bluuebunny/crossref_metadata_2025 huggingface dataset:
Inherited or Congenital Optic Nerve Diseases
Authors: Quiros Peter A. , Sadun Alfredo A.
Published: November 2020

In this chapter, we discuss inherited/congenital optic nerve diseases and their related visual fields defects. It is important for the ophthalmologist to establish, on the basis of the visual fields defect whether the optic nerve is involved and, if so, whether this is at the level of the optic disc or further back. In addition, the visual fields defect can help establish whether the etiology is acquired or congenital. If the former is the case, then the visual fields defect may reveal an insult that is rapidly progressive and hence requires immediate and aggressive management. The diseases are divided into the categories of congenital optic disc anomalies and heredodegenerative optic atrophies. Congenital optic disc anomalies include aplasias, dysplasias (hyperplasia and hypoplasia), optic nerve colobomas and pits, anomalous disc elevations: pseudopapilledema with or without hyaline bodies (drusen), and tilted disc and crescents. Absence of the optic disc (aplasia) is extremely rare and only a few case reports have been published in the literature. Optic disc size varies and may be larger (hyperplasia) or smaller (hypoplasia) than normal. Hyperplasia is much less common than hypoplasia and is usually related to ametropias. Optic nerve hypoplasia (ONH) may be unilateral or bilateral and isolated or associated with different syndromes. It may be associated with good or poor visual prognosis. It is the most common congenital optic disc anomaly encountered in pediatric ophthalmic practice. When the nerve head is slightly or segmentally reduced, especially in the presence of normal visual acuity, the diagnosis is based on comparison of disc photographs or calculation of the ratio of the disc center-to-fovea distance to disc diameter. Usually this ratio is increased in hypoplasia and, if higher than 3.0, is almost diagnostic. Sometimes the hypoplastic disc is surrounded by a ring of sclera and a ring of hyperpigmentation, described as “double-ring sign”. Maternal diabetes and use of teratogenic agents such as phenytoin, alcohol, quinine, and cocaine may be associated with ONH.
Bioseparations Science and Engineering
Authors: Harrison Roger G. , Todd Paul W. , Rudge Scott R. , Petrides Demetri P.
Published: November 2020

Designed for undergraduates, graduate students, and industry practitioners, Bioseparations Science and Engineering fills a critical need in the field of bioseparations. Current, comprehensive, and concise, it covers bioseparations unit operations in unprecedented depth. In each of the chapters, the authors use a consistent method of explaining unit operations, starting with a qualitative description noting the significance and general application of the unit operation. They then illustrate the scientific application of the operation, develop the required mathematical theory, and finally, describe the applications of the theory in engineering practice, with an emphasis on design and scaleup. Unique to this text is a chapter dedicated to bioseparations process design and economics, in which a process simular, SuperPro Designer® is used to analyze and evaluate the production of three important biological products. New to this second edition are updated discussions of moment analysis, computer simulation, membrane chromatography, and evaporation, among others, as well as revised problem sets. Unique features include basic information about bioproducts and engineering analysis and a chapter with bioseparations laboratory exercises. Bioseparations Science and Engineering is ideal for students and professionals working in or studying bioseparations, and is the premier text in the field.
Teaching Music to Students with Special Needs
Authors: Hammel Alice M. , Hourigan Ryan M.
Published: November 2020

A practical guide & reference manual, Teaching Music to Students with Special Needs addresses special needs in the broadest possible sense to equip teachers with proven, research-based curricular strategies that are grounded in both best practice and current special education law. Chapters address the full range of topics and issues music educators face including parental involvement, student anxiety, field trips and performances, and assessment strategies. The book concludes with an up-to-date section of resources and technology information.
The Current Structure of Special Education in Our Schools
Authors: Hammel Alice M. , Hourigan Ryan M.
Published: November 2020

Legal wrangling, court decisions, and the timeline of a bill as it becomes law are not always met with public scrutiny or interest. However, there are many seminal moments that have shaped policies, legislation, and litigation in the areas of civil rights and the education of students with special needs. The keystone legislation examined in this chapter has continued to define us as a country and shape our public policy. Influenced by the civil rights movement, parents and advocates of students with special needs learned that true progress for their causes is steeped in the court houses and lawmaking bodies of our states, districts, and in Washington, DC. It is through legislation and litigation that change becomes reality. It was through this paradigm shift that the lives of students with special needs and their families improved. In addition, advocates learned that it is also possible to improve the quality of life for all students. It is through inclusion and an increasingly widened lens when viewing differences and diversity that all students (those with and without special needs) in our schools have the opportunity to learn and grow with those who are different. The path for all, then, is expanded and enriched for the experiences shared through an inclusive and diverse environment. While Linda Brown, and all other students who are African-American are now eligible to attend their neighborhood schools, students with special needs are often bused far from their neighborhoods to be educated with other students because the school system has decided to segregate them according to ability and disability. If Linda had autism today, she might have to ride a bus for an hour and a half (each way) to school every day when her local elementary school is no farther from her home than the Sumner School was in 1951. We clearly still have a long way to go in delineating the rights of all citizens to equal access under the law. The Brown v. Board of Education (1954) case was very important to the cause of those seeking to have students with special needs included in the public schools.
Microbiome
Authors: Keats Jonathon
Published: November 2020

