Oaxaca, Mexico, was the place chosen by a large international group of scientists to meet and discuss on the recent advances on the understanding of the physical prop- ties of low dimensional systems; one of the most active fields of research in condensed matter in the last years. The International Symposium on the Physics of Low Dim- sions took place in January 16-20, 2000. The group of scientists converging into the historical city of Oaxaca, in the state of the same name, had come from Argentina, Chile, Venezuela, several places in Mexico, Canada, U. S. A. , England, France, Italy, Germany, Russia, and Switzerland. The presentations at the workshop provided sta- of-art reviews of many of the most important problems, currently under study. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Hans Christoph Siegmann, on his sixty-fifth birthday. This Festschrift recognizes the intellectual leadership of Professor Siegmann in the field and as a sincere homage to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Hans Christoph have been deeply impressed by his remarkable analytic mind as well as by his out of range kindness and generosity. Hans Christoph has contributed to the understanding of the difficult and very important problem of the magnetic properties of finite systems: surfaces, thin films, heterostructures.

During August 24-27, 1993, approximately 60 scientists from the Americas, Europe and Japan, gathered in the city of Guanajuato, in the state of Guanajuato, Mexico, at the II Latin American Workshop on Magnetism, Magnetic Materials and their Applications. The group of scientists converging into the beautiful city of Guanajuato had come from Argentina, Chile, Brazil, Venezuela, Cuba, several places in Mexico, U. S. A. , Japan, Spain, France, Italy, Germany, Austria, Switzerland, and Denmark. The event attested to the success of the previous Workshop on Magnetism, Magnetic Materials and their Applications, held in Havana, Cuba, in 1991, as well as to the interest, level of activity and quality of the work being carried out in Latin America in the area of magnetism and magnetic materials. Equally important to everyone present was the fact that we had come to honor a friend, Professor L. M. Falicov, on his sixtieth birthday. The choice of a Latin American Workshop on magnetism as a Festschrift for Leo Falicov was, in our opinion, quite appropriate not only because of Leo's strong ties to Latin America, but also because of his superb contributions to science, and in particular, to magnetism. Professor Falicov was born in Buenos Aires, Argentina, where he spent a good part of his formative years.

This volume contains the papers presented at the International Workshop on the Cur rent Problems in Condensed Matter: Theory and Experiment, held at Cocoyoc, More los, Mexico, during January 5-9, 1997. The participants had come from Argentina, Austria, Chile, England, France, Germany, Italy, Japan, Mexico, Switzerland, and the USA. The presentations at the Workshop provided state-of-art reviews of many of the most important problems, currently under study, in condensed matter. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Karl Heinz Bennemann, on his sixty-fifth birthday. This Festschrift is just a small measure of recognition of the intellectualleadership of Professor Bennemann in the field and equally important, as a sincere tribute to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Karl have been deeply touched by Karl's inquisitive scientific mind as well as by bis kindness and generosity."

High Temperature Materials.- The Frontiers of High Temperature Structural Materials.- Magnetic Properties.- Effect of Long Range Ordering on the Magnetic and Electronic Properties of Some Transition Metal Based Alloys.- Ferromagnetic Behavior pf Pd- and Pt-Based Alloys.- Statistical Mechanics and Thermodynamics.- Monte Carlo Simulation of Order-Disorder Phenomena in Binary Alloys.- Compatibility of Lattice Stabilities Derived by Thermochemical and First Principles.- Order-Disorder Kinetics Studied by the Path Probability Method.- Electronic Theories.- Modeling of Invar Properties from Electronic Structure Calculations.- Angularly Dependent Many-Body Potentials Within Tight Binding Huckel Theory.- Structure and Thermodynamics of SixGe1-x Alloys from Computational Alchemy.- First Principle Calculation of Phase Diagrams.- On the Causes of Compositional Order in the NiPt Alloys.- Low Dimensional Systems.- Ultrathin Films of Transition Metals and Compounds: Electronic Structure, Growth and Chemical Order.- Alloy Surface Behavior: Experimental Methods and Results.- Structural Phase Transformations in Alloys: An Electron Microscopy Study.- Thermodynamics of Surfaces and Interphases.- Spatial Ordering in Bimetallic Nanostructures.- Summary.- Summary Thoughts.

