bluuebunny/crossref_metadata_2025 huggingface dataset:
Proof and Disproof in Formal Logic
Authors: Bornat Richard
Published: November 2023

Proof and Disproof in Formal Logic is a lively and entertaining introduction to formal logic providing an excellent insight into how a simple logic works. Formal logic allows you to check a logical claim without considering what the claim means. This highly abstracted idea is an essential and practical part of computer science. The idea of a formal system-a collection of rules and axioms, which define a universe of logical proofs-is what gives us programming languages and modern-day programming. This book concentrates on using logic as a tool: making and using formal proofs and disproofs of particular logical claims. The logic it uses-natural deduction-is very small and very simple; working with it helps you see how large mathematical universes can be built on small foundations. The book is divided into four parts: Part I “Basics” gives an introduction to formal logic with a short history of logic and explanations of some technical words. Part II “Formal Syntactic Proof” show you how to do calculations in a formal system where you are guided by shapes and never need to think about meaning. Your experiments are aided by Jape, which can operate as both inquisitor and oracle. Part III “Formal Semantic Disproof” shows you how to construct mathematical counterexamples to shoe that proof is impossible. Jape can check the counterexamples you build. Part IV “ Program Specification and Proof” describes how to apply your logical understanding to a real computer science problem, the accurate description and verification of programs. Jape helps, as far as arithmetic allows. Aimed at undergraduates and graduates in computer science, logic, mathematics and philosophy, the text includes reference to and exercises based on the computer software package Jape, an interactive teaching and research tool designed and hosted by the author that is freely available on the web.
Models of Peano Arithmetic
Authors: Kaye Richard
Published: November 2023

Nonstandard models of arithmetic are of interest to mathematicians through the presence of infinite (or nonstandard) integers and the various properties they inherit from the finite integers. Since their introduction in the 1930s (by Skolem and Gödel ), they have come to play an important role in model theory, and in combinatorics through independence results such as the Paris-Harrington theorem. This book is an introduction to these developments, and stresses the interplay between the first-order theory, recursion-theoretic aspects, and the structural properties of these models. Prerequisites have been kept to a minimum. A basic grounding in elementary model theory and a familiarity with the notions of recursive, primitive recursive, and r.e. sets will be sufficient. Consequently, the book should be suitable for postgraduate students coming to the subject for the first time and a variety of exercises of varying degrees of difficulty will help to further the reader's understanding. Beginning with Gödel's incompleteness theorem, the book covers the prime models, cofinal extensions, end extensions, Gaifman's construction of a definable type, Tennenbaum's theorem, Friedman's theorem and subsequent work on indicators, and culminates in a chapter on recursive saturation and resplendency.
Discretely ordered rings
Authors: Kaye Richard
Published: November 2023

We start our study of models of arithmetic in earnest by writing down some simple axioms that are obviously true in ℕ. The resulting theory, PA− , is described in Section 2.1 and is our ‘base theory’ to which we shall later add induction axioms. PA- has some very nice features which we explore in this chapter. In particular we will show in Section 2.2 that any model of PA- may be regarded as an end-extension of the standard model, and we introduce the notion of a Σ1 sentence, and show that PA- is strong enough to prove all true Σ1 sentences.
Riemannian Geometry
Authors: Willmore T J
Published: November 2023

Developments in this field have been so extensive since the author's work Introduction to Differential Geometry that a new book with particular emphasis on recent work in Riemannian geometry is clearly necessary. This new work includes an elementary account of twistor spaces which will interest both applied mathematicians and physicists as well as presenting recent developments in the theory of harmonic spaces, commutative spaces, and mean-value theorems previously only available in research papers. The final chapter provides the only account available in book form of manifolds known as `Willmore surfaces', illustrated by a series of computer-generated pictures.
Numbers and Shapes Revisited
Authors: Cofman Judita
Published: November 2023

Mathematics is primarily concerned with problem solving, and there is no better way of gaining an understanding of mathematics than by developing the independent thinking and ability to solve problems (and to set them). The mathematics syllabuses in today's secondary schools contain a wide range of notions and basic facts from various mathematical disciplines. Pupils interested in mathematics should be encouraged to explore the connections between the different topics they encounter, and this book attempts to help in pointing out these connections. By focusing attention on the links between patterns of numbers and shapes, and on between algebraic relations and geometric and combinatorial configurations, the book aims to * motivate deeper study of the concepts related to elementary mathematics * emphasize the importance of the interrelations between mathematical phenomena * foster the interplay of ideas involved in problem solving The material is presented in the form of problems and will prove invaluable and enjoyable for pupils, their teachers, and those studying mathematics or its teaching at university.
Moving Finite Elements
Authors: Baines M J
Published: November 2023

This book is mainly concerned with finite element methods for time-dependent partial differential equations when the grids are allowed to move in time, but also describes grid generation techniques which include grid adjustment. The mechanism for grid movement derives from a generalization of the residual minimization technique which is familiar from the Galerkin finite element method. The book brings together most of the work done over the last decade or so which has been stimulated by Miller's original idea, and discusses the interrelationships between the techniques of the method and the established ideas of the method of characteristics, Hamilton's equations, the Legendre transformation, and grid equidistribution. The book highlights the issues involved and should provide the reader with a clear view of the current state of the subject and prompt further research.
Congruence Theory
Authors: Rose H E
Published: November 2023

