Analysis of feedback mechanisms with unknown delay using sparse multivariate autoregressive method

This paper discusses the study of two interacting processes in which a feedback mechanism exists between the processes. The study was motivated by problems such as the circadian oscillation of gene expression where two interacting protein transcriptions form both negative and positive feedback loops with long delays to equilibrium. Traditionally, data of this type could be examined using autoregressive analysis. However, in circadian oscillation the order of an autoregressive model cannot be determined a priori. We propose a sparse multivariate autoregressive method that incorporates mixed linear effects into regression analysis, and uses a forward-backward greedy search algorithm to select nonzero entries in the regression coefficients, the number of which is constrained not to exceed a pre-specified number. A small simulation study provides preliminary evidence of the validity of the method. Besides the circadian oscillation example, an additional example of blood pressure variations using data from an intervention study is used to illustrate the method and the interpretation of the results obtained from the sparse matrix method. These applications demonstrate how sparse representation can be used for handling high dimensional variables that feature dynamic, reciprocal relationships

Gaussian Processes for hearing threshold estimation using Auditory Brainstem Responses

The Auditory Brainstem Response (ABR) plays an important role in diagnosing and managing hearing loss, but can be challenging and time-consuming to measure. Test times are especially long when multiple ABR measurements are needed, e.g., when estimating hearing threshold at a range of frequencies. While many detection methods have been developed to reduce ABR test times, the majority were designed to detect the ABR at a single stimulus level and do not consider correlations in ABR waveforms across levels. These correlations hold valuable information, and can be exploited for more efficient hearing threshold estimation. This was achieved in the current work using a Gaussian Process (GP), i.e., a Bayesian approach method for non-linear regression. The function to estimate with the GP was the ABR's amplitude across stimulus levels, from which hearing threshold was ultimately inferred. Active learning rules were also designed to automatically adjust the stimulus level and efficiently locate hearing threshold. Simulation results show test time reductions of up to $\sim$50% for the GP compared to a sequentially applied Hotelling's T2 test, which does not consider correlations across ABR waveforms. A case study was also included to briefly assess the GP approach in ABR data from an adult volunteer

Envelope frequency following responses are stronger for high-pass than low-pass filtered vowels

Background: To assess hearing in response to speech, the envelope frequency following response (FFR) can be observed at the fundamental frequency of a vowel stimulus, and its harmonics. FFRs are complex non-linear phenomena, which require better understanding for allowing robust inferences on the assessment of hearing and hearing aid fitting. Objectives: To evaluate the effect of stimulus bandwidth on FFR detection rates using filtered vowel stimuli with equal sound levels. Design: FFRs were collected whilst presenting repeated vowels (in consonant-vowel-consonant format) filtered into different bandwidths. Eighty stimuli per word were presented at 70 dB SPL LAeq through insert earphones with an inter-stimulus interval of 1s. Responses were detected using frequency-domain Hotelling’s T2 (HT2) tests for individual multiples of the fundamental frequency (F0) and for combinations of F0 multiples. Study Sample: Eleven native English-speaking subjects with normal hearing thresholds. Results: Average detection rates are highest (69%) with stimuli high-pass filtered >1000 Hz, and significantly lower for low-pass filtered stimuli (40%). Conclusion: High-pass filtered vowels elicit stronger FFRs than low-pass filtered vowels at the same dB SPL LAeq. For testing hearing using band-limited speech, filtering effects (due to hearing loss, hearing aid setting or stimulus choice) on responses must be considered

Use of induced sputum for the diagnosis of influenza and infections in asthma: a comparison of diagnostic techniques

