237 research outputs found

    OrganiZational communication and organiSational communication: Binaries and the fragments of a field

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    In this paper, I employ personal narrative to help cast light on connections and tensions between organiZational communication research, as produced in the United States, and organiSational communication research, as produced in Aotearoa New Zealand. I address the issue by highlighting three sets of differences between these bodies of research: canonical, institutional and theoretical. I then unpack how these differences are apparent in my own university before sketching out three ways in which we might productively use such tensions to achieve radical engagement, and critique disciplinary others, identities, and locations

    3,5-Dithiatricyclo[5.2.1.02,6]decan-2-one

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    The X-ray structure of the title compound has been determined and the structure shows an exo-configured planar dithiolanone ring. This is in contrast to the few previous dithiolanones to be characterised crystallographically which are all twisted.Publisher PDFPeer reviewe

    Taxonomy, location of origin, and health status of proboscideans from Western Canada investigated using stable isotope analysis

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    We investigated the application of stable isotope analysis of proboscidean remains (collagen in bone/dentin/cementum and structural carbonate in enamel bioapatite) for genus-level identification of isolated specimens, assessment of geographic origins, and testing for nutritional stress. Mammoths (Mammuthus sp.) tended to have higher δ15Ncol and lower δ13Ccol than mastodons (Mammut americanum), but differences were not significant in every location. Determining the genus of isolated specimens may be possible for locations and time periods with good isotopic baselines, but environmental changes can confound interpretations. For example, an Alberta proboscidean with a δ15Ncol of +1.4‰ (characteristic of mastodons) ultimately proved to be a mammoth. Its surprisingly low nitrogen isotope composition is attributable to the recently deglaciated environment it inhabited. We provided a baseline for isotopic assessment of geographic origins of isolated proboscideans in Western Canada. Bioapatite δ13Csc and δ18Osc can be used to distinguish specimens from Alberta, Klondike, Old Crow, Herschel Island, and further south (e.g., Arizona, Great Lakes). Finally, we found that an Alberta mammoth with morphological evidence of nutritional stress experienced a change in diet, environment, or physiology prior to death, but its isotopic compositions did not suggest a link to hypothesized starvation (catabolism of proteins or reliance on lipids)

    High rates of venous and arterial thrombotic events in patients with POEMS syndrome: results from the UCLH (UK) POEMS Registry

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    Arterial and venous thromboses occur in patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein level, and skin changes) syndrome at a previously reported rate of 20%. We reviewed the University College London Hospitals (UCLH) POEMS Registry to determine the rate of venous thromboembolism (VTE), arterial events, and risk factors. This registry, established in 1999 and comprising 103 patients at the time of this study, is the largest single-center cohort in Europe. Of the 83 assessable patients, median age at presentation was 52 years (range, 31-84). Twenty-five patients experienced clinically apparent arterial or venous events, and 2 had concurrent arterial and venous thromboses. Eleven patients had VTEs, including deep vein thrombosis (DVT; 3 of 11), pulmonary embolism (4 of 11), and peripherally inserted central catheter–associated DVT, which occurred during autologous stem cell transplantation (3 of 11). Sixteen patients experienced arterial events: stroke (7 of 16), peripheral arterial occlusion (5 of 16), myocardial infarction (3 of 16), and microvascular disease (1 of 16), with no discernible relationship with thrombocytosis or polycythemia. Thirty percent of POEMS patients have arterial and venous thromboses, higher than previously reported. There were more arterial than venous events, and most occurred during active disease, before the start of chemotherapy, indicating the need for a preemptive approach to thromboprophylaxi

    A diagnostic conundrum

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    A 26-year-old man was referred with facial weakness, dysarthria, dysphagia, ophthalmoparesis and severely weak and wasted legs. His symptoms had begun when aged 20 with electric shock pains and paraesthesia in both feet progressing over 6 months to the lower calves. He then developed buttock numbness and occasional faecal incontinence. By age 22, he had diffuse lower limb weakness and wasting, with difficulty standing from a seated position and frequent tripping. He became wheelchair-dependent within 3 years

    A fluorescence approach to investigate repartitioning of coalescing agents in acrylic polymer emulsions

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    Repartitioning of co-solvents between particles of latex emulsions was investigated by means of a fluorescence method based on the detection of the amount of co-solvent via the solvatochromic shift of the emission maximum of a fluorescent probe, copolymerized at a low concentration. Complete repartitioning of co-solvents between particles of latex materials with a low Tg (ca. 25 °C) occurred within minutes. For a hydrophilic latex with a Tg of 68 °C, equilibration was achieved within an hour. Repartitioning was faster for more hydrophobic co-solvents. For a hydrophobic latex of similar Tg, co-solvent repartitioning took place on the same time scale, but complete equilibration was not reached. Possibly, there is an additional slow component in the repartitioning, or the prolonged presence of co-solvent causes a structural change in the latex particles that affects the outcome of the experiment

    Temperature- and thickness-dependent elastic moduli of polymer thin films

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    The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T) and thickness (h)-dependent elastic moduli of polymer thin films Ef(T,h) is developed with verification by the reported experimental data on polystyrene (PS) thin films. For the PS thin films on a passivated substrate, Ef(T,h) decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*), at which thickness Ef(T,h) deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ

    Mechanical Properties of Glassy Polyethylene Nanofibers via Molecular Dynamics Simulations

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    The extent to which the intrinsic mechanical properties of polymer fibers depend on physical size has been a matter of dispute that is relevant to most nanofiber applications. Here, we report the elastic and plastic properties determined from molecular dynamics simulations of amorphous, glassy polymer nanofibers with diameter ranging from 3.7 to 17.7 nm. We find that, for a given temperature, the Young’s elastic modulus E decreases with fiber radius and can be as much as 52% lower than that of the corresponding bulk material. Poisson’s ratio ν of the polymer comprising these nanofibers was found to decrease from a value of 0.3 to 0.1 with decreasing fiber radius. Our findings also indicate that a small but finite stress exists on the simulated nanofibers prior to elongation, attributable to surface tension. When strained uniaxially up to a tensile strain of ε = 0.2 over the range of strain rates and temperatures considered, the nanofibers exhibit a yield stress σy between 40 and 72 MPa, which is not strongly dependent on fiber radius; this yield stress is approximately half that of the same polyethylene simulated in the amorphous bulk.DuPont MIT AllianceDuPont (Firm) (Young Professor Award
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