bluuebunny/crossref_metadata_2025 huggingface dataset:
Semantics
Authors: Hankin Chris
Published: November 2023

We now make a brief excursion into the model theory of the A-calculus. We start by abstracting the common properties of models. A detailed study would quickly take us into the realms of domain theory and out of the scope of this book. However, to make the material more concrete, we do consider two model constructions. The first is the term models. We also introduce Bohm trees and show how a model can be constructed from them. The purpose of a model is to give a semantics for terms. The objective is to identify each term with an element of some mathematical structure, normally a set or a set with additional structure (e.g. a complete partial order); the underlying theory of the mathematical structure then becomes available as a basis for reasoning about the terms of our language and their inter-relationships.
Other Calculi
Authors: Hankin Chris
Published: November 2023

In this chapter we present three other calculi which have been proposed in the last few years. Each addresses a different deficiency of the pure calculus that has been our main object of study. This chapter is slightly different in style compared to the earlier chapters; we cover a lot of material with few examples or exercises. We have chosen to emphasise the proof theory of the calculi - the interested reader is urged to consult the original source material for details of models and more motivational examples.
Learning Perceptually Chunked Macro Operators
Authors: Suwa M , Motoda H
Published: November 2023

In previous studies search control knowledge has been acquired using explanation-based learning (EBL) techniques. These learn goal-oriented control knowledge by explaining how a decision at a control decision node leads to the goal. In the domain of geometry problem-solving, however, this leads to knowledge which is neither sufficiently general nor sufficiently operational. This paper addresses an alternative form of search control knowledge in which the search is controlled at each decision node in such a way that a problem solver can locally recognize relevant ‘perceptual chunks’. Previously the effectiveness of perceptual chunks as control knowledge has been reported in a geometry domain. In this paper, we propose a new chunking technique, which acquires, as a chunk, an assembly of diagram elements that can be recognized and grouped together with the control decision node. In order to implement this chunking criterion a learner, Pclearn, employs recognition rules, domain specific knowledge describing necessary conditions for a domain object to be recognizable. Experiments in a geometry domain show that the set of learned knowledge exhibits higher operationality than EBL macro-operators. They also suggest that the Pclearn chunking technique can be a powerful method for obtaining a small and highly organized set of domain-specific perceptual chunks if augmented with a mechanism for dynamically managing the utility of each chunk.
Deriving Qualitative Control for Dynamic Systems
Authors: Bratko Ivan
Published: November 2023

This paper investigates how qualitative reasoning can be applied to deriving control rules for dynamic systems. The balancing of pole and cart is used as an example problem. A qualitative control rule is derived from a qualitative model of the pole-andcart system. This rule is shown to be a qualitative abstraction of the ‘classical’ control rule derived from the differential equations model of this system.
Efficient algorithms for inductive learning – an application of multi-linear functions to inductive learning
Authors: Tsukimoto Hiroshi , Morita Chie
Published: November 2023

Although many algorithms have been presented for empirical inductive learning, there are few algorithms whose sample complexity and computational complexity have been theoretically analysed. Moreover, although many algorithms have been presented in computational learning theory, few algorithms can be applied to empirical inductive learning problems. Our final target is to present efficient algorithms for attribute-based inductive learning, whose sample complexity and computational complexity lend themselves to theoretical analysis. This paper presents efficient algorithms for attribute-based inductive learning.
Adapting Good’s Q theory to the causation of individual events
Authors: Michie Donald
Published: November 2023

The notion of causality is embedded in scientific language. I. J. Good’s ‘Qsuf’ for sufficient causation and ‘Qnec’ for necessary causation satisfactorily formalize the general idea of causal tendency in an additive framework of Bayesian weights of evidence. But there remain difficulties in characterizing the causes of individual events. In this paper Good’s theory is combined with an explicit treatment of individual events as sets, and is specialized to the management by resource-bounded agents of causal belief, both about tendencies and about individual events. The approach is strictly statistical and treats cause as a degree of rational inferrability, without commitment to whether or not causality is a physical law, i.e. an objective property of external reality.
Tables, graphs and logic for induction
Authors: Yoshida Kenichi , Motoda Hiroshi
Published: November 2023

Inductive learning, which tries to find rules from data, has been an important area of investigation. One major research theme of this area is the data representation language that the learning methods can use. Conventional learning methods use attributevalue tables as the data representation language, whereas inductive logic programming (ILP) uses first-order logic. We propose colored directed graphs as a data representation language for inductive learning methods. Graph-based induction (GBI) uses this data representation language. The expressiveness of graphs is in between the attributevalue table and the first-order logic. Thus its learning potential is weaker than that of ILP, but stronger than that of conventional attribute-value learning methods. The real advantage of GBI appears in the domain where the dependency between data bears the essential information.
The British Tabulating Machine Company, 1907-1919
Authors: Martin Campbell-Kelly
Published: November 2023

