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ObjectivesCases of sporadic vestibular schwannoma (sVS) have a low rate of association with germline pathogenic variants. However, some individuals with sVS can represent undetected cases of neurofibromatosis type 2 (NF2) or schwannomatosis. Earlier identification of patients with these syndromes can facilitate more accurate familial risk prediction and prognosis.MethodsCases of sVS were ascertained from a local register at the Manchester Centre for Genomic Medicine. Genetic analysis was conducted in NF2 on blood samples for all patients, and tumour DNA samples when available. LZTR1 and SMARCB1 screening was also performed in patient subgroups.ResultsAge at genetic testing for vestibular schwannoma (VS) presentation was younger in comparison with previous literature, a bias resulting from updated genetic testing recommendations. Mosaic or constitutional germline NF2 variants were confirmed in 2% of patients. Pathogenic germline variants in LZTR1 were found in 3% of all tested patients, with a higher rate of 5% in patients SMARCB1 variants were identified within the cohort. Considering all individuals who received tumour DNA analysis, 69% of patients were found to possess two somatic pathogenic NF2 variants, including those with germline LZTR1 pathogenic variants.ConclusionsUndiagnosed schwannoma predisposition may account for a significant minority of apparently sVS cases, especially at lower presentation ages. Loss of NF2 function is a common event in VS tumours and may represent a targetable common pathway in VS tumourigenesis. These data also support the multi-hit mechanism of LZTR1-associated VS tumourigenesis.

Metrology applications commonly require non-contact, capacitive sensors for displacement measurements due to their nanometer resolution. In some metrology applications, for example, the measurement of roundness and spindle error motion, the displacements of stationary and rotating cylindrical artifacts are measured. Error from using a conventionally calibrated sensor with a non-flat (e.g., cylindrical) target is typically neglected, but these errors cannot be ignored for nanometer-level accuracy. The capacitance between a sensor and a cylindrical target is less than that of a sensor with a flat target, which causes four effects. As the diameter of the target shrinks, the sensitivity of the sensor increases, the sensing range decreases, the sensing range shifts towards the target, and the nonlinearity increases. These errors can be greatly reduced by either calibrating sensors with the correct target surface or by determining corrections for post-processing data. This paper quantifies and experimentally verifies these errors for a commonly used sensor, and a simulation of a nanometer-level measurement of out-of-roundness and spindle error motion demonstrates that measurement accuracy is improved with corrected sensitivities.

Capacitive displacement sensors are widely used in precision manufacturing and metrology because they measure displacements with nanometer resolution. Prior literature usually treats capacitive sensors consisting of electrodes arranged as parallel plates. In this work, the target electrode is spherical, which is common in machine tool metrology, spindle metrology, and the measurement of sphericity. The capacitance due to a gap between flat and spherical electrodes is less than that of two flat electrodes, which causes four effects. As the diameter of the target electrode is reduced, the sensitivity increases, the sensing range decreases, the sensing range shifts toward the target, and the sensor becomes nonlinear. This paper demonstrates and quantifies these effects for a representative capacitive sensor, using finite element analysis and experimental testing. For larger spheres, the effects are correctible with apparent sensitivities, but measurements with the smallest spheres become increasingly nonlinear and inaccurate.

Structural equation modelling (SEM) is outlined and compared with two non-linear alternatives, artificial neural networks and “fast and frugal” models. One particular non-linear decision-making situation is discussed, that exemplified by a lexicographic semi-order. We illustrate the use of SEM on a dataset derived from 539 volunteers' responses to questions about food-related risks. Our conclusion is that SEM is a useful member of the armoury of techniques available to the student of human judgement: it subsumes several multivariate statistical techniques and permits their flexible combination, and it provides robust goodness-of-fit statistics and is available in (generally) easy-to-use computer packages. Although the number of tasks for which SEM provides a persuasive psychological model is small, it is very useful in identifying the important variables and their inter-relations that contribute to task performance, and thus can constitute a valuable intermediate staging point between raw data and a fully...

The principal novel feature of this paper is the notion that a coherent memory can be synthesised from a set of partially coherent memory fragments by maximising a particular function, Harmony (Smolensky, 1986). The appeal of Harmony is that it fulfils two functions: it is at the heart of the synthesis algorithm and it provides a natural measure for "feeling-of-knowing". The model is applied to feeling-of-knowing data, flashbulb memories, flashbacks, repression, dissociation, memory stability across repeated recalls, and the effects of cue size on retrieval.

