bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing the Land Administration Process
Authors: Dale Peter , McLaughlin John
Published: November 2020

Technology rarely poses the major concerns in any effort to build and sustain an effective land administration infrastructure. Rather, the core challenges tend to be related to management issues, as will be discussed in this chapter. Management was described in our earlier book as the art and science of making decisions in support of certain perceived objectives. Like politics, it is the art of achieving the possible, the ability to get things done. Management skills are needed in order to implement policy decisions and to meet the objectives set for any organization. Good management seeks to do this in an optimum fashion—perfect solutions never arise. Management entails extrapolating trends from a limited range of facts—sufficient information is never available for decisions to be made with certainty as to their outcome. Better information will however bring about a better understanding of any system and hence create the possibility for its better operation. Information is needed to: 1. monitor what is going on so that areas where decisions need to be made can be identified; 2. help evaluate alternative strategies for dealing with the problems or opportunities that have been identified; 3. assist in selecting the right course of action; and 4. facilitate the implementation of whatever has been decided. Management operates at all levels from the personal to the institutional; for instance all individuals need to practise self-management in order to achieve their optimum personal goals. More particularly, management within an organization operates at three key levels—strategic planning, management control, and operational control. Strategic planning is the process whereby decisions are made on an organization’s objectives, including where the organization should position itself to cope with future trends and markets. Operational control involves the day-to-day processes of ensuring that routine tasks are carried out efficiently and effectively. Management control is the interface between these two, ensuring that adequate resources are secured, either in terms of people, money, or equipment, to achieve the organization’s mission and objectives.
Hybrid Waters: On Water,Nature, and Society
Authors: Swyngedouw Erik
Published: November 2020

In recent years, we have become increasingly aware of the importance of water as a critical good, and questions of water supply, access, and management, both in quantitative and qualitative terms, have become key issues (Gleick 1993; Postel 1992; Stauffer 1998). The proliferating commodification and privatization of water management systems; the combination of Global Environmental Change with increased demands from cities, agriculture, and industry for reasonably clean water; the inadequate access of almost a billion people on the planet to clean water (over half of whom live in large urban centres); the proliferating geopolitical struggle over the control of river basins; the popular resistance against the construction of new megadams; the political struggles around water privatization projects; and many other issues; have brought water politics to the foreground of national and international agendas (Shiklomanov 1990; 1997; Herrington 1996; Roy 2001). In the twentieth century, water scarcity was seen as a problem primarily affecting developing societies (Anton 1993). However, at the turn of the new century, water problems are becoming increasingly globalized. In Europe, the area bordering the Mediterranean, notably Spain, southern Italy, and Greece, is arguably the location in which the water crisis has become most acute, both in quantitative and qualitative terms (Batisse and Gernon 1989; Margat 1992; Swyngedouw 1996a). However, northern European countries, such as the UK, Belgium, and France, have also seen increasing problems with water supply, water management, and water control (Haughton 1996), while transitional societies in eastern Europe are faced with mounting water supply problems (Thomas and Howlett 1993). The Yorkshire drought in England, for example, or the Walloon/Flemish dispute over water rights are illuminating examples of the intensifying conflict that surrounds water issues (Bakker 1999). Cities in the global South and the global North alike are suffering from a deterioration in their water supply infrastructure and in their environmental and social conditions in general (Lorrain 1995; Brockerhoff and Brennan 1998). Up to 50% of urban residents in the developing world’s megacities have no easy access to reasonably clean and affordable water. The myriad socioenvironmental problems associated with deficient water supply conditions threaten urban sustainability, social cohesion, and, most disturbingly, the livelihoods of millions of people (Niemczynowicz 1991).
The Water Mandarins: The Contradictions of Urban Water Provision
Authors: Swyngedouw Erik
Published: November 2020

