337 research outputs found
Discovery of the Optical Transient of the Gamma Ray Burst 990308
The optical transient of the faint Gamma Ray Burst 990308 was detected by the
QUEST camera on the Venezuelan 1-m Schmidt telescope starting 3.28 hours after
the burst. Our photometry gives , , , and for times ranging from 3.28 to 3.47
hours after the burst. The colors correspond to a spectral slope of close to
. Within the standard synchrotron fireball model,
this requires that the external medium be less dense than , the
electrons contain of the shock energy, and the magnetic field energy
must be less than 24% of the energy in the electrons for normal interstellar or
circumstellar densities. We also report upper limits of at 132 s
(with LOTIS), from 132-1029s (with LOTIS), at 28.2 min
(with Super-LOTIS), and a 8.5 GHz flux of at 110 days (with the
Very Large Array). WIYN 3.5-m and Keck 10-m telescopes reveal this location to
be empty of any host galaxy to and . The lack of a host
galaxy likely implies that it is either substantially subluminous or more
distant than a red shift of .Comment: ApJ Lett submitted, 5 pages, 2 figures, no space for 12 coauthor
Caregiver Comfort in Adolescents Independently Completing Screening Tablet-Based Questionnaires at Primary Care Visits
Objectives
The objective of this study was to assess caregiver comfort regarding adolescent completion of computerized health screening questionnaires created for adolescents.
Design
We conducted a mixed method, cross-sectional survey of caregivers of adolescent patients (n=104) ages 12–18 years that had a medical visit between June and August of 2017. Topics assessed included who completed the questionnaire, caregiver comfort and concern regarding questionnaire data, and caregiver reasons for involvement in completing the questionnaire. A one-way ANOVA was used to compare age of the adolescent and caregiver involvement in the questionnaire.
Results
The majority of adolescents (64%) reported independent completion of the questionnaire. Thirteen percent of caregivers completed the questionnaire with no involvement of the adolescent and 23% reported that caregivers and adolescents completed the questionnaire in tandem. The majority of caregivers (84%) were comfortable with adolescents completing the questionnaire. A variety of reasons were identified for caregivers completing the questionnaire (time constraints, 22%; adolescent requested caregiver help, 19%; caregiver desired to answer questions, 14%; caregiver did not realize that the questionnaire was intended for the adolescent, 11%; caregiver believed that the adolescent was too young to respond alone, 11%. Caregiver comfort with adolescent completing the questionnaire increase with age.
Conclusion
We found the reason most caregivers gave for completing the questionnaires were related to clinic processes (e.g. time constraints) Caregivers were more likely to complete the questionnaire with younger adolescents. Thus, pediatricians should consider how to best prepare families for initial questionnaires in primary care
The International Gene Trap Consortium Website: a portal to all publicly available gene trap cell lines in mouse
Gene trapping is a method of generating murine embryonic stem (ES) cell lines containing insertional mutations in known and novel genes. A number of international groups have used this approach to create sizeable public cell line repositories available to the scientific community for the generation of mutant mouse strains. The major gene trapping groups worldwide have recently joined together to centralize access to all publicly available gene trap lines by developing a user-oriented Website for the International Gene Trap Consortium (IGTC). This collaboration provides an impressive public informatics resource comprising ∼45 000 well-characterized ES cell lines which currently represent ∼40% of known mouse genes, all freely available for the creation of knockout mice on a non-collaborative basis. To standardize annotation and provide high confidence data for gene trap lines, a rigorous identification and annotation pipeline has been developed combining genomic localization and transcript alignment of gene trap sequence tags to identify trapped loci. This information is stored in a new bioinformatics database accessible through the IGTC Website interface. The IGTC Website () allows users to browse and search the database for trapped genes, BLAST sequences against gene trap sequence tags, and view trapped genes within biological pathways. In addition, IGTC data have been integrated into major genome browsers and bioinformatics sites to provide users with outside portals for viewing this data. The development of the IGTC Website marks a major advance by providing the research community with the data and tools necessary to effectively use public gene trap resources for the large-scale characterization of mammalian gene function
Discovery of the bright trans-Neptunian object 2000 EB173
We describe the discovery circumstances and photometric properties of 2000 EB173, now one of the brightest trans-Neptunian objects (TNOs) with opposition magnitude mR = 18.9 and also one of the largest Plutinos, found with the drift-scanning camera of the Quasar Equatorial Survey Team, attached to the 1 m Schmidt telescope of the National Observatory of Venezuela. We measure B-V = 0.99 ± 0.14 and V-R = 0.57 ± 0.05, a red color observed for many fainter TNOs. At our magnitude limit mK = 20.1 ± 0.20, our single detection reveals a sky density of 0.015+0.034-0.012 TNOs per square degree (the error bars are 68% confidence limits), consistent with fainter surveys showing a cumulative number proportional to 100.5mR. Assuming an inclination distribution of TNOs with FWHM exceeding 30°, it is likely that 100 to several hundred objects brighter than mR = 20.1 remain to be discovered
