29 resultados para Ultradian rhythms

em Deakin Research Online - Australia


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In this article I present some theoretical perspectives on reflective practice and African music. As reflection is a voyage of on-going self-discovery and change, and most challenging, I consider the teaching of African music across two continents and institutions. After a recent visit to South Africa (August-October 2006), I describe and discuss some similarities that I as a music educator at Deakin University, share with a music educator from the University of the North West, South Africa regarding the teaching and learning of African music. Through observation and interview data with my colleague, I offer some thoughts on what is African music and why we teach different rhythms to similar tunes across two continents at our tertiary institutions. I see this as a way forward to transmit and promote togetherness in a multicultural society where we respect diversity and the notion of 'other'.

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Large disruptions of chronobiological rhythms are documented as destabilizing individuals with bipolar disorder; however, the impact of small phase altering events is unclear. Australian suicide data from 1971 to 2001 were assessed to determine the impact on the number of suicides of a 1-h time shift due to daylight saving. The results confirm that male suicide rates rise in the weeks following the commencement of daylight saving, compared to the weeks following the return to eastern standard time and for the rest of the year. After adjusting for the season, prior to 1986 suicide rates in the weeks following the end of daylight saving remained significantly increased compared to the rest of autumn. This study suggests that small changes in chronobiological rhythms are potentially destabilizing in vulnerable individuals.

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The circadian system regulates 24 hour rhythms in biological creatures. It impacts mood regulation. The disruptions of circadian rhythms cause destabilization in individuals with affective disorders, such as depression and bipolar disorders. Previous work has examined the role of the circadian system on effects of light interactions on mood-related systems, the effects of light manipulation on brain, the impact of chronic stress on rhythms. However, such studies have been conducted in small, preselected populations. The deluge of data is now changing the landscape of research practice. The unprecedented growth of social media data allows one to study individual behavior across large and diverse populations. In particular, individuals with affective disorders from online communities have not been examined rigorously. In this paper, we aim to use social media as a sensor to identify circadian patterns for individuals with affective disorders in online communities.We use a large scale study cohort of data collecting from online affective disorder communities. We analyze changes in hourly, daily, weekly and seasonal affect of these clinical groups in contrast with control groups of general communities. By comparing the behaviors between the clinical groups and the control groups, our findings show that individuals with affective disorders show a significant distinction in their circadian rhythms across the online activity. The results shed light on the potential of using social media for identifying diurnal individual variation in affective state, providing key indicators and risk factors for noninvasive wellbeing monitoring and prediction.

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Meal-fed conscious rabbits normally exhibit postprandial elevation in blood pressure, heart rate (HR) and locomotor activity, which is abolished by consumption of a high-fat diet (HFD). Here, we assessed whether the cardiovascular changes are attributable to the increased caloric intake due to greater fat content or to hyperphagia. Rabbits were meal-fed during the baseline period then maintained on either an ad libitum normal fat diet (NFD) or ad libitum HFD for 2 weeks. Blood pressure, HR and locomotor activity were measured daily by radio-telemetry alongside food intake and body weight. Caloric intake in rabbits given a NFD ad libitum rose 50% from baseline but there were no changes in cardiovascular parameters. By contrast, HR increased by 10% on the first day of the ad libitum HFD (p<0.001) prior to any change in body weight while blood pressure increased 7% after 4d (p<0.01) and remained elevated. Baseline 24-h patterns of blood pressure and HR were closely associated with mealtime, characterised by afternoon peaks and morning troughs. When the NFD was changed from meal-fed to ad libitum, blood pressure and HR did not change but afternoon activity levels decreased (p<0.05). By contrast, after 13d ad libitum HFD, morning HR, blood pressure and activity increased by 20%, 8% and 71%, respectively. Increased caloric intake specifically from fat, but not as a result of hyperphagia, appears to directly modulate cardiovascular homeostasis and circadian patterns, independent of white adipose tissue accumulation.

