The first years of the 90s have witnessed thorough political and economic changes in northern Europe. The long period of strong political separation between east and west and the less strong economic separation between the northern and southern sides of the Baltic Sea seemed to be replaced by far-reaching integration. There is no doubt that further integration will have additional impacts on the regional patterns in northern Europe. The amplitude and composition of these changes are difficult to project. In this volume a number of scholars in regional science and related disciplines (geography, economics, environmental and political sciences, planning) have brought together important material on the current processes that reshapes northern Europe. Visions andstrategies on local, national and supranational levels are penetrated in depth. A "mosaic" vision of the regional development pattern emerges highlighting the importance of cooperative and competitive strategies affecting the local conditions of European regions.

The message of sunspots from the interior of the Sun to the Earth's climate When Galileo was summoned before the Inquisition on April 12, 1633, the main accusations laid against him concerned the doubts he expressed about Aristotle's theory of the universe. Aristotle's idea was that the Earth was the centre of the cosmos and that all of the stars, including the Sun, turned around it. Moreover, for Aristotle and the world of the Inquisitors, the Sun was a perfect celestial body. Now, Galileo had discovered spots on the Sun. These spots were seen as imperfections, and not just surface markings, but coming from within the Sun. Worse yet, they revolved around the Sun. All this supported the newfangled theory of Copernicus, and undermined a system of thought that had reigned supreme for centuries. Man of science that he was, and a prudent Catholic too, Galileo strived all his life to prove that Copernicus' astronomical concept was compatible with the word of the Bible. He proposed that there were not two truths but a single divine truth. It was just expressed in two different languages : there was the language of the common people, with its imprecision and inconsistencies, but intuitively understandable by everyone; and then there was the precise language of science with its strict regard for observation, which only a chosen few can grasp [L. Geymonat. 1992].

Major structural features are used in this study to reconstruct the links which existed between North America, Europe and Africa before the opening of the North Atlantic Ocean. The synthesis of geophysical and geochemical data as well as geological observations allows the recognition of the original geometry of the Grenvillian, Cadomian, Caledonian, Ligerian-Acadian and Hercynian foldbelts and the identification of ancient plate sutures. The reader will find a wealth of information based not only on the English but also on the French and Spanish literature, thus opening less known results to the international community.

We all know that networks are fundamental prerequisites for prosperity and production. Transportation and communication are indispensible to society, they are the elements which bind all economic systems together. Without networks and communica tion all social and economic life will be reduced to isolated phenomena. Therefore, transportation can't be assessed in the same way as other services. A smoothly functioning system of communications is also a prerequistite for social and economic integration between separate geographical regions. The modernization of the infrastructure is therefore an urgent task and a precondition for carrying out the whole of Europe's ambitious political, economic and social agenda. Since the need for communication and transportation does not know any national borders, the functioning of the networks needs to be adopted to this new economic and political geography. Congestions of cities, highways, railroads, airways and tele communications must be tackled, if precious working, commuting and leisure time is not to be wasted and heavy burdens on the environment avoided. European traffic, is for example, expected to double within the next twenty years. In certain transport modes the growth is expected to be even faster - air passenger transport doubled in 10 years and goods transport on roads doubled in 15 years."

Europe's space is in a flux. Earlier cores and peripheries in Europe are experiencing a profound transformation. The driving forces include, amongst others, Western European economic and political integration, and Eastern European transition. We are also witnessing fundamental technological and organisational restructuring of industrial systems. Information technology and telecommunications are rapidly altering the requisites for comparative advantage. Peripherality is being determined more by access to networks than by geographical location. Economies of scale can be attained in distributed networks of production with good access to markets as well as in large agglomerations. Clearly, these changes also call for new perspectives in regional analysis. This book derives its impetus from an Advanced Summer institute in Regional Science which was arranged in Joensuu, Finland, in 1993 under the auspices of the European Regional Science Association. Some of the papers, which were discussed at the institute, were thoroughly revised for the present purpose. In addition, chapters on specific topics were specially written for the volume. In most contributions, the focus is on the Nordic countries and their internal peripheries. They form a particularly interesting case in assessing prospects for the multi-faceted centre-periphery confrontation in Europe.

