In 1938 an event occurred that changed my life, as well as that of many other Tuxpenos: Professor Manuel C Tello came to Tuxpan from Jalapa and established the secondary and high school that today bears his name, and which since then has depended on the Universidad Veracruzana. I was from the fourth generation of students, and received a solid preparation there, thanks to the commitment and great academic and human quality of teacher Tello and the other professors, most of whom were professionals who pursued their careers in Tuxpan and dedicated a good part of their time to teaching.

... excelled in studies and sports, mainly volleyball; he also practiced drawing and painting. Already then his inclination for graphic arts was noticeable, which would later culminate in scientific journals. In high school he founded and directed a publication called 'Juventud'; in it he wrote, drew and also got into the printing press to collaborate manually: he himself confesses a certain addiction to ink.

In a recent publication['Self-adjointness of a certain type of vectorial boundary value problems' (Spanish)] a matrix type of boundary value problem was introduced in order to simplify the description of nuclear reactions. It appeared that this type of boundary value problem could find applications in other branches of mathematical physics, and the purpose of the present note is to illustrate them.

When we deal with vibrations of continuous media, with problems of heat flow etc., we usually describe the state of the system in terms of a single function which depends on position as well as on the time. As an example, we may mention the lateral displacement of a vibrating string, or the temperature function in case of problems of heat flow.

In many problems of vibration and heat conduction, of which examples will be given below, the description of the state by a single function leads to boundary value problems of great difficulty. It is possible though, in some cases, to divide the continuous medium into several regions, and with each region we can associate a function describing its state. These functions can be grouped together in the form of a column matrix or vector, which will then represent the state of the whole system. The mathematical problem we encounter then, is a matrix boundary value problem, which is, in general, much simpler than the one we would have to deal with in the usual formulation.

In the present note, we shall discuss two examples of matrix boundary value problems. The first one describing the flow of heat in a cross, illustrates the case where the interactions between the different regions appear through boundary conditions. The second one, dealing with the vibration of systems of plates with intermediate elastic media, illustrates the case where the interactions take place through the equations of motion. We shall obtain the eigenvalues and eigenmatrix functions corresponding to this type of problems, and with the help of them, give a formal solution for any initial conditions.

The authors are thankful to engineer R Monges López, Director of the Instituto de Geofísica, for the encouragement he has given to the present research. This work was supported, in part, by the Instituto Nacional de la Investigación Científica.

In the first part of this report we find an exact solution for the problem of steady wave propagation in an isotropic, elastic circular bar of infinite length, free of stress on its lateral surface and loaded by a harmonic body force, parallel to its axis, whose amplitude is a Dirac delta function. The solution of this problem gives at the same time the solution for a semi-infinite bar with a special prescribed load on its boundary plane.

Upon my return to Mexico, after the initial construction of the brand new Ciudad Universitaria had been completed, the Institute of Geophysics was established on floors 3, 4 and 5 of the then Tower of Sciences, and now Tower II of Humanities. Upon returning, the engineer Monges López invited me to help him with the academic-administrative task.

A few days later I received a personal invitation from Professor Rossby, and with the consent of engineer Ricardo Monges López I left for Sweden in October 1954 for a postdoctoral stay that would decide my entry into research in the area of atmospheric science. It was the time when electronic computers were becoming available for research, which made it possible to try to solve fluid dynamics equations in a practical way, and the era of numerical models for climate prediction began, which was a magnificent opportunity for an applied mathematician. My ticket to Sweden was paid for by the Ministry of Foreign Affairs, at the request of the then coordinator of Scientific Research, Dr Alberto Barajas.

A method to obtain a series solution for the barotropic non-divergent, vorticity equation is given and is applied to the case of a vortex. A formula that gives the development of a symmetrical vortex as a function of radius, maximum velocity and latitude is obtained. A numerical example is worked out. The convergence of the series solution for the general case is discussed and shown to depend on the scale of motion to be forecast and conclusions are drawn regarding time-steps used in a forecast and the smoothing of the initial map. The possibility of improving a forecast and reducing the number of time-steps used in it by the application of this series solution, follows as a general conclusion. Finally, a theorem that gives the scaling of the variables in an experimental model of a barotropic flow is obtained.

