121 research outputs found
Aprendiendo de la Evaluación entre Compañeros
La evaluación continua forma parte de la metodología inductiva que ya llevamos unos años incorporando en nuestras aulas en el marco del EEES. Indudablemente, las tareas de evaluación que se derivan de esta metodología suponen un importante incremento de dedicación por parte del profesor, que además debe intentar proporcionar un feedback provechoso para el alumno. Sin embargo, a menudo constatamos que nuestros esfuerzos no se reflejan en el aprendizaje del estudiante. Una forma de intentar que el feedback que se deriva de la evaluación continua mejore el aprendizaje, es involucrar al estudiante en las tareas de evaluación. En este trabajo se describe la experiencia docente sobre evaluación entre compañeros en la asignatura de Lógica de segundo curso del grado en Ingeniería Informática.The use of continuous assessment is part of the inductive methodology which we have included in our teaching activity over the last years in the framework of the EEES. Undoubtedly, the evaluation tasks derived from this methodology mean a significant increase in the amount of work for professors. Moreover, such activity should provide beneficial effects amongst the students. However, our efforts often have not the desired repercussion in the students learning process. A way to overcome this problem is to involve the students in the evaluation tasks. In this work we describe a teaching experience about peer assessment in the subject Logic of Second Course in Computer Science
Magnetic Studies on Spinel Ferrite Nanoparticles and Bulk Samples Synthesized by Citrate Combustion Route
We report structural, microstructural and magnetic studies of ZnFe2O4, MnFe2O4 and mixed Mn-Ni-Zn ferrites in nanoparticles and bulk forms. Polycrystalline samples were prepared by citrate combustion synthesis, which resulted in homogeneous and nanograin powders. Particle sizes estimated from the XRD and SEM were found to be below 100 nm for the calcined powders (600 degrees C) and above 300 nm range for the sintered (1200 degrees C) samples. Substitution of Ni and Zn for Mn enhanced the saturation magnetization and coercivity, because of the redistribution between octahedral and tetrahedral iron sites. Curie temperature were found to be higher for the calcined powders as compared to corresponding sintered samples due to particle size effects
Synthesis Control of Charge Separation at Anatase TiO2 Thin Films Studied by Transient Surface Photovoltage Spectroscopy
For the efficient photocatalytic oxidation of organic pollutants at surfaces of semiconductors, photogenerated holes shall be separated toward the surface and transferred to reactive surface sites, whereas the transfer of photogenerated electrons toward the surface shall be minimized. In this Research Article, the identification of suitable synthesis control of charge separation combined with an in depth understanding of charge kinetics and trapping passivation mechanisms at the related surfaces can provide tremendous opportunities for boosting the photocatalytic performance. In this work, a comprehensive transient surface photovoltage spectroscopy study of charge separation at anatase TiO2 thin films, synthesized by ultrasonic spray pyrolysis from titanium IV isopropoxide TTIP acetylacetone AcacH based precursor is reported. By varying the amount of AcacH in the precursor solution, an experimental approach of synthesis control of the charge transfer toward TiO2 surface is provided for the first time. An increased amount of AcacH in the precursor promotes transition from preferential fast electron to preferential fast hole transfer toward anatase surface, correlating with a strong increase of the photocatalytic decomposition rate of organic pollutants. Suitable mechanisms of AcacH induced passivation of electron traps at TiO2 surfaces are analyzed, providing a new degree of freedom for tailoring the properties of photocatalytic system
Placing the Fijian Honeyeaters within the meliphagid radiation: implications for origins and conservation
Understanding the evolutionary relationships of threatened species provides an important framework for
making decisions about their conservation. However, unrecognised problems with the underlying phylogenetic analyses
may bias the decision-making process. Recent phylogenetic studies have improved our understanding of Meliphagidae,
but also indicate discordance between molecular datasets. Here, we examine the causes of this discordance using
maximum likelihood tree-building and network analyses of identically sampled datasets for four genetic loci. Our results
suggest that while we can be reasonably confident of relationships within species groups, discordance within and between
molecular datasets tends to obscure relationships towards the base of the meliphagid tree. This ongoing uncertainty likely
reflects differences in the sampling of markers and taxa between previously published analyses. To avoid the problems of
conflicting data we used divergence time analyses of only the most densely sampled marker, NADH-ubiquinone
oxidoreductase chain 2, to investigate the age and origins of the Fijian Meliphagidae. Our analyses suggest two temporally
distinct colonisations of the Fijian archipelago. The large-bodied honeyeaters arrived ,15.6 million years ago,
subsequently diversifying and spreading to Tonga and Samoa. In contrast, Myzomela appears to have arrived within
the last 5.0 million years. The phylogenetic results therefore imply that conserving the evolutionary diversity of
Meliphagidae in Polynesia requires that effort be spread across both the currently recognised taxa and geographical range
Воспитание толерантности в процессе преподавания гуманитарных дисциплин