The period from 1907 up to the end of the First World War saw BTM grow from a very small business, employing a handful of people importing a few machines from the United States, to a medium-sized business with some manufacturing facilities and employing in the region of a hundred people. Probably the best measure of BTM’s progress are its assets and number of personnel (Table 2.1). The assets represented both conventional fixed assets (buildings and machinery), and also a constantly increasing proportion of tabulating machinery on hire. BTM’s growth can be seen as taking place in three phases. First, the period 1907-1911 saw the company tackling the two main problems of entering the office-machinery market: the slow acceptance of office machines in Britain, and the need to raise capital for leasing. The second phase of company growth began with its securing a contract to supply tabulating machines for the British census of 1911. This contract transformed the business outlook of the company, and during the remaining years leading up to the First World War the customer base built up to about thirty installations.
Manufacturing at home, the 1920s
Authors: Martin Campbell-Kelly
Published: November 2023

Both BTM and the Ace and Tab began the 1920s by starting up manufacturing operations in the UK: this was a crucial step in the process of becoming manufacturers, instead of mere importers, of office machines. The British punched-card machine manufacturers were representative of many companies which sprang into prominence during the rise of the office-appliance trades in the 1920s; this chapter examines BTM and the Ace and Tab in their national and international context in the officemachine industry.
Electronic machines, 1950-1954
Authors: Martin Campbell-Kelly
Published: November 2023

Two themes dominate the history of the British punched-card machine industry during the early 1950s: independence from the American companies, and electronic developments.

The main consequences of independence were that the companies were exposed to competition from IBM, and that they were now entirely responsible for generating their own R&D. The companies had a breathing space of perhaps two or three years to come to terms with the new conditions, an adjustment which was made all the more painful by the fact that the post-war seller's market had come to an end. The early 1950s also saw the beginning of the transition from punched-card machines to electronic computers, a transition that was not completed until the middle of the 1960s. Although it was not fully realized at the time, R&D in electronics was the key to the future.
Computers and the merger, 1955-1958
Authors: Martin Campbell-Kelly
Published: November 2023

By about 1955 BTM and Powers-Samas began to feel for the first time the full force of the competition from IBM, and for both of them it, rather than the other British company, was now the most serious competitor. To become international business-machine companies capable of competing with IBM, the British punched-card machine companies had three strategic objectives: first, to expand in order to sustain their market share; second, to improve their traditional punched-card products; and third, to make an effective entry into the computer market.
The decline of the tabulator, 1959-1961
Authors: Martin Campbell-Kelly
Published: November 2023

As a company, ICT existed for about eight years, before finally merging with English Electric Computers Limited to form ICL in 1968. Although ICT’s revenues grew at an overall rate of 15 per cent a year during this period (Table 9.1), this fell far short of the 30 per cent annual growth rate hoped for when ICT began operations. There was also considerable volatility from year to year, and profits generally failed to keep pace with revenue growth-both in absolute terms and as a return on funds employed. The company’s head count also tended to rise and fall with these financial vicissitudes.
Negotiations and mergers, 1961-1963
Authors: Martin Campbell-Kelly
Published: November 2023

During 1961-63, ICT was involved in an almost constant round of negotiations with virtually every major computer company in America and Britain, as well as Machines Bull in France. The threads of this tapestry of negotiation are very difficult to untangle. For example, ICT and Machines Bull were both independently talking to RCA and General Electric in the United States, at the same time as they were talking to each other; and simultaneously ICT, English Electric, and RCA were considering some tripartite agreement. There were thus at least six separate, but interlocking, sets of negotiations involving just these companies. The course of these negotiations becomes much clearer when viewed in the context of ICT’s objective in seeking liaisons with other companies. ICT’s objective was to strengthen its position in computers in two ways. First, it needed to close the technology gap between its own computers and those available in the United States-this implied a close relationship with an American company. Second, it needed to increase its electronic production facilities-this implied either merging with, or acquiring, another British computer company.
Convergence, the 1980s
Authors: Martin Campbell-Kelly
Published: November 2023

In 1980, ICL and all the other mainframe manufacturers were faced with two major challenges, one short-term and one medium-term. The shortterm problem was to come to terms with the lower profit margins caused by the price-war between IBM and the Japanese plug-compatible mainframe manufacturers. The medium-term problem was to respond to the coming convergence of computers and communications: this convergence implied not merely developing networked computer systems, but also achieving strategic alliances or mergers with telecommunications firms. In the United States, following de-regulation of the telecommunications industry, new competitors such as AT&T had begun to offer computer and information services, and several computer companies had already made alliances with communications suppliers. Before ICL could respond to these larger issues, however, it had to deal with its short-term problems.
The nature of computer viruses
Authors: Louw Eric , Duffy Neil
Published: November 2023