The study reported here considers the deterrent effect of terrorist incidents on the rates of luggage theft in railway and underground stations. We selected for our task a well-publicized major terrorist incident that took place on 18 February 1991. The analysis of the data shows that in the periods immediately following the terrorist incident there was a sharp but short-lasting decline in the number of cases of luggage theft. This indicates that either increased police vigilance, or the fear of potential thieves that items of luggage might contain explosives, produces a definite if short dived deterrent effect. One of the most debated and controversial issues in modern criminal justice policy is that of general deterrence, i.e. the inhibiting effects of sanctions on the illegal activity of potential criminals. (Zimring and Hawkins 1973; Beyleveld 1979, 1980; Tittle 1980; Walker 1991). The underlying assumption of general deterrence theory and associated policy is that individuals calculate the risk involved in criminal activity and refrain from it, because of their fear of punishment. Used in this sense, deterrence assumes a rational calculation of benefits and risks, including the probability of detection as well as the severity and swiftness of punishment by the potential offender. Indeed, utilitarian writers and economic and modern classical theorists argue that the purpose of criminal justice is to create an organized system of official threats sufficient to outweigh the perceived benefits of committing a crime (Bentham 1789; Posner 1985; Walker 1991). Opponents of the validity of the concept of general deterrence, on the other hand, dispute the thesis that potential criminals calculate risks in a rational manner and reject the view that the perception of the danger that they will be apprehended and punished for their misbehaviour has any significant deterrent effect. They argue that people tend to commit offences almost irrespective of the risk involved.1 The identification and measurement of deterrence are notoriously difficult for researchers, because of the methodological and ethical problems involved. As Ash worth points out, satisfactory empirical evidence is difficult to obtain since 'the condi tions must be such that non-offending can safely be ascribed to the deterrent effect of the sanction rather than other factors' (Ashworth 1994).

Rules for writing certain phonemes (/s/, /z/, /r/, /t/ and /d/) in Pitman New Era shorthand are systematically examined and their frequency of usage estimated. In particular, we identify three types of rule (default rules, other rules and short forms) and suggest correspondences between them and the classification of words in standard English orthography as regular, exception and strange. Twelve experienced shorthand writers wrote to dictation, in shorthand, passages of prose and lists of nonsense words. With real words there were effects of word frequency on percent correct. These were strongest for short forms and weakest for default rules. Nonsense words were less accurately transcribed than real words, and this effect was particularly marked for vocalic /r/. We conclude that lexical effects are just as strong for shorthand (which is taught by explicit rules) as it is for English orthography (where the rules are less systematic). In particular, there is no support for the notion that shorthand...

This paper has two goals: to demonstrate the importance of the feature representation chosen for a connectionist model, and to examine the properties of a particular model, the back-propagation algorithm, in conditions intended to simulate the ‘graceful degradation’ encountered in human ageing. In a concept learning simulation, the number of zero or near-zero values of the input features and in the responses of the hidden units was found to influence speed of learning, strength of response to a prototype, and performance with distorted input (the latter two being inversely related). Degradation of the network prior to learning enhanced prototype performance but disrupted distortion performance. In the light of these results we discuss the design of efficient learning algorithms and the potentiality of these networks as models for human ageing.

Models for letter cancellation are developed, i.e. for tasks where subjects read a coherent piece of prose at the same time as trying to cancel every target letter they encounter. These models have two components (i) a model of how information is represented by the reader, (ii) a model of how this information is scanned to enable the reader to detect particular target letters. Models of representation range from a photographic image of the printed page to a sophisticated multi-level representation, and models of scanning range from a series of independent saccadic movements (like eye movements) to scans which take into account morphemic and syntactic structure. Several predictions about the detailed pattern of letter cancellation data are developed on the basis of these models, and these are tested on a data base collected by Smith and Groat (1979). While some support for the simpler models is forthcoming, only the most elaborate models (multi-level representation, syntactically guided scan) can fully account for all the data. While instances can be found where the cancellation task is clearly disrupting the reading task, much of the data are consistent with the notion that the letter cancellation task is not excessively intrusive, and our analyses can thus give us significant information about normal reading.

It is argued that current scaling models when they are applied to perceptual and mnemonic processes are out of touch with psychological theory. As an alternative, a psychological model is proposed in which stimuli are analysed by a series of feature tests, each feature test being dependent on the results of earlier feature tests in the series and on the other features present in the stimulus. Computer programs are described which fit such models to data, the output of such programs being the best-fitting hierarchy of feature tests. Detailed analyses are produced for data drawn from studies of speech perception and memory for speech; differences between normal, deaf and aphasic subjects are also discussed. It is claimed that, in comparison with normal scaling methods or with descriptions based simply on raw confusions, this approach offers a more insightful analysis of such data.

Four models of the organization of feature-testing units in the perception of phonemes are developed and tested against data drawn from a number of published studies. The independence model, which asserts that features are tested independently of each other, is conclusively rejected. The response-conditional and stimulus-conditional models require individual feature-testing units to be dependent, respectively, on the responses of other feature-testing units and on the other features present in the stimulus. Both these models handle perceptual confusions very well among stop and nasal consonants, but are less satisfactory for fricatives. Finally, the correct-conditional model requires individual feature-testing units to be dependent on the correctness of the decisions made by other feature-testing units; this model is very poor for perceptual confusions but quite good for mnemonic confusions. In addition, some of the distinctive features currently favoured by linguists are shown to provide unsatisfactory descriptions. The implications of this study are that perceptual and mnemonic processes are different in certain basic respects, and that many current scaling models are ignoring important types of structure in the data they analyse.

This paper brings together two different psychological traditions in an attempt to understand children’s writing and spelling. The first tradition is information processing: the child is conceived of as a modular system through which information flows, and a theoretical menagerie of short-term stores, articulatory loops, logogens, visual analyzers, etc. provides an account of the production and perception of written material. Morton (1981) and Baddeley and Hitch (1974) exemplify this approach. The second tradition is structural analysis: the pattern of errors in the child’s output is used to infer the types of coding and levels of linguistic knowledge to which children have access in constructing written material. Cromer (1980), Nelson (1980) and Sterling (in press) typify this approach.