The author is a member of the Instituto de Geofisica, Universidad Nacional de Mexico and of the Instituto Nacional de la Investigación Cientifíca, Mexico City. He undertook the investigation reported in this paper when he was on leave in Stockholm.

The man-made moons which will be launched into space during the International Geophysical Year will be visible from Mexico City with ordinary binoculars. ... the public will be duly informed when the satellites are launched and the course they will take. Scientific observations of the satellites will be made from the Tonantzintla Observatory in Puebla, which operates under the auspices of the National University of Mexico. ... pictures of recent eruptions on the surface of the sun are being taken and sent to Germany for interpretation.

By considering the conservation of energy and the balance of radiation in the troposphere, in the cloud layer, and in the surface of the earth, we obtain a system of six equations containing six unknowns. The variables are the temperatures and the excesses of radiation in the troposphere, in the cloud layer, and in the surface of the earth. The equations contain as parameters the insolation, the cloudiness, the heat given off by the oceans and the continents to the atmosphere, and the initial temperature distributions. The model contains only meridional turbulent transport in the troposphere. Computations for both hemispheres and for the four seasons, as well as for the annual case, are carried out, obtaining a remarkable agreement with observations.

After five years as a researcher at that centre in Washington, D.C., Dr Pablo González Casanova, then rector of UNAM, called me on the phone to inform me that several researchers were proposing me as a candidate for a second term as director of the Institute of Geophysics. After consulting with the family, I accepted the proposal and moved to Mexico, following the recommendations of the rector. The Governing Board unanimously appointed me director and I re-joined the UNAM, with my old position as top-ranking researcher.

Adem's numerical-thermodynamical model has been used to simulate an ice-free Arctic. Computed sea water temperatures are similar to observed high latitude ice-free parts.
...
The fourth speaker was Julian Adem of the Instituto de Geofisica who presented a number of results of numerical thermodynamic experiments on climate changes. The predictions obtained from his thermodynamic model were said to agree well with the observed SSTA pattern observed in the eastern North Pacific ocean. Dr. Adem also showed a set of experiment results by changing different parameters in the model.
...
David M Shaw of the University of Rhode Island presented the final paper coauthored by William L Donn: 'Application of Adem's Model to Paleozoic and Cenozoic Climates'. They have applied Adem's model to various stages of continental drift and have determined that there would be no ice at the pole if it were in a large, open ocean. Since, however, the Arctic ice at present is only 3 m thick, this would change the water balance of the globe. It appears that the depth of the mixed layer in the ocean is more critical than cloud cover and other parameters. He pointed out that 250 million years ago, the continents were almost all in the Southern Hemisphere with presumably an ice-free Arctic until at least one hundred million years B. P. By 25 million B. P. the Arctic had probably iced up.

A new quarterly journal devoted to the publication of original research papers on the atmospheric sciences, in English or Spanish, is scheduled to appear beginning in 1988. The journal will have a broad scope, including a variety of topics, ranging from theoretical and applied studies to interdisciplinary studies. The editorial staff consists of Julián Adem, editor; Carlos Gay, associate editor; and Thelma del Cid, technical editor.

Julián Adem is a true gentleman, simple and methodical, an aristocrat. All his life he has looked good: lean, healthy, and vigorous. He takes a daily walk through the University City, which seems to him the most beautiful campus in the world, frequently swimming at his house in Tepoztlán, Morelos. Although he is modest and reserved, he considers that his daily presence at the Centre for Atmospheric Sciences is motivating and paradigmatic. He is frank, approachable, and courteous to everyone: academics, students, and administrators; and for everything from a greeting in the hallway to a technical discussion in his cubicle.

He is loyal to science, UNAM and Mexico. Surely in engineering he would have become rich and in a foreign institution he would have had better income than in our University. In economic and political terms, he says that you have to play it with the institution and the country. He is patriotic and has the university at heart. He recommends honesty as the motto for everything, particularly scientific research. He advises choosing collaborators more for their high moral level than for their high academic performance.