic, Aleksandar; Noble, Charleston; Reid, Kathryn J; Peng, Jie; Turek, Fred W; Marconi, Angelica; Rademaker, Alfred W; Simuni, Tanya; Zadikoff, Cindy; Zee, Phyllis C

    2014-04-01

    Diurnal fluctuations of motor and nonmotor symptoms and a high prevalence of sleep-wake disturbances in Parkinson disease (PD) suggest a role of the circadian system in the modulation of these symptoms. However, surprisingly little is known regarding circadian function in PD and whether circadian dysfunction is involved in the development of sleep-wake disturbances in PD. To determine the relationship between the timing and amplitude of the 24-hour melatonin rhythm, a marker of endogenous circadian rhythmicity, with self-reported sleep quality, the severity of daytime sleepiness, and disease metrics. A cross-sectional study from January 1, 2009, through December 31, 2012, of 20 patients with PD receiving stable dopaminergic therapy and 15 age-matched control participants. Both groups underwent blood sampling for the measurement of serum melatonin levels at 30-minute intervals for 24 hours under modified constant routine conditions at the Parkinson's Disease and Movement Disorders Center of Northwestern University. Twenty-four hour monitoring of serum melatonin secretion. Clinical and demographic data, self-reported measures of sleep quality (Pittsburgh Sleep Quality Index) and daytime sleepiness (Epworth Sleepiness Scale), and circadian markers of the melatonin rhythm, including the amplitude, area under the curve (AUC), and phase of the 24-hour rhythm. Patients with PD had blunted circadian rhythms of melatonin secretion compared with controls; the amplitude of the melatonin rhythm and the 24-hour AUC for circulating melatonin levels were significantly lower in PD patients (P hour melatonin AUC (P = .001). Disease duration, Unified Parkinson's Disease Rating Scale scores, levodopa equivalent dose, and global Pittsburgh Sleep Quality Index score in the PD group were not significantly related to measures of the melatonin circadian rhythm. Circadian dysfunction may underlie excessive sleepiness in PD. The nature of this association needs to be explored further

  17. Is there an endogenous tidal foraging rhythm in marine iguanas?

    Science.gov (United States)

    Wikelski, M; Hau, M

    1995-12-01

    As strictly herbivorous reptiles, Galápagos marine iguanas graze on algae in the intertidal areas during low tide. Daily foraging rhythms were observed on two islands during 3 years to determine the proximate factors underlying behavioral synchrony with the tides. Marine iguanas walked to their intertidal foraging grounds from far-off resting areas in anticipation of the time of low tide. Foraging activity was restricted to daytime, resulting in a complex bitidal rhythm including conspicuous switches from afternoon foraging to foraging during the subsequent morning when low tide occurred after dusk. The animals anticipated the daily low tide by a maximum of 4 h. The degree of anticipation depended on environmental parameters such as wave action and food supply. "Early foragers" survived in greater numbers than did animals arriving later at foraging sites, a result indicating selection pressure on the timing of anticipation. The timing of foraging trips was better predicted by the daily changes in tabulated low tide than it was by the daily changes in actual exposure of the intertidal foraging flats, suggesting an endogenous nature of the foraging rhythms. Endogenous rhythmicity would also explain why iguanas that had spontaneously fasted for several days nevertheless went foraging at the "right" time of day. A potential lunar component of the foraging rhythmicity of marine iguanas showed up in their assemblage on intertidal rocks during neap tide nights. This may indicate that iguanas possessed information on the semi-monthly rhythms in tide heights. Enclosure experiments showed that bitidal foraging rhythms of iguanas may free run in the absence of direct cues from the intertidal areas and operate independent of the light:dark cycle and social stimuli. Therefore, the existence of a circatidal oscillator in marine iguanas is proposed. The bitidal foraging pattern may result from an interaction of a circadian system with a circatidal system. Food intake or related

  18. Rhythm generation through period concatenation in rat somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Mark A Kramer

    2008-09-01

    Full Text Available Rhythmic voltage oscillations resulting from the summed activity of neuronal populations occur in many nervous systems. Contemporary observations suggest that coexistent oscillations interact and, in time, may switch in dominance. We recently reported an example of these interactions recorded from in vitro preparations of rat somatosensory cortex. We found that following an initial interval of coexistent gamma ( approximately 25 ms period and beta2 ( approximately 40 ms period rhythms in the superficial and deep cortical layers, respectively, a transition to a synchronous beta1 ( approximately 65 ms period rhythm in all cortical layers occurred. We proposed that the switch to beta1 activity resulted from the novel mechanism of period concatenation of the faster rhythms: gamma period (25 ms+beta2 period (40 ms = beta1 period (65 ms. In this article, we investigate in greater detail the fundamental mechanisms of the beta1 rhythm. To do so we describe additional in vitro experiments that constrain a biologically realistic, yet simplified, computational model of the activity. We use the model to suggest that the dynamic building blocks (or motifs of the gamma and beta2 rhythms combine to produce a beta1 oscillation that exhibits cross-frequency interactions. Through the combined approach of in vitro experiments and mathematical modeling we isolate the specific components that promote or destroy each rhythm. We propose that mechanisms vital to establishing the beta1 oscillation include strengthened connections between a population of deep layer intrinsically bursting cells and a transition from antidromic to orthodromic spike generation in these cells. We conclude that neural activity in the superficial and deep cortical layers may temporally combine to generate a slower oscillation.

  19. Circadian Rhythm Connections to Oxidative Stress: Implications for Human Health

    Science.gov (United States)

    Wilking, Melissa; Ndiaye, Mary; Mukhtar, Hasan

    2013-01-01

    Abstract Significance: Oxygen and circadian rhythmicity are essential in a myriad of physiological processes to maintain homeostasis, from blood pressure and sleep/wake cycles, down to cellular signaling pathways that play critical roles in health and disease. If the human body or cells experience significant stress, their ability to regulate internal systems, including redox levels and circadian rhythms, may become impaired. At cellular as well as organismal levels, impairment in redox regulation and circadian rhythms may lead to a number of adverse effects, including the manifestation of a variety of diseases such as heart diseases, neurodegenerative conditions, and cancer. Recent Advances: Researchers have come to an understanding as to the basics of the circadian rhythm mechanism, as well as the importance of the numerous species of oxidative stress components. The effects of oxidative stress and dysregulated circadian rhythms have been a subject of intense investigations since they were first discovered, and recent investigations into the molecular mechanisms linking the two have started to elucidate the bases of their connection. Critical Issues: While much is known about the mechanics and importance of oxidative stress systems and circadian rhythms, the front where they interact has had very little research focused on it. This review discusses the idea that these two systems are together intricately involved in the healthy body, as well as in disease. Future Directions: We believe that for a more efficacious management of diseases that have both circadian rhythm and oxidative stress components in their pathogenesis, targeting both systems in tandem would be far more successful. Antioxid. Redox Signal. 19, 192–208 PMID:23198849

  20. A circadian rhythm of conidiation in Neurospora crassa (L-12)

    Science.gov (United States)

    Miyoshi, Yashuhiro

    1993-01-01

    Two fungi growth chambers containing six growth tubes each are used in this experiment. One chamber is for the space experiment; the other is for the simultaneous ground control experiment. The hyphae of Neurospora crassa band A mutant are inoculated at one end of each tube. Both the chambers are kept at 3 C plus or minus 1.5 C to stop hyphae growth until the Spacelab is activated. After the activation, each chamber is transferred simultaneously to the Spacelab and a phytotron in KSC and kept in continuous light at the same temperature. After about 24 hours of light exposure, each chamber is inserted into a growth chamber bag to keep it in constant darkness. The circadian rhythm of conidiation is initiated by this light to dark transition. After the dark incubation for 5 days at room temperature, both the growth chambers are kept at 3 C plus or minus 1.5 C to stop growth of the hyphae. After the space shuttle lands, both conidiation patterns are compared and analyzed. It has been known that numerous physiological phenomena show circadian rhythms. They are characterized by the fact that the oscillation can persist under constant conditions of light and temperature. Therefore, it has been accepted by most investigators that the generation mechanism of the circadian rhythm is endogeneous. However, one cannot reject the possibility that these rhythms are caused by some geophysical exogeneous factor having a 24-hour period, such as atmospheric pressure, gravity, or electromagnetic radiation. We use Neurospora crassa band A mutual which shows an obvious circadian rhythm in its spore-forming (conidiation) on the ground, and we intend to attempt the conidation of this mutant in the Spacelab where 24-hour periodicity is severely attenuated and to elucidate the effect of the geophysical exogeneous factor in the generation mechanism of the circadian rhythm.

  1. Kilometer-Spaced GNSS Array for Ionospheric Irregularity Monitoring

    Science.gov (United States)

    Su, Yang

    This dissertation presents automated, systematic data collection, processing, and analysis methods for studying the spatial-temporal properties of Global Navigation Satellite Systems (GNSS) scintillations produced by ionospheric irregularities at high latitudes using a closely spaced multi-receiver array deployed in the northern auroral zone. The main contributions include 1) automated scintillation monitoring, 2) estimation of drift and anisotropy of the irregularities, 3) error analysis of the drift estimates, and 4) multi-instrument study of the ionosphere. A radio wave propagating through the ionosphere, consisting of ionized plasma, may suffer from rapid signal amplitude and/or phase fluctuations known as scintillation. Caused by non-uniform structures in the ionosphere, intense scintillation can lead to GNSS navigation and high-frequency (HF) communication failures. With specialized GNSS receivers, scintillation can be studied to better understand the structure and dynamics of the ionospheric irregularities, which can be parameterized by altitude, drift motion, anisotropy of the shape, horizontal spatial extent and their time evolution. To study the structuring and motion of ionospheric irregularities at the sub-kilometer scale sizes that produce L-band scintillations, a closely-spaced GNSS array has been established in the auroral zone at Poker Flat Research Range, Alaska to investigate high latitude scintillation and irregularities. Routinely collecting low-rate scintillation statistics, the array database also provides 100 Hz power and phase data for each channel at L1/L2C frequency. In this work, a survey of seasonal and hourly dependence of L1 scintillation events over the course of a year is discussed. To efficiently and systematically study scintillation events, an automated low-rate scintillation detection routine is established and performed for each day by screening the phase scintillation index. The spaced-receiver technique is applied to cross

  2. Sleep quality and circadian rhythm disruption in the intensive care unit

    DEFF Research Database (Denmark)

    Boyko, Yuliya; Jennum, Poul; Toft, Palle

    2017-01-01

    , medication, as well as the critical illness itself have been reported as important sleep disturbing factors. Secretion of sleep hormone, melatonin, expressing circadian rhythmicity was found abolished or phase delayed in critically ill patients. Various interventions have been tested in several studies...... aiming to improve sleep quality and circadian rhythm in the ICU. The results of these studies were inconclusive due to using the sleep assessment methods other than PSG or the absence of a reliable sleep scoring tool for the analysis of the PSG findings in this patient population. Development of a valid...

  3. Effect of cataract surgery on regulation of circadian rhythms

    DEFF Research Database (Denmark)

    Erichsen, Jesper Høiberg; Brøndsted, Adam E; Kessel, Line

    2015-01-01

    was evaluated based on the principles described in the Grading of Recommendations Assessment, Development, and Evaluation system. A literature search of PubMed, Embase, and Cochrane Library databases was performed, as well as a search for unpublished trials at the U.S. National Institutes of Health Clinical...... Trials web site. Trials that reported the effect of cataract surgery on circadian rhythms were included. Outcomes were the Pittsburgh Sleep Quality Index (PSQI) global score, number of poor sleepers, Epworth Sleepiness Score, sleep efficiency, and mean concentration of melatonin. Cataract surgery...

  4. Circadian rhythm of temperature selection in a nocturnal lizard.

    Science.gov (United States)

    Refinetti, R; Susalka, S J

    1997-08-01

    We recorded body temperature and locomotor activity of Tokay geckos (Gekko gecko) with free access to a heat source under a 14:10 light-dark cycle and in constant darkness. Under the light-dark cycle, the lizards selected higher temperatures during the light phase, when locomotor activity was less intense. Rhythmicity in temperature selection was transiently disrupted but later resumed when the animals were placed in constant darkness. These results demonstrate the existence of a circadian rhythm of temperature selection in nocturnal ectotherms and extend previous findings of a temporal mismatch between the rhythms of locomotor activity and temperature selection in nocturnal rodents.

  5. Meditations on the unitary rhythm of dying-grieving.

    Science.gov (United States)

    Malinski, Violet M

    2012-07-01

    When someone faces loss of a loved one, that person simultaneously grieves and dies a little, just as the one dying also grieves. The author's personal conceptualization of dying and grieving as a unitary rhythm is explored based primarily on her interpretation of Rogers' science of unitary human beings, along with selected examples from related nursing literature and from the emerging focus on continuing bonds in other disciplines. Examples from contemporary songwriters that depict such a unitary conceptualization are given along with personal examples. The author concludes with her description of the unitary rhythm of dying-grieving.

  6. Rhythm-based segmentation of Popular Chinese Music

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    We present a new method to segment popular music based on rhythm. By computing a shortest path based on the self-similarity matrix calculated from a model of rhythm, segmenting boundaries are found along the di- agonal of the matrix. The cost of a new segment is opti- mized by matching manual...... and automatic segment boundaries. We compile a small song database of 21 randomly selected popular Chinese songs which come from Chinese Mainland, Taiwan and Hong Kong. The segmenting results on the small corpus show that 78% manual segmentation points are detected and 74% auto- matic segmentation points...

  7. Facial nerve activity disrupts psychomotor rhythms in the forehead microvasculature.

    Science.gov (United States)

    Drummond, Peter D; O'Brien, Geraldine

    2011-10-28

    Forehead blood flow was monitored in seven participants with a unilateral facial nerve lesion during relaxation, respiratory biofeedback and a sad documentary. Vascular waves at 0.1Hz strengthened during respiratory biofeedback, in tune with breathing cycles that also averaged 0.1Hz. In addition, a psychomotor rhythm at 0.15Hz was more prominent in vascular waveforms on the denervated than intact side of the forehead, both before and during relaxation and the sad documentary. These findings suggest that parasympathetic activity in the facial nerve interferes with the psychomotor rhythm in the forehead microvasculature. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Similarity estimators for irregular and age uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  9. Similarity estimators for irregular and age-uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  10. Ionospheric wave and irregularity measurements using passive radio astronomy techniques

    International Nuclear Information System (INIS)

    Erickson, W.C.; Mahoney, M.J.; Jacobson, A.R.; Knowles, S.H.

    1988-01-01

    The observation of midlatitude structures using passive radio astronomy techniques is discussed, with particular attention being given to the low-frequency radio telescope at the Clark Lake Radio Observatory. The present telescope operates in the 10-125-MHz frequency range. Observations of the ionosphere at separations of a few kilometers to a few hundreds of kilometers by the lines of sight to sources are possible, allowing the determination of the amplitude, wavelength, direction of propagation, and propagation speed of ionospheric waves. Data are considered on large-scale ionospheric gradients and the two-dimensional shapes and sizes of ionospheric irregularities. 10 references

  11. Analysis of an Irregular RC Multi-storeyed Building Subjected to Dynamic Loading

    Science.gov (United States)

    AkashRaut; Pachpor, Prabodh; Dautkhani, Sanket

    2018-03-01

    Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. So it is necessary to analyze the structure. The present paper is made to study three type of irregularity wiz vertical, mass and plan irregularity as per clause 7.1 of IS 1893 (part1)2002 code. The paper discusses the analysis of RC (Reinforced Concrete) Buildings with vertical irregularity. The study as a whole makes an effort to evaluate the effect of vertical irregularity on RC buildings for which comparison of three parameters namely shear force, bending moment and deflection are taken into account.

  12. Verification of a Method for Measuring Parkinson’s Disease Related Temporal Irregularity in Spiral Drawings

    Directory of Open Access Journals (Sweden)

    Somayeh Aghanavesi

    2017-10-01

    Full Text Available Parkinson’s disease (PD is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02. Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high

  13. Dim nighttime illumination interacts with parametric effects of bright light to increase the stability of circadian rhythm bifurcation in hamsters.

    Science.gov (United States)

    Evans, Jennifer A; Elliott, Jeffrey A; Gorman, Michael R

    2011-07-01

    The endogenous circadian pacemaker of mammals is synchronized to the environmental day by the ambient cycle of relative light and dark. The present studies assessed the actions of light in a novel circadian entrainment paradigm where activity rhythms are bifurcated following exposure to a 24-h light:dark:light:dark (LDLD) cycle. Bifurcated entrainment under LDLD reflects the temporal dissociation of component oscillators that comprise the circadian system and is facilitated when daily scotophases are dimly lit rather than completely dark. Although bifurcation can be stably maintained in LDLD, it is quickly reversed under constant conditions. Here the authors examine whether dim scotophase illumination acts to maintain bifurcated entrainment under LDLD through potential interactions with the parametric actions of bright light during the two daily photophases. In three experiments, wheel-running rhythms of Syrian hamsters were bifurcated under LDLD with dimly lit scotophases, and after several weeks, dim scotophase illumination was either retained or extinguished. Additionally, "full" and "skeleton" photophases were employed under LDLD cycles with dimly lit or completely dark scotophases to distinguish parametric from nonparametric effects of bright light. Rhythm bifurcation was more stable in full versus skeleton LDLD cycles. Dim light facilitated the maintenance of bifurcated entrainment under full LDLD cycles but did not prevent the loss of rhythm bifurcation in skeleton LDLD cycles. These studies indicate that parametric actions of bright light maintain the bifurcated entrainment state; that dim scotophase illumination increases the stability of the bifurcated state; and that dim light interacts with the parametric effects of bright light to increase the stability of rhythm bifurcation under full LDLD cycles. A further understanding of the novel actions of dim light may lead to new strategies for understanding, preventing, and treating chronobiological

  14. The Examination of Relationship between Life Rhythm and Parent's Consciousness among Young Children

    OpenAIRE

    Tanaka, Saori

    2008-01-01

    The social background of child care and rearing has changed rapidly today in Japan. Also young children's life rhythm has changed compared with before. These disorders of life rhythm cause big influence to young children's mind and body health. To improve young child's mind and body health, it is effective that parents improve the life rhythm at home. Therefore, the educational campaign to parents about young child's life rhythm was held. In this research, the relationship between improvement...

