Survey Deals Research Articles

Hypermedia Models

This survey deals with questions of the organization and structuring of information. Hypermedia models of three basic categories are considered: (1) models of data structures, in which information is laid; (2) models of processes, which describe the semantics of the linking and browsing; and (3) combinational models that include structural and behavioral aspects of hypermedia.

A historical perspective on telecommunications network synchronization

Network synchronization, at first unknown and considered irrelevant to the operation and performance of telecommunications networks, has played an increasingly important role throughout the evolution of telecommunications, especially since transmission and switching became digital. This survey deals with telecommunications network synchronization from a historical point of view, aiming to show how network synchronization issues have evolved with telephone networks over the last 30 years, beginning with old FDM networks up to the latest technologies through PDH, SDH/SONET, and ATM. For each case, the different synchronization needs and the peculiar techniques of timing transfer and distribution are pointed out, thus providing a comprehensive overview of the evolution steps of telecommunications network synchronization.

Quantitative vegetation ecology in Denmark

Abstract. This survey deals with quantitative vegetation ecology in Denmark since the pioneering period dominated by E. Warming, C. Raunkiær and Johs. Iversen. Main topics of this survey are quantitative vegetation description, mainly based on the classical work of Warming, vegetation classification and community ecology, conservation biology and management, vegetation history and palaeoecology, vegetation dynamics, forest ecology and phytogeography. It is concluded that few Danish studies have dealt with the development of models and theories and the application of multivariate statistics.

The onset of schizophrenia

This survey deals with findings and results of systematic clinical-psychiatric and -psychological studies of the true onset of schizophrenia and its significance. Many symptoms precede the psychotic onset of schizophrenia. These have been described by Huber as ‘basic symptoms’, who developed the concept of basic stages and basic symptoms gradually since the 1950's. The basic symptoms are experiential and not behavioral in kind and only recognizable by the self-reports of the patients. They are rateable using a structural scale (Bonn Schedule for the Assessment of Basic Symptoms: BSABS) described below. They form the two precursor syndromes: (1) prodromes lead on average within 3.3 years to a psychotic episode; and (2) outpost syndromes that are completely remitting on average within 5 months and precede the first psychotic episode on average 10 years. Basic symptoms can be further divided into level 1 (nonspecific) and level 2 (characteristic) basic symptoms. Basic symptoms, positive and negative symptoms have to be differentiated; they also develop in this chronological sequence: first non-specific, then characteristic basic symptoms, followed on average many years later by positive symptoms, and, finally by negative symptoms. Structured ratings of the basic symptoms and their recognition in the precursor syndromes enables physicians to detect early symptoms of a schizophrenic illness that, if treated at this stage, can lead to a better long-term outcome.

Protecting niobium and tantalum from high-temperature gas corrosion (review)

The survey deals with methods of raising the heat resistance of niobium, tantalum, and alloys, based on them, and the main lines of development are distinguished for protective coatings that increase the working life of refractory-metal specimens.

Functional significance of polymorphism among MHC class II gene promoters.

The functional significance of polymorphism among MHC class II promoters in man and mouse is here reviewed, mainly in terms of the hypothesis of differential expression. The hypothesis proposes that differences between antigen-presenting cells in MHC class II expression exert a co-dominant effect on the Th1-Th2 cytokine balance, such that class II molecules of one type come to control to a greater extent the production of one group of cytokines, and those of another type the production of the alternative group. The survey deals with the influence of signal strength and antigen-presenting cell type on T-cell subset differentiation; functional differences between MHC class II molecules not obviously related to determinant selection; disease protection mediated by HLA alleles; mechanisms possibly responsible for allotypic and isotypic bias; overdominance (heterozygous advantage) in selection for expression of class II alleles; MHC class II promoter structure and function; inter-locus and inter-allele variability within human MHC class II gene upstream regulatory regions; a comparison of these polymorphisms in mouse and man; read-out of class II promoter function; and a comparison with expression of MHC class I. We conclude that the evidence that this variation is functionally active (i.e. controls expression) is increasing, but is not yet compelling. The crucial test still to come, we suggest, is whether or not the biological effects attributable to this polymorphism will line up with molecular studies on expression.