Sequencing the 3.2 billion base pairs of the human genome took thirteen years and cost $3 billion. Yet even before the genome was released in 2003, scientists were beginning to question whether an index of our DNA, however exhaustive, would genetically encapsulate Homo sapiens . One of the most articulate skeptics was Joshua Lederberg, a Nobel Prize–winning biologist who pioneered the field of bacterial genetics in the 1950s, while Watson and Crick were discovering the double helix. Lederberg publicly expressed his reservations in the year 2000, amid rampant hype about the Human Genome Project including a Clinton White House press conference. “Just as scientists study entire ecological systems to see how the various parts interact,” he wrote in a syndicated editorial, “we must regard the human body as an extended genome. Its parts consist of the nuclear DNA genome (karyome), a chondriome (mitochondria), and what I call the microbiome: the menagerie of the body’s attendant microbes. We must study the microbes that we carry within us and on our surfaces as part of a shared embodiment.” Lederberg coined the term microbiome to echo the older word genome and to establish a sort of equivalence. If anything, his claim on behalf of single-cell organisms was understated. The average body is host to an estimated 100 trillion microbes, ten times the number of human cells. These microorganisms span some twenty-two phyla, with more than six hundred species living in the mouth and 150 species on each palm. Taken together that adds up to vast genetic diversity: human DNA contains approximately 23,000 genes. The microbiome may contain as many as 23 million. Were these microbes mere fellow travelers the numbers would make no difference. (Because of their minuscule size microorganisms comprise less than 2 percent of our body mass.) What makes them significant from a human perspective—and makes their genetic legacy inseparable from ours—is that they perform essential functions in concert with human cells, facilitating digestion, for instance, and also aiding the immune system.
Great Firewall
Authors: Keats Jonathon
Published: November 2020

The Chinese government declared 1996 the Year of the Internet. There wasn’t much to it: only one person in ten thousand was connected—at a modem speed of 14.4 kilobits per second—and 86 percent of the population had never encountered a computer. Even in universities email was still a novelty, haltingly introduced in 1994. Yet in one respect China was the most advanced nation on the planet. Using equipment supplied by Sun Microsystems and Cisco, the Chinese Public Security Bureau had corralled the entire country, all 3,705,000 square miles, within a fanghuo qiang, or firewall. The firewall promised to make the internet safe for autocracy. All online communication could be monitored, at least in principle, and access to any website could be denied. On February 1, 1996, Premier Li Peng signed State Council Order 195, officially placing the government “in charge of overall planning, national standardization, graded control, and the development of all areas related to the internet,” and expressly forbidding users “to endanger national security or betray state secrets.” Enforcement was arbitrary. Discipline was imposed by the dread of uncertainty. This was an inevitability, since the Public Security Bureau couldn’t possibly watch all online activity within China, let alone block every objectionable web page worldwide. Interviewed by Wired magazine, the computer engineer overseeing the fanghuo qiang bluntly explained his working policy: “You make a problem for us, and we’ll make a law for you.” In many countries such a firewall might have stifled development, but most Chinese weren’t interested in making problems. They were attracted to the internet’s dazzling potential, as advertised on billboards that encouraged them to “join the internet club, meet today’s successful people, experience the spirit of the age, drink deep of the cup of leisure.” Those who could afford a connection, which cost approximately half the monthly salary of a recent college graduate, casually referred to the fanghuo qiang as the wangguan , calmly evoking the many guan (passes) of the Great Wall as natural features of China’s wan wei wang (ten-thousand-dimensional web).
Climate Change, Human Rights, and Moral Thresholds
Authors: Caney Simon
Published: November 2020