  15. The Biosynthetic Origin of Irregular Monoterpenes in Lavandula

    Science.gov (United States)

    Demissie, Zerihun A.; Erland, Lauren A. E.; Rheault, Mark R.; Mahmoud, Soheil S.

    2013-01-01

    Lavender essential oils are constituted predominantly of regular monoterpenes, for example linalool, 1,8-cineole, and camphor. However, they also contain irregular monoterpenes including lavandulol and lavandulyl acetate. Although the majority of genes responsible for the production of regular monoterpenes in lavenders are now known, enzymes (including lavandulyl diphosphate synthase (LPPS)) catalyzing the biosynthesis of irregular monoterpenes in these plants have not been described. Here, we report the isolation and functional characterization of a novel cis-prenyl diphosphate synthase cDNA, termed Lavandula x intermedia lavandulyl diphosphate synthase (LiLPPS), through a homology-based cloning strategy. The LiLPPS ORF, encoding for a 305-amino acid long protein, was expressed in Escherichia coli, and the recombinant protein was purified by nickel-nitrilotriacetic acid affinity chromatography. The approximately 34.5-kDa bacterially produced protein specifically catalyzed the head-to-middle condensation of two dimethylallyl diphosphate units to LPP in vitro with apparent Km and kcat values of 208 ± 12 μm and 0.1 s−1, respectively. LiLPPS is a homodimeric enzyme with a sigmoidal saturation curve and Hill coefficient of 2.7, suggesting a positive co-operative interaction among its catalytic sites. LiLPPS could be used to modulate the production of lavandulol and its derivatives in plants through metabolic engineering. PMID:23306202

  16. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-09-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archived MIPS observations of Phoebe reproduces Cassini results very accurately, thereby validating our method. For all targets, the geometric albedo is found to be low, probably below 10% and clearly below 15%. Irregular satellites are much darker than the large regular satellites. Their albedo is, however, quite similar to that of small bodies in the outer Solar System (such as cometary nuclei, Jupiter Trojans, or TNOs). This is consistent with color measurements as well as dynamical considerations which suggest a common origin of the said populations. There appear to be significant object-to-object albedo differences. Similar albedos found for some members of dynamical clusters support the idea that they may have originated in the breakup of a parent body. For three satellites, thermal data at two wavelengths are available, enabling us to constrain their thermal properties. Sub-solar temperatures are similar to that found from Cassini's Phoebe fly-by. This suggests a rather low thermal inertia, as expected for regolith-covered objects. This work is based on observations made with the Spitzer Space Telescope, which is operated by JPL under a contract with NASA. Support for this work was provided by NASA.

  17. Non-storm irregular variation of the Dst index

    Directory of Open Access Journals (Sweden)

    S. Nakano

    2012-01-01

    Full Text Available The Dst index has a long-term variation that is not associated with magnetic storms. We estimated the long-term non-storm component of the Dst variation by removing the short-term variation related to magnetic storms. The results indicate that the variation of the non-storm component includes not only a seasonal variation but also an irregular variation. The irregular long-term variation is likely to be due to an anti-correlation with the long-term variation of solar-wind activity. In particular, a clear anti-correlation is observed between the non-storm component of Dst and the long-term variation of the solar-wind dynamic pressure. This means that in the long term, the Dst index tends to increase when the solar-wind dynamic pressure decreases. We interpret this anti-correlation as an indication that the long-term non-storm variation of Dst is influenced by the tail current variation. The long-term variation of the solar-wind dynamic pressure controls the plasma sheet thermal pressure, and the change of the plasma sheet thermal pressure would cause the non-storm tail current variation, resulting in the non-storm variation of Dst.

  18. Model tracking dual stochastic controller design under irregular internal noises

    International Nuclear Information System (INIS)

    Lee, Jong Bok; Heo, Hoon; Cho, Yun Hyun; Ji, Tae Young

    2006-01-01

    Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and l/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation

  19. Using Radio Irregularity for Increasing Residential Energy Awareness

    Directory of Open Access Journals (Sweden)

    A. Miljković

    2012-06-01

    Full Text Available Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration.

  20. Colombia: la guerra irregular en el fin de siglo

    Directory of Open Access Journals (Sweden)

    Alfredo RANGEL SUÁREZ

    2009-11-01

    Full Text Available RESUMEN: El artículo analiza las transformaciones de la guerra irregular de las guerrillas colombianas en las últimas décadas. Para ello, se estudian los cambios que han afectado a distintos factores, como los objetivos estratégicos, los medios financieros, militares, las relaciones que mantienen con los partidos políticos tradicionales en el nivel local, sus parámetros ideológicos, el origen social de sus miembros. Con esta perspectiva, se analiza el cálculo político/temporal que la guerrilla hace en la actual coyuntura y sus consecuencias para el proceso de paz.ABSTRACT: This article examines the transformations of the irregular war of the colombian guerrillas, studying the changes of several factors such as the strategic goals, the financial and army resources, the relationship among the political parties in the local level, the evolution of their ideological parameters and of the social origin of their members. With this perspectiva, the author analyses temporal and political calculation that the guerrilla makes at this point, and its consequences for the peace process.

  1. Nonadiabatic two-electron transfer mediated by an irregular bridge

    International Nuclear Information System (INIS)

    Petrov, E.G.; Shevchenko, Ye.V.; May, V.

    2004-01-01

    Nonadiabatic two-electron transfer (TET) mediated by a linear molecular bridge is studied theoretically. Special attention is put on the case of a irregular distribution of bridge site energies as well as on the inter-site Coulomb interaction. Based on the unified description of electron transfer reactions [J. Chem. Phys. 115 (2001) 7107] a closed set of kinetic equations describing the TET process is derived. A reduction of this set to a single exponential donor-acceptor (D-A) TET is performed together with a derivation of an overall D-A TET rate. The latter contains a contribution of the stepwise as well as of the concerted route of D-A TET. The stepwise contribution is determined by two single-electron steps each of them associated with a sequential and a superexchange pathway. A two-electron unistep superexchange transition between the D and A forms the concerted contribution to the overall rate. Both contributions are analyzed in their dependency on the bridge length. The irregular distribution of the bridge site energies as well as the influence of the Coulomb interaction facilitates the D-A TET via a modification of the stepwise and the concerted part of the overall rate. At low temperatures and for short bridges with a single or two units the concerted contribution exceeds the stepwise contribution. If the bridge contains more than two units, the stepwise contribution dominates the overall rate

  2. Designing Next Generation Massively Multithreaded Architectures for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tumeo, Antonino; Secchi, Simone; Villa, Oreste

    2012-08-31

    Irregular applications, such as data mining or graph-based computations, show unpredictable memory/network access patterns and control structures. Massively multi-threaded architectures with large node count, like the Cray XMT, have been shown to address their requirements better than commodity clusters. In this paper we present the approaches that we are currently pursuing to design future generations of these architectures. First, we introduce the Cray XMT and compare it to other multithreaded architectures. We then propose an evolution of the architecture, integrating multiple cores per node and next generation network interconnect. We advocate the use of hardware support for remote memory reference aggregation to optimize network utilization. For this evaluation we developed a highly parallel, custom simulation infrastructure for multi-threaded systems. Our simulator executes unmodified XMT binaries with very large datasets, capturing effects due to contention and hot-spotting, while predicting execution times with greater than 90% accuracy. We also discuss the FPGA prototyping approach that we are employing to study efficient support for irregular applications in next generation manycore processors.

  3. Accuracy limits of the equivalent field method for irregular photon fields

    International Nuclear Information System (INIS)

    Sanz, Dario Esteban

    2002-01-01

    A mathematical approach is developed to evaluate the accuracy of the equivalent field method using basic clinical photon beam data. This paper presents an analytical calculation of dose errors arising when field equivalencies, calculated at a certain reference depth, are translated to other depths. The phantom scatter summation is expressed as a Riemann-Stieltjes integral and two categories of irregular fields are introduced: uniform and multiform. It is shown that multiform fields produce errors whose magnitudes are nearly twice those corresponding to uniform fields in extreme situations. For uniform field shapes, the maximum, local, relative dose errors, when the equivalencies are calculated at 10 cm depth on the central axis and translated to a depth of 30 cm, are 3.8% and 8.8% for 6 MV and cobalt-60 photon beams, respectively. In terms of maximum dose those errors are within 1-2%. This supports the conclusion that the equivalencies between rectangular fields, which are examples of uniform fields, are applicable to dose ratio functions irrespective of beam energy. However, the magnitude of such errors could be of importance when assessing the exit dose for in vivo monitoring. This work provides a better understanding of the influence of the irregular field shapes on the accuracy of the equivalent field method. (author)

  4. Application of Ground-Penetrating Radar for Detecting Internal Anomalies in Tree Trunks with Irregular Contours.

    Science.gov (United States)

    Li, Weilin; Wen, Jian; Xiao, Zhongliang; Xu, Shengxia

    2018-02-22

    To assess the health conditions of tree trunks, it is necessary to estimate the layers and anomalies of their internal structure. The main objective of this paper is to investigate the internal part of tree trunks considering their irregular contour. In this respect, we used ground penetrating radar (GPR) for non-invasive detection of defects and deteriorations in living trees trunks. The Hilbert transform algorithm and the reflection amplitudes were used to estimate the relative dielectric constant. The point cloud data technique was applied as well to extract the irregular contours of trunks. The feasibility and accuracy of the methods were examined through numerical simulations, laboratory and field measurements. The results demonstrated that the applied methodology allowed for accurate characterizations of the internal inhomogeneity. Furthermore, the point cloud technique resolved the trunk well by providing high-precision coordinate information. This study also demonstrated that cross-section tomography provided images with high resolution and accuracy. These integrated techniques thus proved to be promising for observing tree trunks and other cylindrical objects. The applied approaches offer a great promise for future 3D reconstruction of tomographic images with radar wave.

  5. The Rest-Activity Rhythm and Physical Activity in Early-Onset Dementia

    NARCIS (Netherlands)

    Hooghiemstra, A.M.; Eggermont, L.H.P.; Scheltens, P.; van der Flier, W.M.; Scherder, E.J.A.

    2015-01-01

    Background: A substantial part of elderly persons with dementia show rest-activity rhythm disturbances. The rest-activity rhythm is important to study in people with early-onset dementia (EOD) for rest-activity rhythm disturbances are predictive of institutionalization, and caregivers of young

  6. Sleep, 24-hour activity rhythms, and brain structure : A population-based study

    NARCIS (Netherlands)

    L.A. Zuurbier (Lisette)

    2016-01-01

    markdownabstractIn this thesis, Chapter 2 focuses on sleep, 24-hour activity rhythms and health. Chapter 2.1 describes the influence of demographics, lifestyle and sleep on 24-hour activity rhythms. In Chapter 2.2 sleep and 24-hour activity rhythms are used to predict mortality. This chapter is

  7. Circadian Sleep-Wake Rhythm of Older Adults with Intellectual Disabilities

    Science.gov (United States)

    Maaskant, Marijke; van de Wouw, Ellen; van Wijck, Ruud; Evenhuis, Heleen M.; Echteld, Michael A.

    2013-01-01

    The circadian sleep-wake rhythm changes with aging, resulting in a more fragmented sleep-wake pattern. In individuals with intellectual disabilities (ID), brain structures regulating the sleep-wake rhythm might be affected. The aims of this study were to compare the sleep-wake rhythm of older adults with ID to that of older adults in the general…

  8. Exogenous melatonin entrains rhythm and reduces amplitude of endogenous melatonin : An in vivo microdialysis study

    NARCIS (Netherlands)

    Drijfhout, W.J; Homan, E.J; Brons, H.F; Oakley, M; Skingle, M; Grol, Cor; Westerink, B.H.C.

    The circadian rhythm of melatonin production was studied using on-line, in vivo microdialysis in the rat pineal gland. With this technique it was possible to record a pronounced melatonin rhythm with very high time resolution. Three phase-markers of the rhythm were calculated from the data,

  9. Perceiving Speech Rhythm in Music: Listeners Classify Instrumental Songs According to Language of Origin

    Science.gov (United States)

    Hannon, Eric E.

    2009-01-01

    Recent evidence suggests that the musical rhythm of a particular culture may parallel the speech rhythm of that culture's language (Patel, A. D., & Daniele, J. R. (2003). "An empirical comparison of rhythm in language and music." "Cognition, 87," B35-B45). The present experiments aimed to determine whether listeners actually perceive such rhythmic…

  10. Rhythm Perception and Its Role in Perception and Learning of Dysrhythmic Speech

    Science.gov (United States)

    Borrie, Stephanie A.; Lansford, Kaitlin L.; Barrett, Tyson S.

    2017-01-01

    Purpose: The perception of rhythm cues plays an important role in recognizing spoken language, especially in adverse listening conditions. Indeed, this has been shown to hold true even when the rhythm cues themselves are dysrhythmic. This study investigates whether expertise in rhythm perception provides a processing advantage for perception…

  11. Speech rhythm in Kannada speaking adults who stutter.

    Science.gov (United States)

    Maruthy, Santosh; Venugopal, Sahana; Parakh, Priyanka

    2017-10-01

    A longstanding hypothesis about the underlying mechanisms of stuttering suggests that speech disfluencies may be associated with problems in timing and temporal patterning of speech events. Fifteen adults who do and do not stutter read five sentences, and from these, the vocalic and consonantal durations were measured. Using these, pairwise variability index (raw PVI for consonantal intervals and normalised PVI for vocalic intervals) and interval based rhythm metrics (PercV, DeltaC, DeltaV, VarcoC and VarcoV) were calculated for all the participants. Findings suggested higher mean values in adults who stutter when compared to adults who do not stutter for all the rhythm metrics except for VarcoV. Further, statistically significant difference between the two groups was found for all the rhythm metrics except for VarcoV. Combining the present results with consistent prior findings based on rhythm deficits in children and adults who stutter, there appears to be strong empirical support for the hypothesis that individuals who stutter may have deficits in generation of rhythmic speech patterns.

  12. Activity rhythms and distribution of natal dens for red foxes

    Science.gov (United States)

    Wenyang, Zhou; Wanhong, Wei; Biggins, Dean E.

    1995-01-01

    The red fox, Vulpes vulpes, was investigated with snow tracking, radiotracking and directive observation at the Haibei Research Station of Alpine Meadow Ecosystem, Academia Sinica, from March to September 1994. The objectives of this study were to determine the distribution and use of natal dens, activity rhythms, and home range sizes for the foxes.

  13. The importance of hormonal circadian rhythms in daily feeding patterns

    NARCIS (Netherlands)

    Boumans, Iris J.M.M.; Boer, de Imke J.M.; Hofstede, Gert Jan; Fleur, la Susanne E.; Bokkers, Eddy

    2017-01-01

    The interaction between hormonal circadian rhythms and feeding behaviour is not well understood. This study aimed to deepen our understanding of mechanisms underlying circadian feeding behaviour in animals, using pigs, Sus scrofa, as a case study. Pigs show an alternans feeding pattern, that is,

  14. Rhythm Perturbations in Acoustically Paced Treadmill Walking After Stroke

    NARCIS (Netherlands)

    Roerdink, M.; Lamoth, C.J.C.; van Kordelaar, J.; Elich, P.; Konijnenbelt, M.; Kwakkel, G.; Beek, P.J.

    2009-01-01

    Background. In rehabilitation, acoustic rhythms are often used to improve gait after stroke. Acoustic cueing may enhance gait coordination by creating a stable coupling between heel strikes and metronome beats and provide a means to train the adaptability of gait coordination to environmental

  15. Circadian rhythms in the hypothalamo-pituitary-adrenal (HPA) axis

    NARCIS (Netherlands)

    Kalsbeek, A.; van der Spek, R.; Lei, J.; Endert, E.; Buijs, R. M.; Fliers, E.

    2012-01-01

    The pronounced daily variation in the release of adrenal hormones has been at the heart of the deciphering and understanding of the circadian timing system. Indeed, the first demonstration of an endocrine day/night rhythm was provided by Pincus (1943), by showing a daily pattern of 17-keto-steroid

  16. EEG alpha rhythm, ocular activity and basal skin resistance

    NARCIS (Netherlands)

    Verbaten, M.N.; Beaujon, J.N.R.; Sjouw, W.

    Most hypotheses about the origin of the occipital alpha rhythm stress the specific influence of ocular activity. In this study, the influence of eye-movement frequency and extreme upward deviation of the eyeballs (enlarging the corneo-retinal potential) on occipital alpha activity and basal skin

  17. Ultradian rhythm unmasked in the Pdf clock mutant of Drosophila

    Indian Academy of Sciences (India)

    2014-07-20

    Ohtomo et al. .... stand the influence of these two phases, short sampling segments were ... per-long (perL) mutants also showed ultradian rhythms un- der L:L ..... would like to dedicate this paper to the memory of Dr Obaid. Siddiqi.