Advances in Superalloys and High Temperature Intermetallics (J.K. Tien et al.). Influence of the Superplastic Metals on the Future of the Metal Forming Industry (G. Torres-Villasenor). Advanced Aerospace Materials (F.H. Froes et al.). Microalloyed Steels (L. Martinez). Future Ferrous Technologies (H.W. Paxton). Advanced High Temperature Corrosion Sciences (N. Birks et al.). Engineering Materials (V.M. Castano et al.). Advanced Textile Structural Composites (F.K. Ko). Cracking and Fatigue in FiberReinforced Metal and Ceramic Matrix Composites (A.G. Evans, F.W. Zok). Metallurgy of Permanent Magnet Alloys (L. Rabenberg). Electron Tunneling in Superconductors Ba-K-Bi-O (R. Escudero). Vapor Deposition Processing (S. Purushothaman et al.). Thin Films for Photovoltaic Applications (R. Asomoza et al.). Optical Properties of New Materials (R.G. Barrera). 6 additional articles. Index.

This volume contains the papers presented at the International Workshop on the Cur rent Problems in Condensed Matter: Theory and Experiment, held at Cocoyoc, More los, Mexico, during January 5-9, 1997. The participants had come from Argentina, Austria, Chile, England, France, Germany, Italy, Japan, Mexico, Switzerland, and the USA. The presentations at the Workshop provided state-of-art reviews of many of the most important problems, currently under study, in condensed matter. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Karl Heinz Bennemann, on his sixty-fifth birthday. This Festschrift is just a small measure of recognition of the intellectualleadership of Professor Bennemann in the field and equally important, as a sincere tribute to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Karl have been deeply touched by Karl's inquisitive scientific mind as well as by bis kindness and generosity."

This vohune contains the papers presented at the Adriatico Research Conference on Structural and Phase Stability of Alloys held in Trieste, Italy, in May 1991, under the auspices of the International Centre for Theoretical Physics. The conference brought together participants with a variety of interests in theoretical and experimental aspects of alloys from Argentina, Belgium, Bulgaria, Czechslovakia, France, Germany, Italy, Japan, Mexico, People's Republic of Congo, Portugal, Switzerland, United Kingdom, United States, U. S. S. R., and Venezuela. The conference was purposely designed to succinctly cover experimental and the oretical aspects of magnetic and non-magnetic alloys, surfaces, thin films and nanos tructures. The Conference opened with an overview of a select class of advanced structural materials, with a potential in engineering applications, for which the con ventional "physics" approach, both theoretical and experimental, should have a sig nificant impact. A number of papers were dedicated to the use of phenomenological approaches for the description of thermodynamic bulk and surface properties. It was clear from these presentations that the phenomenological models and simulations in alloy theory have reached a high degree of sophistication. Although with somewhat limited predictive powers, the phenomenological models provide a valuable tool for the understanding of a variety of subtle phenomena such as short-range order, phase stability, kinetics and the thermodynamics of surfaces and antiphase boundaries, to name a few."

This volume contains the papers presented at the First Mexico-U.S.A. Symposium on Materials Sciences and Engineering held in Ixtapa, Guerrero, Mexico, during Septem ber 24-27, 1991. The conference was conceived with the primary objective of increas ing the close ties between scientists and engineers in both Mexico and the U.S. with an interest in materials. The conference itself would have not taken place without the drive, determination and technical knowledge of John K. Tien of the University of Texas at Austin and of Francisco Mejia Lira of the Universidad de San Luis Potosi. This book is dedicated to their memory. The event brought together materials scientists and engineers with interests in a broad range of subjects in the processing, characterization and properties of advanced materials. Several papers were dedicated to structural materials ranging from ferrous alloys to intemetallics, ceramics and composites. The presentation covered properties, processing, and factors that control their use, such as fatigue and corrosion. Other materials and properties were also explored by U.S. and Mexican participants. Sev eral papers dealt with the characterization and properties of magnetics, optical and superconductor materials, nanostructured materials, as well as with computational and theoretical aspects likely to impact future materials research and development."

