1,240 research outputs found
Automatization and Retention of Literacy Skills in Adult Learners
Findings from recent efficacy studies comparing literacy program types suggest that struggling adult readers often make limited to moderate gains across varied types of literacy interventions, with no specific approach consistently surpassing others to date. An alternative to comparing program types is to investigate whether there are specific characteristics or skills that vary by individual that can predict higher gains and skill retention across program type. Using an experimental, prospective, longitudinal design, the present study examined the role of automatization (over-learning) of component skills involved in reading during participation in general literacy programs. On average, participants in the study gained the equivalent of one full reading grade-level after participation in programs for six months. The degree of automatization of reading skills was found to be the strongest predictor of gains made during programs; a measure of automatization was also the strongest predictor of subsequent retention of skills, months later at follow-up testing. Implications for adult literacy practitioners and directions for future research related to skill retention are discussed
First Results from the Large Area Lyman Alpha Survey
We report on a new survey for z=4.5 Lyman alpha sources, the Large Area Lyman
Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume
and sensitivity by using narrow-band filters on the new 8192x8192 pixel CCD
Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National
Observatory.
Well-detected sources with flux and equivalent width matching known high
redshift Lyman alpha galaxies (i.e., observed equivalent width above 80
Angstroms and line+continuum flux between 2.6e-17 and 5.2e-17 erg/cm^2/sec in
an 80 Angstrom filter) have an observed surface density corresponding to 11000
+- 700 per square degree per unit redshift at z=4.5. Spatial variation in this
surface density is apparent on comparison between counts in 6561 and 6730
Angstrom filters.
Early spectroscopic followup results from the Keck telescope included three
sources meeting our criteria for good Lyman alpha candidates. Of these, one is
confirmed as a z=4.52 source, while another remains consistent with either
z=4.55 or z=0.81. We infer that 30 to 50% of our good candidates are bona fide
Lyman alpha emitters, implying a net density of about 4000 Lyman alpha galaxies
per square degree per unit redshift.Comment: 10 pages, 2 figures (3 .ps files), uses AASTeX 4. Submitted to The
Astrophysical Journal Letter
SPITZER/IRAC-MIPS Survey of NGC2451A and B: Debris Disks at 50-80 million years
We present a Spitzer IRAC and MIPS survey of NGC 2451 A and B, two open
clusters in the 50-80 Myr age range. We complement these data with extensive
ground-based photometry and spectroscopy to identify the cluster members in the
Spitzer survey field. We find only two members with 8 micron excesses. The
incidence of excesses at 24 microns is much higher, 11 of 31 solar-like stars
and 1 of 7 early-type (A) stars. This work nearly completes the debris disk
surveys with Spitzer of clusters in the 30-130 Myr range. This range is of inte
rest because it is when large planetesimal collisions may have still been
relatively common (as indicated by the one that led to the formation of the
Moon during this period of the evolution of the Solar System). We review the
full set of surveys and find that there are only three possible cases out of
about 250 roughly solar-mass stars where very large excesses suggest that such
collisions have occurred recently.Comment: Accepted for publication in ApJ. 25 pages 17 figure
Recommended from our members
A Study of the Safety and Efficacy of Travoprost 0.004%/Timolol 0.5% Ophthalmic Solution Compared to Latanoprost 0.005% and Timolol 0.5% Dosed Concomitantly in Patients with Open-Angle Glaucoma or Ocular Hypertension
Background/Aims: To compare the intraocular pressure (IOP)-lowering efficacy of travoprost 0.004%/timolol 0.5% in fixed combination with the unfixed combination of latanoprost 0.005% and timolol 0.5% in open-angle glaucoma or ocular hypertension patients with IOP levels below 18 mmHg on the unfixed combination of latanoprost 0.005% and timolol 0.5%. Methods: Following a 30-day open-label run-in with latanoprost QD PM and timolol QD AM, subjects with intraocular pressure below 18 mmHg were randomized to continue concomitant latanoprost QD PM and timolol QD AM or switch to travoprost 0.004%/timolol 0.5% QD AM and vehicle QD PM in masked fashion and were followed for 3 months. The primary efficacy endpoint was mean IOP reduction from baseline. Results: There were no clinically relevant or statistically significant differences in mean