34 resultados para Sound Duration
Resumo:
The precise role of cell cycle-dependent molecules in controlling the switch from cardiac myocyte hyperplasia to hypertrophy remains to be determined. We report that loss of p27(KIP1) in the mouse results in a significant increase in heart size and in the total number of cardiac myocytes. In comparison to p27(KIP1)+/+ myocytes, the percentage of neonatal p27(KIP1)-/- myocytes in S phase was increased significantly, concomitant with a significant decrease in the percentage of G(0)/G(1) cells. The expressions of proliferating cell nuclear antigen, G(1)/S and G(2)/M phase-acting cyclins, and cyclin-dependent kinases (CDKs) were upregulated significantly in ventricular tissue obtained from early neonatal p27(KIP1)-/- mice, concomitant with a substantial decrease in the expressions of G(1) phase-acting cyclins and CDKs. Furthermore, mRNA expressions of the embryonic genes atrial natriuretic factor and alpha-skeletal actin were detectable at significant levels in neonatal and adult p27(KIP1)-/- mouse hearts but were undetectable in p27(KIP1)+/+ hearts. In addition, loss of p27(KIP1) was not compensated for by the upregulation of other CDK inhibitors. Thus, the loss of p27(KIP1) results in prolonged proliferation of the mouse cardiac myocyte and perturbation of myocyte hypertrophy.
Resumo:
This paper reports the pitch range and vowel duration data from a group of children with Williams syndrome (WS) in comparison with a group of typically developing children matched for chronological age (CA) and a group matched for receptive language abilities (LA). It is found that the speech of the WS group has a greater pitch range and that vowels tend to be longer in duration than in the speech of the typically developing children. These findings are in line with the impressionistic results reported by Reilly, Klima and Bellugi [17].
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Infrared optical-multilayer filters and materials were exposed to the space environment of low Earth for a period of nearly six years on the NASA Long Duration Exposure Facility (LDEF) mission. This report describes the effects of that environment on the physical and optical properties of filters and materials used in an experiment designed by the University of reading Infrared multilayer Laboratory. Results of the experiment comprise IR processed spectra both before (1983), and after (1990) exposure, in conjunction with unexposed control samples.
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BACKGROUND: Humans from an early age look longer at preferred stimuli, and also typically look longer at facial expressions of emotion, particularly happy faces. Atypical gaze patterns towards social stimuli are common in Autism Spectrum Conditions (ASC). However, it is unknown if gaze fixation patterns have any genetic basis. In this study, we tested if variations in the cannabinoid receptor 1 (CNR1) gene are associated with gaze duration towards happy faces. This gene was selected because CNR1 is a key component of the endocannabinoid system, involved in processing reward, and in our previous fMRI study we found variations in CNR1 modulates the striatal response to happy (but not disgust) faces. The striatum is involved in guiding gaze to rewarding aspects of a visual scene. We aimed to validate and extend this result in another sample using a different technique (gaze tracking). METHODS: 30 volunteers (13 males, 17 females) from the general population observed dynamic emotion expressions on a screen while their eye movements were recorded. They were genotyped for the identical four SNPs in the CNR1 gene tested in our earlier fMRI study. RESULTS: Two SNPs (rs806377 and rs806380) were associated with differential gaze duration for happy (but not disgust) faces. Importantly, the allelic groups associated with greater striatal response to happy faces in the fMRI study were associated with longer gaze duration for happy faces. CONCLUSIONS: These results suggest CNR1 variations modulate striatal function that underlies the perception of signals of social reward such as happy faces. This suggests CNR1 is a key element in the molecular architecture of perception of certain basic emotions. This may have implications for understanding neurodevelopmental conditions marked by atypical eye contact and facial emotion processing, such as ASC.
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In this paper we derive novel approximations to trapped waves in a two-dimensional acoustic waveguide whose walls vary slowly along the guide, and at which either Dirichlet (sound-soft) or Neumann (sound-hard) conditions are imposed. The guide contains a single smoothly bulging region of arbitrary amplitude, but is otherwise straight, and the modes are trapped within this localised increase in width. Using a similar approach to that in Rienstra (2003), a WKBJ-type expansion yields an approximate expression for the modes which can be present, which display either propagating or evanescent behaviour; matched asymptotic expansions are then used to derive connection formulae which bridge the gap across the cut-off between propagating and evanescent solutions in a tapering waveguide. A uniform expansion is then determined, and it is shown that appropriate zeros of this expansion correspond to trapped mode wavenumbers; the trapped modes themselves are then approximated by the uniform expansion. Numerical results determined via a standard iterative method are then compared to results of the full linear problem calculated using a spectral method, and the two are shown to be in excellent agreement, even when $\epsilon$, the parameter characterising the slow variations of the guide’s walls, is relatively large.
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Records of Atlantic basin tropical cyclones (TCs) since the late nineteenth century indicate a very large upward trend in storm frequency. This increase in documented TCs has been previously interpreted as resulting from anthropogenic climate change. However, improvements in observing and recording practices provide an alternative interpretation for these changes: recent studies suggest that the number of potentially missed TCs is sufficient to explain a large part of the recorded increase in TC counts. This study explores the influence of another factor—TC duration—on observed changes in TC frequency, using a widely used Atlantic hurricane database (HURDAT). It is found that the occurrence of short-lived storms (duration of 2 days or less) in the database has increased dramatically, from less than one per year in the late nineteenth–early twentieth century to about five per year since about 2000, while medium- to long-lived storms have increased little, if at all. Thus, the previously documented increase in total TC frequency since the late nineteenth century in the database is primarily due to an increase in very short-lived TCs. The authors also undertake a sampling study based upon the distribution of ship observations, which provides quantitative estimates of the frequency of missed TCs, focusing just on the moderate to long-lived systems with durations exceeding 2 days in the raw HURDAT. Upon adding the estimated numbers of missed TCs, the time series of moderate to long-lived Atlantic TCs show substantial multidecadal variability, but neither time series exhibits a significant trend since the late nineteenth century, with a nominal decrease in the adjusted time series. Thus, to understand the source of the century-scale increase in Atlantic TC counts in HURDAT, one must explain the relatively monotonic increase in very short-duration storms since the late nineteenth century. While it is possible that the recorded increase in short-duration TCs represents a real climate signal, the authors consider that it is more plausible that the increase arises primarily from improvements in the quantity and quality of observations, along with enhanced interpretation techniques. These have allowed National Hurricane Center forecasters to better monitor and detect initial TC formation, and thus incorporate increasing numbers of very short-lived systems into the TC database.