During August 24-27, 1993, approximately 60 scientists from the Americas, Europe and Japan, gathered in the city of Guanajuato, in the state of Guanajuato, Mexico, at the II Latin American Workshop on Magnetism, Magnetic Materials and their Applications. The group of scientists converging into the beautiful city of Guanajuato had come from Argentina, Chile, Brazil, Venezuela, Cuba, several places in Mexico, U. S. A. , Japan, Spain, France, Italy, Germany, Austria, Switzerland, and Denmark. The event attested to the success of the previous Workshop on Magnetism, Magnetic Materials and their Applications, held in Havana, Cuba, in 1991, as well as to the interest, level of activity and quality of the work being carried out in Latin America in the area of magnetism and magnetic materials. Equally important to everyone present was the fact that we had come to honor a friend, Professor L. M. Falicov, on his sixtieth birthday. The choice of a Latin American Workshop on magnetism as a Festschrift for Leo Falicov was, in our opinion, quite appropriate not only because of Leo's strong ties to Latin America, but also because of his superb contributions to science, and in particular, to magnetism. Professor Falicov was born in Buenos Aires, Argentina, where he spent a good part of his formative years.

Oaxaca, Mexico, was the place chosen by a large international group of scientists to meet and discuss on the recent advances on the understanding of the physical prop- ties of low dimensional systems; one of the most active fields of research in condensed matter in the last years. The International Symposium on the Physics of Low Dim- sions took place in January 16-20, 2000. The group of scientists converging into the historical city of Oaxaca, in the state of the same name, had come from Argentina, Chile, Venezuela, several places in Mexico, Canada, U. S. A. , England, France, Italy, Germany, Russia, and Switzerland. The presentations at the workshop provided sta- of-art reviews of many of the most important problems, currently under study. Equally important to all the participants in the workshop was the fact that we had come to honor a friend, Hans Christoph Siegmann, on his sixty-fifth birthday. This Festschrift recognizes the intellectual leadership of Professor Siegmann in the field and as a sincere homage to his qualities as an exceptional friend, college and mentor. Those who have had the privilege to work closely with Hans Christoph have been deeply impressed by his remarkable analytic mind as well as by his out of range kindness and generosity. Hans Christoph has contributed to the understanding of the difficult and very important problem of the magnetic properties of finite systems: surfaces, thin films, heterostructures.

The papers in this book represent the proceedings for the International Conference on Oxygen Disorder Effects in High~Tc Superconductors, held April 18-21, 1989 at the International Centre for Theoretical Physics, Trieste, Italy. It was recognized very early in the field of ceramic superconductors that oxygen plays a crucial role as far as the physical properties of these ma terials are concerned. The preparation requires special heating and cooling cycles which allow proper uptake of oxygen, relationships were found between the oxygen concentration and the superconducting transition temperature in many of the compounds and quite recently it was recognized that many (if not all) of the compounds present oxygen ordering in the intercalating planes. Moreover, it seems that the presence of superconductivity is strongly correlated with the presence of orthorhombic phases although several groups have also claimed the presence of superconductivity in tetragonal phases. Whether oxygen ordering plays or not a crucial role for the superconductivity remains to be seen. However it is clear that the ordering of oxygens and their thermodynamic properties is an interesting subject on its own right. All these reasons led us to organize a Conference on Oxygen Disorder Effects in High-Tc Superconductors in attempt to identify unsolved problems and to have an open discussion of the presently known facts.

This volume is a compilation of papers presented at the International Workshop on the Theory and Applications of the Cluster Variation and Path Probability Methods, held in the city of San Juan, Teotihuacan, Mexico, during June 18-22, 1995. The presentations at the workshop provided a state of the art review of the fundamental aspects of the CVM and PPM and their application to a wide range of problems in statistical mechanics and alloy theory. The volume begins with several articles dealing with the study of the kinetics of ordering in Ising sytems and alloys using the PPM and other classical techniques. These articles are followed by the contribution of Professor Masuo Suzuki on the Coherent Anomaly Method which has added a new dimension to mean field theory, and the CVM in particular, in the study of critical phenomena. The remaining of the volume is dedicated to fundamental aspects and specific applications of the CVM in a wide range of subjects ranging from bulk and surface studies to new areas of inquiry such as the problem of image reconstruction. Since the inception by Prof. Ryoichi Kikuchi of the CVM in 1950 and of the PPM in 1966, the latter after a gestation period of approximately six years, the tech niques have found wide acceptance in the physics and materials science communities. Both methods are properly regarded as seminal contributions to equilibrium and non equilibrium statistical mechanics."