Clay minerals form in a wide variety of crustal environments, e.g. in soil profiles, in sediments at the surface and in deeply buried sedimentary deposits, and under regional, contact and hydrothermal metamorphism conditions.
The book provides information about the dynamics of isotope systems in clays and helps us to understand the physical and chemical parameters in the transfer of masses within the crustal domain. Written for graduate students taking courses in sedimentary geochemistry, clay mineralogy, and soil mineralogy, the book will also appeal to scientists carrying out research on clay genesis and mass transfer in crustal environments.

This volume is the result of an international collaboration, which started with a conference at Smadalaro Gfrrd in Sweden. The workshop was supported by the National Science Foundation of the USA (INT-9215114) and by the Swedish National Road Administration, the Swedish Council for Building Research, the Swedish Transport and Communications Research Board and the Swedish Council for Planning and Coordination of Research. This support is gratefully acknow ledged. The collaboration started as a bilateral u.S.-Swedish endeavour but was soon widened to other scholars in Europe, Asia, Australia and South-America. Network Infrastructure and the Urban Environment is a policy area of growing importance. Sustainable cities and sustainable transport systems are necessary for attaining a sustainable development. The research and policy field, represented in this volume, comprises a number of challenging contrasts: - the contrast between infrastructure investments, mobility and environmental sustainability; - the contrast between policy contexts, modelling traditions and available decision support systems in various parts of the world; - the contrast between available best practice methods and the majority of models applied in planning; the contrast between static models of cross-sectionary equilibria and dynamic models of disequilibrium adjustments; and the contrast between state-of-the-art operationalland-use/transport models and new demands for land-use/transportlenvironment models due to changing policy contexts. Bridging some of these gaps constitutes important research tasks, that are discussed in the twenty-two chapters of this book. A number of emerging research directions are identified in the introduction and summary chapter."

Gravity models describe, and hence help predict, spatial flows of commuters, air-travelers, migrants, commodities and even messages. They are one of the oldest and most widely used of all social science models. This book presents an up-to-date, consistent and unified approach to the theory, methods and application of the gravity model - which spans from the axiomatic foundations of such models all the way to practical hints for their use. "I have found no better general method for use in applied research dealing with spatial interaction... It is against this background that the present book by Sen and Smith is most welcomed." "Walter Isard"

The Arctic troposphere (0 to ca. 8 km) plays an important role in environmental concerns for global change. It is a unique chemical reactor influenced by human activity and the Arctic ocean. It is surrounded by industrialized continents that in winter contribute gaseous and particulate pollution (Arctic haze). It is underlain by the flat Arctic ocean from which it is separated by a crack-ridden ice membrane 3 to 4 m thick. Ocean to atmosphere exchange of heat, water vapor and marine biogenic gases influence the composition of the reactor. From September 21 to December 21 to March 21, the region north of the Arctic circle goes from a completely sunlit situation to a completely dark one and then back to light. At the same time the lower troposphere is stably stratified. This hinders vertical mixing. During this light period, surface temperature reaches as low as -40 DegreesC. In this environment, chemical reactions involving sunlight are generally much slower than further south. Thus, the abundance of photochemically reactive compounds in the atmosphere can be high prior to polar sunrise. Between complete dark in February and complete light in April, a number of chemical changes in the lower troposphere take place.

