Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682) I. Memberships, Binaries, and Kinematics

(Abridged) We present results from 13776 radial-velocity (RV) measurements of 1278 candidate members of the old (4 Gyr) open cluster M67 (NGC 2682). The measurements are the results of a long-term survey that includes data from seven telescopes with observations for some stars spanning over 40 years. For narrow-lined stars, RVs are measured with precisions ranging from about 0.1 to 0.8 km/s. The combined stellar sample reaches from the brightest giants in the cluster down to about 4 magnitudes below the main-sequence turnoff (V = 16.5), covering a mass range of about 1.34 MSun to 0.76 MSun. Spatially, the sample extends to a radius of 30 arcmin (7.4 pc in projection at a distant of 850 pc or 6-7 core radii). We find M67 to have a mean RV of +33.64 km/s (with an internal precision of +/- 0.03 km/s). For stars with >=3 measurements, we derive RV membership probabilities and identify RV variables, finding 562 cluster members, 142 of which show significant RV variability. We use these cluster members to construct a color-magnitude diagram and identify a rich sample of stars that lie far from the standard single star isochrone, including the well-known blue stragglers, sub-subgiants and yellow giants. These exotic stars have a binary frequency of (at least) 80%, more than three times that detected for stars in the remainder of the sample. We confirm that the cluster is mass segregated, finding the binaries to be more centrally concentrated than the single stars in our sample at the 99.8% confidence level. The blue stragglers are centrally concentrated as compared to the solar-type main-sequence single stars in the cluster at the 99.7% confidence level. Accounting for both measurement precision and undetected binaries, we derive a RV dispersion in M67 of 0.59 +0.07 -0.06 km/s, which yields a virial mass for the cluster of 2100 +610 -550 MSun. WIYN Open Cluster Study. LXVII.Comment: 19 pages, 10 figures, 4 tables, accepted for publication in The Astronomical Journa

The precision of experienced action video-game players: Line bisection reveals reduced leftward response bias

Twenty-two experienced action video-game players (AVGPs) and 18 non-VGPs were tested on a pen-and-paper line bisection task that was untimed. Typically, right-handers bisect lines 2 % to the left of true centre, a bias thought to reflect the dominance of the right-hemisphere for visuospatial attention. Expertise may affect this bias, with expert musicians showing no bias in line bisection performance. Our results show that experienced-AVGPs also bisect lines with no bias with their right hand and a significantly reduced bias with their left hand compared to non-AVGPs. Bisections by experienced-AVGPs were also more precise than those of non-AVGPs. These findings show the cognitive proficiencies of experienced-AVGPs can generalize beyond computer based tasks, which resemble their training environment

Detection of Planetary Transits Across a Sun-like Star

We report high precision, high cadence photometric measurements of the star HD 209458, which is known from radial velocity measurements to have a planetary mass companion in a close orbit. We detect two separate transit events at times that are consistent with the radial velocity measurements. In both cases, the detailed shape of the transit curve due to both the limb darkening of the star and the finite size of the planet is clearly evident. Assuming stellar parameters of 1.1 R_Sun and 1.1 M_Sun, we find that the data are best interpreted as a gas giant with a radius of 1.27 +/- 0.02 R_Jup in an orbit with an inclination of 87.1 +/- 0.2 degrees. We present values for the planetary surface gravity, escape velocity, and average density, and discuss the numerous observations that are warranted now that a planet is known to transit the disk of its parent star.Comment: 10 pages, 3 figures, accepted by ApJ Letter

Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073–2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127–135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260–1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and atomic number (Z) reconstructions to a significant extent.S.J.L., G.R.M., and A.M.K. acknowledge funding through the DigiCore consortium and the support of a linkage grant (LP150101040) from the Australian Research Council and FEI Company

Case study based approach to integration of sustainable design analysis, performance and building information modelling

This paper presents a case study based research of both the method and technology for integration of sustainable design analysis (SDA) and building information modelling (BIM) within smart built environments (SBE). Level 3 BIM federation and integration challenges are recognised and improvements suggested, including issues with combining geometry and managing attribute data. The research defines SDA as rapid and quantifiable analysis of diverse sustainable alternatives and ‘what if’ scenarios posed by a design team and client during the early stages of the project, where the benefits of correct decisions can significantly exceed the actual investment required. The SDA concept and BIM integration findings are explained through a convergence from conceptualisation to calculation stages, emphasising the importance of an iterative over a linear approach. The approach allowed for a multitude of “what if” scenarios to be analysed, leading to more informed sustainable solutions at the right stages of the project development, with a generally lower level of detail (LOD) and computational/modelling effort required. In addition, the final stage of Building Regulations Part L compliance calculations was reached with a lot greater level of certainty, in terms of its requirements. Finally, a strategy for long term performance monitoring and evaluation of the building design in terms of its environmental sustainability is presented, via integration between BIM and SBE (Smart Built Environment) technologies

Peer coaching through mHealth targeting physical activity in people with Parkinson disease: feasibility study