By universal agreement C. F. Gauss (1777-1855) was a mathematical genius of the highest order, to be considered alongside such giants as Newton and Einstein. He made many discoveries both inside and outside mathematics, but in his time he was probably best known as an astronomer—he was director of the Gottingen Observatory for many years. Number theory was one of his great passions he called it the ·Queen of Mathematics·. In 1801, at the age of 24. he published one of the classics of mathematical literature. Disquisitiones Arithmeticae, which contained a wealth of new ideas and theorems and which laid the foundation for modern number theory. A translation has been published (Gauss 1966) and the reader should try to study it. Many of the results presented below first appeared in Gauss’s classic, particularly those concerning quadratic reciprocity, primitive roots. and quadratic form theory.
A probabilistic round-off error propagation model. Application to the eigenvalue problem
Authors: Chatelin Francise , Brunet Marie Christine
Published: November 2023

It is often assumed that round-off error propagation is a statistical phenomenon, but relatively few studies have been carried out to test the validity of this assumption, and, if proved valid, to extract quantified information for the control of this error propagation. We propose a probabilistic model for round-off propagation which relies on two basic assumptions. The main result is that if the solution depends analytically on a perturbation of the problem, then for a large class of stable algorithms one can compute a confidence interval around the computed solution which contains the exact solution up to a given probability.
Non-monotonic Learning
Authors: Bain M , Muggleton S H
Published: November 2023

This paper addresses methods of specializing first-order theories within the context of incremental learning systems. We demonstrate the short comings of existing first-order incremental learning systems with regard to their specialization mechanisms. We prove that these shortcomings are fundamental to the use of classical logic. In particular, minimal ‘correcting’ specializations are not always obtainable within this frame work. We propose instead the adoption of a specialization scheme based on an existing non-monotonic logic formalism.
Deriving the Learning Bias from Rule Properties
Authors: Ganascia J G
Published: November 2023

To guide learning, the ‘learning bias’ has to be defined with accuracy, even if it has to be modified when the results do not match expectations. This needs knowledge of the semantics of the various aspects of the learning bias: representation formalism, description language, and syntactico-semantical constraints applied to the learning assumptions. In this paper we try to show these various aspects and demonstrate how a new system Ch a r a de , provides some of these aspects with semantics, thanks to the introduction of the notion of ‘system of rules’.
Reacting, Planning, and Learning in an Autonomous Agent
Authors: Benson Scott , Nilsson Nils J
Published: November 2023

We present an autonomous agent architecture and its component subsystems that integrate important abilities needed for robust, flexible performance in dynamic environments. These abilities involve appropriate reaction to environmental situations given the agent’s goals; selective attention to multiple, competing goals; planning new action routines when innovation beyond designer-provided routines is necessary; and learning the effects of actions so that the planner can use them to build ever more reliable plans. The teleo-reactive format allows actions to be closely coupled to continuous environmental feedback and is also especially compatible with conventional AI planning and learning mechanisms. The workings of the proposed architecture and its subsystems are illustrated in a simulated robot domain. We conclude by noting areas where future work is needed.
Automated Deduction in Multiple-valued Logics
Authors: Hahnle Reiner
Published: November 2023

This book constitutes a self-contained and unified approach to automated reasoning in multiple-valued logics (MVL) developed by the author. Moreover, it contains a virtually complete account of other approaches to automated reasoning in MVL. This is the first overview of this subfield of automated reasoning ever given. Finally, a variety of applications of automated reasoning in MVL including several short case studies are listed. Automated reasoning in non-classical logics is an essential subtask of many AI applications. Applications of MVL in particular include, for instance, hardware and software verification, reasoning with incomplete or inconsistent knowledge, and natural language processing. Therefore, efficient theorem proving methods in MVL are essential. In the historical part of the book it is demonstrated why existing approaches are inadequate. In the original part a simple, but powerful, concept called 'sets-as-signs' is introduced in the context of semantic tableaux, and subsequently is applied to a variety of calculi including resolution and dissolution. It is shown that 'sets-as-signs' yields a many-valued extension of the well-known relationship between classical logic and integer programming. As a consequence, automated reasoning in infinitely-valued logics can be done uniformly and efficiently for the first time.
Salp and pyrosomid blooms and their importance in biogeochemical cycles
Authors: Andersen V
Published: November 2023