Seasonal Snowpacks examines the processes which control the chemistry of seasonal snowcover and provides detailed information on the biogeographical distribution of snow (e.g. urban, alpine snowpacks), snow composition (e.g. micropollutants, stable isotopes) or the physical and biological processes which influence the chemical changes in snow (e.g. wind, microbiological activity). The fluxes of chemicals at the snow-atmosphere and snow-soil interfaces are examined, as are processes which modify composition within the snowcover. It is the first book in which the reader will find a comprehensive overview of the theoretical concepts, latest measurement techniques, process-oriented research methods, and models of studies in snow chemistry. The linkages between snow chemistry, atmospheric chemistry and hydrology will make this book of use to both research workers and students in the physical and biological sciences and to natural resource management personnel.

Is our world more dynamic than it used to be in the past? Have phenomena in the social science field become unpredictable? Are chaotic events nowadays occurring more frequently than in the past? Such questions are often raised in popular debates on nonlinear evolution and self-organizing systems. At the same time, many scientists are also raising various intruiging methodological issues. Is it possible to separate deterministic chaos from random disturbances if their trajectories are (almost) similar? Is prediction still possible in a world of chaos (Poincare)? Is it possible to distinguish specification errors from measurement errors in a nonlinear dynamic model? Is evolution a random process? The list of such questions can easily be extended with dozens of others. But despite the myriad of questions on problems of nonlinear evolution, one common trait is evident: in both the natural and the social sciences we are still groping in the dark in areas which are par excellence promising hunting grounds for exploratory and exploratory research, viz. structural grounds in an uncertain nonlinear world. The present book aims at offering a collection of refreshing contributions to the above research issues by focusing attention, in particular on nonlinear dynamic evolution in space at the Netherlands Institute for Advanced Study (NIAS) in Wassenaar, the Netherlands. The Institute has to be thanked for its hospitality and support, reflected inter alia in a workshop at which several of the papers included in this book were discussed.

Regional science, as an integrating discipline for many scientific analyses concerning the element of space, has a remarkable record of achievements in both breadth and depth. The great many scientific journals in this field and the large number of regional science books mirror the appeal of this discipline, in both the developed and the developing world. The scientific organization in this area, the Regional Science Association International, is organizing a world conference every four years. The 1989 Regional Science World Conference was held in an interesting setting, viz. kibbutz Ramat Rachel on the outskirts of Jerusalem. The organization of this meeting was undertaken by the Israeli Section of the Regional Science Association, under the supervision of Professor Rafi Bar-EI (Development Study Center, Rehovoth). The meeting turned out to be a great success and provided an extremely interesting cross-section of new developments in the area of regional science. It was decided afterward to publish a set of representative papers from this meeting in one volume. The present book brings together these papers, which were duly selected after a careful screening and refereeing process. The editors wish to thank all referees for their willingness to assist them in the task of producing this volume. Many thanks also go to Rita Hittema for her skillful copy-editing and word processing of the manuscript."

"Heavy Metals: Problems and Solutions" is divided into three sections dealing with basic geochemical processes, remediation and case studies. The basic geochemical processes are discussed with respect to mobility in the environment and impact as well as methods to derive guidelines for heavy metals. Remediation focuses on currently available methods to treat contaminated sediments and soils. In addition, it considers the concept of geochemical engineering for remediation of large areas contaminated by metals. A number of case studies of polluted sediments and soils and their environmental impact highlight the principles discussed in the first two sections.

Compared with forces occurring in soil mechanics problems in civil engineering, the forces that are applied to soil in farming operations generally have a short duration, less than a few seconds, a small loaded area, no more than a few square decimeters, and small intensities, 10 bar being a high value. On the other hand, soil properties vary widely between those of a weak mud and a stone-like dry soil. Tillage and related applications of force to soil are practiced worldwide in farming. Tillage operations are performed on one hectare of land for every three human beings. This means that for the food production for each individual daily, something like one cubic meter of soil is stirred, or about 20 times his body weight. Theoretical knowledge of this most common human activity, which largely determines the surface shape of the fertile part of the earth, is still very limited. In this book the authors have tried to give an outline of the present state of the art. One of the starting points was a course in soil dynamics taught by the authors at the Agricultural University at Wageningen, The Netherlands. We hope to reach interested readers who have no more theoretical knowledge than high school level, as well as readers who want to go beyond the level of a third year university student. For the chapter on wheels and tires we received substantial support from F. G. J. Tijink of the Tillage Laboratory at Wageningen.