It is widely recognized that anthropogenic climate change will have harmful effects on many human beings and in particular on the most disadvantaged. In particular, it is projected to result in flooding, heat stress, food insecurity, drought, and increased exposure to waterborne and vector-borne diseases. Various different normative frameworks have been employed to think about climate change. Some, for example, apply cost-benefit analysis to climate change. The Stern Review provides a good example of this approach. It proceeds by comparing the costs (and any benefits) associated with anthropogenic climate change with the costs and any benefits of a program for combating climate change. On this basis, it argues that an aggressive policy of mitigation and adaptation is justified. Whereas the costs of combating climate change, according to Stern, are quite low, the costs of “business of usual” would be considerable. Other analysts adopt a second perspective and conceive of climate change in terms of its impact on security. For example, the High Representative and the European Commission to the European Council issued a statement on Climate Change and International Security, which argues that climate change is “a threat multiplier which exacerbates existing trends, tensions and instability.” It argues that climate change will contribute to the following kinds of insecurities: tensions over scarce resources; land loss and border disputes; conflicts over energy sources; conflict prompted by migration; and tensions between those whose emissions caused climate change and those who will suffer the consequences of climate change. In addition to the “economic” approach and “security-based” approach, some adopt a third different perspective, according to which the natural world has intrinsic value. This ecological approach condemns human-induced climate change because it is an instance of humanity’s domination and destruction of the natural world. For all of their merits, these three perspectives omit an important consideration: the impact of climate change on persons’ fundamental human rights. In this chapter, I argue that it is appropriate to analyze climate change in terms of its impact on human rights.
The Insula of the Menander at Pompeii: Volume 1: The Structures
Authors: Ling Roger , Arthur Paul , Clarke Georgia , Lazer Estelle , Ling Lesley A. , Rush Peter , Waters Andrew
Published: November 2020

This is the first of a three-volume analysis of the internationally renowned archaeological site called the Insula of the Menander, a major city block in ancient Pompeii. Volume one deals with the architecture within the block, especially with the House of Menander, the grand villa for which the site was named. Subsequent volumes will consider the decorations and household objects found during excavation.
I 10, 2-3
Authors: Ling Roger , Arthur Paul , Clarke Georgia , Lazer Estelle , Ling Lesley A. , Rush Peter , Waters Andrew
Published: November 2020

No part of I 10, 2-3 is protected by a modern roof, and the house is now in such a ruinous condition as to render interpretation difficult. The form of the house, like that of 1 10, 1, is very irregular. It has a street frontage of much the same width as its neighbour, but loses space at the rear to the latter’s kitchen yard; at the same time, its backmost rooms (10-12) project into the property behind (I 10,18). The result is a plan which is relatively broad and symmetrical at the front (north) but becomes progressively attenuated, with its axis misplaced westwards, at the rear. A central fauces (I 10, 3), with a painted lararium niche in its east wall (Pl 12), leads from the street to a broad but shallow ‘atrium’ (4) which provides access to the remaining parts of the house. The room to the left of the fauces operated in the final years as a shop (110, 2), with a wide opening to the street (Pl 3) and an L-shaped counter in the front part; it remained accessible from the interior of the house through a doorway into the eastern part of the ‘ atrium’, but also had an independent back room (8), which was separated from the ‘atrium’ by a timber-framed partition. The room to the right of the fauces (room 5) was roughly 2.80 m. square, with a fair-sized window (just under 1 m. wide and just over 1 m. tall) high up in the centre of its north wall (Fig. 39 (S26); cf. Pl 27) and a doorway from the ‘atrium’ (Pl 13) at its south-east corner. It retains a decorated pavement and (under a later decoration) wall-plaster of the period of the First Pompeian Style; there are also traces of a segmental vault evidently going back to the same phase. The ‘atrium’ is perhaps even less deserving of the name than its counterpart in 110,1. It is less than 3 m. deep and acts as little more than a hallway providing access between the fauces and the other parts of the house.
I 10, 7: Casa del Fabbro
Authors: Ling Roger , Arthur Paul , Clarke Georgia , Lazer Estelle , Ling Lesley A. , Rush Peter , Waters Andrew
Published: November 2020

In its present form the casa del fabbro is an attenuated and relatively cramped property. Not only is the width of its atrium complex so restricted as to allow space for only two narrow cubicula and a small.storeroom on one side, but the space to the east of the fauces has been detached to form part of a separate property (1 10, 6). At the rear, apart from a portico (10) with a kitchen (11) partitioned off at one end of it, there are no rooms beyond the line of the tablinum, merely a small garden enclosed by a blind wall. The full complement of living rooms on the ground floor consists, therefore, if we exclude the atrium (3), of a room occupied by a stair and a latrine (1) and a small cubiculum (2) to the west of the fauces, the two cubicula (4 and 5) and the storeroom (6) to the west of the atrium, the tablinum (7), and two larger rooms flanking it, one of which may have served as a cubiculum (8) and the other as a dining-room (9). The remaining living space was all upstairs. Here the only rooms which can definitely be identified are a series of four or five small chambers above rooms 1-2 and 4-6; but it is probable that there were further rooms above rooms 8 and 9, as well as the tablinum. Whether the house retained an upper floor over the space which had been ceded at its north-east corner, we have no means of telling (cf. p. 145). All this represents a contraction from earlier days, when the house had been interconnected with the Casa del Menandro, and the portico and garden area offered access to the rear (pp. 55, 79-81). That the house had come on harder times, or at least that it had passed into the hands of an owner or tenant with different cultural standards, is suggested by the decorations. The sole remaining fine-quality decorations are those of the late Third Style in rooms 8 and 9: redground wall-paintings with mythological pictures and black-ground ceiling-paintings in the former, and black wall-paintings with mythological landscapes and a painted cocciopesto pavement containing geometric patterns of tesserae in the latter.
Mortality and Morbidity in Modern Wars, II: Military Populations
Authors: Smallman-Raynor Matthew , Cliff Andrew
Published: November 2020

