The Strong Running Coupling from an Approximate Gluon Dyson-Schwinger Equation

Using Mandelstam's approximation to the gluon Dyson-Schwinger equation we calculate the gluon self-energy in a renormalisation group invariant fashion. We obtain a non-perturbative $\beta$ function. The scaling behaviour near the ultraviolet stable fixed point is in good agreement with perturbative QCD. No further fixed point for positive values of the coupling is found: $\alpha_S$ increases without bound in the infrared.Comment: 4 pages, 3 figures, Contribution to the Workshop ''Quark Confinement and the Hadron Spectrum II'', Como, Italy, June 26--29, 1996, to appear in the Proceedings, ed. Nora Brambilla, World Scientifi

Geographic bias related to geocoding in epidemiologic studies

BACKGROUND: This article describes geographic bias in GIS analyses with unrepresentative data owing to missing geocodes, using as an example a spatial analysis of prostate cancer incidence among whites and African Americans in Virginia, 1990–1999. Statistical tests for clustering were performed and such clusters mapped. The patterns of missing census tract identifiers for the cases were examined by generalized linear regression models. RESULTS: The county of residency for all cases was known, and 26,338 (74%) of these cases were geocoded successfully to census tracts. Cluster maps showed patterns that appeared markedly different, depending upon whether one used all cases or those geocoded to the census tract. Multivariate regression analysis showed that, in the most rural counties (where the missing data were concentrated), the percent of a county's population over age 64 and with less than a high school education were both independently associated with a higher percent of missing geocodes. CONCLUSION: We found statistically significant pattern differences resulting from spatially non-random differences in geocoding completeness across Virginia. Appropriate interpretation of maps, therefore, requires an understanding of this phenomenon, which we call "cartographic confounding.

Ring-Pattern Dynamics in Smectic-C* and Smectic-C_A* Freely Suspended Liquid Crystal Films

Ring patterns of concentric 2pi-solitons in molecular orientation, form in freely suspended chiral smectic-C films in response to an in-plane rotating electric field. We present measurements of the zero-field relaxation of ring patterns and of the driven dynamics of ring formation under conditions of synchronous winding, and a simple model which enables their quantitative description in low polarization DOBAMBC. In smectic C_A* TFMHPOBC we observe an odd-even layer number effect, with odd number layer films exhibiting order of magnitude slower relaxation rates than even layer films. We show that this rate difference is due to much larger spontaneous polarization in odd number layer films.Comment: 4 RevTeX pgs, 4 eps figures, submitted to Phys. Rev. Let

National trends in emergency readmission rates: A longitudinal analysis of administrative data for England between 2006 and 2016

Objective To assess trends in 30-day emergency readmission rates across England over one decade. Design Retrospective study design. Setting 150 non-specialist hospital trusts in England. Participants 23 069 134 patients above 18 years of age who were readmitted following an initial admission (n=62 584 297) between April 2006 and February 2016. Primary and secondary outcomes We examined emergency admissions that occurred within 30 days of discharge from hospital (‘emergency readmissions’) as a measure of healthcare quality. Presented are overall readmission rates, and disaggregated by the nature of the indexed admission, including whether it was elective or emergency, and by clinical health condition recorded. All rates were risk-adjusted for patient age, gender, ethnicity, socioeconomic status, comorbidities and length of stay. Results The average risk-adjusted, 30-day readmission rate increased from 6.56% in 2006/2007 to 6.76% (P<0.01) in 2012/2013, followed by a small decrease to 6.64% (P<0.01) in 2015/2016. Emergency readmissions for patients discharged following elective procedures decreased by 0.13% (P<0.05), whereas those following emergency admission increased by 1.27% (P<0.001). Readmission rates for hip or knee replacements decreased (−1.29%; P<0.001); for acute myocardial infarction (−0.04%; P<0.49), stroke (+0.62%; P<0.05), chronic obstructive pulmonary disease (+0.41%; P<0.05) and heart failure (+0.15%; P<0.05) remained stable; and for pneumonia (+2.72%; P<0.001), diabetes (+7.09%; P<0.001), cholecystectomy (+1.86%; P<0.001) and hysterectomy (+2.54%; P<0.001) increased. Conclusions Overall, emergency readmission rates in England remained relatively stable across the observation period, with trends of slight increases contained post 2012/2013. However, there were large variations in trends across clinical areas, with some experiencing marked increases in readmission rates. This highlights the need to better understand variations in outcomes across clinical subgroups to allow for targeted interventions that will ensure highest standards of care provided for all patients

