La formación de competencias digitales de estudiantes de profesorados universitarios : La estrategia de e-actividades en un modelo de aula extendida

Es un hecho que las Tecnologías de la Información y la Comunicación (TIC) han modificado nuestras prácticas sociales. También lo es que los jóvenes nacidos en los últimos años parecen haberse apropiado de ellas con gran habilidad. Sin embargo, luego de varios años enseñando TIC a alumnos de profesorados universitarios de la Facultad de Humanidades y Ciencias de la Educación (FaHCE) de la Universidad Nacional de la Plata, observamos que sus desempeños en relación a dichas tecnologías no parecía ni suficiente ni apropiado de acuerdo a los estándares internacionales y regionales vigentes de competencias digitales para el nivel universitario. Como estrategia didáctica superadora implementamos un diseño de instrucción basado en el modelo de aula extendida con e-actividades, buscando ampliar el contacto de los estudiantes con la propuesta de la asignatura, cuantitativa y cualitativamente. Luego, al haber obtenido algunas señales auspiciosas en cuanto el desarrollo de las competencias digitales de nuestros alumnos, nos formulamos la hipótesis que orientó nuestro trabajo: Las e-actividades en un modelo de aula extendida podrían favorecer el desarrollo de las competencias digitales académicas de los estudiantes de profesorados universitarios. Emprendimos entonces esta investigación que, con el objetivo principal de mejorar las competencias digitales de nuestros estudiantes, dirigimos en dos direcciones: Indagar cuáles son los niveles de conocimientos digitales deseables para un alumno futuro docente del siglo XXI. En base a la revisión documental sobre este tema, consideramos que un estudiante de profesorado universitario posee competencias digitales si, además de dominarlas, las valora y es consciente de cómo ellas contribuyen a su formación académica y de cómo seguirán haciéndolo en su desempeño profesional futuro, consciente al mismo tiempo de que las TIC no poseen un potencial transformador en sí mismas, sino en función del uso que se haga de ellas. Comprobar la veracidad de nuestra hipótesis sobre los potenciales beneficios de las e-actividades en la formación digital de nuestros estudiantes, y de verificarse este supuesto, destacar las condiciones de calidad según las cuales deberían diseñarse

La formación de competencias digitales de estudiantes de profesorados universitarios : La estrategia de e-actividades en un modelo de aula extendida

Es un hecho que las Tecnologías de la Información y la Comunicación (TIC) han modificado nuestras prácticas sociales. También lo es que los jóvenes nacidos en los últimos años parecen haberse apropiado de ellas con gran habilidad. Sin embargo, luego de varios años enseñando TIC a alumnos de profesorados universitarios de la Facultad de Humanidades y Ciencias de la Educación (FaHCE) de la Universidad Nacional de la Plata, observamos que sus desempeños en relación a dichas tecnologías no parecía ni suficiente ni apropiado de acuerdo a los estándares internacionales y regionales vigentes de competencias digitales para el nivel universitario. Como estrategia didáctica superadora implementamos un diseño de instrucción basado en el modelo de aula extendida con e-actividades, buscando ampliar el contacto de los estudiantes con la propuesta de la asignatura, cuantitativa y cualitativamente. Luego, al haber obtenido algunas señales auspiciosas en cuanto el desarrollo de las competencias digitales de nuestros alumnos, nos formulamos la hipótesis que orientó nuestro trabajo: Las e-actividades en un modelo de aula extendida podrían favorecer el desarrollo de las competencias digitales académicas de los estudiantes de profesorados universitarios. Emprendimos entonces esta investigación que, con el objetivo principal de mejorar las competencias digitales de nuestros estudiantes, dirigimos en dos direcciones: Indagar cuáles son los niveles de conocimientos digitales deseables para un alumno futuro docente del siglo XXI. En base a la revisión documental sobre este tema, consideramos que un estudiante de profesorado universitario posee competencias digitales si, además de dominarlas, las valora y es consciente de cómo ellas contribuyen a su formación académica y de cómo seguirán haciéndolo en su desempeño profesional futuro, consciente al mismo tiempo de que las TIC no poseen un potencial transformador en sí mismas, sino en función del uso que se haga de ellas. Comprobar la veracidad de nuestra hipótesis sobre los potenciales beneficios de las e-actividades en la formación digital de nuestros estudiantes, y de verificarse este supuesto, destacar las condiciones de calidad según las cuales deberían diseñarse

Visual demonstration of the ionic strength effect in the classroom: the Debye-Hückel limiting law

The effects of ionic strength on ions in aqueous solutions are quite relevant, especially for biochemical systems, in which proteins and amino acids are involved. The teaching of this topic and more specifically, the Debye-Hückel limiting law, is central in chemistry undergraduate courses. In this work, we present a description of an experimental procedure based on the color change of aqueous solutions of bromocresol green (BCG), driven by addition of electrolyte. The contribution of charge product (z+|z-|) to the Debye-Hückel limiting law is demonstrated when the effects of NaCl and Na2SO4 on the color of BCG solutions are compared.

