7,492 research outputs found

    Contributions to the Science of Environmental Impact Assessment: Three Papers on the Arctic Cisco (Coregonus autumnalis) of Northern Alaska

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    Editor's Introduction -- D. W. Norton; An Assessment of the Colville River Delta Stock of Arctic Cisco--Migrants from Canada? -- B. J. Gallaway, W. B. Griffiths, P. C. Craig, W. J. Gazey, and J. W. Helmericks; Temperature Preference of Juvenile Arctic Cisco (Coregonus autumnalis) From the Alaskan Beaufort Sea -- R. G. Fechhelm, W. H. Neill, and B. J. Gallaway; Modeling Movements and Distribution of Arctic Cisco (Coregonus autumnalis) Relative to Temperature-Salinity Regimes of the Beaufort Sea Near the Waterflood Causeway, Prudhoe Bay, Alaska. -- W. H. Neill, R. G. Fechhelm, B. J. Gallaway, J. D. Bryan, and S. W. Anderson; Notice to Author

    Scale-invariant gravity: Spacetime recovered

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    The configuration space of general relativity is superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms. However, it has been argued that the configuration space for gravity should be conformal superspace - the space of all Riemannian 3-metrics modulo diffeomorphisms and conformal transformations. Recently a manifestly 3-dimensional theory was constructed with conformal superspace as the configuration space. Here a fully 4-dimensional action is constructed so as to be invariant under conformal transformations of the 4-metric using general relativity as a guide. This action is then decomposed to a (3+1)-dimensional form and from this to its Jacobi form. The surprising thing is that the new theory turns out to be precisely the original 3-dimensional theory. The physical data is identified and used to find the physical representation of the theory. In this representation the theory is extremely similar to general relativity. The clarity of the 4-dimensional picture should prove very useful for comparing the theory with those aspects of general relativity which are usually treated in the 4-dimensional framework.Comment: Replaced with final version: minor changes to tex

    Vortices in Thin, Compressible, Unmagnetized Disks

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    We consider the formation and evolution of vortices in a hydrodynamic shearing-sheet model. The evolution is done numerically using a version of the ZEUS code. Consistent with earlier results, an injected vorticity field evolves into a set of long-lived vortices, each of which has a radial extent comparable to the local scale height. But we also find that the resulting velocity field has a positive shear stress, . This effect appears only at high resolution. The transport, which decays with time as t^-1/2, arises primarily because the vortices drive compressive motions. This result suggests a possible mechanism for angular momentum transport in low-ionization disks, with two important caveats: a mechanism must be found to inject vorticity into the disk, and the vortices must not decay rapidly due to three-dimensional instabilities.Comment: 8 pages, 10 figures (high resolution figures available in ApJ electronic edition

    From transformative learning to social change? Using action research to explore and improve informal complaints management in an NHS trust

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    Background: The number of complaints concerning aspects of care from patients and/or carers have increased over time. Yet, in spite of a growing body of national and international literature on health care complaints there is a lack of knowledge around how nurses and midwives manage informal complaints at ward level, or staff needs in relation to this. Aim: Using an Action research (AR) approach with mixed methods, four phases and four cycles, the aim was to explore informal complaints management by nurses and midwives at ward level. We discuss the AR process primarily in connection with learning and service change, drawing from the qualitative data in this paper. Findings: The analysis of the collected qualitative data resulted in three main themes related to the complexities of complaints and complaints management, staff support needs and the existing ambiguous complaints systems which are hard for both staff and servicer users to negotiate. The AR approach facilitated learning and change in participants in relation to views on complaints management, and the main issues around complaints management in the collaborating trust. Conclusions: The extant body of research on complaints does not sufficiently recognise the complexity of complaints and informal complaints management or the complaints systems in place. Needs based staff training can help support staff to manage informal complaints more effectively

    Gatekeeping access to the midwifery unit: managing complaints by bending the rules

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    While poor communication between service users and front line staff causes many service user complaints in the British National Health Service (NHS), staff rarely reflect on the causes of these complaints. We discuss findings from an action research project with midwives which suggest that the midwives struggled to fully understand complaints from women, their partners and families particularly about restricted visiting and the locked door to the midwifery unit. They responded to individual requests to visit out of hours while maintaining the general policy of restricted visiting. In this way the door was a gatekeeping device which allowed access to the unit within certain rules. The locked door remained a barrier to women and their families and as a result was a common source of informal complaints. We argue that the locked door and restricted visiting to the midwifery unit were forms of gate-keeping and boundary making by midwives which reveals a tension between their espoused woman-centred care and contemporary midwifery practice which is increasingly constrained by institutional values

