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Speech referenced dynamic compression limiting: improving loudness comfort and acoustic safety
No full textTheoretical thesis.Bibliography: pages 299-314.This thesis presents the research, development and evaluation associated with a novel method of improving listening comfort and acoustic safety for people listening primarily to speech produced by electronic devices such as headsets, telephones, headphones, hearing aids, cochlear implants, level-dependent hearing protectors and public address systems. The method involves a novel technique of amplitude limiting audio signals that convey speech. Time-varying, frequency-specific levels of speech generate a set of time-varying speech reference levels. The method limits the level of the audio to these speech reference levels and hence is called speech referenced limiting (SRL). In principle, SRL provides the greatest limiting of noise for the least limiting of speech, making it arguably the optimal method for limiting noise in speech systems. Two schemes based on the method were developed, the SRL MKI and the SRL MKII schemes. The latter scheme was far superior, with the ability to estimate the speech loudness and power from frequency regions where speech was dominant, while ignoring frequency regions where it was not. It contained a novel method of determining the amount of additional control needed to correct for the loudness summation of noises with a bandwidth exceeding that of speech, as well as providing fast speech referenced control over the power of abrupt sounds while introducing only a very short delay.Subjective evaluation of the SRL MKI and SRL MKII schemes conducted in the laboratory confirmed large reductions in noise loudness and preservation of speech quality. It was hypothesised that the SRL MKII scheme would provide the greatest reduction in the excess loudness of an audio signal compared with the loudness of the preceding speech conveyed by the audio signal for the least reduction in the speech loudness and quality. Using stimuli typical of those experienced in the three main intended applications (hearing aids, level-dependent hearing protectors and telephone headsets), this hypothesis held true and noise control was shown to be far superior to a conventional fixed-reference limiter while speech loudness and quality were maintained.1. Introduction -- 2. Psychoacoustic factors -- 3. Acoustic shock and related factors -- 4. Sound level control methods -- 5. Speech referenced limiting - in theory -- 6. SRL MKI scheme -- 7. Subjective evaluation of SRL MKI -- 8. SRL MKII scheme -- 9. Subjective evaluation of SRL MKII -- 10. Conclusion.Mode of access: World wide web1 online resource (xxii, 314 pages) graphs, table
Contested territories
No full textPurpose: Increasing government regulation of educational practice with public accountability through a national curriculum and external testing, the establishment of professional teaching standards and associated teacher accreditation requirements are strong forces in contemporary Australian education. This paper aims to identify and examine some of the current governmental policies and the associated institutionalised requirements for initial teacher education within this particular context. Design/methodology/approach: It focuses particularly on preservice English teachers, and in addressing these issues, there is an exploration of the contested territory of the subject English, the key factors affecting initial teacher education students and the effects of professional standards on educators. Findings: It is argued that there is a need for a much broader vision of educational purpose, a richer construction of subject English than is defined by the testing of traditional literacy skills and productivity outcomes, with a greater empowerment of teachers whose achievements are increasingly limited by narrow accountability measures. Originality/value: Formal accreditation demands appear to constrain the various multimodal practices and creative, collaborative pedagogies that enhance educational experiences in the twenty-first century. The challenge ahead for educators is to find a balance between the contemporary pressures of a global society, external expectations, professional aspirations and personal values.19 page(s
Microglia PACAP and glutamate : friends or foes in seizure-induced autonomic dysfunction and SUDEP?