Methodology to Promote Physical Activity Monitoring Adherence in Youth with Autism Spectrum Disorder

Background: Objective physical activity (PA) monitoring via accelerometry is both costly and time consuming. Furthermore, overall adherence to a monitoring protocol is often complicated by disability. Therefore it is essential that strategies for supporting accelerometer wear for youth with disabilities are maximized. The purpose of this perspective was to provide researchers a set of efficacious PA monitoring strategies based on the retrospective examination of support methodology on adherence rates for youth with Autism Spectrum Disorder (ASD). Method: Accelerometer data was collected for 163 participants with ASD in three independent cohorts. Each cohort was provided a varying set of support strategies to help maximize adherence. Chi-square analysis was used to determine differences in adherence between each cohort.Results: Adherence rates significantly increased from 51.9% in cohort 1 to 88.7% in cohort 2 [X2(1) =18.333, p<0.001] and again from 88.7% in cohort 2 to 97.4% in cohort 3 [X2(1) =2.663, p=0.103]. The greatest increase in adherence was observed from 51.9% in cohort 1 to 97.4% in cohort 3 [X2(1) =19.837, p<0.001]. Support strategies associated with these increases included: 1) social story; 2) incentive; 3) concealing techniques; and 4) 24 hrs/day wear instructions. Conclusions: Adherence to PA measurement increased when additional support strategies were utilized in combination with a traditional protocol. We recommend these support methodology be considered as preliminary best-practices when measuring objective PA in youth with ASD with likely success in other disability populations

Secondary metabolite profiling of the model legume Lotus japonicus during its symbiotic interaction with Mesorhizobium loti

Plant secondary metabolites, particularly flavonoids, are key components in the early stages of nitrogen-fixing symbiosis. Despite their importance, the endogenous secondary metabolites involved in symbiosis have not yet been identified in the model legume Lotus japonicus. We therefore determined changes in the secondary metabolic profile of Lotus japonicus roots in response to its symbiont. Analysis of the root secondary metabolite profiles 1 week after inoculation with Mesorhizobium loti revealed quantitative changes in the level of 14 phenolic peaks when compared with non-inoculated control plants. These changes affected compounds from most phenolic classes, possibly resulting from interconversion between classes since the total phenolic level remained constant. In addition, the use of 2 M. loti strains differing only in their capacity to synthesise Nod factor revealed that, although Nod factor signalling induced accumulation of a specific subset of 4 phenolic peaks, most changes were induced in response to both rhizobial strains.NR was supported by a Training Network funded by the European Training Network EU-RTN-LOTUS-HPRN-CT-2000-00086. KJW was supported by core funding from the Biotechnology and Biological Science Research Council (BBSRC), UK.Peer Reviewe

Laser frequency combs for astronomical observations

A direct measurement of the universe's expansion history could be made by observing in real time the evolution of the cosmological redshift of distant objects. However, this would require measurements of Doppler velocity drifts of about 1 centimeter per second per year, and astronomical spectrographs have not yet been calibrated to this tolerance. We demonstrate the first use of a laser frequency comb for wavelength calibration of an astronomical telescope. Even with a simple analysis, absolute calibration is achieved with an equivalent Doppler precision of approximately 9 meters per second at about 1.5 micrometers - beyond state-of-the-art accuracy. We show that tracking complex, time-varying systematic effects in the spectrograph and detector system is a particular advantage of laser frequency comb calibration. This technique promises an effective means for modeling and removal of such systematic effects to the accuracy required by future experiments to see direct evidence of the universe's putative acceleration.Comment: Science, 5th September 2008. 18 pages, 7 figures (7 JPG files), including Supporting Online Material. Version with higher resolution figures available at http://astronomy.swin.edu.au/~mmurphy/pub.htm

