Nitrogen fixation is currently of great practical importance because the use of nitrogenous fertilizers has resulted in unacceptable levels of water pollution and the fact that these fertilizers are becoming steadily less economic both in cash terms and in utilization of fossil fuels for their manufacture. This book aims to present new findings in the field of nitrogen fixation and to reflect the influence on the subject of recent developments in biochemistry, molecular biology, genetic engineering and other biotechnologies. The book includes quantitative aspects of the subject, but the many practical difficulties for accurate field assessment of nitrogen fixation and its contribution to nitrogen cycles means that many assessments are either in conflict with each other or must be accepted as tentative. Although this book is concerned essentially with how nitrogen-fixing organisms function and why they are of practical importance, rather than with details of laboratory or field techniques, an appendix deals with the main methods of measurement of nitrogen fixation and some of the problems that must be faced.

This two-volume work is a testament to the abiding interest and human fascination with ammonites. We offer a new model to explain the morphogenesis of septa and the shell, we explore their habitats by the content of stable isotopes in their shells, we discuss the origin and later evolution of this important clade, and we deliver hypotheses on its demise. The Ammonoidea produced a great number of species that can be used in biostratigraphy and possibly, this is the macrofossil group, which has been used the most for that purpose. Nevertheless, many aspects of their anatomy, mode of life, development or paleobiogeographic distribution are still poorly known. Themes treated are biostratigraphy, paleoecology, paleoenvironment, paleobiogeography, evolution, phylogeny, and ontogeny. Advances such as an explosion of new information about ammonites, new technologies such as isotopic analysis, tomography and virtual paleontology in general, as well as continuous discovery of new fossil finds have given us the opportunity to present a comprehensive and timely "state of the art" compilation. Moreover, it also points the way for future studies to further enhance our understanding of this endlessly fascinating group of organisms.

This text is an overall view of nematology because I believe the science should be treated as a unified discipline. The differences in the biological habits of nematodes do not justify the separation of plant nematologists and animal nematologists, since the separation is not a reflection of any difIerences inherent to nematodes. Therefore, the book is arranged with a format that in the beginning chapters illustrates the similarities and se- quence of development of morphological characters among nematodes regardless of their biological habits. The later chapters illustrate the in- tegration of the evolutionary development of the parasitie habit from related free-living forms. Nematology is probably the last major discipline to establish its inde- pendence from the parent science of zoology. This natural evolvement of nematology has occurred because of the overwhelming accumulation of sophisticated information and research that reflects the unique relation- ships of nematodes to other forms of plant and animal life as weH as their relationships in other facets of the environment. N ematodes are inverte- brate animals that, like insects, are unusual in their great numbers and varieties, their smaH size (generally microscopic), their high degree of internal organization, and their virtually ubiquitous distribution. They oc- cupy almost every ecological niehe, often causing disease of humans, other animals, and plants. These activities often result in debility, death, or in the impairment and loss of food supply with consequent loss to producers and consumers.

This volume contains the papers presented in the NATO Advanced Research Workshop "Activation of Hormone and Growth Factor Receptors: Molecular Mechanisms and Consequences" held in Nafplion, Greece on September 25-30, 1988. The objective of NATO ARW is to assess the state of-the-art in a given scientific area and to formulate recommendations for future research in emerging areas of science by promoting international scientific contacts. In the Nafplion meeting this objective was reached by an international group of speakers, senior Greek scientists and graduates involved in relevant research areas. The Workshop was made possible by the generous support of the Scientific Council of NATO. We thank Drs. G. Sinclair and L.V. daCunha, Directors of the NATO ARW's and ASI's (Advanced Study Institutes) respectively, for their wholehearted support and advice. The International Union of Biochemistry awarded additional travel grants leading to increased international participation. Furthermore, the Secretariat of Science and Technology, the Ministry of Culture and Sciences and the National Hellenic Research Foundation contributed financially and by supporting personnel. We sincerely thank all these organizations for their support. Our heartful thanks are also extended to the Mayor of the Municipality of Nafplion, Mr.

The study of coelenterates is now one of the most active fields of invertebrate zoology. There are many reasons for this, and not everyone would agree on them, but certain facts stand out fairly clearly. One of them is that many of the people who study coelenterates do so simply because they are interested in the animals for their own sake. This, however, would be true for other invertebrate groups and cannot by itself explain the current boom in coelenterate work. The main reasons for all this activity seem to lie in the considerable concentration of research effort and funding into three broad, general areas of biology: marine ecology, cellular-developmental biology and neurobiology, in all of which coelenterates have a key role to play. They are the dominant organisms, or are involved in an important way, in a variety of marine habitats, of which coral reefs are only one, and this automatically ensures their claims on the attention of ecologists and marine scientists. Secondly, the convenience of hydra and some other hydroids as experimental animals has long made them a natural choice for a variety of studies on growth, nutrition, symbiosis, morphogenesis and sundry aspects of cell biology. Finally, the phylogenetic position of the coelenterates as the lowest metazoans having a nervous system makes them uniquely interesting to those neurobiologists and behaviorists who hope to gain insights into the functioning of higher nervous systems by working up from the lowest level.

