219 research outputs found

    Developmental Changes in Synaptic Function in a Giant Auditory Synapse

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    Developmental Changes in Synaptic Function in a Giant Auditory Synapse

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    Responses of Syrphids, Elaterids and Bees to Single-tree Selection Harvesting in Algonquin Provincial Park, Ontario

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    The species composition of hoverflies (Syrphidae), click beetles (Elateridae), and bees (Apoidea) was studied to determine whether there was a positive response in these flower-seeking insect groups to gaps in the canopy created through single-tree selection harvesting of Sugar Maple (Acer saccharum) and Yellow Birch (Betula alleghaniensis) in hardwood forests of the Great Lakes-St. Lawrence forest region of Algonquin Provincial Park, Ontario. There were significantly more hoverflies and bees collected in forest stands harvested within the previous five years than in wilderness zone (unharvested at least for 40 years) stands or stands harvested 15-20 years previously (old logged stands). Click beetles, especially Selatosomus pulcher (LeConte), were collected most often in old logged stands. Bees and click beetles were collected significantly later in the season in logged than in wilderness zone stands. Malaise traps resulted in higher capture rates for syrphids than pan traps, and only with these higher capture rates did we detect a significant increase in species richness in recently logged stands over that in wilderness stands. Changes in the numbers and phenology of flower-visiting insects may impact on reproductive success of flowering plants of the forest understory and deserves further study

    PROMIS Physical Function short forms display item- and scale-level characteristics at least as good as the Roland Morris Disability Questionnaire in patients with chronic low back pain

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    OBJECTIVE: To compare dimensionality, item-level characteristics, scale-level reliability and construct validity of PROMIS® Physical Function short forms (PROMIS-PF) and 24-item Roland Morris Disability Questionnaire (RMDQ-24) in patients with chronic low back pain (LBP). DESIGN: Cross-sectional study. SETTING: Secondary care center for rehabilitation and rheumatology. PARTICIPANTS: Patients with non-specific LBP ≥ 3 months (n = 768). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Dutch versions of the 4-, 6-, 8-, 10- and 20-item PROMIS-PF, and of the RMDQ-24. RESULTS: Mean age was 49 years (±13), 77% female, 54% displayed pain for more than 5 years. PROMIS-PF-6, PROMIS-PF-8 and RMDQ-24 exhibited sufficient unidimensionality (confirmatory factor analysis: CFI >0.950, TLI >0.950 and RMSEA 0.001). Two-parameter item response theory models found two items with low discrimination for RMDQ-24. All other instruments had adequate fit statistics and item parameters. PROMIS-PF-20 displayed the best scale-level reliability. Construct validity was sufficient for all instruments as all hypotheses on expected correlations with other instruments, and differences between relevant subgroups, were met. CONCLUSIONS: PROMIS-PF-6, PROMIS-PF-8 and RMDQ-24 exhibited better unidimensionality, whereas PROMIS-PF-4, PROMIS-PF-6 PROMIS-PF-8 and PROMIS-PF-10 showed superior item-level characteristics. PROMIS-PF-20 was the instrument with the best scale-level reliability. This study warrants assessment of other measurement properties of PROMIS-PF short forms in comparison to disease-specific physical functioning instruments in LBP

    First Validation of the Full PROMIS Pain Interference and Pain Behavior Item Banks in Patients With Rheumatoid Arthritis

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    Objective: Pain interference and pain behavior are highly relevant outcomes in patients with rheumatoid arthritis (RA). The Patient-Reported Outcomes Measurement Information System (PROMIS) is a universally applicable set of item banks measuring patient-reported health, and if applied as computerized adaptive tests (CATs), more efficiently and precisely than current instruments. The objective was to study the psychometric properties of the Dutch-Flemish PROMIS pain interference (PROMIS-PI) and the PROMIS pain behavior (PROMIS-PB) item banks in patients with RA. Methods: A total of 2,029 patients with RA completed the full PROMIS-PI (version 1.1, 40 items), and 1,554 patients completed the full PROMIS-PB (version 1.1, 39 items). The following psychometric properties were studied: unidimensionality, local dependence, monotonicity and graded response model (GRM) fit, cross-cultural validity (differential item functioning [DIF] for language [Dutch versus Flemish]), other forms of measurement invariance, construct validity, reliability, and floor and ceiling effects. Results: The PROMIS-PI and PROMIS-PB banks were sufficiently unidimensional (Omega-hierarchical [Omega-H] 0.99, 0.95, and explained common variance 0.95, 0.78, respectively), had negligible local dependence (0.3–1.4% of item pairs), good monotonicity (H 0.75, 0.46), and a good GRM model fit (no misfitting items). Furthermore, both item banks showed good cross-cultural validity (no DIF for language), measurement invariance (no DIF for age, sex, administration mode, and disease activity), good construct validity (all hypotheses met), high reliability (>0.90 in the range of patients with RA), and an absence of floor and ceiling effects (0% minimum or maximum score, respectively). Conclusion: Both PROMIS-PI and PROMIS-PB banks showed good psychometric properties in patients with RA and can be used as CATs in research and clinical practice

    Influence of Scanner Precision and Analysis Software in Quantifying Three-Dimensional Intraoral Changes: Two-Factor Factorial Experimental Design

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    Background: Three-dimensional scans are increasingly used to quantify biological topographical changes and clinical health outcomes. Traditionally, the use of 3D scans has been limited to specialized centers owing to the high cost of the scanning equipment and the necessity for complex analysis software. Technological advances have made cheaper, more accessible methods of data capture and analysis available in the field of dentistry, potentially facilitating a primary care system to quantify disease progression. However, this system has yet to be compared with previous high-precision methods in university hospital settings. Objective: The aim of this study was to compare a dental primary care method of data capture (intraoral scanner) with a precision hospital-based method (laser profilometer) in addition to comparing open source and commercial software available for data analysis. Methods: Longitudinal dental wear data from 30 patients were analyzed using a two-factor factorial experimental design. Bimaxillary intraoral digital scans (TrueDefinition, 3M, UK) and conventional silicone impressions, poured in type-4 dental stone, were made at both baseline and follow-up appointments (mean 36 months, SD 10.9). Stone models were scanned using precision laser profilometry (Taicaan, Southampton, UK). Three-dimensional changes in both forms of digital scans of the first molars (n=76) were quantitatively analyzed using the engineering software Geomagic Control (3D Systems, Germany) and freeware WearCompare (Leeds Digital Dentistry, UK). Volume change (mm3) was the primary measurement outcome. The maximum point loss (μm) and the average profile loss (μm) were also recorded. Data were paired and skewed, and were therefore compared using Wilcoxon signed-rank tests with Bonferroni correction. Results: The median (IQR) volume change for Geomagic using profilometry and using the intraoral scan was –0.37 mm3 (–3.75-2.30) and +0.51 mm3 (–2.17-4.26), respectively (P<.001). Using WearCompare, the median (IQR) volume change for profilometry and intraoral scanning was –1.21 mm3 (–3.48-0.56) and –0.39 mm3 (–3.96-2.76), respectively (P=.04). WearCompare detected significantly greater volume loss than Geomagic regardless of scanner type. No differences were observed between groups with respect to the maximum point loss or average profile loss. Conclusions: As expected, the method of data capture, software used, and measurement metric all significantly influenced the measurement outcome. However, when appropriate analysis was used, the primary care system was able to quantify the degree of change and can be recommended depending on the accuracy needed to diagnose a condition. Lower-resolution scanners may underestimate complex changes when measuring at the micron level
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