Showing papers by "Keele University published in 1981"

Animal models of tinnitus

Abstract: There are few physiological data available on the origin and nature of tinnitus. It is not even known whether tinnitus associated with cochlear pathology is a manifestation of increased or decreased activity in the cochlear nerve. In previous investigations of cochlear pathology, the spontaneous neural activity has generally been found to be depressed. In the present experiments, an animal model has been established by the administration of sodium salicylate in doses producing blood concentrations that evoke tinnitus in humans. Under these conditions, changes occur in cochlear nerve-fibre thresholds and tuning, similar to those obtained in other types of cochlear pathology. However, under salicylate, the distribution of spontaneous discharge shifts significantly to higher rates than normal. These changes are accompanied in some, but not all, fibres by changes in the temporal patterns of discharge suggestive of excitation. In the second animal model studied, a normal guinea-pig that had a naturally occurring continuous tonal emission, analogous to that recently recorded in human "physiological" tinnitus, was investigated in detail. The emitted signal was recorded in the ear-canal acoustic pressure and in the round-window potential. Several lines of evidence point to the signal as being cochlear in origin, including: its resistance to muscular paralysis and section of the stapedius muscle; the effects of changes in middle-ear pressure; its reversible elimination by hypoxia; and its suppression by tones of higher frequency.

Organization and nucleotide sequence of a new ribosomal operon in Escherichia coli containing the genes for ribosomal protein S2 and elongation factor Ts

Abstract: We report the nucleotide sequence of the four min region of the Escherichia coli genetic map that includes the genes for ribosomal protein S2 (rpsB) and translation elongation factor EF-Ts (tsf), and the possible location of regulatory sites within this two gene operon. The data indicate that the gene order is: rpsBp-rpsB-tsf-tsft. One potential regulatory site is a 16 nucleotide sequence in the rpsB leader region encompassing the ribosome binding site and the translation initiation codon. This has a high degree of homology with nucleotides 8 through 23 on the 5' end of 165 ribosomal RNA, and might signify a sequence that is necessary for post-transcriptional control of rpsB expression. The data allow one to infer the amino acid sequences of S2 and EF-Ts.

Eighty ways of improving instructional text

Abstract: This paper presents suggestions for improving instructional text under three main headings: prose materials, graphic materials, and typographic considerations. Each suggestion is based on research findings and references are made to this research whenever possible. Readers are reminded, however, that these suggestions are generalizations — often drawn from specific and limited cases — and caution is therefore necessary in their application.

Acoustic correlates of tonal tinnitus.

Abstract: A sensitive microphone has been developed which can pick up tonal signals (spontaneous acoustic emissions) in the sealed ear-canal of certain subjects. Various properties of these frequency components suggest that they arise from an active, frequency-selective self-limiting feedback process within the cochlea and that they rely on internal reflection from the middle ear. An external tone can synchronize, frequency-lock, suppress of frequency-shift the acoustic component. These interactions are frequency-dependent in a way suggestive of cochlear tuning properties. Positive or negative middle-ear pressure can also influence the components by increasing their frequency and in some cases can enhance one component at the expense of a neighbouring one. Some subjects hear these components as tinnitus and can report on the measured changes. Other subjects do not hear the measured signals, which otherwise behave similarly. A third group of subjects have tinnitus but no objective sound can be detected. In this last group there are, nevertheless, sometimes notches or other discontinuities in the audiogram which correspond to their tinnitus pitch-matches. It appears likely that the recordable type of tinnitus is essentially non-pathological and represents hypersensitivity of the system, whereas the non-recordable type might be associated with local pathological changes at the end-organ or more centrally.

Modulatory influences of moving textured backgrounds on responsiveness of simple cells in feline striate cortex.