  18. Mood Disorders, Circadian Rhythms, Melatonin and Melatonin Agonists

    Directory of Open Access Journals (Sweden)

    M.A. Quera Salva

    2012-04-01

    Full Text Available Recent advances in the understanding of circadian rhythms have led to an interest in the treatment of major depressive disorder with chronobiotic agents. Many tissues have autonomous circadian rhythms, which are orchestrated by the master clock, situated in the suprachiasmatic nucleus (SNC. Melatonin (N-acetyl-5-hydroxytryptamine is secreted from the pineal gland during darkness. Melatonin acts mainly on MT1 and MT2 receptors, which are present in the SNC, regulating physiological and neuroendocrine functions, including circadian entrainment, referred to as the chronobiotic effet. Circadian rhythms has been shown to be either misaligned or phase shifted or decreased in amplitude in both acute episodes and relapse of major depressive disorder (MDD and bipolar disorder. Manipulation of circadian rhythms either using physical treatments (such as high intensity light or behavioral therapy has shown promise in improving symptoms. Pharmacotherapy using melatonin and pure melatonin receptor agonists, while improving sleep, has not been shown to improve symptoms of depression. A novel antidepressant, agomelatine, combines 5HT2c antagonist and melatonin agonist action, and has shown promise in both acute treatment of MDD and in preventing relapse.

  19. Discrepancy between circadian rhythms of inulin and creatinine clearance

    NARCIS (Netherlands)

    van Acker, B. A.; Koomen, G. C.; Koopman, M. G.; Krediet, R. T.; Arisz, L.

    1992-01-01

    To elucidate the disparity between circadian rhythmicity of inulin and creatinine clearance, we simultaneously measured inulin and creatinine clearances every 3 hours during 1 day in 14 normal subjects and in 8 patients with nephrotic syndrome. All patients and normal subjects had a circadian rhythm

  20. An analysis of rhythm in Japanese and English popular music

    NARCIS (Netherlands)

    Sadakata, M.; Desain, P.W.M.; Honing, H.J.; Patel, A.D.; Iversen, J.R.

    2003-01-01

    Recently, there has been evidence that the rhythm in English and French non-vocal musical themes are significantly different in their contrastiveness of successive durations in the same manner as those of spoken language, suggesting that acomposer's native language exerts an influence on the music

  1. Rapping dyslexia : learning rhythm, rhyme and flow in dyslectic children

    NARCIS (Netherlands)

    Tittarelli, M.; Marti, P.; Peppoloni, D.

    2014-01-01

    The paper presents a design case that draws inspiration from rap music as a way to tell stories rhythmically, with simple instruments for accompaniment. Rhythm, rhymes and flow are key features of rap music. In this study, we attempted to apply rap principles and dynamics to a very specific field of

  2. Circadian rhythms, metabolism, and chrononutrition in rodents and humans

    Science.gov (United States)

    Chrononutrition is an emerging discipline that builds on the intimate relation between endogenous circadian (24-h) rhythms and metabolism. Circadian regulation of metabolic function can be observed from the level of intracellular biochemistry to whole-organism physiology and even postprandial respon...

  3. Studies on circadian rhythm disturbances and melatonin in delirium

    NARCIS (Netherlands)

    de Jonghe, A.-M.

    2014-01-01

    The circadian sleep/wake rhythm disturbances that are seen in delirium and the role of melatonin supplementation provide a new angle in delirium research. More research is needed to determine the role of melatonin in the pathophysiological mechanisms of delirium and to determine whether the

  4. Transitions between beta and gamma rhythms in neural systems

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Setsinsky, D; Fausbøll, Anders

    2002-01-01

    We study the coexistence of different rhythms in a local network of one inhibitory and two excitatory nerve cells for a wide range of the excitatory synapse strength and of the slow K+-channel conductance. The dynamic features of spike trains in the presence of noise are discussed. It is found...

  5. Capturing daily urban rhythms: the use of location aware technologies

    CSIR Research Space (South Africa)

    Krygsman, S

    2007-07-01

    Full Text Available Daily activities and travel often follow a natural rhythm or flow that is structured by the fixed spatial and temporal constraints. The work and home location act as pegs that define individual’s activity space and it is within these spaces...

  6. Rhythm perturbations in acoustically paced treadmill walking after stroke.

    Science.gov (United States)

    Roerdink, Melvyn; Lamoth, Claudine J C; van Kordelaar, Joost; Elich, Peter; Konijnenbelt, Manin; Kwakkel, Gert; Beek, Peter J

    2009-09-01

    In rehabilitation, acoustic rhythms are often used to improve gait after stroke. Acoustic cueing may enhance gait coordination by creating a stable coupling between heel strikes and metronome beats and provide a means to train the adaptability of gait coordination to environmental changes, as required in everyday life ambulation. To examine the stability and adaptability of auditory-motor synchronization in acoustically paced treadmill walking in stroke patients. Eleven stroke patients and 10 healthy controls walked on a treadmill at preferred speed and cadence under no metronome, single-metronome (pacing only paretic or nonparetic steps), and double-metronome (pacing both footfalls) conditions. The stability of auditory-motor synchronization was quantified by the variability of the phase relation between footfalls and beats. In a separate session, the acoustic rhythms were perturbed and adaptations to restore auditory-motor synchronization were quantified. For both groups, auditory-motor synchronization was more stable for double-metronome than single-metronome conditions, with stroke patients exhibiting an overall weaker coupling of footfalls to metronome beats than controls. The recovery characteristics following rhythm perturbations corroborated the stability findings and further revealed that stroke patients had difficulty in accelerating their steps and instead preferred a slower-step response to restore synchronization. In gait rehabilitation practice, the use of acoustic rhythms may be more effective when both footfalls are paced. In addition, rhythm perturbations during acoustically paced treadmill walking may not only be employed to evaluate the stability of auditory-motor synchronization but also have promising implications for evaluation and training of gait adaptations in neurorehabilitation practice.

  7. [Circadian rhythm : Influence on Epworth Sleepiness Scale score].

    Science.gov (United States)

    Herzog, M; Bedorf, A; Rohrmeier, C; Kühnel, T; Herzog, B; Bremert, T; Plontke, S; Plößl, S

    2017-02-01

    The Epworth Sleepiness Scale (ESS) is frequently used to determine daytime sleepiness in patients with sleep-disordered breathing. It is still unclear whether different levels of alertness induced by the circadian rhythm influence ESS score. The aim of this study is to investigate the influence of circadian rhythm-dependent alertness on ESS performance. In a monocentric prospective noninterventional observation study, 97 patients with suspected sleep-disordered breathing were investigated with respect to daytime sleepiness in temporal relationship to polysomnographic examination and treatment. The Karolinska Sleepiness Scale (KSS) and the Stanford Sleepiness Scale (SSS) served as references for the detection of present sleepiness at three different measurement times (morning, noon, evening), prior to and following a diagnostic polysomnography night as well as after a continuous positive airway pressure (CPAP) titration night (9 measurements in total). The KSS, SSS, and ESS were performed at these times in a randomized order. The KSS and SSS scores revealed a circadian rhythm-dependent curve with increased sleepiness at noon and in the evening. Following a diagnostic polysomnography night, the scores were increased compared to the measurements prior to the night. After the CPAP titration night, sleepiness in the morning was reduced. KSS and SSS reflect the changes in alertness induced by the circadian rhythm. The ESS score war neither altered by the intra-daily nor by the inter-daily changes in the level of alertness. According to the present data, the ESS serves as a reliable instrument to detect the level of daytime sleepiness independently of the circadian rhythm-dependent level of alertness.

  8. Rhythm and timing in autism: Learning to dance

    Directory of Open Access Journals (Sweden)

    Pat eAmos

    2013-04-01

    Full Text Available In recent years, a significant body of research has focused on challenges to neural connectivity as a key to understanding autism. In contrast to attempts to identify a single static, primarily brain-based deficit, children and adults diagnosed with autism are increasingly perceived as out of sync with their internal and external environments in dynamic ways that must also involve operations of the peripheral nervous systems. The noisiness that seems to occur in both directions of neural flow may help explain challenges to movement and sensing, and ultimately to entrainment with circadian rhythms and social interactions. across the autism spectrum. Profound differences in the rhythm and timing of movement have been tracked to infancy. Difficulties with self-synchrony inhibit praxis, and can disrupt the dance of relationships through which caregiver and child build meaning. Different sensory aspects of a situation may fail to match up; ultimately, intentions and actions themselves may be uncoupled. This uncoupling may help explain the expressions of alienation from the actions of one’s body which recur in the autobiographical autism literature. Multi-modal/cross-modal coordination of different types of sensory information into coherent events may be difficult to achieve because amodal properties (e.g. rhythm and tempo that help unite perceptions are unreliable. One question posed to the connectivity research concerns the role of rhythm and timing in this operation, and whether these can be mobilized to reduce overload and enhance performance. A case is made for developmental research addressing how people with autism actively explore and make sense of their environments. The parent/author recommends investigating approaches such as scaffolding interactions via rhythm, following the person’s lead, slowing the pace, discriminating between intentional communication and stray motor patterns, and organizing information through one sensory mode at

  9. Circulating irisin in healthy, young individuals: day-night rhythm, effects of food intake and exercise, and associations with gender, physical activity, diet, and body composition.

    Science.gov (United States)

    Anastasilakis, Athanasios D; Polyzos, Stergios A; Saridakis, Zacharias G; Kynigopoulos, Georgios; Skouvaklidou, Elpida C; Molyvas, Dimitrios; Vasiloglou, Maria F; Apostolou, Aggeliki; Karagiozoglou-Lampoudi, Thomai; Siopi, Aikaterina; Mougios, Vassilis; Chatzistavridis, Panagiotis; Panagiotou, Grigorios; Filippaios, Andreas; Delaroudis, Sideris; Mantzoros, Christos S

    2014-09-01

    The myokine irisin may increase energy expenditure and affect metabolism. The objective of the study was to elucidate predictors of irisin and study whether circulating irisin may have day-night rhythm in humans. This was an observational, cross-sectional study with an additional 24-hour prospective observational arm (day-night rhythm substudy) and two prospective interventional arms (mixed meal substudy and exercise substudy). The study was conducted at the Hellenic Military School of Medicine (Thessaloniki, Greece). One hundred twenty-two healthy, young individuals were subjected to anthropometric and body composition measurements, and their eating and exercise behavior profiles were assessed with validated questionnaires. Subgroups were subjected to day-night rhythm, standardized meal ingestion, and 30-minute aerobic exercise studies. Circulating irisin levels were measured. Ιrisin levels were lower in males than females (P = .02) after adjustment for lean body mass, which was its major determinant. Irisin levels followed a day-night rhythm (P day-night rhythm, is correlated with lean body mass, and increases acutely after exercise.

  10. Got Rhythm...For Better and for Worse. Cross-Modal Effects of Auditory Rhythm on Visual Word Recognition

    Science.gov (United States)

    Brochard, Renaud; Tassin, Maxime; Zagar, Daniel

    2013-01-01

    The present research aimed to investigate whether, as previously observed with pictures, background auditory rhythm would also influence visual word recognition. In a lexical decision task, participants were presented with bisyllabic visual words, segmented into two successive groups of letters, while an irrelevant strongly metric auditory…

  11. The role of feeding rhythm, adrenal hormones and neuronal inputs in synchronizing daily clock gene rhythms in the liver

    NARCIS (Netherlands)

    Su, Yan; Cailotto, Cathy; Foppen, Ewout; Jansen, Remi; Zhang, Zhi; Buijs, Ruud; Fliers, Eric; Kalsbeek, Andries

    2016-01-01

    The master clock in the hypothalamic suprachiasmatic nucleus (SCN) is assumed to distribute rhythmic information to the periphery via neural, humoral and/or behavioral connections. Until now, feeding, corticosterone and neural inputs are considered important signals for synchronizing daily rhythms

  12. NO INFLUENCE OF HYPOXIA ON COORDINATION BETWEEN RESPIRATORY AND LOCOMOTOR RHYTHMS DURING ROWING AT MODERATE INTENSITY

    Directory of Open Access Journals (Sweden)

    Nicolas Fabre

    2007-12-01

    Full Text Available Besides neuro-mechanical constraints, chemical or metabolic stimuli have also been proposed to interfere with the coordination between respiratory and locomotor rhythms. In the light of the conflicting data observed in the literature, this study aimed to assess whether acute hypoxia modifies the degree of coordination between respiratory and locomotor rhythms during rowing exercises in order to investigate competitive interactions between neuro-mechanical (movement and chemical (hypoxia respiratory drives. Nine male healthy subjects performed one submaximal 6-min rowing exercise on a rowing ergometer in both normoxia (altitude: 304 m and acute hypoxia (altitude: 2877 m. The exercise intensity was about 40 % and 35 % (for normoxia and hypoxia conditions, respectively of the individual maximal power output measured during an incremental rowing test to volitional exhaustion carried out in normoxia. Metabolic rate and minute ventilation were continuously collected throughout exercise. Locomotor movement and breathing rhythms were continuously recorded and synchronized cycle-by-cycle. The degree of coordination was expressed as a percentage of breaths starting during the same phase of the locomotor cycle. For a same and a constant metabolic rate, acute hypoxia did not influence significantly the degree of coordination (mean ± SEM, normoxia: 20.0 ± 6.2 %, hypoxia: 21.3 ± 11.1 %, p > 0.05 while ventilation and breathing frequency were significantly greater in hypoxia. Our results may suggest that during rowing exercise at a moderate metabolic load, neuro-mechanical locomotion-linked respiratory stimuli appear "stronger" than peripheral chemoreceptors- linked respiratory stimuli induced by hypoxia, in the context of our study

  13. Multifractal Detrended Fluctuation Analysis of alpha and theta EEG rhythms with musical stimuli

    International Nuclear Information System (INIS)

    Maity, Akash Kumar; Pratihar, Ruchira; Mitra, Anubrato; Dey, Subham; Agrawal, Vishal; Sanyal, Shankha; Banerjee, Archi; Sengupta, Ranjan; Ghosh, Dipak

    2015-01-01

    Highlights: • EEG was done to record the brain electrical activity of 10 subjects in response to simple acoustical tanpura stimuli. • Empirical Mode Decomposition (EMD) technique used to make the EEG signal free from blink and other muscular artifacts. • Multifractal Detrended Fluctuation Analysis (MFDFA) performed to assess the complexity of extracted alpha and theta brain rhythms. • The findings show spectral width i.e. complexity of alpha and theta rhythms increase in all the seven frontal locations studied, under the effect of musical stimuli. - Abstract: Electroencephalography (EEG) was performed on 10 participants using a simple acoustical stimuli i.e. a tanpura drone. The tanpura drone is free from any semantic content and is used with a hypothesis that it provides a specific resting environment for the listeners. The EEG data was extracted for all the frontal electrodes viz. F3, F4, F7, F8, Fp1, Fp2 and Fz. Empirical Mode Decomposition (EMD) was applied on the acquired raw EEG signal to make it free from blink as well as other muscular artifacts. Wavelet Transform (WT) technique was used to segregate alpha and theta waves from the denoised EEG signal. Non-linear analysis in the form of Multifractal Detrended Fluctuation Analysis (MFDFA) was carried out on the extracted alpha and theta time series data to study the variation of their complexity. It was found that in all the frontal electrodes alpha as well as theta complexity increases as is evident from the increase of multifractal spectral width. This study is entirely new and gives interesting data regarding neural activation of the alpha and theta brain rhythms while listening to simple acoustical stimuli. The importance of this study lies in the context of emotion quantification using multifractal spectral width as a parameter as well as in the field of cognitive music therapy. The results are discussed in detail.

  14. The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash; Safi, Sanam; Nielsen, Emil E

    2017-01-01

    by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of any rhythm control strategy versus any rate control strategy. We plan to search the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, Science Citation Index Expanded...... on Web of Science, and BIOSIS to identify relevant trials. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5....... This protocol for a systematic review aims at identifying the best overall treatment strategy for atrial fibrillation and atrial flutter. METHODS: This protocol for a systematic review was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested...

  15. The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash J; Feinberg, Joshua; Nielsen, Emil E

    2017-01-01

    -effect meta-analysis and chose the most conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. Statistical heterogeneity was assessed by visual inspection of forest plots and by calculating inconsistency (I2) for traditional meta-analyses and diversity...... (D2) for TSA. Sensitivity analyses and subgroup analyses were conducted to explore the reasons for substantial statistical heterogeneity. We assessed the risk of publication bias in meta-analyses consisting of 10 trials or more with tests for funnel plot asymmetry. We used GRADE to assess the quality...... of the body of evidence. RESULTS: 25 randomized clinical trials (n = 9354 participants) were included, all of which were at high risk of bias. Meta-analysis showed that rhythm control strategies versus rate control strategies significantly increased the risk of a serious adverse event (risk ratio (RR), 1...

  16. Massive stars in the Sagittarius Dwarf Irregular Galaxy

    Science.gov (United States)

    Garcia, Miriam

    2018-02-01

    Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescopes. This Letter presents low-resolution spectroscopy executed with the Gran Telescopio Canarias that confirms that SagDIG hosts massive stars. The observations unveiled three OBA-type stars and one red supergiant candidate. Pending confirmation from high-resolution follow-up studies, these could be the most metal-poor massive stars of the Local Group.

  17. Evaluation of Surface Slope Irregularity in Linear Parabolic Solar Collectors

    Directory of Open Access Journals (Sweden)

    F. Francini

    2012-01-01

    Full Text Available The paper describes a methodology, very simple in its application, for measuring surface irregularities of linear parabolic collectors. This technique was principally developed to be applied in cases where it is difficult to use cumbersome instruments and to facilitate logistic management. The instruments to be employed are a digital camera and a grating. If the reflector surface is defective, the image of the grating, reflected on the solar collector, appears distorted. Analyzing the reflected image, we can obtain the local slope of the defective surface. These profilometric tests are useful to identify and monitor the mirror portions under mechanical stress and to estimate the losses caused by the light rays deflected outside the absorber.

