942 resultados para beat the clock


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The aim of this work was to investigate the effect of the in vitro circadian-like exposure to melatonin [in the presence or absence of insulin (Ins)] on the metabolism and clock gene expression in adipocytes. To simulate the cyclic characteristics of the daily melatonin profile, isolated rat adipocytes were exposed in a circadian-like pattern to melatonin added to the incubating medium for 12 hr (mimicking the night), followed by an equal period without melatonin (mimicking the day) combined or not with Ins. This intermittent incubation was interrupted when four and a half 24-hr cycles were fulfilled. At the end, either during the induced night (melatonin present) or the induced day (melatonin absent), the rates of lipolysis and D-[U-(14)C]-glucose incorporation into lipids were estimated, in addition to the determination of lipogenic [glucose-6-phosphate dehydrogenase and fatty acid synthase (FAS)] and lipolytic (hormone sensitive lipase) enzymes and clock gene (Bmal-1b, Clock, Per-1 and Cry-1) mRNA expression. The leptin release was also measured. During the induced night, the following effects were observed: an increase in the mRNA expression of Clock, Per-1 and FAS; a rise in lipogenic response and leptin secretion; and a decrease in the lipolytic activity. The intermittent exposure of adipocytes to melatonin temporally and rhythmically synchronized their metabolic and hormonal function in a circadian fashion, mimicking what is observed in vivo in animals during the daily light-dark cycle. Therefore, this work helps to clarify the physiological relevance of the circadian pattern of melatonin secretion and its interactions with Ins, contributing to a better understanding of the adipocyte biology.

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The enzyme nitrate reductase (NR) responsible for the conversion of nitrate to nitrite is considered to be the rate-limiting step in nitrogen assimilation. The economically important marine macroalga Gracilaria tenuistipitata presents a circadian oscillation in NR protein content and activity. In order to identify if the regulation of NR in G. tenuistipitata happens at transcriptional levels, the NR cDNA and gene were sequenced and the NR mRNA expression was studied. Analysis of the sequenced gene revealed absence of introns which is unusual for NR genes. The transcriptional profiling revealed a circadian rhythm for NR; furthermore, a rhythm was observed in constant light condition, suggesting a possible regulation by the biological clock at the mRNA levels for NR in G. tenuistipitata.

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The evolutionary history and biogeography of freshwater-dependent taxa in Australia is of intrinsic interest given the present-day aridity of this continent. Cherax is the most widespread and one of the most species-rich of Australia's nine freshwater crayfish genera. The phylogenetic relationships amongst 19 of the 23 Australian Cherax were established from mitochondrial DNA sequences representing the 12S rRNA and 16S rRNA gene regions. The relationships among species support an initial east–west separation, followed by a north–south divergence in eastern Australia. Molecular clock estimations suggest that these divergences date back to the Miocene. The phylogenetic relationships support endemic speciation within geographical regions and indicate that long-distance dispersal has not led to recent speciation as previously hypothesized. This new evolutionary scenario is consistent with the climatic history of Australia and the evolutionary history of other similarly distributed freshwater-dependent organisms in Australia.

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Consistent and stable global states of clock synchronization are very important in distributed and parallel systems. This paper presents an innovative strategy and method to obtain stable global clock synchronization state graphs in asynchronous Internet environments. Our model will introduce the concept of clock precision difference as a means to evaluate running states of all clocks in this system and make this system  self-adaptive well. Finally, we introduce the concept of clock precision difference into global states analysis of clock synchronization and construct clock synchronization state graphs in order to evaluate distributed clock synchronization states. We also present detailed simulations of the strategy and mathematical analysis used on real Internet environments.

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We present an algebraic attack approach to a family of irregularly clock-controlled bit-based linear feedback shift register systems. In the general set-up, we assume that the output bit of one shift register controls the clocking of other registers in the system and produces a family of equations relating the output bits to the internal state bits. We then apply this general theory to four specific stream ciphers: the (strengthened) stop-and-go generator, the alternating step generator, the self-decimated generator and the step1/step2 generator. In the case of the strengthened stop-and-go generator and of the self-decimated generator, we obtain the initial state of the registers in a significantly faster time than any other known attack. In the other two situations, we do better than or as well as all attacks but the correlation attack. In all cases, we demonstrate that the degree of a functional relationship between the registers can be bounded by two. Finally, we determine the effective key length of all four systems.

