Chua´s circuit and its characterization as a filter

"This article deals with Chuaʼs circuit characterization from the point of view of a filter based on the concept of piecewise linear functions. Furthermore, experiments are developed for teaching electronic systems that can be used for novel filtering concepts. The frequency range in which they are tested is from $20\;{\rm Hz}$ to $20\;{\rm kHz}$, due to the audio spectrum comprised in this frequency range. The node associated with the capacitor and Chuaʼs diode is used as input, and the node for another capacitor and the coil is used as output, thereby establishing one input–output relationship for each system case given by the piecewise linear functions. The experimental result shows that Chuaʼs circuit behaves as a bandpass filter-amplifier, with a maximum frequency around $3\;{\rm kHz}$ and bandwidth between $1.5\;{\rm kHz}$ and $5.5\;{\rm kHz}$. The results presented in this paper can motivate engineering students to pursue applications of novel electrical circuits based on topics that are of potential interest in their future research studies.

Multidisciplinary teaching of Biotechnology and Omics sciences

In the last years, there was a great boom in the Omics fields that have developed as multidisciplinary sciences. They use laboratory techniques related to Biology and Chemistry but also Bioinformatics tools. However, the developmental progress of these disciplines has led that much of undergraduate studies related to Biology have curricula that become outdated. From this point of view, it is necessary to focus the students to the fundamentals and techniques of complementary disciplines that will be essentials for the understanding of the Omics sciences. In the present work, we have developed a new teaching approach for Biochemistry, Biology and Bioinformatics students. They formed interdisciplinary working groups. These groups have prepared and presented communications about different techniques or methods in Molecular Biology, Omics or Bioinformatics participating in a technical meeting. This learning strategy “I do and I learn” has enabled to the students a first contact with the scientific communication including the approach to the scientific literature to acquire technical knowledge. The cooperation between students from different disciplines has enriched their point of view and even has been used in some practical master’s works.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Response to water deficit on tree growth from urban forestry of Mendoza city : comparative analysis in sapling trees

El objetivo del trabajo fue evaluar la respuesta de plantas jóvenes de cuatro especies forestales urbanas a diferentes niveles de déficit hídrico. El ensayo se realizó en vivero, durante tres ciclos vegetativos, con plantas de Platanus x hispanica cv. acerifolia (plátano), Morus alba (morera), Fraxinus americana (fresno americano) y Acacia visco (visco). Los tratamientos de riego fueron: control (reposición del 100% transpirado); riego deficitario moderado (reposición del 66% transpirado) y riego deficitario severo (reposición del 33% transpirado). Las variables de respuesta evaluadas fueron altura, diámetro de tallos, área foliar y ancho de anillos de crecimiento. Las plantas bajo riego deficitario severo presentaron disminuciones en todos los parámetros de crecimiento considerados. Acacia visco resultó con crecimientos comparables al control, bajo riego deficitario equivalente al 66% del agua transpirada, con lo cual puede ser considerada especie de interés para forestaciones en condiciones de estrés hídrico moderado.The objective was to evaluate the young plants response of four urban forest species at different levels of water deficit. The manipulative experiment was conducted in nursery for three growing seasons, with saplings of Platanus x hispanica cv. acerifolia (London plane), Morus alba (mulberry), Fraxinus americana (American ash) and Acacia visco (visco). The catering treatments were: control (replacement of 100% water transpired), moderate deficit watering (replacement of 66% water transpired) and severe deficit watering (replacement of 33% water transpired). Response variables measured were height, stem diameter, leaf area and annual tree-rings width. Plants under severe deficit watering showed decreases in all growth parameters considered. Acacia visco under moderate deficit watering equivalent to 66% of transpired water had a growth comparable to control. Therefore, this specie could be considered relevant to new forestations in moderate water stress conditions.Fil: Martínez, Claudia. CONICET. CRICYT. INCIHUSA (Instituto de Ciencias Sociales, Humanas y Ambientales)Fil: Cavagnaro, Juan Bruno. Universidad Nacional de Cuyo. Facultad de Ciencias AgrariasFil: Roig Juñent, Fidel A.. Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA).Fil: Cantón, María Alicia. CONICET. CRICYT. INCIHUSA (Instituto de Ciencias Sociales, Humanas y Ambientales