Central and Eastern European Countries are undergoing a difficult transition process with consequences for spatial development. Europe needs a more bal anced, polycentric system of cities, a new urban-rural relationship, parity of ac cess to infrastructure and knowledge as well as prudent management and devel opment of the natural and cultural heritage. Dealing with these complex challenges and the need for sustainable develop ment politicians requires qualified advice from experts. To this end, the German Ministry for Regional Planning, Construction and Urban Development initiated the Network of Spatial Research Institutes in Central and Eastern Europe (CEE Net) in 1992. Exchange of knowledge and an open dialogue at all levels are pre conditions for the cooperative development of visions and strategies serving spa tial development in Europe. The annual conferences of the network have been a first steps towards closer cooperation. The high interest shown in these confer ences by academics and government representatives and the fact that several re search projects have already crystallised out of the debates they engendered indi cate that the network is meeting a need for exchange and cooperation. Decisions on spatial development do not stop at national borders and the dis cussion on spatial development in any European region has therefore to take the European context into consideration. A special advantage of this publication is that, as well as focusing on spatial development and research in CEE regions, it also discusses Central and Eastern Europe in a European context."

will probably be clarified by the continued cooperative efforts of scientists such as those in the group that met in Berlin last September. The staff of Dahlem Konferenzen is responsible for making the meeting of this group memorably pleasant and pleasantly mem- orable. Dr. Bernhard's gifts of charm, organizational skill, and administrative toughness assured that the conference was run elegantly, smoothly, and decisively, even down to the choice of editors for this volume. Marie Cervantes-Waldmann performed minor miracles extracting manuscripts gently but persistently from the authors and in turning the typescripts into a book. The other staff members of Dahlem Konferenzen were unfailingly helpful even under trying circumstances. They will be well rememberedbyall who were fortunate enough to be asked to Berlin for the first week in September, 1980. Mineral Deposits and the Evolution of the Biosphere, eds. H. D. Holland and M. Schidlowski, pp. 5-30. Dahlem Konferenzen, 1982. Berl in, Heidelberg, New York: Springer-Verlag. Microbial Processes in the Sulfur Cycle Through Time H. G. TrUper Institut f. Microbiologie, Rheinische Friedrich-Wilhelms-Universitat, 5300 Bonn 1, F. R. Germany Abstract. Two microbial processes are involved in the sulfur cycle of the earth's biosphere: anoxic dissimilatory sulfur oxidation by phototrophic bacteria and dissimilatory sulfate reduction by sulfate-reducing bacteria. In the presence of oxygen at chemoclines and redoxclines dissimilatory sulfur oxidation by chemolithotrophic bacteria (Thiobacillus, Beg- giatoa, and others) occurs. In addition, dissimilatory sulfur reducing bacteria participate in the sulfur cycle.

1. 1 A Brief History of U. S. Commercial Aviation Regulation and Deregulation The U. S. commercial aviation industry was regulated by the government for a period of 40 years, beginning in 1938 with. the passing of the Federal Aviation Act, and ending in October 1978 when President Carter signed into law the Airline Deregulation Act (ADA). There were 16 airlines in existence when the Federal Aviation Act was passed in 1938 (the so-called 'trunk lines'). The Act established the Civil Aeronautics Authority (CAA) as the industry's regulatory body. The Act was passed principally because it was felt that the free market, if allowed to continue unregulated for much longer, would put many of these firms into bankruptcy. It is possible therefore to view the CAA of 1938 (re-organized into the Civil Aeronautics Board (CAB) in 1940) as a response to a potential market failure at the time. In the 1930s, few air traffic markets could have efficiently"supported more than one airline operating in the market [Panzar (1980)]. Competition among the carriers was cut-throat, and it was felt that the near bankruptcy of the airlines in the period was caused principally by the competitive bidding system used by the Post Office in allotting airmail subsidies [Keeler (1972), Caves (1962)].

