Application of a Hermite-based measure of non-Gaussianity to normality tests and independent component analysis.

In the analysis of neural data, measures of non-Gaussianity are generally applied in two ways: as tests of normality for validating model assumptions and as Independent Component Analysis (ICA) contrast functions for separating non-Gaussian signals. Consequently, there is a wide range of methods for both applications, but they all have trade-offs. We propose a new strategy that, in contrast to previous methods, directly approximates the shape of a distribution via Hermite functions. Applicability as a normality test was evaluated via its sensitivity to non-Gaussianity for three families of distributions that deviate from a Gaussian distribution in different ways (modes, tails, and asymmetry). Applicability as an ICA contrast function was evaluated through its ability to extract non-Gaussian signals in simple multi-dimensional distributions, and to remove artifacts from simulated electroencephalographic datasets. The measure has advantages as a normality test and, for ICA, for heavy-tailed and asymmetric distributions with small sample sizes. For other distributions and large datasets, it performs comparably to existing methods. Compared to standard normality tests, the new method performs better for certain types of distributions. Compared to contrast functions of a standard ICA package, the new method has advantages but its utility for ICA is more limited. This highlights that even though both applications-normality tests and ICA-require a measure of deviation from normality, strategies that are advantageous in one application may not be advantageous in the other. Here, the new method has broad merits as a normality test but only limited advantages for ICA.

Evaluation of a professional development experience designed to equip school support staff with skills to facilitate youth mental health promotion.

Background: Public policy across the world is increasingly focusing on the role of mental health promotion in whole of health strategies. There is a growing evidence-base that mental health promotion, delivered by trained facilitators, is effective in promoting self-awareness and self-care to prevent the damaging effects of ongoing stress in one's life and to promote early detection of any possible emerging mental health problems. Within Australia, however, few clinicians or school staff are confident or trained in mental health promotion.Aims: This paper reports the results of a two-day training designed for facilitators of a mental health program for secondary-school students. The goal was to develop facilitators' knowledge and understanding of best practice in youth mental health promotion and to increase their confidence in delivering the program.Design: A mixed methods evaluation assessed the impact that a solution-focused training program had on participating facilitators.Methods: A questionnaire was created and included eight quantitative items and one open ended, qualitative question. Twenty-seven nurses and guidance officers from central Queensland were recruited via convenience sampling and data were analysed using descriptive statistics and thematic analysis.Results: The evaluation revealed that participants' perception of their ability to facilitate a youth mental health program significantly improved after completing the training. Qualitative data indicated that participants found the professional development experience to be valuable, provide useful and transferable skills, and believed it to be necessary for mental health promotion work.Conclusion: By providing detailed description of the program's content and processes, other mental health professionals may be inspired to further develop effective learning experiences.

The factors influencing the effective early career and rapid transition to a nursing specialty in differing contexts of practice: a modified Delphi consensus study.

OBJECTIVES: This study aimed to test and further develop the 'Early Career and Rapid Transition to a Nursing Specialty' (TRANSPEC) model to a nursing specialty developed from a systematic review. Semi-structured interviews of specialist clinically based nurses and a consensus Delphi study with an expert panel were used to expand and achieve consensus, agreement, reliability and stability of the model. DESIGN: A modified Delphi, two rounds (64 and 52 Likert items) of reiterative online questionnaires and one round as a nominal group technique, was informed by qualitative thematic analysis of semi-structured interviews. SETTING AND PARTICIPANTS: Interviews with 14 specialists clinical practicing registered nurses and a panel of 25 national experts participated in the Delphi study. RESULTS: The interview participants experienced 14 rapid transitions and three were early career transition. The overarching themes from the preliminary model were confirmed and further expanded. These were the self (personal and professional); the transition processes (final and informal); a sense of belonging; and the overarching context of practice over a time continuum. In the Delphi, the highest rating item was 'Specialty work colleagues respect, include, support, and accept specialist nurse on completion of transition processes'. Pre-entry was highlighted as an important time point prior to transition. All items reaching consensus were included in the final model. Cronbach α increased from 0.725 to 0.875 for the final model. CONCLUSIONS: The TRANSPEC model is a valid and reliable evidence-based tool for use in the career pathway and development of nursing specialists. Using the Benner model 'Novice to Expert' after the novice incomer phase is achieved, further lifelong learning development will transform the novice specialist over time continuum.

From incomer to insider: The development of the TRANSPEC model - A systematic review of the factors influencing the effective rapid and early career TRANsition to a nursing SPECiality in differing contexts of practice.

