Imaging and Nulling with the Space Interferometry Mission

We present numerical simulations for a possible synthesis imaging mode of the Space Interferometer Mission (SIM). We summarize the general techniques that SIM offers to perform imaging of high surface brightness sources, and discuss their strengths and weaknesses. We describe an interactive software package that is used to provide realistic, photometrically correct estimates of SIM performance for various classes of astronomical objects. In particular, we simulate the cases of gaseous disks around black holes in the nuclei of galaxies, and zodiacal dust disks around young stellar objects. Regarding the first, we show that a Keplerian velocity gradient of the line-emitting gaseous disk -- and thus the mass of the putative black hole -- can be determined with SIM to unprecedented accuracy in about 5 hours of integration time for objects with H_alpha surface brigthness comparable to the prototype M 87. Detections and observations of exo-zodiacal dust disks depend critically on the disk properties and the nulling capabilities of SIM. Systems with similar disk size and at least one tenth of the dust content of beta Pic can be detected by SIM at distances between 100 pc and a few kpc, if a nulling efficiency of 1/10000 is achieved. Possible inner clear regions indicative of the presence of massive planets can also be detected and imaged. On the other hand, exo-zodiacal disks with properties more similar to the solar system will not be found in reasonable integration times with SIM.Comment: 28 pages, incl. 8 postscript figures, excl. 10 gif-figures Submitted to Ap

Consumer-Directed Health Insurance vs. Managed Care: Analysis of Health Care Utilization and Expenditure Incurred by Employees in a Rural Area

Consumer-Directed Health Plans (CDHPs) are proposed as an option to control healthcare costs. No research has addressed their applicability in rural settings. This study analyzes three years (2003–2005) of healthcare expenditure and utilization incurred by two employers and a national carrier providing data from a rural state, Kentucky. The study included two measures of expenditures (health care and prescription drugs) and three measures of utilization (physician visits, hospital admissions, and hospital inpatient days). In general, the CDHP successfully controlled the growth of medical costs. These findings suggest that CDHPs may be a viable alternative benefit structure for rural employers

Odd-Order Aberration-Cancellation in Correlated-Photon Imaging

We discuss a correlated two-photon imaging apparatus that is capable of producing images that are free of the effects of odd-order aberration introduced by the optical system. We show that both quantum-entangled and classically correlated light sources are capable of producing the desired spatial-aberration cancelation

Identification of a transporter complex responsible for the cytosolic entry of nitrogen-containing bisphosphonates

Nitrogen-containing-bisphosphonates (N-BPs) are widely prescribed to treat osteoporosis and other bone-related diseases. Although previous studies established that N-BPs function by inhibiting the mevalonate pathway in osteoclasts, the mechanism by which N-BPs enter the cytosol from the extracellular space to reach their molecular target is not understood. Here we implemented a CRISPRi-mediated genome-wide screen and identified SLC37A3 (solute carrier family 37 member A3) as a gene required for the action of N-BPs in mammalian cells. We observed that SLC37A3 forms a complex with ATRAID (all-trans retinoic acid-induced differentiation factor), a previously identified genetic target of N-BPs. SLC37A3 and ATRAID localize to lysosomes and are required for releasing N-BP molecules that have trafficked to lysosomes through fluid-phase endocytosis into the cytosol. Our results elucidate the route by which N-BPs are delivered to their molecular target, addressing a key aspect of the mechanism of action of N-BPs that may have significant clinical relevance

TREC-Rio trial: a randomised controlled trial for rapid tranquillisation for agitated patients in emergency psychiatric rooms [ISRCTN44153243]

Agitated or violent patients constitute 10% of all emergency psychiatric treatment. Management guidelines, the preferred treatment of clinicians and clinical practice all differ. Systematic reviews show that all relevant studies are small and none are likely to have adequate power to show true differences between treatments. Worldwide, current treatment is not based on evidence from randomised trials. In Brazil, the combination haloperidol-promethazine is frequently used, but no studies involving this mix exist. TREC-Rio (Tranquilização Rápida-Ensaio Clínico [Translation: Rapid Tranquillisation-Clinical Trial]) will compare midazolam with haloperidol-promethazine mix for treatment of agitated patients in emergency psychiatric rooms of Rio de Janeiro, Brazil. TREC-Rio is a randomised, controlled, pragmatic and open study. Primary measure of outcome is tranquillisation at 20 minutes but effects on other measures of morbidity will also be assessed. TREC-Rio will involve the collaboration of as many health care professionals based in four psychiatric emergency rooms of Rio as possible. Because the design of this trial does not substantially complicate clinical management, and in several aspects simplifies it, the study can be large, and treatments used in everyday practice can be evaluated

