bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Properties
Authors: Seshadri V
Published: November 2023

The numerous distributional properties discussed in Chapter 2 and the important role played by the inverse Gaussian law in the study of exponential families motivate a survey of the development of statistical methods of in ference based on this law. The usefulness of this law in applied work has had a modest beginning with the estimation methods of Schrodinger, and the pioneering works of Halphen and Tweedie. We review some basic statistical theory and methodology concerned with this law. We shall, however, desist from analysing data sets, focusing attention only on theoretical issues. The reader is assumed to be familiar with a reasonably good background of mathematical statistics.
Norms of redress
Authors: Richard DeRidder , Kumar Rashmi , Schruijer Sandra G L
Published: November 2023

The issue we will address in this chapter is related to the second finding. Are the relatively positive reactions to the other group member’s norm violation due to the respondents’ desire to convey a positive impression of themselves on the investigator? This would mean that the reactions subjects gave in the questionnaires were biased by social desirability. It could also be, and this is the argument we will elaborate in this chapter, that their responses stemmed from shared opinions about the most appropriate reactions in instances where norm violation by one group may trigger a conflict. In other words, it will be argued, and studied empirically, that in groups, such as Hindus and Muslims, certain ‘norms of redress’ exist that stipulate how group members should react in situations in which another group starts a possible escalation of negative intergroup behaviour by violating a norm.
Representation of visual stimuli in inferior temporal cortex
Authors: Gross Charles G
Published: November 2023

In primates, inferior temporal (IT) cortex is crucial for the processing and storage of visual information about form and colour. This article reviews the properties of IT neurons and considers how these properties may underlie the perceptual and mnemonic functions of IT cortex. The available evidence suggests that the processing of the facial image by IT cortex is similar to its processing of other visual patterns. Faces and other complex visual stimuli appear to be represented by the pattern of responses over a population of IT neurons rather than by the responses of specific ‘feature detectors’ or ‘grandmother’ cells. IT neurons with adult-like stimulus properties are present in monkeys as young as six weeks old.
Modelling face recognition
Authors: Bruce Vicki , Burton A Mike , Craw Ian
Published: November 2023

Much early work in the psychology of face processing was hampered by a failure to think carefully about task demands. Recently our understanding of the processes involved in the recognition of familiar faces has been both encapsulated in, and guided by, functional models of the processes involved in processing and recognizing faces. The specification and predictive power of such theory has been increased with the development of an implemented model, based upon an ‘interactive activation and competition’ architecture. However, a major deficiency in most accounts of face processing is their failure to spell out the perceptual primitives that form the basis of our representations for faces. Possible representational schemes are discussed, and the potential role of three-dimensional representations of the face is emphasized.
Regression, Sequenced Measurements and Coherent Calibration
Authors: Brown P J , Mäkeläinen T
Published: November 2023

We use the tractable Normal-Inverted-Wishart prior distribution to assign prior structure to q + 1 variables. It is desired to predict one variable, the response, from the other q variables coherently with respect to varying q. Here we consider situations where these q variables are realistically a subsample from a continuous process. In this context we introduce the notion of structural coherence. Application is to spectroscopic analysis of a mixture where each datum is a spectral curve.
Reconciling Costs and Benefits in Experimental Design
Authors: Farrow M , Goldstein M
Published: November 2023

We consider the design of experiments, the objective of which may be to learn about the values of several different quantities and which may involve costs of more than one type. In particular, medical experiments may give information on several different quantities and will generally involve ethical costs as well as financial costs. Experimenters may be unwilling to specify explicit trade-offs, for example between information gained and costs or between financial and ethical costs. We suggest an approach to exploring the set of possible designs and presenting the results of this exploration in a way that may help those who must choose the design to come to a decision. The degree 0f detail necessary in the prior belief specification depends upon the assumptions that can be made about the form of an underlying utility function. We illustrate our approach with a medical example.
Multiobjective Bayesian Bandits
Authors: Jones P W
Published: November 2023

Modifications of the Bernoulli two armed bandit with finite horizon and independent beta priors are discussed. A terminal decision rule and a stopping rule are introduced. Optimal sequential designs and their characteristics are derived using a series of recurrence relations. The effects of changes in prior information are studied.
Bayesian Parametric Models for Lifetimes
Authors: Mendel Max B
Published: November 2023

The paper develops a systematic procedure for constructing probability models for unit lifetimes. It identifies the smallest class of such models that suffice for selecting a cost-optimal maintenance or operating policy. Lifetime-cost functions are introduced, replacing the classical failure rate functions for specifying model classes. It is shown how these classes can be represented through Bayesian parametric models. To illustrate, several common lifetime models and their finite population analogs are derived, including the exponential, the Weibull, Freund’s multivariate exponential, and a new multivariate Weibull.
Bands of Probability Measures: a Robust Bayesian Analysis
Authors: Moreno Elías , Pericchi Luís R
Published: November 2023

