1,351 research outputs found
Speling it rite eevn aftr the test : what students can tell us
This paper describes a teacher inservice designed to aid teachers in implementing a developmental spelling program in an elementary setting. Developmentally appropriate instruction in spelling takes into account a student\u27s existing knowledge of words. Such a program consists of understanding each student\u27s level of knowledge, selecting word lists to meet the students\u27 needs; providing explicit instruction about spelling patterns, and continually assessing students\u27 spelling progress through authentic, written work
The questions this project will address include: (a) Why should a developmental spelling program be implemented, (b) what research supports a developmental approach to spelling instruction, (c) what are the potential benefits for students, and (d) how can a developmental spelling program be implemented and evaluated in the classroom?
The inservice described in this paper includes three two-hour work sessions. The purpose of these inservice sessions is to introduce elementary teachers to developmental spelling theory, instruction, and assessment. The inservice will include experiences in assessing students\u27 developmental spelling stages, selecting words based on students\u27 abilities, and using a variety of student practice options in learning new words. Finally, teachers will reflect on the progress made by their own students as a developmental spelling approach is implemented and study groups continue collaborative learning after the inservice is completed
Newtonian and Post-Newtonian approximations of the k = 0 Friedmann Robertson Walker Cosmology
In a previous paper we derived a post-Newtonian approximation to cosmology
which, in contrast to former Newtonian and post-Newtonian cosmological
theories, has a well-posed initial value problem. In this paper, this new
post-Newtonian theory is compared with the fully general relativistic theory,
in the context of the k = 0 Friedmann Robertson Walker cosmologies. It is found
that the post-Newtonian theory reproduces the results of its general
relativistic counterpart, whilst the Newtonian theory does not.Comment: 11 pages, Latex, corrected typo
A novel approach to identify blazar emission states using clustering algorithms
Even after decades of multi-wavelength (MWL) observations, blazars still
remain mysterious objects. Their extreme variability and variety of emission
characteristics observed during different time periods make it hard to
understand the fundamental processes behind their emission. Thus, a robust
identification and characterization of the different emission states among
blazars is vital to investigate the underlying processes causing the observed
emission. In this contribution, we present a novel technique to determine
emission states across MWL lightcurves (LCs) of blazars using a clustering
algorithm. Using the Extreme Deconvolution algorithm, we apply a Gaussian
Mixture model to the 12-year long-term LC of one of our archetypal blazars, Mrk
501. The two main advantages of the method are that, compared to more
conventional methods, such as the Bayesian block algorithm, it considers
multiple wavebands simultaneously and it is not dependent on the order in time
of the data points. This allows to assign data points to the same emission
state even though they are separated by other states in time. The well sampled
gamma-ray, X-ray and radio LCs used as input allow to identify six clusters.
The clustering is mainly driven by the X-ray flux, showing different levels of
quiescent, intermediate and high flux states. However, the radio flux reveals a
more complicated pattern, dividing some of the X-ray flux levels in low and
high-radio flux states. This suggests that multiple emission regions maybe
responsible for the radio to gamma-ray flux.Comment: 8 pages, 1 figure, Presented at the 38th International Cosmic Ray
Conference (ICRC 2023), 202
Design of interactive visualization of models and students data
This document reports the design of the interactive visualizations of open student models that will
be performed in GRAPPLE. The visualizations will be based on data stored in the domain model and student model, and aim at supporting learners to be more engaged in the learning process, and instructors in assisting the learners
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Expression of target and reference genes in Daphnia magna exposed to ibuprofen
Background: Transcriptomic techniques are now being applied in ecotoxicology and toxicology to measure the impact of stressors and develop understanding of mechanisms of toxicity. Microarray technology in particular offers the potential to measure thousands of gene responses simultaneously. However, it is important that microarrays responses should be validated, at least initially, using real-time quantitative polymerase chain reaction (QPCR). The accurate measurement of target gene expression requires normalisation to an invariant internal control e. g., total RNA or reference genes. Reference genes are preferable, as they control for variation inherent in the cDNA synthesis and PCR. However, reference gene expression can vary between tissues and experimental conditions, which makes it crucial to validate them prior to application. Results: We evaluated 10 candidate reference genes for QPCR in Daphnia magna following a 24 h exposure to the non-steroidal anti-inflammatory drug (NSAID) ibuprofen (IB) at 0, 20, 40 and 80 mg IB l(-1). Six of the 10 candidates appeared suitable for use as reference genes. As a robust approach, we used a combination normalisation factor (NF), calculated using the geNorm application, based on the geometric mean of three selected reference genes: glyceraldehyde-3-phosphate dehydrogenase, ubiquitin conjugating enzyme and actin. The effects of normalisation are illustrated using as target gene leukotriene B4 12-hydroxydehydrogenase (Ltb4dh), which was upregulated following 24 h exposure to 63-81 mg IB l(-1). Conclusions: As anticipated, use of the NF clarified the response of Ltb4dh in daphnids exposed to sublethal levels of ibuprofen. Our findings emphasise the importance in toxicogenomics of finding and applying invariant internal QPCR control(s) relevant to the study conditions
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