Billions of litres of water flow through the centre of Guayaquil each day, as the Rivers Daule and Babahoyo converge to form the River Guayas. Given this fact, it is perplexing to find that 35% of the inhabitants of the city do not have access to adequate and reliable water supplies and the whole city suffers from chronic absolute water shortages. In this and the next chapter, we shall explore the contradictions of urban water provision, which result in a sizeable part of the urban population, invariably the poorer end of the social spectrum, not having access to piped potable water. This situation, in turn, makes them easy victims of water speculators, the private water sellers that distribute water in non-serviced areas by means of tankers. In Guayaquil, approximately 400 tankers service a population of half a million people, or approximately 35% of the total urban population. These water-merchants buy water at a highly subsidized price (70 sucres/m3),while they sell it for up to 6,500 sucres/m3 (November 1993), a price of up to 300 times higher than that paid by low-volume consumers who receive water from the water company. We will also explore the strategies and structure of the water company, infrastructure and investment planning, price mechanisms and control structures in the light of these exclusionary and disempowering mechanisms of the existing water system. In short, we shall explore the contradictory dynamics of the ‘Water Mandarins’. The complex networks of those that hold control over the water tap, water infrastructure, and water distribution will be excavated in order to unearth the relations of power that infuse and eventually organize the intermittent flow of water in Guayaquil. Of course, analysing the changing dynamics of water supply in Guayaquil is like trying to hit a moving target. The field research for this book was completed in 1998. Since then, the public water company has awarded a concession to International Water Services, a Dutch-based subsidiary of Bechtel and Edison Spa, to operate, administer, and expand Guayaquil’s water and sewage services and infrastructure (see below).
Aging and the Aged
Authors: Macey Susan M. , Smith Geoffrey C.
Published: November 2020

Elders are the fastest growing segment of the American population. In 1900, average life expectancy was 47 years. In the 1990s this figure stood at 78 years (Satcher 1996). Thus, not only are there both a higher percentage and a greater number of elderly individuals, but they are living longer, thus presenting a unique opportunity and challenge for geographic research. An earlier summary of the geographic literature on aging details several well-developed themes (Golant et al. 1989). These include residential location and migration patterns, activity patterns, and environmental relationships. The same themes persist and have been joined by work in health and service provision. Newer issues appearing in the literature concern the implications of a spatial shift in the elderly population for personal and environmental outcomes, with both the natural and built environments being the objects of study. A notable characteristic of these geographic studies is their broad range of scales from the macro-level (migration) to the micro-level (daily living space). This chapter seeks to highlight representative and influential contributions made by geographers to our understanding of how these demographic and spatial shifts affect the North American scene and how they will continue to impact America in the twenty-first century. It takes a broad, but selective view of current aging research as geographers are just one group of social scientists studying the elderly population and much collaboration and overlap in interests occur. The objective is not to discuss the findings of individual research, but rather to explore the breadth of issues examined by geographers. Several themes will be explored, including demographics and the components of population change, migration patterns, residential location and housing, service and health delivery, and environmental issues of particular relevance to the elderly population. The aging of populations, and the growing number of older individuals, implies that the spatial mobility of the aged will be a growing force shaping societies. The migration patterns of older persons have attracted considerable attention among scholars in a host of disciplines and have continued to be a research focus in geography.
Geography of Religion and Belief Systems
Authors: Stoddard Robert H. , Prorok Carolyn V.
Published: November 2020

Spatial and environmental dimensions of religious behavior, artefacts, and attitudes are grist for the geographer’s intellectual mill because spiritually motivated convictions and actions play an important role in human affairs. It is not surprising, therefore, that the geography of religion and belief systems is an important, emerging field of study. We commence this chapter with a definition of the field, particularly as it entails distinctions that arise out of the highly personal nature that religious belief is accorded in the academy and society at large. A limited review and summary of trends in the field over the past decade follows, building on Kong’s (1990) and Sopher’s (1967, 1981) overviews. Although North American geographers are emphasized here, research in the geography of religion is thoroughly entwined in terms of scholars’ national origin, university training, and research perspectives, thus making distinctions in nationality difficult. Moreover, geographers who do not consider themselves to be geographers of religion and numerous nongeographers also make significant contributions to this field because their work clearly incorporates both religious and geographic components in their analysis and subject matter. We note that traditional empirical studies largely dominate the work published in the last decade. Nevertheless, humanistic research (Weightman 1996; Cooper 1997a; Prorok 1997; Osterrieth 1997), and the application of contemporary critical theory (Fielder 1995; Kong 1993a, b; Prorok 2000) in this field is gaining ground, particularly via recent dissertations and presentations at AAG meetings. Additional comments about future challenges and opportunities conclude the chapter. No universally accepted definition of religion exists, as illustrated by the hundreds already published and others continually being introduced (see e.g. a separate bibliographical category devoted annually to this definitional task in Social Compass: International Review of Sociology of Religion). Another indication that the term “religion” lacks a single, precise definition is the continual struggle, expressed repeatedly within the American judicial system, with questions about what are truly “religious” activities. Definitions vary in their emphasis on three contrasting perspectives: (1) a transcendental divinity; (2) an immanent spirituality that permeates all of life; and (3) an ethical philosophy.
Intelligent Machinery, A Heretical Theory (c.1951)
Authors: Turing Alan
Published: November 2020

