125,383 research outputs found
The Kepler Catalog of Stellar Flares
A homogeneous search for stellar flares has been performed using every
available Kepler light curve. An iterative light curve de-trending approach was
used to filter out both astrophysical and systematic variability to detect
flares. The flare recovery completeness has also been computed throughout each
light curve using artificial flare injection tests, and the tools for this work
have been made publicly available. The final sample contains 851,168 candidate
flare events recovered above the 68% completeness threshold, which were
detected from 4041 stars, or 1.9% of the stars in the Kepler database. The
average flare energy detected is ~ erg. The net fraction of flare
stars increases with color, or decreasing stellar mass. For stars in this
sample with previously measured rotation periods, the total relative flare
luminosity is compared to the Rossby number. A tentative detection of flare
activity saturation for low-mass stars with rapid rotation below a Rossby
number of ~0.03 is found. A power law decay in flare activity with Rossby
number is found with a slope of -1, shallower than typical measurements for
X-ray activity decay with Rossby number.Comment: 15 pages, 8 figures, ApJ accepted. Code is available online:
http://github.com/jradavenport/appaloos
Understanding the entanglement entropy and spectra of 2D quantum systems through arrays of coupled 1D chains
We describe an algorithm for studying the entanglement entropy and spectrum
of 2D systems, as a coupled array of one dimensional chains in their
continuum limit. Using the algorithm to study the quantum Ising model in 2D,
(both in its disordered phase and near criticality) we confirm the existence of
an area law for the entanglement entropy and show that near criticality there
is an additive piece scaling as with .
\textcolor{black}{Studying the entanglement spectrum, we show that entanglement
gap scaling can be used to detect the critical point of the 2D model. When
short range (area law) entanglement dominates we find (numerically and
perturbatively) that this spectrum reflects the energy spectrum of a single
quantum Ising chain.Comment: 8 pages (4 + supplementary material). 10 figure
Assessing mobile mixed reality affordances as a comparative visualization pedagogy for design communication
Spatial visualisation skills and interpretation are critical in the design professions but are difficult for novice designers. There is growing evidence that mixed reality visualisation improves learner outcomes, but often these studies are focused on a single media representation and not on a comparison between media and the underpinning learning outcomes. Results from recent studies highlight the use of comparative visualisation pedagogy in design through learner reflective blogs and pilot studies with experts, but these studies are limited by expense and designs familiar to the learner. With increasing interest in mobile pedagogy, more assessment is required in understanding learner interpretation of comparative mobile mixed reality pedagogy. The aim of this study is to do this by evaluating insights from a first-year architectural design classroom through studying the impact and use of a range of mobile comparative visualisation technologies. Using a design-based research methodology and a usability framework for accessing comparative visualisation, this paper will study the complexities of spatial design in the built environment. Outcomes from the study highlight the positives of the approach but also the improvements required in the delivery of the visualisations to improve on the visibility and visual errors caused by the lack of mobile processing
Anatomy and Histology of the Male Reproductive Complex of the Onion Maggot Fly, \u3ci\u3eDelia Antiqua\u3c/i\u3e, (Diptera: Anthomyiidae) Including Some Comparisons With \u3ci\u3eD. Platura\u3c/i\u3e and \u3ci\u3eD. Radicum\u3c/i\u3e
In Delia antiqua (Meigen) (Diptera: Anthomyiidae), the male reproductive complex is composed of a pair of testes, paired vas deferens connecting the testes to the anterior ejaculatory duct, and a pair of paragonial (accessory) glands. Each D. antiqua paragonial gland consists of a single layer of secretory epithelial cells surrounded by a thin sheath of muscle tissue. The paragonial cells appear to be largely homogeneous in form, however a minor number of cells exhibit unique staining characteristics distinct from the main cells of the gland. This is preliminary evidence for a secondary cell type as has been found for Drosophila and Aedes paragonial glands. In contrast to the testis and vas deferens, where most of the growth occurs during the pupal stage, the D. antiqua paragonial glands expanded markedly due to secretory accumulation during the first days of adult life. Based on histochemical analyses, the paragonial secretion contained abundant protein, with evidence of glycoprotein. The reproductive complex in all three Delia species (D. antiqua, D. radicum (Bouche) and D. platura (Meigen)) appears similar, with the exception of size differences and timing of paragonial secretory accumulation and sperm maturation. Paragonial glands of D. radicum were the largest in both length and width, and only this species possessed abundant sperm upon eclosion. Of the three species, D. radicum appears most capable of mating immediately after eclosion based on the histology of its reproductive complex, which is consistent with biochemical and behavioral observations made earlier in this laboratory
Tracing the Dynamics of Disk Galaxies with Optical and IR Surface Photometry: Color Gradients in M99
We present optical and IR surface photometry of M99 (NGC 4254) at g, r_S i, J
and K'. We also present a K' image of M51 (NGC 5194) for comparison. Fourier
decomposition of the disk light reveals that the radial distribution of power
depends on wavelength, which in turn implies that the spiral structure traced
in the visual (i.e. young population I and dust) is different from the one
detected at 2 microns (i.e. old stellar disk). We observe radial modulation of
the power and a dependency of power with wavelength that are consistent with
modal theory of spiral structure.
A central motivation for our research is the fundamental idea of density wave
theory that the passage of a spiral density wave triggers star formation. We
have found a stellar population age gradient consistent with this scenario in a
reddening-free, red supergiant-sensitive, Q-like photometric parameter at 6 kpc
galactocentric distance across one of the arms of M99. We rule out that the
change in this parameter, Q(r_SJgi), across the arm is mainly due to dust. The
difference in Q(r_SJgi) going from the interarm regions to the arms also
indicates that arms cannot be due exclusively to crowding of stellar orbits.
We present the first measurement of Omega_p, the angular speed of the spiral
pattern, and of the location of the corotation radius, derived from the drift
velocity of the young stars away from their birth site. The measured Q(r_SJgi)
implies a star formation rate for M99 within the range of 10-20 M_odot/yr; a
disk stellar mass surface density of ~80 M_odot/pc^2; and a maximum
contribution of ~20 percent from red supergiants to the K' light in a small
region, and much smaller on average. We measure a K' arm--interarm contrast of
2-3, too high for M99 to be a truly isolated galaxy.Comment: 25 pages of uuencoded, compressed Postscript (text only). To appear
in 1 April 1996 issue of The Astrophysical Journal. Also available, together
with 2 uuencoded, compressed PostScript files with 10 figures each, at
http://astro.berkeley.edu/preprints.htm
Visualising mixed reality simulation for multiple users
Cowling, MA ORCiD: 0000-0003-1444-1563Blended reality seeks to encourage co-presence in the classroom, blending student experience across virtual and physical worlds. In a similar way, Mixed Reality, a continuum between virtual and real environments, is now allowing learners to work in both the physical and the digital world simultaneously, especially when combined with an immersive headset experience. This experience provides innovative new experiences for learning, but faces the challenge that most of these experiences are single user, leaving others outside the new environment. The question therefore becomes, how can a mixed reality simulation be experienced by multiple users, and how can we present that simulation effectively to users to create a true blended reality environment? This paper proposes a study that uses existing screen production research into the user and spectator to produce a mixed reality simulation suitable for multiple users. A research method using Design Based Research is also presented to assess the usability of the approach
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