This class allows considerable freedom on tail behaviour as long as the upper and lower measures L, U have different tails. This property is inherited from the class of interval of measures (DeRobertis and Hartigan, 1981), from which probability bands are obtained by restricting attention to those measures that integrate to one. Although the analysis of this restricted class is somewhat more involved, the restriction is quite natural and may lead to much smaller posterior ranges of the quantities of interest. General results for this model and some illustrations for two dimensional likelihoods are given. Comparison with interval of measures are also made.
Growth variation and comparative growth homeostasis
Authors: Brush G
Published: November 2023

Introduction

This chapter is a suffilllary of recent attempts to analyse variation in growth. The purpose is not to tabulate variance nor to use it to quantify statistical uncertainty, but to describe how variation accumulates during the process of growth. The results will indicate that a portion of the environmental contribution to growth variation is expected to accumulate in a distinctive pattern. This pattern will be modelled in an attempt to quantify the interaction between environmental conditions which disrupt growth and the ability of homeostatic mechanisms to compensate.
Mother’s morale and infant health in Ethiopia
Authors: Almedom A M
Published: November 2023

Previous studies have examined infant health in relation to nutritional status and physical growth performance. Studies which demonstrated the complexities of the relationships, particularly those between nutrition and morbidity, some more than two decades ago, continue to influence current research (Scrimshaw et al. 1968, 1969; Mata et al. 1977, Mata 1978; Tomkins 1981; 1986; Black et al. 1984; Tomkins and Watson 1988; Aaby 1988; Ulijaszek 1990). Malnutrition makes infants susceptible to infection and infection leads to the failure to make effective use of nutrients and thus leads to malnutrition.
Inside the gurrnganngara: social processes and demographic genetics in north-east Arnhem Land, Australia
Authors: White N G
Published: November 2023

The Yolngu today number approximately 3200 and occupy an area of about 26000 square kilometres, bounded by coastline to the north and east and river systems to the south and west (Fig. 14.1). These people, referred to variously as Murngin, Wulamba, and Malag, as well as Yolngu, are the subject of a substantial social anthropological literature, much of it relating to their complex social organization and religion, including art and ritual (see for example Warner 1937; Thomson 1949; Berndt 1951, 1952; Williams 1986; Morphy 1991).
Community sentences and the work of the Probation Service
Authors: Hine Jean
Published: November 2023

On 1 January 1991, there were 138 721 offenders currently under the supervision of the Probation Service. During 1991, 129 463 offenders commenced a period of community supervision or post-custodial licence with the service. These figures from Probation Statistics England and Wales 1991 show that well over a quarter of a million offenders were subject to supervision by the Probation Service at some time during that year, a volume often not appreciated by people outside the service.
Parole
Authors: Ditchfield John
Published: November 2023

The 1965 White Paper ‘The Adult Offender’ proposed that prisoners who had shown promise or determination to reform should be able to earn a further period of freedom on parole (i.e. over and above the one-third remission they already earned) of up to one-third of sentence. It argued that: Prisoners who do not of necessity have to be detained for the protection of the public are in some cases more likely to be made into decent citizens if, before completing the whole of their sentence, they are released under supervision with a liability to recall if they do not behave ... What is proposed is that a prisoner’s date of release should be largely dependent upon his response to training and his likely behaviour on release. A considerable number of long-term prisoners reach a recognisable peak in their training at which they may respond to generous treatment, but after which, if kept in prison, they may go downhill.
Ethnic differences
Authors: Fitzgerald Marian
Published: November 2023

The book was seminal in comprehensively raising issues about racial prejudice, discrimination, and disadvantage, a key reference source for groups campaigning for government action on these problems. Yet when official statistics on ‘race’ and crime began to enter the public domain some ten years later, the response of these groups was ambivalent. The publication in 1982 by the Metropolitan Police Commissioner of figures selected to show an over-representation of black offenders in street crime relative to their presence in the population at large was roundly condemned; yet the same data sources were used by the black-led ‘scrap sus’ campaign to demonstrate discrimination by the police (Demuth 1978).
Input and output
Authors: Payne R W , Lane P W , Digby P G N , Harding S A , Leech P K , Morgan G W , Todd AD , Thompson R , Wilson G Tunnicliffe , Welham S J , White R P
Published: November 2023

This chapter describes how to read data values into Genstat and how to print them out. It also looks at some of the more general aspects of input and output, such as the use of files for storing different kinds of information.

As already mentioned (1.1), Genstat statements may be typed in at the keyboard or stored in files and executed as a complete program. Similarly, data can be typed in directly or read, from files that have been prepared in advance. Many directives produce output that can either be displayed on the screen or stored in output files. Usually Genstat programs, data, and output are stored in character files. These are easily manipulated by other programs, such as text editors or word processors; so they can easily be viewed or modified on the screen of the PC or terminal, or printed out if hard copy is required.
Graphical display
Authors: Payne R W , Lane P W , Digby P G N , Harding S A , Leech P K , Morgan G W , Todd AD , Thompson R , Wilson G Tunnicliffe , Welham S J , White R P
Published: November 2023

Genstat can produce graphical output in two distinctively different styles. These are line printer graphics and high-resolution graphics. As the name suggests, line-printer graphics are designed for printing on ordinary printers, and are also suitable for display on terminals and 4PC screens. The standard character set, made up of letters, digits, and punctuation characters, is used to produce a graphical representation of the data. This will be of low resolution, typically 24 rows by 80 columns for screen display, 132 by 48 or 80 by 60 for a printer; but this is quite adequate for many uses within Statistics, such as producing a scatterplot or histogram of raw data or checking the distribution of residuals. The advantage of this form of output is that no special equipment, such as a graphics terminal or plotter, is required; also the graphics form an integral part of the Genstat output, and can thus be interspersed with other results during the analysis of your data. Histograms, graphs, and contour plots can be produced in this basic style.
Population genetic studies on national minorities in China
Authors: Omoto Keiichi , Hirai Momoki , Harihara Shinji , Misawa Shogo , Washio Keiko , Tokunaga Katsushi , Saitou Naruya , Yamazaki Kentaro , Du Ruofu , Hao Luping , Yuan Yida , Xu Jiujin , Jin Feng , Hu Jiaoyu , Wei Xierong , Li Shizhe , Zhao Hong , Zhang Zhi , Niu Keyi , Du Chuanshu , Liu Bao
Published: November 2023

From 1985 to 1991 we carried out a joint Japanese-Chinese population genetic study on national minority groups in China. At least 55 such groups are registered in China, and it is clearly impossible to sample most of these groups in 6 years. We therefore planned to concentrate only on groups living in eastern China. The reason for this choice is that we intended to clarify the genetic origins of the Japanese.
The emerging field of human rights statistics
Authors: Jabine Thomas B
Published: November 2023

The scientific-statistical analysis of human rights appears at first unnecessary and harmful. One murder for political ends is too many; one starved child for political ends is too much. Nevertheless, there is an emerging field of human rights statistics. And a bit of thought can justify the need for the statistics.
Periodic and rolling samples and censuses
Authors: Kish Leslie
Published: November 2023

Table 1 lists the major types of population surveys now conducted in the USA and in many industrialized countries. Some of these are conducted even more widely, and decennial censuses cover most countries today. I refer here to population surveys of persons, families, households, and dwellings, also to characteristics and variables based on them. As for surveys of other populations – of agriculture, industry, commerce – we shall mention them in the next section, as well as other types of surveys. The surveys listed here are mostly repeated and periodic, and mostly done by the government; in the USA mostly by the US Bureau of Census (USBC). They are mostly national surveys, though others may be regional or even local in scope; or cover only some subpopulation.
Scientific Inference and Predictions; Multiplicities and Convincing Stories: A Case Study in Breast Cancer Therapy¹
Authors: Berry² D R , Thor A , Cirrincione C , Edgerton S , Muss H , Marks J , Liu E , Wood W , Budman D , Perloff M , Peters W , Henderson I C
Published: November 2023

The Bayesian approach has great potential for contributing methodology and ways of thinking about scientific inferences. In theory the Bayesian approach is elegant and easy: Apply Bayes’ theorem. And recent calculational advances allow for finding posterior and predictive distributions that were once intractable. However, most scientific inferences and decision problems involve multiplicities and other complications. Assessing one’s prior distribution and specifying likelihood models are not easy in the presence of multiplicities. Assessment is especially difficult when there are disparate sources of information-such as when different experiments use treatment variations and when the experimental units are themselves different. We discuss the role of discovery and prediction in science and describe a subjective process of evaluating data-based hypotheses. Any model-such as one we give-that captures the essence of a data-based hypothesis is questionable.
Bayesian Histograms
Authors: Hartigan J A
Published: November 2023

A histogram is a density talking a finite number of values. In a Bayesian setting, we consider various prior distributions over the set of possible histograms, which permit convenient computation of the posterior distribution over histograms given the data. How can a single summary histogram be selected from this posterior distributionã The obvious density estimate is the average posterior histogram density at each point, but this estimate is not in general a histogram, even if the prior distribution is over histograms. One possibility for a single summary histogram is the mode of the posterior distribution over histograms; another is the envelope histogram with the maximum number of cells such that every horizontal segment intersects both the 95% envelope and the 5% envelope of the histogram densities. The envelope histogram conveys information about both the estimate and the variability of the estimate at each point; we can use it, for example, to make quantitative assertions about the presence of more than one mode. We consider a class of Bayesian histograms that are location and scale invariant; the same relative inference about densities is made in any interval, given the same relative distribution of observations in the interval. Histograms and density estimates of this type are compared with histograms of equal cell sizes in a number of data sets.
A Note on Histogram Approximation in Bayesian Density Estimation
Authors: Andreev A , Arjas E
Published: November 2023

In Bayesian density estimation, it is in practice necessary to restrict the space of density functions in some way, in order to arrive at an effectively finite parametrization. Here we consider piecewise constant functions as an approximating family. We show that if such functions are used to support an approximation of the “true” prior, then, under a set of natural conditions, the corresponding approximation will hold for the posterior.
A Comparison of Sequential Learning Methods for Incomplete Data
Authors: Cowell* R G , Dawid* A P , Sebastiani** P
Published: November 2023

Deterministic and stochastic methods to approximate a mixture distribution which arises in learning with incomplete data are compared in a simple problem. Simulation results suggest that a simple deterministic method based on moment matching gives a very good approximation of the exact mixture distribution. This also works well when combined with an initial stochastic updating.
Spherically Symmetric Bayes Estimators for a Linear Subspace of a Normal Law
Authors: Fourdrinier* D , Wells** M T
Published: November 2023

The theory of Bayesian least squares for the normal law is developed for priors supported on a linear subspace of the parameter space. We assume that a spherically symmetric distribution is used as a prior in conjunction with normal sampling distribution. In order to underline the intrinsic aspect of our results, the coordinate-free approach is adopted. Examples which illustrate the theory are presented.
Stochastic Deformable Templates and Object Tracking
Authors: Phillips D B , Smith A F M
Published: November 2023

Bayesian analyses of complex structures in images using sophisticated deformable shape models are rendered possible by recent advances in Markov chain Monte Carlo methodology. We consider extending the templates into a dynamic setting to allow for object tracking in image sequences. Our method combines a well-known analytic approach to non-linear dynamic modelling, the extended Kalman filter, with MCMC algorithms designed to sample object templates from suitably-defined likelihood functions. The approach is illustrated using some real face image sequences, where the aim is to track the face and predict its next position.
Graphical Methods for Simulation-Based Bayesian Inference
Authors: Vounatsou P , Smith A F M
Published: November 2023

We suggest graphical methods for summarizing simulation-based outputs for the purpose of inference, with emphasis on Bayesian hypotheses testing, model comparison and criticism. We discuss the application of some well-known graphical methods of exploratory data analysis to simulation-based Bayesian inferences and, in particular, we test hypotheses about mean/variance equality of several normal and multinormal populations.
Building, drawing and ‘artificial perspective’
Authors: Field J V
Published: November 2023

To the twentieth-century eye, correct perspective seems an obvious contribution to making a picture more naturalistic. However, the invention of mathematical rules for this purpose does not seem to have a direct link with the increased naturalism which is a feature of the painting of the fourteenth century. It was not a painter who invented a method of showing objects exactly in accordance with the laws of optics: Brunelleschi was, as we have already noted, trained as a gold smith, and he was, as far as we know, never a member of the guild that painters belonged to, namely that of the Physicians and Apothecaries (Medici e Speziali), or of the painters’ confraternity, the Company of St Luke (Compagnia di San Luca).
Comparing Curves and Surfaces
Authors: Bowman Adrian W , Azzalini Adelchi
Published: November 2023

In Chapter 4 some simple inference was carried out by assessing whether a covariate had any effect on a response. In Chapter 5 the special case of comparing nonparametric and parametric models was discussed. This topic was also mentioned in Chapter 2 where a normal shape for densities was considered. In this chapter nonparametric models for different groups of data are compared. Both density estimates and nonparametric regression curves are considered.
Convergence to equilibria for fluid models of certain FIFO and processor sharing queueing networks
Authors: Bramson Maury
Published: November 2023

The qualitative behavior of open multiclass queueing networks is currently a topic of considerable activity. An important goal is to formulate general criteria for when such networks possess equilibria, and to characterize these equilibria when possible. Fluid models have recently become an important tool for such purposes. We are interested here in two families of such models. The first consists of FIFO fluid models of Kelly type, that is, the discipline is first-in, first-out, and the service rate depends only on the station. The second consists of a family of processor sharing fluid models, where the fraction of time spent serving a class present at a station is proportional to the quantity of the class there, and all of the service goes into the “first customer” of each class. We refer to members of this second family as head-of-the-line proportional processor sharing (HLPPS) fluid models. To study both families of models, we introduce entropy functions associated with the states of the systems. Appropriate estimates show that for both families, if the traffic intensity function is at most 1, then the fluid models converge exponentially fast to equilibria with fixed concentrations of customer types at each queue. When the traffic intensity function is strictly less than 1, the limit is always the empty state and occurs after a finite time. A consequence is that generalized Kelly and HLPPS networks with traffic intensity strictly less than 1 are positive Harris recurrent, and hence possess unique equilibria. The results for FIFO models presented here are demonstrated in Bramson (1996a); the results for HLPPS models will appear in Bramson (1996b).
Optimal draining of fluid re-entrant lines: some solved examples
Authors: Weiss Gideon
Published: November 2023

In a fluid re-entrant line fluid moves in sequence through buffers 1, ... , K which are partitioned between I machines. Each machine can divide its effort continuously between the buffers it serves and flow rates out of the buffers are proportional to the effort. It is desired to find flow rates over period (0, T) that empty the line with minimum average inventory, equivalently cycle time. This formulation is a first approximation to a transient re-entrant line queueing network, which in turn models many industrial processes, e.g. semiconductor wafer fabrication. The problem can be formulated as a continuous linear program, with a very special structure. In this paper we discuss some properties of the optimal solutions, and these properties enable us to solve several examples. The solutions themselves are quite instructive. We also outline some ideas for an efficient algorithm to solve the problem.
Queue lengths and departures at single-server resources
Authors: Connell Neil O’
Published: November 2023

In this paper I will review and illustrate some large deviation results for queues with interacting traffic, both for shared buffer and shared capacity models. These results are examples of a general scheme which can be applied to an endless variety of network problems where the goal is to establish probability approximations for aspects of a system (such as queue lengths) under very general ergodicity and mixing assumptions about the network inputs.
Nonparametric estimation for quantities of interest in queues
Authors: Pitts Susan M
Published: November 2023

Various techniques from nonparametric statistics may be applied to stochastic models. The theoretical results are summarized here, and their application is illustrated with reference to the GI /GI /1 queue. Suppose that a particular queueing situation is modelled by an M(λ.)/M(μ)/1 queue. A common procedure in practice is to derive estimators for the parameters λ and μ from observations of the arrival and service times. Depending on the purpose of the investigation, a possible next step is statistical inference for such quantities as the traffic intensity or the mean stationary waiting time.
The asymptotic behaviour of large loss networks
Authors: Zachary Stan
Published: November 2023

We study the limit behaviour of controlled loss networks as capacity and offered traffic are allowed to increase in proportion, reviewing and extending recent work based on the functional law of large numbers of Hunt and Kurtz. We consider in detail single and two-resource networks. In this paper we study large loss networks in which the offered traffic is subject to acceptance controls. We review recent work of Hunt and Kurtz (1994), who established rigorous results for the asymptotic dynamics of such networks as capacity and offered traffic are allowed to increase in proportion, and we relate these results to asymptotic equilibrium behaviour. We further study the detailed behaviour of networks with at most two resources, extending results of Bean et al. (1994b, 1995), and giving some additional results.
Introducing GLIM4
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

Statistical modelling is an iterative process. We have a research question of interest, the experimental or observational context, the sampling scheme and the data. Based on these data and the other information, we develop an initial model, fit it to the data and examine the model output. We then plot the residuals, check the model assumptions and examine the parameter estimates. Based on this model output, we may modify the first model possibly through some transformation or the addition or subtraction of model terms. Fitting the second model may in turn lead to further models for the data, with the form of the current model being based on the information provided by the previous models. This interactivitybetween the data and the data modeller is a crucial feature of the process of statistical modelling. While automatic model selection procedures provided in many software packages can provide guidance in large problems, we take a different route in this book.
Binary response data
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

Much social science data consist of categoricalvariables. Familiar examples are religion, nationality, residence (urban/rural), type of dwelling, level of education and social class. The categories may be unordered (religion, nationality) or ordered (degree of disablement, attitude to a social question).
Multinomial and Poisson response data
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

The file faults gives the number n of faults in 32 rolls of material of length l metres; the data come from Bissell (1972), and are reproduced in Table 5.1. The number of faults is a non-negative integer, and is naturally modelled by the Poissondistribution, the standard model for count data.
Survival data
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

Over the last 30 years there has been a rapid development of probability models and statistical analysis for technological and medical survival data. Many studies have been made of the length of life or of periods of remission of animal or human subjects being treated for serious diseases. These studies have used probability models for duration of life which originated in engineering reliability studies of the operating lifetimes of electrical and mechanical systems. We will use the terms “death” and “failure” interchangeably to represent the events and “survival time” to represent the times to these events. In this chapter we give an account of the main probability models and their use in data analysis. The recognition of the special form of the likelihood in an important class of these distributions allows their simple fitting as generalized linear models. Many books are now available on survival analysis; a concise account can be found in Cox and Oakes (1984), detailed discussions in Kalbfleisch and Prentice (1980) and Lawless (1982), and more applied treatments in Collett (2003) and Hosmer and Lemeshow (1999).
Finite mixture models
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

The exponential family of distributions and its extensions discussed in earlier chapters are extremely useful in statistical analysis, but they cannot represent all types of data of scientific interest. In this chapter we consider a general extension of the exponential family to mixturesof distributions from this family. The need for this extension will become clear in subsequent chapters in which we discuss random effect models and their fitting by ML.
Random effect models
Authors: Aitkin Murray , Francis Brain , Hinde John
Published: November 2023

In Chapter 5 we found overdispersion in the fabric fault data; the Poisson GLM did not fit or represent the data adequately. The failure of a GLM to fit may be due to several causes. The distribution of Ymay not be the specified exponential family member, or the regression model fitted may be mis-specified. A fruitful way of expressing the problem, which unifies these two possibilities, is through omitted variablesfrom the regression model: the full model we have fitted is missing one or more important variables. If these have been recorded then they can be added to the model and fitted in the usual way (e.g. interactions). The common reality however, especially in survey or observational studies, is that we do not know what variables shouldhave been recorded or measured to construct an adequate model.
Radial Basis Function Networks and Statistics
Authors: Lowe David
Published: November 2023

The class of neural network architectures known as radial basis functions has a structure and history which has produced strong links with various areas in the statistical sciences. This chapter reviews some of the more salient aspects, which include the links with conditional and unconditional density estimation (such as Gaussian mixture models), regression problems and links with kernel estimators and linear smooths, supervised feature extraction and discriminant analysis, and topographic feature extraction and links to multidimensional scaling, Sammon mappings and nonlinear principal component analysis.
Robust Prediction in Many-parameter Models
Authors: Intrator Nathan
Published: November 2023

When parameter estimation is based on a set of training patterns with size that is of the order of the number of free parameters, estimation may become very unreliable. Until recently, estimation in such cases had sounded unrealistic, but it has now been accepted that such estimation is possible under certain conditions. For example, linear discriminant analysis (Fisher, 1936) requires some adjustment when the input dimensionality is large (Buckheit and Donoho, 1995) to account for the added variability of the covariance matrices. In simple terms, innovative ways to reduce the variance portion of the error are required, as well as methods to impose (reasonable) bias.
Density Networks
Authors: MacKay David J C , Gibbs Mark N
Published: November 2023

A density network is a neural network that maps from unobserved inputs to observable outputs. The inputs are treated as latent variables so that, for given network parameters, a nontrivial probability density is defined over the output variables. This probabilistic model can be trained by various Monte Carlo methods. The model can discover a description of the observed data in terms of an underlying latent variable space of lower dimensionality. We review results of the application of these models to toy problems with categorical and real-valued observables and to protein data.
Analysis of Latent Structure Models with Multidimensional Latent Variables
Authors: Dunmur A P , Titterington D M
Published: November 2023

Within the total interface between statistics and neural computing, we shall concentrate in this chapter on the particular area of latent structure models, which has attracted considerable recent interest in the neural-computation literature. We shall review this activity and attempt to relate it to the statistical literature. There are new slants, especially in the form of new models and new computational ideas. The plan of the chapter is as follows. In Section 1 we outline the general framework of latent structure models, following this in Section 2 with statements of the structures associated with latent trait, latent profile and latent class models, with particular emphasis on the case of multidimensional latent variables. Section 3 discusses maximum likelihood estimation of the parameters in the models, using the EM algorithm, and identifies a problem of computational complexity in the E-step. Section 4 describes how so-called mean-field approximations have been developed in response to this difficulty. Bayesian approaches are described in Section 5, implemented mainly using versions of the Gibbs sampler.
The secret of the intermittent fevers
Authors: Mazzarello Paolo
Published: November 2023

Golgi’s experimental work on intestinal parasites and the transmission of anthrax in the early 1880s was not a momentary fancy after many years of almost exclusive focus on the nervous system. Indeed, Golgi’s long-lasting interest in the study of infectious diseases had been overshadowed only by his passion for neurohistology. The electrifying discoveries made in microbiology at the beginning of the 1880s, however, would be instrumental in transforming what had been only a latent interest into the main focus of his research activity.
The prophets of the neuron
Authors: Mazzarello Paolo
Published: November 2023

By the mid-1880s the black reaction, although discovered more than ten years earlier, was still known to only a small number of researchers. Only a few years later, in the early 1890s, the most important neurobiologists were hailing it as a breakthrough. It was an irony of fate that a crucial role in this dramatic change was played by a young Spanish scientist who would later become Golgi’s most formidable scientific opponent.
Golgi versus Cajal: holism versus reductionism at the dawn of the neurosciences
Authors: Mazzarello Paolo
Published: November 2023

In 1891, while Golgi was making a last attempt to convince his critics of the reality of the diffuse neural net, Cajal and van Gehuchten developed a physiological model in which dendrites, cell body, and axon played well-defined roles in the mechanism of nervous transmission. In contrast to the static model propounded by His Sr and Forel, Cajal was in fact propounding a more dynamic vision of the nerve cell, and van Gehuchten moved in the same direction, albeit with some small differences. We have seen that Cajal began to hint at the idea of directional flow of nerve currents in 1889 while investigating the relationship between the basket cells and Purkinje cells. Two years later, this vague intuition became the ‘law of dynamic polarization’, according to which the dendrites (and the cell body as well) receive nerve impulses, which are then transmitted to the cylindraxis (the conduction apparatus), which in turn distributes them to the terminal varicose arborization (emission apparatus).
Siamese twins joined at the shoulder
Authors: Mazzarello Paolo
Published: November 2023

After these telegrams, Golgi sent more formal letters of thanks to both Holmgren and Morner. In the letter to Holmgren, he also expressed regret that the news was by now widely known, ‘though I’m not responsible for this. I believe that this occurred because [as soon as] the telegram was received by the Post Office it quickly made the rounds of a small town like Pavia, and from here to all of Italy.’
Back to research
Authors: Mazzarello Paolo
Published: November 2023

He used the prestige associated with the Nobel Prize to further his efforts for the renovation of the University and to ward off the Milanese foe. Meanwhile, in July 1905 the Parliament had approved a law that allowed the creation in Milan of Clinical Institutes for Specialist Studies, which it endowed with a modest State contribution. In December a non-profit organization was created to manage the Clinics of Obstetrics and Gynaecology, of Occupational Diseases, and of Infectious Diseases. The courses would be taught by instructors equivalent in status to university professors. The Clinic of Obstetrics and Gynaecology was inaugurated in 1906 while the Clinic for Occupational Diseases was in advanced stages of construction.
The veil of Isis
Authors: Mazzarello Paolo
Published: November 2023

Golgi’s cultural formation was permeated by positivism. For him, science was the supreme ideal, to which one could consecrate one’s entire life. Only science could guarantee continuous unending progress for humankind. From this perspective, metaphysical speculations had no relevance for an understanding of the human condition.
The representation of space in the primate hippocampus, and its role in memory
Authors: Rolls Edmund T
Published: November 2023

The aims of this chapter are to consider how space is represented in the primate hippocampus, how this is related to the memory functions performed by the hippocampus, and how the hippocampus performs these functions. In addition to the evidence that is available from anatomical connections, the effects of lesions to the system, and recordings of the activity of single neurones in the system, neuronal network models of hippocampal function will also be dis¬ cussed, as they have the promise of enabling one to understand what and how the hippocampus computes, and thus to understand the functions being performed by the hippocampus. The neurophysiological and brain lesion studies described have been performed (unless stated otherwise) with macaque monkeys in order to provide information as relevant as possible to understanding memory systems and amnesia in humans.
Hippocampal and parietal contribution to topokinetic and topographic memory
Authors: Berthoz Alain
Published: November 2023

The purpose of this paper is to address the question of a particular aspect of spatial memory: the memory of self-produced movement in a spatial environment. The mathematician H. Poincare wrote: ‘ To localise a point in space is to imagine the movement necessary to reach it’ (Poincare 1970, p. 67). By this statement he proposed a dynamic theory of spatial memory very different from the current theories, which suppose that, because there are ‘ place cells’ in the hippocampus, or because spatial coordinates seem to be represented in the parietal cortex, the brain codes space on static ‘ topographical maps’ (O’ Keefe & Nadel 1978; Anderson 1995). Indeed, most studies concerning spatial memory have considered visual representational memory in static object recognition and recall processes (Smith & Milner 1981; Mishkin et al. 1983). In addition, most studies of the neural basis of spatial memory have been based on types of mental exploration of the environment that adopt a ‘ survey’ type of strategy, although dissociations between route and topographical memory have been found (Incisa della Rocchetta et al. 1996). In the field of visual exploration, alternative hypotheses have been proposed (Droulez & Berthoz 1990, 1991; Colby et al. 1995), which promote the idea that the brain is using some dynamic processes to reprsent space and to control either executed or imagined movements.
Sensory gain control (amplification) as a mechanism of selective attention: electrophysiological and neuroimaging evidence
Authors: Hillyard Steven A , Vogel Edward K , Luck Steven J
Published: November 2023

Both physiological and behavioral studies have suggested that stimulus-driven neural activity in the sensory pathways can be modulated in amplitude during selective attention. Recordings of event-related brain potentials indicate that such sensory gain control or amplification processes play an important role in visual-spatial attention. Combined event-related brain potential and neuroimaging experiments provide strong evidence that attentional gain control operates at an early stage of visual processing in extrastriate cortical areas. These data support early selection theories of attention and provide a basis for distinguishing between separate mechanisms of attentional suppression (of unattended inputs) and attentional facilitation (of attended inputs).
Microglia in the Developing and Mature Central Nervous System
Authors: Perry V H
Published: November 2023

The term microglia is used to describe cells with a distinct morphology and phenotype that lie within the parenchyma of the central nervous system (CNS) (Figure 4.1). These cells, described and named by de! Rio Hortega (1932), are the resident macrophages of the CNS parenchyma. Although there has been considerable debate as to whether these cells were derived from monocytes or not, there is now overwhelming evidence to support the idea that they are of monocytic origin (for references, see Ling, 1981; Ling and Wong, 1993). There is no convincing evidence for a population of cells within the CNS, of neuroectodermal or other non-monocytic origin, with the morphology and phenotype of those illustrated in Figure 4.1.
Concepts in Myelin Sheath Evolution
Authors: Colman D R , Pedraza L , Yoshida M
Published: November 2023

What were the evolutionary pressures that led to the recent (in evolutionary terms) invention of the morphologically complex, biochemically unique and functionally essential vertebrate myelin sheath? It is frustrating that a definitive answer to this question may remain elusive. There is a single major reason for this unsatisfying situation. The specialized proteins and membrane domains which form the myelin sheath must have evolved gradually, and the myelin protein genes themselves heterochronically in the first jawed vertebrates. Semi-myelinated vertebrate organisms must have once existed, but none exist in our time; the myelin sheath is either fully developed in both the central nervous system (CNS) and peripheral nervous system (PNS) as it is in the vast majority of vertebrates, or it is absent as in the jawless fish (Bullock et al., 1984). We can only guess then, about the original features of the first myelin-like ensheathment, that we believe appeared only about 440 million years ago. As molecular biological investigations are expanded to include extensive phylogenetic analyses of myelin-related genes, and these data are compared with significant landmarks in vertebrate evolution gleaned from the paleontological record, we may arrive at probable and perhaps compelling arguments about myelin sheath origins. There have been several interesting viewpoints on how we might reconcile in general terms the fossil record with molecular studies, and why the two lines of investigation are interdependent (see, for example, Graur, 1993; Eeernisse and Kluge, 1993; Honeycutt and Adkins, 1993; Patterson et al., 1993; Maizels and Ashburner, 1994; Morris, 1994a,b; Meyer, 1995).
Axon-Schwann Cell Interactions during Peripheral Nerve Degeneration and Regeneration
Authors: Scherer S S , Salzer J L
Published: November 2023

Wallerian degeneration refers to all of the events that occur distal to the site of axotomy (for recent reviews, see Ide, 1996; Fu and Gordon, 1997; Stoll and Muller, 1999; Terenghi, 1999). Although usually induced by mechanical injury in experimental studies, Wallerian degeneration is a feature of any insult that causes axonal degeneration. During the first week post-axotomy, axons fragment and disappear, and the myelin sheaths separate at incisures, breaking up into so-called ovoids. Over the next few weeks, these myelin ovoids are phagocytosed in part by Schwann cells but mainly by macrophages that invade the degenerating nerve. The clearance of myelin debris by macrophages promotes axonal regeneration (Dahlin, 1995), perhaps owing to the ability of myelin proteins to inhibit axonal regeneration (see Chapter 14). Schwann cells undergo extensive proliferation between 3 and 5 days post-axotomy (Oaklander and Spencer, 1988). The basal lamina persists and surrounds the column of ‘denervated’ Schwann cells, traditionally called a band of Büngner..
Analysis of variance methods
Authors: Diggle Peter J , Heagerty Patrick J , Liang Kung-yee. , Zeger Scott L
Published: November 2023

In this chapter we describe how simple methods for the analysis of data from designed experiments, in particular the analysis of variance (ANOVA) can be adapted to longitudinal studies. ANOVA has limitations which prevent its recommendation as a general approach for longitudinal data. The first is that it fails to exploit the potential gains in efficiency from modelling the covariance among repeated observations. A second is that, to a greater or lesser extent, ANOVA is a simple method only with a complete, balanced array of data. This second limitation has been substantially diminished by the development of general methodolodgy for incomplete data problems (Little and Rubin, 1987), but the first is fundamental. Whether it is crucial in practice depends on the details of the particular application, for example the size and shape of the data array. As noted in Section 4.1, modelling the covariance structure is most valuable for data consisting of a small number of long sequences of measurements.