Agricultural development vs biodiversity conservation: the Mediterranean semiarid vegetation in El Ejido (Almer�a, southeastern Spain)

The development of a greenhouse agriculture in the traditionally impoverished region of Poniente de Almeria, on the Mediterranean coast of Spain, has caused an enormous rise in living standards. However, the environmental impact of this badly-planned growth threatens the every dynamics of the exploitation system. A special examination must be made of the use of the three major resources responsible for the functioning of greenhouse production and its impact on the ecosystems and particularly on the vegetation. These resources are: clayey soils, sand from fossil dunes and ground water. While the use of the clayey soils and sand have negative effects on the conservation of ecologically valuable communities found nowhere else in Europe, ground water overexploitation has produced an increase in salinity in most of the aquifers. Of these, sand has been by far the best monitored resource and restoration programmes have been implemented in the extraction zones. This survey deals with the recent evolution of areas where the arto (Maytenus senegalensis subsp. europaeus) and the sabina (Juniperus phoenicea subsp. turbinata) have long been the dominant species, although the presence of the former is nowadays notoriously diminished. The study is based on aerial photographs taken in 1957, 1977 and 1985, together with our own field work. Curiously enough, all this man-made process of degradation has stimulated ornithological diversity. Finally, we propose here some measures which aim to preserve the most important enclaves of these Mediterranean shrub formations, specially those of the arto, since sabina-dominated communities already belong to existing conservation areas.

Jeux, coopération et problèmes environnementaux globaux

Games, co-operation and global environmental change This survey deals with co-operation in the presence of global environmental change. We examine the influence of the different factors which play a significant role in such a context. Thus, by using game theory representation, we can note that there are many possible co-operative behaviours : some countries act unilaterally when others join a coalition. Consequently, we can't study these problems in a prisonner's dilemma perspective. It seems more realistic to evoke the chicken game for a collective co-operation, and the trust game (or the sequential prisonner's dilemma with ecological conscience ) for an unilateral commitment. In fact the major result of the various works is that a solution exists for global environmental problems, but it is not necessarily a universal solution : co-operation is generally the work of a limited group of countries.

Le littoral, espace de médiations - Cultes des monts Sengen, Asama, Aomine et systèmes de représentations chez les gens de mer de la côte orientale de la péninsule de Kii

The first part of the survey deals with the festival in honor of the sea- and mountain-god Sengen in three small harbors of Mie prefecture. Hōza and Isozaki are fishing harbors but Azena is a place where women-divers collect shells and sea-weeds. Even today, in this region, the eastern coastal range of Kii peninsula, these festivals share much in common: purification rites, formulation, the communities' banquets and festivities open to all, and the worship of Sengen. The main worship takes place on heights devoted to Sengen where ornate bonden poles are planted. At the same time, these sacred heights play the role of sea-marks helping the sailors and of a kind of relay or replica of the Japanese sacred mountains. The worship practiced there goes back to archaic marine religious traditions but has been very conspicuously influenced by the kō pilgrims' sodalities which have been controlled by the mountain-ascetics of Shugendō for a long period. Taboos of Shugendō as women prohibiting could have been found somewhat compatible with sea-societies haunted by the fear of defilements. These special features of the cult of Sengen, unified by the Shugendō of Mount Fuji, of which Sengen is the God, and confined to a clearly defined coastal area, pose the wider problem of the convergence of maritime and mountain religious spheres. In order to better appreciate the influence exerted by the assimilation of sea-related worship by a unifying mountain-worship and of the following partial occlusion of what constitutes the specificity of the sea-faring peoples, the second part of the survey is extended to cover two famous mountain-temples of the hinterland of the eastern Kii seaside. The first is the oku no in of the Kongōshōji on Mount Asama in the Ise country. Its takemairi is a local cult for the dead which can be seen as a duplicate of funerary practices related to a marine netherworld still ongoing during the New Year period on the not so distant beaches of the Kii seaside. The second is the Shōfukuji of Mount Aomine in the Shima country. Two tales about its foundation are extant. Both can be understood as referring to the relocation of a sea-deity (Ōsatsu Kannon) who was transformed into a mountain-deity. Her brilliance shines far away on the sea and she is still venerated by the sea-faring people spanning the whole of Japan's Pacific coast. This attempt to relocate the worship of Sengen inside the history of the systems of representation of the sea-faring people is only an element of a survey which should cover all the coastal regions and which could also focus on a complex of symbols as suggestive as Mount Fuji itself We can observe a paradigm shift in a seaside which is first seen as a departure point toward a netherworld beyond the sea or as a refuge for gods or men from the outside world, and then is considered to be a line of reefs and heights being the forefront of the land (riku) used for mountain worship. This shift shows a process of "sedentarisation" with ideological intent. The coastal populations, heirs of the "nomads of the sea", when redefining their vision of the world, visible and invisible, see the occlusion of their genuine world, the sea. Deciphering the process of occluding the world of the sea gives a new approach to the vision that the Japanese society has of itself and transmits to others, its statements both of identity and of otherness.