Background: Influenza (Flu) and respiratory syncytial virus (RSV) are important viral pathogens that cause lower respiratory tract infections and severe exacerbations of asthma. Molecular biological techniques are permitting a rapid and accurate diagnosis of infections caused by respiratory pathogens, and have typically been applied to upper respiratory samples. Sputum induction provides an opportunity to directly sample secretions from the lower respiratory tract. Objectives/study design: To determine the role of induced sputum reverse-transcription polymerase chain reaction (RT-PCR) in the detection of respiratory pathogens and compare this with detection using serology and immunofluorescent antigen (IFA) testing, we recruited 49 adults from emergency room with exacerbations of asthma. After a medical assessment and spirometry, sputum was induced using ultrasonically nebulised normal saline. Sputum was assayed using IFA and RT-PCR for flu and RSV. Flu serology was performed acutely and at convalescence, 4-5 weeks later. Results: Influenza A or B was detected in 24% of the samples by PCR, significantly more than the nine cases detected using serology and the one case using IFA (P lt 0.05). RSV was detected in 37% of samples using PCR and 20% by IFA (P lt 0.05). Conclusion: The combination of induced sputum and RT-PCR provides a useful means of detecting respiratory infection. The technique is safe in both adults and children, and RT-PCR is more sensitive than conventional serology and IFA. The improved sensitivity of induced sputum RT-PCR also permits a more rapid diagnosis and the opportunity of early administration of effective treatments

How do Adult Survivors of Childhood Sexual Abuse Experience Formally Delivered Talking Therapy? A Systematic Review

This systematic review explored how adult survivors of childhood sexual abuse experienced non-specific and trauma-focused talking therapies. Following extensive systematic searches of academic databases, 23 qualitative empirical studies were chosen for review. Using a line-by-line thematic synthesis, four analytical themes developed. These themes were: The Therapeutic Process as a Means for Forming Connections, which discusses therapeutic relationships; Developing a Sense of Self through the Therapeutic Processes, identifying stages of developmental recovery; Therapeutic Lights and Black Holes in the Shadows of CSA, reflecting upon how a history of CSA influenced experiences of therapy; and Healing or Harrowing: connecting with others and first time experiences, exploring what was helpful, hindering, and new throughout the therapeutic journey. Findings related to participants developing new options for interpersonal relationships through the experience of authentic trust and the experiential learning of control and choice. Recommendations are discussed in relation to developing therapeutic practice and future research

Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate.

Published onlineResearch Support, Non-U.S. Gov'tHuman activities can create noise pollution and there is increasing international concern about how this may impact wildlife. There is evidence that anthropogenic noise may have detrimental effects on behaviour and physiology in many species but there are few examples of experiments showing how fitness may be directly affected. Here we use a split-brood, counterbalanced, field experiment to investigate the effect of repeated boat-noise playback during early life on the development and survival of a marine invertebrate, the sea hare Stylocheilus striatus at Moorea Island (French Polynesia). We found that exposure to boat-noise playback, compared to ambient-noise playback, reduced successful development of embryos by 21% and additionally increased mortality of recently hatched larvae by 22%. Our work, on an understudied but ecologically and socio-economically important taxon, demonstrates that anthropogenic noise can affect individual fitness. Fitness costs early in life have a fundamental influence on population dynamics and resilience, with potential implications for community structure and function.EPSRCCampus FranceAgence National de RechercheDefraNERC Fellowshi

School is out on noisy reefs: the effect of boat noise on predator learning and survival of juvenile coral reef fishes

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Noise produced by anthropogenic activities is increasing in many marine ecosystems. We investigated the effect of playback of boat noise on fish cognition. We focused on noise from small motorboats, since its occurrence can dominate soundscapes in coastal communities, the number of noise-producing vessels is increasing rapidly and their proximity to marine life has the potential to cause deleterious effects. Cognition-or the ability of individuals to learn and remember information-is crucial, given that most species rely on learning to achieve fitness-promoting tasks, such as finding food, choosing mates and recognizing predators. The caveat with cognition is its latent effect: the individual that fails to learn an important piece of information will live normally until the moment where it needs the information to make a fitness-related decision. Such latent effects can easily be overlooked by traditional risk assessment methods. Here, we conducted three experiments to assess the effect of boat noise playbacks on the ability of fish to learn to recognize predation threats, using a common, conserved learning paradigm. We found that fish that were trained to recognize a novel predator while being exposed to 'reef + boat noise' playbacks failed to subsequently respond to the predator, while their 'reef noise' counterparts responded appropriately. We repeated the training, giving the fish three opportunities to learn three common reef predators, and released the fish in the wild. Those trained in the presence of 'reef + boat noise' playbacks survived 40% less than the 'reef noise' controls over our 72 h monitoring period, a performance equal to that of predator-naive fish. Our last experiment indicated that these results were likely due to failed learning, as opposed to stress effects from the sound exposure. Neither playbacks nor real boat noise affected survival in the absence of predator training. Our results indicate that boat noise has the potential to cause latent effects on learning long after the stressor has gone.Funding for this study was provided by the Natural Sciences and Engineering Research Council of Canada (M.C.O.F., D.P.C.), the Australian Research Council (M.I.M., M.C.O.F., D.P.C., M.G.M.), the ARC Center of Excellence for Coral Reef Studies (M.I.M.) and the UK Natural Environment Research Council (S.D.S.)