X-ray diffraction characterisation of expanded austenite and ferrite in plasma nitrided stainless steels

The S phase, known as expanded austenite, is formed on the surfaces of austenitic stainless steels that are nitrided under low temperature plasma. A similar phase was observed for nitrided ferritic stainless steels and was designed as expanded ferrite or ferritic S phase. The authors treated samples of austenitic AISI 304L and AISI 316L and ferritic AISI 409 stainless steels by plasma nitriding at different temperatures and then studied the structural, morphological, chemical and corrosion characteristics of the modified layers by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and electrochemical tests. For both austenitic AISI 304L and AISI 316L stainless steels, the results showed that a hard S phase layer was formed on the surfaces, promoting an anodic polarisation curve displacement to higher current density values that depend on the plasma nitriding temperature. A layer having a high amount of nitrogen was formed on the ferritic AISI 409 stainless steel. X-ray diffraction measurements indicated high strain states for the modified layers formed on the three stainless steels, being more pronounced for the ferritic S phase.

Anaerobic fluidized bed reactor with expanded clay as support for hydrogen production through dark fermentation of glucose

This study evaluated hydrogen production in an anaerobic fluidized bed reactor (AFBR) fed with glucose-based synthetic wastewater. Particles of expanded clay (2.8-3.35 mm) were used as a support material for biomass immobilization. The reactor was operated with hydraulic retention times (HRT) ranging from 8 to 1 h. The hydrogen yield production increased from 1.41 to 2.49 mol H(2) Mol(-1) glucose as HRT decreased from 8 to 2 h. However, when HRT was 1 h, there was a slight decrease to 2.41 mol H(2) Mol(-1) glucose. The biogas produced was composed of H(2) and CO(2), and the H(2) content increased from 8% to 35% as HRT decreased. The major soluble metabolites during H(2) fermentation were acetic acid (HAc) and butyric acid (HBu), accounting for 36.1-53.3% and 37.7-44.9% of total soluble metabolites, respectively. Overall, the results demonstrate the potential of using expanded clay as support material for hydrogen production in AFBRs. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

Cytokine expanded myeloid precursors function as regulatory antigen presenting cells and induce tolerance through IL-10 producing regulatory T cells

The initiation of graft vs. host disease (GVHD) after stem cell transplantation is dependent on direct antigen presentation by host antigen presenting cells (APC) while the effect of indirect antigen presentation by donor APC is unknown. We have studied the role of indirect antigen presentation in allogenic responses by adding populations of cytokine-expanded donor APC to haematopoietic grafts that would otherwise induce lethal GVHD. Progenipoietin-1 (a synthetic G-CSF/Flt-3 L molecule) and G-CSF expanded myeloid DC, plasmacytoid DC and a novel granulocyte-monocyte precursor population (GM) that differentiate into class IIpos, CD80/CD86pos, CD40neg APC during GVHD. Whereas addition of plasmacytoid and myeloid donor DC augmented GVHD, GM cells induced transplant tolerance via MHC class II restricted generation of IL-10-secreting regulatory T cells. Thus a population of cytokine expanded granulocyte-monocyte precursors function as regulatory antigen presenting cells, suggesting that G-CSF derivatives may have application in disorders characterised by a loss of self-tolerance.

A Prospective Study of Conventional and Expanded Coagulation Indices in Predicting Ulcer Bleeding After Variceal Band Ligation

BACKGROUND & AIMS: There is controversy over whether coagulation status predicts bleeding caused by ulceration after esophageal varices band ligation (EVL). METHODS: EVL was performed for primary (n = 45) or secondary (n = 105) prophylaxis in 150 patients with cirrhosis (Child A, n = 74, 49%; Child B, n = 42, 28%; Child C, n = 34, 23%). International normalized ratio (INR) and platelet counts were assessed in all. In 92 patients, levels of factor V, fibrinogen, D-dimer, protein C and protein S, von Willebrand factor, and thromboelastography (TEG) were assessed. Platelet count < 50 x 10(3)/mm(3) and INR > 1.5 were considered high-risk cutoff for bleeding. Conversely, platelet count >= 50 x 10(3)/mm(3) with INR <= 1.5 were safe cutoffs. RESULTS: Overall, 11 patients (7.3%) had post-EVL ulcer bleeding. Bleeding occurred in S patients with Child A/B (4.3%) and 6 patients with Child C (17%) (P = .0174 for Child A/B versus Child C). Eight patients with bleeding were among the 110 below the cutoff for INR and platelet count, whereas only 3 of the patients with bleeding were among the 40 patients with purported high-risk values (P = 1.0). Among the 92 patients with expanded coagulation tests, bleeding occurred in S. There was no difference in any of the coagulation parameters, including overall TEG patterns, between patients who did and did nor bleed. CONCLUSIONS: Post-EVL ulcer bleeding was associated with Child C status but not with conventional or expanded coagulation indices in cirrhotic patients without renal failure or infection undergoing elective EVL. These results call into question the common use of prophylactic procoagulants in the elective setting.

