427 research outputs found
The Sugar\u27d Game before Thee : Gamification Revisited
Gamification, the application of game elements to nongame contexts, was recently a subject of great interest in the library literature, inspiring a number of articles. That interest tapered off in tandem with gamification’s wider decline, but signs point to its reemergence. Anticipating renewed interest in gamification, the authors reviewed the literature to determine what has—and has not—been examined by librarianship’s proponents of gamification. They found serious concerns regarding gamification’s practical and ethical limitations. Moreover, the authors believe that the purported benefits of gamification are more readily found in its progenitor—games
The FIRST-2MASS Red Quasar Survey
Combining radio observations with optical and infrared color selection --
demonstrated in our pilot study to be an efficient selection algorithm for
finding red quasars -- we have obtained optical and infrared spectroscopy for
120 objects in a complete sample of 156 candidates from a sky area of 2716
square degrees. Consistent with our initial results, we find our selection
criteria -- J-K>1.7, R-K>4.0 -- yield a ~50% success rate for discovering
quasars substantially redder than those found in optical surveys. Comparison
with UVX- and optical color-selected samples shows that >~ 10% of the quasars
are missed in a magnitude-limited survey. Simultaneous two-frequency radio
observations for part of the sample indicate that a synchrotron continuum
component is ruled out as a significant contributor to reddening the quasars'
spectra. We go on to estimate extinctions for our objects assuming their red
colors are caused by dust. Continuum fits and Balmer decrements suggest E(B-V)
values ranging from near zero to 2.5 magnitudes. Correcting the K-band
magnitudes for these extinctions, we find that for K <= 14.0, red quasars make
up between 25% and 60% of the underlying quasar population; owing to the
incompleteness of the 2MASS survey at fainter K-band magnitudes, we can only
set a lower limit to the radio-detected red quasar population of >20-30%.Comment: 80 pages (single-column, preprint format) 20 figures, Accepted for
publicated in Ap
Imaging and spectroscopy of galaxies associated with two z~0.7 damped Lyman-alpha absorption systems
We have identified galaxies near two quasars which are at the redshift of
damped Lyman-alpha (DLA) systems in the UV spectra of the quasars. Both
galaxies are actively forming stars. One galaxy has a luminosity close to the
break in the local galaxy luminosity function, L*, the other is significantly
fainter than L* and appears to be interacting with a nearby companion. Despite
the strong selection effects favoring spectroscopic identification of the most
luminous DLA galaxies, many of the spectroscopically-identified DLA galaxies in
the literature are sub-L*, suggesting that the majority of the DLA population
is probably sub-L*, in contrast to MgII absorbers at similar redshifts whose
mean luminosity is close to L*.Comment: 9 pages, to appear in AJ, November 2003 issu
The Reddest Quasars
In a survey of quasar candidates selected by matching the FIRST and 2MASS
catalogs, we have found two extraordinarily red quasars. FIRST J013435.7-093102
is a 1 Jy source at z=2.216 and has B-K > 10, while FIRST J073820.1+275045 is a
2.5 mJy source at z=1.985 with B-K = 8.4. FIRST J073820.1+275045 has strong
absorption lines of MgII and CIV in the rest frame of the quasar and is highly
polarized in the rest frame ultraviolet, strongly favoring the interpretation
that its red spectral energy distribution is caused by dust reddening local to
the quasar. FIRST J073820.1+275045 is thus one of the few low radio-luminosity,
highly dust-reddened quasars known. The available observational evidence for
FIRST J013435.7-093102 leads us to conclude that it too is reddened by dust. We
show that FIRST J013435.7-093102 is gravitationally lensed, increasing the
number of known lensed, extremely dust-reddened quasars to at least three,
including MG0414-0534 and PKS1830-211. We discuss the implications of whether
these objects are reddened by dust in the host or lensing galaxies. If reddened
by their local environment, then we estimate that between 10 and 20% of the
radio-loud quasar population is reddened by dust in the host galaxy. The
discovery of FIRST J073820.1+275045 and objects now emerging from X-ray surveys
suggests the existence of an analogous radio-quiet red quasar population. Such
objects will be entirely missed by standard radio or optical quasar surveys. If
dust in the lensing galaxies is primarily responsible for the extreme redness
of the lensed quasars, then an untold number of gravitationally lensed quasars
are being overlooked.Comment: AASTEX 24 pp., 7 figs; accepted by ApJ. See also the preprint
astro-ph/0107435 by Winn et al., who independently discovered that
J013435.7-093102 is gravitationally lense
Imaging and Spectroscopy of Galaxies Associated with Two z ~ 0.7 Damped Lyα Absorption Systems
We have identified galaxies near two quasars that are at the redshift of damped Lyα (DLA) systems in the UV spectra of the quasars. Both galaxies are actively forming stars. One galaxy has a luminosity close to the break in the local galaxy luminosity function, L*; the other is significantly fainter than L* and appears to be interacting with a nearby companion. Despite the strong selection effects favoring spectroscopic identification of the most luminous DLA galaxies, many of the spectroscopically identified DLA galaxies in the literature are sub-L*, suggesting that the majority of the DLA population is probably sub-L*, in contrast to Mg II absorbers at similar redshifts, whose mean luminosity is close to L*
Social Genomics of Healthy and Disordered Internet Gaming
Objectives: To combine social genomics with cultural approaches to expand understandings of the somatic health dynamics of online gaming, including in the controversial nosological construct of internet gaming disorder (IGD).
