bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Catastrophic Risks
Authors: Rees Martin J.
Published: November 2020

A global catastrophic risk is one with the potential to wreak death and destruction on a global scale. In human history, wars and plagues have done so on more than one occasion, and misguided ideologies and totalitarian regimes have darkened an entire era or a region. Advances in technology are adding dangers of a new kind. It could happen again. In Global Catastrophic Risks 25 leading experts look at the gravest risks facing humanity in the 21st century, including asteroid impacts, gamma-ray bursts, Earth-based natural catastrophes, nuclear war, terrorism, global warming, biological weapons, totalitarianism, advanced nanotechnology, general artificial intelligence, and social collapse. The book also addresses over-arching issues - policy responses and methods for predicting and managing catastrophes. This is invaluable reading for anyone interested in the big issues of our time; for students focusing on science, society, technology, and public policy; and for academics, policy-makers, and professionals working in these acutely important fields.
Cognitive biases potentially affecting judgement of global risks
Authors: Yudkowsky Eliezer
Published: November 2020

All else being equal, not many people would prefer to destroy the world. Even faceless corporations, meddling governments, reckless scientists, and other agents of doom, require a world in which to achieve their goals of profit, order, tenure, or other villainies. If our extinction proceeds slowly enough to allow a moment of horrified realization, the doers of the deed will likely be quite taken aback on realizing that they have actually destroyed the world. Therefore I suggest that if the Earth is destroyed, it will probably be by mistake. The systematic experimental study of reproducible errors of human reasoning, and what these errors reveal about underlying mental processes, is known as the heuristics and biases programme in cognitive psychology. This programme has made discoveries highly relevant to assessors of global catastrophic risks. Suppose you are worried about the risk of Substance P, an explosive of planet-wrecking potency which will detonate if exposed to a strong radio signal. Luckily there is a famous expert who discovered Substance P, spent the last thirty years working with it, and knows it better than anyone else in the world. You call up the expert and ask how strong the radio signal has to be. The expert replies that the critical threshold is probably around 4000 terawatts. ‘Probably?’ you query. ‘Can you give me a 98% confidence interval?’ ‘Sure’, replies the expert. ‘I’m 99%confident that the critical threshold is above 500 terawatts, and 99%confident that the threshold is below 80,000 terawatts.’ ‘What about 10 terawatts?’ you ask. ‘Impossible’, replies the expert. The above methodology for expert elicitation looks perfectly reasonable, the sort of thing any competent practitioner might do when faced with such a problem. Indeed, this methodology was used in the Reactor Safety Study (Rasmussen, 1975), now widely regarded as the first major attempt at probabilistic risk assessment. But the student of heuristics and biases will recognize at least two major mistakes in the method – not logical flaws, but conditions extremely susceptible to human error. I shall return to this example in the discussion of anchoring and adjustments biases (Section 5.7).
Some others
Authors: Weiner J. S. , Stringer Chris
Published: November 2020

Teilhard de Chardin was by no means the first helper in the search. Very probably the first person to hear of Dawson’s original fossil find, the piece handed to him by the labourer, was his friend of many years’ standing, Mr. Sam Woodhead, a schoolmaster at Uckfield, who combined his teaching duties with the post of Public Analyst. Woodhead had carried out the analysis of the natural gas reported by Dawson to the Geological Society in 1898. He shared the first excitement of the finds at Piltdown, and went back to Barkham Manor with Dawson a few days after the first find to look for more fragments, but, as Dawson has told us, their search was fruitless. Woodhead maintained his connection with the investigation, and it was he who carried out a chemical analysis of the skull at some time before 1912. He remained at Uckfield till 1916, the year of Dawson’s death. He was a man of considerable attainments, becoming a Doctor of Science and a Fellow of the Institute of Chemistry. He became Public Analyst for Brighton and Hove, and in 1916 went to live at Barcombe, the scene of Dawson’s third discovery of human remains. He was among those who attended Dawson’s funeral in Lewes in 1916. Woodhead often spoke of his early connections with the famous event to his wife and son and to others, such as Mr. Essex, another teacher, at Uckfield. Mr. A. J. Smith of Leamington remembers in a conversation in about 1925 that, in telling of the event, Woodhead chuckled over his ‘truancy’ from school that day when he helped Mr. Dawson in the pit, as he did on subsequent occasions. These visits in 1908 are well remembered by Mrs. Sam Woodhead. During the years from 1908 to 1911 Dawson showed one or more of the thick pieces of cranium to others among his friends and colleagues. Mr. Ernest Victor Clark4 was given the privilege of a private view of the fragments when he and his wife were dining with the Dawsons in Lewes, at some time in the autumn of 1911 or early in 1912.
Clinical operative procedures: a step-by-step guide
Authors: Banerjee Avijit , Watson Timothy F.
Published: November 2020