The importance of salps and pyrosomas in biogeochemical cycles is related to their well-known periodical occurrence in vast swarms and to the way that they feed on phytoplankton. During the last 30 years, a large effort has been devoted to understanding the nutritional ecology of salps, revealing their high grazing impact on phytoplankton populations and their role in the downward flux of matter. In contrast, little attention has been paid, until recently, to the nutritional ecology of pyrosomas. However, they also have an important grazing impact while swarming, and produce very large numbers of faecal pellets. Estimation of the ecological and biogeochemical importance of salps has given rise to different types of models. Salps and pyrosomas are found periodically in dense swarms in various areas of the world oceans. The nutritional ecology of salps is characterized by: (1) very high filtration rates; (2) removal of minute particles and microorganisms with high efficiency; (3) high defaecation rates; and (4) production of large faecal pellets which sink rapidly. Moreover, the faecal material is enriched in several elements (e.g. carbon, nitrogen, calcium, and aluminium) compared to the salp itself, and degradation of the faecal pellets of oceanic salps is very slow (Yoon, 1995; see Yoon et al., 1996).
The abundance, distribution, and ecologi,cal impact of doliolids
Authors: Deibel D
Published: November 2023

The doliolid life cycle is complex (Chapter 1), with obligatory alternation of sexual and polymorphic asexual generations; in different doliolids, there are varying degrees of multiplication at sexual and asexual stages, and in one species there is a special short cycle. In brief, as summarized in Fig. 11.1, sexual gonozooids liberate planktonic eggs (usually cross-fertilized) that develop via a short larval stage into asexual oozooids. From a ventral stolon in the oozooid, buds form which migrate around to a dorsal caudal cadophore. The buds are of two kinds, the trophozooids being devoted to nourishing the colony (by this stage, the old oozooid or old nurse has lost all internal organs except heart and brain), whilst the phorozooids bear buds that develop
Diversity within populations
Authors: Brakefield Paul M , Shreeve Tim G
Published: November 2023

Within any butterfly population no two individuals are identical. This applies both to their genes or genotype and to their phenotype or set of individual characteristics resulting from interactions between the genes and the environment during development. The reproductive success or fitness of an individual depends on how well its phenotype is adapted or fitted to the environment which it experiences. Some species of butterfly exhibit discrete genetic forms which differ in wing pattern and which occur together within populations. Research on such poly¬morphisms has contributed much to our under¬ standing of the processes of adaptation to the environment. Having first introduced some basic concepts, this chapter describes work on poly¬morphisms in butterflies together with recent insights into how wing patterns are developed. Rare aberrations much beloved by butterfly collectors (see Russwurm 1978) are not considered in detail here since they are unlikely to be significant in evolution¬ ary terms even when they have a genetic basis (see Fig. 8.1).
Genetic relatedness and its components in polygynous colonies of social insects
Authors: Queller David C
Published: November 2023

Polygyny presents an obvious problem for the evolution and maintenance of insect societies. If many queens are laying eggs in a colony, there will be many matrilines among the progeny, and genetic relatedness among the progeny should therefore be low. This has serious consequences for the maintenance of worker behaviour. Hamilton (1964a ,b) showed that genetic relatedness is what fuels the engine of eusociality. Workers can evolve to give up their own reproduction only if they receive some genetic benefit through aiding other relatives.
The maintenance of high genetic relatedness in multi-queen colonies of social wasps
Authors: Hughes Colin R , Queller David C , Strassmann Joan E , Solís Carlos R , NegrónSotomayor Jorge A , Gastreich Karin R
Published: November 2023

Since Hamilton (1964a,ft) presented his theory of inclusive fitness, accounts of the evolution of insect societies have had to concern themselves with genetic relatedness. In the eusocial insects, workers forgo most or all of their own reproduction and instead help to rear the progeny of their colonys queens. Genes promoting such worker behaviour would inevitably be eliminated if workers were unrelated to the queens progeny. But genes promoting worker behaviour can make up for the lack of direct reproduction by workers because copies of the genes are present in the relatives being aided.
Distribution and ecology of queen number in ants of the genus myrmica
Authors: Elmes Graham W , Keller Laurent
Published: November 2023

The role of ecological factors in regulating queen number in social insects has recently been the subject of considerable interest (e.g. Hölldobler and Wilson 1977; Nonacs 1988; Reeve 1991). For instance, it has been postulated that polygyny is favoured under certain ecological conditions such as stable long-lived habitats; or alternatively, in circumstances of frequent colony moves in which the probability of workers losing contact with their queens is relatively high (Holldobler and Wilson 1977; Herbers 1986, this volume; Nonacs 1988; Rosengren et al. this volume).
Selective pressures on pleometrosis and secondary polygyny: a comparison of termites and ants
Authors: Roisin Yves
Published: November 2023

Highly organized and ecologically successful societies have evolved convergently in both termites and ants. These societies are characterized by large numbers of individuals and a great complexity with respect to social polymorphism, constructions, communications, foraging behaviour, etc. Perhaps the most important feature of these societies, from an evolutionary viewpoint, is the reproductive division of labour. In many ant and termite colonies, the egg-laying function is restricted to one or a few reproductive female(s), the queen(s). Polygyny, i.e. the coexistence of several functional queens in a colony, has considerable effects on intra-nest relatedness. Moreover, it generates conflicts of interests among these queens, in addition to possible conflicts between queens and non-reproductive individuals (workers, soldiers). Polygynous colonies are therefore of high interest for testing predictions derived from kin-selection theory.
The Snow Geese Of La Pérouse Bay
Authors: Cooke Fred , Lank David B , Rockwell Robert F
Published: November 2023

