29 research outputs found

    Connecting magnetic towers with Faraday rotation gradients in active galactic nuclei jets

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    The idea that systematic Faraday Rotation gradients across the parsec-scale jets of active galactic nuclei (AGNs) can reveal the presence of helical magnetic (B) fields has been around since the early 1990s, although the first observation of this phenomenon was about ten years later. These gradients are taken to be due to the systematic variation of the line-of-sight B field across the jet. We present here, the parsec-scale Faraday Rotation distributions for the BL Lac objects 0716+714 and 1749+701, based on polarization data obtained with the Very Long Baseline Array at two wavelengths near each of the 2 cm, 4 cm and 6 cm bands (0716+714) and at four wavelengths in the range 18-22 cm (1749+701). The Rotation Measure (RM) maps for both these sources indicate systematic gradients across their jets, as expected if these jets have helical B fields. The significance of these transverse RM gradients is >3 sigma in all cases. We present the results of Monte Carlo simulations directly demonstrating the possibility of observing such transverse RM gradients even if the intrinsic jet structure is much narrower than the observing beam. We observe an intriguing new feature in these sources, a reversal in the direction of the gradient in the jet as compared to the gradient in the core region. This provides new evidence to support models in which field lines emerging from the central region of the accretion disc and closing in the outer region of the accretion disc are both 'wound up' by the differential rotation of the disc. The net observed RM gradient will essentially be the sum effect of two regions of helical field, one nested inside the other. The direction of the net RM gradient will be determined by whether the inner or outer helix dominates the RM integrated through the jet, and RM gradient reversals will be observed if the inner and outer helical fields dominate in different regions of the jet. This potentially provides new insights about the overall configuration of the jet B fields

    Journey through the Brain

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    The brain is our most important organ and perhaps the least well understood. Our brain is the “command station” for our body. It controls what we think, what we feel and what we do. It is the home of our emotions and personality. It makes sense of our experiences. But how does the brain work? The truth is that, after decades of research, scientists and doctors are only now beginning to figure out that question. We know that different types of cells in the brain work together to form certain areas which have specialist roles in memory, vision and logical thinking. We also know that hormones and chemicals influence our brain and our emotions and that we are very sensitive to changes in their levels. We know that the different brain areas mature at different stages and are connected by tracts, rather like railway lines, which can sometimes go astray and lead to illnesses. And finally we know that by looking in the blood we can find clues, called biomarkers, which may ultimately help us to understand and predict brain disorders. Through this book we want to help everyone to understand the workings of the brain through pictures and cartoons. If you would like to learn more about these pictures go to our website rcsi.ie/brainjourneyhttp://epubs.rcsi.ie/psychbooks/1000/thumbnail.jp

    Influences on Decision-Making Regarding Antipsychotic Prescribing in Nursing Home Residents With Dementia: A Systematic Review and Synthesis of Qualitative Evidence.

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    BACKGROUND: Antipsychotic prescribing is prevalent in nursing homes for the management of behavioral and psychological symptoms of dementia (BPSD), despite the known risks and limited effectiveness. Many studies have attempted to understand this continuing phenomenon, using qualitative research methods, and have generated varied and sometimes conflicting findings. To date, the totality of this qualitative evidence has not been systematically collated and synthesized. AIMS: To synthesize the findings from individual qualitative studies on decision-making and prescribing behaviors for antipsychotics in nursing home residents with dementia, with a view to informing intervention development and quality improvement in this field. METHODS: A systematic review and synthesis of qualitative evidence was conducted (PROSPERO protocol registration CRD42015029141). Six electronic databases were searched systematically from inception through July 2016 and supplemented by citation, reference, and gray literature searching. Studies were included if they used qualitative methods for both data collection and analysis, and explored antipsychotic prescribing in nursing homes for the purpose of managing BPSD. The Critical Appraisal Skills Program assessment tool was used for quality appraisal. A meta-ethnography was conducted to synthesize included studies. The Confidence in the Evidence from Reviews of Qualitative research approach was used to assess the confidence in individual review findings. All stages were conducted by at least 2 independent reviewers. RESULTS: Of 1534 unique records identified, 18 met the inclusion criteria. Five key concepts emerged as influencing decision-making: organizational capacity; individual professional capability; communication and collaboration; attitudes; regulations and guidelines. A "line of argument" was synthesized and a conceptual model constructed, comparing this decision-making process to a dysfunctional negative feedback loop. Our synthesis indicates that when all stakeholders come together to communicate and collaborate as equal and empowered partners, this can result in a successful reduction in inappropriate antipsychotic prescribing. CONCLUSIONS: Antipsychotic prescribing in nursing home residents with dementia occurs in a complex environment involving the interplay of various stakeholders, the nursing home organization, and external influences. To improve the quality of antipsychotic prescribing in this cohort, a more holistic approach to BPSD management is required. Although we have found the issue of antipsychotic prescribing has been extensively explored using qualitative methods, there remains a need for research focusing on how best to change the prescribing behaviors identified