In the previous chapter, we looked at the main trends in morbidity and mortality in civil populations since 1850. In this chapter our focus shifts to the military. An invaluable recent source of information on this topic is Lancaster (1990: 314–40) who gives a disease-by-disease account of morbidity and mortality among soldiers from the seventeenth century. Until the twentieth century, soldiers were lucky to survive military medicine. Basic treatments included the cauterizing of wounds and the removal of limbs to prevent gangrene. The biggest early advances in military medicine came when doctors started to wash their hands. The role of Florence Nightingale in transforming the military hospitals during the Crimean War (1853–6), and her broader role in improving the welfare of the British Army, is legendary. Yet, notwithstanding the gigantic losses directly attributable to battle, up to World War I, most deaths in war among soldiers were caused by epidemic diseases like dysentery, enteric fever, cholera, typhus, plague, and simple infections like measles—the traditional killers encountered in civil populations. And, as with civil populations, the real advances in controlling these infections came with the development of antibiotics and vaccination after 1945. In this chapter, we begin by looking at mortality trends in a number of theatres of war between 1859 and 1914 using data from Curtin (1989). As a specific illustration of the role of one simple infectious disease, measles, as a cause of mortality in military camps during this period, we take the American Civil War (1861–5). By the end of World War I in 1918, the role of many infectious diseases as causes of military mortality and morbidity had changed from lethal to nuisance value. This shift is shown through an examination of the role of measles in World War I. After 1945, the use of antibiotics and the generalized availability of vaccination against most of the common infectious diseases ensured that the historic infectious diseases waned in their impact on military populations just as they did in civil populations. Again we use measles and the American army as examples to show these declining effects.
Social Power and the Urbanization of Water
Authors: Swyngedouw Erik
Published: November 2020

Taking as his case-study the city of Guayaquil in Ecuador, where 600,000 people lack easy access to potable water, Erik Swyngedouw aims to reconstruct, theoretically and empirically, the political, social, and economic conduits through which water flows, and to identify how power relations infuse the metabolic transformation of water as it becomes urban. These flows of water which are simultaneously physical and social carry in their currents the embodiment of myriad social struggles and conflicts. The excavation of these flows narrates stories about the city's structure and development. Yet these flows also carry the potential for an improved, more just, and more equitable right to the city and its water. The flows of power that are captured by urban water circulation also suggest that the question of urban sustainability is not just about achieving sound ecological and environmental conditions, but first and foremost about a social struggle for access and control; a struggle not just for the right to water, but for the right to the city itself.
Contested Waters: Rituals of Resistance and Water Activism
Authors: Swyngedouw Erik
Published: November 2020

The discussion in the previous chapters has shown how water is deeply embedded in the practice of everyday urban life, and how the uneven power over its control and the oppression caused by its absence result in it being highly contested terrain. A wide spectrum of social conflicts and struggles consequently unfold over the appropriation of and access to ‘metabolized’ urban water; struggles that are embedded in and embody social, political, and economic power relations. Put simply, the transformation of nature and the urbanization of nature’s water express the political economic and socio-ecological power relations that shape the urbanization process itself. The urban hydrosocial cycle is indeed infused with a myriad of social tensions and is contested terrain at each moment of its flow. We shall consider not only the strategies of the weak and the weapons they deploy, but also the tactics of the water vendors. Their control over water enables them to mobilize a range of tactics to maintain if not expand their hold over water and the appropriation of water rents. This chapter will explore these multifaceted dimensions of the social struggles around water and their political, economic and social significance. The most striking, if least powerful, actions are those waged by urban communities to gain or improve access to water. From the position of those facing oppressive mechanisms of water supply, four strategies have been identified (see, among others, Espinoza and Oliden 1988): passive acceptance, individual resistance, self-help, and social protest/mobilization. Notwithstanding the immense problems associated with problematic access to water, acceptance of the exclusive and/or exploitative status quo is very often the most common behaviour, resulting in the absence of collective action. Cotic and Dascal (1987) suggest that the nature of an eventual possible, but essentially private solution (i.e. domestic connection to a comprehensive networked system), results in passive acceptance as a particular form of response. While the demand for the provision of roads, schools, health services, or public transport is often subject to collective action and struggle,water (and waste disposal (Olaya 1991) ) has rarely resulted in popular and collective revolts.
The Human Dimensions of Global Change
Authors: Liverman Diana , Yarnal Brent
Published: November 2020

