Exploiting correlogram structure for robust speech recognition with multiple speech sources

This paper addresses the problem of separating and recognising speech in a monaural acoustic mixture with the presence of competing speech sources. The proposed system treats sound source separation and speech recognition as tightly coupled processes. In the first stage sound source separation is performed in the correlogram domain. For periodic sounds, the correlogram exhibits symmetric tree-like structures whose stems are located on the delay that corresponds to multiple pitch periods. These pitch-related structures are exploited in the study to group spectral components at each time frame. Local pitch estimates are then computed for each spectral group and are used to form simultaneous pitch tracks for temporal integration. These processes segregate a spectral representation of the acoustic mixture into several time-frequency regions such that the energy in each region is likely to have originated from a single periodic sound source. The identified time-frequency regions, together with the spectral representation, are employed by a `speech fragment decoder' which employs `missing data' techniques with clean speech models to simultaneously search for the acoustic evidence that best matches model sequences. The paper presents evaluations based on artificially mixed simultaneous speech utterances. A coherence-measuring experiment is first reported which quantifies the consistency of the identified fragments with a single source. The system is then evaluated in a speech recognition task and compared to a conventional fragment generation approach. Results show that the proposed system produces more coherent fragments over different conditions, which results in significantly better recognition accuracy

Visualising and quantifying 'excess deaths' in Scotland compared with the rest of the UK and the rest of Western Europe

BACKGROUND: Scotland has higher mortality rates than the rest of Western Europe (rWE), with more cardiovascular disease and cancer among older adults; and alcohol-related and drug-related deaths, suicide and violence among younger adults. METHODS: We obtained sex, age-specific and year-specific all-cause mortality rates for Scotland and other populations, and explored differences in mortality both visually and numerically. RESULTS: Scotland's age-specific mortality was higher than the rest of the UK (rUK) since 1950, and has increased. Between the 1950s and 2000s, 'excess deaths' by age 80 per 100 000 population associated with living in Scotland grew from 4341 to 7203 compared with rUK, and from 4132 to 8828 compared with rWE. UK-wide mortality risk compared with rWE also increased, from 240 'excess deaths' in the 1950s to 2320 in the 2000s. Cohorts born in the 1940s and 1950s throughout the UK including Scotland had lower mortality risk than comparable rWE populations, especially for males. Mortality rates were higher in Scotland than rUK and rWE among younger adults from the 1990s onwards suggesting an age-period interaction. CONCLUSIONS: Worsening mortality among young adults in the past 30 years reversed a relative advantage evident for those born between 1950 and 1960. Compared with rWE, Scotland and rUK have followed similar trends but Scotland has started from a worse position and had worse working age-period effects in the 1990s and 2000s

The affordance of place in developing place-responsive science teaching pedagogy : reflections from pre-service teachers

Despite being increasingly popular within broader educational discourse, place-responsive pedagogy is less apparent in science teacher education. This paper investigates the perspectives of pre-service teachers in a science education course informed by place-responsive pedagogy in a Bachelor of Education (primary) program at an Australian regional university. The place-based study belongs to longitudinal research that examined the impact of the modified science course hallmarked by university–school partnerships and science lessons conducted by pre-service teachers with children from rural and regional schools in Gippsland, Victoria in a wetland and school ground setting. The study and science course were framed by a place pedagogy framework. Using this framework, we examine how pre-service teachers view and understand the affordance of places for teaching science. The study employed a document analysis of coursework essays as well as follow-up semi-structured interviews with two pre-service teacher cohorts (wetland and school ground). Findings indicate that pre-service teacher’s exposure to place-responsive frameworks helped build their awareness about the affordance of place for science teaching. Challenges associated with taking science beyond the conventional classroom are also identified and discussed. © 2021 Association for Science Teacher Education

Learning to teach in place : transforming pre-service teacher perceptions of science teaching through place pedagogies

Although teaching science outdoors is well established in global circles, its pedagogical value in Australia is less understood. This paper addresses this gap through its investigation of outdoor science teaching in a science method course in a teacher education program at an Australian regional university. As part of their coursework, pre-service teachers designed and delivered science lessons to primary school-aged children in small teaching groups in a wetland setting and wrote reflective essays about the experience. Data collection methods included document analysis of the essays as well as follow-up semi-structured interviews with pre-service teachers. Findings suggest that the outdoor science teaching experience improved pre-service teachers' general science teaching skills, and significantly contributed to their capacity to teach science outdoors. Considerations regarding how teacher education curriculum and pedagogy can be reconfigured to better equip graduating teachers with the relevant science skills, knowledge and confidence are discussed. © 2021 Social Science Press. All rights reserved

A longitudinal study on a place-based school-university partnership : listening to the voices of in-service teachers

This paper reports on a longitudinal place-based study by two Australian teacher educators investigating their three-year science-based school-university partnership. The study examined key benefits, challenges, and tensions within the partnership. Data collection was drawn from focus group interviews with in-service teachers across each partnership year. While findings portray the partnership as a catalyst for increased science learning opportunities for school students, teaching opportunities for pre-service teachers, and new in-service teacher roles and responsibilities, the study highlights the evolving nature of partnership development, including the need for continuous negotiation of labor division and stakeholder expectations. © 2023 The Author

Scald risk in social housing can be reduced through thermostatic control system without increasing Legionella risk: a cluster randomised trial.