IOP, mean IOP change from baseline, or percentage IOP change from baseline between the two treatment groups. Between-group differences in mean IOP were within ±0.3 mmHg at all time points (p ≥ 0.384), and between-group differences in mean IOP change from baseline were within ±0.4 mmHg at all time points. Overall, 88% of patients whose IOP was less than 18 mmHg on the unfixed combination of latanoprost and timolol remained well controlled on the same regimen in the masked portion of the study, compared with 92% who remained well controlled after switching to travoprost/timolol. Conclusion: Travoprost 0.004%/timolol 0.5% administered once daily and concomitant administration of timolol 0.5% and latanoprost 0.005% produce similar maintenance of IOP-lowering effect in patients who were previously well controlled on concomitant administration of latanoprost and timolol. Patients who are well controlled on latanoprost and timolol concomitant therapy can be switched to once-daily therapy with travoprost 0.004%/timolol 0.5% with no expected compromise in the safety and efficacy of their treatment
SIGL:Securing Software Installations Through Deep Graph Learning
Many users implicitly assume that software can only be exploited after it is
installed. However, recent supply-chain attacks demonstrate that application
integrity must be ensured during installation itself. We introduce SIGL, a new
tool for detecting malicious behavior during software installation. SIGL
collects traces of system call activity, building a data provenance graph that
it analyzes using a novel autoencoder architecture with a graph long short-term
memory network (graph LSTM) for the encoder and a standard multilayer
perceptron for the decoder. SIGL flags suspicious installations as well as the
specific installation-time processes that are likely to be malicious. Using a
test corpus of 625 malicious installers containing real-world malware, we
demonstrate that SIGL has a detection accuracy of 96%, outperforming similar
systems from industry and academia by up to 87% in precision and recall and 45%
in accuracy. We also demonstrate that SIGL can pinpoint the processes most
likely to have triggered malicious behavior, works on different audit platforms
and operating systems, and is robust to training data contamination and
adversarial attack. It can be used with application-specific models, even in
the presence of new software versions, as well as application-agnostic
meta-models that encompass a wide range of applications and installers.Comment: 18 pages, to appear in the 30th USENIX Security Symposium (USENIX
Security '21
Auntie knows best? public broadcasters and current affairs knowledge
Public service broadcasters (PSBs) are a central part of national news media landscapes. In many countries, PSBs are the first choice of citizens when it comes to news providers. And in perhaps more countries still, PSBs are thought of as specialists in provision of hard news. We test this proposition here using survey data from a large crossnational survey involving indicators of current affairs knowledge and media consumption. Specifically, we examine whether exposure to public versus commercial news influences the knowledge citizens possess about current affairs, both domestically and internationally. We
also test, using propensity score analysis, whether there is variation across PSBs in this regard. Results indicate that compared to commercial news, watching PSB has a net
positive influence on knowledge of hard news, though not all PSBs are equally effective in contributing to knowledge acquisition. This knowledge gap between PSB and commercial
news media consumption appears to be mitigated by factors such as de jure independence,proportion of public financing, and audience share
A study of the safety and efficacy of travoprost 0.004%/timolol 0.5% ophthalmic solution compared to latanoprost 0.005% and timolol 0.5% dosed concomitantly in patients with open-angle glaucoma or ocular hypertension
Douglas J Rhee1, James H Peace2, Sushanta Mallick3, Theresa A Landry3, Michael VW Bergamini3, and the Study Group*1Massachusetts Eye and Ear Infirmary, Harvard University, Boston, MA, USA; 2Diabetic Eye Medical Clinic, Inglewood, CA, USA; 3Alcon Laboratories, Inc., Ft. Worth, TX, USA; *Study Group members listed in AppendixBackground/Aims: To compare the intraocular pressure (IOP)-lowering efficacy of travoprost 0.004%/timolol 0.5% in fixed combination with the unfixed combination of latanoprost 0.005% and timolol 0.5% in open-angle glaucoma or ocular hypertension patients with IOP levels below 18 mmHg on the unfixed combination of latanoprost 0.005% and timolol 0.5%.Methods: Following a 30-day open-label run-in with latanoprost QD PM and timolol QD AM, subjects with intraocular pressure below 18 mmHg