Some confusion about what qualifies as a computer virus is evident in much of the literature. Many writers use the term very loosely and fail to distinguish viruses from other types of malicious program. or even accidental software ‘bugs’. Although a great deal of what is said about viruses also holds true for other types of ‘electronic pest’; namely Trojan horses, bombs, and worms, the differences between them are important enough to demand that they be distinguished from one another. Other writers use two or three terms to describe what is essentially the same thing. We will try to clear up this confusion by defining carefully what we mean by the terms ‘computer virus’, ‘bomb’, ‘Trojan horse’, ‘worm’, and ‘bug’. The first generally accepted definition was provided by Cohen who defined a computer virus as a program able to ‘infect’ other programs by modifying them to include a possibly evolved version of itself. While this is an acceptable and concise definition of a virus. its implications may not be immediately apparent.
Protection against computer viruses
Authors: Louw Eric , Duffy Neil
Published: November 2023

All the evidence indicates that computer viruses can be designed to disrupt virtually any type of system, PC or mainframe. Campbell believes that: ‘Neither the technology nor the tools now available can ensure the integrity of any system’. One of the objectives of this book is to develop a framework for dealing with computer viruses in business organizations. To this end, this chapter commences with a short discussion of computer security, in which key concepts are introduced and a framework for IS security and control is presented. The framework for dealing with computer viruses will be based on the structure of this general security framework. We lay the foundation for the virus control framework with a discussion of computer viruses as a security issue. The remainder of the chapter discusses the individual elements of the IS security and control framework as they apply to computer viruses. A methodology, model, or checklist is distilled from each discussion.
Preliminaries
Authors: Hahnle Reiner
Published: November 2023

In this chapter we collect some definitions that we will use frequently in this book and introduce some special notation. Readers who are familiar with formal logic and automated theorem proving can skip this chapter in a first reading.
The Logical Basis: Signed Analytic Tableaux
Authors: Hahnle Reiner
Published: November 2023

The formal proof system called semantic (or analytic) tableaux was introduced by E. W. Beth (1986) and K. J. J. Hintikka (1955) in the 1950s, its ancestors being Gentzen systems. R. Smullyan (1968) gave a particularly elegant version of tableaux which largely increased their popularity, and most tableaux systems used today are based on the formulation he set out. Semantic tableaux are popular as a pedagogical tool; however, recently, their importance in the field of automated theorem proving has also grown substantially.
Beyond Tableaux
Authors: Hahnle Reiner
Published: November 2023

In this chapter we go beyond the particular framework of semantic tableaux and show that the main concepts developed so far, such as sets-as-signs, regular signs, and connectives can also be used in the context of other inference procedures which are potentially more efficient than are pure tableaux.
Life history of the Appendicularia
Authors: Fenaux R
Published: November 2023

The first serious attempt to study appendicularian development was that of Delsman (1911, 1912), which still remains the only description of cleavage and embryonic development. The chronology of development in cultured Oikopleura dioica was given by Galt (1972), Paffenhofer (1973) and Fenaux (1976). Fenaux and Gorsky (1983) decribed the development and growth of O.longi.cauda, the only hermaphroditic oikopleurid to be cultured so far; they found a similar general pattern with a few differences in detail. Most of the information given here concerns O.dioica. A comprehensive review of the reproductive biology of appendicularians can be found in Galt and Fenaux (1990b).
Islands, regions, ranges, and gradients
Authors: Dennis Roger L H
Published: November 2023

Butterflies are conspicuous insects. Because of this and because there are fewer species of butterflies than in other groups of insects, they are usually eas¬ily recognized and their distributions for the most part well known. This book starts, then, by asking a basic but most important biogeographical question: why do different butterfly species occur where they do but not everywhere? The full answer is rarely simple. Essentially, distribution patterns depend on at least three factors: (i) the behavioural and ecologi¬cal requirements of the species, (ii) the geographical extent of the appropriate environmental conditions and resources, and (iii) the historical opportunity for organisms to colonize new areas. The degree to which butterflies are influenced by different factors depends greatly on the scale at which observations are made, though scale interdependence ensures that what happens at one scale cannot be entirely separated, in terms of cause and effect, from another. Local, regional, and continental patterns are linked in numerous ways. In this chapter, an array of problems concerning distributions is investigated at a wide range of scales, from the British islands as a whole to issues amid local settings.
Butterfly populations
Authors: Warren Martin S
Published: November 2023

In an ecological context, the word ‘population’ has a more precise meaning than it has acquired in common usage, and needs to be defined to avoid confusion. Throughout this book, the term ‘popula¬tion’ refers to a group of individuals of a particular species that are separated to some extent, either in space or in time, from other groups of the same species. Each group, or population, usually occupies a discrete site or region and is separated from other groups by an area which is generally uninhabited. Thus, a species of butterfly occurring on chalk downland may be separated into two distinct populations by an intervening belt of scrub, or by some other unsuitable type of vegetation.
Introduction
Authors: Møller Anders Pape , Gregersen Jens
Published: November 2023

