a M. Ros

Sliding Mode Control in a Bioreactor Model

This article deals with an example of nonlinear control systems and the interlacing between a biochemical system, the mathematical model and the constrains derived from the discrete implementation of a continuous control policy. The theory is developed on a simplified model of a bioreactor to be regulated, and the sliding mode control is presented as a robust control technique. The biological interpretation of the results derived from the mathematical model is pointed out, especially of those more closely involved with the implementation, as is the case of sample period, which seems to be very enough with respect to the minimum time needed for sample analysis.

Special Session 2 Innovation in teaching and learning astronomy

On August 17 and 18, 2006, Commission 46 on Astronomy Education and Development held a Special Session at the IAU XXVI General Assembly in Prague. The session, on Innovation in Teaching/Learning Astronomy , was organized around four themes: ( i ) general strategies for effective teaching, ( ii ) connecting astronomy with the public, ( iii ) effective use of instruction and information technology, and ( iv ) practical issues connected with the implementation of the 2003 IAU Resolution that recommended including astronomy in school curricula, assisting schoolteachers in their training and backup, and informing them about available resources. Approximately 40 papers were presented orally; in addition, 60 poster papers were displayed.

NASE Training Courses in Astronomy for Teachers throughout the World.

Network for Astronomy School Education, NASE, is a project that is organizing courses for teachers throughout the entire world. The main objective of the project is to prepare secondary and primary school teachers in astronomy. Students love to know more about astronomy and teachers have the opportunity to observe the sky that every school has above it. Initially, this project is organizing courses for teachers. With the teachers who are highly motivated, working groups are created in order to continue their education in astronomy and sciences, and also to strengthen their relations with NASE and with each other. In this article we give details about the course, the contents, the complementary material for continuity, the structure of the working groups, and the countries in which we were beginning to work in 2010. There is also some information about future plans.

International Contest promoting Astronomy and Mathematics in Spanish and Portuguese speaking countries

Currently our society needs more and more scientists and technicians in order to continue its development. Moreover some areas of our society seem to be less and less interested in scientific issues. It is not possible to value something when we have no knowledge of it. This paper presents an example of a programme carried out in several Science Museums in Spain which puts the average citizen in contact with science.The main objectives of this project are:• to find innovative ideas in order to present science in a more attractive way• to emphasize the international nature of science• to stimulate European contacts• to produce materials for different levels of education• to involve researchers in science communication• to increase the scientific knowledge of citizens• to promote science within the society of participating countries• to reward the professional work of teachers and professors in their teaching activities• to recognize the efforts of journalists specializing in science

A stellar demonstrator

The main purpose of the stellar demonstrator is to help explain the movement of stars. In particular, students have difficulties understanding why, if they are living in the Northern Hemisphere, they may observe starts in the Southern Hemisphere, or why circumpolar stars are not the same in different parts of Europe. Using the demonstrator, these questions and others have a simple answer.

Gravitational lenses in the classroom

It is not common to introduce current astronomy in school lessons. This article presents a set of experiments about gravitational lenses. It is normal to simulate them by means of computers, but it is very simple to simulate similar effects using a drinking glass full of liquid or using only the glass base. These are, of course, cheap and easy materials for school teachers to obtain.