No full textSeizure-induced cardiorespiratory autonomic dysfunction is a major cause of sudden unexpected death in epilepsy (SUDEP), and the underlying mechanism is unclear. Seizures lead to increased synthesis, and release of glutamate, pituitary adenylate cyclase activating polypeptide (PACAP), and other neurotransmitters, and cause extensive activation of microglia at multiple regions in the brain including central autonomic cardiorespiratory brainstem nuclei. Glutamate contributes to neurodegeneration, and inflammation in epilepsy. PACAP has neuroprotective, and anti-inflammatory properties, whereas microglia are key players in inflammatory responses in CNS. Seizure-induced increase in PACAP is neuroprotective. PACAP produces neuroprotective effects acting on microglial PAC1 and VPAC1 receptors. Microglia also express glutamate transporters, and their expression can be increased by PACAP in response to harmful or stressful situations such as seizures. Here we discuss the mechanism of autonomic cardiorespiratory dysfunction in seizure, and the role of PACAP, glutamate and microglia in regulating cardiorespiratory brainstem neurons in their physiological state that could provide future therapeutic options for SUDEP.12 page(s
The Changing experiences of primary teachers : responding to scenarios involving diverse sexualities
No full textSex education and diverse sexualities are controversial topics within the primary school arena. Concepts of childhood innocence have influenced sex education curriculum, policy development and teaching practices within schools. However, research shows that primary school-aged students are aware of and talk about sexualities. The aim of this research is to reveal the pedagogical experiences of primary school teachers in relation to scenarios inclusive of diverse sexualities. Social constructionist theories of pedagogy and phenomenographic methods are used to provide a detailed analysis of the ways in which primary teacher participants conceptualise their encounters with students who introduce concepts of diverse sexualities. This research reveals that primary students ask questions about diverse sexualities, they use homophobic expressions (often as a daily occurrence), they sometimes reveal homosexual feelings to teachers, some have same-sex parents and some are being raised with knowledge of diverse sexualities. Without comprehensive policy and curriculum support, and appropriate professional learning for teachers, teachers are unable to make well-informed pedagogical decisions that promote inclusive education.15 page(s
Drivers and semantic properties of intellectual capital information in sell-side analysts’ reports
No full textPurpose: This paper aims to understand the potential usefulness of sell-side analysts’ investment recommendation reports as a medium for communicating intellectual capital (IC) information. It explores the manner in which analyst reports supply IC information and the types of companies in relation to which analyst reports supply most IC information. Design/methodology/approach: A content analysis of 64 initiating coverage analyst reports written on Australian companies is performed. The content analysis focuses on three semantic properties of IC disclosures: format (i.e. discursive, numerical-non-monetary, numerical-monetary and visual), news-tenor (i.e. positive, neutral and negative) and time-orientation (i.e. forward-looking, non-time-specific and past-oriented). The paper investigates whether analyst reports contain more IC information on companies providing less IC information through their own channels. For this, the authors test the hypothesised relationship between the extent of IC information and the IC intensity of the analysed company’s sector and the systematic risk of the company. Findings: IC information in analyst reports is more discursive than numerical, not significantly more forward-looking in general and balanced between negative or neutral and positive attributions (except for information on company management). However, compared to the semantic properties of corporate reporting media, analyst reports in this study communicate IC information in a manner arguably more useful to investors. A company’s systematic risk and sector in which the company operates are associated with the extent of IC information in analyst reports. The findings indicate that analysts’ contribution as an IC information provider is greatest for companies providing less IC information directly to the public. Practical implications: The results have implications for policymakers contemplating reforming non-financial reporting regulation and ensuring a level playing field for investors and companies when determining corporate IC disclosure strategy and strategies for investor relations. Originality/value: This is the first study to explore semantic properties and drivers of IC information in analysts’ initiating coverage reports. This paper highlights the importance of analyst reports as a medium for communicating IC information that could complement corporate communication media.38 page(s
Measurement of Rayleigh wave ellipticity and its application to the joint inversion of high-resolution S wave velocity structure beneath northeast China
No full textWe present a new 3-D S wave velocity model of the northeast (NE) China from the joint inversion of the Rayleigh wave ellipticity and phase velocity at 8–40 s periods. Rayleigh wave ellipticity, or Rayleigh wave Z/H (vertical to horizontal) amplitude ratio, is extracted from both earthquake (10–40 s) and ambient noise data (8–25 s) recorded by the NorthEast China Extended SeiSmic Array with 127 stations. The estimated Z/H ratios from earthquake and ambient noise data show good consistency within the overlapped periods. The observed Z/H ratio shows a good spatial correlation with surface geology and is systematically low within the basins. We jointly invert the measured Z/H ratio and phase velocity dispersion data to obtain a refined 3-D S wave velocity model beneath the NE China. At shallow depth, the 3-D model is featured by strong low-velocity anomalies that are spatially well correlated with the Songliao, Sanjiang, and Erlian basins. The low-velocity anomaly beneath the Songliao basin extends to ~ 2–3 km deep in the south and ~5–6 km in the north. At lower crustal depths, we find a significant low-velocity anomaly beneath the Great Xing'an range that extends to the upper mantle in the south. Overall, the deep structures of the 3-D model are consistent with previous models, but the shallow structures show a much better spatial correlation with tectonic terranes. The difference in sedimentary structure between the southern and northern Songliao basin is likely caused by a mantle upwelling associated with the Pacific subduction.17 page(s