When Darwin published On the origin of species by means of natural selection in 1859 he was basically able to account for the evolution of apparently adaptive characters and the process of speciation by means of natural selection. Variation in characters between individuals (which later became known as phenotypic variation), resource limitation, and the resulting non-random association between the expression of characters and a com¬ ponent of fitness were supposed to give rise to changes in the average character value. With the work of Mendel it was established that there was an association between phenotype and genotype, and differential fitness among phenotypes resulted in micro-evolutionary changes in gene frequencies.
Male mating advantages
Authors: Møller Anders Pape , Gregersen Jens
Published: November 2023

The primary driving force in sexual selection is non-random variation in mating success. For example, males with the most extreme secondary sexual characters may enjoy a mating advantage that results in an association between the expression of a sex trait and a fitness component. However, it is usually forgotten that sexual selection may take place at a number of different stages of the reproductive cycle, and that mating success is but one selection component, perhaps not even the most important one. The several components of sexual selection are briefly reviewed in section 4.2.

In section 4.3 of this chapter I summarize the evidence for the action of different sexual selection components in the barn swallow. More specifically, I describe the relationship between the tail length of males and:
Paternal care and male ornamentation
Authors: Møller Anders Pape , Gregersen Jens
Published: November 2023

Measurement of indirect fitness benefits through sexual selection are simplified in the absence of obvious direct fitness benefits such as parental care (see Chapter 2). Analysis of the relative contribution of direct and indirect fitness benefits through mate choice quickly becomes difficult when both components are present. The expression of a secondary sexual character may reflect indirect fitness benefits such as male attractiveness or superior genetic constitution, but the extent of paternal care may also be reflected in the expression of a male sex trait. Therefore, the problem is to determine whether the expression of the secondary sex trait reflects direct or indirect fitness benefits to the female.
Sexual size dimorphism and female ornaments
Authors: Møller Anders Pape , Gregersen Jens
Published: November 2023

In many animal species males differ in size from females. For example, females are considerably larger than males in many invertebrates, fish, amphibians, and reptiles, whereas males are larger than females in most birds and mammals (Darwin 1871 ). Why is this the case? Size differences between the two sexes are most readily explained by selection processes affecting individuals differently (section 12.2). Sexual size dimorphism may result from natural or sexual selection, as already emphasized by Charles Darwin (1871). Natural selection will affect the morphology of males and females both during reproduction and the non-reproductive period. For example, males and females may have slightly different foraging behaviour and habitat choice, and the different natural selection pressures under two kinds of environmental conditions may result in sexual differences in morphology. Intersexual competition for food resources may thus lead to sexual size dimorphism due to natural selection acting on heritable variation in morphology.
The evolution of polygyny in primitively eusocial polistine wasps with special reference to the genus ropalidia
Authors: Itô Yosiaki
Published: November 2023

The eusocial Vespidae can be divided into two broad categories, the primitively eusocial and the highly eusocial. Primitively eusocial species lack morphologically distinct queens. Although their ‘queens’ (inseminated and overwintered females in temperate species and major egg-layers in tropical species) are often larger than ‘workers’, their sizes overlap and workers have opportunities for personal reproduction (Ross and Matthews 1991). On the other hand, queens of highly eusocial species are distinguishable morphologically from workers, and the latter, as a rule, cannot lay diploid, female eggs. Most species of the subfamily Vespinae are highly eusocial (Matsuura 1991), all known species of the subfamily Stenogastrinae are primitively eusocial (Turillazzi 1991), while the subfamily Polistinae contains both primitively and highly eusocial species (Jeanne 1991; Gadagkar 1991; Reeve 1991). Within the Polistinae, we can distinguish two subgroups, the independent-founding species, in which colonies are initiated by one or several inseminated foundresses (queens), independently of any uninseminated females (workers), and the swarm-founding species, in which a colony is founded by a swarm containing a small number of queens and a large number of workers (Jeanne 1980).
Annual Variation In Fitness Components
Authors: Lank David B
Published: November 2023

Long term studies allow examination of a population’s response to a range of naturally occurring environmental conditions. Fluctuation in selective regime, on an appropriate time scale, is a potential mechanism for maintaining genetic variation in a population. The work at La Perouse Bay began in 1968, providing up to 25 breeding seasons’ data with which to assess the selective regime and the birds’ values for various components of fitness. We can determine whether patterns are relatively robust or highly sensitive to environmental conditions, and ascribe some of the total variation in characteristics to environmental or other variables acting on the population. We first outline the major factors which vary among seasons, then present data on the annual variability of fitness components and attempt to correlate this variation with one or more of these factors.
Age effects
Authors: Lank David B , Rockwell Robert F
Published: November 2023