This chapter illustrates several minimally invasive operative dentistry procedures used for the successful placement of direct plastic restorations in the posterior and anterior dentition. The procedure list cannot be and is not exhaustive, but has been chosen to give the reader the broadest application of the techniques described. The techniques shown are not exclusive—there are many varied operative techniques for removing caries and placing suitable restorations (see Chapters 5 and 6), but the authors feel that the methods described are simple and achievable for most clinical abilities and in most clinical situations. The experienced skilled clinician is able to adapt the myriad of skills outlined in these examples to best fit the developing clinical situation presented to them. There are several classifications of cavities in the dental literature that attempt to correlate site, size of lesion, and disease activity. The oldest, simplest, and probably most universally accepted is Black’s classification (see Table 8.1). This classification was originally used to denote the most common sites for caries to develop, so helping to formulate an idea of the individual’s caries risk. Nowadays it is used to describe the site of the cavity or restoration, and is useful for descriptive purposes, communicating between dentists, or annotations in dental records. It must be understood that cavities should not be cut with predetermined geometric shapes according to this classification, but the classification should be used according to the final restoration placed, which will be governed by the biological extent of the caries, the type of material used, and other factors (e.g. amount/strength of tooth structure retained, occlusal factors, etc.). The remainder of this chapter will be dedicated to describing and illustrating the practical stages involved in placing certain types of restoration, outlining in detail the clinical procedures involved (see Tables 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 8.10, and 8.11). Discussion of the separate steps will be found throughout the preceding chapters, and these links are highlighted throughout. It is assumed that the clinical need for intervention has been appropriately ascertained and that any necessary local analgesia has been administered prior to commencement of the restorative procedures outlined.
Right iliac fossa pain
Authors: Farne Hugo , Norris-Cervetto Edward , Warbrick-Smith James
Published: November 2020

Note that certain diagnoses are going to be more likely in different patient groups. Children and elderly people are more likely to have a longer differential as symptoms are often less pronounced and non-specific. Intussusception is almost exclusively seen in children, and the vast majority of cases of mesenteric adenitis are also seen in children. By contrast, caecal pathology (tumours, volvulus, or a solitary mesenteric diverticulum) is usually associated with advancing age. An abdominal aortic aneurysm would be extraordinarily rare in a young adult but should be considered in anyone >50 years of age. You must of course consider gynaecological pathology, such as ectopic pregnancy, pelvic inflammatory disease/ salpingitis, torsion/haemorrhage/rupture of an ovarian tumour or cyst, mittelschmerz (mid-cycle pain corresponding to a ruptured ovarian follicle), threatened abortion, fibroid degeneration, or uterine dehiscence. In any woman of reproductive age you must perform a pregnancy test—this is not only to exclude particular diagnoses such as ectopic pregnancy, but is also essential to help weigh up the risk of radiation to the fetus against the diagnostic usefulness of the test. It is very useful to have an idea of the degree of abdominal tenderness before you even lay a hand on the patient. Remember that you will win no prizes (either in exams or with patients themselves) if you actually cause a patient pain. So, start by asking the patient to suck their tummy in as far as possible and then puff it out again (this is particularly useful in children). A patient with board-like abdominal rigidity secondary to generalized peritonism will only make very minor movements. Now ask the patient to cough: patients with inflammation of the parietal peritoneum will be reluctant to cough deeply and may well place their hands over the area of tenderness. Whether you palpate the abdomen in quadrants or nine zones, be sure to start in the opposite area to that which the patient states is most painful. Start by palpating gently and keep looking at the patient’s face for a reaction. Patients are likely to demonstrate guarding (involuntary muscular rigidity in tender areas of the abdomen).
Before the Standing Stones: From Land Forms to Religious Attitudes and Monumentality
Authors: Salisbury Joyce E.
Published: November 2020

Any study of great prehistoric monuments from standing stones to pyramids involves exploring people’s spiritual beliefs. There had to be some strong sense of awe to motivate people to do the kind of extraordinary work to erect such monuments, and in the ancient world, religion served as the greatest motivator. There are many ways to study religion, and each academic discipline uses its own methods, which in turn shape its conclusions. Anthropologists compare different religions to see how different cultures express their beliefs; sociologists look at the functions religions serve to maintain a social cohesiveness. Psychologists of religion might look at the way religious feelings are manifest in individuals, and theologians try to explore deep truths about the nature of God. All these approaches reveal some truths about this complex phenomenon we call religion and the results often seem like those of the proverbial blind men describing parts of an elephant while missing the glory of the whole. I, too, will focus on one small part of the religious experience—the feeling that lies at the heart of those who have felt the spiritual, and while there have been many disciplines that have studied this religious experience, from psychology to philosophy to sociology, my approach is historical. I will try to explore the nature of people’s religious expression over time, as they change and as they stay the same. What is this religious feeling? As we might expect, there are many different interpretations and analyses of the nature of the religious experience. It may mean the capacity of feeling at one with something larger than oneself, which is the definition of ‘mysticism’. It maymean a belief in—a faith in—a supernatural being. For the purposes of this chapter, however, I will simply accept the experience as a capacity humans have to feel awe and reverence (Bellah 2011). This enduring sense of awe—what has been famously called the idea of the holy (Otto 1950)—lies somewhere at the heart of all subsequent religious impulses.
Icons of Antiquity: Remaking Megalithic Monuments in Ireland
Authors: Cooney Gabriel
Published: November 2020

