Electrònica digital : una experiència d'aprenentatge col·laboratiu

En el curs 2006-2007, a l'Escola Universitària Salesiana de Sarrià, s'ha realitzat una experiència d'aprenentatge col·laboratiu en l'assignatura d'Electrònica Digital del primer quadrimestre del primer curs. En l'esquema d'aprenentatge, les sessions de teoria s'ha fet en grups de 3-4 persones, que han format un grup consolidat durant tot el quadrimestre. La metodologia general de l'assignatura s'ha basat en l'aprenentatge col·laboratiu. El format habitual de treball ha estat el següent: el professor explicava a l'inici de cada sessió durant 20-30 min i proposava als grup els problemes i exercicis a desenvolupar durant la resta de la classe i el treball individual i en grup fora de l'aula. Les activitats més importants han estat la realització d'exercicis i problemes de nivell de dificultat diversa, així com un projecte d'aplicació. També s'ha realitzat recerca d'informació. Per avaluar s'ha utilitzat la metodologia de l'avaluació continua, tenint en compte tant el treball realitzat en grup com el nivell d'aprenentatge individual. Finalment, en aquesta comunicació també s'exposen els resultats obtinguts, tant pel que fa a l'assistència i participació com el rendiment acadèmic.A collaborative learning experience in Digital Electronics with freshmen students has been carried out at Escola Universitària Salesiana de Sarrià (EUSS) along the academic year 2006-2007. Learning has been focused on students using collaborative techniques in class. Three or four established groups have been created to work in class. Teachers started each session by giving students a short explanation on how to deal with the activity, and provided them with exercises and problems to work with both in class and as homework either individually or in groups. The main activities have consisted of different levels problem solving, information research for knowledge creation as long as an application project. Continuous evaluation has been chosen in order to qualify students taking into account individual and group learning. Finally, we show the results of our experience from three different points of view, such as attendance, participation and outcome

Temperature compensation of ultrasonic velocity during the malolactic fermentation process

Ultrasonic properties of materials present a strong dependence on temperature and in turn the ultrasonic velocity of propagation in the material under test. It is precisely for this reason that most ultrasonic measurements are often carried out with thermostated samples by using either water tanks or climate chambers. This approach is viable in a laboratory and when the measured or characterized samples are relatively small. However, this procedure is highly improbable to be applied when in situ measurements in industrial environments must be performed. This goes for the case of, for example, ultrasonic velocity measurements in wine while it is performing malolactic fermentation inside a tank of hundreds of thousands of litres. In this paper two different practical approaches to temperature compensation are studied. Then, the two temperature compensation methods are applied to the measured ultrasonic velocity values along a whole malolactic fermentation process. The results of each method are discussed.Peer ReviewedPostprint (author's final draft

Electrònica digital : una experiència d'aprenentatge col·laboratiu

En el curs 2006-2007, a l'Escola Universitària Salesiana de Sarrià, s'ha realitzat una experiència d'aprenentatge col·laboratiu en l'assignatura d'Electrònica Digital del primer quadrimestre del primer curs. En l'esquema d'aprenentatge, les sessions de teoria s'ha fet en grups de 3-4 persones, que han format un grup consolidat durant tot el quadrimestre. La metodologia general de l'assignatura s'ha basat en l'aprenentatge col·laboratiu. El format habitual de treball ha estat el següent: el professor explicava a l'inici de cada sessió durant 20-30 min i proposava als grup els problemes i exercicis a desenvolupar durant la resta de la classe i el treball individual i en grup fora de l'aula. Les activitats més importants han estat la realització d'exercicis i problemes de nivell de dificultat diversa, així com un projecte d'aplicació. També s'ha realitzat recerca d'informació. Per avaluar s'ha utilitzat la metodologia de l'avaluació continua, tenint en compte tant el treball realitzat en grup com el nivell d'aprenentatge individual. Finalment, en aquesta comunicació també s'exposen els resultats obtinguts, tant pel que fa a l'assistència i participació com el rendiment acadèmic.A collaborative learning experience in Digital Electronics with freshmen students has been carried out at Escola Universitària Salesiana de Sarrià (EUSS) along the academic year 2006-2007. Learning has been focused on students using collaborative techniques in class. Three or four established groups have been created to work in class. Teachers started each session by giving students a short explanation on how to deal with the activity, and provided them with exercises and problems to work with both in class and as homework either individually or in groups. The main activities have consisted of different levels problem solving, information research for knowledge creation as long as an application project. Continuous evaluation has been chosen in order to qualify students taking into account individual and group learning. Finally, we show the results of our experience from three different points of view, such as attendance, participation and outcome

Real-Time Detection of the Bacterial Biofilm Formation Stages Using QCM-Based Sensors

Bacterial biofilms are a major cause of harm related to medical infections and biofouling. Thus, 80% of total infections are caused by biofilm-forming microorganisms. Consequently, knowledge of biofilm formation stages is crucial to develop effective treatments to prevent their formation in medical implants, tools, and devices. For this purpose, quartz crystal microbalance (QCM) sensors are becoming a good alternative to analytical methods for the real-time monitoring of bacterial growth in liquid media culture. In a previous paper, the authors described an affordable multi-channel measurement instrument based on QCM sensors. However, in order to validate its correct operation, complementary experimental measurements based on bacterial biofilm growth were performed. In this work, the experimental measurements that allow the identification of the different biofilm formation stages are described. The results obtained are discussed

Comparison between sine wave fitting and zero- crossing methods applied to QCM impedance measurements

This paper presents a comparison between two algorithms for sinusoidal signal characterization applied to QCM impedance measurements. These algorithms are the zero crossing and peak detection method and the 7 parameters sine-fitting method. Simulation and experimental results from both methods are shown in order to determine which method provides the best performance in terms of accuracy. Obtaining a precise value of the QCM impedance depends directly on the precise measurement of the amplitude and phase of two sinusoidal voltages. It was found that the sine-fitting method achieves better results without an excessive associated computational burden. These results will be applied to the development of a new technique for biofilm characterization based on multiple QCM impedance measurements.Peer ReviewedPostprint (published version

Temperature compensation of ultrasonic velocity during the malolactic fermentation process

Ultrasonic properties of materials present a strong dependence on temperature and in turn the ultrasonic velocity of propagation in the material under test. It is precisely for this reason that most ultrasonic measurements are often carried out with thermostated samples by using either water tanks or climate chambers. This approach is viable in a laboratory and when the measured or characterized samples are relatively small. However, this procedure is highly improbable to be applied when in situ measurements in industrial environments must be performed. This goes for the case of, for example, ultrasonic velocity measurements in wine while it is performing malolactic fermentation inside a tank of hundreds of thousands of litres. In this paper two different practical approaches to temperature compensation are studied. Then, the two temperature compensation methods are applied to the measured ultrasonic velocity values along a whole malolactic fermentation process. The results of each method are discussed.Peer Reviewe

Recurring renal lithiasis due to Dent’s disease

Dent's disease is a rare cause of hypercalciuria and recurring urolithiasis. Patients with this disease have elevated bone resorption due to the presence of parathormone (PTH) in the urine. We describe the case of a 21-year-old male with hypercalciuria, elevated bone resorption and recurring bilateral urolithiasis that achieves radiological and clinical stability with percutaneous nephrolithotomy (PNL) and medical treatment with hydrochlorothiazide, potassium-citrate and phytate