886 research outputs found

    Transition from electron accumulation to depletion at InGaN surfaces

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    The composition dependence of the Fermi-level pinning at the oxidized (0001) surfaces of n-type InxGa1−xN films (0<=x<=1) is investigated using x-ray photoemission spectroscopy. The surface Fermi-level position varies from high above the conduction band minimum (CBM) at InN surfaces to significantly below the CBM at GaN surfaces, with the transition from electron accumulation to depletion occurring at approximately x=0.3. The results are consistent with the composition dependence of the band edges with respect to the charge neutrality level

    Intercomparisons of Aura MLS, ACE, and HALOE Observations of Long-Lived Trace Species Using the Langley Lagrangian Chemistry and Transport Model

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    We use the LaRC Lagrangian Chemistry and Transport Model (LCTM) [Considine et al., 2007; Pierce et al., 2003] to intercompare ACE, Aura, and HALOE observations of long-lived trace species. The LCTM calculates the transport, mixing, and photochemical evolution of an ensemble of parcels that have been initialized from ACE-FTS measurements. Here we focus on late November, 2004 comparisons, due to the previous 3-week period of continuous HALOE observations and MLS v2.2 data on November 29, 2004

    Proinsulin Secretion Is a Persistent Feature of Type 1 Diabetes

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    OBJECTIVE: Abnormally elevated proinsulin secretion has been reported in type 2 and early type 1 diabetes when significant C-peptide is present. We questioned whether individuals with long-standing type 1 diabetes and low or absent C-peptide secretory capacity retained the ability to make proinsulin. RESEARCH DESIGN AND METHODS: C-peptide and proinsulin were measured in fasting and stimulated sera from 319 subjects with long-standing type 1 diabetes (≥3 years) and 12 control subjects without diabetes. We considered three categories of stimulated C-peptide: 1) C-peptide positive, with high stimulated values ≥0.2 nmol/L; 2) C-peptide positive, with low stimulated values ≥0.017 but <0.2 nmol/L; and 3) C-peptide <0.017 nmol/L. Longitudinal samples were analyzed from C-peptide-positive subjects with diabetes after 1, 2, and 4 years. RESULTS: Of individuals with long-standing type 1 diabetes, 95.9% had detectable serum proinsulin (>3.1 pmol/L), while 89.9% of participants with stimulated C-peptide values below the limit of detection (<0.017 nmol/L; n = 99) had measurable proinsulin. Proinsulin levels remained stable over 4 years of follow-up, while C-peptide decreased slowly during longitudinal analysis. Correlations between proinsulin with C-peptide and mixed-meal stimulation of proinsulin were found only in subjects with high stimulated C-peptide values (≥0.2 nmol/L). Specifically, increases in proinsulin with mixed-meal stimulation were present only in the group with high stimulated C-peptide values, with no increases observed among subjects with low or undetectable (<0.017 nmol/L) residual C-peptide. CONCLUSIONS: In individuals with long-duration type 1 diabetes, the ability to secrete proinsulin persists, even in those with undetectable serum C-peptide

    Implementation of a hospital-wide multidisciplinary blunt chest injury care bundle (ChIP): Fidelity of delivery evaluation

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    BackgroundIneffective intervention for patients with blunt chest wall injury results in high rates of morbidity and mortality. To address this, a blunt chest injury care bundle protocol (ChIP) was developed, and a multifaceted plan was implemented using the Behaviour Change Wheel.ObjectiveThe purpose of this study was to evaluate the reach, fidelity, and dose of the ChIP intervention to discern if it was activated and delivered to patients as intended at two regional Australian hospitals.MethodsThis is a pretest and post-test implementation evaluation study. The proportion of ChIP activations and adherence to ChIP components received by eligible patients were compared before and after intervention over a 4-year period. Sample medians were compared using the nonparametric median test, with 95% confidence intervals. Differences in proportions for categorical data were compared using the two-sample z-test.Results/findingsOver the 19-month postimplementation period, 97.1% (n = 440) of eligible patients received ChIP (reach). The median activation time was 134 min; there was no difference in time to activation between business hours and after-hours; time to activation was not associated with comorbidities and injury severity score. Compared with the preimplementation group, the postimplementation group were more likely to receive evidence-based treatments (dose), including high-flow nasal cannula use (odds ratio [OR] = 6.8 [95% confidence interval {CI} = 4.8-9.6]), incentive spirometry in the emergency department (OR = 7.5, [95% CI = 3.2-17.6]), regular analgesia (OR = 2.4 [95% CI = 1.5-3.8]), regional analgesia (OR = 2.8 [95% CI = 1.5-5.3]), patient-controlled analgesia (OR = 1.8 [95% CI = 1.3-2.4]), and multiple specialist team reviews, e.g., surgical review (OR = 9.9 [95% CI = 6.1-16.1]).ConclusionsHigh fidelity of delivery was achieved and sustained over 19 months for implementation of a complex intervention in the acute context through a robust implementation plan based on theoretical frameworks. There were significant and sustained improvements in care practices known to result in better patient outcomes. Findings from this evaluation can inform future implementation programs such as ChIP and other multidisciplinary interventions in an emergency or acute care context

    Corner Exponents in the Two-Dimensional Potts Model

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    The critical behavior at a corner in two-dimensional Ising and three-state Potts models is studied numerically on the square lattice using transfer operator techniques. The local critical exponents for the magnetization and the energy density for various opening angles are deduced from finite-size scaling results at the critical point for isotropic or anisotropic couplings. The scaling dimensions compare quite well with the values expected from conformal invariance, provided the opening angle is replaced by an effective one in anisotropic systems.Comment: 11 pages, 2 eps-figures, uses LaTex and eps
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