A population’s potential ecological and evolutionary dynamics are determined in large measure by its life history strategy. By strategy, we mean those ‘coadapted traits designed, by natural selection, to solve particular ecological problems’ (Stearns 1976). A life-history strategy includes age-specific schedules of breeding propensity, reproductive success and survivorship. Combined, these parameters determine the lifetime reproductive success of individuals. This chapter describes the age-specific patterns of the fitness components for the Lesser Snow Goose, and considers the implications of these patterns on the ecology of the species.
Clutch size
Authors: Lank David B
Published: November 2023

This chapter considers clutch size, one of the most obvious and easily measured components of fitness. We determine the selection gradient on this univariate phenotypic trait (Arnold and Wade 1984b), and consider its ecological and evolutionary constraints and consequences. Thus, we assess whether and how other fitness components and net fitness vary with respect to clutch size.
Fish as prey: numbers, behaviour, and availability
Authors: Kruuk Hans
Published: November 2023

Most of the otter prey species in Shetland were least active by day, and at low tide, when they were hiding and were therefore easiest to catch for a foraging otter. Butterfish and shore crabs were more common than eelpout and rocklings, which were the species taken most by otters. In Shetland otters selected the larger individuals from prey populations, but elsewhere they took non-selectively from the bottom-living prey species. The main prey species in Shetland lived in different, well-separated habitats along the coast, and this was likely to affect the size of ranges which otters needed to exploit such prey. There was a glut of potential prey in midsummer, and fish were scarce and relatively small during late winter and spring. Sites from which we repeatedly removed all fish were repopulated within a day, providing otters with places for sustained harvesting. Predators may have major effects on communities of prey species, and otters took a high proportion from populations of salmonidfish in Scotland, but the effect of otters on fish populations along the Shetland shore was probably small.
Otters fishing: hunting behaviour and strategies
Authors: Kruuk Hans
Published: November 2023

The usual hunting behaviour of otters in the sea consisted of swimming along the surface in daytime, diving in shallow water, and capturing small fish from their hiding places. Swimming speeds are described, as well as diving, handling, and eating of prey. Occasionally otters captured other animals such as aquatic birds, and they caught rabbits in their burrows. Otters were active during the day in Shetland and at night in many other places, because of the activity pattern of their prey species, the majority of which were caught when inactive. In the sea there was also a tidal effect, with otters foraging least during high tide. Success rates appear to be partly predetermined (otters fishing when there is a maximum likelihood of success). Differences in success rates between areas appeared to be related to prey size, and there was little variation in success rates between different depths of water and between seasons, with overall diving success around 27per cent in the sea.
Populations,survival,and mortality
Authors: Kruuk Hans
Published: November 2023

Different ways of assessing numbers of otters are discussed, including direct observation, spraint surveys (which should be treated with caution), stratified density sampling of otter holts, and the use of radionuclide-labelled spraints. Densities were found of one adult per 1−2 km ofcoast (Shetland) or 15 km of stream (north-east Scotland). Mortality patterns and age structure of populations are discussed; otters die relatively young, with a mean adult life expectancy of 3.1 years, and mortality rate gradually increases with age. Mercury is the only present-day pollutant on which we have information, which is likely to play a significant role in causing mortality amongst Scottish and Shetland otters. Prey availablity appears to affect both mortality and recruitment very strongly, but in different ways: mortality in spring, recruitment in summer. Females may deliberately abandonyoung cubs.
Systematics and phylogeny
Authors: Zann Richard A
Published: November 2023

Zebra Finches belong to the estrildine group of finches of which there are approximately 124 species found mainly in the tropical and subtropical parts of Africa, India, South-East Asia, Australia and Melanesia. Estrildines are the only granivorous group of passerines endemic to Australia and authorities recognise 18 species, of which the Zebra Finch is the most widespread and numerous.
Life history and adaptations
Authors: Zann Richard A
Published: November 2023

The primary aim of the final chapter is to integrate the various anatomical, physiological and behavioural attributes of Zebra Finches in order to understand the principal thrusts of their life histories and adaptations.
Continuous time and age-structure
Authors: Hassell Michael P
Published: November 2023

Most of the host-parasitoid systems explored so far in this book have involved coupled interactions with discrete and synchronised generations. Such discretegeneration life cycles are most frequently found in univoltine species in temperate regions where seasonality often synchronises populations and provides a natural interval between the appearance of successive generations. Seasonality also often synchronises the appearance of the first generation of multivoltine species within a year, although successive generations throughout the season tend to show progressive overlap of their life-cycle stages. Focusing on discrete-generation life cycles does not mean that age-structure is necessarily neglected in these models. For example, the combination of parasitoids and additional host density dependence requires specific assumptions about the order with which these occur in the host’s life cycle, which is then reflected in the model structure (Chapter 3, p. 46). Another example, in this case with an explicit treatment of age-structure, was discussed in Chapter 4, p. 90, involving the stabilising effects of phenological asynchrony between hosts and parasitoids within a single generation period.
Metapopulations of hosts and parasitoids
Authors: Hassell Michael P
Published: November 2023

