Liquid-immersible electrostatic ultrasonic transducer

A broadband megahertz range electrostatic acoustic transducer for use in a liquid environment is described. A liquid tight enclosure includes a metallic conducting membrane as part of its outside surface and has a means inside the liquid tight enclosure for applying a tension to the membrane and for mounting an electrode such that the flat end of the electrode is aproximately parallel to the membrane. The invention includes structure and a method for ensuring that the membrane and the flat end of the electrode are exactly parallel and a fixed predetermined distance from each other

The state of the art in non-pharmacological interventions for developmental stuttering. Part 2: qualitative evidence synthesis of views and experiences.

BACKGROUND: A range of interventions have been developed to treat stuttering in recent years. The effectiveness of these interventions has largely been assessed in studies focusing on the impact of specific types of therapy on patient outcomes. Relatively little is known about the factors that influence how the delivery and impact of different types of intervention may be experienced from the perspective of both people who deliver as well as those who receive interventions. AIMS: To synthesize the available evidence in relation to factors that might enhance or mitigate against successful outcomes following interventions for stuttering by identifying and synthesizing relevant qualitative research that explored the experiences of people delivering and receiving interventions that aim to improve fluency. METHODS & PROCEDURES: We carried out a systematic review including research that had used in-depth interviews and focus groups and conducted a substantive qualitative analysis of the data collected. Included study populations were either adults or children affected by a diagnosed stutter and/or providers of therapy for stuttering. An iterative approach was used to search for published qualitative evidence in relevant databases from 1990 to 2014. Retrieved citations were sifted for relevance and the data from articles that met the inclusion criteria were extracted. Each included paper was assessed for quality and a thematic analysis and synthesis of findings was carried out. MAIN CONTRIBUTION: Synthesized qualitative evidence highlights the changing experiences for people who stutter both historically and, for individuals, over the life course. Barriers and facilitators to the implementation of interventions for stuttering are encountered at the individual, intervention, interpersonal and social levels. Interventions may be particularly pertinent at certain transition points in the life course. Attention to emotional as well as practical aspects of stuttering is valued by people receiving therapy. The client-therapist relationship and support from others are also key factors in achieving successful outcomes. CONCLUSIONS & IMPLICATIONS: A synthesis of qualitative findings from published papers has added to the effectiveness data reported in an accompanying paper in understanding how stuttering impacts on people across the life course. Evidence suggests that a client-centred and individually tailored approach enhances the likelihood of successful intervention outcomes through attention to emotional, situational and practical needs

Systematic review of the evidence on housing interventions for ‘housing-vulnerable’ adults and its relationship to wellbeing

Access to safe, good quality affordable housing is essential to wellbeing and housing related factors can have an important influence on neighbourliness and sense of community belonging. A recent scoping review on housing and wellbeing identified a lack of review-level evidence around the impact of housing interventions on wellbeing of people who are vulnerable to discrimination or exclusion in relation to housing (Preston et al., 2016). This systematic review was commissioned to address that gap. We synthesise and consider the quality of evidence on how housing interventions can contribute to improving the lives of adults who are vulnerable in relation to the security of their housing tenure (‘housing-vulnerable’ adults)

Thermoelectric power of nondegenerate Kane semiconductors under the conditions of mutual electron-phonon drag in a high electric field

The thermoelectric power of nondegenerate Kane semiconductors with due regard for the electron and phonon heating, and their thermal and mutual drags is investigated. The electron spectrum is taken in the Kane two-band form. It is shown that the nonparabolicity of electron spectrum significantly influences the magnitude of the thermoelectric power and leads to a change of its sign and dependence on the heating electric field. The field dependence of the thermoelectric power is determined analytically under various drag conditions.Comment: 25 pages, RevTex formatted, 3 table

Synthetic Mudscapes: Human Interventions in Deltaic Land Building

In order to defend infrastructure, economy, and settlement in Southeast Louisiana, we must construct new land to mitigate increasing risk. Links between urban environments and economic drivers have constrained the dynamic delta landscape for generations, now threatening to undermine the ecological fitness of the entire region. Static methods of measuring, controlling, and valuing land fail in an environment that is constantly in flux; change and indeterminacy are denied by traditional inhabitation. Multiple land building practices reintroduce deltaic fluctuation and strategic deposition of fertile material to form the foundations of a multi-layered defence strategy. Manufactured marshlands reduce exposure to storm surge further inland. Virtual monitoring and communication networks inform design decisions and land use becomes determined by its ecological health. Mudscapes at the threshold of land and water place new value on former wastelands. The social, economic, and ecological evolution of the region are defended by an expanded web of growing land