Turing gave the presentation ‘Intelligent Machinery, A Heretical Theory’ on a radio discussion programme called The ’51 Society. Named after the year in which the programme first went to air, The ’51 Society was produced by the BBC Home Service at their Manchester studio and ran for several years. A presentation by the week’s guest would be followed by a panel discussion. Regulars on the panel included Max Newman, Professor of Mathematics at Manchester, the philosopher Michael Polanyi, then Professor of Social Studies at Manchester, and the mathematician Peter Hilton, a younger member of Newman’s department at Manchester who had worked with Turing and Newman at Bletchley Park. Turing’s target in ‘Intelligent Machinery, A Heretical Theory’ is the claim that ‘You cannot make a machine to think for you’ (p. 472). A common theme in his writing is that if a machine is to be intelligent, then it will need to ‘learn by experience’ (probably with some pre-selection, by an external educator, of the experiences to which the machine will be subjected). The present article continues the discussion of machine learning begun in Chapters 10 and 11. Turing remarks that the ‘human analogy alone’ suggests that a process of education ‘would in practice be an essential to the production of a reasonably intelligent machine within a reasonably short space of time’ (p. 473). He emphasizes the point, also made in Chapter 11, that one might ‘start from a comparatively simple machine, and, by subjecting it to a suitable range of ‘‘experience’’ transform it into one which was more elaborate, and was able to deal with a far greater range of contingencies’ (p. 473). Turing goes on to give some indication of how learning might be accomplished, introducing the idea of a machine’s building up what he calls ‘indexes of experiences’ (p. 474). (This idea is not mentioned elsewhere in his writings.) An example of an index of experiences is a list (ordered in some way) of situations in which the machine has found itself, coupled with the action that was taken, and the outcome, good or bad. The situations are described in terms of features.
Kings and Warriors Population and Landscape from Post-Roman to Norman Britain
Authors: Härke Heinrich
Published: November 2020

Moving our story forward into the first millennium AD, we are able, for the first time in Britain’s past, clearly to identify populations and estimate their sizes, and we begin to see not just some details of the cultural landscape and its uses, but also changing patterns of landownership and other determinant factors. The full elucidation of the processes and interactions requires the combined use of historical, archaeological, and environmental data, and while the emphasis here will be on archaeological approaches, historical and environmental evidence will be drawn on. The regional emphasis is on the south and east of the island, but parallel developments in the west and north will be referred to. The period covered in this contribution can be divided into three distinct phases, each with its own characteristics: the ‘Dark Ages’ of the fifth to early seventh centuries ad; the phase of urbanization and agricultural expansion of the later seventh to eleventh centuries; and the Norman period from ad 1066 onwards. While their differences make a chronological treatment by phases necessary, there are a number of common themes which have all been subject to intense ideological pressures, and which have undergone profound changes in thinking over the last several decades. The cultural landscape is not usually thought of as an ideological battlefield. But as early as 1890, Seebohm wrote in the introduction to his weighty tome on The EnglishVillage Community that the question of land management and ownership tackled in his book is fundamental to the ‘experiment . . . of freedom and democracy’ undertaken by the Englishspeaking nations (Seebohm 1890: pp. vii–viii). More recent work has highlighted this ideological link between the cultural landscape and identity (e.g. Schama 1995). The earlier part of the period covered in this chapter is crucial to the question of identity because many regional or national identities in Europe go back, or are believed to go back, to the middle centuries of the first millennium AD.
Empire, the Economy, and Immigration Britain 1850–2000
Authors: Peach Ceri
Published: November 2020

To survey the changes in British population between 1850 and 2000 requires some large-scale generalizations. At the beginning of my period, Britain had an empire that held a quarter of the world’s population, but by the end of the period Britain had become part of the European Union and contained one-sixth of the Union’s population. For the first hundred years of the period, Britain was exporting its population to the empire; for the last fifty years, the empire had struck back. The last 150 years have seen huge transformations of the British economy. There has been a shift from agriculture to industry and from industry to services. Coal production rose from 50 million tons in the middle of the nineteenth century to 300 million tons in 1913. By 1999 it had returned to below its 1851 level. Mining scarred the landscape of all the coalfields. Oil production rose from none in 1970 to about 128 million tonnes in 1997, but left hardly a mark on settlement. The steel industry rose and fell. In 1860 there was no crude steel produced (Mitchell 1975: 399). By 1960 25 million tons were produced and now it is down to about half that level. The United Kingdom has undergone the demographic transition. The population rose from 10 million in 1801 to 38 million in 1901 to 59 million now. Six million more people have left the United Kingdom than have entered it since 1851. A tide, from the beginning of the twentieth century, has swept the rural population into the biggest cities until the post-1950 backwash has scattered it out to suburbia, exurbia, and market towns. Urbanization has been followed by suburbanization; suburbanization by counter-urbanization. The Fordist system of mass production produced the Fordist city of mass-produced housing design, the Victorian, terraced inner city. The post-Fordist era hollowed out the inner cities and produced the green belts, the new towns, and the scatter of light industry. The new international division of labour squeezed the manufacturing employment of the country out to the third world.
How to believe a machine-checked proof
Authors: Pollack Robert
Published: November 2020

