4,980 research outputs found

    Collaborative public procurement: Institutional explanations of legitimised resistance

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    This paper reports on the barriers to regional collaborative procurement developed from an action research study of five UK public authorities in the emergency services sector. Despite political pressure to procure collaboratively, strategic avoidance responses of institutional logics and symbolic tick boxing legitimise stakeholder resistance to isomorphic forces and entrench operational barriers. The prevailing institutional logics are that regional collaborative procurement is unsuitable and risky, derived from procurement's lack of status and the emotive nature of the emergency services. Symbolic tick boxing is seen through collaboration that is limited to high profile spend categories, enabling organisations to demonstrate compliance while simultaneously retaining local decision-making for less visible, but larger areas of spend. The findings expose choice mechanisms in public procurement by exploring tensions arising from collaborative procurement strategies within, and between, organisations. Multiple stakeholders' perspectives add to current thinking on how organisations create institutional logics to avoid institutional pressure to procure collaboratively and how stakeholders legitimise their actions

    MRI: ID-Development of a Hybrid Scanning Fluorescence and Sum Frequency Spectroscopy Imaging Microscope

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    With this award from the Major Research Instrumentation program (MRI), Michael Mason and colleagues from the Department of Chemistry at the University of Maine will develop a hybrid scanning fluorescence (FL) and sum frequency (SF) spectroscopy imaging microscope. The instrument will be constructed by the addition of sample scanning and FL capability to an existing broadband SF spectrometer. The SF NIR pump source will be used to excite SF at the sample interface, while a modulated Argon ion CW laser will excite FL. These collinear sources will give rise to spatially and temporally correlated SF and FL signals which will be separated and individually detected. The instrument will simultaneously measure the fluorescence and sum frequency to yield information about the localized dynamics of a single particle, i.e. protein, and spatially correlated structural information about the bulk material containing the particle. This yields information about the interaction between the particle and the bulk not accessible by any other method. The proposal will initially investigate test projects including the study of membrane domain structure and membrane-membrane interactions, e,g., correlation of the structure and dynamics of lipid and protein molecules within planar supported lipid bilayers. Successful development of this instrument could lead to major breakthroughs in several fields ranging from surface chemistry and biophysics to nanotechnology and cellular biology

    PRELIMINARY EVALUATION OF A GRANULAR TRIMETHACARB FORMULATION FOR DETERRING GRAZING BY AMERICAN COOTS

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    In a 0.2 ha flight pen, groups of 4 American coots were tested to determine if their grazing activity could be affected by application of a registered granular-trimethacarb insecticide. In the 3 days following treatment (3 kg/ha, a.i.), grazing activity in the treated portions of the 200 m2 experimental plots was reduced an average of 47X. Overall use of the treated areas followed a similar pattern but was less consistent among groups. The addition of methylpyrazine, a strong odorant, produced a strong initial suppression of grazing activity in the treated halves of the plots. However, subsequent rain and a change in the coots\u27 grazing behavior prevented a definitive evaluation of the methylpyrazine treatment. Two birds that died during the trimethacarb-only portion of the study did not have abnormally low levels of brain cholinesterase. However, this finding does not preclude the possibility that they were unable to distinguish treated from untreated grass and consumed lethal amounts of trimethacarb. Additional investigation of methylpyrazine appears warranted; such materials may act to decrease the likelihood that birds will ingest lethal quantities of repellent

    Computer graphics interactive workshop for two-dimensional fractals

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    We present in this study an interactive computer graphics workshop for two-dimensional fractals. The workshop enables the user to learn about fractals through experimentation with the generation of Koch-like fractal curves. A variety of Koch-like fractal curves, Julia sets and the Mandelbrot set are presented as examples. Algorithms are presented for creating the Mandelbrot set and for creating Kock-like fractal curves. Keywords and Phrases: fractals, Kock-like Fractal curves, Julia sets, interactive computer graphicsU.S. Army Combat Development Experimentation Center (USACDEC) under MIPR ATEC 46-86 and in part by funds provided through the Commodore Grace Murray Hopper Research Chair in Computer Science at the Naval Postgraduate School.http://archive.org/details/computergraphicsin00masoN0003986WRDQ200N