Megalithic tombs dating to the Neolithic and Early Bronze Age (4000–2000 cal. BC) are a very distinctive aspect of the Irish landscape (Jones 2007; Scarre 2007). They are an important monumental aspect of this period and since the 1990s our understanding of this period has been complemented by an extensive record of settlement and related activity that has been revealed through development-led archaeology (e.g. Smyth 2011). A focus of antiquarian and archaeological interest since at least the nineteenth century, the basis of modern approaches to megalithic tombs includes the systematic Megalithic Survey of Ireland that was initiated by Ruaidhrí de Valera in the 1950s, under the auspices of the Ordnance Survey of Ireland (Ó Nualláin 1989; Cody 2002 are the latest volumes published) and the excavation of key sites, for example the passage tombs of Newgrange (O’Kelly 1982; O’Kelly et al. 1983) and Knowth (Eogan 1984; 1986; Eogan and Roche 1997; Eogan and Cleary forthcoming) in the Boyne Valley and Carrowmore in Co. Sligo (Burenhult 1980; 1984; 2001). Current work includes the excavation of individual sites, work on the sources used in tomb construction, reviews of particular megalithic tomb types, landscape and regional studies, archaeoastronomy and overviews for a wide readership. The known number of megalithic tombs on the island now approaches 1,600 and the majority of these can be categorized as falling into one of four tomb types whose names encapsulate key architectural features of each tradition, hence the terms portal tombs, court tombs, passage tombs and wedge tombs (Evans 1966, 7–15; Valera and Ó Nualláin 1972, xiii). Unsurprisingly, much of the focus of archaeological research has been on the role of these monuments for the people and societies who constructed them. Issues such as the date of construction of different tomb types (Cooney et al. 2011) and the relationship between them have been central to key debates about the Neolithic, informing such major topics as the date and character of the Mesolithic to Neolithic transition, the changing character of society over the course of the Neolithic, mortuary rites and traditions, and the links between Ireland, Britain, and north-west Europe at this time (Cooney 2000; Bradley 2007; Waddell 2010).
Roman Dolmens? The Megalithic Necropolises of Eastern Maghreb Revisited
Authors: Sanmartí Joan , Kallala Nabil
Published: November 2020

North Africa has a rich tradition of archaeological studies. Its origins and early development are linked to the modern colonization of the region by several European powers, but it has also had a remarkable continuity after decolonization, both in international cooperation missions and in solo work developed by the research institutions of the Maghreb states, most particularly in Tunisia. However, this research has been extremely biased as regards the periods and cultures studied, since, due to easy to imagine political reasons related to the European colonization, the Roman period and the remains of early Christianity constituted a primary aim of the research. For this reason, pre-Roman levels that lie below the vast majority of Roman sites have been hardly explored. Although this state of affairs persisted after decolonization, it has been slowly changing in recent years. The situation is somewhat different with regard to funerary archaeology, as North Africa, especially its eastern portion, is characterized by the existence of a surprising number and diversity of pre-Roman sepulchral monuments (there are tens of thousands of recorded monuments) (Camps 1961). Owing to their high visibility, these monuments constitute the best-known aspect of North Africa’s pre-Roman archaeology. Yet, current knowledge on them is still limited due to the small number of excavations that have been carried out following modern methodology. In addition to the large monumental tombs linked to Numidian monarchies (strongly inﬂuenced by Punic and Hellenistic models), we can mention, among others, the following types: rock-cut chamber tombs (known as haouanet); large mounds that hide funerary chambers that are completely invisible from the outside (at times, they are bordered by more or less substantial walls; they are then called bazinas); tower-shaped monuments (called chouchet in Algeria); other structures are essentially similar to European dolmens, and still others consist of generally small built chambers surrounded by circular walls and covered by megalithic slabs; very frequently these are also called ‘dolmens’, although they do not have any side access and they frequently do not seem to be collective graves.
Burning Planet
Authors: Scott Andrew C.
Published: November 2020