The human–environment condition has emerged as one of the central issues of the new millennium, especially as it has become apparent that human activity is transforming nature at a global scale in both systemic and cumulative ways. Originating with concerns about potential climate warming, the global environmental change agenda rapidly enlarged to include changes in structure and function of the earth’s natural systems, notably those systems critical for life, and the policy implications of these changes, especially focused on the coupled human–environment system. Recognition of the unprecedented pace, magnitude, and spatial scale of global change, and of the pivotal role of humankind in creating and responding to it, has led to the emergence of a worldwide, interdisciplinary effort to understand the human dimensions of global change. The term “global change” now encompasses a range of research issues including those relating to economic, political, and cultural globalization, but in this chapter we limit our focus to global environmental change and to the field that has become formally known as the human dimensions of global (or global environmental) change. We also focus mainly on the work of geographers rather than attempting to review the whole human dimensions research community. Intellectually, geography is well positioned to contribute to global environmental change research (Liverman 1999). The large-scale human transformation of the planet through activities such as agriculture, deforestation, water diversion, fossil fuel use, and urbanization, and the impacts of these on living conditions through changes in, for example, climate and biodiversity, has highlighted the importance of scholarship that analyzes the human–environmental relationship and can inform policy. Geography is one of the few disciplines that has historically claimed human–environment relationships as a definitional component of itself (Glacken 1967; Marsh 1864) and has fostered a belief in and reward system for engaging integrative approaches to problem solving (Golledge 2002; Turner 2002). Moreover, global environmental change is intimately spatial and draws upon geography-led remote sensing and geographic information science (Liverman et al. 1998). Geographers anticipated the emergence of current global change concerns (Thomas et al. 1956; Burton et al. 1978) and were seminal in the development of the multidisciplinary programs of study into the human dimensions of global change.
Can Automatic Calculating Machines Be Said To Think? (1952)
Authors: Turing Alan , Braithwaite Richard
Published: November 2020

This discussion between Turing, Newman, R. B. Braithwaite, and G. Jefferson was recorded by the BBC on 10 January 1952 and broadcast on BBC Radio on the 14th, and again on the 23rd, of that month. This is the earliest known recorded discussion of artificial intelligence. The anchor man of the discussion is Richard Braithwaite (1900–90). Braithwaite was at the time Sidgwick Lecturer in Moral Science at the University of Cambridge, where the following year he was appointed Knightsbridge Professor of Moral Philosophy. Like Turing, he was a Fellow of King’s College. Braithwaite’s main work lay in the philosophy of science and in decision and games theory (which he applied in moral philosophy). Geoffrey Jefferson (1886–1961) retired from the Chair of Neurosurgery at Manchester University in 1951. In his Lister Oration, delivered at the Royal College of Surgeons of England on 9 June 1949, he had declared: ‘When we hear it said that wireless valves think, we may despair of language.’ Turing gave a substantial discussion of Jefferson’s views in ‘Computing Machinery and Intelligence’ (pp. 451–2), rebutting the ‘argument from consciousness’ that he found in the Lister Oration. In the present chapter, Jefferson takes numerous pot shots at the notion of a machine thinking, which for the most part Turing and Newman are easily able to turn aside. Jefferson may have thought little of the idea of machine intelligence, but he held Turing in considerable regard, saying after Turing’s death that he ‘had real genius, it shone from him’. From the point of view of Turing scholarship, the most important parts of ‘Can Automatic Calculating Machines Be Said to Think’ are the passages containing Turing’s exposition of the imitation game or Turing test. The description of the test that Turing gave in ‘Computing Machinery and Intelligence’ is here modified in a number of significant ways. The lone interrogator of the original version is replaced by a ‘jury’ (p. 495). Each jury must judge ‘quite a number of times’ and ‘sometimes they really are dealing with a man and not a machine’. For a machine to pass the test, a ‘considerable proportion’ of the jury ‘must be taken in by the pretence’.
Twenty Five Years of Constructive Type Theory
Authors: Sambin Giovanni , Smith Jan M.
Published: November 2020