    The discovery of 2.78 hour periodic modulation of the X-ray flux from globular cluster source Bo 158 in M31

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    We report the discovery of periodic intensity dips in the X-ray source XMMU J004314.1+410724, in the globular cluster Bo158 in M31. The X-ray flux was modulated by ~83% at a period of 2.78 hr (10017 s) in an XMM-Newton observation taken 2002 Jan 6-7. The X-ray intensity dips show no energy dependence. We detected weaker dips with the same period in observations taken 2000 June 25 (XMM-Newton) and 1991 June 26 (ROSAT/PSPC). The amplitude of the modulation has been found to be anticorrelated with source X-ray flux: it becomes lower when the source intensity rises. The energy spectrum of Bo158 was stable from observation to observation, with a characteristic cutoff at ~4-6 keV. The photo-electric absorption was consistent with the Galactic foreground value. No significant spectral changes were seen in the course of the dips. If the 2.78 hr cycle is the binary period of Bo158 the system is highly compact, with a binary separation of ~10e11 cm. The association of the source with a globular cluster, together with spectral parameters consistent with Galactic neutron star sources, suggests that X-rays are emitted by an accreting neutron star. The properties of Bo 158 are somewhat reminiscent of the Galactic X-ray sources exhibiting a dip-like modulations. We discuss two possible mechanisms explaining the energy-independent modulation observed in Bo 158: i) the obscuration of the central source by highly ionized material that scatters X-rays out of the line of sight; ii) partial covering of an extended source by an opaque absorber which occults varying fractions of the source.Comment: 10 pages, 4 figures, ApJ, submitted, uses emulateapj styl

    Novel lines of Pax6-/- embryonic stem cells exhibit reduced neurogenic capacity without loss of viability

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    <p>Abstract</p> <p>Background</p> <p>Embryonic stem (ES) cells can differentiate into all cell types and have been used extensively to study factors affecting neuronal differentiation. ES cells containing mutations in known genes have the potential to provide useful in vitro models for the study of gene function during neuronal differentiation. Recently, mouse ES cell lines lacking the neurogenic transcription factor Pax6 were reported; neurons derived from these <it>Pax6</it><sup>-/- </sup>ES cells died rapidly after neuronal differentiation in vitro.</p> <p>Results</p> <p>Here we report the derivation of new lines of <it>Pax6</it><sup>-/- </sup>ES cells and the assessment of their ability to survive and differentiate both in vitro and in vivo. Neurons derived from our new <it>Pax6</it><sup>-/- </sup>lines were viable and continued to elaborate processes in culture under conditions that resulted in the death of neurons derived from previously reported <it>Pax6</it><sup>-/- </sup>ES cell lines. The new lines of <it>Pax6</it><sup>-/-</sup>ES cells showed reduced neurogenic potential, mimicking the effects of loss of Pax6 in vivo. We used our new lines to generate <it>Pax6</it><sup>-/- </sup>↔ <it>Pax6</it><sup>+/+ </sup>chimeras in which the mutant cells survived and displayed the same phenotypes as <it>Pax6</it><sup>-/- </sup>cells in <it>Pax6</it><sup>-/- </sup>↔ <it>Pax6</it><sup>+/+ </sup>chimeras made by embryo aggregation.</p> <p>Conclusions</p> <p>We suggest that loss of Pax6 from ES cells reduces their neurogenic capacity but does not necessarily result in the death of derived neurons. We offer these new lines as additional tools for those interested in the generation of chimeras and the analysis of in vitro ES cell models of Pax6 function during neuronal differentiation, embryonic and postnatal development.</p
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