Nonlinear Boltzmann Equation Solutions and Applications to Fluid Dynamics

This paper provides a review of the mathematical results on the solution of the nonlinear Boltzmann equation. The survey deals both with analytical and computational aspects: Mathematical formulation of problems, initial and/or boundary value problems, a survey of the qualitative analysis of solutions, and computational treatment of fluid dynamical problems. A discussion of some problems deserving further study concludes this work.

The application of thermal analysis to the study of ignition processes of solid fuels

The present literature survey deals with the application of thermal analysis and associated coupled techniques to the study of the self-ignition processes of solid fuels. These techniques make possible the assessment of the antioxidative action of inorganic and organic inhibitors which prevent the coals self-igniting. Thermal analysis is regarded as a method for investigating oil-dispersed fuel suspensions as fossil fuel substitutes.

1/f noise sources

This survey deals with 1/f noise in homogeneous semiconductor samples. A distinction is made between mobility noise and number noise. It is shown that there always is mobility noise with an /spl alpha/ value with a magnitude in the order of 10/sup -4/. Damaging the crystal has a strong influence on /spl alpha/, /spl alpha/ may increase by orders of magnitude. Some theoretical models are briefly discussed none of them can explain all experimental results. The /spl alpha/ values of several semiconductors are given. These values can be used in calculations of 1/f noise in devices. >

Continuity of spectrum and spectral radius in Banach algebras

This survey deals with necessary and/or sufficient conditions for continuity of the spectrum and spectral radius functions at a point of a Banach algebra. Introduction. Let L be a complex Banach algebra. If L has no identity, let L denote the Banach algebra obtained by canonical adjunction of an identity to L, whereas we set L = L if L has an identity. Furthermore, let KC denote the set of compact nonempty subsets of the complex plane C, endowed with the Hausdorff metric ∆. We deal with continuity of the spectrum function σ : L → KC and of the spectral radius function r : L → R (where σ(a) and r(a) denote respectively the spectrum and the spectral radius of a in L for any a ∈ L). The following inequality is not difficult to verify: (1) |r(a)− r(b)| ≤ ∆(σ(a) , σ(b)) for any a, b ∈ L. Hence continuity of σ implies continuity of r. If Ω is a subset of a topological space Ξ, we denote by Ω and Ω ◦ the closure and interior of Ω in Ξ, respectively. If L is commutative, by the Gelfand representation theorem (see [R], 3.1.6, 3.1.11 and 3.1.20) there exist a locally compact Hausdorff space X and a continuous homomorphism Γ , from L into the Banach algebra C0(X) of complex-valued continuous functions on X which vanish at infinity, such that σ(a) = â(X) (where 1991 Mathematics Subject Classification: Primary 46H99. The paper is in final form and no version of it will be published elsewhere.

Scheduling theory and practice: Minsk group results

The paper surveys scheduling theory results obtained mainly at the Institute of Engineering Cybernetics of the Academy of Sciences of Belarus, and published on the whole in Russian. The survey deals with the job-shop, flow-shop and open-shop scheduling problems, and with sequencing jobs on one machine and on a set of parallel machines. The more complicated problems and applied aspects of scheduling theory are also observed. Some trends of further research in scheduling and sequencing are outlined.