Per Martin-Löf's work on the development of constructive type theory has had a tremendous impact on the fields of logic and the foundations of mathematics. It also has broader philosophical significance and important applications in areas such as computing science and linguistics. This volume draws together contributions from researchers whose work builds on the theory developed by Martin-Löf over the last twenty-five years. As well as celebrating the anniversary of the birth of the subject it covers many of the diverse fields which are now influenced by type theory. It is an invaluable record of current activity and includes contributions from N. G. de Bruijn and William Tait, both important figures in the early development of the subject. Also published for the first time is one of Per Martin-Löf's earliest papers.
On storage operators
Authors: Nour Karim
Published: November 2020

λ-calculus as such is not a computational model. A reduction strategy is needed. In this paper, we consider λ-calculus with the left reduction. This strategy has many advantages: it always terminates when applied to a normalizable λ-term and it seems more economic since we compute λ-term only when we need it. But the major drawback of this strategy is that a function must compute its argument every time it uses it. This is the reason why this strategy is not really used. In 1990 Krivine (1990b) introduced the notion of storage operators in order to avoid this problem and to simulate call-by-value when necessary. The AF2 type system is a way of interpreting the proof rules for second-order intuitionistic logic plus equational reasoning as construction rules for terms. Krivine (1990b) has shown that, by using Gödel translation from classical to intuitionistic logic (denoted byg), we can find in system AF2 a very simple type for storage operators. Historically the type was discovered before the notion of storage operator itself. Krivine (1990a) proved that as far as totality of functions is concerned second-order classical logic is conservative over second-order intuitionistic logic. To prove this, Krivine introduced the following notions: A[x] is an input (resp. output) data type if one can prove intuitionistically A[x] → Ag[x] (resp. Ag[x] → ⇁⇁A[x]). Then if A[x] is an input data type and B[x] is an output data type, then if one can prove A[x] → B[x] classically one can prove it intuitionistically. The notion of storage operator was discovered by investigating the property of all λ-terms of type Ng[x] → ⇁⇁N[x] where N[x] is the type of integers. Parigot (1992) and Krivine (1994) have extended the AF2 system to classical logic. The method of Krivine is very simple: it consists of adding a new constant, denoted by C, with the declaration С: ∀X{⇁⇁ X → X} which axiomatizes classical logic over intuitionistic logic. For the constant C, he adds a new reduction rule which is a particular case of a rule given by Felleisen (1987) for control operator.
The forget-restore principle: a paradigmatic Example
Authors: Valentini Silvio
Published: November 2020

The aim of this paper is to give a simple but instructive example of the forget-restore principle, conceived by Giovanni Sambin as a discipline for a constructive development of mathematics and which first appeared in print in the introduction of Sambin and Valentini 1998. The best way to explain such a philosophical position is to quote from that paper: “To build up an abstract concept from a raw flow of data, one must disregard inessential details ... this is obtained by forgetting some information. To forget information is the same as to destroy something, in particular if there is no possibility of restoring that information ... our principle is that an abstraction is constructive ... when information ... is forgotten in such a way that it can be restored at will in any moment.” The example we want to show here refers to Martin-Löf’s intuitionistic type theory (just type theory from now on). We assume knowledge of the main peculiarities of type theory, as formulated in Martin-Löf 1984 or Nordström et al. 1990. Type theory is a logical calculus which adopts those notions and rules which keep total control of the amount of information contained in the different forms of judgement. However, type theory offers a way of “forgetting” information: that is, supposing A set, the form of judgement A true. The meaning of A true is that there exists an element a such that a ∈ A but it does not matter which particular element a is (see also the notion of proof irrelevance in de Bruijn 1980). Thus to pass from the judgement a ∈ A to the judgement A true is а clear example of the forgetting process. We will show that it is a constructive way to forget since, provided that there is a proof of the judgement A true, an element a such that a ∈ A can be reconstructed.
The origin of translation and the genetic code
Authors: Maynard Smith John , Szathmary Eors
Published: November 2020

The origin of the code is perhaps the most perplexing problem in evolutionary biology. The existing translational machinery is at the same time so complex, so universal, and so essential that it is hard to see how it could have come into existence, or how life could have existed without it. The discovery of ribozymes has made it easier to imagine an answer to the second of these questions, but the transformation of an ‘RNA world’ into one in which catalysis is performed by proteins, and nucleic acids specialize in the transmission of information, remains a formidable problem. We start, in section 6.1, by discussing changes known to have occurred in the code since its origin. Although these changes are minor, they do shed some light on how the code may have evolved in its very early days. In section 6.2, we ask what can be deduced from the present assignment of codons to amino acids, and from the phytogeny of tRNAs. Finally, in section 6.3, we come to grips with the hardest question: how did a specific association between particular amino acids and particular codons first come into existence? It is this association that is the essence of the code. Today, it plays a role in translation, but we think it first arose to serve quite a different function. If so, this is an example of a common feature of evolution: structures that today serve a complex function arose first to serve a simpler one. For many years the common genetic code was thought to be universal. Recently, some interesting exceptions have been found. These are of two types: either a stop codon is used to code for an amino acid, or a codon has been reassigned to a different amino acid. At first sight it is hard to see how this could happen. To alter the meaning of a codon in one particular gene might be a selective advantage, just as any mutation might be, but to alter its meaning wherever it occurs throughout the genome must surely be disastrous.
Pattern Theory
Authors: Grenander Ulf , Miller Michael I.
Published: November 2020