The spatial interactions between hosts and parasitoids discussed in Chapter 4 assume complete mixing of the dispersing individuals of both populations at least once during each generation period. It is as if the individuals enter a ‘global pool’ and then redistribute themselves amongst the patches according to particular rules. This implies that individuals are able to disperse widely across their entire habitat which, in turn, restricts the spatial scale that is appropriate for such systems.
Epilogue
Authors: Aiken S Robert , Leigh Colin H
Published: November 2023

Deforestation has a long and very complex history, most of which remains to be written. Systematic interest in the subject spans little more than a century, beginning with G. P. Marsh’s seminal Man and Nature (1864/1965). Palynological and archaeological evidence suggests that anthropogenic forest change can be traced to at least the early Holocene, while literary and other sources reveal many examples of deforestation since ancient times. Consider a few greatly simplified examples.
The role of the insulin-like growth factors in the nervous system
Authors: Sara Vicki R
Published: November 2023

The importance of serum and tissue extracts for the growth of cells in culture has been recognized since early this century when, for example, Carrel (1913) demonstrated that embryo extracts were necessary for the growth of cells in culture. The use of tissue culture in the field of neurobiology was initiated by Ross Harrison, who observed the outgrowth of embryonic tadpole neuronal fibres from cells grown on clotted lymph from adult frogs (Harrison 1907). His observations in vitro confirmed the neuronal theory proposed by Ramon y Cajal. Almost a half century later, Rita Levi-Montalcini and Victor Hamburger (1951) found that tumour tissue secreted a substance which stimulated neurite outgrowth from chick embryo. Rita Levi-Montalcini, together with Stanley Cohen, continued this work, which culminated in the pioneering discovery of nerve growth factor. Until recently, nerve growth factor was believed to be specific for the growth of sympathetic and sensory neurones, so that the analogous growth factor for the central nervous system remained elusive for many years.
Descriptive Text
Authors: Keay R W J
Published: November 2023

This is a family of the Gymnosperms which diffe from the Angiosperms ( the flowering plants) by not having the ovules enclosed in an ovary. The only gymnosperm indigenous in Nigeria is in this family, but several other genera in other gymnosperm families have been introduced. The Podocarpaceae is a family of 7 genera, largely in the southern hemisphere.
Phasic development in palms
Authors: Tomlinson P B
Published: November 2023

Palms have morphological attributes that facilitate developmental and demographic study. This chapter outlines these features of growth and construction, all of which are elaborated in later chapters. Growth processes themselves are complex; the essays on stem vasculature demonstrate this, but also shows that constructional principles can be recognized. The architecture of palms can be approached because simple rules that govern and sometimes constrain development can be recognized.
Embryo and seedling
Authors: Tomlinson P B
Published: November 2023

The seedling phase of development of the palm may be defined as beginning with the enlargement of the embryo some time after the fruit is mature (germination), until the exhaustion of the endosperm reserves of the seed itself, a point difficult to establish in the absence of any morphological change. An alternative would be to consider expansion of the first bladed seedling leaf (eophyll) as the end of seedling development, even though the endosperm might not be exhausted. Robertson (1983a) divided germination in Jubaeopsis into five stages, beginning with the emergence of the seedling from the seed and ending with the appearance of the first eophyll (first bladed leaf). The biochemical and structural changes which occur in the embryo and endosperm during germination are discussed later. ‘Embryology’ in the broad sense, i.e. including all phases of micro- and mega-gametophyte development as well as embryo development, is not considered in this book (but cf Robertson 1976a,b,c for a modern example).
Establishment phase
Authors: Tomlinson P B
Published: November 2023

The post-seedling phase of development is a highly significant one in the ontogeny of the palm because it is the foundation for the mature primary axis. For this reason, Tomlinson and Zimmermann (1966b) coined the term ‘establishment growth’ for the developmental changes involved in this phase. This term was used in preference to the older Erstarckungswachstum (lit. ‘strengthening growth’) of earlier German authors, e.g. Troll (1936) because the changes are not merely mechanical, but also physiological. Establishment growth occurs to some extent in all vascular plants, but only in monocotyledons is it pronounced, even in those which have secondary thickening.
Vascular anatomy of the stem
Authors: Tomlinson P B
Published: November 2023