The White Dwarf Distance to the Globular Cluster 47 Tucanae and its Age

We present a new determination of the distance (and age) of the Galactic globular cluster 47 Tucanae (NGC 104) based on the fit of its white dwarf (WD) cooling sequence with the empirical fiducial sequence of local WD with known trigonometric parallax, following the method described in Renzini et al. (1996). Both the cluster and the local WDs were imaged with HST+WFPC2 using the same instrument setup. We obtained an apparent distance modulus of $(m-M)_V=13.27\pm0.14$ consistent with previous ground-based determinations and shorter than that found using HIPPARCOS subdwarfs. Coupling our distance determination with a new measure of the apparent magnitude of the main sequence turnoff, based on our HST data, we derive an age of $13\pm2.5$ Gyr.Comment: Accepted for publication on the Astrophysical Journa

Determining the Physical Properties of the B Stars I. Methodology and First Results

We describe a new approach to fitting the UV-to-optical spectra of B stars to model atmospheres and present initial results. Using a sample of lightly reddened stars, we demonstrate that the Kurucz model atmospheres can produce excellent fits to either combined low dispersion IUE and optical photometry or HST FOS spectrophotometry, as long as the following conditions are fulfilled: 1) an extended grid of Kurucz models is employed, 2) the IUE NEWSIPS data are placed on the FOS absolute flux system using the Massa & Fitzpatrick (1999) transformation, and 3) all of the model parameters and the effects of interstellar extinction are solved for simultaneously. When these steps are taken, the temperatures, gravities, abundances and microturbulence velocities of lightly reddened B0-A0 V stars are determined to high precision. We also demonstrate that the same procedure can be used to fit the energy distributions of stars which are reddened by any UV extinction curve which can be expressed by the Fitzpatrick & Massa (1990) parameterization scheme. We present an initial set of results and verify our approach through comparisons with angular diameter measurements and the parameters derived for an eclipsing B star binary. We demonstrate that the metallicity derived from the ATLAS 9 fits to main sequence B stars is essentially the Fe abundance. We find that a near zero microturbulence velocity provides the best-fit to all but the hottest or most luminous stars (where it may become a surrogate for atmospheric expansion), and that the use of white dwarfs to calibrate UV spectrophotometry is valid.Comment: 17 pages, including 2 pages of Tables and 6 pages of Figures. Astrophysical Jounral, in pres

A Model for Professional Inquiry-based Education: Lessons from Construction Management Toward Further Research

Having implemented new curricula built around inquiry-based coursework, two construction management programs compared their two curricula to establish common challenges. To develop further research, it appeared that a theoretical model was needed to define characteristic problems and potentials of professional inquiry-based education. A model is a conceptual tool that provides a structure of relationships for the development of research designs. This paper describes the development of that model and how it helps define the shared challenges between the two programs. These challenges are then investigated in terms of potential research questions, issues that help focus research plans, and initial ideas about theory and data collection. Key Words: Inquiry-based learning, construction management education, curriculum design, professional education. Introduction The construction management programs at California Polytechnic State University at San Luis Obispo and Mississippi State University have worked over the past decade to implement new curricula built around inquirybased coursework. These changes reflected what both programs saw as problems in traditional construction education; that the development of integrative, problem-solving, and thinking skills was too difficult in lecture course -silos,‖ and that new pedagogic methods were needed to respond to the unprecedented changes occurring in contemporary construction practice. Supported by the research literature in education, both programs instituted fiveand six-credit problem-solving courses around which each new curriculum was structured. In these courses-called -labs‖ and -studios‖-students engage multivariate construction problems through strategies of proposition, reflection, and solution iteration. Students are active learners and develop master-apprentice relationships with faculty. Skills, knowledge, and critical thinking are built through repeated exposure to more difficult and demanding problems. While still rare in construction education, both universities independently arrived at the same conclusion: inquiry-based learning holds tremendous potential for educating twenty-first century construction professionals. In the continuing work of rebuilding their curriculums, Cal Poly and Mississippi State conducted a comparison of their two programs to establish common challenges that could be addressed by researc