Suppose I say “Here is a machine-checked proof of Fermat's last theorem (FLT)”. How can you use my putative machine-checked proof as evidence for belief in FLT? I start from the position that you must have some personal experience of understanding to attain belief, and to have this experience you must engage your intuition and other mental processes which are impossible to formalise. By machine-checked proof I mean a formal derivation in some given formal system; I am talking about derivability, not about truth. Further, I want to talk about actually believing an actual formal proof, not about formal proofs in principle; to be interesting, any approach to this problem must be feasible. You might try to read my proof, just as you would a proof in a journal; however, with the current state of the art, this proof will surely be too long for you to have confidence that you have understood it. This paper presents a technological approach for reducing the problem of believing a formal proof to the same psychological and philosophical issues as believing a conventional proof in a mathematics journal. The approach is not entirely successful philosophically as there seems to be a fundamental difference between machine-checked mathematics, which depends on empirical knowledge about the physical world, and informal mathematics, which needs no such knowledge (see section 3.2.2). In the rest of this introduction I outline the approach and mention related work. In following sections I discuss what we expect from a proof, add details to the approach, pointing out problems that arise, and concentrate on what I believe is the primary technical problem: expressiveness and feasibility for checking of formal systems and representations of mathematical notions. The problem is how to believe FLT when given only a putative proof formalised in a given logic. Assume it is a logic that you believe is consistent, and appropriate for FLT. The “thing” I give you is some computer files. There may be questions about the physical and abstract representations of the files (how to read them physically and how to parse them as a proof), and correctness of the hardware and software to do these things; ignore them until section 3.1.
We’re on the road to nowhere: An exhibition of molecules to transport us
Authors: Emsley John
Published: November 2020

The rays of the Sun, and the motions of the Moon and Earth, provide energy in abundance. Light from the Sun is absorbed by plants on land and algae in the sea and is used to convert carbon dioxide into high energy carbohydrates, which in turn become oils. Together these provide most of the food energy for animals like ourselves. We can also harvest plants and trees and burn them to release this energy as heat. The sunlight which falls on barren terrain, or on the roofs of buildings, we can also gather by using solar panels to heat water or to make electricity. The sunlight which falls on the oceans leads to evaporation of water which is precipitated on land, and this too we can use to generate hydroelectricity. The Earth itself is a vast reservoir of heat below the crust, but this is not so easily tapped—although in parts of the world, such as New Zealand, hydrothermal heat is an important source of power. We can extract energy from the effects of the Earth’s daily rotation, partly through the weather systems this produces, by using windmills, and possibly through the rise and fall of sea levels, by using tidal barriers and wave power. These sources of clean energy should be able to provide all the fuel and electricity for a sustainable human population of several billion, provided we did most of our travelling on foot or by bicycle. How much these natural renewable sources could really provide is debatable, but we have the means to utilize them so they could supply enough food and energy for a world population of two or three billion, and at a level which allows for most of the high-tech living that we now take for granted. It might even be possible for most families to run a car, provided they were content to travel only a couple of thousand miles a year in it. The trouble is that there are already six billion of us, and forecasts are that this will reach ten billion by the middle of the next century. Most of these people will no doubt aspire to owning a car.
Elements from Hell: An exhibition of molecules that are mainly malevolent
Authors: Emsley John
Published: November 2020

