Effects of Age and Noise Exposure on Proxy Measures of Cochlear Synaptopathy

Although there is strong histological evidence for age-related synaptopathy in humans, evidence for the existence of noise-induced cochlear synaptopathy in humans is inconclusive. Here, we sought to evaluate the relative contributions of age and noise exposure to cochlear synaptopathy using a series of electrophysiological and behavioral measures. We extended an existing cohort by including 33 adults in the age range 37 to 60, resulting in a total of 156 participants, with the additional older participants resulting in a weakening of the correlation between lifetime noise exposure and age. We used six independent regression models (corrected for multiple comparisons), in which age, lifetime noise exposure, and high-frequency audiometric thresholds were used to predict measures of synaptopathy, with a focus on differential measures. The models for auditory brainstem responses, envelope-following responses, interaural phase discrimination, and the co-ordinate response measure of speech perception were not statistically significant. However, both age and noise exposure were significant predictors of performance on the digit triplet test of speech perception in noise, with greater noise exposure (unexpectedly) predicting better performance in the 80 dB sound pressure level (SPL) condition and greater age predicting better performance in the 40 dB SPL condition. Amplitude modulation detection thresholds were also significantly predicted by age, with older listeners performing better than younger listeners at 80 dB SPL. Overall, the results are inconsistent with the predicted effects of synaptopathy

Investigating the effects of noise exposure on self-report, behavioral and electrophysiological indices of hearing damage in musicians with normal audiometric thresholds

Musicians are at risk of hearing loss due to prolonged noise exposure, but they may also be at risk of early sub-clinical hearing damage, such as cochlear synaptopathy. In the current study, we investigated the effects of noise exposure on electrophysiological, behavioral and self-report correlates of hearing damage in young adult (age range = 18–27 years) musicians and non-musicians with normal audiometric thresholds. Early-career musicians (n = 76) and non-musicians (n = 47) completed a test battery including the Noise Exposure Structured Interview, pure-tone audiometry (PTA; 0.25–8 kHz), extended high-frequency (EHF; 12 and 16 kHz) thresholds, otoacoustic emissions (OAEs), auditory brainstem responses (ABRs), speech perception in noise (SPiN), and self-reported tinnitus, hyperacusis and hearing in noise difficulties. Total lifetime noise exposure was similar between musicians and non-musicians, the majority of which could be accounted for by recreational activities. Musicians showed significantly greater ABR wave I/V ratios than non-musicians and were also more likely to report experience of - and/or more severe - tinnitus, hyperacusis and hearing in noise difficulties, irrespective of noise exposure. A secondary analysis revealed that individuals with the highest levels of noise exposure had reduced outer hair cell function compared to individuals with the lowest levels of noise exposure, as measured by OAEs. OAE level was also related to PTA and EHF thresholds. High levels of noise exposure were also associated with a significant increase in ABR wave V latency, but only for males, and a higher prevalence and severity of hyperacusis. These findings suggest that there may be sub-clinical effects of noise exposure on various hearing metrics even at a relatively young age, but do not support a link between lifetime noise exposure and proxy measures of cochlear synaptopathy such as ABR wave amplitudes and SPiN. Closely monitoring OAEs, PTA and EHF thresholds when conventional PTA is within the clinically ‘normal’ range could provide a useful early metric of noise-induced hearing damage. This may be particularly relevant to early-career musicians as they progress through a period of intensive musical training, and thus interventions to protect hearing longevity may be vital

Supra-threshold auditory brainstem response amplitudes in humans:Test-retest reliability, electrode montage and noise exposure

