570 research outputs found
TASS Mark IV Photometric Survey of the Northern Sky
The Amateur Sky Survey (TASS) is a loose confederation of amateur and
professional astronomers. We describe the design and construction of our Mark
IV systems, a set of wide-field telescopes with CCD cameras which take
simultaneous images in the and passbands. We explain our
observational procedures and the pipeline which processes and reduces the
images into lists of stellar positions and magnitudes. We have compiled a large
database of measurements for stars in the northern celestial hemisphere with
-band magnitudes in the range 7 < V < 13. This paper describes data taken
over the four-year period starting November, 2001. One of our results is a
catalog of repeated measurements on the Johnson-Cousins system for over 4.3
million stars.Comment: Accepted for publication in December, 2006, issue of PASP. 44 pages
including 20 figures. Patches catalog available at
http://spiff.rit.edu/tass/patches
The Amateur Sky Survey Mark III Project
The Amateur Sky Survey (TASS) is a loose confederation of amateur and
professional astronomers. We describe the design and construction of our Mark
III system, a set of wide-field drift-scan CCD cameras which monitor the
celestial equator down to thirteenth magnitude in several passbands. We explain
the methods by which images are gathered, processed, and reduced into lists of
stellar positions and magnitudes. Over the period October, 1996, to November,
1998, we compiled a large database of photometric measurements. One of our
results is the "tenxcat" catalog, which contains measurements on the standard
Johnson-Cousins system for 367,241 stars; it contains links to the light curves
of these stars as well.Comment: 20 pages, including 4 figures; additional JPEG files for Figures 1,
2. Submitted to PAS
Feasibility of an Automated Telephone Survey to Enable Prospective Monitoring of Subjects Whose Confidentiality is Paramount: a Four-week Cohort Study of Partner Violence Recurrence After Emergency Department Discharge
OBJECTIVE: A goal in intimate partner violence (IPV) research is to identify victims when they are treated in a hospital Emergency Department (ED) and predict which patients will sustain abuse again after discharge, so interventions can be targeted. Following patients to determine those prognostic factors is difficult, however, especially to study IPV given the risk to be assaulted if their partner learns of their participation. We assessed the feasibility of an automated telephone survey and a wireless incentive delivery system to follow ED patients after discharge, enabling detection of IPV recurrence.
METHODS: A four-week prospective cohort pilot study was conducted at an urban academic medical center ED in the U.S. Thirty patient subjects (24 women, 6 men; 18-54 years) who had sustained IPV in the past six months, 12 of whom presented for an acute IPV-related condition, were interviewed in the ED and were asked to report weekly for four weeks after discharge to a toll-free, password protected telephone survey, and answer recorded questions using the telephone keypad. A 10 for each weekly report, with a $20 bonus for making all four reports.
RESULTS: Twenty-two of 30 subjects (73.3%) made at least one report to the telephone survey during the four weeks following discharge; 14 of the 30 subjects (46.7%) made all four weekly reports. Each time the telephone survey was accessed, the subject completed all questions (i.e., no mid-survey break-offs). Eight months after follow-up ended, almost all debit cards (86.7%) had been used to make purchases.
CONCLUSION: Approximately three of every four subjects participated in follow-up after ED discharge, and approximately two of every four subjects completed all follow-up reports, suggesting the method of an automated telephone survey and wireless incentive delivery system makes it feasible to study IPV prospectively among discharged patients. That finding, along with evidence that IPV recurrence risk is high, suggests the protocol tested is warranted for use conducting full-scale studies of IPV. The protocol could benefit efforts to study other outcomes, especially when patient confidentiality is paramount for their safety
Characterizing the 18 April 2002 stormâtime sawtooth events using ground magnetic data
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95189/1/jgra17938.pd
The effectiveness, safety and cost-effectiveness of cytisine versus varenicline for smoking cessation in an Australian population: a study protocol for a randomized controlled non-inferiority trial
Smoking cessation medications are effective but often underutilised because of costs and side effects. Cytisine is a plant-based smoking cessation medication with over 50 years of use in Central and Eastern Europe. While cytisine has been found to be well-tolerated and more effective than nicotine replacement therapy, direct comparison with varenicline have not been conducted. This study evaluates the effectiveness, safety and cost-effectiveness of cytisine compared with varenicline.Two arm, parallel group, randomised, non-inferiority trial, with allocation concealment and blinded outcome assessment.Australian population-based study.Adult daily smokers (N=1266) interested in quitting will be recruited through advertisements and Quitline telephone-based cessation support services.Eligible participants will be randomised (1:1 ratio) to receive either cytisine capsules (25-day supply) or varenicline tablets (12-week supply), prescribed in accordance with the manufacturer's recommended dosing regimen. The medication will be mailed to each participant's nominated residential address. All participants will also be offered standard Quitline behavioural support (up to six 10-12 minute sessions).Assessments will be undertaken by telephone at baseline, 4- and 7-months post-randomisation. Participants will also be contacted twice (two and four weeks post-randomisation) to ascertain adverse events, treatment adherence and smoking status. The primary outcome will be self-reported 6-month continuous abstinence from smoking, verified by carbon monoxide at 7-month follow-up. We will also evaluate the relative safety and cost-effectiveness of cytisine compared with varenicline. Secondary outcomes will include self-reported continuous and 7-day point prevalence abstinence and cigarette consumption at each follow-up interview.If cytisine is as effective as varenicline, its lower cost and natural plant-based composition may make it an acceptable and affordable smoking cessation medication that could save millions of lives worldwide
A Large, Uniform Sample of X-ray Emitting AGN from the ROSAT All-Sky and Sloan Digital Sky Surveys: the Data Release 5 Sample
We describe further results of a program aimed to yield ~10^4 fully
characterized optical identifications of ROSAT X-ray sources. Our program
employs X-ray data from the ROSAT All-Sky Survey (RASS), and both optical
imaging and spectroscopic data from the Sloan Digital Sky Survey (SDSS).
