An e-learning platform for delivering educational contents in a school environment

Learning is a continuous process, without end, which takes place throughout life, and is the result of the interaction of an individual with a physical external environment, a social context or with herself. In what new technologies may help improving and making more effective the interaction of an individual during his learning process? This paper describes the use of a platform for delivering educational contents to students, to put theories into practice through the use of an LMS and highlight the strengths and weaknesses that have these learning tools in a school environment, in which - besides its formative aspect - upbringing is important.learning management system, digital contents.

Control design for a voltage regulator in a single-phase grid-connected PV inverter

This work presents the design guidelines of a control for direct regulation of the voltage amplitude at the connection point of a single-phase gridconnected PV inverter. The parameters of such control are designed for ensuring locally asymptotic stability for a given range of the impedance. Usually, the design of the controllers are done by applying the drop method approximation. This work evaluates the application of another method, that consists in a linearization of the non-linear curve relating the amplitude of the voltage at the connection point with the injected active and reactive power. It has been studied the control strategy of drop method and new control strategy, which considers the real function and its linearization. Numerical simulations for the last method confirm the expected proper voltage regulation and the control robustness with respect to the grid impedance variations without the requirement of any estimation or measure of the actual impedance. This thesis shows, through a comparison between the drop method and the linearization method, what is the more realistic one. The results show that the linearization method is faster and has more accuracy than the drop method. This is more evident when one or more control parameters change

Long Distance GNSS-Denied Visual Inertial Navigation for Autonomous Fixed Wing Unmanned Air Vehicles: SO(3) Manifold Filter based on Virtual Vision Sensor

This article proposes a visual inertial navigation algorithm intended to diminish the horizontal position drift experienced by autonomous fixed wing UAVs (Unmanned Air Vehicles) in the absence of GNSS (Global Navigation Satellite System) signals. In addition to accelerometers, gyroscopes, and magnetometers, the proposed navigation filter relies on the accurate incremental displacement outputs generated by a VO (Visual Odometry) system, denoted here as a Virtual Vision Sensor or VVS, which relies on images of the Earth surface taken by an onboard camera and is itself assisted by the filter inertial estimations. Although not a full replacement for a GNSS receiver since its position observations are relative instead of absolute, the proposed system enables major reductions in the GNSS-Denied attitude and position estimation errors. In order to minimize the accumulation of errors in the absence of absolute observations, the filter is implemented in the manifold of rigid body rotations or SO (3). Stochastic high fidelity simulations of two representative scenarios involving the loss of GNSS signals are employed to evaluate the results. The authors release the C++ implementation of both the visual inertial navigation filter and the high fidelity simulation as open-source software.Comment: 27 pages, 14 figures. arXiv admin note: substantial text overlap with arXiv:2205.1324

in vitro models to evaluate the capacity of different sequestering agents to adsorb aflatoxins

Eight potential aflatoxin-sequestering agents (SAs) were tested for their ability to adsorb aflatoxin B1 (AfB1) and aflatoxin G1 (AfG1) in vitro. They belong to main SA classes: silicate minerals (calcium, magnesium and sodium bentonites, kaolinite, zeolite and clinoptinolite), activated carbon and yeast cell wall-derived. The AfB1 and AfG1 used in present work were extracted from a contaminated corn meal (82.21 mg/kg of AfB1 and 97.20 mg/kg of AfG11). Three single-concentration adsorption tests, consisting of a simply-water (W), a gastrointestinal simulating monogastric model (MM) and a ruminant model (RM), were used. The methods differed for dilution media, incubation steps and pH condition in which they were conducted. In particular, one step (2h at 39°C) at pH 7 for W; two steps (4h at 39°C) at pH 2 and 7 for MM; and a pre-incubation in rumen fluid (pH 7 for 2h at 39°C) + two steps (4h at 39°C) at pH 2 and 7 for RM, characterized each method. The AfB1:SA ratio (g/g) and dilution factor (ng of incubated AfB1:mL of volume) were chosen (1:500,000 and 4.1, respectively) to reflect field conditions. The AfB1 and AfG1 recovered in controls were 92.3% and 104.9% in W and 89.5% and 101.5% in MM; while in RM were 65.2% and 81.9%; respectively. This supported the idea of intrinsic rumen fluid factors could be involved in sequestering of aflatoxins. In the present study, three SAs (activated carbon, Mg bentonite and Na bentonite) were very efficient to sequester the available AfB1, with a sequestering activity of over 99.0% with each method. The Ca bentonite and clinoptinolite were able to bind available AfB1 in MM and RM methods, while they appeared inefficient (available AfB1 sequestered less than 80%) when W was used. The adsorption ability of zeolite was confirmed only with the W method. Ineffective or limited sequestering activity were obtained with kaolinite and yeast cell wall-derived products with each method. The AfB1 and AfG1 sequestering efficiencies observed in the present work resulted very similar showing strong and positive correlation (P<0.001) within methods (r=0.79, r=0.96 and r=0.99, respectively for W, MM and RM methods). The two simulated gastrointestinal methods (MM and RM, respectively) gave similar results and could be considered useful for in vitro pre-screening of potential sequestering agents. However, the major practical and analytical implications related to rumen fluid method suggested that MM method should be used