The road to hell is paved with good intentions . . . so the old saying goes. In this Gallery I want to show you that this can be indeed true, but it is also true that the road to hell can be paved with evil intentions—sometimes all the way down to the pit of fire. Elements cannot really be described as coming from hell, nor can molecules, but they can produce effects that can only be described as satanic. Some elements that exist naturally can be very toxic, such as beryllium and lead, and the same is true of some natural molecules, such as atropine. We have seen in other Galleries that when chemists discover a natural molecule which has desirable properties, it is often possible to make a safer version that retains these properties, or even enhances them, while unwanted side-effects can be eliminated or at least toned down. The opposite is also possible. If the desired property of a molecule is its ability to kill, then it is possible to refine that aspect. What was merely dangerous can be made maliciously deadly. We begin our tour of the portraits of Gallery 8 with an inspection of one of these terrible molecules. Could Adolf Hitler have saved his Third Reich from defeat? Quite possibly. What he needed was a secret weapon to wipe out the Allied troops when they invaded the Normandy beaches of northern France on D-day, 6 June 1944. Then with a quick victory in the west he could have rushed his troops to meet the oncoming onslaught of Russian armies from the east, and maybe even have wiped out those invaders as well. Hitler was fond of secret weapons. Some, like the jet fighter, the V1 flying bomb and the V2 rocket bomb, were triumphs of engineering and did a lot of damage, but they were generally developed too late to save his empire. In fact Hitler had one secret weapon that was very cheap and easy to make, and that would have stopped advancing armies dead, but he never used it.
Introduction
Authors: Maynard Smith John , Szathmary Eors
Published: November 2020

Living organisms are highly complex, and are composed of parts that function to ensure the survival and reproduction of the whole. This book is about how and why this complexity has increased in the course of evolution. The increase has been neither universal nor inevitable. Bacteria, for example, are probably no more complex today than their ancestors 2000 million years ago. The most that we can say is that some lineages have become more complex in the course of time. Complexity is hard to define or to measure, but there is surely some sense in which elephants and oak trees are more complex than bacteria, and bacteria than the first replicating molecules. Our thesis is that the increase has depended on a small number of major transitions in the way in which genetic information is transmitted between generations. Some of these transitions were unique: for example, the origin of the eukaryotes from the prokaryotes, of meiotic sex, and of the genetic code itself. Other transitions, such as the origin of multicellularity, and of animal societies, have occurred several times independently. There is no reason to regard the unique transitions as the inevitable result of some general law: one can imagine that life might have got stuck at the prokaryote or at the protist stage of evolution. There are obvious difficulties in discussing unique events that happened a long time ago. How can we ever know that our suggested explanations are correct? After all, historians cannot agree about the causes of the Second World War. We accept that certainty is impossible, but there are several reasons why we think the enterprise is worth while. First, we have one great advantage over historians: we have agreed theories both of chemistry and of the mechanism of evolutionary change. We can therefore insist that our explanations be plausible both chemically, and in terms of natural selection. This places a severe constraint on possible theories. Indeed, the difficulty often lies, not in choosing between rival theories, but in finding any theory that is chemically and selectively plausible. Further, theories are often testable by looking at existing organisms.
The evolution of templates
Authors: Maynard Smith John , Szathmary Eors
Published: November 2020

In this chapter, we discuss the origin and early evolution of genetic replication. The argument is complex, so we start with a brief outline. Section 4.2 discusses the nature of replication. We draw a distinction between simple replicators, limited hereditary replicators and indefinite hereditary replicators. Continued evolution requires indefinite hereditary replicators: it seems that such replicators depend on some form of template reproduction. In section 4.3, we point out that there is an error threshold for the accuracy of replication: for a given total quantity of genetic information—for example, for a fixed number of bases—there is an upper limit on the error rate of replication. If the error rate rises above this limit, natural selection cannot maintain the information. This leads to what we have called Eigen's paradox. In the absence of specific enzymes, replication accuracy is low. Hence the total genome size must be small—almost certainly, less than 100 nucleotides. The genome is therefore too small to code for accurate replication machinery. There is a catch-22 situation: no enzymes without a large genome, and no large genome without enzymes. The next three sections discuss possible solutions to the paradox. Section 4.4 considers populations of replicating RNA molecules. We point out that the dynamics of replication are such as to lead to the stable coexistence of a diverse population, but we do not think that this constitutes a solution to the paradox. Section 4.5 discusses the hypercycle, a particular relationship between replicators that makes it possible for a greater total quantity of information to be maintained with a given accuracy of replication. We argue that the further evolution of hypercycles requires that they be enclosed within compartments, because otherwise they are sensitive to parasitic replicators. We also discuss, rather inconclusively, the possibility that, even in the absence of compartments, cooperation might evolve, by a processes analogous to kin selection, if the components of the hypercycle were confined to a surface. Finally, we discuss an alternative model, the stochastic corrector model. This also depends on the existence of compartments, but emphasizes the importance of stochastic effects arising if there are small numbers of each kind of molecule in a compartment. Essentially, small numbers serve to generate variation upon which selection can act.
Intragenomic conflict
Authors: Maynard Smith John , Szathmary Eors
Published: November 2020