Abstract: 1. The modulatory influences of synchronously moving textured backgrounds on responsiveness to optimally oriented moving bar stimuli were investigated in 107 simple cells, with incidental observations on four complex cells, recorded in the lightly anaesthetized feline striate cortex. 2. Background motion depressed bar responsiveness in 74% of simple cells, facilitated bar responsiveness in 4%, and was without influence in 22%. These results confirm our earlier observations (Hammond & MacKay, 1977). 3. Moving chequerboard patterns typically elicited stronger effects than moving visual noise. 4. Occluding a moving background by a mask of stationary texture of variable width and length indicated that the zone of background influence extended well beyond the excitatory receptive field along its axis, but not transverse to it. This was confirmed by a converse experiment using a window of moving texture in an otherwise stationary background. 5. The influence of background motion varied markedly with location relative to the cell's receptive field. A small stationary rectangular window of moving texture at different locations along the receptive field axis typically suppressed bar response when over the receptive field, but facilitated it at either end. Conversely, with the background moving and the masking texture stationary, suppression was minimal when the masking patch was centred over the receptive field. 6. Systematically varying the phase relationship between bar and background motion showed the interaction in simple cells to be greatest for in-phase motion and least for motion in antiphase. The opposite is true for complex cells. 7. All the above effects showed non-linearities and could be enhanced by making texture velocity greater than bar velocity or by selecting the polarity of contrast and length of a bar stimulus of optimal orientation and width so as to elicit relatively weak (submaximal) criterion responses. 8. Since textured backgrounds themselves evoke no response from simple cells, and since all specific afferents are known to be excitatory, it seems likely that textural influences upon simple cells are mediated only through complex cells.

Stream Phosphorus Exports from Watersheds with Contrasting Land Uses in Southern Ontario

Abstract: The export of dissolved molybdate reactive phosphorus (DMRP) from 22 watersheds in the Duffin Creek drainage basin near Toronto Ontario was measured over a 25-month period. The annual average loss varied from 0.027 to 2.11 kg P/ha. Phosphorus levels in a number of watersheds were strongly influenced by effluent from a sewage treatment plant which contributed about 68 percent of the annual DMRP input to Duffin Creek. An analysis of 12 watersheds which did not contain major point pollution sources revealed that DMRP concentration and losses had a significant positive correlation with crop area and a strong negative association with forest, abandoned farm land, and area of sand + sandy loam soils. The causal relationships underlying these simple correlations are difficult to evaluate because of considerable multicollinearity between land use, soil, and topographic variables. Analysis of a mass balance for the downstream reaches of Duffin Creek indicated that there was considerable retention of phosphorus in the river channel particularly during summer low flows.

Differential responsiveness of cells in the visual zones of the cat's LP-pulvinar complex to visual stimuli

Abstract: Multiple visual field representations are contained within the feline LP-pulvinar complex; regions differentiated by their afferent and efferent connectivity patterns as the striate-, tecto- and retino-recipient zones. Cell responses from these visuotopic zones were investigated in immobilized cats under N2O/O2 supplemented with pentobarbitone or Althesin, using spot, bar and textured stimuli.

The Dynamic Range Problem: Place and Time Coding at the Level of Cochlear Nerve and Nucleus

Abstract: The greatest obstacle to a straightforward acceptance of the ‘place’ theory of the coding of frequency in the auditory system is the ‘dynamic range problem’ (Evans, 1977ab, 1978ab, 1980a). It is an everyday experience that our ears can operate over an amazingly large dynamic range approaching 100dB, yet the dynamic range of the great majority of cochlear nerve fibres is remarkably limited. The solution to this problem has implications both for our understanding of the fundamental mechanisms of the neural coding of auditory stimuli (Evans, 1978a) and for the design of multi-channel electrical prostheses intended to impart speech information to the profoundly hearing impaired (Evans, 1978b). This paper briefly reviews the problem and discusses various possible solutions in the light of recent physiological data.

On Moral Properties

Abstract: and I shall allow myself to talk of one property resulting from a set of other properties. So we have it that if an action has a moral property M, its M-ness results from some of its non-moral properties. These non-moral properties may be called the reasons why it is M, and typically they will form a rather small group among the action's non-moral properties. But when a man decides that the action is M, his reasons will probably form an even smaller group; in a favourable case, fas reasons will be among the reasons why it is M, but in an unfavourable case, they will not. In morals as elsewhere, a man can reach the right conclusion for the wrong reasons, and even where he reaches the right conclusion for sound reasons, he need not have exhausted all the available reasons. All this might seem, from a certain point of view, uncontentious enough. Sir David Ross expresses it this way:

Plasma corticosterone fluctuations during the oestrous cycle of the house mouse.

Abstract: The circadian rhythm of corticosterone concentration in the mouse persists throughout the oestrous cycle, but concentrations are significantly elevated at proestrus and oestrus.