Fortalecer el Parlamento

El Parlamento no está bien evaluado por la ciudadanía. Tanto el Senado como la Cámara de Diputados no gozan de aprobación general, pese a la importante labor que realizan. Se aprecia más al parlamentario que se contribuyó a elegir y al cual se tiene acceso, que a la institución: es el llamado efecto Fenno, fenómeno que toma el nombre del profesor norteamericano que en la década del 70 analizó este fenómeno en el Congreso de los EE.UU. Así lo confirma la última Encuesta Nacional Bicentenario realizada por UC y Adimark

Morphostructural MRI abnormalities related to neuropsychiatric disorders associated to multiple sclerosis.

Multiple Sclerosis associated neuropsychiatric disorders include major depression (MD), obsessive-compulsive disorder (OCD), bipolar affective disorder, euphoria, pseudobulbar affect, psychosis, and personality change. Magnetic Resonance Imaging (MRI) studies focused mainly on identifying morphostructural correlates of MD; only a few anecdotal cases on OCD associated to MS (OCD-MS), euphoria, pseudobulbar affect, psychosis, personality change, and one research article on MRI abnormalities in OCD-MS have been published. Therefore, in the present review we will report mainly on neuroimaging abnormalities found in MS patients with MD and OCD. All together, the studies on MD associated to MS suggest that, in this disease, depression is linked to a damage involving mainly frontotemporal regions either with discrete lesions (with those visible in T1 weighted images playing a more significant role) or subtle normal appearing white matter abnormalities. Hippocampal atrophy, as well, seems to be involved in MS related depression. It is conceivable that grey matter pathology (i.e., global and regional atrophy, cortical lesions), which occurs early in the course of disease, may involve several areas including the dorsolateral prefrontal cortex, the orbitofrontal cortex, and the anterior cingulate cortex whose disruption is currently thought to explain late-life depression. Further MRI studies are necessary to better elucidate OCD pathogenesis in MS

Technical note: Evaluation of a novel enzymatic method to predict in situ undigested neutral detergent fiber of forages and nonforage fibrous feeds.

ABSTRACT The purpose of this study was to optimize the conditions of a previously proposed enzymatic method used to estimate in situ undigested neutral detergent fiber (uNDF). We used a multi-step enzymatic approach, in which samples were first solubilized in NaOH solutions as a preincubation (PreInc) phase. After rinsing, samples were incubated (24 h at 39°C) in a buffered solution (pH 6) containing hemicellulase, cellulase, and Viscozyme L enzymes (Sigma-Aldrich s.r.l., Milan, Italy), followed by incubation (24 h at 39°C) in a buffered solution (pH 5) containing xylanase. Two sets of experiments were performed: a calibration trial (that tested different PreInc conditions on 9 selected forages) and a validation trial (that verified the results by testing multiple samples of 6 different forage types and a group of fibrous by-products). In the calibration trial, samples (300 mg in Ankom F57 filter bags; Ankom Technology Corp., Fairport, NY) were preincubated at 39°C in a 0.1 M NaOH solution for 90, 180, or 240 min, or in 0.2, 0.5, 1.0, or 2.0 M NaOH solution for 90 min. The results indicated that the best PreInc method, in terms of intra-laboratory repeatability and estimation of reference in situ values, was 90 min in a 0.2 M NaOH solution. Thus, we used this PreInc condition to determine enzymatic uNDF of 257 samples in the validation trial. Although the selected method generally had good accuracy in predicting in situ uNDF, inconsistencies were noted for certain forage types. Overall, when enzymatic uNDF was used to predict the in situ uNDF of all samples, the regression was satisfactory (intercept = 7.098, slope = 0.920, R2 = 0.73). The regression models developed for alfalfa hays, corn silages, and small grain silages had also acceptable regression performances and mean square error of prediction (MSEP) values, and the main sources of MSEP variation were error due to incomplete (co)variation and random error. Even when R2 values were >0.70, the MSEP value of the regression model for grass hays was 149.55, and that for nonforage fibrous feeds was 155.16. Although enzymatic uNDF partially overestimated the in situ uNDF, particularly in grass silages, the proposed procedure seems to be promising for accurately predicting in situ uNDF, because it generally had good repeatability and provided satisfactory estimates of in situ uNDF