2,612 research outputs found
Cepheids and Long Period Variables in M33
We are conducting a long-term photometric survey of the nearby galaxy M33 to
discover Cepheids, eclipsing binaries, and long-period variables. The dataset
combines previously-obtained optical images from the DIRECT project with new
observations acquired at the WIYN 3.5m telescope. The entire data set spans
over 7 years with excellent synoptic coverage which will enable the discovery
and characterization of stars displaying variability over a wide range of
timescales (days, weeks, months, years). In this preliminary work we show
representative light curves of different variables we found so far in two
fields, color-magnitude diagrams, and optical Cepheid Period-Luminosity
relations for M33. The ultimate goal of the project is to provide an absolute
calibration of the Cepheid Period-Luminosity relation, and to study its
metallicity dependence at optical wavelengths.Comment: 3 pages, 6 figures. To appear in "Stellar Pulsation: Challenges for
Theory and Observation", Eds. J. Guzik and P. Bradle
A new version of the HBSC Family Affluence Scale - FAS III: Scottish qualitative findings from the International FAS Development Study
A critical review of the Family Affluence Scale (FAS) concluded that FAS II was no longer discriminatory within very rich or very poor countries, where a very high or a very low proportion of children were categorised as high FAS or low FAS respectively (Currie et al. 2008). The review concluded that a new version of FAS - FAS III - should be developed to take into account current trends in family consumption patterns across the European region, the US and Canada. In 2012, the FAS Development and Validation Study was conducted in eight countries - Denmark, Greenland, Italy, Norway, Poland, Romania, Slovakia and Scotland. This paper describes the Scottish qualitative findings from this study. The Scottish qualitative fieldwork comprising cognitive interviews and focus groups sampled from 11, 13 and 15 year-old participants from 18 of the most- and least- economically deprived schools. These qualitative results were used to inform the final FAS III recommendations.Publisher PDFPeer reviewe
Quantitative trait loci for bone traits segregating independently of those for growth in an F-2 broiler X layer cross
An F broiler-layer cross was phenotyped for 18 skeletal traits at 6, 7 and 9 weeks of age and genotyped with 120 microsatellite markers. Interval mapping identified 61 suggestive and significant QTL on 16 of the 25 linkage groups for 16 traits. Thirty-six additional QTL were identified when the assumption that QTL were fixed in the grandparent lines was relaxed. QTL with large effects on the lengths of the tarsometatarsus, tibia and femur, and the weights of the tibia and femur were identified on GGA4 between 217 and 249 cM. Six QTL for skeletal traits were identified that did not co-locate with genome wide significant QTL for body weight and two body weight QTL did not coincide with skeletal trait QTL. Significant evidence of imprinting was found in ten of the QTL and QTL x sex interactions were identified for 22 traits. Six alleles from the broiler line for weight- and size-related skeletal QTL were positive. Negative alleles for bone quality traits such as tibial dyschondroplasia, leg bowing and tibia twisting generally originated from the layer line suggesting that the allele inherited from the broiler is more protective than the allele originating from the layer
Size and shape constancy in consumer virtual reality
With the increase in popularity of consumer virtual reality headsets, for research and other applications, it is important to understand the accuracy of 3D perception in VR. We investigated the perceptual accuracy of near-field virtual distances using a size and shape constancy task, in two commercially available devices. Participants wore either the HTC Vive or the Oculus Rift and adjusted the size of a virtual stimulus to match the geometric qualities (size and depth) of a physical stimulus they were able to refer to haptically. The judgments participants made allowed for an indirect measure of their perception of the egocentric, virtual distance to the stimuli. The data show under-constancy and are consistent with research from carefully calibrated psychophysical techniques. There was no difference in the degree of constancy found in the two headsets. We conclude that consumer virtual reality headsets provide a sufficiently high degree of accuracy in distance perception, to allow them to be used confidently in future experimental vision science, and other research applications in psychology
Repartnering: the relevance of parenthood and gender to cohabitation and remarriage among the formerly married
This paper is an exploratory analysis of the impact of current and anticipated parenthood on cohabitation and remarriage among those formerly living in marriage-type relationships. The focus on children is embedded within a broader analysis of repartnering which takes account of other factors, including gender. Quantitative and qualitative analyses are used, with a multivariate analysis of repartnering patterns, using data from the General Household Survey, being complementedby in-depth interview data examining the attitudes of the formerly married to future relationships. The paper demonstrates that parenthood has a statistically significant effect on the likelihood of formerly married women repartnering, with a higher number of children being associated with a lower probability of repartnering. The presence of children can work against repartnering in a variety of ways. Children place demands on their parents and can deter or object to potential partners. Parents may see their parental role as more important than, and a barrier to, new relationships. However, mothers are typically looking for partners for themselves rather than fathers for their children. Among formerly married people without children, the desire to become a parent encourages repartnering. The paper concludes that parenthood should be a key consideration in analyses of repartnering
Space Qualification of the Optical Filter Assemblies for the ICESat-2/ATLAS Instrument
The Advanced Topographic Laser Altimeter System (ATLAS) will be the only instrument on the Ice, Cloud, and Land Elevation Satellite -2 (ICESat-2). ICESat-2 is the 2nd-generation of the orbiting laser altimeter ICESat, which will continue polar ice topography measurements with improved precision laser-ranging techniques. In contrast to the original ICESat design, ICESat-2 will use a micro-pulse, multi-beam approach that provides dense cross-track sampling to help scientists determine a surface's slope with each pass of the satellite. The ATLAS laser will emit visible, green laser pulses at a wavelength of 532 nm and a rate of 10 kHz and will be split into 6 beams. A set of six identical, thermally tuned optical filter assemblies (OFA) will be used to remove background solar radiation from the collected signal while transmitting the laser light to the detectors. A seventh assembly will be used to monitor the laser center wavelength during the mission. In this paper, we present the design and optical performance measurements of the ATLAS OFA in air and in vacuum prior to their integration on the ATLAS instrument
Study of the plutino object (208996) 2003 AZ84 from stellar occultations: size, shape and topographic features
We present results derived from four stellar occultations by the plutino
object (208996) 2003~AZ, detected at January 8, 2011 (single-chord
event), February 3, 2012 (multi-chord), December 2, 2013 (single-chord) and
November 15, 2014 (multi-chord). Our observations rule out an oblate spheroid
solution for 2003~AZ's shape. Instead, assuming hydrostatic equilibrium,
we find that a Jacobi triaxial solution with semi axes ~km % axis ratios and
, can better account for all our occultation observations.
Combining these dimensions with the rotation period of the body (6.75~h) and
the amplitude of its rotation light curve, we derive a density ~g~cm a geometric albedo . A grazing chord
observed during the 2014 occultation reveals a topographic feature along
2003~AZ's limb, that can be interpreted as an abrupt chasm of width
~km and depth ~km or a smooth depression of width ~km
and depth ~km (or an intermediate feature between those two extremes)
- …
