Concern for the patient’s experience comes of age

In this special guest editorial for the inaugural issue of Patient Experience Journal. Dr. Press reflects on how the focus on patient experience has evolved. He starts with a reflection, A journal devoted exclusively to the patient’s experience? A patient satisfaction survey mandated by CMS for all hospitals and a portion of reimbursement dependent upon the scores? An Institute and an “Association” addressing Patient Experience? A new hospital administrative position labeled “Chief Experience Officer”? Some 30 years ago no one would have predicted any of these. Dr. Press helps us explore and review how the patient experience movement has evolved and the implications of both our history and current state on how we address patient and family needs moving forward. He aptly offers in closing, Concern for the patient’s experience is coming of age

The SuperCOSMOS Sky Survey. Paper III: Astrometry

In this, the third in a series of three papers concerning the SuperCOSMOS Sky Survey, we describe the astrometric properties of the database. We describe the algorithms employed in the derivation of the astrometric parameters of the data, and demonstrate their accuracies by comparison with external datasets using the first release of data, the South Galactic Cap survey. We show that the celestial coordinates, which are tied to the International Celestial Reference Frame via the Tycho-2 reference catalogue, are accurate to better than +/- 0.2 arcsec at J,R=19,18 rising to +/- 0.3 arcsec at J,R=22,21 with positional dependent systematic effects from bright to faint magnitudes at the +/- 0.1 arcsec level. The proper motion measurements are shown to be accurate to typically +/- 10 mas/yr at J,R=19,18 rising to +/- 50 mas/yr at J,R=22,21 and are tied to zero using the extragalactic reference frame. We show that the zeropoint errors in the proper motions are 17 and are no larger than 10 mas/yr for R < 17 mas/yr.Comment: 15 pages, 12 figures; accepted for publication in MNRA

Correcting the influence of an asymmetric line spread function in 2-degree Field spectrograph data

We investigate the role of asymmetries in the line spread function of the 2-degree field spectrograph and the variations in these asymmetries with the CCD, the plate, the time of observation and the fibre. A data-reduction pipeline is developed that takes these deformations into account for the calibration and cross-correlation of the spectra. We show that, using the emission lines of calibration lamp observations, we can fit the line spread function with the sum of two Gaussian functions representing the theoretical signal and a perturbation of the system. This model is then used to calibrate the spectra and generate templates by downgrading high resolution spectra. Thus, we can cross-correlate the observed spectra with templates degraded in the same way. Our reduction pipeline is tested on real observations and provides a significant improvement in the accuracy of the radial velocities obtained. In particular, the systematic errors that were as high as ~20 km/s when applying the AAO reduction package 2dfDR are now reduced to ~5 km/s. Even though the 2-degree Field spectrograph is to be decommissioned at the end of 2005, the analysis of archival data and previous studies could be improved by the reduction procedure we propose here.Comment: 9 pages, 9 figures, accepted to PASA, minor change

Transit Detection in the MEarth Survey of Nearby M Dwarfs: Bridging the Clean-First, Search-Later Divide

In the effort to characterize the masses, radii, and atmospheres of potentially habitable exoplanets, there is an urgent need to find examples of such planets transiting nearby M dwarfs. The MEarth Project is an ongoing effort to do so, as a ground-based photometric survey designed to detect exoplanets as small as 2 Earth radii transiting mid-to-late M dwarfs within 33 pc of the Sun. Unfortunately, identifying transits of such planets in photometric monitoring is complicated both by the intrinsic stellar variability that is common among these stars and by the nocturnal cadence, atmospheric variations, and instrumental systematics that often plague Earth-bound observatories. Here we summarize the properties of MEarth data gathered so far, and we present a new framework to detect shallow exoplanet transits in wiggly and irregularly-spaced light curves. In contrast to previous methods that clean trends from light curves before searching for transits, this framework assesses the significance of individual transits simultaneously while modeling variability, systematics, and the photometric quality of individual nights. Our Method for Including Starspots and Systematics in the Marginalized Probability of a Lone Eclipse (MISS MarPLE) uses a computationally efficient semi-Bayesian approach to explore the vast probability space spanned by the many parameters of this model, naturally incorporating the uncertainties in these parameters into its evaluation of candidate events. We show how to combine individual transits processed by MISS MarPLE into periodic transiting planet candidates and compare our results to the popular Box-fitting Least Squares (BLS) method with simulations. By applying MISS MarPLE to observations from the MEarth Project, we demonstrate the utility of this framework for robustly assessing the false alarm probability of transit signals in real data. [slightly abridged]Comment: accepted to the Astronomical Journal, 21 pages, 12 figure

Stellar Photometry and Astrometry with Discrete Point Spread Functions

The key features of the MATPHOT algorithm for precise and accurate stellar photometry and astrometry using discrete Point Spread Functions are described. A discrete Point Spread Function (PSF) is a sampled version of a continuous PSF which describes the two-dimensional probability distribution of photons from a point source (star) just above the detector. The shape information about the photon scattering pattern of a discrete PSF is typically encoded using a numerical table (matrix) or a FITS image file. Discrete PSFs are shifted within an observational model using a 21-pixel-wide damped sinc function and position partial derivatives are computed using a five-point numerical differentiation formula. Precise and accurate stellar photometry and astrometry is achieved with undersampled CCD observations by using supersampled discrete PSFs that are sampled 2, 3, or more times more finely than the observational data. The precision and accuracy of the MATPHOT algorithm is demonstrated by using the C-language MPD code to analyze simulated CCD stellar observations; measured performance is compared with a theoretical performance model. Detailed analysis of simulated Next Generation Space Telescope observations demonstrate that millipixel relative astrometry and millimag photometric precision is achievable with complicated space-based discrete PSFs. For further information about MATPHOT and MPD, including source code and documentation, see http://www.noao.edu/staff/mighell/matphotComment: 19 pages, 22 figures, accepted for publication in MNRA