Methods: In blood samples from 56 U.S. gamers, we examined expression of the conserved transcriptional response to adversity (CTRA), a leukocyte gene expression profile activated by chronic stress. We compared positively engaged and problem gamers, as identified by an ethnographically developed measure, the Positive and Negative Gaming Experiences Scale (PNGE-42), and also by a clinically derived IGD scale (IGDS-SF9).
Results: CTRA profiles showed a clear relationship with PNGE-42, with a substantial linkage to offline social support, but were not meaningfully associated with disordered play as measured by IGDS-SF9.
Conclusions: Our study advances understanding of the psychobiology of play, demonstrating via novel transcriptomic methods the association of negatively experienced internet play with biological measures of chronic threat, uncertainty, and distress. Our findings are consistent with the view that problematic patterns of online gaming are a proxy for broader patterns of biopsychosocial stress and distress such as loneliness, rather than a psychiatric disorder sui generis, which might exist apart from gamers ’ other life problems. By confirming the biological correlates of certain patterns of internet gaming, culturally-sensitive genomics approaches such as this can inform both evolutionary theorizing regarding the nature of play, as well as current psychiatric debates about the appropriateness of modeling distressful gaming on substance addiction and problem gambling
Live-Cell Monitoring of Periodic Gene Expression in Synchronous Human Cells Identifies Forkhead Genes involved in Cell Cycle Control
We developed a system to monitor periodic luciferase activity from cell cycle-regulated promoters in synchronous cells. Reporters were driven by a minimal human E2F1 promoter with peak expression in G1/S or a basal promoter with six Forkhead DNA-binding sites with peak expression at G2/M. After cell cycle synchronization, luciferase activity was measured in live cells at 10-min intervals across three to four synchronous cell cycles, allowing unprecedented resolution of cell cycle-regulated gene expression. We used this assay to screen Forkhead transcription factors for control of periodic gene expression. We confirmed a role for FOXM1 and identified two novel cell cycle regulators, FOXJ3 and FOXK1. Knockdown of FOXJ3 and FOXK1 eliminated cell cycle-dependent oscillations and resulted in decreased cell proliferation rates. Analysis of genes regulated by FOXJ3 and FOXK1 showed that FOXJ3 may regulate a network of zinc finger proteins and that FOXK1 binds to the promoter and regulates DHFR, TYMS, GSDMD, and the E2F binding partner TFDP1. Chromatin immunoprecipitation followed by high-throughput sequencing analysis identified 4329 genomic loci bound by FOXK1, 83% of which contained a FOXK1-binding motif. We verified that a subset of these loci are activated by wild-type FOXK1 but not by a FOXK1 (H355A) DNA-binding mutant
Using a complete spectroscopic survey to find red quasars and test the KX method
We present an investigation of quasar colour-redshift parameter space in
order to search for radio-quiet red quasars and to test the ability of a
variant of the KX quasar selection method to detect quasars over a full range
of colour without bias. This is achieved by combining IRIS2 imaging with the
complete Fornax Cluster Spectroscopic Survey to probe parameter space
unavailable to other surveys. We construct a new sample of 69 quasars with
measured bJ - K colours. We show that the colour distribution of these quasars
is significantly different from that of the Large Bright Quasar Survey's
quasars at a 99.9% confidence level. We find 11 of our sample of 69 quasars
have signifcantly red colours (bJ - K >= 3.5) and from this, we estimate the
red quasar fraction of the K <= 18.4 quasar population to be 31%, and robustly
constrain it to be at least 22%. We show that the KX method variant used here
is more effective than the UVX selection method, and has less colour bias than
optical colour-colour selection methods.Comment: 11 pages, 14 figures, accepted for publication in MNRA
Chandra Observations of 12 Luminous Red Quasars
We present results of a study of 12 dust-reddened quasars with 0.4 < z < 2.65
and reddenings in the range 0.15 < E(B-V) < 1.7. We obtained ACIS-S X-ray
spectra of these quasars, estimated the column densities towards them, and
hence obtained the gas:dust ratios in the material obscuring the quasar. We
detect all but one of the red quasars in the X-rays. Even though there is no
obvious correlation between the X-ray determined column densities of our
sources and their optical color or reddening, all of the sources show absorbed
X-ray spectra. When we correct the luminosity for absorption, they can be
placed among luminous quasars; therefore our objects belong to the group of
high luminosity analogues of the sources contributing to the X-ray background
seen in deep X-ray observations. Such sources are also found in serendipitous
shallow X-ray surveys. There is a hint that the mean spectral slope of the red
quasar is higher than that of normal, unobscured quasars, which could be an
indication for higher accretion rates and/or an evolutionary effect. We
investigate the number density of these sources compared to type 2 AGN based on
the X-ray background and estimate how many moderate luminosity red quasars may
be found in deep X-ray fields.Comment: Accepted for publication in ApJ. 21 pages, 3 figure
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