919 research outputs found
Towards a responsible agenda for academic literacy development: considerations that will benefit students and society
The transition from secondary to higher education (HE) requires a change of cultural mindset (cf. Darlaston-Jones et al., 2003; Leki, 2006). It is widely accepted that the academic performance and motivation of first year students to stay in HE depend, among others, on how well they integrate into the university environment (Brinkworth et al., 2009). Academic integration or acculturation takes different forms. The premise of this article is that students have to learn to engage with academic discourse, i.e., they must acquire the community’s communicative currency, defined as different kinds of language used to reflect the community’s current norms, practices, values and expectations (cf., among others, Duff, 2010; Gee, 1998, 2000; Hyland, 2009). As reflective and responsible practitioners we therefore need to outline a critical agenda for academic acculturation by reviewing the debate on the nature of literacy and, particularly, by discussing similarities and differences in epistemology and approaches to literacy. Such an agenda will have to recognise insights gained from, in particular, the New Literacy Studies (Street, 1998, 2004) and the Academic Literacies movement (Lea & Street, 1998; Lillis & Scott, 2007), but it will also become enriched by a linguistic perspective (Biber, 2006; Blanton, 1994; Bachman & Palmer, 1996; Halliday, 1978, 1985, 1993, 1996, 2002; Hyland, 2009). In developing a template for the agenda we accordingly acknowledge the theoretical defensibility and the feasibility of different approaches to academic acculturation.Keywords: academic literacy development, academic discourse, academic acculturation or integration, higher educatio
Propensity-score based methods for causal inference in observational studies with non-binary treatments
Propensity score methods are a part of the standard toolkit for applied researchers who wish to ascertain causaleffects from observational data. While they were originally developed for binary treatments, several researchershave proposed generalizations of the propensity score methodology for non-binary treatment regimes. Suchextensions have widened the applicability of propensity score methods and are indeed becoming increasinglypopular themselves. In this article, we closely examine two methods that generalize propensity scores in thisdirection, namely, the propensity function (pf), and the generalized propensity score (gps), along with twoextensions of thegpsthat aim to improve its robustness. We compare the assumptions, theoretical properties,and empirical performance of these methods. On a theoretical level, thegpsand its extensions are advantageousin that they are designed to estimate the full dose response function rather than the average treatment effectthat is estimated with thepf. We comparegpswith a newpfmethod, both of which estimate the doseresponse function. We illustrate our findings and proposals through simulation studies, including one based onan empirical study about the effect of smoking on healthcare costs. While our proposedpf-based estimatorpreforms well, we generally advise caution in that all available methods can be biased by model misspecificationand extrapolation
Surveying the Agents of Galaxy Evolution in the Tidally Stripped, Low Metallicity Small Magellanic Cloud (SAGE-SMC). I. Overview
The Small Magellanic Cloud (SMC) provides a unique laboratory for the study of the lifecycle of dust given its low metallicity (~1/5 solar) and relative proximity (~60 kpc). This motivated the SAGE-SMC (Surveying the Agents of Galaxy Evolution in the Tidally Stripped, Low Metallicity Small Magellanic Cloud) Spitzer Legacy program with the specific goals of studying the amount and type of dust in the present interstellar medium, the sources of dust in the winds of evolved stars, and how much dust is consumed in star formation. This program mapped the full SMC (30 deg^2) including the body, wing, and tail in seven bands from 3.6 to 160 μm using IRAC and MIPS on the Spitzer Space Telescope. The data were reduced and mosaicked, and the point sources were measured using customized routines specific for large surveys. We have made the resulting mosaics and point-source catalogs available to the community. The infrared colors of the SMC are compared to those of other nearby galaxies and the 8 μm/24 μm ratio is somewhat lower than the average and the 70 μm/160 μm ratio is somewhat higher than the average. The global infrared spectral energy distribution (SED) shows that the SMC has approximately 1/3 the aromatic emission/polycyclic aromatic hydrocarbon abundance of most nearby galaxies. Infrared color-magnitude diagrams are given illustrating the distribution of different asymptotic giant branch stars and the locations of young stellar objects. Finally, the average SED of H II/star formation regions is compared to the equivalent Large Magellanic Cloud average H II/star formation region SED. These preliminary results will be expanded in detail in subsequent papers
Detection Of DNA Damage By Use Of Escherichia Coli Carrying recA\u27::lux, uvrA\u27::lux, And alkA\u27::lux Reporter Plasmids