Animal keepers have developed innovative ways to help zoo animals learn and grow. Learn how zookeepers keep animals healthy and happy with this fun and informative book. Created in collaboration with the Smithsonian Institution, this STEAM book will ignite a curiosity about STEAM topics through real-world examples. It features a hands-on STEAM challenge that is perfect for makerspaces and that guides students step-by-step through the engineering design process. Make STEAM career connections with career advice from actual Smithsonian employees working in STEAM fields. This book builds young readers' foundational literacy skills and is ideal for 1st grade students or children ages 5-7.

Parasites evolve under selective pressures which are different from those acting on free-living organisms. The aim of this textbook is to present these pressures and to show how they have shaped the ecology of parasites over evolutionary time. Broad theoretical concepts are explained simply and clearly and illustrated throughout with example organisms. The book will be an invaluable text for advanced undergraduate biologists who are studying evolutionary biology, ecology, population biology, parasitology and evoluationary ecology. It will also prove to be a valuable reference to postgraduate students and researchers in the same fields.

Recently there have been many advances in the understanding of the genetic basis of development and regular breakthroughs are being made in the field of tumour cell targeting. Both these areas of research are coming together in terms of their perception of programmed cell death. A broad introduction of the biological significance of cell death is followed by a major review of the significance of physiological cell death in tumours and the factors that influence it. The volume includes a consideration of the role and functions of lymphokines and their bearing on tumour cell targeting and cell killing. The interleukins, interferons and tumour necrotic factor (TNF) are presented in terms of their functional significance rather than in a sequential or systematic manner. This volume concentrates on the bases of biological or programmed cell death. Aspects of necrosis are, however, of necessity covered in comparative and technical terms. The central section on cell death in tumours is followed by a resume of the techniques employed in demonstrating cell death and this section closes with an appendix giving practical details of selected methods. It is hoped that the book may help potential research workers focus not only on the underlying molecular biology of programmed cell death but also provide impetus for the development of appropriate therapeutic regimes in tumour research.

An identification handbook containing descriptions of 974 species of non-gilled fungi in 277 genera and figures of 543 of them. There are two major keys to genera and a key to the species in each genus that contains more than one species. The fungi described and illustrated can nearly all be found in Great Britain. The book aims to stimulate interest in groups of fungi which have hitherto attracted relatively few workers. Resupinate fungi, club fungi, jelly fungi, brackets, earth stars, puffballs and so on are not difficult to identify with a little practice and many of them flourish and sporulate freely during the winter months and thus it is possible to study mycology all year round if all groups are studied. In this book measurements, except where otherwise stated, are in thousandths of a millimetre. Terms which may be unfamiliar are explained in the glossary and for quick reference genera in the two main sections are arranged in alphabetical order.

W. French Anderson, M.D. The publication of this book comes at an opportune time for the young field of human gene therapy. After a decade of long struggle at the laboratory bench and many long hours under the harsh lights of the federal review process, gene therapy has emerged as a legitimate scientific discipline. It is now time to move away from the period of questioning whether gene therapy will be a useful part of the physician armamentarium to begin to actively teach the concepts and practices that make gene therapy a reality. This book is a comprehensive collection of chapters that describe the basic biology and potential application of viruses as gene transfer reagents. It is not a coincidence that a modified virus was the reagent used in the first human gene therapy trials. Viruses have evolved with the human species (and most likely with all forms of life) to be the masters of gene transfer.

Initially believed to be inactive molecules, glycans are now considered essential for life, both under normal and pathological conditions.

This volume of the series "Biology of Extracellular Matrix " reviews the most recent findings on the role of glycans in the development of diseases and the possible therapeutic use of this class of molecules. It shows how the interaction of glycans with growth factors, growth factor binding proteins, extracellular proteases, protease inhibitors, chemokines, morphogens, and adhesive proteins regulates inflammation, infection, cancer, atherosclerosis, thrombosis and embryonic stem cell biology. Furthermore, an extensive survey about the structure and pharmacological effects of unique marine glycosaminoglycans is discussed as well as the possibility of using these glycans as therapeutic agents.

Helminths include one of the most diverse and geographically widespread groups of parasites which infect humans and animals. About 100 species have been reported from humans, usually producing asymptomatic infection or mild symptoms. However, about 20 species are of public health importance causing severe or even fatal infections. In many parts of Africa parasitic helminths are responsible for enormous economic losses, hampering rural development programmes and reducing the pace of economic growth. Many parasitic helminths are either zoonoses (diseases naturally transmitted between vertebrate animals and man) or have evolved from animal parasites. The modification of the environment through wars, famine and the ever expanding and increasingly mobile human population brings people into close contact with new environments and wildlife species which makes the study and control of zoonoses of special interest and complexity. In Africa, the transmission of helminth parasites is highly influenced by the ever changing social and cultural differences between diverse groups of peoples and their interaction with wild and domestic animals. It is not surprising, therefore, that approaches to the study and control of parasitic zoonoses require intersectoral cooperation between physicians, veterinarians, parasitologists, zoologists, demographers, anthropologists, engineers and economists to provide the breadth of knowledge and expertise required to develop our understanding of these diseases and to devise methods for their control. This book provides a selective compilation of parasitic helminths, many of which are zoonoses which create important economic and public health problems in Africa.