The idea that there may be a conflict between different genetic elements—for example, between chromosomal and mitochondrial genes—is a natural one. A wide range of phenomena, from distorted sex ratios and male sterility in plants to the evolution of chromosome form, may best be understood in terms of such conflict. Before discussing examples, however, it is useful to define ‘genomic conflict’. Suppose that two genetic elements, A and B, influence some phenotypic trait, T. Suppose, further, that some value of the trait, TA, would evolve if only genetic elements A were effective, and an alternative value, TB, if only elements B were effective. If TA and TB are not the same, then there is a potentiality for genomic conflict between elements A and B. In this chapter, we are mainly concerned with cases in which the two genetic elements are present in the same cell: hence the term ‘intragenomic’ conflict. However, the definition can be applied when the elements are in different cells in the same organism, or in different organisms: ‘parent-offspring conflict’ (Trivers, 1974; Parker & MacNair, 1978) is a case in which there is a conflict between genes expressed in different organisms. The occurrence of intragenomic conflict depends on how the genes are transmitted. Imagine a single-celled asexual haploid organism, with a single chromosome containing no transposable elements, one copy of which is transmitted to each daughter cell. Suppose further that the cell contains no symbionts or accessory genetic elements. There would then be no possibility of intragenomic conflict. In practice, conflict arises because cells contain transposons, plasmids, organelles and symbionts, and are sexual. Most biologists find the phenomena of intragenomic conflict unfamiliar and unexpected. It might seem that a good way of making sense of the subject would be to classify the genes concerned according to whether they are in parasites, mutualists, organelles or chromosomes. The snag is that parasites can evolve into mutualists and vice versa, symbionts can become organelles, genes can transfer from organelles to chromosomes, and chromosomal genes may be well behaved, transposable or ‘driving’. For these reasons, we will discuss intragenomic conflict under four heads, according to the different ways in which genes can obtain an unfair advantage over their fellows.
Step-growth polymerization—basics and development of new materials
Authors: He Zhiqun , Whale Eric A .
Published: November 2020

Step-growth polymerization is often referred to as condensation polymerization, since often—but by no means always—small molecules such as water are released during the formation of the polymer chains. There are a number of differences in the way polymerization occurs in step-growth polymerization compared to chain-growth processes, and these have marked practical implications. The most obvious difference is that, as the name implies, the polymer chain grows in a step-wise fashion; the initial stage of the reaction involves the conversion of monomers to dimers and from these other lower molecular weight oligomers. It is only as the reaction nears completion that significant quantities of higher molecular weight material can be formed. Thus, in order to obtain effective molecular weights, the reaction must proceed almost to completion, indeed the molecular weight (in terms of the number average degree of polymerization xn) of the polymer can be linked to the extent of reaction (p) using eqn (1). Thus, in the simplest case of a difunctional (AB) monomer, when 50% of the available groups have reacted, the number average degree of polymerization is only 2. The consequence of eqn (1) is that high molecular weights in step-growth polymerizations are associated with highly efficient reactions that do not have side-reactions. Notwithstanding this, the types of molecular weights associated with chain-growth processes are not encountered in these processes (except in the case of monomers with more than two reactive groups where hyper-branched or even cross-linked polymers are possible). There is an additional complication, namely the role of cyclization. Kricheldorf has recently shown that under perfect conditions cyclization is the ultimate fate of any polymerization reaction. Thus, under extremely high conversions the prediction given by eqn (1) would overestimate the actual molecular weights produced. Molecules that undergo step-growth polymerization must have at least two reactive functional groups. If the functionality is greater than this, for example, trifunctional, then hyperbranched polymers or even cross-linked systems can be formed. Commonly, this involves the reaction of two different reactive difunctional monomers.
The formation of cyclic oligomers during step-growth polymerization
Authors: Haida Abderrazak Ben , Hodge Philip
Published: November 2020