were randomized to continue concomitant latanoprost QD PM and timolol QD AM or switch to travoprost 0.004%/timolol 0.5% QD AM and vehicle QD PM in masked fashion and were followed for 3 months. The primary efficacy endpoint was mean IOP reduction from baseline.Results: There were no clinically relevant or statistically significant differences in mean IOP, mean IOP change from baseline, or percentage IOP change from baseline between the two treatment groups. Between-group differences in mean IOP were within ±0.3 mmHg at all time points (p ≥ 0.384), and between-group differences in mean IOP change from baseline were within ±0.4 mmHg at all time points. Overall, 88% of patients whose IOP was less than 18 mmHg on the unfixed combination of latanoprost and timolol remained well controlled on the same regimen in the masked portion of the study, compared with 92% who remained well controlled after switching to travoprost/timolol.Conclusion: Travoprost 0.004%/timolol 0.5% administered once daily and concomitant administration of timolol 0.5% and latanoprost 0.005% produce similar maintenance of IOP-lowering effect in patients who were previously well controlled on concomitant administration of latanoprost and timolol. Patients who are well controlled on latanoprost and timolol concomitant therapy can be switched to once-daily therapy with travoprost 0.004%/timolol 0.5% with no expected compromise in the safety and efficacy of their treatment.Keywords: travoprost, timolol, glaucoma, intraocular pressure, fixed combinatio
Is there Evidence for Flat Cores in the Halos of Dwarf Galaxies?: The Case of NGC 3109 and NGC 6822
Two well studied dwarf galaxies -- NGC 3109 and NGC 6822 -- present some of
the strongest observational support for a flat core at the center of galactic
dark matter (DM) halos. We use detailed cosmologically motivated numerical
models to investigate the systematics and the accuracy of recovering parameters
of the galaxies. Some of our models match the observed structure of the two
galaxies remarkably well. Our analysis shows that the rotation curves of these
two galaxies are instead quite compatible with their DM halos having steep
cuspy density profiles. The rotation curves in our models are measured using
standard observational techniques. The models reproduce the rotation curves of
both galaxies, the disk surface brightness profiles as well as the profile of
isophotal ellipticity and position angle. The models are centrally dominated by
baryons; however, the dark matter component is globally dominant. The simulated
disk mass is marginally consistent with a stellar mass-to-light ratio in
agreement with the observed colors. We show that non-circular motions combined
with gas pressure support and projection effects results in a large
underestimation of the circular velocity in the central kpc region,
creating the illusion of a constant density core. Although the systematic
effects mentioned above are stronger in barred systems, they are also present
in axisymetric disks. Our results strongly suggest that there is no
contradiction between the observed rotation curves in dwarf galaxies and the
cuspy central dark matter density profiles predicted by Cold Dark Matter
models.Comment: Accepted for publication in the ApJ. New discussion, figures and one
appendix. High resolution version
at:http://www.astro.washington.edu/octavio/N3109_paper.ps.g
Cold gas outflows from the Small Magellanic Cloud traced with ASKAP
Feedback from massive stars plays a critical role in the evolution of the
Universe by driving powerful outflows from galaxies that enrich the
intergalactic medium and regulate star formation. An important source of
outflows may be the most numerous galaxies in the Universe: dwarf galaxies.
With small gravitational potential wells, these galaxies easily lose their
star-forming material in the presence of intense stellar feedback. Here, we
show that the nearby dwarf galaxy, the Small Magellanic Cloud (SMC), has atomic
hydrogen outflows extending at least 2 kiloparsecs (kpc) from the star-forming
bar of the galaxy. The outflows are cold, , and may have formed
during a period of active star formation million years (Myr) ago. The
total mass of atomic gas in the outflow is solar masses, , or % of the total atomic gas of the galaxy. The inferred
mass flux in atomic gas alone, , is up to an order of magnitude greater than the star
formation rate. We suggest that most of the observed outflow will be stripped
from the SMC through its interaction with its companion, the Large Magellanic
Cloud (LMC), and the Milky Way, feeding the Magellanic Stream of hydrogen
encircling the Milky Way.Comment: Published in Nature Astronomy, 29 October 2018,
http://dx.doi.org/10.1038/s41550-018-0608-
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