Anthropogenic noise increases fish mortality by predation

PublishedNoise-generating human activities affect hearing, communication and movement in terrestrial and aquatic animals, but direct evidence for impacts on survival is rare. We examined effects of motorboat noise on post-settlement survival and physiology of a prey fish species and its performance when exposed to predators. Both playback of motorboat noise and direct disturbance by motorboats elevated metabolic rate in Ambon damselfish (Pomacentrus amboinensis), which when stressed by motorboat noise responded less often and less rapidly to simulated predatory strikes. Prey were captured more readily by their natural predator (dusky dottyback, Pseudochromis fuscus) during exposure to motorboat noise compared with ambient conditions, and more than twice as many prey were consumed by the predator in field experiments when motorboats were passing. Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans.This work was supported by a NERC Knowledge Exchange Fellowship (for S.D.S.), the UK Department for Environment Food and Rural Affairs (S.D.S. and A.N.R.), the ARC Centre of Excellence for Coral Reef Studies (M.I.M; EI140100117) and an EPSRC studentship (S.L.N.). NERC KE Fellowship (S.D.S.; NE/J500616/2

Experiences of Therapeutic Relationships on Hospital Wards, Dissociation and Making Connections

An interpretative phenomenological analysis sought to explore how people reporting moderate to high levels of dissociation experienced relationships with multidisciplinary hospital ward staff. Three superordinate themes were developed. Firstly, the theme Multiple Me and Multiple Them explores the instability experienced by the participants as they managed their dissociative experiences alongside many inconsistencies. Secondly, Recognising, Meeting or Neglecting Interpersonal and Care Needs, reflects upon participants’ needs within therapeutic relationships. Thirdly, Between the Needs of the Internal System: navigating between “better on my own” and “someone to talk to”, discusses the confusion and understanding around dissociation and the importance of working with parts, not around them. Findings suggested the current culture of some hospital wards directly influenced participants’ distress, which could lead to further dissociation as a means of coping with perceived threats. Reflections upon relational complexities and developing ward-based treatment are discussed

Motorboat noise impacts parental behaviour and offspring survival in a reef fish

This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this record.Anthropogenic noise is a pollutant of international concern, with mounting evidence of disturbance and impacts on animal behaviour and physiology. However, empirical studies measuring survival consequences are rare. We use a field experiment to investigate how repeated motorboat-noise playback affects parental behaviour and offspring survival in the spiny chromis (Acanthochromis polyacanthus), a brooding coral reef fish. Repeated observations were made for 12 days at 38 natural nests with broods of young. Exposure to motorboat-noise playback compared to ambient-sound playback increased defensive acts, and reduced both feeding and offspring interactions by brood-guarding males. Anthropogenic noise did not affect the growth of developing offspring, but reduced the likelihood of offspring survival; while offspring survived at all 19 nests exposed to ambient-sound playback, six of the 19 nests exposed to motorboat-noise playback suffered complete brood mortality. Our study, providing field-based experimental evidence of the consequences of anthropogenic noise, suggests potential fitness consequences of this global pollutant.This work was supported by a NERC Knowledge Exchange Fellowship (for S.D.S.; NE/J500616/2), the UK Department for Environment Food and Rural Affairs (S.D.S. and A.N.R.; ME5207), funds from ARC Centre of Excellence for Coral Reef Studies (M.I.M; EI140100117), an EPSRC studentship and Subacoustech (S.L.N.)