Raging wildfires have devastated vast areas of California and Australia in recent years, and predictions are that we will see more of the same in coming years as a result of climate change. But this is nothing new. Since the dawn of life on land, large-scale fires have played their part in shaping life on Earth. Andrew C. Scott tells the whole story of fire's impact on our planet's atmosphere, climate, vegetation, ecology, and the evolution of plant and animal life. It has caused mass extinctions, and it has propelled the spread of flowering plants. The exciting evidence we can now draw on has been preserved in fossilized charcoal, found in rocks hundreds of millions of years old, from all over the world. These reveal incredibly fine details of prehistoric plants, and tell us about climates from deep in earth's history. They also give us insight into how early hominids and humans tamed fire and used it. Looking at the impact of wildfires in our own time, Scott also looks forward to how we might better manage them in future, as climate change has an increasing effect on our world.
Who Lived and Worked in the Base?
Authors: James Simon
Published: November 2020

Information about the specific imperial military contingents resident in the city, and their composition, comes from formal inscriptions, dipinti, graffiti, and Dura’s famous papyri, including part of the archive of cohors XX Palmyrenorum. The case of Dura’s garrison illustrates the validity of Millar’s call for a general review of evidence and interpretations regarding Dura-Europos (Millar 1998, 474). While the inscriptions still remain to be definitively published, it is sixty years since Final Report 5.1 on Dura’s papyri appeared, during which there have been a further two generations of general scholarship on the Roman military. These have seen fundamental changes in understandings of the subject, while several publications on specific aspects of Dura’s Roman military presence are also yet to be integrated into any wider reconsideration of garrison and city. Notably, Kennedy’s work has substantially revised understandings of the chronology and development of one of the major garrison elements, cohors XX Palmyrenorum (Kennedy 1983; 1994), while Edwell has effectively demolished the long-established wisdom that the garrison was, in its later decades, under an officer called the dux ripae, supposedly a regional commander foreshadowing the territorial duces of the Dominate (Edwell 2008, 129–35). Dura’s military presence also needs to be reconsidered against the background of broader recent developments in Roman military studies. Key is growing awareness of the importance of the ‘extended military community’, encompassing both soldiers and the many dependants who, it is now clear, routinely accompanied them. We will return to this aspect later. A fundamental restudy of the textual evidence for Dura’s Roman garrison is, then, overdue and needs to be undertaken by those with proper epigraphic expertise, but in its absence an interim review here is a necessary companion to the archaeological research on the base. Despite major subsequent discoveries such as the Vindolanda tablets (Bowman and Thomas 1983; 1994; 2003), the textual record for the Roman garrison at Dura remains unsurpassed by any other site, in its combination of scale, diversity of media, and detail. Some 60 per cent of Fink’s Roman Military Records on Papyrus comprised Durene documents (Fink 1971).
Life and work
Authors: Copeland Jack , Bowen Jonathan
Published: November 2020

A few months after Alan Turing’s tragically early death, in 1954, his colleague Geoffrey Jefferson (professor of neurosurgery at Manchester University) wrote what might serve as Turing’s epitaph: Alan in whom the lamp of genius burned so bright—too hot a flame perhaps it was for his endurance. He was so unversed in worldly ways, so childlike it sometimes seemed to me, so unconventional, so non-conform[ing] to the general pattern. His genius flared because he had never quite grown up, he was I suppose a sort of scientific Shelley. After his short but brilliant career Alan Mathison Turing’s life ended 15 days short of his fortysecond birthday.2 His ideas lived on, however, and at the turn of the millennium Time magazine listed him among the twentieth-century’s one hundred greatest minds, alongside the Wright brothers, Albert Einstein, DNA busters Crick and Watson, and Alexander Fleming, the discoverer of penicillin.3 Turing’s achievements during his short lifetime were legion. Best known as the mathematician who broke some of Nazi Germany’s most secret codes, Turing was also one of the ringleaders of the computer revolution. Today, all who click, tap, or touch to open are familiar with the impact of his ideas. We take for granted that we use the same slab of hardware to shop, manage our finances, type our memoirs, play our favourite music and videos, and send instant messages across the street or around the world. In an era when ‘computer’ was the term for a human clerk who did the sums in the back office of an insurance company or science lab, Turing envisaged a ‘universal computing machine’, able to do anything that a programmer could pin down in the form of a series of instructions. He could not have foreseen this at the time, but his universal computing machine changed the way we live: it eventually caught on like wildfire, with sales of personal computers now hovering around the million a day mark. Turing’s universal machine transported us into a world where many young people have never known life without the Internet.
The Enigma machine
Authors: Greenberg Joel
Published: November 2020