Pattern Theory provides a comprehensive and accessible overview of the modern challenges in signal, data, and pattern analysis in speech recognition, computational linguistics, image analysis and computer vision. Aimed at graduate students in biomedical engineering, mathematics, computer science, and electrical engineering with a good background in mathematics and probability, the text includes numerous exercises and an extensive bibliography. Additional resources including extended proofs, selected solutions and examples are available on a companion website. The book commences with a short overview of pattern theory and the basics of statistics and estimation theory. Chapters 3-6 discuss the role of representation of patterns via condition structure. Chapters 7 and 8 examine the second central component of pattern theory: groups of geometric transformation applied to the representation of geometric objects. Chapter 9 moves into probabilistic structures in the continuum, studying random processes and random fields indexed over subsets of Rn. Chapters 10 and 11 continue with transformations and patterns indexed over the continuum. Chapters 12-14 extend from the pure representations of shapes to the Bayes estimation of shapes and their parametric representation. Chapters 15 and 16 study the estimation of infinite dimensional shape in the newly emergent field of Computational Anatomy. Finally, Chapters 17 and 18 look at inference, exploring random sampling approaches for estimation of model order and parametric representing of shapes.
Introduction to Parallel Computing
Authors: Petersen Wesley , Arbenz Peter
Published: November 2020

In the last few years, courses on parallel computation have been developed and offered in many institutions in the UK, Europe and US as a recognition of the growing significance of this topic in mathematics and computer science. There is a clear need for texts that meet the needs of students and lecturers and this book, based on the author's lecture at ETH Zurich is an ideal practical student guide to scientific computing on parallel computers working up from a hardware instruction level, to shared memory machines and finally to distributed memory machines. Aimed at advanced undergraduate and graduate students in applied mathematics, computer science and engineering, subjects covered include linear algebra, fast Fourier transform, and Monte-Carlo simulations, including examples in C and in some cases Fortran. This book is also ideal for practitioners and programmers.
Basic Issues
Authors: Petersen Wesley , Arbenz Peter
Published: November 2020

Since first proposed by Gordon Moore (an Intel founder) in 1965, his law [107] that the number of transistors on microprocessors doubles roughly every one to two years has proven remarkably astute. Its corollary, that central processing unit (CPU) performance would also double every two years or so has also remained prescient. Figure 1.1 shows Intel microprocessor data on the number of transistors beginning with the 4004 in 1972. Figure 1.2 indicates that when one includes multi-processor machines and algorithmic development, computer performance is actually better than Moore’s 2-year performance doubling time estimate. Alas, however, in recent years there has developed a disagreeable mismatch between CPU and memory performance: CPUs now outperform memory systems by orders of magnitude according to some reckoning [71]. This is not completely accurate, of course: it is mostly a matter of cost. In the 1980s and 1990s, Cray Research Y-MP series machines had well balanced CPU to memory performance. Likewise, NEC (Nippon Electric Corp.), using CMOS (see glossary, Appendix F) and direct memory access, has well balanced CPU/Memory performance. ECL (see glossary, Appendix F) and CMOS static random access memory (SRAM) systems were and remain expensive and like their CPU counterparts have to be carefully kept cool. Worse, because they have to be cooled, close packing is difficult and such systems tend to have small storage per volume. Almost any personal computer (PC) these days has a much larger memory than supercomputer memory systems of the 1980s or early 1990s. In consequence, nearly all memory systems these days are hierarchical, frequently with multiple levels of cache. Figure 1.3 shows the diverging trends between CPUs and memory performance. Dynamic random access memory (DRAM) in some variety has become standard for bulk memory. There are many projects and ideas about how to close this performance gap, for example, the IRAM [78] and RDRAM projects [85]. We are confident that this disparity between CPU and memory access performance will eventually be tightened, but in the meantime, we must deal with the world as it is.
Symmetry
Authors: Newnham Robert E.
Published: November 2020

