Foreword

In this special issue of "Revista Mexicana de Física S" selected papers from the Fourth International Iberoamerican Conference on Sensors, IBERSENSOR 2004, are published. The papers were rigorously reviewed under the system of anonymous reviewers, under the strict supervision of the Scientific Committee. Each paper was evaluated by at least two referees.

IBERSENSOR 2004 is the fourth edition of the International Iberoamerican Conference on Sensors. The first one, IBERSENSOR 98, was held in Havana, Cuba, in 1998. The second and third conferences (IBERSENSOR 2000 and 2002) took place in Buenos Aires, Argentina, and Lima, Peru, respectively.

IBERSENSOR 2004 was held in Puebla, Mexico, from the 27^th to the 29^th of October, 2004. The official languages were Spanish, Portuguese and English. The objectives of the meeting were:

• To serve as an international forum for the exchange of information on the newest developments in the field of sensors.

• Especially, but not exclusively, to bring together researchers from Iberoamerican countries who work in all sensor disciplines to:

1. Stimulate the collaboration between research groups.

2. Contribute to the development of a scientific and technological framework in Iberoamerican countries.

• To popularize scientific activity in the area of sensors in the midst of Mexican society.

The conferences were organized as guest talks and contributions, which were presented in lectures or in poster sessions.

In order to popularize scientific work in society, a conference devoted to undergraduate students was transmitted using internet media. In this novel approach, a two–day talk on chemical sensors by Dr. Salvador Alegret was transmitted to 12 universities all across the Mexican Republic, and presented to members of three local institutions. The many questions from each institution indicated the success of this talk.

The conference accepted 122 contributions, and 5 plenary guest talks, and all the summaries were published in an abstracts book. Ninety–four participants from 13 countries were officially registered. Three of the invited speakers sent their talks as articles to be published here, and of the 122 contributions accepted, 36 submitted a full paper to be reviewed. After the papers' evaluations, only 75% of them were accepted for publication.

Finally I want to recognize the efforts of all the reviewers that have helped this publication to attain the highest possible level.

Mariano Aceves Mijares

Chairman