Expanded protocol of orofacial myofunctional evaluation with scores: Validity and reliability

Objective: Clinical evaluation of the stomatognathic system is indispensable for the diagnosis of orofacial myofunctional disorders. In order to obtain a more precise diagnosis, the protocol of orofacial myofunctional evaluation with scores (OMES protocol) (Int. J. Pediatr. Otorhinolaryngol. 72 (2008) 367-375) was expanded in terms of number of items and scale amplitude. The proposal of this study is to describe the expanded OMES protocol (OMES-E) for the evaluation of children. Validity of the protocol, reliability of the examiners and agreement between them were analyzed, as also were the sensitivity, specificity and predictive values of the instrument. Methods: The sample consisted of videorecorded images of 50 children, 25 boys (mean age = 8.4 years, SD = 1.8) and 25 girls (mean age = 8.2 years, SD = 1.7) selected at random from 200 samples. Three speech therapists prepared for orofacial myofunctional evaluation participated as examiners (E). The OMES and OMES-E protocols were used for evaluation on different days. E1 evaluated all images, E2 analyzed children with recordings from 1 to 25 and E3 analyzed children with recordings from 26 to 50. The validity of OMES-E was analyzed by comparing the instrument to the OMES protocol using the Pearson correlation test complemented with the split-half reliability test (p < 0.05). The linear weighted Kappa coefficient of agreement (Kw`), the sensitivity, specificity and predictive values and the prevalence of OMD were calculated. Results: There was a statistically significant correlation between the OMES and OMES-E protocols (0.79 > r < 0.94, p < 0.01) and a significant test-retest correlation with the OMES-E (0.75 > r < 0.86, p < 0.01), with a reliability range of 0.86-0.93. The correlation and reliability coefficients between examiners were: E1 x E2 (r = 0.74, 0.84), E1 x E3 (r = 0.70, 0.83) (p < 0.01). Kw` coefficients with moderate and good strength predominated. The OMES-E protocol presented mean sensitivity = 0.91, specificity = 0.77, positive predictive value = 0.87 and negative predictive value = 0.85. The mean prevalence of OMD was 0.58. Conclusion: The OMES-E protocol is valid and reliable for orofacial myofunctional evaluation. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Influence of Osteopenia in Autogenous Bone Graft Healing With or Without Expanded Polytetrafluoroethylene Membranes: Histologic and Histomorphometric Study in Rats

Purpose: The aim of this study was to quantitatively evaluate and qualitatively describe autogenous bone graft healing with or without an expanded polytetrafluoroethylene (e-PTFE) membrane in ovariectornized rats. Materials and Methods: Eighty Wistar rats, weighing approximately 300 g each, were used. A graft was obtained from the parietal bone and fixed to the sidewall of each animal`s left mandibular ramus. The animals were randomly divided into four experimental groups (n = 20 in each group): group 1, sham operated and autogenous bone graft only- group 2, sham operated and autogenous bone graft covered by e-PTFE membrane; group 3, ovariectornized (OVX) and autogenous bone graft only- group 4, OVX and autogenous bone graft covered by e-PTFE membrane. The animals were sacrificed at five different time points: immediately after grafting or at 7, 21, 45, or 60 days after grafting. Histologic examination and morphometric measurement of the sections were performed, and values were submitted to statistical analyses. Results: Both groups (sham and OVX) experienced loss of the original graft volume when it was not covered by the membrane, whereas use of the membrane resulted in additional bone formation beyond the edges of the graft and under the membrane. Histologic analysis showed integration of the grafts in all animals, although a larger number of marrow spaces was found in OVX groups. Conclusions: Association of bone graft with an e-PTFE membrane resulted in maintenance of its original volume as well as formation of new bone that filled the space under the membrane. Osteopenia did not influence bone graft repair, regardless of whether or not it was associated with e-PTFE membrane, but descriptive histologic analysis showed larger numbers of marrow spaces in the bone graft and receptor bed and formation of new bone in the OVX animals. INT J ORAL MAXILLOFAC IMPLANTS 2009;24:1074-1082