Microlensing induced spectral variability in Q2237+0305

We present both photometry and spectra of the individual images of the quadruple gravitational lens system Q2237+0305. Comparison of spectra obtained at two epochs, separated by $\sim~3\,$years, shows evidence for significant changes in the emission line to continuum ratio of the strong ultraviolet CIV~$\lambda$1549, CIII]~$\lambda$1909 and MgII~$\lambda$2798 lines. The short, $\sim~1\,$day, light--travel time differences between the sight lines to the four individual quasar images rule out any explanation based on intrinsic variability of the source. The spectroscopic differences thus represent direct detection of microlensing--induced spectroscopic differences in a quasar. The observations allow constraints to be placed on the relative spatial scales in the nucleus of the quasar, with the ultra--violet continuum arising in a region of \la~0.05~{\rm pc} in extent, while the broad emission line material is distributed on scales much greater than this.Comment: Accepted for Publication in MNRAS. Paper with 11 figure

Unambiguous quasar microlensing

Microlensing studies of quasars can reveal dark matter lumps over a broad mass spectrum; we highlight the importance of monitoring quasars which are seen through the halos of low-redshift galaxies. For these configurations microlensing by planetary-mass objects will manifest itself as isolated events which are only weakly chromatic. Statistical comparison of the observed optical depths with their theoretical counterparts provides a strong test for a microlensing origin of such events. If microlensing is detected, the light-curves can reveal not only the characteristic microlens masses, and their corresponding contribution to dark halos, but also how compact the individual objects are. In this way we can decisively test the possibility that the dark matter associated with galaxies is composed principally of planetary-mass gas clouds.Comment: Revised version; 5 pages, 4 figures, to appear in MNRA

The Upper Atmosphere of HD17156b

HD17156b is a newly-found transiting extrasolar giant planet (EGP) that orbits its G-type host star in a highly eccentric orbit (e~0.67) with an orbital semi-major axis of 0.16 AU. Its period, 21.2 Earth days, is the longest among the known transiting planets. The atmosphere of the planet undergoes a 27-fold variation in stellar irradiation during each orbit, making it an interesting subject for atmospheric modelling. We have used a three-dimensional model of the upper atmosphere and ionosphere for extrasolar gas giants in order to simulate the progress of HD17156b along its eccentric orbit. Here we present the results of these simulations and discuss the stability, circulation, and composition in its upper atmosphere. Contrary to the well-known transiting planet HD209458b, we find that the atmosphere of HD17156b is unlikely to escape hydrodynamically at any point along the orbit, even if the upper atmosphere is almost entirely composed of atomic hydrogen and H+, and infrared cooling by H3+ ions is negligible. The nature of the upper atmosphere is sensitive to to the composition of the thermosphere, and in particular to the mixing ratio of H2, as the availability of H2 regulates radiative cooling. In light of different simulations we make specific predictions about the thermosphere-ionosphere system of HD17156b that can potentially be verified by observations.Comment: 31 pages, 42 eps figure

The Binary Fraction of Low Mass White Dwarfs

We describe spectroscopic observations of 21 low-mass (<0.45 M_sun) white dwarfs (WDs) from the Palomar-Green Survey obtained over four years. We use both radial velocities and infrared photometry to identify binary systems, and find that the fraction of single, low-mass WDs is <30%. We discuss the potential formation channels for these single stars including binary mergers of lower-mass objects. However, binary mergers are not likely to explain the observed number of single low-mass WDs. Thus additional formation channels, such as enhanced mass loss due to winds or interactions with substellar companions, are likely.Comment: 9 pages, accepted to Ap

A catalogue of rotation and activity in early-M stars

We present a catalogue of rotation and chromospheric activity in a sample of 334 M dwarfs of spectral types M0--M4.5 populating the parameter space around the boundary to full convection. We obtained high-resolution optical spectra for 206 targets and determined projected rotational velocity, vsini, and Halpha emission. The data are combined with measurements of vsini in field stars of the same spectral type from the literature. Our sample adds 157 new rotation measurements to the existing literature and almost doubles the sample of available vsini. The final sample provides a statistically meaningful picture of rotation and activity at the transition to full convection in the solar neighborhood. We confirm the steep rise in the fraction of active stars at the transition to full convection known from earlier work. In addition, we see a clear rise in rotational velocity in the same stars. In very few stars, no chromospheric activity but a detection of rotational broadening was reported. We argue that all of them are probably spurious detections; we conclude that in our sample all significantly rotating stars are active, and all active stars are significantly rotating. The rotation-activity relation is valid in partially and in fully convective stars. Thus, we do not observe any evidence for a transition from a rotationally dominated dynamo in partially convective stars to a rotation-independent turbulent dynamo in fully convective stars; turbulent dynamos in fully convective stars of spectral types around M4 are still driven by rotation. Finally, we compare projected rotational velocities of 33 stars to rotational periods derived from photometry in the literature and determine inclinations for a few of them.Comment: accepted for publication in A