Palms, because of their simple architecture, provide ideal objects for the study of economy and efficiency in organic construction. They have unbranched axes, each of which supports a terminal tuft of appendages (leaves), each leaf supported by a basal sheath. The palm stem represents the reinforced concrete of the structural engineer (Fig. 6.1), since its tissues can be thought of as a series of axially-orientated vascular bundles (steel rods) embedded in a parenchymatous ground tissue (concrete matrix). Unlike the engineer’s reinforced concrete, the vascular bundles of the palm stem are not necessarily uniformly distributed, but usually concentrated toward the stem periphery for maximum efficiency. The stem of many palms has an additional mechanical feature, unfamiliar to human engineers, in that it can increase its stiffness with age. This is a very efficient way of growing because it means that the palm is not excessively overbuilt. It is as if an engineer could design a struture that becomes increasingly stronger directly as increasing strength is required. If the life span of the structure is shortened accidentally by some factor other than mechanical failure, the initial investment in the aborted structure is minimized. In terms of the palm tree this ‘saved’ investment can be diverted to more appropriate ecological events, such as growing in height, or in reproduction.
Palm stem—mechanics, age determination, and hydraulics
Authors: Tomlinson P B
Published: November 2023

The palm stem, as in all erect woody axes, serves the three-fold functions of transport, mechanical support, and storage. The transport system moves water and mineral nutrients in the xylem from the roots to the leaves, and also moves assimilates (sugars) in the phloem from the leaves (‘sources’) to regions where they are either metabolized or stored (in ‘sinks’) such as root and shoot apices, developing inflorescences and fruits, and storage parenchyma. The mechanical function of erect axes is to support the leafy crown and appendages, and depends on efficient distribution of sclerenchyma. The storage function is evident as starch grains which accumulate in the ground parenchyma. The three functions are clearly separated in the differentiation between different kinds of stem tissues visible microscopically in a transverse section (Plate 7). Individual fibrovascular bundles represent the combined conducting-mechanical system; however, mechanical fibres are clearly segretated from the conducting cells of xylem and phloem. The parenchymatous ground tissue represents not only the storage tissue, but the matrix within which the fibrovascular system is embedded.
Conclusions
Authors: Lavocat René
Published: November 2023

As discussed by A. E. Wood in the introduction to this book, the question of the Africa-South America connection, evidenced by more or less apparent parallels in the flora and fauna of both continents, took on an entirely new dimension when plate tectonics demonstrated that today’s distinct continents were once united in a single mass, before being slowly separated by continental drift. For many years, the apparent similarities between the various faunal and floral elements were used as key arguments supporting, among other things, the existence of what was called the Gondwana continent. Now that we have indisputable geological proof of this phenomenon, it is probably less important to provide biological evidence for it. In fact, we should use our knowledge of the existence of the continent to understand further the biological relationships. Nevertheless, plate tectonics, particularly during transition stages, may not always reveal the precise timing or extent of continental movements. For example, the presence of a shallow epicontinental sea, which would not be revealed by plate tectonics, could have restricted migrations routes and hampered the migration of some animals. Clearly, such a sea would have been as difficult to cross as a deep ocean for small terrestrial vertebrates, but not for huge amphibian hadrosaurians.
Reconstructing phylogenetic trees and ancestral character states
Authors: Harvey Paul H , Pagel Mark D
Published: November 2023

We described in the previous chapter how living organisms come to contain information about their evolutionary history, and why this means that comparative analyses must utilize phylogenetic information. This chapter asks what phylogenetic information we need for comparative tests, and how we might obtain it. It will become evident that although defining the information that we need is fairly straightforward, getting it is another matter. In fact the overriding message of this chapter will be that in the absence of a good fossil record we can never be sure of evolutionary history. We often produce quite different pictures of the past by basing our reconstructions on evolutionary models that make different assumptions about the roles of processes such as natural selection and genetic drift. An important task for biologists is to define which models are based on the most biologically realistic assumptions.
Conclusion
Authors: Harvey Paul H , Pagel Mark D
Published: November 2023

The comparative method that we have described in this book depends on the interplay among phylogenetic inheritance, chance events, and adaptation to contemporary environments. To consider only one of these processes alone is to lose much that has intrigued evolutionary biologists since Darwin. Yet, although the comparative method has been in constant use over the past century or so, we can only echo Ridley’s (1983n) wonder that it remained virtually unchanged from Darwin’s time until a decade ago. Meanwhile, population genetics and experimental investigations had forged ahead. We hope that this book has shown why the quotation which opened our first chapter should soon become history: … ‘we must learn to treat comparative data with the same respect as we would treat experimental results’ (Maynard Smith and Holliday 1979, p. vii). We can already treat properly analysed comparative results with the same respect that we treat experimental results. And, as we have seen, each has a crucial role to play in the development of our field.
Plio-Pleistocene proboscideans from the southern bight of the North Sea and the Eastern Scheidt, The Netherlands
Authors: Essen Hans Van , Mol Dick
Published: November 2023

The Netherlands and the adjacent part of the North Sea are well known for their abundant remains of late Pleistocene mammals. On the other hand, fossils of Pliocene and early Pleistocene age are comparatively rare in this area. This chapter deals with dredged remains of proboscideans from the Plio-Pleistocene in the North Sea area.