This book brings together the results from one of the most significant long-term studies of birds in the late twentieth century, testing our understanding of evolution in natural populations. Combining genetics, behavior, ecology, and a landmark data set, it will be essential reading for everyone with an interest in evolutionary ecology. The Lesser Snow Goose is a migratory Arctic breeder which occurs in two genetically distinct forms. Most have white plumage, but some are dark, allowing rapid scoring and study of a highly visible heritable trait. Initial chapters describe the natural history, recent evolutionary history, and current patterns of gene flow in the species. A subsequent chapter presents a detailed demographic model integrating both fecundity and survival components of fitness, which is used as an analytical framework throughout later chapters. Two chapters detail the effects of annual and age-specific variation in fitness components. The authors then focus on the micro evolutionary status of the population, using data gathered over 26 years on 40,000 individually marked adult geese, 45,000 nests, and 110,000 goslings at one colony in northern Manitoba. The heart of the book analyses the working of natural selection on plumage color, seasonal timing of breeding, clutch size, egg size, and body size, using the components of fitness approach to quantifying selection in stages throughout the animal life cycle. The results are an important advance in understanding the evolutionary process in vertebrates.
Insulin-like growth factor receptors
Authors: Moxham Cary , Jacobs Steven
Published: November 2023

Insulin and the insulin-like growth factors (IGFs) have an overlapping range of biological activities. Early competitive-binding studies demon strated that although IGF-I and -II bind weakly to insulin receptors, they have their own distinct, high-affinity receptors, and that there may be some heterogeneity amongst these receptors (Hintz et al. 1972; Marshal et al. 1974; Megyesi et al. 1974; Zapf et al. 1978; Rechler et al. 1980). Covalent affinity-labelling studies (Kasuga et al. 1981; Massague and Czech 1982) identified two, distinct, high-affinity IGF receptors with different structural features and binding properties. Type 1 receptors, which are structurally very similar to insulin receptors, are hormonally stimulated, tyrosine specific, protein kinases. They have highest affinity for IGF-1, a slightly lower affinity for IGF-II, and considerably lower affinity for insulin. It has become increasingly clear that the type 1 receptor mediates most of the well-known biological effects of both IGF-1 and -II. Type 2 receptors are structurally unrelated to insulin receptors. They have highest affinity for IGF-II, somewhat lower affinity for IGF-1, and do not appreciably bind insulin. The type 2 receptor has surprisingly been shown to have as its main physiological role the targeting of mannose-6-phosphate-containing enzymes to lysosomes. Its role, if any, in IGF-I- or -II-mediated, trans membrane signalling is very unclear.
Does change in clifferentiated cell phenotypes occur in normal development?
Authors: Okada T S
Published: November 2023

During their life history, somatic cells differentiate to attain their final phenotype. The a priori assumption is that they differentiate only once. There are, however, exceptions to this rule: (1) when organisms are exposed to pathological or other physiologically abnormal conditions; or (2) are subjected to some experimental intervention. Cells can sometimes propagate indefinitely, without expressing final differentiation phenotypes, although they can, perhaps, partially retain a potency of differentiation, as is well known in a number of neoplastic tumour cells. On the other hand, some cells can often express a ‘second’ phenotype during the life history of a cell lineage, usually in association with regenerative or reconstitutive processes, which will be discussed later. However, before a detailed discussion, this chapter will emphasize that there are several cell lines which differentiate twice (sometimes more) during their developmental history under normal conditions.
Factors influencing transdifferentiation
Authors: Okada T S
Published: November 2023

A number of extrinsic and intrinsic factors are known to influence the process of transdifferentiation in various ways. Different factors may act at different steps of the process, for example, triggering the change, facilitating a loss of pre-existing phenotypes, channelling the change along one of several different differentiation pathways, allowing the expression of new phenotypes, and others. There is little doubt that reviewing the role of these factors can provide clues to the mechanism of transdifferentiation in general. In this chapter, six major factors are discussed concerning their effect on transdifferentiation.
Nutritional Interactions In Symbiosis
Authors: Douglas A E
Published: November 2023

Nutritional interactions are fundamental to most symbioses, because the metabolic capabilities most commonly acquired through symbiosis relate to nutrition. With the exception of a few systems, e.g. luminescence symbioses in animals, the flow of nutrients from the donor to the recipient is substantial. However, the passage of nutrients is usually bidirectional (Fig. 4.1). Intracellular symbionts (which are invariably donors of novel metabolic capabilities) derive their entire nutritional requirement from the surrounding host cell, and many extracellular symbionts are also substantially dependent on host-derived nutrients.
The Ecological Impact Of Symbiosis
Authors: Douglas A E
Published: November 2023