Shortly after the end of the First World War, the German Navy learned that its encrypted communications had been read throughout the hostilities by both Britain and Russia. The German military realized that its approach to cipher security required a fundamental overhaul, and from 1926 different branches of the military began to adopt the encryption machine known as Enigma. By the start of the Second World War a series of modifications to military Enigma had made the machine yet more secure, and Enigma was at the centre of a remarkably effective military communications system. It would take some of the best minds in Britain—and before that, in Poland—to crack German military Enigma. The exact origins of the encryption machine that played such an important role in the Second World War are not entirely clear. In the early 1920s patent applications for a wheel-based cipher machine were filed by a Dutch inventor, Hugo Koch, as well as by a German engineer, Arthur Scherbius. In 1923, a company called Chiffrienmaschinen AG exhibited a heavy and bulky encryption machine at the International Postal Congress in Bern, Switzerland. This machine had a standard typewriter keyboard for input, and its design followed Scherbius’s original patent closely. Scherbius had named his machine ‘Enigma’, and this ‘Model A’ was the first of a long line of models to emerge. Models B, C, and D soon followed, and by 1927 Model D was selling widely for commercial use. A number of governments purchased Enigma machines in order to study them, and Edward Travis—the deputy head of Britain’s signals intelligence unit, the Government Code and Cypher School—bought one on behalf of the British government in the mid-1920s. In 1925, the German Navy decided to put Enigma into use the following year, despite having rejected one of Scherbius’s previous encryption mechanisms in 1918. Meanwhile, the German Army began to redesign Enigma, with the intention of strengthening its security. By 1928, Model G was in use, and in June 1930 Model I (Eins) became the standard version, deployed first by the army, then the navy in October 1934, and the air force in August 1935.
ACE
Authors: Campbell-Kelly Martin
Published: November 2020

In October 1945 Alan Turing was recruited by the National Physical Laboratory to lead computer development. His design for a computer, the Automatic Computing Engine (ACE), was idiosyncratic but highly effective. The small-scale Pilot ACE, completed in 1950, was the fastest medium-sized computer of its era. By the time that the full-sized ACE was operational in 1958, however, technological advance had rendered it obsolescent. Although the wartime Bletchley Park operation saw the development of the electromechanical codebreaking bombe (specified by Turing) and the electronic Colossus (to which Turing was a bystander), these inventions had no direct impact on the invention of the electronic storedprogram computer, which originated in the United States. The stored-program computer was described in the classic ‘First draft of a report on the EDVAC’, written by John von Neumann on behalf of the computer group at the Moore School of Electrical Engineering, University of Pennsylvania, in June 1945. The report was the outcome of a series of discussions commencing in the summer of 1944 between von Neumann and the inventors of the ENIAC computer—John Presper Eckert, John W. Mauchly, and others. ENIAC was an electronic computer designed primarily for ballistics calculations: in practice, the machine was limited to the integration of ordinary differential equations and it had several other design shortcomings, including a vast number of electronic tubes (18,000) and a tiny memory of just twenty numbers. It was also very time-consuming to program. The EDVAC design grew out of an attempt to remedy these shortcomings. The most novel concept in the EDVAC, which gave it the description ‘stored program’, was the decision to store both instructions and numbers in the same memory. It is worth noting that during 1936 Turing became a research student of Alonzo Church at Princeton University. Turing came to know von Neumann, who was a founding professor of the Institute for Advanced Study (IAS) in Princeton and was fully aware of Turing’s 1936 paper ‘On computable numbers’. Indeed, von Neumann was sufficiently impressed with it that he invited Turing to become his research assistant at the IAS, but Turing decided to return to England and subsequently spent the war years at Bletchley Park.
Turing and randomness
Authors: Downey Rod
Published: November 2020

In an unpublished manuscript Turing anticipated by nearly thirty years the basic ideas behind the theory of algorithmic randomness, using a computationally constrained version of ‘measure theory’ to answer a question posed by Émile Borel in number theory: this question concerned constructing what are called ‘absolutely normal’ numbers. In this chapter we explain what these mysterious terms mean, and what Turing did. Mathematicians have always been fascinated with patterns in numbers. At an early stage in our education we learn about the special nature of decimal expansions of ‘rational numbers’, fractions that we can write in the form m/n, for some whole numbers m and n with n ≠ 0. The Greeks proved that some numbers, such as √2, 3√7 and √2 + √3 are not rational—indeed, it can be shown that ‘most’ numbers (in a precise mathematical sense) are irrational. It can be shown that a real number is rational if and only if it has a finite decimal expansion, or a decimal expansion that repeats from some point onwards; for example, 1/4 = 0.25 and 3/7 = 0.428571 428571 428571... . Note that we can also think of 1/4 as a repeating decimal, 0.25000000. . . ; we can also write it as 0.24999999 ... , but for simplicity we ignore such ambiguities. We can also count using bases different from 10. The binary system uses base 2, where each place in the representation corresponds to a power of 2; for example, just as 2301 in the decimal system refers to (2 × 103) + (3 × 102) + (0 × 101) + (1 × 100), so in base 2 the decimal number 13 = (1 × 23) + (1 × 22) + (0 × 21) + (1 × 20) is represented by 1101. In base 3 we use only the numbers 0, 1, 2 and express numbers using powers of 3, so the decimal number 25 = (2 × 32) + (2 × 31) + (1 × 30) is represented by 221. Note that when we use bases larger than 10 we have to invent extra symbols to represent the larger ‘digits’; for example, in base 12 we might use the digits 0, 1, 2, . . . , 9, T, E, with T and E representing ‘ten’ and ‘eleven’.
Is the whole universe a computer?
Authors: Copeland Jack , Sprevak Mark
Published: November 2020