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The Retrieval-Induced Forgetting (RIF) paradigm includes three phases: (a) study/encoding of category exemplars, (b) practicing retrieval of a sub-set of those category exemplars, and (c) recall of all exemplars. At the final recall phase, recall of items that belong to the same categories as those items that undergo retrieval-practice, but that do not undergo retrieval-practice, is impaired. The received view is that this is because retrieval of target category-exemplars (e.g., ‘Tiger’ in the category Four-legged animal) requires inhibition of non-target category-exemplars (e.g., ‘Dog’ and ‘Lion’) that compete for retrieval. Here, we used the RIF paradigm to investigate whether ignoring auditory items during the retrieval-practice phase modulates the inhibitory process. In two experiments, RIF was present when retrieval-practice was conducted in quiet and when conducted in the presence of spoken words that belonged to a category other than that of the items that were targets for retrieval-practice. In contrast, RIF was abolished when words that either were identical to the retrieval-practice words or were only semantically related to the retrieval-practice words were presented as background speech. The results suggest that the act of ignoring speech can reduce inhibition of the non-practiced category-exemplars, thereby eliminating RIF, but only when the spoken words are competitors for retrieval (i.e., belong to the same semantic category as the to-be-retrieved items).
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'The Prophetic Sound: a day and night of noise cabaret' is the first event hosted by Agency of Noise. This all day event brought together artists and academics whose subject of focus is noise (in creative practice). Artists from across the UK were invited to consider a future post-digital era in which everything with a microchip has malfunctioned, as a thought exercise and starting point for response through sound. In response to Jacques Attali’s claim that music is prophecy, The Prophetic Sound asks us to consider if noise can communicate in an unbridled, unfiltered, way that is somehow not culturally coded -before it becomes sound that is recognised, refined, manipulated and exploited for musical or other cultured purpose. Featuring students from Reading, Brighton, LCC and Goldsmiths alongside more established artists and academics from across the UK, this event brings into focus locations where pattern, timbre, pitch, organisation and sequencing of sounds become distinguishable from noise and asks us to consider, through diversion within such locations, new origins for future communication systems. The Prophetic Sound included talks, films, presentations and performances from: Ryo Ikeshiro / Inigo Wilkins / Neal Spowage / Dane Sutherland / Poulomi Desai / Benedict Drew / AAS / Polly Fibre / Steven Dickie As part of The Prophetic Sound, POLLYFIBRE (Ellison, C.) performed LIVE RECORDING with Amplified Scissors. This industrial activity by POLLYFIBRE short-circuits the complicated chain that is music production. The distinctive roles of consumer, producer, composer, and performer collapse in a series of live ‘cuts’ where vinyl discs are produced with amplified scissors. Production happens through action and action becomes production. A limited edition of 9 flexi discs were produced and available for special collectors at the event.
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Recent national developments in the teaching of literacy in the early years in the UK mean that teachers need to have explicit fluent knowledge of the sound structure of the language and its relationship to orthography in order to teach reading effectively. In this study, a group of 38 graduate trainee primary teachers were given a pencil and paper test of phonological awareness as part of a course on teaching literacy. Results from the pencil and paper test were used as the basis of teaching about the sound structure of words. The test was repeated six months later. The results showed that they did not use a consistent system for segmenting words into component sounds. Though there was substantial improvement on second testing, many trainees still did not show evidence that they had yet developed sufficient insights into the sound structure of words to be able to teach children about phonemes with certainty. It is argued that student teachers need substantial explicit training and practice in manipulating the sound structure of words to enable them to teach this aspect of language confidently.
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Recent studies have shown that the haemodynamic responses to brief (<2 secs) stimuli can be well characterised as a linear convolution of neural activity with a suitable haemodynamic impulse response. In this paper, we show that the linear convolution model cannot predict measurements of blood flow responses to stimuli of longer duration (>2 secs), regardless of the impulse response function chosen. Modifying the linear convolution scheme to a nonlinear convolution scheme was found to provide a good prediction of the observed data. Whereas several studies have found a nonlinear coupling between stimulus input and blood flow responses, the current modelling scheme uses neural activity as an input, and thus implies nonlinearity in the coupling between neural activity and blood flow responses. Neural activity was assessed by current source density analysis of depth-resolved evoked field potentials, while blood flow responses were measured using laser Doppler flowmetry. All measurements were made in rat whisker barrel cortex after electrical stimulation of the whisker pad for 1 to 16 secs at 5 Hz and 1.2 mA (individual pulse width 0.3 ms).
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Terrorism can strengthen or weaken electoral support for ruling governments. We show in a simple model of coalition formation that, regardless of the direction of a public opinion shock, the impact of terrorism on cabinet duration is ambiguous. However, in an analysis of a data set including 2,400 cabinets in over 150 countries in the period 1970–2002, we find that terrorism, on average, shortens cabinet duration. This result is robust for a range of alternative terror measures and is present in both democratic as well as autocratic political regimes.