  18. Constructing a logical, regular axis topology from an irregular topology

    Science.gov (United States)

    Faraj, Daniel A.

    2014-07-01

    Constructing a logical regular topology from an irregular topology including, for each axial dimension and recursively, for each compute node in a subcommunicator until returning to a first node: adding to a logical line of the axial dimension a neighbor specified in a nearest neighbor list; calling the added compute node; determining, by the called node, whether any neighbor in the node's nearest neighbor list is available to add to the logical line; if a neighbor in the called compute node's nearest neighbor list is available to add to the logical line, adding, by the called compute node to the logical line, any neighbor in the called compute node's nearest neighbor list for the axial dimension not already added to the logical line; and, if no neighbor in the called compute node's nearest neighbor list is available to add to the logical line, returning to the calling compute node.

  19. Irregularities of ionospheric VTEC during lightning activity over Antarctic Peninsula

    International Nuclear Information System (INIS)

    Suparta, W; Wan Mohd Nor, W N A

    2017-01-01

    This paper investigates the irregularities of vertical total electron content (VTEC) during lightning activity and geomagnetic quiet days over Antarctic Peninsula in year 2014. During the lightning event, the ionosphere may be disturbed which may cause disruption in the radio signal. Thus, it is important to understand the influence of lightning on VTEC in the study of upper-lower interaction. The lightning data is obtained from World Wide Lightning Location Network (WWLLN) and the VTEC data has analyzed from Global Positioning System (GPS) for O’Higgins (OHI3), Palmer (PALV), and Rothera (ROTH). The results demonstrate the VTEC variation of ∼0.2 TECU during low lightning activity which could be caused by energy dissipation through lightning discharges from troposphere into the thermosphere. (paper)

  20. Global scale ionospheric irregularities associated with thunderstorm activity

    International Nuclear Information System (INIS)

    Pulinets, Sergey A.; Depuev, Victor H.

    2003-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstorm electric fields onto the Earth's ionosphere. (author)

  1. Global scale ionospheric irregularities associated with thunderstorm activity

    CERN Document Server

    Pulinets, S A

    2002-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstor...

  2. Asymmetry and irregularity border as discrimination factor between melanocytic lesions

    Science.gov (United States)

    Sbrissa, David; Pratavieira, Sebastião.; Salvio, Ana Gabriela; Kurachi, Cristina; Bagnato, Vanderlei Salvadori; Costa, Luciano Da Fontoura; Travieso, Gonzalo

    2015-06-01

    Image processing tools have been widely used in systems supporting medical diagnosis. The use of mobile devices for the diagnosis of melanoma can assist doctors and improve their diagnosis of a melanocytic lesion. This study proposes a method of image analysis for melanoma discrimination from other types of melanocytic lesions, such as regular and atypical nevi. The process is based on extracting features related with asymmetry and border irregularity. It were collected 104 images, from medical database of two years. The images were obtained with standard digital cameras without lighting and scale control. Metrics relating to the characteristics of shape, asymmetry and curvature of the contour were extracted from segmented images. Linear Discriminant Analysis was performed for dimensionality reduction and data visualization. Segmentation results showed good efficiency in the process, with approximately 88:5% accuracy. Validation results presents sensibility and specificity 85% and 70% for melanoma detection, respectively.

  3. Manufacturing of Cast Metal Foams with Irregular Cell Structure

    Directory of Open Access Journals (Sweden)

    Kroupová I.

    2015-06-01

    Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

  4. Method for hot pressing irregularly shaped refractory articles

    Science.gov (United States)

    Steinkamp, William E.; Ballard, Ambrose H.

    1982-01-01

    The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

  5. Irregular Migration - between legal status and social practices

    DEFF Research Database (Denmark)

    Lund Thomsen, Trine

    2012-01-01

    Arnfinn H. and Rogstad, Jon 2.Book reviews by null 3.INVISIBLE IMMIGRANTS, VISIBLE EXPATS? Americans in Finnish discourses on immigration and internationalization by Leinonen, Johanna 4.Migrants in the Scandinavian Welfare State by Brochmann, Grete and Hagelund, Anniken 5.TOWARD AN IDENTITY STRESS....... Language and religious affiliations of an immigrant adolescent in Norway by Haque, Shahzaman View Top 20 Most Downloaded Articles Previous Article Next Article Go to table of contents Download full text pdf (PDF, 425 KB) Irregular Migration – Between Legal Status and Social Practices Narratives of Polish...... connected to the specific area of activity and to the accumulated capital of the individual. The aim is to identify how opportunity structures affect the migration process and how migrants react to them depending on the available capital and biographical knowledge and experiences. The horizon of experience...

  6. New Computational Approach to Electron Transport in Irregular Graphene Nanostructures

    Science.gov (United States)

    Mason, Douglas; Heller, Eric; Prendergast, David; Neaton, Jeffrey

    2009-03-01

    For novel graphene devices of nanoscale-to-macroscopic scale, many aspects of their transport properties are not easily understood due to difficulties in fabricating devices with regular edges. Here we develop a framework to efficiently calculate and potentially screen electronic transport properties of arbitrary nanoscale graphene device structures. A generalization of the established recursive Green's function method is presented, providing access to arbitrary device and lead geometries with substantial computer-time savings. Using single-orbital nearest-neighbor tight-binding models and the Green's function-Landauer scattering formalism, we will explore the transmission function of irregular two-dimensional graphene-based nanostructures with arbitrary lead orientation. Prepared by LBNL under contract DE-AC02-05CH11231 and supported by the U.S. Dept. of Energy Computer Science Graduate Fellowship under grant DE-FG02-97ER25308.

  7. Kriging for interpolation of sparse and irregularly distributed geologic data

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K.

    1986-12-31

    For many geologic problems, subsurface observations are available only from a small number of irregularly distributed locations, for example from a handful of drill holes in the region of interest. These observations will be interpolated one way or another, for example by hand-drawn stratigraphic cross-sections, by trend-fitting techniques, or by simple averaging which ignores spatial correlation. In this paper we consider an interpolation technique for such situations which provides, in addition to point estimates, the error estimates which are lacking from other ad hoc methods. The proposed estimator is like a kriging estimator in form, but because direct estimation of the spatial covariance function is not possible the parameters of the estimator are selected by cross-validation. Its use in estimating subsurface stratigraphy at a candidate site for geologic waste repository provides an example.

  8. Towards intrinsic magnetism of graphene sheets with irregular zigzag edges.

    Science.gov (United States)

    Chen, Lianlian; Guo, Liwei; Li, Zhilin; Zhang, Han; Lin, Jingjing; Huang, Jiao; Jin, Shifeng; Chen, Xiaolong

    2013-01-01

    The magnetism of graphene has remained divergent and controversial due to absence of reliable experimental results. Here we show the intrinsic magnetism of graphene edge states revealed based on unidirectional aligned graphene sheets derived from completely carbonized SiC crystals. It is found that ferromagnetism, antiferromagnetism and diamagnetism along with a probable superconductivity exist in the graphene with irregular zigzag edges. A phase diagram is constructed to show the evolution of the magnetism. The ferromagnetic ordering curie-temperature of the fundamental magnetic order unit (FMOU) is 820 ± 80 K. The antiferromagnetic ordering Neel temperature of the FMOUs belonging to different sublattices is about 54 ± 2 K. The diamagnetism is similar to that of graphite and can be well described by the Kotosonov's equation. Our experimental results provide new evidences to clarify the controversial experimental phenomena observed in graphene and contribute to a deeper insight into the nature of magnetism in graphene based system.

  9. Combined radar observations of equatorial electrojet irregularities at Jicamarca

    Directory of Open Access Journals (Sweden)

    D. L. Hysell

    2007-03-01

    Full Text Available Daytime equatorial electrojet plasma irregularities were investigated using five distinct radar diagnostics at Jicamarca including range-time-intensity (RTI mapping, Faraday rotation, radar imaging, oblique scattering, and multiple-frequency scattering using the new AMISR prototype UHF radar. Data suggest the existence of plasma density striations separated by 3–5 km and propagating slowly downward. The striations may be caused by neutral atmospheric turbulence, and a possible scenario for their formation is discussed. The Doppler shifts of type 1 echoes observed at VHF and UHF frequencies are compared and interpreted in light of a model of Farley Buneman waves based on kinetic ions and fluid electrons with thermal effects included. Finally, the up-down and east-west asymmetries evident in the radar observations are described and quantified.

  10. Comparison of different dose calculation methods for irregular photon fields

    International Nuclear Information System (INIS)

    Zakaria, G.A.; Schuette, W.

    2000-01-01

    In this work, 4 calculation methods (Wrede method, Clarskon method of sector integration, beam-zone method of Quast and pencil-beam method of Ahnesjoe) are introduced to calculate point doses in different irregular photon fields. The calculations cover a typical mantle field, an inverted Y-field and different blocked fields for 4 and 10 MV photon energies. The results are compared to those of measurements in a water phantom. The Clarkson and the pencil-beam method have been proved to be the methods of equal standard in relation to accuracy. Both of these methods are being distinguished by minimum deviations and applied in our clinical routine work. The Wrede and beam-zone methods deliver useful results to central beam and yet provide larger deviations in calculating points beyond the central axis. (orig.) [de

  11. Experimental Study of Irregular Waves on a Gravel Beach

    Science.gov (United States)

    Hu, Nai-Ren; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

    2017-04-01

    In the east coast of Taiwan, the sort grain size more belongs to cobble or gravel, which is physically distinct compared to the sandy beach in the west coast of Taiwan. Although gravel beaches can dissipate more of wave energy, gravel beaches were eroded and coastal road were damaged especially during typhoons. The purpose of this study is to investigate the geomorphological response of gravel beach due to irregular waves. This experiment was carry out in a 21m long, 50 cm wide, 70 cm high wave tank at Tainan Hydraulics Laboratory, National Cheng-Kung University, Taiwan. To simulate of the geometry in the east coast of Taiwan, a physical model with 1/36 scale-down was used, in which the seawall was 10cm built upon a 1:10 slope and gravel grains with D50 being 3.87 mm was nourished in front of the seawall. In terms of typhoon-scale wave condition, irregular waves with scale-down conditions were generated for 600 s for each scenarios and, three different water levels with respect to the gravel beach are designed. Application of laser combined with image processing to produce 3D topographic map, the erosion zone and accretion zone would be found. The resulting morphological change of gravel beach will be measured using an integrated laser and image processing tool to have 3D topographic maps. It is expected to have more understanding about under what conditions the gravel coasts suffer the least damage. In particular, the relation between erosion rates of gravel beach, the angle of gravel slope and the length of the plane on the gravel slope will be achieved

  12. Tamoxifen treatment of bleeding irregularities associated with Norplant use.

    Science.gov (United States)

    Abdel-Aleem, Hany; Shaaban, Omar M; Amin, Ahmed F; Abdel-Aleem, Aly M

    2005-12-01

    To evaluate the possible role of tamoxifen (selective estrogen receptor modulators, SERM) in treating bleeding irregularities associated with Norplant contraceptive use. Randomized clinical trial including 100 Norplant users complaining of vaginal bleeding irregularities. The trial was conducted in the Family Planning Clinic of Assiut University Hospital. Women were assigned at random to receive tamoxifen tablets (10 mg) twice daily for 10 days or similar placebo. Women were followed-up for 3 months. The end points were percentage of women who stopped bleeding during treatment, bleeding/spotting days during the period of follow-up, effect of treatment on their lifestyle, and side effects and discontinuation of contraception. There was good compliance with treatment. At the end of treatment, a significantly higher percentage of tamoxifen users stopped bleeding in comparison to the control group (88% vs. 68%, respectively; p=.016). Women who used tamoxifen had significantly less bleeding and/or spotting days than women who used placebo, during the first and second months. During the third month, there were no significant differences between the two groups. Women who used tamoxifen reported improvement in performing household activities, religious duties and in sexual life, during the first 2 months. In the third month, there were no differences between the two groups. There were no significant differences between tamoxifen and placebo groups in reporting side effects. In the group who used tamoxifen, two women discontinued Norplant use because of bleeding vs. nine women in the placebo group. Tamoxifen use at a dose of 10 mg twice daily orally, for 10 days, has a beneficial effect on vaginal bleeding associated with Norplant use. In addition, the bleeding pattern was better in women who used tamoxifen for the following 2 months after treatment. However, these results have to be confirmed in a larger trial before advocating this line of treatment.

  13. ESA' s novel gravitational modeling of irregular planetary bodies

    Science.gov (United States)

    Ortega, Guillermo

    A detailed understanding and modeling of the gravitational modeling is required for realistic investigation of the dynamics of orbits close to irregularly shaped bodies. Gravity field modelling up to a certain maximum spherical harmonic degree N involves N2 unkown spherical harmonic coefficients or complex harmonics. The corresponding number of matrix entries reaches till N4 . For missions like CHAMP, GRACE or GOCE, the maximum degree of resolution is 75, 150 and 300 respectively. Therefore, the number of unknowns for a satellite like GOCE will be around 100.000. Since these missions usually fly for a period of time of several years, the number of observations is huge. Hence, gravity field recovery from these missions is a high demanding task. The classical approaches like spherical expansion of the potential lead generally to a high number of coefficients, which reduce the software computational efficiency of the orbit propagation and which have mostly a limited physical meaning. One of the main targets of the activity is the modelling of asteroids, small moons, and cometary bodies. All celestial bodies are irregular by definition. However, the scope of the activity is broad enough as to be able to use the models and the software in quasy-regular bodies as well. Therefore the models and tools could be used for bodies such as the Moon, Mars, Venus, Deimos, Europa, Eros, Mathilda, and Churyumov-Gerasimenko, etc., being these applications relevant for scientific (Rosetta, Bepi Colombo), exploration (Exo-Mars), NEO mitigation (Don Quijote) and Earth observation (GOCE) missions of ESA.

  14. Volume determination of irregularly-shaped quasi-spherical nanoparticles.

    Science.gov (United States)

    Attota, Ravi Kiran; Liu, Eileen Cherry

    2016-11-01

    Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to determine the volume of regular NPs such as spheres and cubes from a one-dimensional or two-dimensional measurement. However, due to the three-dimensional nature of NPs, it is challenging to determine the proper physical size of many types of regularly and irregularly-shaped quasi-spherical NPs at high-throughput using a single tool. Here, we present a relatively simple method that determines a better volume estimate of NPs by combining measurements from their top-down projection areas and peak heights using two tools. The proposed method is significantly faster and more economical than the electron tomography method. We demonstrate the improved accuracy of the combined method over scanning electron microscopy (SEM) or atomic force microscopy (AFM) alone by using modeling, simulations, and measurements. This study also exposes the existence of inherent measurement biases for both SEM and AFM, which usually produce larger measured diameters with SEM than with AFM. However, in some cases SEM measured diameters appear to have less error compared to AFM measured diameters, especially for widely used IS-NPs such as of gold, and silver. The method provides a much needed, proper high-throughput volumetric measurement method useful for many applications. Graphical Abstract The combined method for volume determination of irregularly-shaped quasi-spherical nanoparticles.

  15. Reproducibility of irregular radiation fields for malignant lymphoma

    International Nuclear Information System (INIS)

    Mock, U.; Dieckmann, K.; Poetter, R.; Molitor, A.M.; Haverkamp, U.

    1998-01-01

    Purpose: Radiation treatment for malignant lymphoma requires large field irradiation with irregular blocks according to the individual anatomy and tumor configuration. For determination of safety margins (PTV) we quantitatively analysed the accuracy of field and block placement with regard to different anatomical regions. Patients and Methods: Forty patients with malignant lymphoma were irradiated using the classical supra-/infradiaphragmatic field arrangements. Treatment was performed with 10-MeV photons and irregularly shaped, large opposing fields. We evaluated the accuracy of field and block placements during the treatment courses by comparing the regularly performed verification - with the simulation films. Deviations were determined with respect to the field edges and the central axis, along the x- and z-axis. Results: With regard to the field edges, mean deviations of 2.0 mm and 3.4 mm were found along the x- and z-axis. The corresponding standard deviations were 3.4 mm and 5.5 mm, respectively. With regard to the shielding blocks, mean displacement along the x- and z-axis was 2.2 mm and 3.8 mm. In addition, overall standard deviations of 5.7 mm (x-axis) and 7.1 mm (z-axis) were determined. During the course of time an improved accuracy of block placement was notable. Conclusion: Systematic analysis of port films gives information for a better defining safety margins in external radiotherapy. Evaluation of verification films on a regular basis improves set-up accuracy by reducing displacements. (orig.) [de

  16. THE VALUE OF CLASS-IC ANTIARRHYTHMIC DRUGS FOR ACUTE CONVERSION OF PAROXYSMAL ATRIAL-FIBRILLATION OR FLUTTER TO SINUS RHYTHM

    NARCIS (Netherlands)

    SUTTORP, MJ; KINGMA, JH; JESSURUN, ER; LIEAHUEN, L; VANHEMEL, NM; LIE, KI

    1990-01-01

    In a single-blind randomized study, the efficacy and safety of intravenous propafenone (2 mg/kg body weight per 10 min) versus flecainide (2 mg/kg per 10 min) were assessed in 50 patients with atrial fibrillation or flutter. Treatment was considered successful if sinus rhythm occurred within 1 h.