RASS/SDSS data from 5740 deg^2 of sky spectroscopically covered in SDSS Data
Release 5 (DR5) provide an expanded catalog of 7000 confirmed quasars and other
AGN that are probable RASS identifications. Again in our expanded catalog, the
identifications as X-ray sources are statistically secure, with only a few
percent of the SDSS AGN likely to be randomly superposed on unrelated RASS
X-ray sources. Most identifications continue to be quasars and Seyfert 1s with
15<m<21 and 0.01<z<4; but the total sample size has grown to include very
substantial numbers of even quite rare AGN, e.g., now including several
hundreds of candidate X-ray emitting BL Lacs and narrow-line Seyfert 1
galaxies. In addition to exploring rare subpopulations, such a large total
sample may be useful when considering correlations between the X-ray and the
optical, and may also serve as a resource list from which to select the "best"
object (e.g., X-ray brightest AGN of a certain subclass, at a preferred
redshift or luminosity) for follow-on X-ray spectral or alternate detailed
studies.Comment: Accepted for publication in AJ; 32 pages, including 11 figures, and 6
example table
The u'g'r'i'z' Standard Star Network
We present the 158 standard stars that define the u'g'r'i'z' photometric
system. These stars form the basis for the photometric calibration of the Sloan
Digital Sky Survey (SDSS). The defining instrument system and filters, the
observing process, the reduction techniques, and the software used to create
the stellar network are all described. We briefly discuss the history of the
star selection process, the derivation of a set of transformation equations for
the UBVRcIc system, and plans for future work.Comment: References to URLs in paper have been updated to reflect moved
website. Accepted by AJ. 50 pages, including 20 pages of text, 9 tables, and
15 figures. Plain ASCII text versions of Tables 8 and 9 can be found at
http://home.fnal.gov/~dtucker/ugriz/index.html (new URL
BVRI Photometry of Supernovae
We present optical photometry of one Type IIn supernova (1994Y) and nine Type
Ia supernovae (1993Y, 1993Z, 1993ae, 1994B, 1994C, 1994M, 1994Q, 1994ae, and
1995D). SN 1993Y and SN 1993Z appear to be normal SN Ia events with similar
rates of decline, but we do not have data near maximum brightness. The colors
of SN 1994C suggest that it suffers from significant reddening or is
intrinsically red. The light curves of SN 1994Y are complicated; they show a
slow rise and gradual decline near maximum brightness in and numerous
changes in the decline rates at later times. SN 1994Y also demonstrates color
evolution similar to that of the SN IIn 1988Z, but it is slightly more luminous
and declines more rapidly than SN 1988Z. The behavior of SN1994Y indicates a
small ejecta mass and a gradual strengthening of the H emission
relative to the continuum.Comment: 29 pages, 10 jpg figures, 6 eps figures, 8 tables; note added in
proo
Two More Candidate AM Canum Venaticorum (AM CVn) Binaries from the Sloan Digital Sky Survey
AM CVn systems are a select group of ultracompact binaries with the shortest
orbital periods of any known binary subclass; mass-transfer is likely from a
low-mass (partially-)degenerate secondary onto a white dwarf primary, driven by
gravitational radiation. In the past few years, the Sloan Digital Sky Survey
(SDSS) has provided five new AM CVns. Here we report on two further candidates
selected from more recent SDSS data. SDSS J1208+3550 is similar to the earlier
SDSS discoveries, recognized as an AM CVn via its distinctive spectrum which is
dominated by helium emission. From the expanded SDSS Data Release 6 (DR6)
spectroscopic area, we provide an updated surface density estimate for such AM
CVns of order 10^{-3.1} to 10^{-2.5} per deg^2 for 15<g<20.5. In addition, we
present another new candidate AM CVn, SDSS J2047+0008, that was discovered in
the course of followup of SDSS-II supernova candidates. It shows nova-like
outbursts in multi-epoch imaging data; in contrast to the other SDSS AM CVn
discoveries, its (outburst) spectrum is dominated by helium absorption lines,
reminiscent of KL Dra and 2003aw. The variability selection of SDSS J2047+0008
from the 300 deg^2 of SDSS Stripe 82 presages further AM CVn discoveries in
future deep, multicolor, and time-domain surveys such as LSST. The new
additions bring the total SDSS yield to seven AM CVns thus far, a substantial
contribution to this rare subclass, versus the dozen previously known.Comment: 19 pages, 5 figures, 1 table; submitted to A
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