40 research outputs found
Manufacturing processes
The following issues are covered: process development frequently lags behind material development, high fabrication costs, flex joints (bellows) - a continuing program, SRM fabrication-induced defects, and in-space assembly will require simplified design
GaiaHub: A method for combining data from the Gaia and Hubble space telescopes to derive improved proper motions for faint stars
We present GaiaHub, a publicly available tool that combines
measurements with () archival images to
derive proper motions (PMs). It increases the scientific impact of both
observatories beyond their individual capabilities. provides PMs across
the whole sky, but the limited mirror size and time baseline restrict the best
PM performance to relatively bright stars. can measure accurate PMs for
much fainter stars over a small field, but this requires two epochs of
observation which are not always available. GaiaHub yields considerably
improved PM accuracy compared to -only measurements, especially for faint
sources , requiring only a single epoch of data observed
more than years ago (before 2012). This provides considerable
scientific value especially for dynamical studies of stellar systems or
structures in and beyond the Milky Way (MW) halo, for which the member stars
are generally faint. To illustrate the capabilities and demonstrate the
accuracy of GaiaHub, we apply it to samples of MW globular clusters (GCs) and
classical dwarf spheroidal (dSph) satellite galaxies. This allows us, e.g., to
measure the velocity dispersions in the plane of the sky for objects out to and
beyond kpc. We find, on average, mild radial velocity anisotropy in
GCs, consistent with existing results for more nearby samples. We observe a
correlation between the internal kinematics of the clusters and their
ellipticity, with more isotropic clusters being, on average, more round. Our
results also support previous findings that Draco and Sculptor dSph galaxies
appear to be radially anisotropic systems.Comment: 24 pages, 18 figures. Accepted for publication in Ap
A RCT of a Transdiagnostic Internet-Delivered Treatment for Three Anxiety Disorders: Examination of Support Roles and Disorder-Specific Outcomes
BACKGROUND: Anxiety disorders share common vulnerabilities and symptoms. Disorder-specific treatment is efficacious, but few access evidence-based care. Administering transdiagnostic cognitive-behavioral therapy via the internet (iCBT) may increase access to evidence-based treatment, with a recent randomized controlled trial (RCT) providing preliminary support for this approach. This study extends those findings and aims to answer three questions: Is a transdiagnostic iCBT program for anxiety disorders efficacious and acceptable? Does it result in change for specific disorders? Can good clinical outcomes be obtained when guidance is provided via a Coach rather than a Clinician? METHOD: RCT (N = 131) comparing three groups: Clinician-supported (CL) vs. Coach-supported (CO) vs. waitlist control (Control). Individuals met DSM-IV criteria for a principal diagnosis of generalized anxiety disorder (GAD), social phobia (SP) or panic disorder with or without agoraphobia (Pan/Ag). Treatment consisted of an 8-lesson/10 week iCBT program with weekly contact from a Clinician or Coach, and follow-up at 3-months post-treatment. RESULTS: Outcomes for the pooled treatment groups (CL+CO) were superior to the Control group on measures of anxiety, depression and disability, were associated with medium to large effect sizes (Cohen's d = .76-1.44) (response rate = 89-100%), and were maintained at follow-up. Significant reductions were found on disorder-specific outcomes for each of the target diagnoses, and were associated with large effect sizes. CO participants achieved similar outcomes to CL participants at post-treatment, yet had significantly lower symptom severity scores on general anxiety, panic-disorder, depression and disability at follow-up (d = .45-.46). Seventy-four percent of CO and 76% of CL participants completed the program. Less than 70 minutes of Clinician or Coach time was required per participant during the program. DISCUSSION: This transdiagnostic iCBT course for anxiety appears to be efficacious, associated with significant change for three target disorders, and is efficacious when guided by either a Clinician or Coach. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000242022