All single crystals possess translational symmetry, and most possess other symmetry elements as well. In this chapter we describe the 32 crystallographic point groups used for single crystals. The seven Curie groups used for textured polycrystalline materials are enumerated in the next chapter. We live in a three-dimensional world which means that there are basically four kinds of geometric symmetry operations relating one part of this world to another. The four primary types of symmetry are translation, rotation, reflection, and inversion. As pictured in Fig. 3.1, these symmetry operators operate on a point with coordinates Z1, Z2, Z3 and carry it to a new position. By definition, all crystals have a unit cell that is repeated many times in space, a point Z1, Z2, Z3 is repeated over and over again as one unit cell is translated to the next. A mirror plane perpendicular to one of the principal axes is a two-dimensional symmetry element that reverses the sign of one coordinate. Rotation axes are one-dimensional symmetry elements that change two coordinates, while an inversion center is a zero-dimensional point that changes all three coordinates. In developing an understanding of the macroscopic properties of crystals, we recognize that the scale of physical property measurements is much larger than the unit cell dimensions. It is for this reason that we are not concerned about translational symmetry and work with the 32 point group symmetries rather than the 230 space groups. This greatly simplifies the structure–property relationships in crystal physics. Aside from the identity operator 1, there are only four types of rotational symmetry consistent with the translation symmetry common to all crystals. Fig. 3.2 shows why. Parallelograms, equilateral triangles, squares, and hexagons will pack together to fill space but, pentagons symmetry axes are found in crystals. This is the starting point for generating the 32 crystal classes. When taken in combination with mirror planes and inversion centers, these four types of rotation axes are capable of forming 32 self-consistent three-dimensional symmetry patterns around a point. These are the so-called 32 crystal classes or crystallographic point groups.
Tensors and physical properties
Authors: Newnham Robert E.
Published: November 2020

In this chapter we introduce the tensor description of physical properties along with Neumann’s Principle relating symmetry to physical properties. As pointed out in the introduction, many different types of anisotropic properties are described in this book, but all have one thing in common: a physical property is a relationship between two measured quantities. Four examples are illustrated in Fig. 5.1. Elasticity is one of the standard equilibrium properties treated in crystal physics courses. The elastic compliance coefficients relate mechanical strain, the dependent variable, to mechanical stress, the independent variable. For small stresses and strains, the relationship is linear, but higher order elastic constants are needed to describe the departures from Hooke’s Law. Thermal conductivity is typical of the many transport properties in which a gradient leads to flow. Here the dependent variable is heat flow and the independent variable is a temperature gradient. Again the relationship is linear for small temperature gradients. Hysteretic materials such as ferromagnetic iron exhibit more complex physical properties involving domain wall motion. In this case magnetization is the dependent variable responsive to an applied magnetic field. The resulting magnetic susceptibility depends on the past history of the material. If the sample is initially unmagnetized, the magnetization will often involve only reversible domain wall motion for small magnetic fields. In this case the susceptibility is anhysteretic, but for large fields the wall motion is only partly reversible leading to hysteresis. The fourth class of properties leads to permanent changes involving irreversible processes. Under very high electric fields, dielectric materials undergo an electric breakdown process with catastrophic current flow. Under small fields Ohm’s Law governs the relationship between current density and electric field with a well-defined resistivity, but high fields lead to chemical, thermal, and mechanical changes that permanently alter the sample. Irreversible processes are sometimes anisotropic but they will not be discussed in this book. Measured quantities such as stress and strain can be represented by tensors, and so can physical properties like elastic compliance that relate these measurements. This is why tensors are so useful in describing anisotropy.
Electrical resistivity
Authors: Newnham Robert E.
Published: November 2020

The next six chapters describe the transport phenomena associated with the flow of charge, heat, and matter. In each case there is a vector flux that is governed by a vector field. Linear relationships between flux and field include electrical resistivity (Chapter 17), thermal conductivity (Chapter 18), diffusion (Chapter 19), and thermoelectricity (Chapter 21). All are represented by second rank tensors similar to electric permittivity (Chapter 9), but the underlying physics is somewhat different. Transport properties are nonequilibrium phenomena governed by statistical mechanics and the concept of microscopic reversibility, rather than the second law of thermodynamics that applies to equilibrium properties such as specific heat, permittivity, and elasticity. Higher order tensors appear when the transport experiments are carried out in the presence of magnetic fields or mechanical stresses. Galvanomagnetic, thermomagnetic (Chapter 20), and piezoresistance effects (Chapter 22) require third- and fourth-rank tensors. When an electric field is applied to a conductor, an electric current flows through the sample. The field Ei (in V/m) is related to the current density Jj (in A/m2) through Ohm’s Law, where ρij is the electrical resistivity (in Ω m). In tensor form, . . . Ei = ρijJj . . . Ei and Jj are polar vectors (first rank polar tensors) and ρij is a second rank polar tensor property which follows Neumann’s law in the usual way. Sometimes it is more convenient to use the reciprocal relation involving the electrical conductivity σij : . . . Ji = σijEj . . . .