OBJECTIVE: To quantify the effects of a thermostatic control system in social (public) housing on the prevalence of dangerous (>60°C) water temperatures and on fuel consumption. DESIGN: Pair-matched double-blind cluster randomised controlled trial. SETTING: Social housing in a deprived inner-London borough. PARTICIPANTS: 150 households recruited as clusters from 22 social housing estates. Four small estates were combined into two clusters (resulting in a total of 10 pairs of clusters). INTERVENTION: Social housing estate boiler houses were randomised to a thermostatic control sterilisation programme (heating water to 65°C during 00:00-06:00 h and to 50°C from 06:00 to 00:00 h daily) or to standard control (constant temperature 65°C). MAIN OUTCOME MEASURES: Water temperature over 60°C ('dangerous') after running taps for 1 min and daily fuel consumption (cubic feet of gas). RESULTS: 10 clusters (80 households) were allocated to the sterilisation programme and 10 clusters (70 households) to control, of which 73 and 67 households, respectively, were analysed. Prevalence of dangerous (>60°C) hot water temperatures at 1 min was significantly reduced with the sterilisation programme (mean of cluster prevalence 1% in sterilisation programme group vs 34% in control group; absolute difference 33%, 95% CI 12% to 54%; p=0.006). Prevalence of high (>55°C) hot water temperatures at 1 min was significantly reduced (31% sterilisation vs 59% control; absolute difference 28%, 95% CI 9% to 47%; p=0.009). Gas consumption per day reduced more in the control group than in the sterilisation programme group, although not statistically significantly (p=0.125). CONCLUSIONS: The thermostatic control with daily sterilisation was effective in capping hot water temperatures and therefore reduced scald risk. Although expected to save energy, fuel consumption was increased relative to the control group. Trial registration ClinicalTrials.gov ID: NCT00874692

Learning to Teach in Place: Transforming Pre-service Teacher Perceptions of Science Teaching Through Place Pedagogies

Although teaching science outdoors is well established in global circles, its pedagogical value in Australia is less understood. This paper addresses this gap through its investigation of outdoor science teaching in a science method course in a teacher education program at an Australian regional university. As part of their coursework, pre-service teachers designed and delivered science lessons to primary school-aged children in small teaching groups in a wetland setting and wrote reflective essays about the experience. Data collection methods included document analysis of the essays as well as follow-up semi-structured interviews with pre-service teachers. Findings suggest that the outdoor science teaching experience improved pre-service teachers’ general science teaching skills, and significantly contributed to their capacity to teach science outdoors. Considerations regarding how teacher education curriculum and pedagogy can be reconfigured to better equip graduating teachers with the relevant science skills, knowledge and confidence are discussed

Perturbation of eigenvalues of matrix pencils and optimal assignment problem

We consider a matrix pencil whose coefficients depend on a positive parameter $\epsilon$, and have asymptotic equivalents of the form $a\epsilon^A$ when $\epsilon$ goes to zero, where the leading coefficient $a$ is complex, and the leading exponent $A$ is real. We show that the asymptotic equivalent of every eigenvalue of the pencil can be determined generically from the asymptotic equivalents of the coefficients of the pencil. The generic leading exponents of the eigenvalues are the "eigenvalues" of a min-plus matrix pencil. The leading coefficients of the eigenvalues are the eigenvalues of auxiliary matrix pencils, constructed from certain optimal assignment problems.Comment: 8 page

Historical Analysis Exposes Catastrophic Seagrass Loss for the United Kingdom

The spatial extent of seagrass is poorly mapped, and knowledge of historical loss is limited. Here, we collated empirical and qualitative data using systematic review methods to provide unique analysis on seagrass occurrence and loss in the United Kingdom. We document 8,493 ha of recently mapped seagrass in the United Kingdom since 1998. This equates to an estimated 0.9 Mt of carbon, which, in the current carbon market represents about £22 million. Using simple models to estimate seagrass declines triangulated against habitat suitability models, we provide evidence of catastrophic seagrass loss; at least 44% of United Kingdom’s seagrasses have been lost since 1936, 39% since the 1980’s. However, losses over longer time spans may be as high as 92%. Based on these estimates, historical seagrass meadows could have stored 11.5 Mt of carbon and supported approximately 400 million fish. Our results demonstrate the vast scale of losses and highlight the opportunities to restore seagrass to support a range of ecosystems services