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In young European starlings, as in other avian species, high-amplitude 24-hr rhythms in plasma and pineal melatonin are already present around the time of hatching. In chickens this rhythmicity results at least partly from the light sensitivity of the melatonin-producing and -secreting system. In contrast to the chicken, the starling is a hole-nesting bird, and it seemed questionable whether the low light intensities in the nest are sufficient to synchronize perinatal melatonin rhythms. We therefore exposed starling eggs to light cycles roughly simulating those measured in nest-boxes, i.e., an 11-hr phase of complete darkness and a 13-hr phase consisting of 15 min of dim light (10 lux) alternating with 30 min of darkness. For one group the photophase lasted from 0600 to 1900 hr; for the other group the photophase lasted from 1800 to 0700 hr. In approximately 10-hr-old hatchlings of both groups, plasma and pineal melatonin concentrations were high during the dark phase and low during the light phase. We conclude that perinatal low-amplitude light intensity changes of the kind experienced by hatching starlings in the field are sufficient for synchronizing the melatonin-producing and -secreting system in the pineal and possibly other organs.

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With each new object and phenomena humankind discovers, develops or invents, a new set of words must be coined or adopted to describe them. Words are not neutral, carrying with them associations and connotations based on their previous applications and alliances, and augmented by their shapes, sounds, rhymes and rhythms. Many words which are now embedded in lCT's, retain and continue to be colored by these earlier meanings, some of which are drawn from myths.The method of vocabulary-building utilized by ICT's reflects its openness to new ideas and users.

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The discovery, development or invention of new objects and phenomena by humankind, requires a new set of words to be coined or adopted to describe it. This is also true of the Information Communication Technology (ICT) world. Words are not neutral, regardless of which dialect or language they occur in. They carry with them associations and connotations based on their previous applications and alliances, and augmented by their shapes, sounds, rhymes and rhythms. The subtext that word choice creates, while often not recognised or acknowledged, is important in considering how communication operates in, and shapes Information Technology (IT) environments. Many words that are now embedded in the ICT lexicon continue to be informed by these earlier meanings, some of which, in the English lexis, are drawn from myths. The vernacular of the ICT lexis reflects its openness to new ideas, the nature of its users, its English language roots and its Western cultural origins. This contributes to a particular communication style. But such lexis can prove problematic for non-English speaking background users and/or those from different cultures. As the ICT vocabulary continues to evolve, these language and cultural underpinnings are coming under challenge, suggesting a language and cultural future very different to the past. This in turn, will create a subtext that affects all users.

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Fish oil (FO)- and canola oil (CO)-based diets were regularly alternated in a daily cycle (amCO: alternation of CO in the morning and FO in the afternoon, and pmCO: alternation of FO in the morning and CO in the afternoon) or in a series of weekly cycles (2W: alternation of 2 weeks on CO and 2 weeks on FO, 4W: alternation of 4 weeks on CO and 4 weeks on FO), over a 16-week period in juvenile Murray cod (Maccullochella peelii peelii). No significant differences were observed between any of the treatments in relation to the final weight. However, fish subjected to the 2W schedule were larger (P>0.05) than all other treatments (37.2 ± 0.30 vs. 34.3 ± 0.58 in the control treatment). Fish receiving the 2W treatment had a significantly lower total net disappearance of eicosapentaenoic acid 20:5n-3 (EPA) and docosahexaenoic acid 22:6n-3 (62.1% and 24.0% respectively) compared with the control treatment (fish continuously fed a blend of 50% FO and 50% CO). Likewise, Murray cod receiving the amCO daily schedule had a significantly lower total net disappearance of EPA in comparison with the CD and pmCO treatments. These data point towards the existence of cyclical mechanisms relative to fatty acid utilization/retention.