The auditory brainstem response (ABR) is a sub-cortical evoked potential in which a series of well-defined waves occur in the first 10 ms after the onset of an auditory stimulus. Wave V of the ABR, particularly wave V latency, has been shown to be remarkably stable over time in individual listeners. However, little attention has been paid to the reliability of wave I which reflects auditory nerve activity. This ABR component has attracted interest recently, as wave I amplitude has been identified as a possible non-invasive measure of noise-induced cochlear synaptopathy. The current study aimed to determine whether ABR wave I amplitude has sufficient test-retest reliability to detect impaired auditory nerve function in an otherwise normal-hearing listener. Thirty normal-hearing females were tested, divided into equal groups of low- and high-noise exposure. The stimulus was an 80 dB nHL click. ABR recordings were made from the ipsilateral mastoid and from the ear canal (using a tiptrode). Although there was some variability between listeners, wave I amplitude had high test-retest reliability, with an intraclass correlation coefficient (ICC) comparable to that for wave V amplitude. There were slight gains in reliability for wave I amplitude when recording from the ear canal (ICC of 0.88) compared to the mastoid (ICC of 0.85). The summating potential (SP) and ratio of SP to wave I were also quantified and found to be much less reliable than measures of wave I and V amplitude. Finally, we found no significant differences in the amplitude of any wave components between low- and high-noise exposure groups. We conclude that, if the other sources of between-subject variability can be controlled, wave I amplitude is sufficiently reliable to accurately characterize individual differences in auditory nerve function

Recovering individual haplotypes and a contiguous genome assembly from pooled long-read sequencing of the diamondback moth (Lepidoptera: Plutellidae).

The assembly of divergent haplotypes using noisy long-read data presents a challenge to the reconstruction of haploid genome assemblies, due to overlapping distributions of technical sequencing error, intra-locus genetic variation and inter-locus similarity within these data. Here we present a comparative analysis of assembly algorithms representing overlap-layout-consensus, repeat graph and de Brujn graph methods. We examine how post-processing strategies attempting to reduce redundant heterozygosity interact with the choice of initial assembly algorithm and ultimately produce a series of chromosome-level assemblies for an agricultural pest, the diamondback moth, Plutella xylostella (L.). We compare evaluation methods and show that BUSCO analyses may overestimate haplotig removal processing in long-read draft genomes, in comparison to a k-mer method. We discuss the trade-offs inherent in assembly algorithm and curation choices and suggest that "best practice" is research question dependent. We demonstrate a link between allelic divergence and allele-derived contig redundancy in final genome assemblies and document the patterns of coding and non-coding diversity between redundant sequences. We also document a link between an excess of non-synonymous polymorphism and haplotigs that are unresolved by assembly or post-assembly algorithms. Finally, we discuss how this phenomenon may have relevance for the usage of noisy long-read genome assemblies in comparative genomics

Can village savings and loan groups be a potential tool in the malnutrition fight? Mixed method findings from Mozambique

Child malnutrition is a pervasive problem in sub-Saharan Africa that affects individual and national development. This article examines the impact of participation in village savings and loan (VSL) groups, alone and in combination with a rotating labor scheme called Ajuda Mútua (AM), on household and child nutritional outcomes in Nampula Province in Mozambique. It combines findings from an impact evaluation and a qualitative exploration of the dynamics underlying nutritional outcomes.Three pairs of districts were randomly allocated to two interventions (VSL or VSL. +. AM) or control. The impact evaluation utilized a prospective, longitudinal design. In total, 1276 households were surveyed at baseline in 2009 and three years later. Difference-in-difference propensity score matching models estimated program impacts on months of food sufficiency and household dietary diversity scores (HDDS) at the household level, and on individual dietary diversity scores (IDDS) and weight-for-age at the child level. In the qualitative study, in-depth interviews (IDIs) were completed with a subset of 36 VSL and 36 VSL. +. AM participants from two districts who had taken part in the two surveys. Transcripts were analyzed using thematic analysis.Survey data indicate that both interventions had a statistically significant, positive effect on months of food sufficiency. The HDDS increased for VSL. +. AM households and their matched controls; however, the increase was smaller for the VSL. +. AM group. The difference in increase between the two groups was statistically significant. At the child level, participation in VSL only was found to increase the IDDS. There was no significant effect for weight-for-age. Mean values for both the HDDS and the IDDS remained low. IDIs confirmed that there were improvements in seasonal and transitory food insecurity, which occur when recurring periods of extreme scarcity or sporadic crises are experienced. Due to the timing of the cycle, VSLs provided participants with an infusion of cash to purchase food during the hunger season. VSLs and AMs also offered mechanisms to cope with unexpected events through loans and social support. However, IDIs highlighted lack of money as a persistent challenge in accessing foods to supplement home-grown staples for a diversified nutritional intake. Though parents tended to be aware of the nutritional needs of children, they faced financial constraints in meeting them. There were also indications of a sex gap between control over resources by men and the role played by women in child nutrition.Findings underscore the potential of economic-strengthening activities such as VSLs for improving seasonal and transitory food security, but highlight the need for additional supporting interventions in order to overcome chronic nutritional challenges