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In this paper, we mount the first algebraic attacks against clock controlled cascade stream ciphers. We first show how to obtain relations between the internal state bits and the output bits of the Gollmann clock controlled cascade stream ciphers. We demonstrate that the initial states of the last two shift registers can be determined by the initial states of the others. An alternative attack on the Gollmann cascade is also described, which requires solving quadratic equations. We then present an algebraic analysis of Pomaranch, one of the phase two proposals to eSTREAM. A system of equations of maximum degree four that describes the full cipher is derived. We also present weaknesses in the filter functions of Pomaranch by successfully computing annihilators and low degree multiples of the functions.

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This article reports on students' reflections, gathered from questionnaire and interview data, on their learning of rhythm and on their attitudes and  motivation from having engaged with African music as non-music specialists using the Orff approach. The "traditional" Orff approach to classroom music was supplemented with African repertoire which builds on the nexus, identified by Amoaku (1 982), between the Orff method and the traditional way of music learning in African cultures. This article describes my experience as a South African working with Australian non-specialist primary teacher students of predominantly Anglo-Celtic background within the context of a music education unit at Deakin University's Melbourne (Burwood) Campus. As Nketia (1988) points out, I - like many expatriate music educators - have selected music from my own country of origin as the foundation to develop curriculum materials teaching rhythm through non-Western music. The results demonstrate worthwhile experiences and outcomes for both the students and myself.

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Though technology has increased opportunities for students to study online, many students continue to complain of lack of time to study and learn. Using the concepts of clock time and network time, the project combines interview, survey and Australian Bureau of Statistics time diary results to investigate student use and perceptions of their available time to study and how the technologies used in online learning affect this. We concentrate on the amount of time students think they have when studying online, how much time they really use, and what affects this perception of time. Deakin University has specialised in distance education/online learning since its inception in 1974 and long time use of technologies and pedagogies allows widespread and diverse experiences for our students, both on campus and off campus. We study student cohorts of up to 1700 students studying in a single subject online learning space, and note that students in much smaller subject cohorts have similar complaints about time.

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Algebraic attacks have been applied to several types of clock-controlled stream ciphers. However, to date there are no such attacks in the literature on mutually clock-controlled ciphers. In this paper, we present a preliminary step in this direction by giving the first algebraic analysis of mutually clock-controlled feedback shift register stream ciphers: the bilateral stop-and-go generator, A5/1, Alpha 1 and the MICKEY cipher. We show that, if there are no regularly clocked shift registers included in the system, mutually clock-controlled feedback shift register ciphers appear to be highly resistant to algebraic attacks. As a demonstration of the weakness inherent in the presence of a regularly clocked shift register, we present a simple algebraic attack on Alpha 1 based on only 29 keystream bits.

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The isolated Langendorff-mode perfused heart has become a valuable experimental model, used extensively to examine cardiac function, pathophysiology and pharmacology. For the clinical cardiologist an ECG is often a simple practicality, however in experimental circumstances, particularly with ex vivo murine hearts it is not always possible to obtain an ECG due to experimental recording constraints. However, the mechanical record of ventricular contractile function can be highly informative in relation to electrical state. It is difficult though to achieve consistency in these evaluations of arrhythmia as a validated common reference framework is lacking. In 1988, a group of investigators developed the ‘Lambeth Conventions’—a standardised reference for the definition and classification of arrhythmias in animal experimental models of ischaemia, infarction and reperfusion in vivo. Now, two decades later it is timely to revisit the Lambeth Conventions, and to update the guidelines in the context of the marked increase in murine heart study in experimental cardiac pathophysiology. Here we describe an adjunct to the Lambeth Conventions for the reporting of ventricular arrhythmias post-ischaemia in ex vivo mouse hearts when ECG recordings are not employed. Of seven discrete and identifiable patterns of mechanical dysrhythmia observed in reperfusion, five could be classified using conventional ECG terminology: ventricular premature beat, bigeminy, trigeminy, ventricular tachycardia and ventricular fibrillation. Two additional rhythm variations detected from the pressure record are described (potentiated contraction and alternans).

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This article analyses three important inquiries into alcohol licensing in Victoria from 1965 to 1986. It argues that each inquiry was directed to produce a market for alcohol, but the 1986 inquiry, in particular, was directed to produce the conditions for the Night-time Economy. Since the mid-twentieth century, Victoria was considered a bell weather state in relation to alcohol licensing and this was increasingly the case when it comes to the state retreating from control over licensing conditions. From the end of six o'clock closing to the 24 hour city, the inquiries transformed the issues related to alcohol from the problems associated with alcohol consumption to the treatment of alcohol as just another consumer commodity.