BACKGROUND: Long-term engagement in exercise and physical activity mitigates the progression of disability and increases quality of life in people with Parkinson disease (PD). Despite this, the vast majority of individuals with PD are sedentary. There is a critical need for a feasible, safe, acceptable, and effective method to assist those with PD to engage in active lifestyles. Peer coaching through mobile health (mHealth) may be a viable approach. OBJECTIVE: The purpose of this study was to develop a PD-specific peer coach training program and a remote peer-mentored walking program using mHealth technology with the goal of increasing physical activity in persons with PD. We set out to examine the feasibility, safety, and acceptability of the programs along with preliminary evidence of individual-level changes in walking activity, self-efficacy, and disability in the peer mentees. METHODS: A peer coach training program and a remote peer-mentored walking program using mHealth was developed and tested in 10 individuals with PD. We matched physically active persons with PD (peer coaches) with sedentary persons with PD (peer mentees), resulting in 5 dyads. Using both Web-based and in-person delivery methods, we trained the peer coaches in basic knowledge of PD, exercise, active listening, and motivational interviewing. Peer coaches and mentees wore FitBit Zip activity trackers and participated in daily walking over 8 weeks. Peer dyads interacted daily via the FitBit friends mobile app and weekly via telephone calls. Feasibility was determined by examining recruitment, participation, and retention rates. Safety was assessed by monitoring adverse events during the study period. Acceptability was assessed via satisfaction surveys. Individual-level changes in physical activity were examined relative to clinically important differences. RESULTS: Four out of the 5 peer pairs used the FitBit activity tracker and friends function without difficulty. A total of 4 of the 5 pairs completed the 8 weekly phone conversations. There were no adverse events over the course of the study. All peer coaches were "satisfied" or "very satisfied" with the training program, and all participants were "satisfied" or "very satisfied" with the peer-mentored walking program. All participants would recommend this program to others with PD. Increases in average steps per day exceeding the clinically important difference occurred in 4 out of the 5 mentees. CONCLUSIONS: Remote peer coaching using mHealth is feasible, safe, and acceptable for persons with PD. Peer coaching using mHealth technology may be a viable method to increase physical activity in individuals with PD. Larger controlled trials are necessary to examine the effectiveness of this approach.This study is supported by Boston Roybal Center for Active Lifestyle Interventions (RALI Boston), Grant #P30 AG048785, and the American Parkinson Disease Association, Massachusetts chapter. The authors would like to thank Nicole Sullivan, SOT, for her assistance with data management and data collection and Nick Wendel, DPT, for his assistance with data collection. Additionally, the authors would like to thank the participants in this study for their time, effort, and insights. (P30 AG048785 - Boston Roybal Center for Active Lifestyle Interventions (RALI Boston); American Parkinson Disease Association, Massachusetts chapter)Accepted manuscrip

Efficient operation of a high-power X-band gyroklystron

Experimental studies of amplification in a two-cavity X-band gyroklystron are reported. The system utilizes a thermionic magnetron injection gun at voltages up to 440 kV and currents up to 190 A in 1-μs pulses. Optimum performance is achieved by tapering the magnetic-field profile. Peak powers of 20 MW in the TE01 mode at 9.87 GHz are measured with calibrated crystals and with methanol calorimetry. Resultant efficiencies are in excess of 31% and large-signal gains surpass 26 dB. The experimental results are in good agreement with simulated results from a partially self-consistent, nonlinear, steady-state code

Visual acuity standards for driving

This paper reviews the current visual acuity standards for UK drivers. These standards have changed in recent years such that car drivers (Group 1) now have two standards to meet: reading a number plate at 20m, and achieving an acuity of 6/12. In the light of these changes, research investigating the effect of uncorrected refractive error and simulated cataract on the ability to meet the visual standards is reviewed, as is the effect of reduced contrast sensitivity on driving. On the basis of these findings, recommendations are made for optometrists regarding how to assess acuity in drivers, and how to use this information when advising patients on their visual fitness to drive

Does neighborhood disorder predict recovery from mobility limitation? Findings from the Health and Retirement Study

Objective: This research explores whether perceptions of physical neighborhood disorder predict recovery from mobility limitation over a 2-year period and examines whether psychosocial factors (i.e., depressive symptomology and mastery) and physical activity are salient mediators. Method: Using data from the Health and Retirement Study (HRS): Participant Lifestyle Questionnaire (2008-2010), odds ratio estimates of recovery were ascertained using binary logistic regression, and post hoc Sobel tests were conducted to formally assess mediation. Results: Net of demographic characteristics and socioeconomic status, increased neighborhood disorder was associated with lower odds of recovery. However, both psychosocial indicators and physical activity were significant individual partial mediators, which suggest neighborhood disorder influences recovery from physical impairment via psychosocial processes and barriers to physical activity. Discussion: Reducing neighborhood disorder may enhance older residents’ psychosocial well-being and improve participation in physical activity, thus increasing recovery from mobility limitation and preventing subsequent disability