In keeping with the spirit of an Advanced Series in the Agricultural Sciences, we have attempted to address herein most of the current research areas being used to characterize, describe and manage salt-affected soils. Because of a certain amount of personal bias inherent in our individual viewpoints and backgrounds, some areas have been accorded more emphasis than others. It has been our goal, however, to provide either detail about, or at least a recent reference to, each major area of current soil salinity research. This information, coupled with what we hope to be a rather logical progression from descriptive material on equilibrium or near-equilibrium soil chemistry, through transport processes, to eventual management practices including some elementary economic decisions, should enable the reader to bridge the gap from introductory soil chemistry or soil physics texts to the basic literature of this area. The text will be perceived by the astute reader as somewhat uneven in its treatment of respective sections. We feel that this is to a certain extent appropriate, for it thus portrays the unevenness of progress to date in the corresponding areas of research. The management of saline and sodic soils remains largely an empirical semi-science or even art, whereas transport phenomena are normally dealt with in a much more theoretical (and also a much more highly mathematical) vein. Equilibrium soil chemistry has historically occupied an intermediate position with respect to its mix of empiricism and theoretical rigor.

The promising new directions for research and applications described here include alternative model specifications, estimators and tests for regression models and new perspectives on dealing with spatial effects in models with limited dependent variables and space-time data.

Climate is the most important component of the Earth's environment and climatic fluctuations have a strong impact on water supplies, vegetation, energy use etc. Thus our understanding of the climatic system is of utmost importance. Leading experts in the field of climate modelling and paleoclimatology present the most recent methods for reconstructing past climatic variations and for modelling the climatic system and its evolution. The first of three parts is devoted to the climatic system and the physical basis for its modelling; the second summarizes the evolution of the global atmosphere, the ocean, the continents, the biosphere, and the ice sheets during recent climatic cycles; the last part focusses on the understanding of past and future climatic changes.

The surface features of the Earth are commonly split into two categories, the first of which comprises those features that are due to processes occurring inside the solid Earth (endogenic features) and the second those that are due to processes occurring outside the solid Earth (exogenic features). Specifically, the endogenic features are treated in the science of geodynamics, the exogenic features in the science of geomorphology. I have treated the theoretical aspects of the endogenic features in my Principles of Geodynamics, and it is my aim to supplement my earlier book with a discussion of the theory of the exogenic features, the taxonomy of the latter having been discussed in my Systematic Geomorphology. It is my hope that the three books will together pre sent a reasonably coherent, if necessarily incomplete, account of theoretical geology. Contrary to endogenic phenomena, exogenic processes can often be directly observed as they occur: the action of a river, the develop ment of a slope, and the evolution of a shore platform are all suffi ciently rapid so that they can be seen as they take place. This has the result that in geomorphology one is generally on much less specula tive ground regarding the mechanics of the processes at work than one is in geodynamics.

The importance of irrigation in the world's agriculture is rapidly increasing. Although it is practised on a large scale mainly in arid and semi-arid zones, supplementary irrigation is becoming popular in semi-humid regions as well. The record of irrigation speaks for itself in terms of increased crop production. However, the question remains as to how permanent the achievement may be. Judging from history, it seems that irrigation eventually failed in many regions because the knowledge and technology available to society at the time were incapable of coping with the problems created. Undoubtedly soil salinity is the most prevalent and widespread problem limiting crop productivity in irrigated agriculture. It has, therefore, attracted the attention of the scientific community since the advent of modern agronomic research. Through the past six to seven decades a considerable body of information has been accumulated, which has promoted the understanding of the principles involved and helped to develop the technology for coping with the problems. Our present knowledge, if judiciously applied, is adequate for coping with many of the salinity problems resulting from mismanagement of irrigation and drainage. But for this knowledge to be used, it has to be generally known and understood and be re-examined from time to time.

