1,240 research outputs found

    Automatization and Retention of Literacy Skills in Adult Learners

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    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

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    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

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    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

    SIGL:Securing Software Installations Through Deep Graph Learning

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    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

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    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

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    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

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    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 1\sim 1 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

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    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, T<400 KT<400~{\rm K}, and may have formed during a period of active star formation 256025 - 60 million years (Myr) ago. The total mass of atomic gas in the outflow is 107\sim 10^7 solar masses, M{\rm M_{\odot}}, or 3\sim 3% of the total atomic gas of the galaxy. The inferred mass flux in atomic gas alone, M˙HI0.21.0 M yr1\dot{M}_{HI}\sim 0.2 - 1.0~{\rm M_{\odot}~yr^{-1}}, 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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