252 research outputs found

    USE OF CHAMBERLAIN FIXED EFFECTS APPROACH TO ESTIMATE WILLINGNESS-TO-PAY FOR LITTLE TENNESSEE RIVER BASIN MANAGEMENT ALTERNATIVES

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    The paper discusses an application of Chamberlain's fixed effects model to contingent valuation method survey data obtained for eight management alternatives for the Little Tennessee River basin. The advantages of using this approach versus cross-sectional logit, pooled logit, and cross-sectional logit with lags are discussed and a technique to obtain willingness-to-pay estimates from estimated coefficients is offered. Drawbacks of using Chamberlain's fixed effects model, difficulties encountered, and directions for further research are presented.Environmental Economics and Policy,

    Discerning Aggregation in Homogeneous Ensembles: A General Description of Photon Counting Spectroscopy in Diffusing Systems

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    In order to discern aggregation in solutions, we present a quantum mechanical analog of the photon statistics from fluorescent molecules diffusing through a focused beam. A generating functional is developed to fully describe the experimental physical system as well as the statistics. Histograms of the measured time delay between photon counts are fit by an analytical solution describing the static as well as diffusing regimes. To determine empirical fitting parameters, fluorescence correlation spectroscopy is used in parallel to the photon counting. For expedient analysis, we find that the distribution's deviation from a single Poisson shows a difference between two single fluor moments or a double fluor aggregate of the same total intensities. Initial studies were performed on fixed-state aggregates limited to dimerization. However preliminary results on reactive species suggest that the method can be used to characterize any aggregating system.Comment: 30 pages, 5 figure

    Rapid analysis of Förster resonance energy transfer by two-color global fluorescence correlation spectroscopy: Trypsin proteinase reaction

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    AbstractIn this study we introduce the combination of two-color global fluorescence correlation spectroscopy (2CG-FCS) and Förster resonance energy transfer (FRET) as a very powerful combination for monitoring biochemical reactions on the basis of single molecule events. 2CG-FCS, which is a new variation emerging from the family of fluorescence correlation spectroscopy, globally analyzes the simultaneously recorded auto- and cross-correlation data from two photon detectors monitoring the fluorescence emission of different colors. Overcoming the limitations inherent in mere auto- and cross-correlation analysis, 2CG-FCS is sensitive in resolving and quantifying fluorescent species that differ in their diffusion characteristics and/or their molecular brightness either in one or both detection channels. It is able to account for effects that have often been considered as sources of severe artifacts in two-color and FRET measurements, the most prominent artifacts comprising photobleaching, cross talk, or concentration variations in sample preparation. Because of its very high statistical accuracy, the combination of FRET and 2CG-FCS is suited for high-throughput applications such as drug screening. Employing beam scanning during data acquisition even further enhances this capability and allows measurement times of <2s. The improved performance in monitoring a FRET sample was verified by following the protease cleavage reaction of a FRET-active peptide. The FRET-inactive subpopulation of uncleaved substrate could be correctly assigned, revealing a substantial portion of inactive or missing acceptor label. The results were compared to those obtained by two-dimensional fluorescence intensity distribution analysis

    Further validation of the Toronto extremity salvage score for lower extremity soft tissue sarcoma based on Finnish patients

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    The most widely used patient-reported outcome (PRO) measure for soft tissue sarcoma (STS) patients is the Toronto Extremity Salvage Score (TESS). The aim of the study was to validate and test the reliability of the TESS for patients with lower extremity STS based on Finnish population data. Patients were assessed using the TESS, the QLQ-C30 Function and Quality of life (QoL) modules, the 15D and the Musculoskeletal tumour Society (MSTS) score. The TESS was completed twice with a 2- to 4-week interval. The intraclass correlation coefficient (ICC) was used for test-retest reliability. Construct validity was tested for structural validity and convergent validity. Altogether 136 patients completed the TESS. A ceiling effect was noted as 21% of the patients scored maximum points. The ICC between first and second administration of the TESS was 0.96. The results of exploratory factor analysis together with high Cronbach's alpha (0.98) supported a unidimensional structure. The TESS correlated moderately with the MSTS score (rho = 0.59, p < 0.001) and strongly with the mobility dimension in the 15D HRQL instrument (rho = 0.76, p < 0.001) and the physical function in QLQ-C30 (rho = 0.83, p < 0.001). The TESS instrument is a comprehensive and reliable PRO measure. The TESS may be used as a validated single index score, for lower extremity STS patients for the measurement of a functional outcome. The TESS seems to reflect patients' HRQoL well after the treatment of lower extremity soft tissue sarcomas. (C) 2020 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

    Measuring functional outcome in upper extremity soft-tissue sarcoma : Validation of the Toronto extremity salvage score and the QuickDASH patient-reported outcome instruments