The theory that the whole universe is a computer is a bold and striking one. It is a theory of everything: the entire universe is to be understood, fundamentally, in terms of the universal computing machine that Alan Turing introduced in 1936. We distinguish between two versions of this grand-scale theory and explain what the universe would have to be like for one or both versions to be true. Spoiler: the question is in fact wide open—at the present stage of science, nobody knows whether it’s true or false that the whole universe is a computer. But the issues are as fascinating as they are important, so it’s certainly worth while discussing them. We begin right at the beginning: what exactly is a computer? To start with the obvious, your laptop is a computer. But there are also computers very different from your laptop—tiny embedded computers inside watches, and giant networked supercomputers like China’s Tianhe-2, for example. So what feature do all computers have in common? What is it that makes them all computers? Colossus was a computer, even though (as explained in Chapter 14) it did not make use of stored programs and could do very few of the things that a modern laptop can do (not even long multiplication). Turing’s ACE (see Chapters 21 and 22) was a computer, even though its design was unlike that of a laptop; for example, the ACE had no central processing unit (CPU), and moreover it stored its data and programs in the form of ‘pings’ of supersonic sound travelling along tubes of liquid. Turing’s artificial neural nets were also computers (Chapter 29), and so are the modern brain-mimicking ‘connectionist’ networks that Turing anticipated. In connectionist networks—as in a human brain, but unlike a laptop—there is no separation between memory and processing, and the very same ‘hardware’ that does the processing (the neurons and their connections) also functions as the memory. Even Babbage’s Analytical Engine (Chapter 24) was a computer, despite being built from mechanical rather than electrical parts.
Learning disability
Authors: McKnight Rebecca , Price Jonathan , Geddes John
Published: November 2020

Disorders of intellectual development— or learning disability (LD)— denote a permanent impairment of intelligence associated with limitations of social func­tioning. A distinction is to be made between LD and dementia, the former originating early in life and the latter after 18 years of age. Although not reversible, much can be done to enable people with LDs to live as normally as possible. It is helpful for doctors to have basic knowledge of LD so they have an approach when the patient presents with physical or mental health problems and know when to refer to psychiatry. Several interchangeable terms are used to describe people with intellectual impairment originating early in life, including: … ● LD (common term used in Europe) ● Intellectual disability ● Disorder of intellectual impairment ● Mental retardation (this term is being phased out for ICD- 11 and has been removed from the DSM- 5). … The term LD implies more than intellectual im­pairment. It aims to separate those who cannot lead a near- normal life from people of the same IQ level who can. Patients with LD can be subdivided into categories which tend to be prognostically very useful (Table 19.1 and Box 19.1). A LD is not a clinical diagnosis in its own right, just a way of describing a particular clinical syndrome of impairments with disability and handicaps. The underlying diagnosis is the cause(s) of these impairments, which may or may not have been identified. The terms impairment, disability, and handicap are not interchangeable. The value of their use is in describing an individual’s specific needs, irrespective of their aetiological diagnosis. … ● Impairment is any loss or abnormality of psychological, physical, or anatomical structure or function. It is not dependent upon aetiology. ● Disability is any restriction in the ability to perform an activity within the range considered normal for a human at a corresponding level of development. ● A handicap is a disadvantage for a person, due to their impairment or disability, that prevents them from fulfilling a role that is normal for that individual…. The definition of LD as an IQ less than 70 (in combin­ation with an impairment of function) is based upon the assumption that IQ is normally distributed with a mean of 100 and standard deviation of 15.
Schizophrenia and related psychotic disorders
Authors: McKnight Rebecca , Price Jonathan , Geddes John
Published: November 2020