Symbiosis is rarely considered in the ecological literature. There are two reasons (neither fully justified) for the neglect of this topic by ecologists. (a) Symbioses are often assumed to be mutualistic. When mutualistic interactions are modelled, the cooperating organisms proliferate uncontrollably, never reaching equilibrium (see review by Boucher 1985). This has led to the belief among some ecologists that symbioses are fundamentally unstable and prone to break down when exposed to environmental change or stress. In some ecological texts, symbioses are claimed to be restricted to supposedly stable environments in the tropics.
The palaeogeography of the opening South Atlantic
Authors: Parrish Judith Totman
Published: November 2023

The history of South Atlantic palaeogeography begins with the supercontinent, Pangaea. The assembly of Pangaea began with the middle Palaeozoic collision of north-western Europe with North America on the west and the Siberian platform on the east to form the continent called Laurussia. Shortly thereafter (geologically), Gondwana collided with Laurussia. The final assembly of Pangaea occurred in the Early Triassic with the collision between North and South China that raised the Chinling Range (J. M. Parrish et al. 1986). No sooner had Pangaea come together than it began breaking up. Continental deposits associated with the initial rift valleys in eastern North America are Triassic in age. The Central Atlantic opened first between north-western Africa and south-eastern North America. Because South America and Africa were still one plate, the opening of the Central Atlantic caused relative motion between North and South America; the Gulf of Mexico and eventually the Caribbean formed in the intervening space. The opening of the South Atlantic began in the Early Cretaceous. The final plate separation in the circum-Atlantic region was between North America and north-western Europe. The central focus of this book is the history of connections between Africa and South America, and so the history of the South Atlantic forms the principal focus of this chapter. However, connections between North and South America and Africa and Europe (and thus North America) are also discussed.
‘Grube Messel’ and African–South American faunal connections
Authors: Storch Gerhard
Published: November 2023

The fossil record of the European Early Tertiary includes various terrestrial vertebrates which are most unexpected and of an ‘exotic’ appearance palaeobiogeographically. Outside Europe, they are known in the late Cretaceous and the Cenozoic of West Gondwanaland, in particular of South America, but they are unknown in the Late Cretaceous and the Early Tertiary of North America. The presence of these vertebrates thus suggests former land connections between Africa and South America and a crossing of the marine Tethys barrier between Africa and Europe by terrestrial routes. European palaeofaunas might, therefore, contribute to an understanding of African-South American faunal relationships. These groups are: ceratophryine anurans (Rage 1981), ziphodont mesosuchian crocodiles (Buffetaut 1988), struthioniform birds (ratites) (Houde 1986; Peters 1988a), phorusrhacid birds (Mourer-Chauvire 1981; Peters 1987), and myrmecophagid edentates (anteaters) (Storch 1981). Cariamid birds (seriemas) (Mourer-Chauvire 1983; Peters 1988b, and didelphid marsupials can be added (Crochet and Sige 1983; Von Koenigswald and Storch 1988), but unlike the preceding taxa they are also known as Early Tertiary fossils in North America.
Feeding with other Oystercatchers
Authors: Ens Bruno J , Cayford John T
Published: November 2023

Because Oystercatchers are conspicuous and feed on easily identifiable prey items in an open habitat, they are an ideal species for studying the two competitive processes among foraging predators of prey depletion and mutual interference. This chapter reviews studies of mutual interference, defined as the more or less immediate and reversible reduction in intake rate at high densities of conspecifics (Goss-Custard 1980); the effects of depletion are considered elsewhere (Goss-Custard et al., Chapter 6, this volume). Early theoretical work (e.g. Hassell 1978), as well as empirical studies on shorebirds (Goss-Custard 1970; Zwarts 1978; Zwarts and Drent 1981), did not explicitly address differences between individuals. But field studies of marked birds revealed that individuals did not suffer equally from an increase in bird density.
Population dynamics: predicting the consequences of habitat change at the continental scale
Authors: Goss-Custard John D , Durell Sarah le V dit , Clarke Ralph T , Beintema Albert , Caldow Richard W G , Meininger Peter L , Smit Cor J
Published: November 2023

As the previous chapter discussed, Oystercarcher numbers breeding or wintering in one area may depend not only on factors operating in that area hut also on the supply of birds available to live there. This, in turn, depends on the attractiveness of the area relative to others and on processes occurring on the, often distant, wintering or breeding grounds and on migration. In such a species, population processes must be investigated at large spatial scales. But how large must the scale be before, in some meaningful sense, we can say that a population is being studied? Oystercatcher numbers on one mussel bed, for example, are determined almost entirely by the behavioural decisions of individuals and few would regard investigating this as a population study. But as the scale increases relative to the scale of movement of individuals, numbers become increasingly dominated by the balance between reproductive and mortality rates until all of the important changes in numbers are caused this way. Some ecologists argue that population studies can only be done satisfactorily at the scale at which immigration and emigration arc for all practical purposes non-existent.
Skeletal and other basic anatomical features of elephants
Authors: Shoshani Jeheskel
Published: November 2023