Sexual segregation in Habitat use is smaller than expected in a highly dimorphic marine predator, the southern sea lion
No full textSexual segregation in habitat use is widely reported in many taxa and can profoundly influence the distribution and behaviour of animals. However, our knowledge of the mechanisms driving sexual segregation is still in its infancy (particularly in marine taxa) and the influence of extrinsic factors in mediating the expression of sex differences in foraging behaviour is underdeveloped. Here, we combine data from biologging tags, with stable isotope analysis of vibrissae, to assess sexual segregation in southern sea lions (SSL) (Otaria flavescens) breeding at the Falkland Islands in the South Atlantic. We found evidence to support segregation, most notably in δ¹³C and δ¹⁵N values. However, in spite of extreme sexual size dimorphism and differing constraints related to female-only parental care, adult male and adult female SSL overlapped considerably in isotopic niches and foraging area, and shared similar foraging trip characteristics (such as distance and duration). This is in contrast to SSL breeding in Argentina, where prior studies report sexual differences in foraging locations and foraging trip characteristics. We posit that sexual segregation in SSL is influenced by habitat availability (defined here as the width of the Patagonian Shelf) and individual foraging preferences, rather than commonly invoked individual-based limiting factors per se.11 page(s
The Effect of blocked, random and mixed practice schedules on speech motor learning of tongue twisters in unimpaired speakers
No full textThere are few investigations comparing practice schedules in speech motor learning, despite certain schedules being recommended for the clinical treatment of speech motor disorders. This study compared effects of random, blocked and mixed practice on tongue twister accuracy in unimpaired speakers. We hypothesized that blocked practice would benefit acquisition of learning, but that random practice and mixed blocked-then-random practice would yield superior retention of learning. We found that the random and blocked-random practice schedules yielded superior accuracy at the end of the acquisition phase of learning and at a 1-week retention test. Exploratory post hoc analyses raised the possibility that the retention effects were most evident when tongue twisters were elicited in a random schedule. Theoretical accounts of these results are discussed.30 page(s
Reproduction and dispersal pattern of egg parasitoids of Riptortus pedestris (Hemiptera : Alydidae) after installing pheromone traps plus non-viable host eggs
No full textThe aggregation pheromone of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) has a kairomonal effect on its egg parasitoids. The addition of non-viable R. pedestris eggs to aggregation pheromone traps was suggested as a means to enhance reproduction of parasitoids attracted to pheromone traps and was found to enhance field parasitism. In this study, we tested if the eggs added to traps are indeed used by parasitoids for their reproduction. Spatial distributions of egg parasitism were assessed in a barley and a sesame field where non-viable host eggs were installed at four distances (8, 16, 24, and 32 m) in two directions from the aggregation pheromone traps placed in the center of each field. While field parasitism increased significantly over time, it decreased with distance from traps. Higher egg parasitism was found up to 16 m from the point of release in both barley and sesame fields. To compare temporal changes in parasitism, traps were also installed in another barley and another sesame field without adding host eggs. From regression slope comparisons, significant differences were found only in the sesame fields, where the parasitism rate on the last sampling date in the egg-released field was higher than the comparison field by 80%. A higher male proportion was found near the trap installation point only for Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae) in the sesame field. These findings suggest that supplemental host eggs in traps enhance field parasitism by increasing the reproduction and dispersion of field populations of parasitoids.5 page(s
Rivalry effects and unbalanced schedule optimisation in the Australian football league
No full textLike many professional sports leagues, the Australian Football League (AFL) operates an unbalanced schedule in which each team plays other teams an unequal number of times (once or twice) each season. This has led the AFL purposefully to schedule certain matches to be repeated each season with the remaining fixtures mostly randomly allocated. We explore the efficacy of this policy by estimating a fixed (rivalry) effects hedonic demand model for within-season AFL matches. Estimated rivalry effects are imputed into a binary integer program minimisation that provides an optimal profile of rematches against which we consider recent historic scheduling behaviour. As expected, rivalry effects are greatest for the large-market Melbourne ‘troika’ teams, which provides partial support for the AFL’s maintained policy. However, there exists scope for increasing aggregate attendance in the unbalanced part of the season by further attention to selection of rematches. We also observe some decline in interest of the second within-season meetings of popular troika teams and a rise in popularity of the intrastate derbies. Finally, we compare our results to alternative scheduling arrangements for the unbalanced part of the season.27 page(s