OBJECTIVE: Shortages in the speciality nursing workforce, both nationally and internationally are driving the need for the development of an evidence-based model to inform recruitment and retention into speciality nursing practice. This study aimed to identify the factors influencing rapid and early career transition into speciality nursing practice. METHODS: A comprehensive systematic review of the literature was undertaken using a convergent qualitative synthesis design where results from qualitative, quantitative and mixed methods studies were transformed into qualitative findings. Databases included CINAHL, Medline, Scopus and PsycINFO. Search terms were: nurse, early career, rapid career, transition, specialty, and Medical Subject Heading terms included: professional development and educational, nursing, and continuing. Using validated tools, papers were independently assessed by a minimum of two reviewers. RESULTS: Twenty-three research articles were included. There were no randomized control trials. Through thematic analysis and matrix mapping of the results, the TRANSPEC model was developed. The model outlines three phases of transition: pre-entry, incomer and insider. There has been little focus on pre-entry with programs being designed at the incomer and insider phases. Impacting on these phases are three concepts: the self (professional and personal), the transition processes (informal and formal) and a sense of belonging. The overarching theme influencing the phases and concepts is the context of practice. Enablers and inhibitors influence successful transition and therefore impact on recruitment and retention. Each nurse's transition is influenced by time. CONCLUSIONS: For successful transition, the enablers and inhibitors impacting on the three concepts, phases and the context of practice need to be considered when developing any program. It is apparent that while previous studies have focused on the transition processes, such as curricula, the development of the self and a sense of belonging are also essential to successful transition. Further studies should include the pre-entry phase.

Building resilience in regional youth: Impacts of a universal mental health promotion programme.

Mental health is a leading health issue facing young people today, particularly those living in rural and regional areas. Although public policy supports schools-based health promotion, there is limited evidence of the efficacy of such programmes and the elements that enhance successful implementation in rural and regional areas. A study was designed to evaluate a mental health promotion programme, delivered collaboratively by nurses, guidance officers, and teachers, to 850 young people from 23 rural and regional high schools in Queensland, Australia. The study aims were to determine what effect the intervention had on young peoples' resilience, coping, and self-efficacy, and to understand the implications of delivering the programme in the regional Queensland school setting. Students completed self-report measures of self-efficacy, resilience, and coping strategies pre- and postprogramme, as well as at 8-week follow-up. We found that after programme completion there was a significant increase in self-efficacy and in the number of positive coping strategies used by the participating young people. Qualitative data indicated that participants benefited from the collaboration between health and education sectors; that is, nurses, guidance officers, and teachers delivered the programme together in ways that were perceived to be respectful of young people and effectively discussion-based, and engaging.

Merging contemporary learning theory with mental health promotion to produce an effective schools-based program.

Approximately three quarters of all major mental disorders begin in adolescence. Finding ways to buffer against stress, access social support and connection and flexibly draw upon a range of coping mechanisms are vital strategies that young people can use to promote mental health and wellbeing and to navigate this turbulent life transition successfully. Within Australia, like other parts of the world such as the UK and the USA, it is a sad reality that when young people do become distressed they are not self-caring or supporting others effectively, and not seeking or receiving appropriate help. In order to respond proactively to this issue, a nurse-initiated mental health promotion program was developed. It is termed, iCARE, which stands for Creating Awareness, Resilience and Enhanced Mental Health. The aim of this paper is to discuss the underpinning educational theory that assists in developing in young people a sense of belonging, empathy, self-care and resilience, and why the strategies chosen to engage young people are likely to be effective.

Estimating the amount of information conveyed by a population of neurons.

Recent technological advances have made the simultaneous recording of the activity of many neurons common. However, estimating the amount of information conveyed by the discharge of a neural population remains a significant challenge. Here we describe our recently published analysis method that assists in such estimates. We describe the key concepts and assumptions on which the method is based, illustrate its use with data from both simulated and real neurons recorded from the lateral geniculate nucleus of a monkey, and show how it can be used to calculate redundancy and synergy among neuronal groups.

Spiking neurons and the first passage problem.

We derive a model of a neuron's interspike interval probability density through analysis of the first passage problem. The fit of our expression to retinal ganglion cell laboratory data extracts three physiologically relevant parameters, with which our model yields input-output features that conform to laboratory results. Preliminary analysis suggests that under common circumstances, local circuitry readjusts these parameters with changes in firing rate and so endeavors to faithfully replicate an input signal. Further results suggest that the so-called principle of sloppy workmanship also plays a role in evolution's choice of these parameters.

Estimating the amount of information carried by a neuronal population.