Step-growth polymerization is controlled both by the efficiency of the synthetic routes chosen (as indicated in Chapter 4) and by statistical considerations. In particular, the formation of the desired polymer is almost always accompanied by a cyclic oligomer fraction. As the dilution increases, the chances of cyclization also increase, since polymerization is a second-order process involving the reaction between linear species, whereas cyclization, involving the (intramolecular) reaction between the two ends of a linear molecule, is inherently a first-order process. Cyclization is a particular feature of the early stages of a step-growth polymerization (up to extents of reaction of 98–99%), where a proportion of the end groups that react are on the same molecule. Hence, cyclics form. Since the chances of meeting of the end groups decrease rapidly as the distance between them increases, the cyclics are of relatively low molecular weight, that is, they are oligomers. Further reaction leads mainly to linear molecules, although at extremely high conversions the number of end groups is quite small and intramolecular reactions essentially terminate the process, such that it might be expected that all chains ultimately cyclize. Practically though, the levels of conversion necessary to obtain these very large rings are extremely high and difficult to obtain (either by virtue of side reactions, monomer imperfections, or simply the level of viscosity of high molecular weight polymer solutions). What is usually obtained, therefore, is a mixture of cyclics and linear molecules. However, since cyclic oligomers often differ considerably in, for example, solubility compared to their high molar mass linear homologues, separation is often relatively straightforward. The commercial importance of polymers produced by step-growth polymerization gives a particular significance to understanding the nature of such materials. The presence of cyclic oligomers can be detrimental to the polymer properties since their presence could cause problems during processing. For instance, cyclic oligomers of polyethylene terephthalate (PET) tend to migrate to the surface of spun fibres and, under certain conditions, they crystallize to produce a surface ‘bloom’ which interferes with subsequent dyeing. More recently, it is the reverse of cyclization, namely ring-opening polymerization, which has been a particular focus of attention.
Metrics Spaces for the Infinite Dimensional Diffeomorphisms
Authors: Grenander Ulf , Miller Michael I.
Published: November 2020

In this chapter the metric space structure of shape is developed by studying the action of the infinite dimensional diffeomorphisms on the coordinate systems of shape. Riemannian manifolds allow us to developmetric distances between the groupelements. We examine the natural analog of the finite dimensional matrix groups corresponding to the infinite dimensional diffeomorphisms which are generated as flows of ordinary differential equations.We explore the construction of the metric structure of these diffeomorphisms and develop many of the properties which hold for the finite dimensional matrix groups in this infinite dimensional setting.
Metrics on Photometric and Geometric Deformable Templates
Authors: Grenander Ulf , Miller Michael I.
Published: November 2020

In this chapter the metric structure developed for geometric transformations is extended to define a metric structure on the images which they act. Defined as an orbit under the finite and infinite dimensional groups we establish the necessary properties for measuring distance in the image orbit. We extend the results from not only geometric transformation of the images but also to photometric variation in the images.
Introduction
Authors: Kemp T.S.
Published: November 2020

There are about 4,600 species of animals today that are called mammals because, despite an astonishing diversity of form and habitat, they all share a long list of characters not found in any other organisms, such as the presence of mammary glands, the single bone in the lower jaw, and the neocortex of the forebrain. This makes them unambiguously distinct from their closest living relatives, and their unique characters together define a monophyletic taxon, the class Mammalia. Three subgroups are readily distinguished amongst the living mammals. The Monotremata are the egg-laying mammals of Australasia, consisting only of two species of echidna and a single platypus species; for all their primitive reproductive biology, monotremes are fully mammalian in their general structure and biology. The Marsupialia, or Metatheria are the pouched mammals, whose approximately 260 species dominate the mammalian fauna of Australia, and also occur as part of the indigenous fauna of the Americas. By far the largest group of living mammals are the Placentalia, or Eutheria with about 4,350 species divided into usually eighteen recent orders. It is virtually unanimously accepted that the closest living relatives, the sister group, of mammals consists of the reptiles and the birds. The only serious dissent from this view in recent years was that of Gardiner (1982) who advocated that the birds alone and mammals were sister groups, the two constituting a taxon Haemothermia, defined among other characters by the endothermic (‘warm-blooded’) temperature physiology. Gardiner certainly drew attention to some remarkable similarities between birds and mammals, notably the details of the endothermic processes, the enlarged size and surface folding of the cerebellum, and a number of more superficial morphological features. There was also some molecular sequence data supporting the Haemothermia concept, including the beta-globin gene and 18S rRNA. Gardiner’s view briefly became a cause célèbre in part for its sheer heterodoxy, but all concerned have since rejected it on the grounds that a careful, comprehensive analysis of the characters supports the traditional view (Kemp 1988b), particularly if the characters of the relevant fossils are taken into account (Gauthier, Kluge, and Rowe 1988).
Intensity measurements
Authors: Blow David
Published: November 2020