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    Interest in functional outcome (FO) and health-related quality of life (HRQL) in extremity soft-tissue sarcoma (STS) patients has increased. The aim of this study was to validate two FO questionnaires for upper extremity STS patients: the Toronto Extremity Salvage Score (TESS) and short version of the Disability of Arm, Shoulder and Hand (QuickDASH), based on Finnish population data. A multi-center study was conducted at two academic sarcoma centers. Surgically treated upper extremity STS patients were invited to participate. Patients completed the TESS and the QuickDASH with HRQL questionnaires the 15D and the QLQ-C30. The scores were analyzed and compared. Fifty-five patients with a mean follow-up period of 4.7 years were included. Mean age was 63 years (standard deviation [SD] 14.6). The mean score for TESS was 88.5 (SD 15.1) and for QuickDASH 17.8 (SD 19.6). The QuickDASH had a statistically significantly better score coverage. A ceiling effect was noted, 27% and 20% for TESS and QuickDASH, respectively. The TESS and QuickDASH scores were strongly correlated ( r =-0.89). The TESS score strongly correlated with the QLQ-C30 ( r = 0.79) and the 15D score ( r = 0.70). The QuickDASH score correlated strongly with the QLQ-C30 score ( r =-0.71) and moderately with the 15D score ( r =-0.56). The TESS score had a statistically significantly stronger correlation with the 15D score than QuickDASH ( p < 0.005). Both the TESS and the QuickDASH provide reliable scores for assessing FO in upper extremity STS patients. The QuickDASH has a better coverage, whereas TESS showed a stronger correlation to HRQL scores. (c) 2022 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )Peer reviewe

    Charting the reach and contribution of IMP literature in other disciplines: A bibliometric analysis

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThe acknowledgement of a research tradition by other disciplines shows its contribution to the development of the broader body of scientific knowledge. This paper investigates the contribution of IMP (Industrial Marketing and Purchasing) research to broader research disciplines by analyzing how researchers within and beyond IMP have cited core IMP articles. First, through quantitative bibliometric analysis, the paper identifies the diffusion to other research disciplines. Thereafter, through qualitative analysis, the impact of the IMP perspective is captured to understand how strong these imprints are. The analyses show that IMP research has been noticed among a range of adjacent research disciplines. However, the use of IMP references has generally been rudimentary, and without a deeper understanding of the IMP ontology, meaning that IMP still has some “weak ties” to the other disciplines. Establishing IMP's contribution through enduring imprints would need further engagement with researchers from other research disciplines and publications in top journals. The paper contributes empirically with how the IMP perspective has spread beyond the IMP Group and theoretically by adding insight into how research ideas travel and transform to other disciplines

    Variants Near MC4R Are Associated With Obesity and Influence Obesity-Related Quantitative Traits in a Population of Middle-Aged People: Studies of 14,940 Danes

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    OBJECTIVE— Variants downstream of the melanocortin-4 receptor gene (MC4R) have been reported to associate with obesity. We examined rs17782313, rs17700633, rs12970134, rs477181, rs502933, and rs4450508 near MC4R for association with obesity-related quantitative traits, obesity, and type 2 diabetes in Danish individuals

    Explore the concept of “light” and its interaction with matter: an inquiry-based science education project in primary school

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    The exploration process leading to the understanding of physical phenomena, such as light and its interaction with matter, raises great interest and curiosity in children. However, in most primary schools, children rarely have the opportunity to conduct science activities in which they can engage in an enquiry process even if by the action of the teacher. In this context, we have organised several in-service teacher training courses and carried out several pedagogic interventions in Portuguese primary schools, with the aim of promoting inquirybased science education. This article describes one of those projects, developed with a class of the third grade, which explored the curricular topic “Light Experiments”. Various activities were planned and implemented, during a total of ten hours spread over five lessons. The specific objectives of this paper are: to illustrate and analyse the teaching and learning process promoted in the classroom during the exploration of one of these lessons, and to assess children’s learning three weeks after the lessons. The results suggest that children made significant learning which persisted. We conclude discussing some processes that stimulated children’ learning, including the importance of teacher questioning in scaffolding children's learning and some didactic implications for teacher training.CIEC – Research Centre on Child Studies, IE, UMinho (FCT R&D unit 317), Portuga

    Resolving fluorescent species by their brightness and diffusion using correlated photon-counting histograms

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    Fluorescence fluctuation spectroscopy (FFS) refers to techniques that analyze fluctuations in the fluorescence emitted by fluorophores diffusing in a small volume and can be used to distinguish between populations of molecules that exhibit differences in brightness or diffusion. For example, fluorescence correlation spectroscopy (FCS) resolves species through their diffusion by analyzing correlations in the fluorescence over time; photon counting histograms (PCH) and related methods based on moment analysis resolve species through their brightness by analyzing fluctuations in the photon counts. Here we introduce correlated photon counting histograms (cPCH), which uses both types of information to simultaneously resolve fluorescent species by their brightness and diffusion. We define the cPCH distribution by the probability to detect both a particular number of photons at the current time and another number at a later time. FCS and moment analysis are special cases of the moments of the cPCH distribution, and PCH is obtained by summing over the photon counts in either channel. cPCH is inherently a dual channel technique, and the expressions we develop apply to the dual colour case. Using simulations, we demonstrate that two species differing in both their diffusion and brightness can be better resolved with cPCH than with either FCS or PCH. Further, we show that cPCH can be extended both to longer dwell times to improve the signal-to-noise and to the analysis of images. By better exploiting the information available in fluorescence fluctuation spectroscopy, cPCH will be an enabling methodology for quantitative biology
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