151 research outputs found

    Multi-Modal and Short-Range Transmission Loss in Ice-Covered, Near-Shore Arctic Waters

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    In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 km off the coast of Barrow, Alaska on shore-fast, first year ice, approximately 1 m thick. To determine the propagation characteristics of various sound sources, Frequency Response Functions (FRFs) were measured between a source location and several receiver locations at various distances from 1 m to 1 km. The primary sources used for this experiment were, an underwater speaker with various tonal outputs, an instrumented impact-hammer on the ice, and a propane cannon that produced an acoustic blast wave in air. The transmission characteristics of the multipath propagation (air, ice, water) are investigated and reported

    ACOUSTIC LOCALIZATION TECHNIQUES FOR APPLICATION IN NEAR-SHORE ARCTIC ENVIRONMENTS

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    The Arctic environment has undergone significant change in recent years. Multi-year ice is no longer prevalent in the Arctic. Instead, Arctic ice melts during summer months and re-freezes each winter. First-year ice, in comparison to multi-year ice, is different in terms of its acoustic properties. Therefore, acoustic propagation models of the Arctic may no longer be valid. The open water in the Arctic for longer time periods during the year invites anthropogenic traffic such as civilian tourism, industrial shipping, natural resource exploration, and military exercises. It is important to understand sound propagation in the first-year ice environment, especially in near-shore and shallow-water regions, where anthropogenic sources may be prevalent. It is also important to understand how to detect, identify, and track the anthropogenic sources in these environments in the absence of large acoustic sensory arrays. The goals of this dissertation are twofold: 1) Provide experimental transmission loss (TL) data for the Arctic environment as it now exists, that it may be used to validate new propagation models, and 2) Develop improved understanding of acoustic vector sensor (AVS) performance in real-world applications such as the first-year Arctic environment. Underwater and atmospheric acoustic TL have been measured in the Arctic environment. Ray tracing and parabolic equation simulations have been used for comparison to the TL data. Generally good agreement is observed between the experimental data and simulations, with some discrepancies. These discrepancies may be eliminated in the future with the development of improved models. Experiments have been conducted with underwater pa and atmospheric pp AVS to track mechanical noise sources in real-world environments with various frequency content and signal to noise ratio (SNR). A moving standard deviation (MSD) processing routine has been developed for use with AVS. The MSD processing routine is shown to be superior to direct integration or averaging of intensity spectra for direction of arrival (DOA) estimation. DOA error has been shown to be dependent on ground-reflected paths for pp AVS with analytical models. Underwater AVS have been shown to be feasible to track on-ice sources and atmospheric AVS have been shown feasible to track ground vehicle sources

    Abuse in the caregiving relationship between older people with memory disorders and family caregivers: A systematic review

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    Aim To synthesize what is known about elder abuse and relationship factors associated with abuse between caregivers and older people with memory disorders at home. Background Concerns about abuse in the caring relationship between older people with memory disorders and family caregivers have increased. Abuse is associated with negative outcomes on older people's health, quality of life, and zest for life. Abuse in the caring relationship manifests in financial exploitation, neglect, mistreatment, and physical issues. Design Systematic review. Data Sources Databases including Scopus, PubMed/Medline, SveMed+, Cinalh, SonINDEX, and ProQuest were searched using keywords about abuse in the caring relationship between older people with memory disorders and family caregivers at home. Articles published between 2005–2019 were retrieved and underwent data analysis and knowledge synthesis. Review Methods The review was presented under the categories of the dyadic approach of elder abuse in connection with the role of caregiver (risk) and care recipient (vulnerability) by Fulmer et al. (2005). Results The search process led to 12 quantitative studies, including an intervention, a prospective, nine surveys, and a cross‐sectional structural interview. Findings were synthesized and presented under ‘personal’, ‘physical and psychological’, and ‘social’ domains indicating the bilateral roles of caregiver and care recipient leading to abuse. Conclusion This review depicted factors influencing abuse in the caring relationship between older people with memory disorders and their family caregivers at home. They included family caregivers’ psychological issues, knowledge of memory disorders and modifications, previous caring relationship, social support, number of care recipients, and care recipients’ functional level. Impact This review identifies what influences elder abuse by family caregivers using the dyadic approach and explains how abuse can be prevented through suggested strategies. The review findings are relevant to multidisciplinary healthcare providers and can guide the provision of support, screening and assessment, educational programs, and legislative initiatives

