Bücher veröffentlicht von Springer US

Knowledge Representation and Relation Nets introduces a fresh approach to knowledge representation that can be used to organize study material in a convenient, teachable and learnable form. The method extends and formalizes concept mapping by developing knowledge representation as a structure of concepts and the relationships among them. Such a formal description of analogy results in a controlled method of modeling `new' knowledge in terms of `existing' knowledge in teaching and learning situations, and its applications result in a consistent and well-organized approach to problem solving. Additionally, strategies for the presentation of study material to learners arise naturally in this representation. While the theory of relation nets is dealt with in detail in part of this book, the reader need not master the formal mathematics in order to apply the theory to this method of knowledge representation. To assist the reader, each chapter starts with a brief summary, and the main ideas are illustrated by examples. The reader is also given an intuitive view of the formal notions used in the applications by means of diagrams, informal descriptions, and simple sets of construction rules. Knowledge Representation and Relation Nets is an excellent source for teachers, courseware designers and researchers in knowledge representation, cognitive science, theories of learning, the psychology of education, and structural modeling.

The results of randomized trials evaluating the use of early or adjuvant systemic treatment for patients with resectable breast cancer provide an eloquent rebuttal to those who would argue that we have made no progress in the treatment of cancer. Many of the tumors that we have been most successful in curing with chemotherapy and other newer forms of treatment are relatively uncommon. In contrast, breast cancer continues to be the single most common malignancy among women in the western world, is increasingly a cause of death throughout Asia and Third-World countries, and remains one of the most substantial causes of cancer mortality world- wide. The use of mammography as a means of early detection has been shown to reduce breast cancer mortality by 25-35% among those popu- lations in which it is utilized. The use of adjuvant systemic treatment in appropriate patients provides a similar (and additional) reduction in breast cancer mortality. Few subjects have been so systematically studied in the history of medicine, and it seems fair to conclude that the value to adjuvant systemic therapy in prolonging the lives of women with breast cancer is more firmly supported by empirical evidence than even the more conventional or primary treatments using various combinations ofsurgery and radiotherapy.

Effective Polynomial Computation is an introduction to the algorithms of computer algebra. It discusses the basic algorithms for manipulating polynomials including factoring polynomials. These algorithms are discussed from both a theoretical and practical perspective. Those cases where theoretically optimal algorithms are inappropriate are discussed and the practical alternatives are explained. Effective Polynomial Computation provides much of the mathematical motivation of the algorithms discussed to help the reader appreciate the mathematical mechanisms underlying the algorithms, and so that the algorithms will not appear to be constructed out of whole cloth. Preparatory to the discussion of algorithms for polynomials, the first third of this book discusses related issues in elementary number theory. These results are either used in later algorithms (e.g. the discussion of lattices and Diophantine approximation), or analogs of the number theoretic algorithms are used for polynomial problems (e.g. Euclidean algorithm and p-adic numbers). Among the unique features of Effective Polynomial Computation is the detailed material on greatest common divisor and factoring algorithms for sparse multivariate polynomials. In addition, both deterministic and probabilistic algorithms for irreducibility testing of polynomials are discussed.

amounts can produce a deleterious effect on animals. In an attempt to quantify this potential for toxicity and to give sufficient margin for safety, JECFA has introduced an acceptable daily intake (ADI) level for food additives. For example, the ADI values granted for saccharin, aspartame, cyclamate, acesulfame-K and sucralose are 2. 5, 40, 11,9 and 1 3. 5 mg kg- body weight per day, respectively. Chapter 2 on regulatory aspects of low-calorie food elaborates these points. The additives that are to be consumed in large amounts, such as a fat replacement product like 'Olestra' or a new bulking material like 'polydextrose', present a more complex problem as far as the evaluation of their toxicity is concerned. Normal safety testing of an additive, such as a high-intensity sweetener, requires that the test animals are fed with a sufficiently high dosage in order to produce an effect and then on that basis an ADI value is calculated. In cases like 'Olestra' and 'polydex- trose', which are not normally present in diet or metabolised to dietary constituents, such an approach will obviously not be applicable, or of any use, in calculating an ADI value. Due to these factors the regulatory authorities have not yet been able to produce any guidelines for toxicity trials for additives that are to be taken in food in large quantities.

Considering the current interest in cellular regulation and intracellular signalling systems, it is surprising that the contribution of ADP-ribosylation reactions to the modulation of a variety of specific cell processes, in parallel with other post-translational modifications such as phosphorylation, has not been generally recognized. While it is not feasible to cover all aspects of ADP-ribosylation, the thirty-one articles contained in this volume provide a valuable overview of recent progress in the field within the context of cell control mechanisms. For the convenience of the reader, the various topics have been grouped into several sections: (a) poly(ADP-ribosyl)ation; (b) mono-ADP-ribosylation; (c) toxin mono-ADP-ribosylation; (d) inhibitors and activators; (e) protein modification with ADP-ribose and its analogues; and (f) non-modification forms of ADP-ribose. The contents of the individual chapters reflect the ideas of the contributors, many of whom have spent their careers attempting to resolve the biological functions of ADP-ribosylation. We hope that this publication will serve as a useful reference for those investigators that are new to the area as well as those who are actively studying ADP-ribosylation.

Throughout the world, head and neck cancer is a major threat to public health and a significant challenge to both clinicians and basic scientists. Despite extensive efforts in primary prevention, screening, early detection, and therapy, long-term survival rates have not improved substantially in the last three decades. This book covers a wide range of exciting new findings in both clinical and basic sciences as they are relevant to head and neck cancer. These findings have recently enhanced our understanding of head and neck carcinogenesis at the genetic and molecular levels, offering the promise of improved preventive and therapeutic strategies. This book will also present information on the important clinical advances that have been made in chemoprevention, organ preservation, and the simultaneous use of chemo- therapy and radiotherapy. The first part provides an overview of the etiology and biology of head and neck cancer, including an examination of human papillomaviruses in both benign and malignant lesions. This section also discusses the carcinogenic process at the genetic and molecular levels, as well as aberrant squamous differentiation; increased understanding of these areas has great potential to translate into new strategies for cancer prevention. The second part describes recent advances in developing a risk model for head and neck cancer, as well as the application of genetic susceptibility data in chemoprevention. This section also includes overviews of the status of chemoprevention trials and of the process of invasion and metastasis in head and neck cancer.

Lo, soul! seest thou not God's purpose from the first? The earth to be spann'd, connected by net-work From Passage to India! Walt Whitman, "e;Leaves of Grass"e;, 1900. The Internet is growing at a tremendous rate today. New services, such as telephony and multimedia, are being added to the pure data-delivery framework of yesterday. Such high demands on capacity could lead to a "e;bandwidth-crunch"e; at the core wide-area network resulting in degra- dation of service quality. Fortunately, technological innovations have emerged which can provide relief to the end-user to overcome the In- ternet's well-known delay and bandwidth limitations. At the physical layer, a major overhaul of existing networks has been envisaged from electronic media (such as twisted-pair and cable) to optical fibers - in the wide area, in the metropolitan area, and even in the local area set- tings. In order to exploit the immense bandwidth potential of the optical fiber, interesting multiplexing techniques have been developed over the years. Wavelength division multiplexing (WDM) is such a promising tech- nique in which multiple channels are operated along a single fiber si- multaneously, each on a different wavelength. These channels can be independently modulated to accommodate dissimilar bit rates and data formats, if so desired. Thus, WDM carves up the huge bandwidth of an optical fiber into channels whose bandwidths (1-10 Gbps) are compati- ble with peak electronic processing speed.