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Chronic Fatigue Syndrome (CFS) is a debilitating condition in which severe, ongoing fatigue is the most prominent of a complex of somatic, psychological and neuropsychological symptoms. The aetiology of CFS remains uncertain and, to date, efforts to distinguish a clear pathophysiological profile for the disorder have been unsuccessful. Current evidence suggests that, rather than being a discrete disease entity with a single cause, CFS is a clinical condition resulting from the interaction of a number of pathophysiological factors, including acute infections, stress and psychiatric disorder. Recently, there has been some interest in the proposition that disordered circadian time-keeping may contribute to the development and/or course of the illness. The rationale for the investigation of circadian factors in CFS is based on the fact that disorders known to be associated with circadian dysregulation, such as jet lag and shiftwork related syndromes have a high degree of symptomatological overlap with CFS. Also, the presence of circadian disturbance could account, in part, for other phenomenological aspects of CFS, including the high rates of comorbid affective disturbance, and the reports of low-level immune dyregulation among sufferers. While several recent studies have produced some evidence of chronobiological dysregulation in CFS patients, much work remains before conclusions can be drawn about the presence, nature and clinical significance of circadian disturbance in CFS. This thesis describes a series of studies that were designed to systematically investigate: 1. whether CFS is associated with a state of circadian dysregulation, and 2. whether circadian dysregulation contributes significantly to the symptomatology of CFS. The first of the 5 studies reported here compared the circadian patterns of sleep-activity of CFS sufferers with those of healthy controls. Results indicated that CFS patients' sleep-activity cycles were significantly phase delayed compared to controls, and that some aspects of their circadian profiles of sleep-activity were related to some measures of sleep-disturbance and well-being. Studies 2 and 3 investigated the relationship between rhythms of sleep-wake and core temperature in CFS patients and healthy controls. The major finding from these studies was that sleep-wake and core temperature rhythms appear to be less effectively synchronised. Further evidence was collected that suggested that there was a relationship between circadian parameters and symptom measures in the CFS group. While this indicated that circadian dysregulation is linked in some way to the symptoms of CFS, assessment of the actual clinical significance of circadian disturbances required the use of a prospective methodology. The final two studies, therefore, report on a placebo-controlled trial of clinical interventions that were designed to restore circadian integrity to CFS patients, in order to see whether this would lead to a reduction in symptom number or severity. Results indicated that, although patients experienced improvements across a range of measures of symptoms and functional capacity, these were small in magnitude, of unlikely clinical significance, and no greater, in general, to improvements reported by patients who underwent placebo treatment. These results, along with those of the earlier studies, are discussed with respect to their implications regarding the presence and significance of circadian dysregulation. It is concluded that, while they provide evidence that CFS is associated with a degree of both internal and external circadian desynchrony, these findings suggest that circadian dysregulation is likely to be only a peripheral, contributor to the processes that generate and maintain the symptom complex. These findings are discussed with respect to how they contribute to our overall understanding of this multi-dimensional condition, and the implications they have for the continuing effort to investigate the causes and treatment of CFS.

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Since 1998, debate has occurred over whether light synchronises the human biological clock through the visual system only, or if the light penetrating our skin is also influential. This thesis provides definitive, debate ending, evidence that skin exposure to even intensely bright light has no impact on circadian timing. The portfolio presents a review of the literature regarding the efficacy of dialectical behavior therapy as a treatment for borderline personality disorder, a summary of the proposed mechanisms of action on the various treatment components, and a description of the clinical application of the four 'skills training modules' via the use of four case study examples.

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This paper presents a new study on the application of the framework of Computational Media Aesthetics to the problem of automated understanding of film. Leveraging Film Grammar as the means to closing the "semantic gap" in media analysis, we examine film rhythm, a powerful narrative concept used to endow structure and form to the film compositionally and enhance its lyrical quality experientially. The novelty of this paper lies in the specification and investigation of the rhythmic elements that are present in two cinematic devices; namely motion and editing patterns, and their potential usefulness to automated content annotation and management systems. In our rhythm model, motion behavior is classified as being either nonexistent, fluid or staccato for a given shot. Shot neighborhoods in movies are then grouped by proportional makeup of these motion behavioral classes to yield seven high-level rhythmic arrangements that prove to be adept at indicating likely scene content (e.g. dialogue or chase sequence) in our experiments. The second part of our investigation presents a computational model to detect editing patterns as either metric, accelerated, decelerated or free. Details of the algorithm for the extraction of these classes are presented, along with experimental results on real movie data. We show with an investigation of combined rhythmic patterns that, while detailed content identification via rhythm types alone is not possible by virtue of the fact that film is not codified to this level in terms of rhythmic elements, analysis of the combined motion/editing rhythms can allow us to determine that the content has changed and hypothesize as to why this is so. We present three such categories of change and demonstrate their efficacy for capturing useful film elements (e.g. scene change precipitated by plot event), by providing data support from five motion pictures.

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We present online algorithms to extract social context: Social spheres are labeled locations of significance, represented as convex hulls extracted from GPS traces. Colocation is determined from Bluetooth and GPS to extract social rhythms, patterns in time, duration, place, and people corresponding to real-world activities. Social ties are formulated from proximity and shared spheres and rhythms. Quantitative evaluation is performed for 10+ million samples over 45 man-months. Applications are presented with assessment of perceived utility: Socio-Graph, a video and photo browser with filters for social metadata, and Jive, a blog browser that uses rhythms to discover similarity between entries automatically.