    Chandra Observations of the Crab-like Supernova Remnant G21.5-0.9

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    Chandra observations of the Crab-like supernova remnant G21.5-0.9 reveal a compact central core and spectral variations indicative of synchrotron burn-off of higher energy electrons in the inner nebula. The central core is slightly extended, perhaps indicating the presence of an inner wind-shock nebula surrounding the pulsar. No pulsations are observed from the central region, yielding an upper limit of ~40% for the pulsed fraction. A faint outer shell may be the first evidence of the expanding ejecta and blast wave formed in the initial explosion, indicating a composite nature for G21.5-0.9.Comment: 4 pages, 2 figures, formatted with emulateapj, submitted to ApJ

    Fault-Tolerant Thresholds for Encoded Ancillae with Homogeneous Errors

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    I describe a procedure for calculating thresholds for quantum computation as a function of error model given the availability of ancillae prepared in logical states with independent, identically distributed errors. The thresholds are determined via a simple counting argument performed on a single qubit of an infinitely large CSS code. I give concrete examples of thresholds thus achievable for both Steane and Knill style fault-tolerant implementations and investigate their relation to threshold estimates in the literature.Comment: 14 pages, 5 figures, 3 tables; v2 minor edits, v3 completely revised, submitted to PR

    Mechanisms Regulating the Association of Protein Phosphatase 1 with Spinophilin and Neurabin

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    Protein phosphorylation is a key mediator of signal transduction, allowing for dynamic regulation of substrate activity. Whereas protein kinases obtain substrate specificity by targeting specific amino acid sequences, serine/threonine phosphatase catalytic subunits are much more promiscuous in their ability to dephosphorylate substrates. To obtain substrate specificity, serine/threonine phosphatases utilize targeting proteins to regulate phosphatase subcellular localization and catalytic activity. Spinophilin and its homologue neurabin are two of the most abundant dendritic spine-localized protein phosphatase 1 (PP1) targeting proteins. The association between spinophilin and PP1 is increased in the striatum of animal models of Parkinson's disease (PD). However, mechanisms that regulate the association of spinophilin and neurabin with PP1 are unclear. Here, we report that the association between spinophilin and PP1α or PP1γ1 was increased by CDK5 expression and activation in a heterologous cell system. This increased association is at least partially due to phosphorylation of PP1. Conversely, CDK5 expression and activation decreased the association of PP1 with neurabin. As with dopamine depletion, methamphetamine (METH) abuse causes persistent alterations in dopamine signaling which influence striatal medium spiny neuron function and biochemistry. Moreover, both METH toxicity and dopamine depletion are associated with deficits in motor control and motor learning. Pathologically, we observed a decreased association of spinophilin with PP1 in rat striatum evaluated one month following a binge METH paradigm. Behaviorally, we found that loss of spinophilin recapitulates rotarod pathology previously observed in dopamine-depleted and METH-treated animals. Together, these data have implications in multiple disease states associated with altered dopamine signaling such as PD and psychostimulant drug abuse and delineate a novel mechanism by which PP1 interactions with spinophilin and neurabin may be differentially regulated

    Supporting staff to respond effectively to informal complaints: findings from an action research study

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    Aim: to understand how nurses and midwives manage informal complaints at ward level. Background: the provision of high quality, compassionate clinical nursing and midwifery is a global priority. Complaints management systems have been established within the National Health Service (NHS) in the United Kingdom (UK) to improve patient experience yet little is known about effective responses to informal complaints in clinical practice by nurses and midwives. Design: collaborative action research. Methods: four phases of data collection and analysis relating to primarily one NHS trust during 2011-2014 including: scoping of complaints data, interviews with five service users and six key stakeholders and eight reflective discussion groups with six midwives over a period of nine months, two sessions of communications training with separate groups of midwives and one focus group with four nurses in the collaborating trust. Results: three key themes emerged from these data: multiple and domino complaints; ward staff need support; and unclear complaints systems. Conclusions: current research does not capture the complexities of complaints and the nursing and midwifery response to informal complaints. Relevance to clinical practice: robust systems are required to support clinical staff to improve their response to informal complaints and thereby improve the patient experience
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