  17. Mother-infant circadian rhythm: development of individual patterns and dyadic synchrony.

    Science.gov (United States)

    Thomas, Karen A; Burr, Robert L; Spieker, Susan; Lee, Jungeun; Chen, Jessica

    2014-12-01

    Mutual circadian rhythm is an early and essential component in the development of maternal-infant physiological synchrony. The aim of this to examine the longitudinal pattern of maternal-infant circadian rhythm and rhythm synchrony as measured by rhythm parameters. In-home dyadic actigraphy monitoring at infant age 4, 8, and 12 weeks. Forty-three healthy mother-infant pairs. Circadian parameters derived from cosinor and non-parametric analysis including mesor, magnitude, acrophase, L5 and M10 midpoints (midpoint of lowest 5 and highest 10h of activity), amplitude, interdaily stability (IS), and intradaily variability (IV). Mothers experienced early disruption of circadian rhythm, with re-establishment of rhythm over time. Significant time effects were noted in increasing maternal magnitude, amplitude, and IS and decreasing IV (pcircadian pattern with significant time effects for increasing mesor, magnitude, amplitude, L5, IS, and IV (pcircadian rhythm. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Measurements of electron density irregularities in the ionosphere of Jupiter by Pioneer 10

    International Nuclear Information System (INIS)

    Woo, R.; Yang, F.

    1976-01-01

    In this paper we demonstrate that when the frequency spectrum of the log amplitude fluctuations is used, the radio occultation experiment is a powerful tool for detecting, identifying, and studying ionospheric irregularities. Analysis of the Pioneer 10 radio occultation measurements reveals that the Jovian ionosphere possesses electron density irregularities which are very similar to those found in the earth's ionosphere. This is the first time such irregularities have been found in a planetary ionosphere other than that of earth. The Pioneer 10 results indicate that the spatial wave number spectrum of the electron density irregularities is close to the Kolmogorov spectrum and that the outer scale size is greater than the Fresnel size (6.15 km). This type of spectrum suggests that the irregularities are probably produced by the turbulent dissipation of irregularities larger than the outer scale size

  19. Top-down regulation of left temporal cortex by hypnotic amusia for rhythm: a pilot study on mismatch negativity.

    Science.gov (United States)

    Facco, Enrico; Ermani, Mario; Rampazzo, Patrizia; Tikhonoff, Valérie; Saladini, Marina; Zanette, Gastone; Casiglia, Edoardo; Spiegel, David

    2014-01-01

    To evaluate the effect of hypnotically induced amusia for rhythm (a condition in which individuals are unable to recognize melodies or rhythms) on mismatch negativity (MMN), 5 highly (HH) and 5 poorly (LH) hypnotizable nonmusician volunteers underwent MMN recording before and during a hypnotic suggestion for amusia. MMN amplitude was recorded using a 19-channel montage and then processed using the low-resolution electromagnetic tomography (LORETA) to localize its sources. MMN amplitude was significantly decreased during hypnotic amusia (p < .04) only in HH, where the LORETA maps of MMN showed a decreased source amplitude in the left temporal lobe, suggesting a hypnotic top-down regulation of activity of these areas and that these changes can be assessed by neurophysiological investigations.

  20. Crime among irregular immigrants and the influence of internal border control

    OpenAIRE

    Leerkes, Arjen; Engbersen, Godfried; Leun, Joanne

    2012-01-01

    textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants from the formal labour market and public provisions. At the same time the registered crime among irregular migrants rose. The 'marginalisation thesis' asserts that a larger number of migrants hav...

  1. Effects of magnetic storm phases on F layer irregularities below the auroral oval

    International Nuclear Information System (INIS)

    Aarons, J.; Gurgiolo, C.; Rodger, A.S.

    1988-01-01

    Observations of F-layer irregularity development and intensity were obtained between September and October 1981, primarily over subauroral latitudes in the area of the plasmapause. The results reveal the descent of the auroral irregularity region to include subauroral latitudes in the general area of the plasmapause during the main phases of a series of magnetic storms. Irregularities were found primarily at lower latitudes during the subauroral or plasmapause storm. A model for the subauroral irregularities in recovery phases of magnetic storms is proposed in which energy stored in the ring current is slowly released. 27 references

  2. Dependence on zenith angle of the strength of 3-meter equatorial electrojet irregularities

    International Nuclear Information System (INIS)

    Ierkic, H.M.; Fejer, B.G.; Farley, D.T.

    1980-01-01

    Radar measurements in Peru were used to deduce the zenith angle dependence of the scattering cross section of plasma irregularities generated by instabilities in the equatorial electrojet. The irregularities probed by the 50 MHz Jicamarca radar had a wavelength of 3m. The cross section for the type 2 irregularities was isotopic in the plane perpendicular to the magnetic field, while the cross section for the stronger type 1 irregularities varied with zenith angle at a rate of approximately 0.3 dB/degree; the horizontally traveling waves were more than 100 times stronger than those traveling vertically

  3. Spatial irregularities in Jupiter's upper ionosphere observed by Voyager radio occultations

    Science.gov (United States)

    Hinson, D. P.; Tyler, G. L.

    1982-01-01

    Radio scintillations (at 3.6 and 13 cm) produced by scattering from ionospheric irregularities during the Voyager occultations are interpreted using a weak-scattering theory. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yield estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. It is shown that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

  4. Musical genres: beating to the rhythms of different drums

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Debora C; Costa, Luciano da F [Instituto de Fisica de Sao Carlos - Universidade de Sao Paulo, Av. Trabalhador Sao Carlense 400, Caixa Postal 369, CEP 13560-970, Sao Carlos, Sao Paulo (Brazil); Saito, Jose H, E-mail: deboracorrea@ursa.ifsc.usp.b, E-mail: luciano@ursa.ifsc.usp.b [Departamento de Computacao-Universidade Federal de Sao Carlos, Rodovia Washington Luis, km 235, SP-310, CEP 13565-905, Sao Carlos, Sao Paulo (Brazil)

    2010-05-15

    Online music databases have increased significantly as a consequence of the rapid growth of the Internet and digital audio, requiring the development of faster and more efficient tools for music content analysis. Musical genres are widely used to organize music collections. In this paper, the problem of automatic single and multi-label music genre classification is addressed by exploring rhythm-based features obtained from a respective complex network representation. A Markov model is built in order to analyse the temporal sequence of rhythmic notation events. Feature analysis is performed by using two multivariate statistical approaches: principal components analysis (unsupervised) and linear discriminant analysis (supervised). Similarly, two classifiers are applied in order to identify the category of rhythms: parametric Bayesian classifier under the Gaussian hypothesis (supervised) and agglomerative hierarchical clustering (unsupervised). Qualitative results obtained by using the kappa coefficient and the obtained clusters corroborated the effectiveness of the proposed method.

  5. Musical genres: beating to the rhythms of different drums

    Science.gov (United States)

    Correa, Debora C.; Saito, Jose H.; Costa, Luciano da F.

    2010-05-01

    Online music databases have increased significantly as a consequence of the rapid growth of the Internet and digital audio, requiring the development of faster and more efficient tools for music content analysis. Musical genres are widely used to organize music collections. In this paper, the problem of automatic single and multi-label music genre classification is addressed by exploring rhythm-based features obtained from a respective complex network representation. A Markov model is built in order to analyse the temporal sequence of rhythmic notation events. Feature analysis is performed by using two multivariate statistical approaches: principal components analysis (unsupervised) and linear discriminant analysis (supervised). Similarly, two classifiers are applied in order to identify the category of rhythms: parametric Bayesian classifier under the Gaussian hypothesis (supervised) and agglomerative hierarchical clustering (unsupervised). Qualitative results obtained by using the kappa coefficient and the obtained clusters corroborated the effectiveness of the proposed method.

  6. Photoperiodic regulation of the hamster testis: dependence on circadian rhythms

    International Nuclear Information System (INIS)

    Eskes, G.A.; Zucker, I.

    1978-01-01

    The testes of hamsters exposed to short days (10 hr of light per day) regress within 13 weeks. Administration of 7.5 percent deuterium oxide to hamsters lengthens the period of free running circadian activity rhythms by 2.2 percent and prevents testicular regression during short-day exposure. This is consistent with predictions derived from an external coincidence model for photoperiodic time measurement: Deuterium oxide changes phase relationships between the light-dark cycle and the circadian system, the hamster's daily photosensitive phase is stimulated with light during short days, and the testes remain large. Conservation of the period of circadian rhythms within narrow limits has adaptive significance for hamster photoperiodism and for the occurrence and phasing of the annual reproductive cycle

  7. Hericium erinaceus extracts alter behavioral rhythm in mice.

    Science.gov (United States)

    Furuta, Shoko; Kuwahara, Rika; Hiraki, Eri; Ohnuki, Koichiro; Yasuo, Shinobu; Shimizu, Kuniyoshi

    2016-01-01

    Hericium erinaceus (HE), an edible mushroom, has been used as a herbal medicine in several Asian countries since ancient times. HE has potential as a medicine for the treatment and prevention of dementia, a disorder closely linked with circadian rhythm. This study investigated the effects of the intake of HE extracts on behavioral rhythm, photosensitivity of the circadian clock, and clock gene mRNA expression in the suprachiasmatic nucleus (SCN), a central clock, in mice. Although the HE ethanol extract only affected the offset time of activity, the HE water extract advanced the sleep-wake cycle without affecting the free-running period, photosensitivity, or the clock gene mRNA expression in SCN. In addition, both extracts decreased wakefulness around end of active phase. The findings of the present study suggest that HE may serve as a functional food in the prevention and treatment of Alzheimer's disease and delayed sleep phase syndrome.

  8. Musical genres: beating to the rhythms of different drums

    International Nuclear Information System (INIS)

    Correa, Debora C; Costa, Luciano da F; Saito, Jose H

    2010-01-01

    Online music databases have increased significantly as a consequence of the rapid growth of the Internet and digital audio, requiring the development of faster and more efficient tools for music content analysis. Musical genres are widely used to organize music collections. In this paper, the problem of automatic single and multi-label music genre classification is addressed by exploring rhythm-based features obtained from a respective complex network representation. A Markov model is built in order to analyse the temporal sequence of rhythmic notation events. Feature analysis is performed by using two multivariate statistical approaches: principal components analysis (unsupervised) and linear discriminant analysis (supervised). Similarly, two classifiers are applied in order to identify the category of rhythms: parametric Bayesian classifier under the Gaussian hypothesis (supervised) and agglomerative hierarchical clustering (unsupervised). Qualitative results obtained by using the kappa coefficient and the obtained clusters corroborated the effectiveness of the proposed method.

  9. Interval analysis of interictal EEG: pathology of the alpha rhythm in focal epilepsy

    Science.gov (United States)

    Pyrzowski, Jan; Siemiński, Mariusz; Sarnowska, Anna; Jedrzejczak, Joanna; Nyka, Walenty M.

    2015-11-01

    The contemporary use of interictal scalp electroencephalography (EEG) in the context of focal epilepsy workup relies on the visual identification of interictal epileptiform discharges. The high-specificity performance of this marker comes, however, at a cost of only moderate sensitivity. Zero-crossing interval analysis is an alternative to Fourier analysis for the assessment of the rhythmic component of EEG signals. We applied this method to standard EEG recordings of 78 patients divided into 4 subgroups: temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE), psychogenic nonepileptic seizures (PNES) and nonepileptic patients with headache. Interval-analysis based markers were capable of effectively discriminating patients with epilepsy from those in control subgroups (AUC~0.8) with diagnostic sensitivity potentially exceeding that of visual analysis. The identified putative epilepsy-specific markers were sensitive to the properties of the alpha rhythm and displayed weak or non-significant dependences on the number of antiepileptic drugs (AEDs) taken by the patients. Significant AED-related effects were concentrated in the theta interval range and an associated marker allowed for identification of patients on AED polytherapy (AUC~0.9). Interval analysis may thus, in perspective, increase the diagnostic yield of interictal scalp EEG. Our findings point to the possible existence of alpha rhythm abnormalities in patients with epilepsy.

  10. Influences of rhythm- and timbre-related musical features on characteristics of music-induced movement.

    Science.gov (United States)

    Burger, Birgitta; Thompson, Marc R; Luck, Geoff; Saarikallio, Suvi; Toiviainen, Petri

    2013-01-01

    Music makes us move. Several factors can affect the characteristics of such movements, including individual factors or musical features. For this study, we investigated the effect of rhythm- and timbre-related musical features as well as tempo on movement characteristics. Sixty participants were presented with 30 musical stimuli representing different styles of popular music, and instructed to move along with the music. Optical motion capture was used to record participants' movements. Subsequently, eight movement features and four rhythm- and timbre-related musical features were computationally extracted from the data, while the tempo was assessed in a perceptual experiment. A subsequent correlational analysis revealed that, for instance, clear pulses seemed to be embodied with the whole body, i.e., by using various movement types of different body parts, whereas spectral flux and percussiveness were found to be more distinctly related to certain body parts, such as head and hand movement. A series of ANOVAs with the stimuli being divided into three groups of five stimuli each based on the tempo revealed no significant differences between the groups, suggesting that the tempo of our stimuli set failed to have an effect on the movement features. In general, the results can be linked to the framework of embodied music cognition, as they show that body movements are used to reflect, imitate, and predict musical characteristics.

  11. Influences of rhythm- and timbre-related musical features on characteristics of music-induced movement

    Directory of Open Access Journals (Sweden)

    Birgitta eBurger

    2013-04-01

    Full Text Available Music makes us move. Several factors can affect the characteristics of such movements, including individual factors or musical features. For this study, we investigated the effect of rhythm- and timbre-related musical features as well as tempo on movement characteristics. Sixty participants were presented with 30 musical stimuli representing different styles of popular music, and instructed to move along with the music. Optical motion capture was used to record participants’ movements. Subsequently, eight movement features and four rhythm- and timbre-related musical features were computationally extracted from the data, while the tempo was assessed in a perceptual experiment. A subsequent correlational analysis revealed that, for instance, clear pulses seemed to be embodied with the whole body, i.e., by using various movement types of different body parts, whereas spectral flux and percussiveness were found to be more distinctly related to certain body parts, such as head and hand movement. A series of ANOVAs with the stimuli being divided into three groups of five stimuli each based on the tempo revealed no significant differences between the groups, suggesting that the tempo of our stimuli set failed to have an effect on the movement features. In general, the results can be linked to the framework of embodied music cognition, as they show that body movements are used to reflect, imitate, and predict musical characteristics.

  12. Stable isotope ratios in hair and teeth reflect biologic rhythms.

    Directory of Open Access Journals (Sweden)

    Otto Appenzeller

    Full Text Available Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.

  13. Transitions between beta and gamma rhythms in neural systems

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Setsinsky, D.; Fausbøll, Anders

    2002-01-01

    We study the coexistence of different rhythms in a local network of one inhibitory and two excitatory nerve cells for a wide range of the excitatory synapse strength and of the slow K+-channel conductance. The dynamic features of spike trains in the presence of noise are discussed. It is found...... that noise can both cause switching between different states and induce coherent firing events....

  14. Air Travel, Circadian Rhythms/Hormones, and Autoimmunity.

    Science.gov (United States)

    Torres-Ruiz, J; Sulli, A; Cutolo, M; Shoenfeld, Y

    2017-08-01

    Biological rhythms are fundamental for homeostasis and have recently been involved in the regulatory processes of various organs and systems. Circadian cycle proteins and hormones have a direct effect on the inflammatory response and have shown pro- or anti-inflammatory effects in animal models of autoimmune diseases. The cells of the immune system have their own circadian rhythm, and the light-dark cycle directly influences the inflammatory response. On the other hand, patients with autoimmune diseases characteristically have sleep disorders and fatigue, and in certain disease, such as rheumatoid arthritis (RA), a frank periodicity in the signs and symptoms is recognized. The joint symptoms predominate in the morning, and apparently, subjects with RA have relative adrenal insufficiency, with a cortisol peak unable to control the late night load of pro-inflammatory cytokines. Transatlantic flights represent a challenge in the adjustment of biological rhythms, since they imply sleep deprivation, time zone changes, and potential difficulties for drug administration. In patients with autoimmune diseases, the use of DMARDs and prednisone at night is probably best suited to lessen morning symptoms. It is also essential to sleep during the trip to improve adaptation to the new time zone and to avoid, as far as possible, works involving flexible or nocturnal shifts. The study of proteins and hormones related to biological rhythms will demonstrate new pathophysiological pathways of autoimmune diseases, which will emphasize the use of general measures for sleep respect and methods for drug administration at key daily times to optimize their anti-inflammatory and immune modulatory effects.