The PRIMA fringe sensor unit

The Fringe Sensor Unit (FSU) is the central element of the Phase Referenced Imaging and Micro-arcsecond Astrometry (PRIMA) dual-feed facility and provides fringe sensing for all observation modes, comprising off-axis fringe tracking, phase referenced imaging, and high-accuracy narrow-angle astrometry. It is installed at the Very Large Telescope Interferometer (VLTI) and successfully servoed the fringe tracking loop during the initial commissioning phase. Unique among interferometric beam combiners, the FSU uses spatial phase modulation in bulk optics to retrieve real-time estimates of fringe phase after spatial filtering. A R=20 spectrometer across the K-band makes the retrieval of the group delay signal possible. The FSU was integrated and aligned at the VLTI in summer 2008. It yields phase and group delay measurements at sampling rates up to 2 kHz, which are used to drive the fringe tracking control loop. During the first commissioning runs, the FSU was used to track the fringes of stars with K-band magnitudes as faint as m_K=9.0, using two VLTI Auxiliary Telescopes (AT) and baselines of up to 96 m. Fringe tracking using two Very Large Telescope (VLT) Unit Telescopes (UT) was demonstrated. During initial commissioning and combining stellar light with two ATs, the FSU showed its ability to improve the VLTI sensitivity in K-band by more than one magnitude towards fainter objects, which is of fundamental importance to achieve the scientific objectives of PRIMA.Comment: 19 pages, 23 figures. minor changes and language editing. this version equals the published articl

Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review

I present a review of astrometric techniques and instrumentation utilized to search for, detect, and characterize extra-solar planets. First, I briefly summarize the properties of the present-day sample of extrasolar planets, in connection with predictions from theoretical models of planet formation and evolution. Next, the generic approach to planet detection with astrometry is described, with significant discussion of a variety of technical, statistical, and astrophysical issues to be faced by future ground-based as well as space-borne efforts in order to achieve the required degree of measurement precision. After a brief summary of past and present efforts to detect planets via milli-arcsecond astrometry, I then discuss the planet-finding capabilities of future astrometric observatories aiming at micro-arcsecond precision. Lastly, I outline a number experiments that can be conducted by means of high-precision astrometry during the next decade, to illustrate its potential for important contributions to planetary science, in comparison with other indirect and direct methods for the detection and characterization of planetary systems.Comment: 61 pages, 8 figures, PASP, accepted (October 2005 issue

Perceived Outcomes of Web-Based Modules Designed to Enhance Athletic Trainers\u27 Knowledge of Evidence-Based Practice

Context: The release of evidence-based practice (EBP) Web-based learning modules to the membership of the National Athletic Trainers\u27 Association has provided athletic trainers (ATs) the opportunity to enhance their knowledge of the various EBP concepts. Whereas increasing the knowledge of EBP among ATs is important, assessing whether this newfound knowledge is being translated into clinical practice and didactic education is crucial. Objective: To explore the effectiveness of an educational intervention regarding EBP on the didactic instruction patterns of athletic training educators and the clinical practice behaviors of clinicians. Design: Qualitative study. Setting: Individual telephone interviews. Patients or Other Participants: A total of 25 ATs (12 educators, 13 clinicians; experience as an AT = 16.00 ± 9.41 years) were interviewed. Data Collection and Analysis: We conducted 1 individual telephone interview with each participant. After transcription, the data were analyzed and coded into common themes and categories. Triangulation of the data occurred via the use of multiple researchers and member checking to confirm the accuracy of the data. Results: Participants perceived the EBP Web-based modules to produce numerous outcomes regarding education and clinical practice. These outcomes included perceived knowledge gain among participants, an increase in the importance and scope of EBP, a positive effect on educators\u27 didactic instruction patterns and on instilling value and practice of EBP among students, and an enhanced ability among clinicians to implement EBP within clinical practice. However, some clinicians reported the Web-based modules had no current effect on clinical practice. Conclusions: Although the EBP Web-based modules were successful at enhancing knowledge among ATs, translation of knowledge into the classroom and clinical practice remains limited. Researchers should aim to identify effective strategies to help ATs implement EBP concepts into didactic education and clinical practice

A single-column model intercomparison of a heavily drizzling stratocumulus-topped boundary layer

This study presents an intercomparison of single-column model simulations of a nocturnal heavily drizzling marine stratocumulus-topped boundary layer. Initial conditions and forcings are based on nocturnal flight observations off the coast of California during the DYCOMS-II field experiment. Differences in turbulent and microphysical parameterizations between models were isolated by slightly idealizing and standardizing the specification of surface and radiative fluxes. For most participating models, the case was run at both typical operational vertical resolution of about 100 m and also at high vertical resolution of about 10 m. As in prior stratocumulus intercomparisons, the simulations quickly develop considerable scatter in liquid water path (LWP) between models. However, the simulated dependence of cloud base drizzle fluxes on LWP in most models is broadly consistent with recent observations. Sensitivity tests with drizzle turned off show that drizzle substantially decreases LWP for many models. The sensitivity of entrainment rate to drizzle is more muted. Simulated LWP and entrainment are also sensitive to the inclusion of cloud droplet sedimentation. Many models underestimate the fraction of drizzle that evaporates below cloud base, which may distort the simulated feedbacks of drizzle on turbulence, entrainment, and LWP