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1. Understanding ecological phenomena often requires an accurate assessment of the timing of events. To estimate the time since a diet shift in animals without knowledge on the isotope ratios of either the old or the new diet, isotope ratio measurements in two different tissues (e.g. blood plasma and blood cells) at a single point in time can be used. For this ‘isotopic-clock’ principle, we present here a mathematical model that yields an analytical and easily calculated outcome.

2. Compared with a previously published model, our model assumes the isotopic difference between the old and new diets to be constant if multiple measurements are taken on the same subject at different points in time. Furthermore, to estimate the time since diet switch, no knowledge of the isotopic signature of tissues under the old diet, but only under the new diet is required.

3. The two models are compared using three calibration data sets including a novel one based on a diet shift experiment in a shorebird (red knot Calidris canutus); sensitivity analyses were conducted. The two models behaved differently and each may prove rather unsatisfactory depending on the system under investigation. A single-tissue model, requiring knowledge of both the old and new diets, generally behaved quite reliably.

4. As blood (cells) and plasma are particularly useful tissues for isotopic-clock research, we trawled the literature on turnover rates in whole blood, cells and plasma. Unfortunately, turnover rate predictions using allometric relations are too unreliable to be used directly in isotopic-clock calculations.

5. We advocate that before applying the isotopic-clock methodology, the propagation of error in the ‘time-since-diet-shift’ estimation is carefully assessed for the system under scrutiny using a sensitivity analysis as proposed here.

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Contents

* The international debate about traditional knowledge and approaches in the Asia-Pacific region / Christoph Antons
* How are the different views of traditional knowledge linked by international law and global governance? / Christopher Arup
* Protection of traditional knowledge by geographical indications / Michael Blakeney
* An analysis of WIPO's latest proposal and the Model Law 2002 of the Pacific Community for the Protection of Traditional Cultural Expressions / Silke von Lewinski
* The role of customary law and practice in the protection of traditional knowledge related to biological diversity / Brendan Tobin
* Can modern law safeguard archaic cultural expressions? : observations from a legal sociology perspective / Christoph Beat Graber
* Branding identity and copyrighting culture : orientations towards the customary in traditional knowledge discourse / Martin Chanock
* Being indigenous' in Indonesia and the Philippines / Gerard A. Persoon
* Indigenous heritage and the digital commons / Eric Kansa
* Traditional cultural expression and the internet world / Brian Fitzgerald and Susan Hedge
* Cultural property and "the public domain" : case studies from New Zealand and Australia / Susy Frankel and Megan Richardson
* The recognition of traditional knowledge under Australian biodiscovery regimes : why bother with intellectual property rights? / Natalie Stoianoff
* Protection of traditional knowledge in the SAARC region and India's efforts / S.K. Verma
* The protection of expressions of folklore in Sri Lanka / Indunil Abeyesekere
* Traditional medicine and intellectual property rights : a case study of the Indonesian jamu industry / Christoph Antons and Rosy Antons-Sutanto.


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What were the 1960s really like in Melbourne? Was it just great music, brightly coloured clothes and The Pill? Or was there something deeper and perhaps more insidious happening? This fab new book takes a close look at the many cultural changes of the Sixties and how they affected the Victorian capital - and questions modern-day views about the way times actually did 'a' change'. Go! Melbourne in the Sixties covers defining moments like the visit of The Beatles, the end of the six o'clock closing, political activism, Jean Shrimpton at Flemington, as well as increases in tertiary study opportunities, dramatic population growth through migration and a baby-boom, and sets them in the context of a decade that many continue to see as a golden era.

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Using a turtle-borne camera system, changing flipper beat frequency and amplitude were measured in five diving green turtles (Chelonia mydas Linnaeus 1758) in the Bahía de los Angeles, Mexico (28°58′N, 113°33′W). These observations were made between June and August 2002. Turtles worked hardest (i.e., had the highest flipper beat frequency and amplitude) at the start of descents when positive buoyancy is predicted to oppose their forward motion. During the later part of descents, turtles worked less hard in line with opposing buoyancy forces being reduced. For example, flipper beat frequency declined from about 60–80 beats min−1 at the start of descent to around 25–40 beats min−1 after 30 s of the descent. At the start of ascents the flipper beat frequency was around 30 beats min−1, lower than on descent, and declined as the ascent progressed with often passive gliding for the final few meters to the surface. This pattern of effort during diving appears to apply across a range of marine reptiles, birds and mammals suggesting that graded effort during descent and ascent is an optimum solution to minimising the cost of transport during diving.