Stochastic population growth in spatially heterogeneous environments

Classical ecological theory predicts that environmental stochasticity increases extinction risk by reducing the average per-capita growth rate of populations. To understand the interactive effects of environmental stochasticity, spatial heterogeneity, and dispersal on population growth, we study the following model for population abundances in $n$ patches: the conditional law of $X_{t+dt}$ given $X_t=x$ is such that when $dt$ is small the conditional mean of $X_{t+dt}^i-X_t^i$ is approximately $[x^i\mu_i+\sum_j(x^j D_{ji}-x^i D_{ij})]dt$, where $X_t^i$ and $\mu_i$ are the abundance and per capita growth rate in the $i$-th patch respectivly, and $D_{ij}$ is the dispersal rate from the $i$-th to the $j$-th patch, and the conditional covariance of $X_{t+dt}^i-X_t^i$ and $X_{t+dt}^j-X_t^j$ is approximately $x^i x^j \sigma_{ij}dt$. We show for such a spatially extended population that if $S_t=(X_t^1+...+X_t^n)$ is the total population abundance, then $Y_t=X_t/S_t$, the vector of patch proportions, converges in law to a random vector $Y_\infty$ as $t\to\infty$, and the stochastic growth rate $\lim_{t\to\infty}t^{-1}\log S_t$ equals the space-time average per-capita growth rate \sum_i\mu_i\E[Y_\infty^i] experienced by the population minus half of the space-time average temporal variation \E[\sum_{i,j}\sigma_{ij}Y_\infty^i Y_\infty^j] experienced by the population. We derive analytic results for the law of $Y_\infty$, find which choice of the dispersal mechanism $D$ produces an optimal stochastic growth rate for a freely dispersing population, and investigate the effect on the stochastic growth rate of constraints on dispersal rates. Our results provide fundamental insights into "ideal free" movement in the face of uncertainty, the persistence of coupled sink populations, the evolution of dispersal rates, and the single large or several small (SLOSS) debate in conservation biology.Comment: 47 pages, 4 figure

Digital and online symptom checkers and health assessment/triage services for urgent health problems: systematic review

Objectives In England, the NHS111 service provides assessment and triage by telephone for urgent health problems. A digital version of this service has recently been introduced. We aimed to systematically review the evidence on digital and online symptom checkers and similar services. Design Systematic review. Data sources We searched Medline, Embase, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Health Management Information Consortium, Web of Science and ACM Digital Library up to April 2018, supplemented by phrase searches for known symptom checkers and citation searching of key studies. Eligibility criteria Studies of any design that evaluated a digital or online symptom checker or health assessment service for people seeking advice about an urgent health problem. Data extraction and synthesis Data extraction and quality assessment (using the Cochrane Collaboration version of QUADAS for diagnostic accuracy studies and the National Heart, Lung and Blood Institute tool for observational studies) were done by one reviewer with a sample checked for accuracy and consistency. We performed a narrative synthesis of the included studies structured around pre-defined research questions and key outcomes. Results We included 29 publications (27 studies). Evidence on patient safety was weak. Diagnostic accuracy varied between different systems but was generally low. Algorithm-based triage tended to be more risk averse than that of health professionals. There was very limited evidence on patients’ compliance with online triage advice. Study participants generally expressed high levels of satisfaction, although in mainly uncontrolled studies. Younger and more highly educated people were more likely to use these services. Conclusions The English ‘digital 111’ service has been implemented against a background of uncertainty around the likely impact on important outcomes. The health system may need to respond to short-term changes and/or shifts in demand. The popularity of online and digital services with younger and more educated people has implications for health equity. PROSPERO registration number CRD42018093564

Instrumentation for Routine Analysis of Acrylamide in French Fries: Assessing Limitations for Adoption

The purpose of this experimental review was to detect acrylamide in French fries using methods most adaptable to the food process industry for quality control assessment of products. French fries were prepared at different cook times using the same fryer oil over a five-day period to assess the influence of oil degradation and monitor trends in acrylamide formation. Acrylamide detection was performed using LC-MS, GC-MS and FT-NIR. The low levels of acrylamide produced during frying, low molecular weight of the analyte, and complexity of the potato matrix make routine acrylamide measurement challenging in a well-outfitted analytical lab with trained personnel. The findings of this study are presented from the perspective of pros and cons of each acrylamide measurement method in enough detail for food processors to appraise the method that may work best for them based on their available instrumentation and extent of personnel training