  15. Chorusing, synchrony and the evolutionary functions of rhythm

    Directory of Open Access Journals (Sweden)

    Andrea eRavignani

    2014-10-01

    Full Text Available A central goal of biomusicology is to understand the biological basis of human musicality. One approach to this problem has been to compare core components of human musicality (relative pitch perception, entrainment, etc. with similar capacities in other animal species. Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony, we argue for the central importance of temporal properties, and propose that this domain is ripe for further comparative research. Second, whereas most rhythm research in non-human animals has examined animal timing in isolation, we consider how chorusing dynamics can shape individual timing, as in human music and dance, making group behavior key to understand the adaptive functions of rhythm. To illustrate the interdependence between individual and chorusing dynamics, we present a computational model of chorusing agents relating individual call timing with synchronous group behavior. Third, we distinguish and clarify mechanistic and functional explanations of rhythmic phenomena, often conflated in the literature, arguing that this distinction is key for understanding the evolution of musicality. Fourth, we expand biomusicological discussions beyond the species typically considered, providing an overview of chorusing and rhythmic behavior across a broad range of taxa (orthopterans, fireflies, frogs, birds, and primates. Finally, we propose an Evolving Signal Timing hypothesis, suggesting that similarities between timing abilities in biological species will be based on comparable chorusing behaviors. We conclude that the comparative study of chorusing species can provide important insights into the adaptive function(s of rhythmic behavior in our proto-musical primate ancestors, and thus inform our understanding of the biology and evolution of rhythm in human music and

  16. Chorusing, synchrony, and the evolutionary functions of rhythm.

    Science.gov (United States)

    Ravignani, Andrea; Bowling, Daniel L; Fitch, W Tecumseh

    2014-01-01

    A central goal of biomusicology is to understand the biological basis of human musicality. One approach to this problem has been to compare core components of human musicality (relative pitch perception, entrainment, etc.) with similar capacities in other animal species. Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony), we argue for the central importance of temporal properties, and propose that this domain is ripe for further comparative research. Second, whereas most rhythm research in non-human animals has examined animal timing in isolation, we consider how chorusing dynamics can shape individual timing, as in human music and dance, arguing that group behavior is key to understanding the adaptive functions of rhythm. To illustrate the interdependence between individual and chorusing dynamics, we present a computational model of chorusing agents relating individual call timing with synchronous group behavior. Third, we distinguish and clarify mechanistic and functional explanations of rhythmic phenomena, often conflated in the literature, arguing that this distinction is key for understanding the evolution of musicality. Fourth, we expand biomusicological discussions beyond the species typically considered, providing an overview of chorusing and rhythmic behavior across a broad range of taxa (orthopterans, fireflies, frogs, birds, and primates). Finally, we propose an "Evolving Signal Timing" hypothesis, suggesting that similarities between timing abilities in biological species will be based on comparable chorusing behaviors. We conclude that the comparative study of chorusing species can provide important insights into the adaptive function(s) of rhythmic behavior in our "proto-musical" primate ancestors, and thus inform our understanding of the biology and evolution of rhythm in human music and

  17. Dynamic correlations between heart and brain rhythm during Autogenic meditation

    OpenAIRE

    Kim, Dae-Keun; Lee, Kyung-Mi; Kim, Jongwha; Whang, Min-Cheol; Kang, Seung Wan

    2013-01-01

    This study is aimed to determine significant physiological parameters of brain and heart under meditative state, both in each activities and their dynamic correlations. Electrophysiological changes in response to meditation were explored in 12 healthy volunteers who completed 8 weeks of a basic training course in autogenic meditation. Heart coherence, representing the degree of ordering in oscillation of heart rhythm intervals, increased significantly during meditation. Relative EEG alpha pow...

  18. Circadian activity rhythms for mothers with an infant in ICU

    Directory of Open Access Journals (Sweden)

    Shih-Yu eLee

    2010-12-01

    Full Text Available Circadian rhythms influence sleep and wakefulness. Circadian activity rhythms (CAR are altered in individuals with dementia or seasonal affective disorder. To date, studies exploring CAR and sleep in postpartum women are rare. The purpose of this report is to describe relationships between CAR, sleep disturbance, and fatigue among 72 first-time mothers during their 2nd week postpartum while their newborn remain hospitalized in intensive care unit (ICU. Seventy two mothers were included in this secondary data analysis sample from three separate studies. Participants completed the General Sleep Disturbance Scale (GSDS, Numerical Rating Scale for Fatigue (NRS-F, and a sleep diary. The objective sleep data included total sleep time (TST, wake after sleep onset (WASO, and CAR determined by the circadian quotient (amplitude/mesor averaged from at least 48-hours of wrist actigraphy monitoring. The TST of mothers who self-reported as poor sleepers was 354 minutes (SEM= 21.9, with a mean WASO of 19.5% (SEM= 2.8. The overall sleep quality measured by the GSDS was clinically, significantly disrupted (M= 5.5, SD= 1.2. The mean score for morning fatigue was 5.8 (SD= 2.0, indicating moderate fatigue severity. The CAR was .62 (SEM= .04, indicating poor synchronization. The self-reported good sleepers (GSDS < 3 had better CAR (M= .71, SEM= .02 than poor sleepers (GSDS > 3 (t [70] = 2.0, p< .05. A higher circadian equation was associated with higher TST (r= .83, p<.001, less WASO (r= -.50, p< .001, lower self-reported sleep disturbance scores (r= -.35, p= .01, and less morning fatigue (r= -.26. Findings indicate that mothers with a hospitalized infant have both nocturnal sleep problems and disturbed circadian activity rhythms. Factors responsible for these sleep and rhythm disturbances, the adverse effects on mother’s physical and mental well-being, and mother-infant relationship require further study.

  19. Multiple Scale Music Segmentation Using Rhythm, Timbre, and Harmony

    Directory of Open Access Journals (Sweden)

    Kristoffer Jensen

    2007-01-01

    Full Text Available The segmentation of music into intro-chorus-verse-outro, and similar segments, is a difficult topic. A method for performing automatic segmentation based on features related to rhythm, timbre, and harmony is presented, and compared, between the features and between the features and manual segmentation of a database of 48 songs. Standard information retrieval performance measures are used in the comparison, and it is shown that the timbre-related feature performs best.

  20. The emerging importance of ultradian glucocorticoid rhythms within metabolic pathology.

    Science.gov (United States)

    Flynn, Benjamin P; Conway-Campbell, Becky L; Lightman, Stafford L

    2018-06-01

    Glucocorticoid (GC) hormones play significant roles within homeostasis and the chrono-dynamics of their regulatory role has become increasingly recognised within dysregulated GC pathology, particularly with metabolic phenotypes. Within this article, we will discuss the relevance of the ultradian homeostatic rhythm, how its dysregulation effects glucocorticoid receptor and RNA polymeraseII recruitment and may play a significant role within aberrant metabolic action. Copyright © 2018 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  1. Light and Cognition: Roles for Circadian Rhythms, Sleep, and Arousal

    Science.gov (United States)

    Fisk, Angus S.; Tam, Shu K. E.; Brown, Laurence A.; Vyazovskiy, Vladyslav V.; Bannerman, David M.; Peirson, Stuart N.

    2018-01-01

    Light exerts a wide range of effects on mammalian physiology and behavior. As well as synchronizing circadian rhythms to the external environment, light has been shown to modulate autonomic and neuroendocrine responses as well as regulating sleep and influencing cognitive processes such as attention, arousal, and performance. The last two decades have seen major advances in our understanding of the retinal photoreceptors that mediate these non-image forming responses to light, as well as the neural pathways and molecular mechanisms by which circadian rhythms are generated and entrained to the external light/dark (LD) cycle. By contrast, our understanding of the mechanisms by which lighting influences cognitive processes is more equivocal. The effects of light on different cognitive processes are complex. As well as the direct effects of light on alertness, indirect effects may also occur due to disrupted circadian entrainment. Despite the widespread use of disrupted LD cycles to study the role circadian rhythms on cognition, the different experimental protocols used have subtly different effects on circadian function which are not always comparable. Moreover, these protocols will also disrupt sleep and alter physiological arousal, both of which are known to modulate cognition. Studies have used different assays that are dependent on different cognitive and sensory processes, which may also contribute to their variable findings. Here, we propose that studies addressing the effects of different lighting conditions on cognitive processes must also account for their effects on circadian rhythms, sleep, and arousal if we are to fully understand the physiological basis of these responses. PMID:29479335

  2. Visible light alters yeast metabolic rhythms by inhibiting respiration

    OpenAIRE

    Robertson, James Brian; Davis, Chris R.; Johnson, Carl Hirschie

    2013-01-01

    In some organisms, respiration fluctuates cyclically, and these rhythms can be a sensitive gauge of metabolism. Constant or pulsatile exposure of yeast to visible wavelengths of light significantly alters and/or initiates these respiratory oscillations, revealing a further dimension of the challenges to yeast living in natural environments. Our results also have implications for the use of light as research tools—e.g., for excitation of fluorescence microscopically—even in organisms such as y...

  3. CIRCADIAN RHYTHMS FROM MULTIPLE OSCILLATORS: LESSONS FROM DIVERSE ORGANISMS

    OpenAIRE

    Bell-Pedersen, Deborah; Cassone, Vincent M.; Earnest, David J.; Golden, Susan S.; Hardin, Paul E.; Thomas, Terry L.; Zoran, Mark J.

    2005-01-01

    The organization of biological activities into daily cycles is universal in organisms as diverse as cyanobacteria, fungi, algae, plants, flies, birds and man. Comparisons of circadian clocks in unicellular and multicellular organisms using molecular genetics and genomics have provided new insights into the mechanisms and complexity of clock systems. Whereas unicellular organisms require stand-alone clocks that can generate 24-hour rhythms for diverse processes, organisms with differentiated t...

  4. Action experience, more than observation, influences mu rhythm desynchronization.

    Directory of Open Access Journals (Sweden)

    Erin N Cannon

    Full Text Available Since the discovery of mirror neurons in premotor and parietal areas of the macaque monkey, the idea that action and perception may share the same neural code has been of central interest in social, developmental, and cognitive neurosciences. A fundamental question concerns how a putative human mirror neuron system may be tuned to the motor experiences of the individual. The current study tested the hypothesis that prior motor experience modulated the sensorimotor mu and beta rhythms. Specifically, we hypothesized that these sensorimotor rhythms would be more desynchronized after active motor experience compared to passive observation experience. To test our hypothesis, we collected EEG from adult participants during the observation of a relatively novel action: an experimenter used a claw-like tool to pick up a toy. Prior to EEG collection, we trained one group of adults to perform this action with the tool (performers. A second group comprised trained video coders, who only had experience observing the action (observers. Both the performers and the observers had no prior motor and visual experience with the action. A third group of novices was also tested. Performers exhibited the greatest mu rhythm desynchronization in the 8-13 Hz band, particularly in the right hemisphere compared to observers and novices. This study is the first to contrast active tool-use experience and observation experience in the mu rhythm and to show modulation with relatively shorter amounts of experience than prior mirror neuron expertise studies. These findings are discussed with respect to its broader implication as a neural signature for a mechanism of early social learning.

  5. A multimodal spectral approach to characterize rhythm in natural speech.

    Science.gov (United States)

    Alexandrou, Anna Maria; Saarinen, Timo; Kujala, Jan; Salmelin, Riitta

    2016-01-01

    Human utterances demonstrate temporal patterning, also referred to as rhythm. While simple oromotor behaviors (e.g., chewing) feature a salient periodical structure, conversational speech displays a time-varying quasi-rhythmic pattern. Quantification of periodicity in speech is challenging. Unimodal spectral approaches have highlighted rhythmic aspects of speech. However, speech is a complex multimodal phenomenon that arises from the interplay of articulatory, respiratory, and vocal systems. The present study addressed the question of whether a multimodal spectral approach, in the form of coherence analysis between electromyographic (EMG) and acoustic signals, would allow one to characterize rhythm in natural speech more efficiently than a unimodal analysis. The main experimental task consisted of speech production at three speaking rates; a simple oromotor task served as control. The EMG-acoustic coherence emerged as a sensitive means of tracking speech rhythm, whereas spectral analysis of either EMG or acoustic amplitude envelope alone was less informative. Coherence metrics seem to distinguish and highlight rhythmic structure in natural speech.

  6. Sleep, circadian rhythm and body weight: parallel developments.

    Science.gov (United States)

    Westerterp-Plantenga, Margriet S

    2016-11-01

    Circadian alignment is crucial for body-weight management, and for metabolic health. In this context, circadian alignment consists of alignment of sleep, meal patterns and physical activity. During puberty a significant reduction in sleep duration occurs, and pubertal status is inversely associated with sleep duration. A consistent inverse association between habitual sleep duration and body-weight development occurs, independent of possible confounders. Research on misalignment reveals that circadian misalignment affects sleep-architecture and subsequently disturbs glucose-insulin metabolism, substrate oxidation, leptin- and ghrelin concentrations, appetite, food reward, hypothalamic-pituitary-adrenal-axis activity and gut-peptide concentrations enhancing positive energy balance and metabolic disturbance. Not only aligning meals and sleep in a circadian way is crucial, also regular physical activity during the day strongly promotes the stability and amplitude of circadian rhythm, and thus may serve as an instrument to restore poor circadian rhythms. Endogenicity may play a role in interaction of these environmental variables with a genetic predisposition. In conclusion, notwithstanding the separate favourable effects of sufficient daily physical activity, regular meal patterns, sufficient sleep duration and quality sleep on energy balance, the overall effect of the amplitude and stability of the circadian rhythm, perhaps including genetic predisposition, may integrate the separate effects in an additive way.

  7. Visual Timing of Structured Dance Movements Resembles Auditory Rhythm Perception

    Science.gov (United States)

    Su, Yi-Huang; Salazar-López, Elvira

    2016-01-01

    Temporal mechanisms for processing auditory musical rhythms are well established, in which a perceived beat is beneficial for timing purposes. It is yet unknown whether such beat-based timing would also underlie visual perception of temporally structured, ecological stimuli connected to music: dance. In this study, we investigated whether observers extracted a visual beat when watching dance movements to assist visual timing of these movements. Participants watched silent videos of dance sequences and reproduced the movement duration by mental recall. We found better visual timing for limb movements with regular patterns in the trajectories than without, similar to the beat advantage for auditory rhythms. When movements involved both the arms and the legs, the benefit of a visual beat relied only on the latter. The beat-based advantage persisted despite auditory interferences that were temporally incongruent with the visual beat, arguing for the visual nature of these mechanisms. Our results suggest that visual timing principles for dance parallel their auditory counterparts for music, which may be based on common sensorimotor coupling. These processes likely yield multimodal rhythm representations in the scenario of music and dance. PMID:27313900

  8. Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis

    Science.gov (United States)

    Hausdorff, J. M.; Lertratanakul, A.; Cudkowicz, M. E.; Peterson, A. L.; Kaliton, D.; Goldberger, A. L.

    2000-01-01

    Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

  9. Dual Gamma Rhythm Generators Control Interlaminar Synchrony in Auditory Cortex

    Science.gov (United States)

    Ainsworth, Matthew; Lee, Shane; Cunningham, Mark O.; Roopun, Anita K.; Traub, Roger D.; Kopell, Nancy J.; Whittington, Miles A.

    2013-01-01

    Rhythmic activity in populations of cortical neurons accompanies, and may underlie, many aspects of primary sensory processing and short-term memory. Activity in the gamma band (30 Hz up to > 100 Hz) is associated with such cognitive tasks and is thought to provide a substrate for temporal coupling of spatially separate regions of the brain. However, such coupling requires close matching of frequencies in co-active areas, and because the nominal gamma band is so spectrally broad, it may not constitute a single underlying process. Here we show that, for inhibition-based gamma rhythms in vitro in rat neocortical slices, mechanistically distinct local circuit generators exist in different laminae of rat primary auditory cortex. A persistent, 30 – 45 Hz, gap-junction-dependent gamma rhythm dominates rhythmic activity in supragranular layers 2/3, whereas a tonic depolarization-dependent, 50 – 80 Hz, pyramidal/interneuron gamma rhythm is expressed in granular layer 4 with strong glutamatergic excitation. As a consequence, altering the degree of excitation of the auditory cortex causes bifurcation in the gamma frequency spectrum and can effectively switch temporal control of layer 5 from supragranular to granular layers. Computational modeling predicts the pattern of interlaminar connections may help to stabilize this bifurcation. The data suggest that different strategies are used by primary auditory cortex to represent weak and strong inputs, with principal cell firing rate becoming increasingly important as excitation strength increases. PMID:22114273

  10. Redox rhythm reinforces the circadian clock to gate immune response.

    Science.gov (United States)

    Zhou, Mian; Wang, Wei; Karapetyan, Sargis; Mwimba, Musoki; Marqués, Jorge; Buchler, Nicolas E; Dong, Xinnian

    2015-07-23

    Recent studies have shown that in addition to the transcriptional circadian clock, many organisms, including Arabidopsis, have a circadian redox rhythm driven by the organism's metabolic activities. It has been hypothesized that the redox rhythm is linked to the circadian clock, but the mechanism and the biological significance of this link have only begun to be investigated. Here we report that the master immune regulator NPR1 (non-expressor of pathogenesis-related gene 1) of Arabidopsis is a sensor of the plant's redox state and regulates transcription of core circadian clock genes even in the absence of pathogen challenge. Surprisingly, acute perturbation in the redox status triggered by the immune signal salicylic acid does not compromise the circadian clock but rather leads to its reinforcement. Mathematical modelling and subsequent experiments show that NPR1 reinforces the circadian clock without changing the period by regulating both the morning and the evening clock genes. This balanced network architecture helps plants gate their immune responses towards the morning and minimize costs on growth at night. Our study demonstrates how a sensitive redox rhythm interacts with a robust circadian clock to ensure proper responsiveness to environmental stimuli without compromising fitness of the organism.

  11. A New Perspective for Parkinson's Disease: Circadian Rhythm.

    Science.gov (United States)

    Li, Siyue; Wang, Yali; Wang, Fen; Hu, Li-Fang; Liu, Chun-Feng

    2017-02-01

    Circadian rhythm is manifested by the behavioral and physiological changes from day to night, which is controlled by the pacemaker and its regulator. The former is located at the suprachiasmatic nuclei (SCN) in the anterior hypothalamus, while the latter is composed of clock genes present in all tissues. Circadian desynchronization influences normal patterns of day-night rhythms such as sleep and alertness cycles, rest and activity cycles. Parkinson's disease (PD) exhibits diurnal fluctuations. Circadian dysfunction has been observed in PD patients and animal models, which may result in negative consequences to the homeostasis and even exacerbate the disease progression. Therefore, circadian therapies, including light stimulation, physical activity, dietary and social schedules, may be helpful for PD patients. However, the cellular and molecular mechanisms that underlie the circadian dysfunction in PD remain elusive. Further research on circadian patterns is needed. This article summarizes the existing research on the circadian rhythms in PD, focusing on the clinical symptom variations, molecular changes, as well as the available treatment options.

