Bücher veröffentlicht von Springer Netherlands

Approach your problems from It isn't that they can't see the right end and begin with the solution. the answers. Then one day, It is that they can't see the perhaps you will find the problem. final question. G.K. Chesterton. The Scandal 'The Hermit Clad 1n Crane of Father Brown 'The Point of Feathers' in R. van Gulik's a Pin'. The Chinese Maze Murders. Growing specialisation and diversification have brought a host of monographs and textbooks on increasingly specialized topics. However, the "e;tree"e; of knowledge of mathematics and related fields does not grow only by putting forth new branches. It also happens, quite often in fact, that branches wich were thought to be completely disparate are suddenly seen to be related. Further, the kind and level of sophistication of mathematics applied in various sciences has changed drastically in recent years: measure theory is used (non-trivially) in regional and theoretical economics; algebraic geometry interacts with physics; the Minkowsky lemma, coding theory and the structure of water meet one another in packing and covering theory; quantum fields, crystal defects and mathematical programming profit from homotopy theory; Lie algebras are relevant to filtering; and prediction and electrical engineering can use Stein spaces. And in addition to this there are such new emerging subdisciplines as "e;experimental mathematics"e;, "e;CFD"e; , "e;completely integrable systems"e;, "e;chaos, synergetics and large-scale order"e;, which are almost impossible to fit into the existing classification schemes. They draw upon widely different sections of mathematics.

It goes almost without saying that there has been a marked increase in the incidence of sexually transmitted diseases throughout the world in the past two to three decades. Indeed, despite the progress that has been made in methods of diagnosis and treatment, the sexually transmitted diseases as a whole are the most common communicable diseases and as such constitute an important health problem. The increase in incidence may be accounted for by changes in sexual behaviour, the introduction of contraceptives and the increasing mobility of the population. In addition, during the same time period, the number of infectious agents recognized as being sexually transmitted has increased considerably. These include Chlamydia trachomatis, herpes simplex virus, cytomegalovirus and hepatitis B virus. Indeed, some are as dependent on sexual transmission as the agents which cause the traditional venereal diseases and collectively they cause morbidity which has out-stripped that caused by gonorrhoea and syphilis. It could almost be said that to know the sexually transmitted diseases is to know micro- biology. However, the approach taken in this book has not been to consider individual infectious agents and evaluate what they do and do not cause but to consider clinical conditions and what might be responsible for them. To cover the complete spectrum of the sexually transmitted diseases in a comprehensive way now takes a text book of massive proportion.

Polymers are permeable, whilst ceramics, glasses and metals are gener- ally impermeable. This may seem a disadvantage in that polymeric containers may allow loss or contamination of their contents and aggressive substances such as water will diffuse into polymeric struc- tures such as adhesive joints or fibre-reinforced composites and cause weakening. However, in some cases permeability is an advantage, and one particular area where this is so is in the use of polymers in drug delivery systems. Also, without permeable polymers, we would not enjoy the wide range of dyed fabrics used in clothing and furnishing. The fundamental reason for the permeability of polymers is their relatively high level of molecular motion, a factor which also leads to their high levels of creep in comparison with ceramics, glasses and metals. The aim of this volume is to examine some timely applied aspects of polymer permeability. In the first chapter basic issues in the mathema- tics of diffusion are introduced, and this is followed by two chapters where the fundamental aspects of diffusion in polymers are presented. The following chapters, then, each examine some area of applied science where permeability is a key issue. Each chapter is reasonably self-contained and intended to be informative without frequent outside reference. This inevitably leads to some repetition, but it is hoped that this is not excessive.

A wide variety of plants, ranging in size from forest floor herbs to giant canopy trees, rely on animals to disperse their seeds. Typical values of the proportion of tropical vascular plants that produce fleshy fruits and have animal-dispersed seeds range from 50-90%, depending on habitat. In this section, the authors discuss this mutualism from the plant's perspective. Herrera begins by challenging the notion that plant traits traditionally interpreted as being the product of fruit-frugivore coevolution really are the outcome of a response-counter-response kind of evolutionary process. He uses examples of congeneric plants living in very different biotic and abiotic environments and whose fossilizable characteristics have not changed over long periods of time to argue that there exists little or no basis for assuming that gradualistic change and environmental tracking characterizes the interactions between plants and their vertebrate seed dispersers. A common theme that runs through the papers by Herrera, Denslow et at. , and Stiles and White is the importance of the 'fruiting environment' (i. e. the spatial relationships of conspecific and non-conspecific fruiting plants) on rates of fruit removal and patterns of seed rain. Herrera and Denslow et at. point out that this environment is largely outside the control of individual plant species and, as a result, closely coevolved interactions between vertebrates and plants are unlikely to evolve.