The purpose of this chapter is to augment the dental terminology (Tassy, this volume, Chapter 3) and ontogenetic data on incisors (Luckett, this volume, Chapter 4), and to provide brief but basic information on the anatomical (excluding functional) features found in elephants, so that non-proboscideanologists can be introduced to elephant anatomy. Living representatives of Proboscidea, Loxodonta africana (the African elephant) and Elephas maximus (the Asian elephant), were used as models for hard and soft anatomies (Fig. 2.1).
The earliest gomphotheres
Authors: Tassy Pascal
Published: November 2023

The name ‘gomphotheres’ is used here in a restrictive sense; it is not entirely synonymous with the ‘bunodont mastodonts’ (sensu Tobien 1973a) or the family name Gomphotheriidae Hay, 1922, based on the genus Gomphotherium Burmeister, 1837. Rather, the term gomphotheres, is used here to refer to the stem-group of both stegodontids and elephants, and thus designates a paraphyletic group (Tassy 1988a). Taxa included in the gomphotheres share bunodont teeth, a cranium with a transversely enlarged nasal aperture (however, see footnote 2, p. 45), and lower tusks with a piriform to oval, or even round cross-section. Hence, the gomphotheres, as defined here, do not include mammutids (zygodont teeth), nor the genus Choerolophodon Schlesinger, 1917 (with bunodont teeth but a narrow nasal aperture), and the amebelodontids (with bunodont teeth and a large nasal aperture but lower tusks with flat cross-section). Mammutids, choerolophodons, and amebe lodons are considered as earlier offshoots of the Elephantoidea.
Phylogeny of African and Eurasian Elephantoidea of the late Neogene
Authors: Kalb Jon E , Froehlich David J , Bell Gorden L
Published: November 2023

It has been nearly 200 years since Johann Blumenbach gave us the first systematic description of an African proboscidean, a right lower second molar, which in 179 7 he referred to as ‘Elephas africanus’ (Osborn 1942, pp. 1192, 1197). In 1825, Etienne Geoffroy Saint-Hilaire and Frederic Cuvier published their classic work, Histoire Naturelle des Mammiferes, in which they created a new genus, ‘Loxodonte’, for this ‘elephant d’Afrique’, based on the unique lozenge-shaped enamel on the plates of its molars. Two years later, in 182 7, an article appeared in the Zoological Journal of London by an anonymous writer who referred to this redesignation of names for ‘Loxodonta africanus’ as the ‘dismemberment of the genus Elephas’ (Anonymous, 1827, p. 140; see also Damning and Shoshani, 1982). Ever since, palaeontologists have been describing, redescribing, and ‘dismembering’ African proboscideans.
Evolution and taxonomy of Eurasian mammoths
Authors: Lister Adrian M
Published: November 2023

Mammoths (genus Mammuthus) first appeared in continental Eurasia in the late Pliocene, about 2.5 Ma, and persisted until the end of the Pleistocene, around 10 000 years BP. Samples of mammoth fossils through the Eurasian Plio-Pleistocene show a series of anatomical trends, including changes in body size, heightening of the cranium and molar teeth, shortening of the cranium and mandible, thinning of molar enamel, and increase in the number of lamellae (enamel plates). These trends have long been known from studies of typical samples of the three main nominal chronospecies of the lineage: early Pleistocene Mammuthus meridionalis (Nesti), middle Pleistocene M. trogontheril (Pohlig), and late Pleistocene M. primigenius (Blumenbach) (Soergel 1912; Aguirre 1968, 1969b; Maglio 1973; here Fig. 19.1). New material and improved dating techniques now allow many more samples to be placed in chronological order and the evolutionary sequence examined in more detail. Further details of many of the topics summarized in this paper will be given elsewhere.
The proboscideans of the South-East Asian islands
Authors: Bergh Gert D Van Den , Sondaar Paul Y , Vos, John De , Aziz Fachroel
Published: November 2023

Present-day elephants are excellent swimmers Gohnson 1978). The presence of Pleistocene fossil proboscidean remains on several islands surrounded by deep seas suggests that, in the past, proboscideans had a relatively high potential to cross sea barriers. It is not uncommon to find proboscideans in a fossil assemblage of impoverished endemic island faunas, sometimes as the only large mammal. In the Lesser Sunda Arc, Indonesia (Fig. 23.1), only Stegodontidae have been reported as large mammals on the islands Flores, Sumba, and Timor.
Diseases and parasites
Authors: Pratt H Douglas , Jeffrey Jack , Conant Sheila
Published: November 2023

In a typical life history account of a bird species, or in books like this one, a few perfunctory lines are usually included to indicate that the species or group in question is known to have certain diseases and parasites. Such information is included for completeness, but is frequently ignored by readers who prefer to concentrate on more important or more interesting subjects such as ecology and behaviour. Unfortunately, no one can ignore disease in any discussion of Hawaiian honeycreepers. Indeed, for the past two centuries, disease has probably been the single most important factor in drepanidine natural history, directly causing the extinction of many species, contributing to the demise of others, and determining the present-day distributions of survivors.
Genus Melamprosops
Authors: Pratt H Douglas , Jeffrey Jack , Conant Sheila
Published: November 2023

