195 research outputs found

    The effect of ICT on schools’ efficiency: Empirical evidence on 23 European countries

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    In the last two decades, ICT use in schools grew exponentially. In this paper, the relationship between ICT and school’s efficiency and the mechanisms through which ICT can enhance schools’ productivity are investigated, using PISA 2018 data for about 5400 schools. Empirically, we analyze school’s efficiency in producing ICT-mediated instructional time as well as final educational output, by implementing a network Data Envelopment Analysis (DEA) model. The analysis is complemented by a conditional DEA to account for the presence of possible external drivers of schools’ efficiency. Results show that the average schools’ efficiency in using ICT is relatively low, and that it is mainly driven by the ability of translating ICT-mediated instructional time into learning, rather than by the amount of ICT and human resources. This evidence is consistent across countries. By investigating the role of ICT in schools’ efficiency the paper provides insights to guide the transition of digital technology into learning

    Estudio de la producciΓ³n de Γ‘cido linoleico conjugado por cepas de lactobacillus y enterococcus de distintos orΓ­genes

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    Conjugated linoleic acid (CLA) is a mixture of isomers of linoleic acid with conjugated double bonds. Several studies related the isoforms of CLA with beneficial effects such as anticarcenogenic activity, antiatherogenic activity, the ability to reduce body fat or to improve immune system function. Ruminal bacteria are the main responsible for CLA production. However other bacteria are also able to produce CLA from linoleic acid, such as Bifidobacterium, Enterococcus and Lactobacillus sp. The aim of this research was to evaluate the ability of several strains of Lactobacillus and Enterococcus isolated from different sources to produce CLA in order to use them for the production of functional foods. The results showed that the cis-9,trans-11 CLA isomer was the dominant one in all the strains studied. Lactobacillus gasseri LM21 was the main producer when incubated in anaerobiosis for 48 hours

    The Costs, Quality, and Scalability of Blended Learning in Postgraduate Management Education

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    With its combination of online and face-to-face interaction, blended learning is increasingly being employed in postgraduate education. To date, most empirical research on the topic has focused on the design and relative effectiveness of online versus in-person learning. Meanwhile, any exploration of the costs of its delivery has often been neglected. In this study, we propose a framework to assess the costs and cost-effectiveness of alternative designs of blended postgraduate programs, and then empirically apply it to an innovative blended Master of Business Administration (MBA) course as compared with similar MBAs taught at the same institution, with the differences lying in their proportions of online content and the intensity of their use. We applied the Community of Inquiry framework to show that the program with the most intensive use of online learning is also the most effective in terms of student cognitive gain. However, it is not the most cost-effective when compared to other, less online-intensive alternatives. We also found that this result depends on the scalability constraints imposed by the design of the programs. The implications of the scalability versus the quality versus the costs of blended education are then discussed

    Stable isotope evidence for dietary diversification in the pre-Columbian Amazon

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    Archaeological research is radically transforming the view that the Amazon basin and surrounding areas witnessed limited societal development before European contact. Nevertheless, uncertainty remains on the nature of the subsistence systems and the role that aquatic resources, terrestrial mammalian game, and plants had in supporting population growth, geographic dispersal, cultural adaptations and political complexity during the later stages of the pre-Columbian era. This is exacerbated by the general paucity of archaeological human remains enabling individual dietary reconstructions. Here we use stable carbon and nitrogen isotope analysis of bone collagen to reconstruct the diets of human individuals from SΓ£o LuΓ­s Island (Brazilian Amazon coast) dated between ca. 1800 and 1000Β cal BP and associated with distinct ceramic traditions. We expanded our analysis to include previously published data from MaracΓ‘ and MarajΓ³ Island, in the eastern Amazon. Quantitative estimates of the caloric contributions from food groups and their relative nutrients using a Bayesian Mixing Model revealed distinct subsistence strategies, consisting predominantly of plants and terrestrial mammals and variably complemented with aquatic resources. This study offers novel quantitative information on the extent distinct food categories of polyculture agroforestry systems fulfilled the caloric and protein requirements of Late Holocene pre-Columbian populations in the Amazon basin.Introduction Results - Stable isotope analysis and Bayesian dietary reconstruction Discussion Methods - Geographic and archaeological contexts - Sample preparation for stable isotopic analysis - Statistical analysis and Bayesian stable isotope mixing model

    E-Cadherin Acts as a Regulator of Transcripts Associated with a Wide Range of Cellular Processes in Mouse Embryonic Stem Cells