Dredging operations in the floodplains of the rivers Rhine, Waal, IJssel and Meuse (Fig. 20.1) still yield many mammalian fossils. In most cases they are typical of the late Pleistocene (Weichselian, 100 000-12 000 years BP) and characterized by the woolly mammoth, Mammuthus primigenius and the woolly rhinoceros, Coelodonta antiquitatis. Other elements of this assem¬ blage are the bovids, Bison priscus and Bos primigenius; giant deer, Megaloceros giganteus; red deer, Cervus elaphus; reindeer, Rangifer tarandus, and carnivores such as hyaena, Crocuta spelaea, and lion, Panthera spelaea. Age determinations of such collections are necessarily based on the results of geological survey. As yet there are no 14C data on these fossils.
Loxodonta africana: range and distribution, past and present
Authors: Douglas-Hamilton Iain , Michelmore Frances
Published: November 2023

Despite its great size and ecological requirements, the African elephant has been a supremely successful survivor amongst Africa’s megafauna. The species, until recently, occupied almost every habitat south of the Sahara, with the exception of extreme desert and high alpine montane. This is in contrast to other parts of the world where certain proboscideans disappeared with the ascent of man.
Introduction
Authors: Haccou Patsy , Meelis Evert
Published: November 2023

Ethological research can have widely different goals, and accordingly, the collected data have different forms. In most instances, however, it involves detailed observation and recording of the behaviour of one or more individuals. In this book, we will consider the analysis of such detailed, continuous time records of behaviour. (For an example of an advanced statistical method for a different type of ethological data, see Hemelrijk and Ek, 1991.) The types of research questions may vary widely. One may, for instance, be interested in the way in which different individuals affect each others’ behaviour, or the effects of seasonality, or experimental treatment, e.g. drug administration. In spite of these differences in research questions, there is a universal requirement of accurate observational data and methods of analysis for such data. Over the past few decades, these requirements have led to improved facilities for acquiring and processing data, turning ethology into an increasingly quantitative science. Most behavioural experiments involving direct observations of sequences of events and the time at which they occur require (computer) event recorders. See Appendix II for examples of bard- and software, available under the names Camera, Observer and Analyst, see also Fig. 1.1. The application of these recorders saves time, increases the accuracy and reduces the number of errors considerably. A huge amount of data is readily produced and to analyse these data, statistical procedures are needed. Accordingly, the analysis of behavioural data has received much attention in the literature (e.g. Hazlett, 1977, Colgan, 1978, van Hooff, 1982, Colgan and Zayan, 1986, Martin and Bateson, 1986, Siegel and Castellan, 1988).
Analysis of Time Inhomogeneity
Authors: Haccou Patsy , Meelis Evert
Published: November 2023

Frequently, behaviour shows systematic and profound changes during the observation period. Such changes may consist of the appearance and/or disappearance of certain acts (e.g. meals or sleep) or characteristic sequences of acts (e.g. courtship behaviour). Changes may also concern the mean bout length. The day-night cycle of mosquitoes, for example, is accompanied by a change in the mean bout length of flights (Peterson 1980). However, behaviour may also change in a less obvious way, under externally constant circumstances. In that case, unless bouts have a deterministically determined length (like in pacing), changes in the time structure are hard to detect. It is very important to take time inhomogeneities into account since otherwise they may mask treatment effects and make the results of an analysis ambiguous. Furthermore, from an ethological point of view, the occurrence of inhomogeneities can be of importance in itself since it may indicate that there are motivational changes. From a mathematical point of view, to know whether or not the assumption of homogeneity is justified is of great practical importance as homogeneity reduces the complexity of the modelling and the data analysis considerably.
Tests for Exponentiality
Authors: Haccou Patsy , Meelis Evert
Published: November 2023

In this chapter we discuss methods for analysing the bout length distributions of the recorded behavioural categories. Since the CTMC is used as the basic model, these distributions are exponential under the null hypothesis (see Box 1.3). We therefore focus on detecting deviations from exponentiality. Our strategy is to investigate this for each act separately. In a CTMC or a semi-Markov chain the process of alternation between one state and the group of other states is a so-called alternating renewal process (e.g. Cox and Lewis, 1978). Thus, we give tests for the exponentiality of the residence times in one state of an alternating renewal process, irrespective of the residence times in the other state. We restrict our attention to so-called scale-invariant tests which do not depend on the recording time unit. Furthermore, we have chosen procedures that can easily be applied, since either the exact null distribution or the asymptotic distribution is known. The (approximate) critical values are listed in the tables in Appendix I.