Medium-sized, stocky, short-tailed birds with short, heavy, somewhat finchlike bills. Interorbital septum weak and sometimes fenestrated (James and Olson 1991). Tongue non-tubular, with rounded spoon-like tip (Bock 1978) and prominent lingual wings, unlike the truncate proximal end of most drepanidine tongues (Pratt 1992b). Food includes terrestrial molluscs and other invertebrates gleaned from trunks and branches of trees (Baldwin and Casey 1983;T. K. Pratt et al. 1997). Plumage colours atypical among honeycreepers, mostly brown above, buffy white below, with prominent black facial mask.
The relation of silviculture to forest management
Authors: Matthews John D
Published: November 2023

The complexity of modern forestry has stimulated publication of separate detailed accounts of silviculture and forest management, but Kniichel (1953), Dubordieu (1986b), Levack (1986), and many other authors have demonstrated the need to fuse the concepts of silviculture and management closely together. The purpose of this chapter is to summarize and comment on several topics which are treated in textbooks on forest management (see for example Johnston et al. 1967; Davis and Johnson 1987) from the viewpoint of silvicultural systems.
The selection system
Authors: Matthews John D
Published: November 2023

The selection system differs from all the other silvicultural systems in that felling and regeneration are not confined to certain parts of the forest but are distributed all over it, the fellings removing single trees or small groups of trees selected throughout the forest. Fellings done in this manner are termed selection fellings; they result in an uneven-aged or irregular type of forest in which all the age or size classes are mixed together over every part of the area. This completely uneven-aged type of forest is usually termed ‘selection forest’ or ‘forest of selection type’, whether it has actually been produced by selection fellings or not. Under the selection system, scattered single trees or small groups of trees are selected over the whole area and removed. Where conditions are favourable, natural regeneration springs up in the gaps so created. Under ideal conditions this process goes on year after year over the whole forest, the volume removed being fixed by rules of management (page 54). This results in the constant maintenance throughout the whole area of an uneven-aged or irregular structure in which trees of all ages are mixed together. Such perfect distribution is seldom actually found, the age-classes occurring more usually in small groups resulting from groups of regeneration springing up in gaps. The appearance of forest worked under the selection system is shown in Figs. 26 and 27.
Agro-forestry systems
Authors: Matthews John D
Published: November 2023

The practice of growing timber trees, fruit trees, shrubs, and palms in combination with agricultural crops and animals is very widespread and takes many forms. Forestry may be combined with agriculture to improve the microclimate for field crops and animals, maintain soil fertility, control erosion, produce fuelwood and timber, and increase the cash income from the land. In 1978 the International Council for Research in Agro-forestry (ICRAF), sponsored by Canada, Holland, and Switzerland set up its headquarters in Kenya ‘to improve the nutritional, economic, and social well-being of developing countries by the promotion of agro-forestry systems designed to result in better land use without detriment to the environment’ (ICRAF 1983). ICRAF has made an inventory of existing practices and systems around the world. The classification recognizes agro-silvicultural systems in which agricultural crops are grown with trees; silvo-pastoral systems where the trees provide fodder and shaded pasture for grazing animals; agro silvopastoral systems which combine all three; and ‘home gardens’ such as those in the humid parts of southern Asia which have many-storied mixtures of trees, shrubs, and other plants, akin to the structure of tropical moist forest on a very small scale.
Jurassic
Authors: Shunbao Wu , Jinnan Tong
Published: November 2023

The plate tectonic history of the Jurassic is characterized by the disintegration of Gondwana and the initiation of the three main modem oceans. Another aspect of the Jurassic is its higher and more evenly distributed palaeotemperature than in modem times. The Jurassic palaeobiogeographic provincialization of the world is suggested as follows (Fig. 10.1, Table 10.1).
The geotechnical and geochemical implications of bioturbation in marine sedimentary ecosystems
Authors: Meadows Peter S , Meadows Azra
Published: November 2023

Bioturbation occurs to different degrees in all marine sedimentary ecosystems. It is most obvious in estuarine and inshore environments but also occurs in deep-sea sediments at a reduced level. The fossil record also has many examples of bioturbation structures in a wide range of sedimentary rocks from different geological ages (cf. Bromley 1990). The disturbance caused by burrowing animals can be very shallow-a matter of a few centimetres―or may extend to more than 3 m. Burrow size ranges from less than 1 mm in diameter to about 10 cm. Some animals transport sediment vertically and horizontally while others anchor themselves by threads or move through the sediment. The effects of bioturbation are therefore diverse and likely to be of great importance in civil engineering and the oil industry.
The environmental impact of burrows and burrowing animals-conclusions and a model
Authors: Meadows Peter s.
Published: November 2023

The papers presented in the symposium are briefly reviewed and their different approaches contrasted to provide an overall picture of the environmental impact of burrowing animals and burrow systems. Simple models are then developed that define indices of burrow system complexity and tortuosity and of the activity of animals and effects of burrows on the environment. It lS hoped that these indices will provide a unified methodology for assessing the impact of burrowing animals and their burrows on both aquatic and terrestrial ecosytems.
Other Botanical Gardens
Authors: Desmond Ray
Published: November 2023