Plasmids were constructed in which DNA damage-inducible promoters recA, uvrA, and alkA from Escherichia coli were fused to the Vibrio fischeri luxCDABE operon. Introduction of these plasmids into E. coli allowed the detection of a dose-dependent response to DNA-damaging agents, such as mitomycin and UV irradiation. Bioluminescence was measured in real time over extended periods. The fusion of the recA promoter to luxCDABE showed the most dramatic and sensitive responses. lexA dependence of the bioluminescent SOS response was demonstrated, confirming that this biosensor\u27s reports were transmitted by the expected regulatory circuitry. Comparisons were made between luxCDABE and lacZ fusions to each promoter. It is suggested that the lux biosensors may have use in monitoring chemical, physical, and genotoxic agents as well as in further characterizing the mechanisms of DNA repair
Oxidative Stress Detection With Escherichia Coli Harboring A katG\u27::lux Fusion
A plasmid containing a transcriptional fusion of the Escherichia coli katG promoter to a truncated Vibrio fischeri lux operon (luxCDABE) was constructed. An E. coli strain bearing this plasmid (strain DPD2511) exhibited low basal levels of luminescence, which increased up to 1,000-fold in the presence of hydrogen peroxide, organic peroxides, redox-cycling agents (methyl viologen and menadione), a hydrogen peroxide-producing enzyme system (xanthine and xanthine oxidase), and cigarette smoke. An oxyR deletion abolished hydrogen peroxide-dependent induction, confirming that oxyR controlled katG\u27::lux luminescence. Light emission was also induced by ethanol by an unexplained mechanism. A marked synergistic response was observed when cells were exposed to both ethanol and hydrogen peroxide; the level of luminescence measured in the presence of both inducers was much higher than the sum of the level of luminescence observed with ethanol and the level of luminescence observed with hydrogen peroxide. It is suggested that this construction or similar constructions may be used as a tool for assaying oxidant and antioxidant properties of chemicals, as a biosensor for environmental monitoring and as a tool for studying cellular responses to oxidative hazards
Reading Ability and Academic Acculturation: The Case of South African Students entering Higher Education
First-year students experience a range of challenges when transferring from secondary to higher education (HE) (cf. Darlaston-Jones et al. 2003, Leki 2006, Brinkworth et al. 2009). This is no different in South Africa, where deviating levels of preparedness for the demands of HE is a recurring theme (Slonimsky and Shalem 2005, Van Schalkwyk 2008, Scott 2009, Yeld 2009, Van Dyk 2010, Van Dyk and Coetzee-Van Rooy 2012). Weideman (2003:56) rightfully points out that the inability to understand and utilise appropriate academic discourse has a detrimental effect on academic success. Young students need to acculturate to the academic environment while adopting the academic community’s currency (Van de Poel and Gasiorek 2012a:294). With this article, we wish to contribute to the discussion by reporting on the academic language ability of one group of first-year students at a South African university, with specific reference to these students’ reading ability, on the basis of the following data: (i) individual differences in terms of learner characteristics (race, first language, gender, Grade 12 results, academic performance); (ii) self-reported reading preparedness; and (iii) reading profiles resulting from a valid and reliable academic literacy test, the Test of Academic Literacy Levels (TALL) and its Afrikaans counterpart, the Toets van Akademiese Geletterdheidsvlakke (TAG). The findings suggest that academic reading ability, as reflected in the test results, is indeed one of the salient contributors to academic success (as confirmed in the literature), regardless of social and individual differences, and that it needs to be supported in order for students to perceive their reading ability in accordance with their reading performance and be able to progress in their academic acculturation. A follow-up study will report on students’ awareness-raising about their own academic reading through the use of the validated scale for Perceived Academic Reading Preparedness (PARP) as a pedagogical tool.Keywords: Academic Acculturation, Academic Literacy, Academic Reading, Perceptions of Reading Ability, Academic Performanc
Revisiting at Large Dipion Masses
We revisit QCD factorization of form factors at large dipion
masses, by deriving new constraints based on the analyticity properties of
these objects. We then propose a parametrization of the form factors, inspired
by the leading-twist QCD factorization formula, that incorporates all known
analytic properties. This parameterization is used to interpolate between the
QCDF results and the constraints from the pole. Based on this
interpolation, we predict the decay rate in a larger phase
space region than previous studies could. We obtain a partially-integrated
branching ratio up to , which
implies that a measurement of the non-resonant semileptonic decay is
potentially within reach of the Belle II experiment.Comment: 15 pages, 1 figure, 2 table
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