New Quasars Detected via Variability in the QUEST1 Survey
By observing the high galactic latitude equatorial sky in drift scan mode
with the QUEST (QUasar Equatorial Survey Team) Phase 1 camera, multi-bandpass
photometry on a large strip of sky, resolved over a large range of time scales
(from hourly to biennially) has been collected. A robust method of ensemble
photometry revealed those objects within the scan region that fluctuate in
brightness at a statistically significant level. Subsequent spectroscopic
observations of a subset of those varying objects easily discriminated the
quasars from stars. For a 13-month time scale, 38% of the previously known
quasars within the scan region were seen to vary in brightness and subsequent
spectroscopic observation revealed that approximately 7% of all variable
objects in the scan region are quasars. Increasing the time baseline to 26
months increased the percentage of previously known quasars which vary to 61%
and confirmed via spectroscopy that 7% of the variable objects in the region
are quasars. This reinforces previously published trends and encourages
additional and ongoing synoptic searches for new quasars and their subsequent
analysis. During two spectroscopic observing campaigns, a total of 30 quasars
were confirmed, 11 of which are new discoveries and 19 of which were determined
to be previously known. Using the previously cataloged quasars as a benchmark,
we have found it possible to better optimize future variability surveys. This
paper reports on the subset of variable objects which were spectroscopically
confirmed as quasars.Comment: 22 pages, 3 figures, 4 tables. ApJ, submitted revised version: 19
pages, 4 figures, 2 tables, added clarifications, fixed typos, accepted by
ApJ 24 Jan 200
A Large Area CCD Camera for the Schmidt Telescope at the Venezuelan National Astronomical Observatory
We have designed, constructed and put into operation a large area CCD camera
that covers a large fraction of the image plane of the 1 meter Schmidt
telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices
arranged in a 4 x 4 mosaic covering 2.3 degrees x 3.5 degrees of sky. The CCDs
are 2048 x 2048 LORAL devices with 15 micron pixels. The camera is optimized
for drift scan photometry and objective prism spectroscopy. The design
considerations, construction features and performance parameters are described
in the following article.Comment: 34 pages, 18 figures, accepted for publication in PAS
Tnni3k Modifies Disease Progression in Murine Models of Cardiomyopathy
The Calsequestrin (Csq) transgenic mouse model of cardiomyopathy exhibits wide variation in phenotypic progression dependent on genetic background. Seven heart failure modifier (Hrtfm) loci modify disease progression and outcome. Here we report Tnni3k (cardiac Troponin I-interacting kinase) as the gene underlying Hrtfm2. Strains with the more susceptible phenotype exhibit high transcript levels while less susceptible strains show dramatically reduced transcript levels. This decrease is caused by an intronic SNP in low-transcript strains that activates a cryptic splice site leading to a frameshifted transcript, followed by nonsense-mediated decay of message and an absence of detectable protein. A transgenic animal overexpressing human TNNI3K alone exhibits no cardiac phenotype. However, TNNI3K/Csq double transgenics display severely impaired systolic function and reduced survival, indicating that TNNI3K expression modifies disease progression. TNNI3K expression also accelerates disease progression in a pressure-overload model of heart failure. These combined data demonstrate that Tnni3k plays a critical role in the modulation of different forms of heart disease, and this protein may provide a novel target for therapeutic intervention
TNOs are Cool: A survey of the trans-Neptunian region V. Physical characterization of 18 Plutinos using Herschel PACS observations
We present Herschel PACS photometry of 18 Plutinos and determine sizes and
albedos for these objects using thermal modeling. We analyze our results for
correlations, draw conclusions on the Plutino size distribution, and compare to
earlier results. Flux densities are derived from PACS mini scan-maps using
specialized data reduction and photometry methods. In order to improve the
quality of our results, we combine our PACS data with existing Spitzer MIPS
data where possible, and refine existing absolute magnitudes for the targets.
The physical characterization of our sample is done using a thermal model.
Uncertainties of the physical parameters are derived using customized Monte
Carlo methods. The correlation analysis is performed using a bootstrap Spearman
rank analysis. We find the sizes of our Plutinos to range from 150 to 730 km
and geometric albedos to vary between 0.04 and 0.28. The average albedo of the
sample is 0.08 \pm 0.03, which is comparable to the mean albedo of Centaurs,
Jupiter Family comets and other Trans-Neptunian Objects. We were able to
calibrate the Plutino size scale for the first time and find the cumulative
Plutino size distribution to be best fit using a cumulative power law with q =
2 at sizes ranging from 120-400 km and q = 3 at larger sizes. We revise the
bulk density of 1999 TC36 and find a density of 0.64 (+0.15/-0.11) g cm-3. On
the basis of a modified Spearman rank analysis technique our Plutino sample
appears to be biased with respect to object size but unbiased with respect to
albedo. Furthermore, we find biases based on geometrical aspects and color in
our sample. There is qualitative evidence that icy Plutinos have higher albedos
than the average of the sample.Comment: 18 pages, 8 figures, 8 tables, accepted for publication in A&
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