Once a suitable crystal has been obtained, a molecular structure investigation requires measurement of the intensities of as many Bragg reflections as possible. In this chapter, some of the options that must be decided by the experimenter will be considered, and some of the criteria used to assess the accuracy and completeness of the data will be presented. The experimenter has to make a number of strategic decisions in collecting the crystal intensity data. These include: • What X-ray source should be used? • What X-ray detector should be used? • Under what conditions should the crystal be maintained? • How long should each crystal be exposed? • What data collection technique will be used? • What resolution limit should be applied? The choice of source and detector will depend largely on what is available, but the major decision is whether to use facilities in the home laboratory or whether to use a synchrotron at a central facility. The energy released by absorption of X-rays in a crystal inevitably damages it. The process of radiation damage increases crystal disorder and reduces the intensity of scattering. The experimenter will ultimately have to abandon data collection from the damaged and disordered crystal. Under ideal experimental conditions, all the useful diffraction data can be obtained from a crystal long before radiation damage takes its toll, and radiation damage does not create a practical problem. At the other end of the scale, it may be necessary to combine the measurements from many crystals in order to obtain a complete set of diffracted intensities. There is no definite criterion to decide when a crystal is so badly damaged that it must be discarded. But if the measurements are going to be of highest quality, any observable change is bad news. The most serious effects occur in the part of the diffraction pattern at the highest observed resolution, where the observed intensities of the Bragg reflections will be altered most rapidly. The first observable effect of radiation damage is usually a reduction of high angle intensities due to increased disorder.
Can A Computer Have A Mind?
Authors: Penrose Roger , Gardner Martin
Published: November 2020

Over the past few decades, electronic computer technology has made enormous strides. Moreover, there can be little doubt that in the decades to follow, there will be further great advances in speed, capacity and logical design. The computers of today may be made to seem as sluggish and primitive as the mechanical calculators of yesteryear now appear to us. There is something almost frightening about the pace of development. Already computers are able to perform numerous tasks that had previously been the exclusive province of human thinking, with a speed and accuracy which far outstrip anything that a human being can achieve. We have long been accustomed to machinery which easily out-performs us in physical ways. That causes us no distress. On the contrary, we are only too pleased to have devices which regularly propel us at great speeds across the ground - a good five times as fast as the swiftest human athlete - or that can dig holes or demolish unwanted structures at rates which would put teams of dozens of men to shame. We are even more delighted to have machines that can enable us physically to do things we have never been able to do before: they can lift us into the sky and deposit us at the other side of an ocean in a matter of hours. These achievements do not worry our pride. But to be able to think - that has been a very human prerogative. It has, after all, been that ability to think which, when translated to physicaJ terms, has enabled us to transcend our physical iimitations and which has seemed to set us above our fellow creatures in achievement. If machines can one day excel us in that one important quality in which we have believed ourselves to be superior, shall we not then have surrendered that unique superiority to our creations? The question of whether a mechanical device could ever be said to think- perhaps even to experience feelings, or to have a mindis not really a new one. But it has been given a new impetus, even an urgency, by the advent of modern computer technology.
Introduction
Authors: Newnham Robert E.
Published: November 2020

The physical and chemical properties of crystals and textured materials often depend on direction. An understanding of anisotropy requires a mathematical description together with atomistic arguments to quantify the property coefficients in various directions. Tensors and matrices are the mathematics of choice and the atomistic arguments are partly based on symmetry and partly on the basic physics and chemistry of materials. These are subjects of this book: tensors, matrices, symmetry, and structure–property relationships. We begin with transformations and tensors and then apply the ideas to the various symmetry elements found in crystals and textured polycrystalline materials. This brings in the 32 crystal classes and the 7 Curie groups. After working out the tensor and matrix operations used to describe symmetry elements, we then apply Neumann’s Law and the Curie Principle of Symmetry Superposition to various classes of physical properties. The first group of properties is the standard topics of classical crystal physics: pyroelectricity, permittivity, piezoelectricity, elasticity, specific heat, and thermal expansion. These are the linear relationships between mechanical, electrical, and thermal variables as laid out in the Heckmann Diagram. These standard properties are all polar tensors ranging in rank from zero to four. Axial tensor properties appear when magnetic phenomena are introduced. Magnetic susceptibility, the relationship between magnetization and magnetic field, is a polar second rank tensor, but the linear relationships between magnetization and thermal, electrical, and mechanical variables are all axial tensors. As shown in Fig. 1.2, magnetization can be added to the Heckmann Diagram converting it into a tetrahedron of linear relationships. Pyromagnetism, magnetoelectricity, and piezomagnetism are the linear relationships between magnetization and temperature change, electric field, and mechanical stress. Examples of tensors of rank zero through four are given in Table 1.1. In this book we will also treat many of the nonlinear relationships such as magnetostriction, electrostriction, and higher order elastic constants. The third group of properties is transport properties that relate flow to a gradient. Three common types of transport properties relate to the movement of charge, heat, and matter. Electrical conductivity, thermal conductivity, and diffusion are all polar second rank tensor properties.