Toward A Taxonomy and Conceptual Model of Play

Abstract: The study of play has a longer history than the study of psychology itself, but the ideas about the phenomenon have shown remarkable changes according to the prevailing climate and conditions

Out of Place: Female Offenders in Court:

Abstract: The author considers the treatment received in court by female offenders and concludes that women are more likely than men to be processed according to their ability to fulfil a certain traditional role in their lives outside the court than according to their offence. Women are seen to be 'out of place' in the criminal justice system and it is argued that this is not necessarily to their advantage.

Distribution and feeding of larval Chironomidae in a gravel‐pit lake

Abstract: SUMMARY. Replicated benthic samples were collected from a wet gravel-pit in the English Midlands at fortnightly intervals during 1978. The aggregation patterns of the four most numerous genera, Chironomus, Polypedilum, Procladius and Tanypus, were analysed by fitting the means and variances of replicated sampling units to Taylor's power law and Iwao's plot of mean crowding against mean density. Chironomus larvae were not aggregated; all other genera showed an increased aggregation with density. The Iwao plots indicated that Tanypus larvae tended to be aggregated at low as well as high densities. Gut contents were analysed in larvae of the above genera and also in Cryptochironomus larvae, to investigate the relationship between dispersion pattern and feeding. Chironomus and Polypedilum larvae fed mainly on detritus, Tanypus on algae, Procladius on algae and crustacea and Cryptochironomus on oligochaetes. The extent of overlap in feeding niche was measured by Levins’ index and shown to be low in all except the pair feeding upon detritus. Differences in the feeding niche may partly account for the dispersion patterns of the genera investigated.

John Hopton: A Fifteenth Century Suffolk Gentleman

Abstract: Preface A note on sources Abbreviations Maps Introduction 1. How John Hopton obtained his livelihood 2. The estates 3. John Hopton and his family 4. Acquaintances, neighbours and friends Conclusion Index.

Attending To Two Melodies At Once: the of Key Relatedness:

Abstract: How do we listen to contrapuntal music? This question is of considerable psychological interest because an appreciation of counterpoint would seem to require the ability to attend to at least two concurrent independent melodic streams. Common sense and psychological evidence, however, tell us that our ability to do two things at once is severely limited. An extreme view of the situation (e.g. Broadbent, 1958) is that our attention is limited to a single channel at any one time. In musical terms this would mean that the best any listener could do would be to rapidly switch attention between the different parts or instruments. A less extreme view (e.g. Allport, 1980) is that two things may be attended to at once provided that they do not use the same processing mechanisms. Thus, although it is impossible to listen to two conversations simultaneously, it is possible to listen to a conversation at the same time as attending to the road condition whilst driving a car. Although the evidence for this latter view is now considerable, its application to music is doubtful. Whatever processing mechanisms are employed to deal with melodies are surely going to be called upon for each of the simultaneous lines in a contrapuntal piece. Thus, listening to this type of music is analogous to listening to two conversations at once.

Allopathic medicine, profession, and capitalist ideology in India.

Abstract: It is argued that, notwithstanding medical pluralism, allopathic medical ideology in India is of importance beyond health and medicine in the legitimation and reinforcement of capitalist state power. It is seen as the bearer of an urban, male, technological, hospital-based, cosmopolitan, curative, and individualistic world view. Three cases are presented—the use of medical terms in industry, the events surrounding the President's 1977 illness, and a so-called “epidemic” of poisoning amongst bonded Nagesia tribals in Madhya Pradesh. Finally, it is suggested that other forms of medical ideology have weaker social bases and can provide no institutional challenge even to an admittedly poorly organized allopathic profession.

Colour patterns of Syrphidae. III. Sexual dimorphism in Eristalis arbustorum

Abstract: . 1. The hoverfly Eristalis arbustorum L. (Diptera, Syrphidae) is a sexually dimorphic Batesian mimic of bees and wasps. 2. This dual mimicry entails good mimicry of several small, dark bees (mainly mining bees) by female E.arbustorum, and less specific mimicry of wasps and other yellow and black Hymenoptera by males. 3. There is also variability of colour pattern within both sexes of E.arbustorum. 4. Seasonal fluctuations in the pattern frequencies of males occur because the temperature during pupal development influences the coloration of the adult. 5. Temporal changes in the pattern frequencies of females are attributable to developmental darkening of the abdomen. 6. These effects can be explained by the fact that the phenotypic requirements for thermoregulation and protection against predation will be different for males and females, and will also vary with time. 7. Behavioural differences between males and females are a component of the sexual dimorphism in this species.