By the end of the Victorian era many towns in British India boasted public parks and gardens administered by the municipal authority and often managed by gardeners trained at the Royal Botanic Gardens at Kew. Agri-horticultural societies also maintained private gardens for the use of their members. Some of these gardens purported to be ‘botanical’ but there were only four establishments in South Asia which strictly justified the epithet: Calcutta, Saharanpur, and Ootacamund in India, and Peradeniya in Ceylon.
Retinoic acid receptors
Authors: Leroy Pierre , Krust Andrée , Kastner Philippe , Mendelsohn Cathy , Zelent Arthur , Chambon Pierre
Published: November 2023

The establishment of anatomical structures of the embryo throughout its development is thought to be controlled by morphogenctic molecules, which would instruct the cells of the three germ layers to differentiate according to their position with respect to organizing region(s) (Slack 1987a; Wolpert 1989; Summerbell and Maden 1990). Retinoic acid (RA) is generally believed to be a natural morphogen (Maden 1982; Tickle et al. 1982; Slack 1987h; Thaller and Eichele 1987; Smith et al. 1989; Eichele 1990), and plays an important role in the development and homeostasis of vertebrates (Chytil 1984; Maden 1985; Brockes 1989, 1990; Eichele 1989a,b; Durston et al. 1989; Sive et al. 1990; Wagner et al. 1900; Ruiz i Altaba and Jessel 1991; and references therein). However, recent reports raised a controversy by questioning the role of RA as a true morphogenetic signal (Brockes 1991; Wanek et al. 1991; Noji et al. 1991). The multiple effects exerted by RA on cultured cells or during development and in the adult, have often been correlated with changes in the expression patterns of specific genes (Wang and Gudas 1983; La Rosa and Gudas 1988; Murphy et al. 1988; Lüscher et al. 1989; Vasios et al. 1989; Chytil and Haq 1990; Okamoto et al. 1990; Simeone et al. 1990; Wang et al. 1990; Nicholson et al. 1990; Dinsmore and Solomon, 1991; and references therein). These observations suggest that RA may directly modulate gene expression through an RA-responsive machinery, which would ultimately interpret the putative morphogenetic signal provided by RA. The fine dissection of this “molecular machinery” is a prerequisite to a better understanding of RA-triggered positional signalling (see lzpisúa-Belmonte et al. 1991, for a discussion of this point).
Molecular mechanisms of retinoic acid action
Authors: Pfahl Magnus , Zhang Xiao-Kun , Lehmann Jürgen M , Husmann Matthias , Graupner Gerhart , Hoffmann Birgit
Published: November 2023

The multitude of essential biological processes regulated by the vitamin A derivative retinoic acid (RA) and synthetic analogues (retinoids) (reviewed in Lotan 1980; Sporn et al. 1984), combined with the many beneficial and undesirable side-effects (Lippman et al. 1987) associated with retinoid therapies, suggest the existence of a highly complex regulatory mechanism. How can a single substance —RA—regulate a large diversity of programmes and, in addition, provoke at times opposite effects, e.g. during limb morphogenesis, where low concentrations of RA can lead to duplications of digits, while high concentrations prevent digit formation (Tickle et al. 1982; Summerbell 1983). The discovery of nuclear retinoic acid receptors (RAR) that belong to the steroid-thyroid hormone receptor family represented a breakthrough towards the elucidation of a molecular mechanism of RA action (Petkovich et al. 1987; Giguère et al. 1987). These receptor proteins are ligand-dependent transcription factors that contain a highly conserved “zinc-finger” DNA binding domain and a less conserved hydrophobic ligand binding domain (Evans 1988; Green and Chambon 1988). The receptors modulate gene transcription by interacting with specific DNA sequences the responsive elements that are frequently located near the promoters of susceptible genes (Beato 1989).
Retinoic acid receptors in the chick embryo
Authors: Rowe Annie , Eager Nicholas S C , Richman Joy M , Brickell Paul M
Published: November 2023

The chicken is of particular value as an organism for studies of vertebrate embryonic development because chick embryos can be manipulated in ovo and the effects of such manipulations on their further development can be examined. Such studies have contributed a great deal to our view of the possible role of retinoids in vertebrate embryonic development. This is largely a result of experiments showing that the local application of all-trans-retinoic acid to the anterior margin of the chick wing bud results in the development of wings in which the pattern of the digits and other skeletal elements is altered. This behaviour mimics that of the polarizing region, a group of cells at the posterior margin of the limb bud that are involved in patterning the normal limb, and there is evidence that retinoids may be natural signalling substances in chick limb buds (reviewed by Tickle and Brickell 1991). For these reasons, we and others have analysed the chicken’s system of retinoic acid (RA) nuclear receptors. The purpose of this article is to review what is known about this system and then to concentrate on our own recent studies of the chicken R×R and RAR-β nuclear receptors.