  12. The Paradox of Isochrony in the Evolution of Human Rhythm

    Directory of Open Access Journals (Sweden)

    Andrea Ravignani

    2017-11-01

    Full Text Available Isochrony is crucial to the rhythm of human music. Some neural, behavioral and anatomical traits underlying rhythm perception and production are shared with a broad range of species. These may either have a common evolutionary origin, or have evolved into similar traits under different evolutionary pressures. Other traits underlying rhythm are rare across species, only found in humans and few other animals. Isochrony, or stable periodicity, is common to most human music, but isochronous behaviors are also found in many species. It appears paradoxical that humans are particularly good at producing and perceiving isochronous patterns, although this ability does not conceivably confer any evolutionary advantage to modern humans. This article will attempt to solve this conundrum. To this end, we define the concept of isochrony from the present functional perspective of physiology, cognitive neuroscience, signal processing, and interactive behavior, and review available evidence on isochrony in the signals of humans and other animals. We then attempt to resolve the paradox of isochrony by expanding an evolutionary hypothesis about the function that isochronous behavior may have had in early hominids. Finally, we propose avenues for empirical research to examine this hypothesis and to understand the evolutionary origin of isochrony in general.

  13. Alignment strategies for the entrainment of music and movement rhythms.

    Science.gov (United States)

    Moens, Bart; Leman, Marc

    2015-03-01

    Theories of entrainment assume that spontaneous entrainment emerges from dynamic laws that operate via mediators on interactions, whereby entrainment is facilitated if certain conditions are fulfilled. In this study, we show that mediators can be built that affect the entrainment of human locomotion to music. More specifically, we built D-Jogger, a music player that functions as a mediator between music and locomotion rhythms. The D-Jogger makes it possible to manipulate the timing differences between salient moments of the rhythms (beats and footfalls) through the manipulation of the musical period and phase, which affect the condition in which entrainment functions. We conducted several experiments to explore different strategies for manipulating the entrainment of locomotion and music. The results of these experiments showed that spontaneous entrainment can be manipulated, thereby suggesting different strategies on how to embark. The findings furthermore suggest a distinction among different modalities of entrainment: finding the beat (the most difficult part of entrainment), keeping the beat (easier, as a temporal scheme has been established), and being in phase (no entrainment is needed because the music is always adapted to the human rhythm). This study points to a new avenue of research on entrainment and opens new perspectives for the neuroscience of music. © 2014 New York Academy of Sciences.

  14. Daily rhythm of phosphoenolpyruvate carboxylase in Crassulacean acid metabolism plants : Immunological evidence for the absence of a rhythm in protein synthesis.

    Science.gov (United States)

    Brulfert, J; Vidal, J; Gadal, P; Queiroz, O

    1982-11-01

    Immunotitration of phosphoenolpyruvate carboxylase (EC 4.1.1.31) extracted from leaves of Kalanchoe blossfeldiana v. Poelln. cv. Tom Thumb. It was established that at different times of the day-night cycle the daily rhythm of enzyme capacity does not result from a rhythm in protein synthesis, but rather from changes in the specific activity of the enzyme.

  15. Extended Schmidt law holds for faint dwarf irregular galaxies

    Science.gov (United States)

    Roychowdhury, Sambit; Chengalur, Jayaram N.; Shi, Yong

    2017-12-01

    Context. The extended Schmidt law (ESL) is a variant of the Schmidt which relates the surface densities of gas and star formation, with the surface density of stellar mass added as an extra parameter. Although ESL has been shown to be valid for a wide range of galaxy properties, its validity in low-metallicity galaxies has not been comprehensively tested. This is important because metallicity affects the crucial atomic-to-molecular transition step in the process of conversion of gas to stars. Aims: We empirically investigate for the first time whether low metallicity faint dwarf irregular galaxies (dIrrs) from the local universe follow the ESL. Here we consider the "global" law where surface densities are averaged over the galactic discs. dIrrs are unique not only because they are at the lowest end of mass and star formation scales for galaxies, but also because they are metal-poor compared to the general population of galaxies. Methods: Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) which is the largest survey of atomic hydrogen in such galaxies. The gas surface densities are determined using their atomic hydrogen content. The star formation rates are calculated using GALEX far ultraviolet fluxes after correcting for dust extinction, whereas the stellar surface densities are calculated using Spitzer 3.6 μm fluxes. The surface densities are calculated over the stellar discs defined by the 3.6 μm images. Results: We find dIrrs indeed follow the ESL. The mean deviation of the FIGGS galaxies from the relation is 0.01 dex, with a scatter around the relation of less than half that seen in the original relation. In comparison, we also show that the FIGGS galaxies are much more deviant when compared to the "canonical" Kennicutt-Schmidt relation. Conclusions: Our results help strengthen the universality of the ESL, especially for galaxies with low metallicities. We suggest that models of star formation in which feedback from previous generations

  16. Irregular Saturnian Moon Lightcurves from Cassini-ISS Observations: Update

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2013-10-01

    Cassini ISS-NAC observations of the irregular moons of Saturn revealed various physical information on these objects. 16 synodic rotational periods: Hati (S43): 5.45 h; Mundilfari (S25): 6.74 h; Suttungr (S23): ~7.4 h; Kari (S45): 7.70 h; Siarnaq (S29): 10.14 h; Tarvos (S21): 10.66 h; Ymir (S19, sidereal period): 11.92220 h ± 0.1 s; Skathi (S27): ~12 h; Hyrrokkin (S44): 12.76 h; Ijiraq (S22): 13.03 h; Albiorix (S26): 13.32 h; Bestla (S39): 14.64 h; Bebhionn (S37): ~15.8 h; Kiviuq (S24): 21.82 h; Thrymr (S30): ~27 h; Erriapus (S28): ~28 h. The average period for the prograde-orbiting moons is ~16 h, for the retrograde moons ~11½ h (includes Phoebe's 9.2735 h from Bauer et al., AJ, 2004). Phase-angle dependent behavior of lightcurves: The phase angles of the observations range from 2° to 105°. The lightcurves which were obtained at low phase (<40°) show the 2-maxima/ 2-minima pattern expected for this kind of objects. At higher phases, more complicated lightcurves emerge, giving rough indications on shapes. Ymir pole and shape: For satellite Ymir, a convex-hull shape model and the pole-axis orientation have been derived. Ymir's north pole points toward λ = 230°±180°, β = -85°±10°, or RA = 100°±20°, Dec = -70°±10°. This is anti-parallel to the rotation axes of the major planets, indicating that Ymir not just orbits, but also rotates in a retrograde sense. The shape of Ymir resembles a triangular prism with edge lengths of ~20, ~24, and ~25 km. The ratio between the longest 25 km) and shortest axis (pole axis, ~15 km) is ~1.7. Erriapus seasons: The pole direction of object Erriapus has probably a low ecliptic latitude. This gives this moon seasons similar to the Uranian regular moons with periods where the sun stands very high in the sky over many years, and with years-long periods of permanent night. Hati density: The rotational frequency of the fastest rotator (Hati) is close to the frequency where the object would lose material from the surface if

  17. Energetic efficiency, menstrual irregularity, and bone mineral density in elite professional female ballet dancers.

    Science.gov (United States)

    Doyle-Lucas, Ashley F; Akers, Jeremy D; Davy, Brenda M

    2010-01-01

    Sports that emphasize low body weight for optimal performance, such as ballet, are associated with an increased prevalence of the female athlete triad (FT). Previous research in this area that involves dancers has been limited; the majority of studies have been performed on adolescents training in classical ballet, and not professional adult dancers. The purpose of this study is to compare the physical and behavioral characteristics of female elite ballet dancers to sedentary, recreationally active non-dancing controls, with regard to characteristics of the FT and energetic efficiency. Women aged 18 to 35 years were recruited as participants. The dancers (N = 15) and non-dancing controls (N = 15) were pair-matched via age (dancers: 24.3 ± 1.3 years; controls: 23.7 ± 0.9 years), body mass index (dancers: 18.9 ± 0.2; controls: 19.4 ± 0.2 kg/m 2 ), and fat-free mass (dancers: 44.3 ± 0.8; controls: 44.1 ± 0.9 kg). Assessments included habitual dietary intake using 4-day food records, self-reported physical activity, psychometric measures of eating behaviors, health and menstrual history, body composition and bone density (dual energy x-ray absorptiometry), and resting metabolic rate (RMR) assessed by indirect calorimetry. Characteristics of the FT, specifically menstrual irregularities (6 of 15 dancers reported irregular or no menses; 1 of 15 controls reported irregular menses) and low energy availability, were more prevalent in dancers than in pair-matched controls. Despite having a similar fat-free mass (FFM), dancers had a significantly lower absolute RMR (dancers: 1367 ± 27; controls: 1454 ± 34 kcal/d; p ≤ 0.05) and significantly lower RMR relative to FFM (dancers: 30.9 ± 0.6; controls: 33.1 ± 0.8 kcal/kg fat-free mass/d; p ≤ 0.05). Energy intake between dancers (1577 ± 89 kcal/d) and pair-matched controls (2075 ± 163 kcal/d) also differed significantly (p ≤ 0.01). Six of the 15 dancers met the criteria for the FT (including low bone mineral

  18. Validation of 3D documentation of palatal soft tissue shape, color, and irregularity with intraoral scanning.

    Science.gov (United States)

    Deferm, Julie T; Schreurs, Ruud; Baan, Frank; Bruggink, Robin; Merkx, Matthijs A W; Xi, Tong; Bergé, Stefaan J; Maal, Thomas J J

    2018-04-01

    The purpose of this study was to assess the feasibility of 3D intraoral scanning for documentation of palatal soft tissue by evaluating the accuracy of shape, color, and curvature. Intraoral scans of ten participants' upper dentition and palate were acquired with the TRIOS® 3D intraoral scanner by two observers. Conventional impressions were taken and digitized as a gold standard. The resulting surface models were aligned using an Iterative Closest Point approach. The absolute distance measurements between the intraoral models and the digitized impression were used to quantify the trueness and precision of intraoral scanning. The mean color of the palatal soft tissue was extracted in HSV (hue, saturation, value) format to establish the color precision. Finally, the mean curvature of the surface models was calculated and used for surface irregularity. Mean average distance error between the conventional impression models and the intraoral models was 0.02 ± 0.07 mm (p = 0.30). Mean interobserver color difference was - 0.08 ± 1.49° (p = 0.864), 0.28 ± 0.78% (p = 0.286), and 0.30 ± 1.14% (p = 0.426) for respectively hue, saturation, and value. The interobserver differences for overall and maximum surface irregularity were 0.01 ± 0.03 and 0.00 ± 0.05 mm. This study supports the hypothesis that the intraoral scan can perform a 3D documentation of palatal soft tissue in terms of shape, color, and curvature. An intraoral scanner can be an objective tool, adjunctive to the clinical examination of the palatal tissue.

  19. Design and development of a content-based medical image retrieval system for spine vertebrae irregularity.

    Science.gov (United States)

    Mustapha, Aouache; Hussain, Aini; Samad, Salina Abdul; Zulkifley, Mohd Asyraf; Diyana Wan Zaki, Wan Mimi; Hamid, Hamzaini Abdul

    2015-01-16

    Content-based medical image retrieval (CBMIR) system enables medical practitioners to perform fast diagnosis through quantitative assessment of the visual information of various modalities. In this paper, a more robust CBMIR system that deals with both cervical and lumbar vertebrae irregularity is afforded. It comprises three main phases, namely modelling, indexing and retrieval of the vertebrae image. The main tasks in the modelling phase are to improve and enhance the visibility of the x-ray image for better segmentation results using active shape model (ASM). The segmented vertebral fractures are then characterized in the indexing phase using region-based fracture characterization (RB-FC) and contour-based fracture characterization (CB-FC). Upon a query, the characterized features are compared to the query image. Effectiveness of the retrieval phase is determined by its retrieval, thus, we propose an integration of the predictor model based cross validation neural network (PMCVNN) and similarity matching (SM) in this stage. The PMCVNN task is to identify the correct vertebral irregularity class through classification allowing the SM process to be more efficient. Retrieval performance between the proposed and the standard retrieval architectures are then compared using retrieval precision (Pr@M) and average group score (AGS) measures. Experimental results show that the new integrated retrieval architecture performs better than those of the standard CBMIR architecture with retrieval results of cervical (AGS > 87%) and lumbar (AGS > 82%) datasets. The proposed CBMIR architecture shows encouraging results with high Pr@M accuracy. As a result, images from the same visualization class are returned for further used by the medical personnel.

  20. ON THE STAR FORMATION LAW FOR SPIRAL AND IRREGULAR GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G., E-mail: bge@us.ibm.com [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

    2015-12-01

    A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical timescale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical timescale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ∼100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.

  1. Influence of Ionospheric Irregularities on GNSS Remote Sensing

    Directory of Open Access Journals (Sweden)

    M. V. Tinin

    2015-01-01

    Full Text Available We have used numerical simulation to study the effects of ionospheric irregularities on accuracy of global navigation satellite system (GNSS measurements, using ionosphere-free (in atmospheric research and geometry-free (in ionospheric research dual-frequency phase combinations. It is known that elimination of these effects from multifrequency GNSS measurements is handi-capped by diffraction effects during signal propagation through turbulent ionospheric plasma with the inner scale being smaller than the Fresnel radius. We demonstrated the possibility of reducing the residual ionospheric error in dual-frequency GNSS remote sensing in ionosphere-free combination by Fresnel inversion. The inversion parameter, the distance to the virtual screen, may be selected from the minimum of amplitude fluctuations. This suggests the possibility of improving the accuracy of GNSS remote sensing in meteorology. In the study of ionospheric disturbances with the aid of geometry-free combination, the Fresnel inversion eliminates only the third-order error. To eliminate the random TEC component which, like the measured average TEC, is the first-order correction, we should use temporal filtering (averaging.

  2. Timing irregularities of PSR J1705-1906

    Science.gov (United States)

    Liu, Y. L.; Yuan, J. P.; Wang, J. B.; Liu, X. W.; Wang, N.; Yuen, R.

    2018-05-01

    Timing analysis of PSR J1705-1906 using data from Nanshan 25-m and Parkes 64-m radio telescopes, which span over fourteen years, shows that the pulsar exhibits significant proper motion, and rotation instability. We updated the astrometry parameters and the spin parameters of the pulsar. In order to minimize the effect of timing irregularities on measuring its position, we employ the Cholesky method to analyse the timing noise. We obtain the proper motion of -77(3) mas yr-1 in right ascension and -38(29) mas yr-1 in declination. The power spectrum of timing noise is analyzed for the first time, which gives the spectral exponent α =-5.2 for the power-law model indicating that the fluctuations in spin frequency and spin-down rate dominate the red noise. We detect two small glitches from this pulsar with fractional jump in spin frequency of Δ ν /ν ˜ 2.9 × 10^{-10} around MJD 55199 and Δ ν /ν ˜ 2.7× 10^{-10} around MJD 55953. Investigations of pulse profile at different time segments suggest no significant changes in the pulse profiles around the two glitches.

  3. Distributed sensing of ionospheric irregularities with a GNSS receiver array

    Science.gov (United States)

    Su, Yang; Datta-Barua, Seebany; Bust, Gary S.; Deshpande, Kshitija B.

    2017-08-01

    We present analysis methods for studying the structuring and motion of ionospheric irregularities at the subkilometer scale sizes that produce L band scintillations. Spaced-receiver methods are used for Global Navigation Satellite System (GNSS) receivers' phase measurements over approximately subkilometer to kilometer length baselines for the first time. The quantities estimated by these techniques are plasma drift velocity, diffraction anisotropy magnitude and orientation, and characteristic velocity. Uncertainties are quantified by ensemble simulation of noise on the phase signals carried through to the observations of the spaced-receiver linear system. These covariances are then propagated through to uncertainties on drifts through linearization about the estimated values of the state. Five receivers of SAGA, the Scintillation Auroral Global Positioning System (GPS) Array, provide 100 Hz power and phase data for each channel at L1 frequency. The array is sited in the auroral zone at Poker Flat Research Range, Alaska. A case study of a single scintillating satellite observed by the array is used to demonstrate the spaced-receiver and uncertainty estimation process. A second case study estimates drifts as measured by multiple scintillating channels. These scintillations are correlated with auroral activity, based on all-sky camera images. Measurements and uncertainty estimates made over a 30 min period are compared to a collocated incoherent scatter radar and show good agreement in horizontal drift speed and direction during periods of scintillation for which the characteristic velocity is less than the drift velocity.

  4. Metallicity of Young and Old Stars in Irregular Galaxies

    Science.gov (United States)

    Tikhonov, N. A.

    2018-01-01

    Based on archived images obtained with the Hubble Space Telescope, stellar photometry for 105 irregular galaxies has been conducted. We have shown the red supergiant and giant branches in the obtained Hertzsprung-Russel diagrams. Using the TRGB method, distances to galaxies and metallicity of red giants have been determined. The color index ( V - I) of the supergiant branch at the luminosity level M I = -7 was chosen as the metallicity index of red supergiants. For the galaxies under study, the diagrams have been built, in which the correlation can be seen between the luminosity of galaxies ( M B ) and metallicity of red giants and supergiants. The main source of variance of the results in the obtained diagrams is, in our opinion, uncertainty inmeasurements of galaxy luminosities and star-forming outburst. The relation between metallicity of young and old stars shows that main enrichment of galaxies with metals has taken place in the remote past. Deviations of some galaxies in the obtained relation can possibly be explained with the fall of the intergalactic gas on them, although, this inconsiderably affects metallicities of the stellar content.