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    We have recently shown that expression of the cell adhesion molecule E-cadherin is required for LIF-dependent pluripotency of mouse embryonic stem (ES) cells.In this study, we have assessed global transcript expression in E-cadherin null (Ecad-/-) ES cells cultured in either the presence or absence of LIF and compared these to the parental cell line wtD3.We show that LIF has little effect on the transcript profile of Ecad-/- ES cells, with statistically significant transcript alterations observed only for Sp8 and Stat3. Comparison of Ecad-/- and wtD3 ES cells cultured in LIF demonstrated significant alterations in the transcript profile, with effects not only confined to cell adhesion and motility but also affecting, for example, primary metabolic processes, catabolism and genes associated with apoptosis. Ecad-/- ES cells share similar, although not identical, gene expression profiles to epiblast-derived pluripotent stem cells, suggesting that E-cadherin expression may inhibit inner cell mass to epiblast transition. We further show that Ecad-/- ES cells maintain a functional Ξ²-catenin pool that is able to induce Ξ²-catenin/TCF-mediated transactivation but, contrary to previous findings, do not display endogenous Ξ²-catenin/TCF-mediated transactivation. We conclude that loss of E-cadherin in mouse ES cells leads to significant transcript alterations independently of Ξ²-catenin/TCF transactivation

    VE-statin/egfl7 Expression in Endothelial Cells Is Regulated by a Distal Enhancer and a Proximal Promoter under the Direct Control of Erg and GATA-2

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    Angiogenesis is the process by which new blood vessels arise from existing ones by the budding out of endothelial cell capillaries from the luminal side of blood vessels. Blood vessel formation is essential for organ development during embryogenesis and is associated with several physiological and pathological processes, such as wound healing and tumor development. The VE-statin/egfl7 gene is specifically expressed in endothelial cells during embryonic development and in the adult. We studied here the regulatory mechanisms that control this tissue-specific expression. RT-qPCR analyses showed that the specificity of expression of VE-statin/egfl7 in endothelial cells is not shared with its closest neighbor genes notch1 and agpat2 on the mouse chromosome 2. Chromatin-immunoprecipitation analysis of histone modifications at the VE-statin/egfl7 locus showed that the chromatin is specifically opened in endothelial cells, but not in fibroblasts at the transcription start sites. A 13 kb genomic fragment of promoter was cloned and analyzed by gene reporter assays which showed that two conserved regions are important for the specific expression of VE-statin/egfl7 in endothelial cells; a βˆ’8409/βˆ’7563 enhancer and the βˆ’252/+38 region encompassing the exon-1b transcription start site. The latter contains essential GATA and ETS-binding sites, as assessed by linker-scanning analysis and site-directed mutagenesis. An analysis of expression of the ETS and GATA transcription factors showed that Erg, Fli-1 and GATA-2 are the most highly expressed factors in endothelial cells. Erg and GATA-2 directly control the expression of the endogenous VE-statin/egfl7 while Fli-1 probably exerts an indirect control, as assessed by RNA interference and chromatin immunoprecipitation. This first detailed analysis of the mechanisms that govern the expression of the VE-statin/egfl7 gene in endothelial cells pinpoints the specific importance of ETS and GATA factors in the specific regulation of genes in this cell lineage

    E-Cadherin Acts as a Regulator of Transcripts Associated with a Wide Range of Cellular Processes in Mouse Embryonic Stem Cells

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    We have recently shown that expression of the cell adhesion molecule E-cadherin is required for LIF-dependent pluripotency of mouse embryonic stem (ES) cells.In this study, we have assessed global transcript expression in E-cadherin null (Ecad-/-) ES cells cultured in either the presence or absence of LIF and compared these to the parental cell line wtD3.We show that LIF has little effect on the transcript profile of Ecad-/- ES cells, with statistically significant transcript alterations observed only for Sp8 and Stat3. Comparison of Ecad-/- and wtD3 ES cells cultured in LIF demonstrated significant alterations in the transcript profile, with effects not only confined to cell adhesion and motility but also affecting, for example, primary metabolic processes, catabolism and genes associated with apoptosis. Ecad-/- ES cells share similar, although not identical, gene expression profiles to epiblast-derived pluripotent stem cells, suggesting that E-cadherin expression may inhibit inner cell mass to epiblast transition. We further show that Ecad-/- ES cells maintain a functional Ξ²-catenin pool that is able to induce Ξ²-catenin/TCF-mediated transactivation but, contrary to previous findings, do not display endogenous Ξ²-catenin/TCF-mediated transactivation. We conclude that loss of E-cadherin in mouse ES cells leads to significant transcript alterations independently of Ξ²-catenin/TCF transactivation
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