As European countries pursue a common effort towards establishing a European Union, various isolated -and consequently disadvantaged -regions are likely to face increasing competitive pressures due to their peripheral location. To assist such areas, regional, national and supranational bodies put much effort into developing transport and communication networks and linkages in order to ensure that such less favoured areas are better integrated in the broader European social and economic development process. This book addresses the issue of lagging development in various -mainly central and southern - European regions which are in a disadvantageous position as a result of their isolated 10cation...The persisting problems of social and economic development in several European Union areas (e.g. islands, mountains, border areas) has turned the attention of policy-makers to "the critical importance of transport and (tele)communication linkages. The purpose of the book is to bring into perspective the role of transport and communications in regional policy for peripheral areas. This subject is currently of high priority, since the European Union through the Structural Funds interventions (i.e. the Community Support Frameworks) and the new Cohesion Fund relies heavily on transport and communication infrastructure investments to assist areas which are at a disadvantage due to their peripheral location and isolation. Furthermore, as the Union considers enlargement, some of these issues might be of wide European interest."

The developing countries are recelvmg generous Government Offices, and commercial organizations attention from experts, officials and academics drawn deserve our sincere thanks for their attention to our from a wide spectrum of specialist interests. Some of this many enquiries. In particular, we would like to thank effort is directed towards a solution of several of the the officials of the Planning Board and the Central world's most pressing problems, including ill-health, Statistical Office, Kuwait Municipality, University of under-nourishment, and rapid population growth, but Kuwait, and the Kuwait Oil Company. The following other workers are more concerned with the less immedi- individuals deserve our special thanks: Mr. Ahmad al- ate but nonetheless very significant theoretical aspects Duaij, Mr. Fouad al Hussaini, Mr. Hamid Shwaib, Mr. of the developing countries. This book is an attempt to Abdulaziz aI-Hamdan, Mr. Fouad Haddad, Mr. Ahmad bridge the gap between these two approaches. al-Haj, Mr. Marwan 'Adra', Mr. Muhammad Sukhon, At this present juncture in time we are faced with Professor Abdul Fattah Ismail, Professor Dawlat Sadiq, the realization that the experience of Europe or North Professor Muhammad Mutwalli, Dr. Muhammad Shar- nubi, His Excellency Ibrahim Shatti, Dr. Noel Brehony, America may be of limited assistance in the interpretation Professor W. B. Fisher, Dr. John Brebner, Dr. Alan of current trends in the developing world. Not only is Horan, Mrs.

This book is a natural extension of the SCOPE (Scientific Committee of Problems on the Environment) volumes on the carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) biogeochemical cycles and their interactions (Likens, 1981; Bolin and Cook, 1983). Substantial progress in the knowledge of these cycles has been made since publication of those volumes. In particular, the nature and extent of biological and inorganic interactions between these cycles have been identified, positive and negative feedbacks recognized and the relationship between the cycles and global environmental change preliminarily elucidated. In March 1991, a NATO Advanced Research Workshop was held for one week in Melreux, Belgium to reexamine the biogeochemical cycles of C, N, P and S on a variety of time and space scales from a holistic point of view. This book is the result of that workshop. The biogeochemical cycles of C, N, P and S are intimately tied to each other through biological productivity and subsequently to problems of global environmental change. These problems may be the most challenging facing humanity in the 21 st century. In the broadest sense, "global change" encompasses both changes to the status of the large, globally connected atmospheric, oceanic and terrestrial environments (e. g. tropospheric temperature increase) and change occurring as the result of nearly simultaneous local changes in many regions of the world (e. g. eutrophication).