  5. Climatic irregular staircases: generalized acceleration of global warming.

    Science.gov (United States)

    De Saedeleer, Bernard

    2016-01-27

    Global warming rates mentioned in the literature are often restricted to a couple of arbitrary periods of time, or of isolated values of the starting year, lacking a global view. In this study, we perform on the contrary an exhaustive parametric analysis of the NASA GISS LOTI data, and also of the HadCRUT4 data. The starting year systematically varies between 1880 and 2002, and the averaging period from 5 to 30 yr - not only decades; the ending year also varies . In this way, we uncover a whole unexplored space of values for the global warming rate, and access the full picture. Additionally, stairstep averaging and linear least squares fitting to determine climatic trends have been sofar exclusive. We propose here an original hybrid method which combines both approaches in order to derive a new type of climatic trend. We find that there is an overall acceleration of the global warming whatever the value of the averaging period, and that 99.9% of the 3029 Earth's climatic irregular staircases are rising. Graphical evidence is also given that choosing an El Niño year as starting year gives lower global warming rates - except if there is a volcanic cooling in parallel. Our rates agree and generalize several results mentioned in the literature.

  6. Propagating star formation and irregular structure in spiral galaxies

    International Nuclear Information System (INIS)

    Mueller, M.W.; Arnett, W.D.

    1976-01-01

    A simple model is proposed which describes the irregular optical appearance often seen in late-type spiral galaxies. If high-mass stars produce spherical shock waves which induce star formation, new high-mass stars will be born which, in turn, produce new shock waves. When this process operates in a differentially rotating disk, our numerical model shows that large-scale spiral-shaped regions of star formation are built up. The structure is seen to be most sensitive to a parameter which governs how often a region of the interstellar medium can undergo star formation. For a proper choice of this parameter, large-scale features disappear before differential rotation winds them up. New spiral features continuously form, so some spiral structure is seen indefinitely. The structure is not the classical two-armed symmetric spiral pattern which the density-wave theory attempts to explain, but it is asymmetric and disorderly.The mechanism of propagating star formation used in our model is consistent with observations which connect young OB associations with expanding shells of gas. We discuss the possible interaction of this mechanism with density waves

  7. Weighted statistical parameters for irregularly sampled time series

    Science.gov (United States)

    Rimoldini, Lorenzo

    2014-01-01

    Unevenly spaced time series are common in astronomy because of the day-night cycle, weather conditions, dependence on the source position in the sky, allocated telescope time and corrupt measurements, for example, or inherent to the scanning law of satellites like Hipparcos and the forthcoming Gaia. Irregular sampling often causes clumps of measurements and gaps with no data which can severely disrupt the values of estimators. This paper aims at improving the accuracy of common statistical parameters when linear interpolation (in time or phase) can be considered an acceptable approximation of a deterministic signal. A pragmatic solution is formulated in terms of a simple weighting scheme, adapting to the sampling density and noise level, applicable to large data volumes at minimal computational cost. Tests on time series from the Hipparcos periodic catalogue led to significant improvements in the overall accuracy and precision of the estimators with respect to the unweighted counterparts and those weighted by inverse-squared uncertainties. Automated classification procedures employing statistical parameters weighted by the suggested scheme confirmed the benefits of the improved input attributes. The classification of eclipsing binaries, Mira, RR Lyrae, Delta Cephei and Alpha2 Canum Venaticorum stars employing exclusively weighted descriptive statistics achieved an overall accuracy of 92 per cent, about 6 per cent higher than with unweighted estimators.

  8. Irregular persistent activity induced by synaptic excitatory feedback

    Directory of Open Access Journals (Sweden)

    Francesca Barbieri

    2007-11-01

    Full Text Available Neurophysiological experiments on monkeys have reported highly irregular persistent activity during the performance of an oculomotor delayed-response task. These experiments show that during the delay period the coefficient of variation (CV of interspike intervals (ISI of prefrontal neurons is above 1, on average, and larger than during the fixation period. In the present paper, we show that this feature can be reproduced in a network in which persistent activity is induced by excitatory feedback, provided that (i the post-spike reset is close enough to threshold , (ii synaptic efficacies are a non-linear function of the pre-synaptic firing rate. Non-linearity between presynaptic rate and effective synaptic strength is implemented by a standard short-term depression mechanism (STD. First, we consider the simplest possible network with excitatory feedback: a fully connected homogeneous network of excitatory leaky integrate-and-fire neurons, using both numerical simulations and analytical techniques. The results are then confirmed in a network with selective excitatory neurons and inhibition. In both the cases there is a large range of values of the synaptic efficacies for which the statistics of firing of single cells is similar to experimental data.

  9. Walking to the beat of different drums: practical implications for the use of acoustic rhythms in gait rehabilitation.

    Science.gov (United States)

    Roerdink, Melvyn; Bank, Paulina J M; Peper, C Lieke E; Beek, Peter J

    2011-04-01

    Acoustic rhythms are frequently used in gait rehabilitation, with positive instantaneous and prolonged transfer effects on various gait characteristics. The gait modifying ability of acoustic rhythms depends on how well gait is tied to the beat, which can be assessed with measures of relative timing of auditory-motor coordination. We examined auditory-motor coordination in 20 healthy elderly individuals walking to metronome beats with pacing frequencies slower than, equal to, and faster than their preferred cadence. We found that more steps were required to adjust gait to the beat, the more the metronome rate deviated from the preferred cadence. Furthermore, participants anticipated the beat with their footfalls to various degrees, depending on the metronome rate; the faster the tempo, the smaller the phase advance or phase lead. Finally, the variability in the relative timing between footfalls and the beat was smaller for metronome rates closer to the preferred cadence, reflecting superior auditory-motor coordination. These observations have three practical implications. First, instantaneous effects of acoustic stimuli on gait characteristics may typically be underestimated given the considerable number of steps required to attune gait to the beat in combination with the usual short walkways. Second, a systematic phase lead of footfalls to the beat does not necessarily reflect a reduced ability to couple gait to the metronome. Third, the efficacy of acoustic rhythms to modify gait depends on metronome rate. Gait is coupled best to the beat for metronome rates near the preferred cadence. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Daily Rhythms of Hunger and Satiety in Healthy Men during One Week of Sleep Restriction and Circadian Misalignment.

    Science.gov (United States)

    Sargent, Charli; Zhou, Xuan; Matthews, Raymond W; Darwent, David; Roach, Gregory D

    2016-01-29

    The impact of sleep restriction on the endogenous circadian rhythms of hunger and satiety were examined in 28 healthy young men. Participants were scheduled to 2 × 24-h days of baseline followed by 8 × 28-h days of forced desynchrony during which sleep was either moderately restricted (equivalent to 6 h in bed/24 h; n = 14) or severely restricted (equivalent to 4 h in bed/24 h; n = 14). Self-reported hunger and satisfaction were assessed every 2.5 h during wake periods using visual analogue scales. Participants were served standardised meals and snacks at regular intervals and were not permitted to eat ad libitum. Core body temperature was continuously recorded with rectal thermistors to determine circadian phase. Both hunger and satiety exhibited a marked endogenous circadian rhythm. Hunger was highest, and satiety was lowest, in the biological evening (i.e., ~17:00-21:00 h) whereas hunger was lowest, and satiety was highest in the biological night (i.e., 01:00-05:00 h). The results are consistent with expectations based on previous reports and may explain in some part the decrease in appetite that is commonly reported by individuals who are required to work at night. Interestingly, the endogenous rhythms of hunger and satiety do not appear to be altered by severe--as compared to moderate--sleep restriction.

  11. Daily Rhythms of Hunger and Satiety in Healthy Men during One Week of Sleep Restriction and Circadian Misalignment

    Directory of Open Access Journals (Sweden)

    Charli Sargent

    2016-01-01

    Full Text Available The impact of sleep restriction on the endogenous circadian rhythms of hunger and satiety were examined in 28 healthy young men. Participants were scheduled to 2 × 24-h days of baseline followed by 8 × 28-h days of forced desynchrony during which sleep was either moderately restricted (equivalent to 6 h in bed/24 h; n = 14 or severely restricted (equivalent to 4 h in bed/24 h; n = 14. Self-reported hunger and satisfaction were assessed every 2.5 h during wake periods using visual analogue scales. Participants were served standardised meals and snacks at regular intervals and were not permitted to eat ad libitum. Core body temperature was continuously recorded with rectal thermistors to determine circadian phase. Both hunger and satiety exhibited a marked endogenous circadian rhythm. Hunger was highest, and satiety was lowest, in the biological evening (i.e., ~17:00–21:00 h whereas hunger was lowest, and satiety was highest in the biological night (i.e., 01:00–05:00 h. The results are consistent with expectations based on previous reports and may explain in some part the decrease in appetite that is commonly reported by individuals who are required to work at night. Interestingly, the endogenous rhythms of hunger and satiety do not appear to be altered by severe—as compared to moderate—sleep restriction.

  12. Heart Rhythm Monitoring in the Constellation Lunar and Launch/Landing EVA Suit: Recommendations from an Expert Panel

    Science.gov (United States)

    Scheuring, Richard A.; Hamilton, Doug; Jones, Jeffrey A.; Alexander, David

    2009-01-01

    There are currently several physiological monitoring requirements for EVA in the Human-Systems Interface Requirements (HSIR) document. There are questions as to whether the capability to monitor heart rhythm in the lunar surface space suit is a necessary capability for lunar surface operations. Similarly, there are questions as to whether the capability to monitor heart rhythm during a cabin depressurization scenario in the launch/landing space suit is necessary. This presentation seeks to inform space medicine personnel of recommendations made by an expert panel of cardiovascular medicine specialists regarding in-suit ECG heart rhythm monitoring requirements during lunar surface operations. After a review of demographic information and clinical cases and panel discussion, the panel recommended that ECG monitoring capability as a clinical tool was not essential in the lunar space suit; ECG monitoring was not essential in the launch/landing space suit for contingency scenarios; the current hear rate monitoring capability requirement for both launch/landing and lunar space suits should be maintained; lunar vehicles should be required to have ECG monitoring capability with a minimum of 5-lead ECG for IVA medical assessments; and, exercise stress testing for astronaut selection and retention should be changed from the current 85% maximum heart rate limit to maximal, exhaustive 'symptom-limited' testing to maximize diagnostic utility as a screening tool for evaluating the functional capacity of astronauts and their cardiovascular health.

  13. Reviewing the musical component of rhythm of "poetry" and the factors influencing it

    Directory of Open Access Journals (Sweden)

    Ma’sumeh Ma’dankan

    2017-04-01

    Full Text Available ‘Rhythm’ is the most important component in the music of poetry. In this paper, in addition to defining rhythm, we have studied relative components which have most influence on the music of poetry. ‘Rhythm’ is the first common factor in different arts especially music and poetry. Poetry has always been along with rhythm. A short and complete definition of ‘rhythm’ is: “Rhythm is the balance resulting from sequence of letters or rhythms at certain limited times”.The most important factors affecting rhythm are: Proportion of syllables at prosodic rhythms: Every syllable has its special musical load at prosodic rhythms. It is clear that if each of them is mostly used at one rhythm, it will mostly and clearly show its own special state. Sequence of syllables at prosodic rhythms: Succession of long or short syllables because of their special vocal effect on rhythm is very effective on the musical quality of rhythm. Application of long syllable: The most the number of long syllables in a verse, the heavier will be the rhythm of the verse. Because in this way the number of syllables of every verse will be decreased and their temporal duration will be increased. Conformity of the end of words with the end of elements (space between words with space between elements: conformity of the end of words and elements because of the repeated sequence of an element highly strengthens the effect of that prosodic element at the mind of the listener. These constant and repeated scansions make the poem rhythmic and enrich its music. Making accidental or the second rhythm: one way for innovation and overcoming the natural music of a rhythm is making a special rhythm other than the main prosodic rhythm of poem by arranging the words in a special order in a way that it conforms to the other scansion of the same prosodic rhythm. Using regular space between words other than space of elements: sometimes the poet without using a different scansion of the

  14. Interplay of intrinsic and synaptic conductances in the generation of high-frequency oscillations in interneuronal networks with irregular spiking.

    Directory of Open Access Journals (Sweden)

    Fabiano Baroni

    2014-05-01

    Full Text Available High-frequency oscillations (above 30 Hz have been observed in sensory and higher-order brain areas, and are believed to constitute a general hallmark of functional neuronal activation. Fast inhibition in interneuronal networks has been suggested as a general mechanism for the generation of high-frequency oscillations. Certain classes of interneurons exhibit subthreshold oscillations, but the effect of this intrinsic neuronal property on the population rhythm is not completely understood. We study the influence of intrinsic damped subthreshold oscillations in the emergence of collective high-frequency oscillations, and elucidate the dynamical mechanisms that underlie this phenomenon. We simulate neuronal networks composed of either Integrate-and-Fire (IF or Generalized Integrate-and-Fire (GIF neurons. The IF model displays purely passive subthreshold dynamics, while the GIF model exhibits subthreshold damped oscillations. Individual neurons receive inhibitory synaptic currents mediated by spiking activity in their neighbors as well as noisy synaptic bombardment, and fire irregularly at a lower rate than population frequency. We identify three factors that affect the influence of single-neuron properties on synchronization mediated by inhibition: i the firing rate response to the noisy background input, ii the membrane potential distribution, and iii the shape of Inhibitory Post-Synaptic Potentials (IPSPs. For hyperpolarizing inhibition, the GIF IPSP profile (factor iii exhibits post-inhibitory rebound, which induces a coherent spike-mediated depolarization across cells that greatly facilitates synchronous oscillations. This effect dominates the network dynamics, hence GIF networks display stronger oscillations than IF networks. However, the restorative current in the GIF neuron lowers firing rates and narrows the membrane potential distribution (factors i and ii, respectively, which tend to decrease synchrony. If inhibition is shunting instead

  15. Interplay of intrinsic and synaptic conductances in the generation of high-frequency oscillations in interneuronal networks with irregular spiking.

    Science.gov (United States)

    Baroni, Fabiano; Burkitt, Anthony N; Grayden, David B

    2014-05-01

    High-frequency oscillations (above 30 Hz) have been observed in sensory and higher-order brain areas, and are believed to constitute a general hallmark of functional neuronal activation. Fast inhibition in interneuronal networks has been suggested as a general mechanism for the generation of high-frequency oscillations. Certain classes of interneurons exhibit subthreshold oscillations, but the effect of this intrinsic neuronal property on the population rhythm is not completely understood. We study the influence of intrinsic damped subthreshold oscillations in the emergence of collective high-frequency oscillations, and elucidate the dynamical mechanisms that underlie this phenomenon. We simulate neuronal networks composed of either Integrate-and-Fire (IF) or Generalized Integrate-and-Fire (GIF) neurons. The IF model displays purely passive subthreshold dynamics, while the GIF model exhibits subthreshold damped oscillations. Individual neurons receive inhibitory synaptic currents mediated by spiking activity in their neighbors as well as noisy synaptic bombardment, and fire irregularly at a lower rate than population frequency. We identify three factors that affect the influence of single-neuron properties on synchronization mediated by inhibition: i) the firing rate response to the noisy background input, ii) the membrane potential distribution, and iii) the shape of Inhibitory Post-Synaptic Potentials (IPSPs). For hyperpolarizing inhibition, the GIF IPSP profile (factor iii)) exhibits post-inhibitory rebound, which induces a coherent spike-mediated depolarization across cells that greatly facilitates synchronous oscillations. This effect dominates the network dynamics, hence GIF networks display stronger oscillations than IF networks. However, the restorative current in the GIF neuron lowers firing rates and narrows the membrane potential distribution (factors i) and ii), respectively), which tend to decrease synchrony. If inhibition is shunting instead of

  16. "Needed Not Wanted": An Interdisciplinary Examination of the Work-Related Challenges Faced by Irregular Migrants

    Science.gov (United States)

    Marfleet, Philip; Blustein, David L.

    2011-01-01

    Using an integrative perspective drawn from vocational psychology and migration studies, this article explores the lives of irregular migrants, which represents a unique aspect of work-based migration. Irregular migrants are those individuals who travel from regions without much work to states that offer some means of employment, without formal…

  17. Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transciption typewriting

    NARCIS (Netherlands)

    Bloemsaat, J.G.; Galen, G.P. van; Meulenbroek, R.G.J.

    2003-01-01

    This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly

  18. The Relationships among Cognitive Correlates and Irregular Word, Non-Word, and Word Reading

    Science.gov (United States)

    Abu-Hamour, Bashir; University, Mu'tah; Urso, Annmarie; Mather, Nancy

    2012-01-01

    This study explored four hypotheses: (a) the relationships among rapid automatized naming (RAN) and processing speed (PS) to irregular word, non-word, and word reading; (b) the predictive power of various RAN and PS measures, (c) the cognitive correlates that best predicted irregular word, non-word, and word reading, and (d) reading performance of…

  19. Influence of initial stress, irregularity and heterogeneity on Love-type ...

    Indian Academy of Sciences (India)

    The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half- space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface.

  20. Crime among irregular immigrants and the influence of internal border control

    NARCIS (Netherlands)

    Leerkes, A.S.; Engbersen, G.; Leun, van der J.P.

    2012-01-01

    Abstract Both the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants