bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical approaches to language and aging
Authors: Burke Deborah M , Mackay Donald G , James Lori E
Published: November 2023

Research on cognition and aging has developed rapidly over the past several decades, moving beyond its early focus on psychometric intelligence tests to encompass new experimental paradigms and theoretical frameworks from cognitive psychology and the neurosciences. Although the accumulation of empirical findings has overshadowed the development of theories for explaining the patterns of cognitive change in old age, specification of theories of cognitive aging has undergone recent progress (e.g. Bowles 1994; Byrne 1998; Hasher and Zacks 1988; MacKay and Burke 1990; Myerson et al. 1990; Salthouse 1996). In this chapter, we describe a detailed theory of cognitive aging, the Transmission Deficit hypothesis, comparing it to other theories and demonstrating its account of evidence relating aging and language. We start with evidence indicating that effects of aging on language comprehension versus production are asymmetric, a phenomenon that sets a boundary condition for theories of cognitive aging. Although theories of cognitive aging have in general focused on cognitive decrements, these asymmetries indicate that they must also account for domains of performance that are preserved in old age, such as language comprehension. We compare two classes of cognitive aging theories for explaining asymmetric effects of aging on language: infonnation-universal and information-specific theories. Then we provide a detailed account within the Transmission Deficit model of how aging impacts three aspects of language production: tip-of-the-tongue experiences (TOTs), proper name recall, and retrieval of orthographic knowledge.
Integrating hippocampal and parietal functions: a spatial point of view
Authors: Burgess Neil , Jeffery Kathryn J , Keefe John O’
Published: November 2023

As an animal moves through its environment and interacts with it, many of the most important problems it faces involve the processing of spatial information. The animal needs to be able to perceive the locations and orientations of the objects around it relative to itself, to configure and move its receptors and effectors to sense and act upon these objects, and to move bodily through space so as to position itself in favourable locations or to avoid dangerous ones. The difficulty of solving these problems has been regularly demonstrated by the failure of artificial systems to perform such tasks efficiently. By contrast, animals routinely overcome these problems in their everyday life. This book examines some of the neural substrates and mechanisms supporting these remarkable abilities in humans and other mammals.
Multimodal integration for the representation of space in the posterior parietal cortex
Authors: Andersen Richard A
Published: November 2023

The posterior parietal cortex and the hippocampus are areas of the brain considered synonymous with spatial cognition. The classic studies of O’ Keefe & Nadel (1978) and their colleagues demonstrated cells in the hippocampus of rats selective for places in the environment. Given the amazing spatial properties of these cells, these authors proposed that the hippocampus con¬ tained a cognitive map of space. Likewise, lesions to the posterior parietal cortex of humans and non-human primates produce severe deficits in spatial perception. Thus the posterior parietal cortex has been considered essential for the perception of space. In primates the posterior parietal cortex projects to the presubiculum and parahippocampal gyrus and thus there are strong and rather direct connections between these areas. The loss of spatial memories after lesion of the posterior parietal cortex suggests that these memories are laid down there, with the aid of the hippocampus. In rats the posterior parietal cortex contains cells with properties similar to those of cells found in the hippocampus; this observation again suggests that these two structures play an intimate and associated role in the construction of spatial cognition. In this paper, data on how space is processed in the posterior parietal cortex in the macaque monkey are reviewed. An understanding of the spatial role of the parietal areas, when combined with new data that are emerging from studies of the monkey hippocampus (Uno et al. 1993; Rolls & Omara 1995; Satoshi et al. 1995), will help in understanding the roles these two structures play in spatial cognition. Likewise, the comparison of primates with rats will determine what spatial functions are similar or dissimilar between the two species.
Action-based mechanisms of attention
Authors: Tipper Steven P , Howard Louise A , Houghton George
Published: November 2023

Actions, which have effects in the external world, must be spatiotopically represented in the brain. The brain is capable of representing space in many different forms (e.g. retinotopic, environment-, head-, or shoulder-centred), but we maintain that actions are represented in action-centred space, meaning that, at the cellular level, the direction of movement is defined by the activity of cells. In reaching, for example, object location is defined as the direction and distance between the origin of the hand and the target. Most importantly, we argue that more than one task-relevant action can be evoked at any moment in time. Therefore, highly efficient selection processes that accurately link vision and action have had to evolve. Research is reviewed which supports the notion of action-based inhibitory mechanisms that select the target from competing distractor.
Transcription Factors that Control Schwann Cell Development and myelination
Authors: Topilko P , Meijer D
Published: November 2023

It is now well established that the continuous dialog between neuron and Schwann cell underlies the development, maintenance and regeneration of peripheral nerves (see Chapters 1 and 15). Most of the Schwann cells within the developing nerve, as well as the other glial cell types in the peripheral nervous system (PNS), such as the satellite cells, the teloglia and enteric glial cells, derive from the neural crest (Le Douarin et al., 1991; Anderson, 1997). Immature Schwann cells proliferate, migrate, invade, bundle and sort the axonal fibers of the embryonic nerve. This process continues until the Schwann cells ensheath individual larger caliber axons or multiple lower caliber axons. Schwann cells then cease to proliferate and commence to myelinate the larger axons, while the non-myelin-forming Schwann cells further ensheath multiple smaller axons resulting in the mature Schwann cell phenotypes observed in the nerves of adult animals (Webster, 1993). The differentiation of the two types of Schwann cells takes place during the first weeks of postnatal life in rodents. A number of distinct steps in the generation of mature Schwann cells can be distinguished. (i) Pluripotent neural crest stem cells must acquire a glial cell fate during entry into, or within the embryonic nerve. (ii) This glial cell population expands and invades the nerve bundle. (iii) Immature cells will adopt a promyelin-forming or a pro-nonmyelin-forming configuration with axons and cease to proliferate.
Introduction to kinetic analysis of enzyme systems
Authors: Johnson Kenneth A
Published: November 2023

The high resolution structural information available for many enzymes demands equally robust kinetic studies. It is the combination of structural and rigorous kinetic information that provides a powerful set of data necessary to establish mechanism. It is difficult to fully interpret kinetic data in the absence of structure, but it is dangerous to interpret structural information in the absence of kinetics.
Introduction
Authors: Schoonhoven Louis M , Loon Joop J A van , Dicke Marcel
Published: November 2023

Almost a century and a half ago W. Kirby and W. Spence described in their legendary book on entomology3 the flight of a large white butterfly in pursuit of a suitable plant to lay eggs on: ‘she is in search of some plant of the cabbage tribe. Led by an instinct far more unerring than the practised eye of the botanist, she recognizes the desired plant the moment she approaches it; and upon this she places her precious burden.
Herbivorous insects: something for everyone
Authors: Schoonhoven Louis M , Loon Joop J A van , Dicke Marcel
Published: November 2023

Insects have the most species of any class of organisms on earth and green plants make up the greatest part in all biomass on land. Nearly half of all existing insect species feed on living plants. Thus, more than 400 000 herbivorous (synonymous with phytophagous) insect species live on roughly 300 000 vascular plant species (Fig. 2.1).
Host-plant selection: when to accept a plant
Authors: Schoonhoven Louis M , Loon Joop J A van , Dicke Marcel
Published: November 2023

Variation is a basic characteristic of life. Obvious levels of variability are between species, families, orders, phyla, kingdoms, etc., but a surprisingly large variability also exists within species. This applies not least to host-plant choices in herbivores. The host-plant range of an insect species is not a fixed and unchangeable property. Meticulous studies have shown that some individuals or even whole populations of an insect species may reject plants, although they belong to the ‘normal’ host plant range of the species.
Assessing the Risk of Disclosure of Confidential Categorical Data
Authors: Dobra Adrian , Fienberg Stephen E , Trottini Mario
Published: November 2023

Maintaining the confidentiality of statistical data is essential if government agencies are to collect and publish high-quality census and survey data. Typically, agencies promise respondents that their data will be kept confidential and used for statistical purposes only. For example, Title 13, Section 9 of the United States Code prohibits the US Census Bureau from publishing results in which an individual’s or business’s data can be identified. How can an agency comply with such legal strictures while at the same time provide public access to as much data as possible? This paper addresses this issue in the context of categorical data in the form of a cross-classification of counts.
Markov chain Monte Carlo-based approaches for inference in computationally intensive inverse problems
Authors: Higdon Dave , Lee Herbie , Holloman Chris
Published: November 2023

A typical setup for many inverse problems is that one wishes to update beliefs about a spatially dependent set of inputs x given rather indirect observations y. Here, the inputs and observed outputs are related by the complex physical relationship y = Cfx) + ϵ Applications include medical and geological tomography, hydrology, and the modelling of physical and biological systems. We consider applications where the physical relationship C(x) can be well approximated by detailed simulation code y(x).
The Markov Modulated Poisson Process and Markov Poisson Cascade with Applications to Web Traffic Modeling
Authors: Scott Steven L , Smyth Padhraic
Published: November 2023

A Markov modulated Poisson Process (MMPP) is a Poisson process whose rate varies according to a Markov process. The nonhomogeneous MMPP developed in this article is a natural model for point processes whose events combine irregular bursts of activity with predictable (e.g. daily and hourly) patterns. We show how the MMPP may be viewed as a superposition of unobserved Poisson processes that are activated and deactivated by an unobserved Markov process. The MMPP is a continuous time model which may also be viewed as a discretely indexed nonstationary hidden Markov model by viewing intervals between events as a sequence of dependent random variables. The HMM representation allows one to probabilistically reconstruct the latent Markov and Poisson processes using a set of forward-backward recursions. The recursions allow MMPP parameters to be estimated either by an EM algorithm or by a rapidly mixing Markov chain Monte Carlo algorithm which uses the recursions for data augmentation. The Markov-Poisson cascade (MPC) is an MMPP whose underlying Markov process obeys certain restrictions which uniquely order the event rates for the observed process. The ordering avoids a possible label switching issue without slowing down the rapidly mixing algorithms we use to implement the model. We apply the MPC to a data set containing click rate data for individual computer users browsing through the World Wide Web. Because the complete data posterior distribution for the MPC is a product of exponential family distributions we are able to incorporate data from multiple users into a hierarchical model using existing methods from hierarchical Poisson regression.
General Theory of Small Fluctuations
Authors: Weinberg Steven
Published: November 2023

In most of the work described in the previous chapters, the universe has been treated as isotropic and homogeneous, with a gravitational field described by the Robertson–Walker metric. This is of course just an approximation, which ignores many of the most interesting things in the universe: galaxy clusters, galaxies, stars, us. We now turn to an analysis of these departures from homogeneity and isotropy.
Psychopathology and the ‘Methodenstreit’
Authors: Fulford K W M , Thornton Tim , Graham George
Published: November 2023

This is the second of two chapters concerned with the philosoph- ical basis of the work of Karl Jaspers. In Chapter 9 we consid- ered the influence of Edmund Husserl’s phenomenology, and concluded that there were aspects of Jaspers’ approach to psy- chopathology that were not ‘phenomenological’ in Husserl’s sense. These included the notions of ‘empathy’ and ‘imaginative re-living’, as parts of the psychopathologist’s methodology, and ‘understanding’ (as opposed to ‘explanation’) as a key aim of the psychopathologist’s investigations.
Tools of the trade: an introduction to psychiatric ethics
Authors: Fulford K W M , Thornton Tim , Graham George
Published: November 2023

Following the use-before-definition approach of Austin’s ‘philo- sophical fieldwork’, as developed in Part I, this chapter starts more or less straight in with practical case examples. We ask you to think about real situations, either from your general knowledge of mental health, or from your own experiences if you are a user or provider of services, and then to review the story of Mr AB, the man with depression treated on an involuntary basis introduced in Chapter 2.
Personal identity and schizophrenia
Authors: Fulford K W M , Thornton Tim , Graham George
Published: November 2023

This chapter looks at another central concept drawn from the philosophy of mind, which can both inform and be informed by psychopathology. The concept of personal identity is central to the subject matter of psychiatry. However, it also exemplifies the relationship between empirical and conceptual work that has run throughout this book. While psychopathology can teach us a great deal about what is involved in the nature of persons and our identity through time—and thus what can threaten that—there is no simple experiment available to answer the question: What is a person? Instead empirical evidence and conceptual exploration go hand in hand.
The visible universe
Authors: Rowan-Robinson Michael
Published: November 2023

Imagine that it is a clear moonless night in the country. The sky is ablaze with thousands of stars. The light from some of the faintest ones set out thousands years ago. In a great arc across the sky we see that familiar band of light, the Milky Way, which Galileo showed to be composed of myriads of faint stars. This is our own Galaxy, a discus-shaped metropolis of a hundred thousand million (1011) stars with ourselves far out towards the suburbs (see Fig. 1.1).
Our Galaxy and other galaxies
Authors: Rowan-Robinson Michael
Published: November 2023

The main constituents of galaxies are stars and interstellar gas and dust, and the main evolution of an isolated galaxy consists of stars condensing out of clouds of gas and dust, undergoing thermonuclear reactions, losing mass in winds from their surface, and finally either cooling down or dispersing much of their material in spectacular explosions. By tracing out the distribution of populations of stars of different ages in our Galaxy, we can get a good idea of the way that the Galaxy has evolved with time and what the last stages of its formation were like. Other types of galaxy can be explained as similar in structure to our own, and of the same age, but with differing star formation histories. Interactions and mergers between pairs of galaxies also play a significant part in the evolution of some, perhaps most, galaxies.
Other cosmological theories
Authors: Rowan-Robinson Michael
Published: November 2023

Firstly, we look at some of the problems of the General Relativistic Hot Big Bang models and the solution of these problems offered by the inflationary scenario. Then, for historical reasons we give an account of the steady state theory. We look at some theories of gravity in which the gravitational ‘constant’ G varies with time, and at anisotropic and inhomogeneous models within general relativity. We mention the cosmological implications of ‘grand unified’ theories, which attempt to unify the strong, electromagnetic, and weak forces of physics, and we discuss models which dispense with a hot big bang altogether.
Approaches to Visual Recognition
Authors: Ullman Shimon
Published: November 2023

Visual recognition is a task that the human brain performs effortlessly and efficiently, in a manner that far surpasses the ability of any artificial system or computational model proposed to date. Recognition can be performed at different levels of specificity, ranging from general classification to the identification of individual objects. For humans, classification is generally easier and more natural than individual identification. In contrast, current artificial systems typically cope significantly better with identification compared with general classification. In this chapter I review and compare leading theoretical approaches to visual recognition, focusing on visual classification. The chapter also discusses some of the main unsolved problems, as well as promising future directions.
Towards a Neural Basis of Human Visual Attention: Evidence from Functional Brain Imaging
Authors: Kastner Sabine
Published: November 2023

Attentional mechanisms are needed to select relevant, and to filter out irrelevant, information from cluttered visual scenes. Evidence from single- cell physiology studies in monkeys and functional brain mapping studies in humans indicates that selective attention modulates neural activity in the visual system. Attentional modulation is not confined to cortical processing, but occurs already in the lateral geniculate nucleus, which may serve as an early gatekeeper in attentional gain control. Atcortical processing stages, selective attention appears to operate by biasing interactions among multiple stimuli that compete for neural representation, thereby effectively filtering out irrelevant information from nearby distracters. Evidence in support of an attentional-load-dependent push–pull mechanism is reported that operates by facilitating responses evoked by attended stimuli and by suppressing responses evoked by unattended stimuli over large portions of the visual field.
The Role of Competitive Circuits in Extrastriate Cortex in selecting Spatially Superimposed stimuli
Authors: Reynolds John H , Fallah Mazyar
Published: November 2023

Extracellular recording studies of attention in monkeys trained to perform visual tasks find that changes in neuronal responses differ qualitatively depending on whether one or more stimuli appear within the neuron’s receptive field (RF). Attention to a single excitatory stimulus typically results in an increase in firing rate, regardless of whether the stimulus is a preferred or poor stimulus for the neuron. In contrast, attention to one of multiple stimuli within the RF can result either in increases or decreases in firing rate, depending on the neuron’s relative preference for the stimuli in the RF. These findings can be interpreted within the context of a psychological theory that relates them to psychophysical and functional imaging studies of attention in humans. This interpretation leads to specific predictions about changes in neuronal responses in an object-based attention paradigm.
Neural Selection and Control of Action
Authors: Schall Jeffrey D
Published: November 2023

This chapter is concerned with how perception guides action and with how actions are chosen and controlled to achieve goals. Human performance seems unexplainable without referring to unobservable processes such as encoding, categorizing, deciding, selecting, preparing, and monitoring. Neural correlates of each of these processes have been identified through both non-invasive and invasive monitoring methods. Indeed, single neurons can convey signals apparently sufficient to mediate these cognitive processes. A description of neural properties though, does not explain how the behavior and intermediate processes are produced. A complete explanation requires computational theories implemented in mathematical models.
Finite Elements and Fast Iterative Solvers: with Applications in Incompressible Fluid Dynamics
Authors: Elman Howard C , Silvester David J , Wathen Andrew J
Published: November 2023

The subject of this book is the efficient solution of partial differential equations (PDEs) that arise when modelling incompressible fluid flow. The material is organized into four groups of two chapters each, covering the Poisson equation (chapters 1 2); the convection-diffucion equation (chapters 3 4); the Stokes equations (chapters 5 6); and the Navier-Stokes equations (chapters 7 8). These equations represent important models within the domain of computational fluid dynamics, but they also arise in many other settings. For each PDE model, there is a chapter concerned with finite element discretization. For each problem and associated solvers there is a description of how to compute along with theoretical analysis which guides the choice of approaches. Illustrative numerical results occur throughout the book, which have been computed with the freely downloadable IFISS software. All numerical results should be reproducible by readers who have access to MATLAB and there is considerable scope for experimentation in the 'computational laboratory' provided by the software. This book provides an excellent introduction to finite elements, iterative linear solvers and scientific computing aimed at graduates in engineering, numerical analysis, applied mathematics and interdisciplinary scientific computing. Including theoretical problems and practical exercises closely tied with freely downloadable MATLAB software, this book is an ideal teaching and learning resource.
Solution of Discrete Convection-Diffusion Problems
Authors: Elman Howard C , Silvester David J , Wathen Andrew J
Published: November 2023

As shown in Chapter 3, the coefficient matrix arising from discretization of the convection-diffusion equation is nonsymmetric. To develop iterative solution algorithms for these problems, as well as those arising in other settings such as the Navier-Stokes equations, the algorithms discussed in Chapter 2 must be adapted to handle nonsymmetric systems of linear equations. In this chapter, we outline the strategies and issues associated with Krylov subspace iteration for general nonsymmetric systems, together with specific details for convection-diffusion systems associated with preconditioning and multigrid methods.
Basic concepts
Authors: Lindsey J K
Published: November 2023

The role of scientists is not simply to try to describe phenomena, but rather to explain them. From available knowledge, they develop scientific theories of why something happens and then make appropriate observations to check them. In turn, these observations can lead to modifications of the theory, which must also be checked, and so on. Scientific research involves a continual interaction between theory and empirical observation. Thus, a theory is constantly being checked, corrected, and improved in the light of new data; when this is no longer possible, it is replaced, but only if a better one is available.
Why is joint attention a pivotal skill in autism?
Authors: Charman Tony
Published: November 2023

Joint attention abilities play a crucial role in the development of autism. Impairments in joint attention are among the earliest signs of the disorder and joint attention skills relate to outcome, both in the ‘natural course’ of autism and through being targeted in early intervention programmes. In the current study, concurrent and longitudinal associations between joint attention and other social communication abilities measured in a sample of infants with autism and related pervasive developmental disorders at age 20 months, and language and symptom severity at age 42 months, were examined. Extending the findings from previous studies, joint attention ability was positively associated with language gains and (lower) social and communication symptoms, and imitation ability was also positively associated with later language.
A quick overview on the theory of integration
Authors: Ambrosio Luigi , Tilli Paolo
Published: November 2023

In this final chapter we make a brief excursus on the theory of integration, following a particularly elegant and original approach adopted by De Giorgi in 1983, in a series of unpublished lectures given in the Scuola Normale Superiore of Pisa see also De Giorgi and Letta 16] .
Why plantations?
Authors: Evans Julian , Turnbull John W
Published: November 2023

Interest in plantations and tree-planting in the tropics continues to increase rapidly. The area of plantation increased over thirteen times between 1965 and 2000, and the rate of planting in the 1990s was double that of the 1980s (Table 3.2). Why should this be so? Why should small countries such as Fiji, Swaziland, and Zimbabwe undertake plantation programmes covering tens of thousands of hectares, and why have millions of hectares being planted in China, India, and Brazil? In India, for example, not only are government and parastatal bodies involved but some 10 000 non-government organizations (NGOs) are concerned to promote tree-planting of one kind or another.
Social and economic factors in tree-planting and plantation development
Authors: Evans Julian , Turnbull John W
Published: November 2023

Development cannot bypass the lives of the people concerned whether they are directly involved as future employees on a plantation project or are those living nearby who see their familiar environment changed and new goods and services becoming available as a result of social forestry programmes. All development costs money, most developing countries are short of funds, and money raised from harvesting natural forests is frequently used to develop other sectors of higher national priority. This shortage often results in heavy reliance on official development assistance (ODA). Grayson (2000) notes that globally the flow of funds from rich to poor countries has been more than US$180 billion annually, of which ODA has been one-third and the balance has come from private sources. Of the US$60 billion of ODA only US$20 billion has come from multilateral agencies, the rest being from bilateral aid and national governments.
Plantation establishment
Authors: Evans Julian , Turnbull John W
Published: November 2023

Trees and forests are planted on many kinds of sites and this chapter is concerned primarily with three main ones: grassland, savanna, and recently cleared woodland or forest. Silvicultural techniques for where agroforestry is practised and on difficult sites, such as in arid and/or eroded lands, mining waste, and are considered elsewhere (Chapters 20 and 23). Nevertheless, a number of principles are common to all and much of this chapter is relevant to any plantation establishment regardless of site conditions.
High pruning
Authors: Evans Julian , Turnbull John W
Published: November 2023

In tropical tree plantations pruning is mainly carried out in two very different situations: to improve stem and wood quality in some industrial crops and as a tool in agroforestry and social forestry plantings, both to manipulate the trees to favour food crops, for example, in alley cropping, and to provide fodder, leaf mulch, fuel wood, smooth, snag-free poles, etc. Note that pruning in arboriculture and horticulture is to improve crown shape, stimulate flowering and fruiting, train branches, and sometimes simply for aesthetic purposes. This chapter primarily concerns high pruning in industrial plantations; Chapters 18, 20–21, and 23 make further reference to pruning practices in agroforestry and rural development forestry including pollarding.
Afforestation of inhospitable sites
Authors: Evans Julian , Turnbull John W
Published: November 2023

It is very difficult to grow trees on some sites, but only in a few environments with extreme cold or no soil is it completely impossible. Apart from these environments, with careful treatment of the site and correct choice of species, trees can be established on many very unpromising sites. Although some species are remarkably tolerant of poor growing conditions, establishing trees on naturally inhospitable sites usually requires special techniques. This chapter outlines the reasons which make sites inhospitable and considers the silvicultural techniques for afforesting five examples: arid-zone areas; steep and eroding slopes; man-made, industrial waste ground; saline and sodic soils; and mangroves.
A journey from neocortex to hippocampus
Authors: Bliss T V P
Published: November 2023

In the mid-1960s, it was generally agreed that the engram, the neural trace of previously experienced events, must be encoded by Hebb-like neurons in which synaptic efficacy could be modified by activity. Here, I describe my attempts as a PhD student at McGill University, Montreal, to find rules governing cortical plasticity in the neocortex, and having failed, why the hippocampus seemed to offer a far better prospect. Sometime in the autumn of 1963 I went to see Ben Delisl Burns, then a professor in the Physiology Department at McGill University, Montreal, where I had taken my undergraduate degree, to talk about doing a PhD with him.
Active dendrites, potassium channels and synaptic plasticity
Authors: Johnston Daniel , Christie Brian R , Frick Andreas , Gray Richard , Hoffman D A , Schexnayder Lalania K , Watanabe Shigeo , Yuan Li-Lian
Published: November 2023

The dendrites of CAI pyramidal neurons in the hippocampus express numerous types of voltage-gated ion channels, but the distributions or densities of many of these channels are very non-uniform. Sodium channels in the dendrites are responsible for action potential (AP) propagation from the axon into the dendrites (back-propagation); calcium channels are responsible for local changes in dendritic calcium concentrations following back-propagating APs and synaptic potentials; and potassium channels help regulate overall dendritic excitability.
Long-term potentiation in the dentate gyrus of the anaesthetized rat is accompanied by an increase in extracellular glutamate: real-time measurements using a novel dialysis electrode
Authors: Errington M L , Galley P T , Bliss T V P
Published: November 2023

We have used a glutamate-specific dialysis electrode to obtain real-time measurements of changes in the concentration of glutamate in the extracellular space of the hippocampus during low-frequency stimulation and following the induction of long-term potentiation (LTP). In the dentate gyms, stimulation of the perforant path at 2 Hz for 2 min produced a transient increase in glutamate current relative to the basal value at control rates of stimulation (0.033 Hz). This activity-dependent glutamate current was significantly enhanced 35 and 90 min after the induction of LTP.
Long-term potentiation and the ageing brain
Authors: Barnes C A
Published: November 2023

Ageing is associated with learning and memory impairments. Data are reviewed that suggest that age-related impairments of hippocampal-dependent forms of memory, may be caused, in part, by altered synaptic plasticity mechanisms in the hippocampus, including long-term potentiation (LTP). To the extent that the mechanisms responsible for LTP can be understood, it may be possible to develop therapeutic approaches to alleviate memory decline in normal ageing.
Genetic neuroscience of mammalian learning and memory
Authors: Tonegawa Susumu , Nakazawa Kazu , Wilson Matthew A
Published: November 2023

Our primary research interest is to understand the molecular and cellular mechanisms on neuronal circuitry underlying the acquisition, consolidation and retrieval of hippocampus-dependent memory in rodents. We study these problems by producing genetically engineered (i.e. spatially targeted and/or temporally restricted) mice and analysing these mice by multifaceted methods including molecular and cellular biology, in vitro and in vivo physiology and behavioural studies. We attempt to identify deficits at each of the multiple levels of complexity in specific brain areas or cell types and deduce those deficits that underlie specific learning or memory. We will review our recent studies on the acquisition, consolidation and recall of memories that have been conducted with mouse strains in which genetic manipulations were targeted to specific types of cells in the hippocampus or fore-brain of young adult mice.
MAPK, CREB and zif268 are all required for the consolidation of recognition memory
Authors: Bozon Bruno , Kelly Aine , Josselyn Sheena A , Silva Alcino J , Davis Sabrina , Laroche Serge
Published: November 2023

There has been nearly a century of interest in the idea that encoding and storage of information in the brain requires changes in the efficacy of synaptic connections between neurons that are activated during learning. Recent research into the molecular mechanisms of long-term potentiation (LTP) has brought about new knowledge that has provided valuable insights into the neural mechanisms of memory storage. The evidence indicates that rapid activation of the genetic machinery can be a key mechanism underlying the enduring modification of neural networks required for the stability of memories.
Representations of astrolabes in Western art
Authors: Cleempoel Koenraad Van
Published: November 2023

The relatively infrequent depiction of astrolabes in works of art seems disproportionately small in relation to the large amount of instruments that have survived and to the high number of contemporary treatises that discuss the astrolabe. In comparison, its three-dimensional counterparts – the armillary sphere, and the celestial and the terrestrial globe – have experienced wider acclaim from artists throughout the ages. The immediate ornamental and didactic appeal of these other instruments may be responsible for this trend. But also, in a broader sense, the image of the globe and the armillary sphere became a popular visual metaphor for disciplines such as geometry and astronomy, where they are still used until the present day.
Fibre bundles
Authors: Kawakubo Katsuo
Published: November 2023

Given two topological spaces X and Y, the construction of the Cartesian product X × Y is a method of constructing new topological spaces out of old. A generalization of this Cartesian product is the notion of fibre bundles, which have the Cartesian product structures locally. Its definition is given in terms of transformation groups; hence one may say that the theory of fibre bundles is an application of the theory of transformation groups.
Manifolds and Lie groups
Authors: Kawakubo Katsuo
Published: November 2023

The aim of this chapter is to provide an introduction to the theory of differentiable manifolds and Lie groups.

The Euclidean space ℝ is the most important space in mathematics in general; for example, differential calculus is performed extensively on Euclidean space. It is natural enough that we are then led to study those spaces which are locally like ℝ, and more precisely those spaces in which each point has a neighbourhood homeomorphic to ℝ. We call such spaces manifolds.
Solution of a Classical Problem on Finite Inversive Planes
Authors: Thas J A
Published: November 2023

Let Ibe a finite inversive plane of odd order q, qr/.{11, 23,59). If for at least one point pof Ithe internal affine plane Ipis Desarguesian, then Iis Miquelian. Other formulation: for q (/.{11,23,59) the finite Desarguesian affine plane of odd order qhas a unique extension; this extension is the Miquelian inversive plane of order q.As a direct corollary we obtain a computer-free proof of the uniqueness of the inversive plane of order 7.Let Cbe a circle of the inversive plane I,let pE Cand let pbe a point not on C.Since Ipis an affine plane it follows that there is a unique circle C’ through pand pwhich has only pin common with C.We say that the circles C1 and C2 are tangentif C1 = C2 or IC1 n C2I = l. Now it is clear that tangency is an equivalence relation on the set of all circles. If Ois an ovoid[7] of PG(3, q), then the points of Otogether with the intersections 1rnO, with ,r a non-tangent plane of O,form an inversive planeof order q.Such an inversive plane is called egglike.For an egglike inversive plane Ieach internal plane Ipis Desarguesian. By a celebrated theorem of P. Dembowski [7] each finite inversive plane of even order is egglike. If the ovoid Ois an elliptic quadric, then the corresponding inversive plane is called classicalor Miquelian.By a celebrated theorem of A. Barlotti [14] each egglike inversive plane of odd order is Miquelian.
First-Order Partial Differential Equations
Authors: Collins Peter J
Published: November 2023

This chapter considers the equation where p, q denote the partial derivatives of the real-valued function z = z(x, y) and P, Q, R are continuous real-valued functions of r = (x, y, z) in an appropriate domain in ℝ3. The equation is linear in p, q and quasi-linear because, in addition, P, Q, R are functions of z as well as of x and y. We search for real-valued solutions z = z(x, y) of (1). It is often useful to visualise our methods geometrically, and we shall refer to such solutions, because of the objects they represent, as solution surfaces. There is one important picture to hold in one’s mind, and this is illustrated in section 5.5, where it forms an integral part of our discussion. Otherwise, our aim is to encourage the reader’s analytic intuition. The main problem, the Cauchy problem, is to discover whether there is a unique solution surface which contains (‘passes through’) a given ‘boundary’ curve. This is in general not possible and when it is, there is usually a restriction to be placed on the domain of the independent variables x, y in order that such a unique solution exists. The restricted domain is called the domain of definition of the solution.
Iterative Methods and Neumann Series
Authors: Collins Peter J
Published: November 2023

In this chapter we take a new look at the iterative method introduced in Chapter 1. Our goal will be to introduce the Neumann series, the terms of which involve iterations of the kernel of an integral equation, and use this series to derive the solution of the equation. Throughout the chapter we shall be concerned solely with the non-homogeneous Fredholm equation where K and f are real-valued continuous functions and λ is a constant. The kernel K = K(x, t) need not be symmetric. We first suggest that the reader review Picard's method as used in section 1.2 to solve the non-homogeneous Fredholm equation. We now introduce a simple example to which we shall return at various points in this chapter. It is used here to continue the review of Picard's method and will also be used to exemplify the new procedures which will appear later.
The Sturm–Liouville Equation
Authors: Collins Peter J
Published: November 2023

This chapter concerns the homogeneous equation where p : [a, b] → ℝ is continuously differentiable, q : [a, b] → ℝ and ⍴: [a, b] → ℝ are continuous, p(x) > 0 and ⍴(x) > 0, for all x in [a, b], and λ is a real constant. The equation generalises (H) of section 4.2 and L denotes the operator that was defined in that section. Further, we shall impose the same homogeneous boundary conditions, namely: where A  1, A  2, B  1, B  2 are constants (A  1, B  1 not both zero and A  2, B  2 not both zero). A value of the constant λ, for which (SL), together with (α) and (β), has a solution y = y(x) which is not identically zero on [a, b], is called an eigenvalue of (SL), (α), (β), and such a non-zero solution y = y(x) is called an eigenfunction of (SL), (α), (β) (‘corresponding to the eigenvalue λ’). Our discussion will bring together much of the work in earlier chapters, from Green's functions, the correspondence between integral and differential equations and the existence-uniqueness theorems for the latter, to the use of the Calculus of Variations, of the Fredholm Alternative Theorem and of the Expansion Theorem for symmetric kernels. We should like to stress the importance of the material in this chapter for applications, especially in physics. The Note following Exercise 5 below gives an important example. Others can be found via the list of references in the Bibliography.
Series Solutions
Authors: Collins Peter J
Published: November 2023

In this chapter, we investigate a special technique which provides solutions to a wide class of differential equations. Again, we concentrate on the homogeneous linear second-order equation where p  0, p  1, p  2 are continuous functions which we shall suppose throughout this chapter to have no common zeros. We do not, for the moment, specify the domain of these functions, though it will in general be taken to be an interval, finite or infinite. Hitherto, we have often specified that the function p  2 is never zero. A point x  0 in the domain of p  2 for which p  2(x  0) ≠ 0 is called an ordinary point of the differential equation (1). We shall discuss how solutions y to (1) in a neighbourhood of an ordinary point x  0 can, in rather general circumstances, be represented as a power series For example, the geometric series convergent for |x| < 1, is the solution of the equation satisfying y(0) = y′(0) = 1, in the open interval (–1; 1) about the ordinary point 0. The reader can easily check this by first noting that the series solution (2) can be represented in (–1; 1) in the closed (or finite) form.
Project 12
Authors: Grandine Thomas A
Published: November 2023

ACME’s new Humble Automatic Lackey 9000, an industrial robot (also mentioned in Project 1), has not been as reliable as the competition’s robot, i.e. AJAX’s Newfangled Electronic Robotic Device. The main difficulty is that the arm movement is not smooth and this has placed undue strain on the various joints and mechanisms. Because of your reputation as a trouble-shooter you have been asked to investigate this problem.
Project 22
Authors: Grandine Thomas A
Published: November 2023

The Modern Electronic Lifting Team, a division of ACME, is designing a grabber arm for the Humble Automatic Lackey 9000, ACME’s industrial robot (mentioned in Project 1 and Project 12). The grabber arm is intended to enable HAL to grab objects which are much too hot for him to grab directly. Because the competition from the AJAX Newfangled Electronic Robotic Device (mentioned in Project 12) is so stiff, MELT needs to minimize its costs as much as possible when designing and building the grabber arm. MELT has asked SOLVE for assistance with this design problem, and Biro Kratt has decided that the problem is important enough to warrant putting his best person on the project, so you have been asked to help out. The main component of the grabber arm is a metal dowel made up of a mixture of two alloys, namely insulatinum and conductivitum. One end of the dowel will be exposed to temperatures as high as 850 K, while the other end will be attached directly to HAL, who cannot tolerate temperatures in excess of 375 K without suffering thermal circuitry failure. You have been asked to design the MELT dowel so that HAL does not fail.
Ordinals
Authors: Potter Michael D
Published: November 2023

The simple and general principles of induction are powerful tools for proving things about the natural numbers: we intend now to investigate ways in which they can be generalized to apply to a very much wider class of ordered collections than the subsets of ro. The basis of our study will be the observation that the general principle of induction follows trivially from the least element principle and can therefore be applied to any ordered collection which shares this property: we call such collections ‘well ordered’. Our strategy will be to apply the same techniques to the study of isomorphism between well ordered sets as we used in Chapter 4 to investigate equinumerosity between sets: just as the work of Chapter 4 produced an arithmetic of cardinals, in this chapter we shall get an arithmetic of ordinals.
Elementary Categories, Elementary Toposes
Authors: McLarty Colin
Published: November 2023

The book covers elementary aspects of category theory and topos theory. It has few mathematical prerequisites, and uses categorical methods throughout rather than beginning with set theoretic foundations. It works with key notions such as cartesian closedness, adjunctions, regular categories, and the internal logic of a topos. Full statements and elementary proofs are given for the central theorems, including the fundamental theorem of toposes, the sheafification theorem, and the construction of Grothendieck toposes over any topos as base. Three chapters discuss applications of toposes in detail, namely to sets, to basic differential geometry, and to recursive analysis.
Introduction
Authors: McLarty Colin
Published: November 2023

Eilenberg and Mac Lane created categories in the 1940s as a way of relating systems of algebraic structures and systems of topological spaces in algebraic topology. The spread of applications led to a general theory, and what had been a tool for handling structures became more and more a means of defining them. Grothendieck and his students solved classical problems in geometry and number theory using new structures —including toposes — constructed from sets by categorical methods. In the 1960s, Lawvere began to give purely categorical definitions of new and old structures, and developed several styles of categorical foundations for mathematics. This led to new applications, notably in logic and computer science.
External semantics
Authors: McLarty Colin
Published: November 2023

We have interpreted formulas in a topos E by assigning each an extension. This is called the internal semantics. The external semantics, also called Kripke-Joyal semantics, describes which generalized elements satisfy each formula. The idea is that the extension collects the instances of a formula internally to E, while the class of generalized elements satisfying it is an external collection. A generalized element satisfies a formula iff it is a member of the formula’s extension, and this external viewpoint is often handy for more complicated formulas.
Categories in a topos
Authors: McLarty Colin
Published: November 2023

In this chapter small categories and functors in a topos E are defined. Functors are then defined from a small category A to E, and the category EA of such functors, and it is proved that £A is a topos. Examples of functor categories on the topos Set are given in Chapter 22. Section 20.l really only applies naive constructions given in Part II to small categories in E. It generalizes the results in Chapter 12 on small categories in a universe of sets.
Mesh Data Surface Fitting
Authors: Dierckx Paul
Published: November 2023

In this chapter we will present efficient methods for calculating least-squares or smoothing splines if the data values are specified at the nodes of a rectangular mesh. We will also explore a number of possibilities of using these methods in case the latter condition is not (completely) satisfied or in case we are faced with extremely large data sets which necessitate a piecemeal treatment.
Definability
Authors: Borovik Alexandre , Nesin Ali
Published: November 2023

We need very little from model theory: just two concepts, and no real results, not even the compactness theorem. The concepts, definability and interpretability, are dealt with in this chapter and the next.