Metabarcoding clarifies the diet of the elusive and vulnerable Australian tjakura (Great Desert Skink, Liopholis kintorei)

Introduction: Accurately quantifying the diet of species has implications for our understanding of their ecology and conservation. Yet, determining the dietary composition of threatened and elusive species in the wild is often difficult. Methods: This study presents the first dietary assessment of tjakura (Liopholis kintorei) using non-invasive sampling of scats and high-throughput sequencing techniques. Results: The tjakura in Uluru consumed 48 invertebrates, 27 plants, and two vertebrate taxa. Fruit flies (Leucophenga spp.), beetles (Harpalus spp. and Omorgus spp.), mosquitos (Culicidae spp.), termites (Termitidae spp.), spiked mallow (Malvastrum americanum), bush tomatoes (Solanum centrale), and wild turnip (Brassica tournefortii) comprised the majority of the diet. Analysis of similarity revealed that food items did not differ significantly between tjakura age groups, seasons, or time since the last fire, however, adults, hot season, and fire scar of 2018 showed a relatively higher prey diversity. Discussion: These high similarities in diet composition between age classes and fire scars indicate potential intraspecific competition when food resources are scarce. The diet diversity and potential plasticity observed in this study reflect a dietary ecology influenced by food availability rather than preference. Our study demonstrates that scat DNA metabarcoding is an important complementary tool to conventional scat analysis or indigenous knowledge as most food items we identified were previously not recorded through those methods

Outcomes of physical activity for people living with dementia: qualitative study to inform a Core Outcome Set

Background: The need for a Core Outcome Set to evaluate physical activity interventions for people living with dementia, across stages of disease and intervention settings has been established. This qualitative study precedes the consensus phase of developing this Core Outcome Set and aims to: (i) compare the outcomes identified by patients, carers and professionals to those previously reported in the literature; (ii) and understand “why” certain outcomes are considered important. Design and Methods: In-depth semi-structured interviews were conducted with people living with dementia, family carers and professionals (n=29). Firstly, the outcomes identified in the interviews were mapped to a list of outcomes reported in a recent literature review. Lastly, an in-depth thematic analysis were conducted to understand the importance of physical activity in dementia care. Results: A comprehensive, inductively derived list of 77 outcomes, common across stages of dementia and intervention setting, is now ready to be used in the consensus phase of this Core Outcome Set: ten of these were new outcomes generated by this qualitative study. Collectively, fFive themes explained why stakeholders perceived physical activity outcomes as important for people living with dementia: “being well and staying well”, “having a role towards others”, “maintaining identity”, “being connected to the present” and “delivering good quality care”. Conclusion: A total of 10 new outcomes of physical activity, not previously reported in recent literature, were identified by this qualitative study. Physical activity is considered important to people living with dementia due to its positive impact in multiple health outcomes for both patients and carers.publishe

British industrial relations pluralism in the era of neoliberalism

This article provides a broad overview of the pluralist tradition in UK industrial relations scholarship, identifying its defining characteristics and mapping its evolution in recent decades. It deals in turn with the following: the appreciation of the relative interests of workers and employers that lies at the heart of the pluralist frame of reference, the research agenda that flows from this understanding, pluralist conceptions of context and agency within industrial relations, the standards that pluralists habitually use when assessing the employment relationship, the targets and modes of critique that pluralists direct against intellectual opponents, and the prescriptions that pluralists offer for industrial relations reform. Throughout the article there is a focus on change within the pluralist tradition and the manner in which it has adapted to the hegemony of neoliberalism in the realms of both ideas and policy

CLIMB (the Cloud Infrastructure for Microbial Bioinformatics):an online resource for the medical microbiology community

The increasing availability and decreasing cost of high-throughput sequencing has transformed academic medical microbiology, delivering an explosion in available genomes while also driving advances in bioinformatics. However, many microbiologists are unable to exploit the resulting large genomics datasets because they do not have access to relevant computational resources and to an appropriate bioinformatics infrastructure. Here, we present the Cloud Infrastructure for Microbial Bioinformatics (CLIMB) facility, a shared computing infrastructure that has been designed from the ground up to provide an environment where microbiologists can share and reuse methods and data