Promoting Comprehension Strategies of Primary Grade Students Through Datacasting Materials for Distance Learning

Many online learners especially in resource-challenged schools struggled with learning gaps during the pandemic crisis. This study focuses on using cost effective datacasting learning materials for distance education that promote intermediate grade students’ self-regulation, reading and writing skills. Datacasting is the process of delivering computer (IP) data over a traditional television broadcast signal. Locally, where only some households have Internet access but many have television sets, datacasting affords greater learning opportunities. Guided by structure, interactivity, and the functional language teaching theory, this study used sequential explanatory design to explore the role of datacasting in a public elementary school in Cavite in the academic year 2021 to 2022. Analyses of students’ artifacts reveal that their levels ofautonomy are non-autonomous, semi-autonomous, and autonomous. Moreover, the data also show that when they navigated the materials, they used these types of comprehension strategies: preparational, organizational, elaboration, andmonitoring. Correlations between culminating writing activities and final writing scores were found, but are not statistically significant, which may be attributed to the pandemic-induced sample attrition. The results suggest a need to refine the learning materials following the multimedia principles of personalization and embodiment through judicious text choice and adaptation and task design. Pedagogical recommendations for the use of datacasting materials are also offered

El principismo argentino ante la Primera Guerra Mundial

Hasta la primera guerra mundial de 1914-1918, la humanidad no había presenciado un cataclismo bélico de tal magnitud. Resultó lógico que esa situación trastocara todas las normas del derecho internacional, las relaciones entre los pueblos y la convivencia política económica del mundo entero. La Argentina no estuvo al margen de tales acontecimientos y transformaciones y, aunque adoptara una posición neutralista que la apartó del contexto beligerante, no quedó fuera de la comunidad internacional y, esa misma posición, le otorgó singular prestancia para definir cuestiones principistas que han quedado como una lección pacifista, ansiosa de la justicia, la tolerancia y la hermandad entre los pueblos y los hombres. Para estudiar la situación argentina frente a la Gran Guerra necesitamos bucear en los antecedentes inmediatos al conflicto y en los intereses europeos que allí se pusieron de manifiesto

Implementation of a chemical background method for atmospheric OH measurements by laser-induced fluorescence: characterisation and observations from the UK and China

Hydroxyl (OH) and hydroperoxy (HO2) radicals are central to the understanding of atmospheric chemistry. Owing to their short lifetimes, these species are frequently used to test the accuracy of model predictions and their underlying chemical mechanisms. In forested environments, laser-induced fluorescence–fluorescence assay by gas expansion (LIF–FAGE) measurements of OH have often shown substantial disagreement with model predictions, suggesting the presence of unknown OH sources in such environments. However, it is also possible that the measurements have been affected by instrumental artefacts, due to the presence of interfering species that cannot be discriminated using the traditional method of obtaining background signals via modulation of the laser excitation wavelength (“OHwave”). The interference hypothesis can be tested by using an alternative method to determine the OH background signal, via the addition of a chemical scavenger prior to sampling of ambient air (“OHchem”). In this work, the Leeds FAGE instrument was modified to include such a system to facilitate measurements of OHchem, in which propane was used to selectively remove OH from ambient air using an inlet pre-injector (IPI). The IPI system was characterised in detail, and it was found that the system did not reduce the instrument sensitivity towards OH ( 99 %) without the removal of OH formed inside the fluorescence cell (< 5 %). Tests of the photolytic interference from ozone in the presence of water vapour revealed a small but potentially significant interference, equivalent to an OH concentration of ∼4×105 molec. cm−3 under typical atmospheric conditions of [O3] =50 ppbv and [H2O] =1 %. Laboratory experiments to investigate potential interferences from products of isoprene ozonolysis did result in interference signals, but these were negligible when extrapolated down to ambient ozone and isoprene levels. The interference from NO3 radicals was also tested but was found to be insignificant in our system. The Leeds IPI module was deployed during three separate field intensives that took place in summer at a coastal site in the UK and both in summer and winter in the megacity of Beijing, China, allowing for investigations of ambient OH interferences under a wide range of chemical and meteorological conditions. Comparisons of ambient OHchem measurements to the traditional OHwave method showed excellent agreement, with OHwave vs OHchem slopes of 1.05–1.16 and identical behaviour on a diel basis, consistent with laboratory interference tests. The difference between OHwave and OHchem (“OHint”) was found to scale non-linearly with OHchem, resulting in an upper limit interference of (5.0±1.4) ×106 molec. cm−3 at the very highest OHchem concentrations measured (23×106 molec. cm−3), accounting for ∼14 %–21 % of the total OHwave signal