Schizophrenia and related disorders are a group of conditions characterized by psychotic symptoms which lead to impairments in thinking, feelings, be­haviour, and social interactions. There is a spectrum of severity. In schizophrenia, the patient suffers from both psychotic symptoms and functional impairment. In delusional disorders, the patient experiences de­lusions, but there is no evidence of hallucinations and their functional level may remain normal. Schizophrenia can be a particularly disabling illness because its course, although variable, is frequently chronic and relapsing. The care of patients with schizo­phrenia places a considerable burden on all carers, from the patient’s family through to the health and so­cial services. GPs may have only a few patients with chronic schizophrenia on their lists but the severity of their problems and the needs of their families will make these patients important. This chapter aims to provide sufficient infor­mation for the reader to be able to recognize the basic symptoms of schizophrenia and related dis­orders and to be aware of the main approaches to treatment. As the clinical presentation and outcome of the dis­order vary, schizophrenia can be a confusing illness to understand. It is best to start by considering simplified descriptions of two common presenta­tions: (1) the acute syndrome, and (2) the chronic syndrome. It is then easier to understand the core features as well as the diversity of schizophrenia. In the acute syndrome, the patient gains symptoms; they start to have unusual experiences or thoughts they did not previously, and act in bizarre or atypical ways. This is in contrast to the contrast to the chronic syndrome, in which there is a loss of function— the negative symptoms. The positive symptoms of schizophrenia may appear within a few days, or more insidiously over a period of weeks. A typical presentation is described in Case study box 22.1, and symptoms outlined in Table 22.1. It is not necessary for the patient to have all of these symptoms; they usually have a selection which may change over time.
Information
Authors: Hanson Robin
Published: November 2020

Interacting ems need not see exactly the same virtual environment. For example, each em might prefer to see a shared environment as decorated with their personal choices of colors or patterns. Ems might also prefer to overlay or augment their views of the virtual world with useful tags and statistics, or to see through virtual objects to see object components or to see what lies behind those objects. Virtual ems may have telescopic sight, allowing them to always vividly see anything anywhere they are allowed to view. However, overlays can impair perception, and so must be used carefully ( Sabelman and Lam 2015 ). To sensibly interact with others, ems usually want easy ways to quickly identify the aspects of their environments that they and their interaction partners see similarly. Some aspects of these worlds (such as where people are standing) are distinguished as shared by default, and interacting ems want standard ways to invite interaction partners to see some of their own less widely shared overlays and changes, and to accept such offers from others. At both work and play, many kinds of tasks require ems to manage physical systems. Such management often requires physical bodies (both immediate and extended) whose size, speed, shape, and materials sufficiently match those physical systems. It is also important for em minds to relate well to such bodies. But this seems feasible for a wide range of physical bodies. After all, people today interact with the world using a wide range of machines, such as vehicles and cranes, which they treat mentally as an extension of their bodies. For ems with task-matched physical bodies, the world they see and hear needn’t be an exact faithful representation of their physical world. For example, it might often be a sort of view like those in today’s head-up displays, overlaid with useful virtual annotations. But such overlays need to avoid overly obscuring important elements of that physical world. Because the feasibility, cost, and security of em interactions often depends on the physical and organizational locations of their brains and the brains of others, em virtual worlds may continually show such information about interaction partners. For example, ems often want to know when another em’s speed, period, phase, or distance makes direct fast interaction infeasible. So ems will need to share somewhat-realistic concepts of their locations in space and time.
Groups
Authors: Hanson Robin
Published: November 2020

Do ems physically concentrate in cities, or do they spread out more evenly across the land? Industrial economies today achieve large gains from clumping social and business activities closely together. The more easily that people can quickly travel to visit many different stores, employers, clubs, schools, etc., the more kinds of beneficial interactions become possible. The ability to interact via phones, email, and social media hasn’t reduced this effect; if anything the possibility of additional electronic interaction has usually increased the value of personal visits. Urban economists and other academics have long studied such “agglomeration” effects, and understand them in great detail. We should expect these gains from clumping to continue in an em world ( Morgan 2014 ). Ems want to be near one another, and near supporting tools and utilities, so that they could more easily and quickly interact with more such people and tools. This is especially important for fast ems, who can suffer noticeable communication delays with city scale separations. per person, cities today with twice the population tend to be 10% more economically productive per person. Compared with any given sized city, double-sized cities have per-person 21% more patents, 11% shorter roads, and 9% shorter electrical cables. But these cities also suffer 12% more crime, 17% more AIdS cases, and 34% more traffic congestion costs per person ( Bettencourt et al. 2007 , 2010 ; Schrank et al. 2011 ). Today, one factor increasing the productivity of larger cities is their selectively attracting better workers. But another important factor favoring big city productivity is their giving those better workers more ways to gain from their superior abilities. Optimal city size is in general a tradeoff between these gains and losses. During the farming era most people lived in small communities with populations of roughly 1000. Compared with any given sized village, only about 75% as many people lived in double-sized villages (Nitsch 2005). Thus most farmers lived in the smallest villages, because during the farmer era larger versions suffered higher costs of crime, disease, and transport.
Variations
Authors: Hanson Robin
Published: November 2020