    Nurses', physicians' and radiographers' perceptions of the safety of a nurse prescribing of ionising radiation initiative: A cross-sectional survey

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    Background: A new initiative was introduced in Ireland following legislative changes that allowed nurses with special training to prescribe ionising radiation (X-ray) for the first time. A small number of studies on nurse prescribing of ionising radiation in other contexts have found it to be broadly as safe as ionising radiation prescribing by physicians. Sociological literature on perceptions of safety indicates that these tend to be shaped by the ideological position of the professional rather than based on objective evidence. Objectives: To describe, compare and analyse perceptions of the safety of a nurse prescribing of ionising radiation initiative across three occupational groups: nursing, radiography and medicine. Design: A cross-sectional survey design. Settings: Participants were drawn from a range of clinical settings in Ireland. Participants: Respondents were 167 health professionals comprised of 49 nurses, 91 radiographers, and 27 physicians out of a total of 300 who were invited to participate. Non-probability sampling was employed and the survey was targeted specifically at health professionals with a specific interest in, or involvement with, the development of the nurse prescribing of ionising radiation initiative in Ireland. Methods: Comparisons of perspectives on the safety of nurse prescribing of ionising radiation across the three occupational groups captured by questionnaire were analysed using the Kruskal–Wallis H test. Pairwise post hoc tests were conducted using the Mann–Whitney U test. Results: While the majority of respondents from all three groups perceived nurse prescribing of ionising radiation to be safe, the extent to which this view was held varied. A higher proportion of nurses was found to display confidence in the safety of nurse prescribing of ionising radiation compared to physicians and radiographers with differences between nurses’ perceptions and those of the other two groups being statistically significant. Conclusion: That an occupational patterning emerged suggests that perceptions about safety and risk of nurse prescribing of ionising radiation are socially constructed according to the vantage point of the professional and may not reflect objective measures of safety. These findings need to be considered more broadly in the context of ideological barriers to expanding the role of nurses

    Development of an on-disc isothermal in vitro amplification and detection of bacterial RNA

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    This document is the Accepted Manuscript version, made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/). The final, published version is available online at doi: https://doi.org/10.1016/j.snb.2016.08.018. Published by Elsevier B. V.We present a centrifugal microfluidic “Lab-on-a-Disc” (LoaD) system capable of implementing nucleic acid in vitro amplification using non-contact heating and fluorescence detection. The system functionality is verified by implementing a Nucleic Acid Sequence Based Amplification (NASBA) reaction, targeting the tmRNA transcript of Haemophilus influenzae. The NASBA assay incorporates fluorescent molecular beacon probes reporting target tmRNA amplification for endpoint detection. The system implements non-contact IR heating to heat the NASBA reaction to the required target temperatures during denaturation and amplification steps. The LoaD control system facilitates spin speed and chamber positioning for heating and fluorescence detection. The LoaD alignment system uses magnetic fields to locate and lock the chamber in the required position (heating or detection). The NASBA assay was implemented on the system using Haemophilus influenzae tmRNA over the range 102–104 cell equivalent (CE) units. For comparison, identical qNASBA assays were implemented on a Roche LightCycler 2.0 over this concentration range.Peer reviewe

    Developing outcome, process and balancing measures for an emergency department longitudinal patient monitoring system using a modified Delphi

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    Early warning score systems have been widely recommended for use to detect clinical deterioration in patients. The Irish National Emergency Medicine Programme has developed and piloted an emergency department specific early warning score system. The objective of this study was to develop a consensus among frontline healthcare staff, quality and safety staff and health systems researchers regarding evaluation measures for an early warning score system in the Emergency Department

    Solvent-selective routing for centrifugally automated solid-phase purification of RNA

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    The final publication is available at Springer via https://doi.org/10.1007/s10404-014-1477-9.We present a disc-based module for rotationally controlled solid-phase purification of RNA from cell lysate. To this end, multi-stage routing of a sequence of aqueous and organic liquids into designated waste and elution reservoirs is implemented by a network of strategically placed, solvent-selective composite valves. Using a bead-based stationary phase at the entrance of the router, we show that total RNA is purified with high integrity from cultured MCF7 and T47D cell lines, human leucocytes and Haemophilus influenzae cell lysates. Furthermore, we demonstrate the broad applicability of the device through the in vitro amplification of RNA purified on-disc using RT-PCR and NASBA. Our novel router will be at the pivot of a forthcoming, fully integrated and automated sample preparation system for RNA-based analysis.Peer reviewe
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