    What is an "adult protection" issue? Victims, perpetrators and the professional construction of adult protection issues

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    Drawing on data from a Scottish research study, this paper explores the relationship of professionals’ perceptions about specific perpetrators and victims to their constructions of ‘adult protection’ issues in practice. It finds that professionals’ perceptions of victim distress did not consistently coincide with the construction of adult protection issues, whilst the connection to any assessment of victims’ heightened vulnerability in specific cases was not clear. With respect to perpetrators, implicit practice rules were evidenced which differed from explicit policy criteria. In particular, there were different rules for relatives, staff and service user perpetrators, whilst harms attributed to institutions were de-emphasized. Explanations of the findings are advanced based on the complex power relations underpinning practice but unacknowledged in policies. More research is recommended to deepen this analysis in a changing policy context, to foreground service user perspectives, and to contextualize harms potentially resolvable through adult support and protection/safeguarding routes with respect to harms better addressed in other ways

    Growth or decline in the Church of England during the decade of Evangelism: did the Churchmanship of the Bishop matter?

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    The Decade of Evangelism occupied the attention of the Church of England throughout the 1990s. The present study employs the statistics routinely published by the Church of England in order to assess two matters: the extent to which these statistics suggest that the 43 individual dioceses finished the decade in a stronger or weaker position than they had entered it and the extent to which, according to these statistics, the performance of dioceses led by bishops shaped in the Evangelical tradition differed from the performance of dioceses led by bishops shaped in the Catholic tradition. The data demonstrated that the majority of dioceses were performing less effectively at the end of the decade than at the beginning, in terms of a range of membership statistics, and that the rate of decline varied considerably from one diocese to another. The only exception to the trend was provided by the diocese of London, which experienced some growth. The data also demonstrated that little depended on the churchmanship of the diocesan bishop in shaping diocesan outcomes on the performance indicators employed in the study

    Discussing atypical sexual harassment as a controversial issue in bystander programmes: One UK campus study

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    This research emanates from an anti-sexual violence bystander programme delivered at an English university. Fifteen students were identified through purposive and convenience sampling to take part in focus groups. Discussions emerged regarding atypical sexual harassment. There is a gap in the literature exploring sexual harassment outside of the male perpetrator and female victim narrative which this paper contributes to. This paper considers four conversational themes: ‘unwanted touching: women to men’, ‘sexual banter: women to men’, ‘sexual stereotypes: women and men’, and ‘developing stronger ethical subjectivity’. This paper recognises most sexual harassment occurs from men to women, and acknowledges criticism of focussing otherwise when resources are limited, noting this risks obscuring the enduring power differentials between the sexes. It contends that exploring a controversial issue, such as male experience of sexual harassment, might help bystander programmes by developing ethical subjectivity in undergraduate students. Exploring sexual behaviour as a spectrum may lead to counter hegemonic discourses to emerge

    Functional diversity of mesograzers in an eelgrass-epiphyte system

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    Historically, small invertebrate grazers in marine plant communities have been considered to be a relatively homogeneous group in their impact on ecosystem processes. However, recent studies propose that species composition is an important agent in determining grazer effects. We used four mesocosm experiments to test the biomass-specific and density-dependent effects of common mesograzers in temperate regions (Littorina littorea, Rissoa membranacea, Idotea baltica and Gammarus oceanicus) on epiphyte and eelgrass biomass and productivity. Mesograzer species identity strongly influenced epiphyte accumulation and eelgrass growth, where Rissoa was the most efficient mesograzer (per biomass) and Gammarus had the weakest impact. Density-dependent effects varied considerably among species. Both gastropod species reduced epiphyte accumulation in direct proportion to their density, and Littorina had the strongest negative effect on epiphyte biomass. The impact of Idotea seemed to level off to a threshold value and Gammarus had no density-dependent effect on epiphyte accumulation at all. Rissoa and Idotea increased eelgrass productivity in accordance with their effect on epiphyte accumulation, whereas Littorina showed a less positive effect than could be expected by its strong impact on epiphyte biomass. Gammarus had no significant impact on eelgrass growth. Our results show that the different functional traits of superficially similar mesograzers can have important consequences for ecosystem processes in macrophyte systems

    Impact of the TCR Signal on Regulatory T Cell Homeostasis, Function, and Trafficking

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    Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4+ T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional null allele of the gene encoding p56Lck, we have examined the importance of TCR signaling in Treg cells. Inactivation of p56Lck resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56Lck in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR
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