Although all brain functions require coordinated activity of many neurons, it has been difficult to estimate the amount of information carried by a population of spiking neurons. We present here a Fourier-based method for estimating the information delivery rate from a population of neurons, which allows us to measure the redundancy of information within and between functional neuronal classes. We illustrate the use of the method on some artificial spike trains and on simultaneous recordings from a small population of neurons from the lateral geniculate nucleus of an anesthetized macaque monkey.

Safety testing of infracyanine green using retinal pigment epithelium and glial cell cultures.

PURPOSE: To undertake safety testing of infracyanine green (IFCG) in a cell culture model. METHODS: Experiments were undertaken in a cell culture model used previously to perform safety testing of indocyanine green (ICG). Human retinal pigment epithelium (RPE) and Müller cells were exposed to IFCG for 5 minutes, over a range of concentrations up to 0.5%. Experiments were repeated, using double-staining with trypan blue. Cell viability was measured at days 1, 5, and 15 using a mitochondrial dehydrogenase assay and a fluorescent live-dead probe containing calcein and ethidium homodimer-1. Viability was measured after exposure to 0.5% IFCG and 5 minutes of illumination with a vitrectomy endolight powered by a xenon light source. RESULTS: RPE viability was not reduced over the range of concentrations and follow-up intervals. RPE cells exposed to IFCG and illumination had reduced viability relative to the negative control (cells exposed to saline), but not relative to those exposed to saline and illumination. Glial cells showed reduced viability at days 1 and 5, but not day 15. Illumination did not further reduce viability. CONCLUSIONS: IFCG has been advocated as a safer macular vital stain than ICG. These results suggest that it is less likely to produce phototoxicity, but despite being nearly iso-osmolar, IFCG also produces damage in cultured glial cells.

Safety testing of indocyanine green and trypan blue using retinal pigment epithelium and glial cell cultures.

PURPOSE: Indocyanine green (ICG) and trypan blue have been advocated as vital stains for use during macular surgery. The safety of these agents was tested using a cell culture model. METHODS: Human retinal pigment epithelium (RPE) and Müller cell lines were exposed to ICG over a range of concentrations up to 0.5%, and trypan blue up to 0.2%. Cells were exposed to each dye for 5, 15, or 30 minutes, rinsed, and incubated 24 hours. Cell viability was measured using a mitochondrial dehydrogenase-assay and fluorescent live-dead probe. Experiments were repeated using 0.5% and 1% ICG and 0.06% and 0.12% trypan blue, with follow-up at 0, 1, 5, and 15 days. ICG experiments were repeated in the presence of illumination from a xenon light-source channeled through a surgical endolight, and using reduced osmolarity solutions of 0.1%, 0.5%, and 1% (185 vs. 275 mOsM). RESULTS: There was no clear relationship between cell viability and the concentration of the agent or duration of follow-up, except in RPE cells exposed to 1% ICG. These showed a linear (R(2) 0.9952) decline in viability with time, with a significant reduction by day 15 (P = 0.016). RPE cells exposed to ICG and illumination were not significantly different from the negative control, but when illumination was combined with low osmolarity, viability was reduced (P = 0.0016). ICG and illumination reduced Müller cell viability (P < 0.0001 for both 185 and 275 mOsM). Müller cells incubated with 185 mOsM 1% ICG showed a significant reduction in viability (P < 0.0001) not seen with the 185 mOsM 0.5% or 0.1% solutions or in the low-osmolarity RPE groups. CONCLUSIONS: The combination of exposure to 0.5% ICG and the newer endoillumination light-sources can damage cultured Müller cells. Although the preparations of ICG most commonly used clinically did not produce significant damage, relatively small changes in ICG osmolarity and concentration did. This suggests that safety margins are not large. Trypan blue is safe in a cell culture model.

Tail-anchored and signal-anchored proteins utilize overlapping pathways during membrane insertion.

Tail-anchored proteins are a distinct class of membrane proteins that are characterized by a C-terminal membrane insertion sequence and a capacity for post-translational integration. Although it is now clear that tail-anchored proteins are inserted into the membrane at the endoplasmic reticulum (ER), the molecular basis for their integration is poorly understood. We have used a cross-linking approach to identify ER components that may be involved in the membrane insertion of tail-anchored proteins. We find that several newly synthesized tail-anchored proteins are transiently associated with a defined subset of cellular components. Among these, we identify several ER proteins, including subunits of the Sec61 translocon, Sec62p, Sec63p, and the 25-kDa subunit of the signal peptidase complex. When we analyze the cotranslational membrane insertion of a comparable signal-anchored protein we find the nascent polypeptide associated with a similar set of ER components. We conclude that the pathways for the integration of tail-anchored and signal-anchored membrane proteins at the ER exhibit a substantial degree of overlap, and we propose that this reflects similarities between co- and post-translational membrane insertion.