Zur magnetischen Ortung bioelektrischer Quellen Teil 1: Ortung einzelner und mehrerer Stromdipole

Electric activity of nerve and muscle cells can be noninvasively located by analyzing their magnetic field. Assumptions about the electric sources and the distribution of the electric conductivity of the object under investigation have to be made. The first part of this survey deals with the location of single current dipoles in conductors of simple geometries. An analysis of the time dependence of the magnetic field permits to estimate the number of independent active current dipoles. The second part deals with the localization of current distributions and gives examples of clinical applications.

Die osteoplastische Versorgung des Kieferspaltes —ein Fortschritt für die kieferorthopädische Behandlung des Spaltpatienten?

This survey deals with problems of osteoplastic supply of the cleft from the orthodontic point of view. Remarkable parallels exist between primary and secondary osteoplasty: The involution stability of the alveolar process is only presented in a space-less tooth line. Therefore, the primary goal is to guarantee tooth eruption in the former cleft area. However, the antalogous bone graft in the former cleft area has to have a similar structure as adjacent alveolar bone. If tooth germs pass through the bone graft, an own parodont can be built up in the course of eruption. This is applicable to both dentitions. Accordingly, the osteoplasty of clefts is the most important prerequisite for stable treatment results and a healthy dentition.

Large lakes: ecological structure and function

This comprehensive and up-to-date survey deals with the distribution and the structural and functional properties of the large lakes of the world. For the first time aquatic physicists, chemists, sedimentologists and a wide range of freshwater biologists joined in order to assess our current understanding of large lakes. Special interest focuses on physical factors, in particular wind stress, internal waves and current jets which have a particularly strong impact on large lakes. Since they also possess a true free-water zone, large lakes can ideally serve as model oceans.

A look at various procedures for evaluation of “best” values in geochemical reference materials

The absolute or “true” content of a particular constituent in geochemical reference materials can never be known. An alternative is the assignment of a “best” value which should approach the “truth” as closely as possible. This survey deals with problems encountered in the evaluation of those “best” values. Compilations, plotting of the data, check for normality, outlier elimination, and measures of central tendency are described. Examples of procedures frequently used for deriving “best” values are also presented.

Technological applications of solid state ionics

Solid state ionics materials have been extensively developed during the last 10 years and theory and applications of solid electrolytes as well as insertion compounds have begun to converge into a coherent field. The solid state ionics technology is the result of progress in two categories of materials: superionic conductors and insertion compounds. A considerable effort has been undertaken these last few years to increase knowledge of these materials, and the most recent advances in this field are discussed with the related devices. This development has found applications in the domain of electrochemical devices, such as batteries, fuel cells, sensors and electrochemical measuring systems. This literature survey deals with applications of solid state ionics, including different groups of materials. The performance of these devices is discussed and foreseeable applications with the pertinent properties of the constituting materials are described. An overview of thin film technologies and microbatteries is also given.

Fatal intoxications in the age group 15?34 years in Denmark in 1984 and 1985

This survey deals with the Danish part of a study on fatal intoxications conducted in the Nordic countries in 1984 and 1985 with special reference to drug addicts. There were 315 cases of fatal intoxications in people 15–34 years of age. These were examined at the Forensic Institutes in Denmark and described with reference to cause of death, sex, age and drug addiction. Of the deceased, 194 were drug addicts according to a specific definition of this term. Women accounted for 28% of all the fatalities investigated in the study and 24% of those in addicts. More than 90% of the deaths were caused by drugs, with ethanol as a contributory factor in approximately 40% of cases. Deaths caused by heroin/morphine predominated, causing 50% of the deaths among drug addicts, but legal drugs, such as dextropropoxyphene, methadone and ketobemidone were also frequent causes of death in this group. In half the cases the concentration of morphine in blood following injection of heroin/morphine was found to be equal to or less than 0.5 μmol/ kg, and in only about one-tenth of cases was the blood concentration above 2.0 μmol/kg.