Objective: To assess whether patient characteristics add to the fetal fibronectin test and cervical length measurement in the prediction of preterm delivery in symptomatic women. Study design: A nationwide prospective cohort study was conducted in all ten perinatal centres in the Netherlands. Women with symptoms of preterm labour between 24 and 34 weeks gestation with intact membranes were invited. In all women qualitative fibronectin testing (0.050 tig/mL cut-off) and cervical length measurement were performed. Only singleton pregnancies were included in this analysis. Logistic regression was used to construct two multivariable models to predict spontaneously delivery within 7 days: a model including cervical length and fetal fibronectin as predictors, and an extended model including all potential predictors. The models were internally validated using bootstrapping techniques. Predictive performances were assessed as the area under the receiver operator characteristic curve (AUC) and calibration plots. We compared the models' capability to identify women with a low risk to deliver within 7 days. A risk less than 5%, corresponding to the risk for women with a cervical length of at least 25 mm, was considered as low risk. Results: Seventy-three of 600 included women (12%) had delivered spontaneously within 7 days. The extended model included maternal age, parity, previous preterm delivery, vaginal bleeding, C-reactive protein, cervical length, dilatation and fibronectin status. Both models had high discriminative performances (AUC of 0.92 (95% CI 0.88-0.95) and 0.95 (95% CI 0.92-0.97) respectively). Compared to the model with fibronectin and cervical length, our extended model reclassified 38 women (6%) from low risk to high risk and 21 women (4%) from high risk to low risk. Preterm delivery within 7 days occurred once in both the reclassification groups. Conclusion: In women with symptoms of preterm labour before 34 weeks gestation, a model that integrates maternal characteristics, clinical signs and laboratory tests, did not predict delivery within 7 days better than a model with only fibronectin and cervical length. (C) 2015 Elsevier Ireland Ltd. All rights reserved
CapZ-lipid membrane interactions: a computer analysis
BACKGROUND: CapZ is a calcium-insensitive and lipid-dependent actin filament capping protein, the main function of which is to regulate the assembly of the actin cytoskeleton. CapZ is associated with membranes in cells and it is generally assumed that this interaction is mediated by polyphosphoinositides (PPI) particularly PIP(2), which has been characterized in vitro. RESULTS: We propose that non-PPI lipids also bind CapZ. Data from computer-aided sequence and structure analyses further suggest that CapZ could become partially buried in the lipid bilayer probably under mildly acidic conditions, in a manner that is not only dependent on the presence of PPIs. We show that lipid binding could involve a number of sites that are spread throughout the CapZ molecule i.e., alpha- and beta-subunits. However, a beta-subunit segment between residues 134–151 is most likely to be involved in interacting with and inserting into lipid membrane due to a slighly higher ratio of positively to negatively charged residues and also due to the presence of a small hydrophobic helix. CONCLUSION: CapZ may therefore play an essential role in providing a stable membrane anchor for actin filaments
ZnO Nanorods via Spray Deposition of Solutions Containing Zinc Chloride and Thiocarbamide
In this work we present the results on formation of ZnO nanorods prepared by spray of aqueous solutions containing ZnCl2and thiocarbamide (tu) at different molar ratios. It has been observed that addition of thiocarbamide into the spray solution has great impact on the size, shape and phase composition of the ZnO crystals. Obtained layers were characterized by scanning electron microscopy (SEM) equipped with energy selected backscattered electron detection system (ESB), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). Small addition of thiocarbamide into ZnCl2solution (ZnCl2:tu = 1:0.25) supports development of significantly thinner ZnO nanorods with higher aspect ratio compared to those obtained from ZnCl2solution. Diameter of ZnO rods decreases from 270 to 100 nm and aspect ratio increases from ∼2.5 to 12 spraying ZnCl2and ZnCl2:tu solutions, respectively. According to XRD, well crystallized (002) orientated pure wurtzite ZnO crystals have been formed. However, tiny ‘spot’—like formations of ZnS were detected on the side planes of hexagonal rods prepared from the thiocarbamide containing solutions. Being adsorbed on the side facets of the crystals ZnS inhibits width growth and promotes longitudinalc-axis growth
Life and living in advanced age: a cohort study in New Zealand - Te Puāwaitanga o Nga Tapuwae Kia Ora Tonu, LiLACS NZ: Study protocol
The number of people of advanced age (85 years and older) is increasing and health systems may be challenged by increasing health-related needs. Recent overseas evidence suggests relatively high levels of wellbeing in this group, however little is known about people of advanced age, particularly the indigenous Māori, in Aotearoa, New Zealand. This paper outlines the methods of the study Life and Living in Advanced Age: A Cohort Study in New Zealand. The study aimed to establish predictors of successful advanced ageing and understand the relative importance of health, frailty, cultural, social & economic factors to successful ageing for Māori and non-Māori in New Zealand
Transfer of passive immunity and serum proteinogram in the first six months of life of Criollo Lageano and black and white holstein calves
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