This book has mostly discussed what the em era is like as if that era is stable and never changes. But we expect many changes and trends over the em era. For example, the size of the em economy grows exponentially, although this growth may fluctuate more than it does today because of concentration in a few key cities. Also, the cost of computing hardware falls exponentially, and with it the energy used per computing operation, and the natural em body size. parallel computing costs fall faster than serial computing costs, and also faster than the cost of non-computer tools. So there is a trend in workplaces away from using serial computer tools and noncomputer tools, and toward using em minds and parallel computer tools. parallel software becomes more efficient relative to the emulation process, inducing ems to use more software tools. The cost of communication rises relative to the cost of memory and computing, increasing communication delays, and reducing the rate of travel, meetings, and distances between meeting participants. As computing hardware is the main em labor cost, em subsistence wages and median wages fall with computing costs. Thus the speed-weighted size of the em population grows even faster than does the em economy. The typical sizes of firms, clans, and cities grow both with the size of the population, and with the size of the economy. While the first ems run near the speed of ordinary humans, there is an early transition to most ems running at a much faster common speed, estimated in Chapter 18 , Choosing Speed section to be within a factor of four of 1000 times human speed. But during the em era typical em speeds may slowly decline, as the growing em economy creates spatially larger em cities which signals take longer to cross. After an initial burst of exploration, the space of feasible tweaks of em minds slowly grows, but perhaps does not add much value. Added tweaks, random drift in capital per clan, and learning about which clans are best at which jobs should all contribute to a slow increase in the dominance of economy activity by the top few clans. The top clans slowly hold a larger fraction of the jobs, and own a larger fraction of capital.
Kingdom, Civitas, and County
Authors: Rippon Stephen
Published: November 2020

This book explores the development of territorial identity in the late prehistoric, Roman, and early medieval periods. Over the course of the Iron Age, a series of marked regional variations in material culture and landscape character emerged across eastern England that reflect the development of discrete zones of social and economic interaction. The boundaries between these zones appear to have run through sparsely settled areas of the landscape on high ground, and corresponded to a series of kingdoms that emerged during the Late Iron Age. In eastern England at least, these pre-Roman socio-economic territories appear to have survived throughout the Roman period despite a trend towards cultural homogenization brought about by Romanization. Although there is no direct evidence for the relationship between these socio-economic zones and the Roman administrative territories known as civitates, they probably corresponded very closely. The fifth century saw some Anglo-Saxon immigration but whereas in East Anglia these communities spread out across much of the landscape, in the Northern Thames Basin they appear to have been restricted to certain coastal and estuarine districts. The remaining areas continued to be occupied by a substantial native British population, including much of the East Saxon kingdom (very little of which appears to have been 'Saxon'). By the sixth century a series of regionally distinct identities - that can be regarded as separate ethnic groups - had developed which corresponded very closely to those that had emerged during the late prehistoric and Roman periods. These ancient regional identities survived through to the Viking incursions, whereafter they were swept away following the English re-conquest and replaced with the counties with which we are familiar today.
Introduction: Identity and alterity in Bronze Age Britain and Ireland
Authors: Brück Joanna
Published: November 2020

In 2004, excavation in advance of the construction of a bypass around Mitchelstown in County Cork uncovered a number of pits on the banks of the Gradoge River (Kiely and Sutton 2007). On the bottom of one of these pits, three pottery vessels and a ceramic spoon had been laid on two flat stones. The pots had been deposited in a row: at the centre of the row was a small vessel that clearly models a human face with eyes, a protruding nose and ears, and, at the base of the pot, two feet (cover images). Oak charcoal from the pit returned a date of 1916–1696 cal BC. This find calls into question one of the basic conceptual building blocks that underpins our own contemporary understanding of the world—the distinction between people and objects—for it hints that some artefacts may have been imbued with human qualities and agentive capacities. This book is about the relationship between Bronze Age people and their material worlds. It explores the impact of the post-Enlightenment ‘othering’ of the non-human on our understanding of Bronze Age society. As we shall see, there is in fact considerable evidence to suggest that the categorical distinctions drawn in our own cultural context, for example between subject and object, self and other, and culture and nature, were not recognized or articulated in the same way during this period. So too contemporary forms of instrumental reason—encapsulated in a particular understanding of what constitutes logical, practical action and in the distinction we make between the ritual and the secular—have had a profound effect on how we view the Bronze Age world. Our understanding of the Bronze Age has undoubtedly changed dramatically since Christian Jürgensen Thomsen first popularized the term in his famous formulation of the three-age system in 1836 (Morris 1992). The very notion of a ‘Bronze Age’ foregrounds concepts of technical efficiency and advancement that doubtless chimed with the preoccupations and cultural values of Thomsen’s audience in the industrializing world in the nineteenth century.