Showing papers by "University of St Andrews published in 1988"

Tactical deception in primates.

Abstract: Tactical deception occurs when an individual is able to use an “honest” act from his normal repertoire in a different context to mislead familiar individuals. Although primates have a reputation for social skill, most primate groups are so intimate that any deception is likely to be subtle and infrequent. Published records are sparse and often anecdotal. We have solicited new records from many primatologists and searched for repeating patterns. This has revealed several different forms of deceptive tactic, which we classify in terms of the function they perform. For each class, we sketch the features of another individual's state of mind that an individual acting with deceptive intent must be able to represent, thus acting as a “natural psychologist.” Our analysis will sharpen attention to apparent taxonomic differences. Before these findings can be generalized, however, behavioral scientists must agree on some fundamental methodological and theoretical questions in the study of the evolution of social cognition.

Origin of infracrustal (I-type) granite magmas

Abstract: I-type granites are produced by partial melting of older igneous rocks that are metaluminous and hence have not undergone any significant amount of chemical weathering. In the Lachlan Fold Belt of southeastern Australia and the Caledonian Fold Belt of Britain and Ireland there was a major magmatic event close to 400 Ma ago involving a massive introduction of heat into the crust. In both areas, that Caledonian-age event produced large volumes of I-type granite and related volcanic rocks. Granites of these two areas are not identical in character but they do show many similarities and are markedly different from many of the granites found in Mesozoic and younger fold belts. These younger, dominantly tonalitic, granites have compositions similar to those of the more felsic volcanic rocks forming at the present time above subduction zones. The Palaeozoic granites show little evidence of such a direct relationship to subduction. Within both the Caledonian and Lachlan belts there are some granites with a composition close to the younger tonalites. A particularly interesting case is that of the Tuross Head Tonalite of the Lachlan Fold Belt, which can be shown to have formed from slightly older source rocks by a process that we refer to as remagmatisation which has caused no significant change in composition. Since remagmatisation has reproduced the former source composition in the younger rocks, the wrong inference would result from the use of that composition to deduce the tectonic conditions at the time of formation of the tonalite. Granites, particularly the more mafic ones, will generally have compositions reflecting the compositions of their source rocks, and attempts to use granite compositions to reconstruct the tectonic environment at the time of formation of the granite may be looking instead at an older event. This is probably also the case for some andesites formed at continental margins.Several arguments can be presented in favour of a general model for the production of I-type granite sources by underplating the crust, so that the source rocks are infracrustal. Such sources may contain a component of subducted sediments with the consequence that some of the compositional characteristics of sedimentary rocks may be present in I-type source rocks and in the granites derived from them. The small bodies of mafic granite and gabbro associated with island arc volcanism have an origin that can be related to the partial melting of subducted oceanic crust or of mantle material overlying such slabs and can be referred to as M-type. These rocks have compositions indistinguishable from those of the related volcanic rocks, except for a small component of cumulative material. The tonalitic I-type granites characteristic of the Cordillera are probably derived from such M-type rocks of basaltic to andesitic composition, which had been underplated beneath the crust. Some of the more mafic tonalites of the Caledonian-age fold belts may also have had a similar origin. More commonly, however, the plutonic rocks of the older belts are granodioritic and these probably represent the products of partial melting of older tonalitic I-type source rocks in the deep crust, these having compositions and origins analogous to the tonalites of the Cordillera. In this way, multiple episodes of partial melting, accompanied by fractionation of the magmas, can produce quite felsic rocks from original source rocks in the mantle or mantle wedge. These are essential processes in the evolution of the crust, since the first stages in this process produce new crust and the later magmatic events redistribute this material vertically without the addition of significant amounts of new crust.

Song Learning in Zebra Finches (Taeniopygia guttata): Progress and Prospects

Abstract: Publisher Summary This chapter discusses on the recent findings in song learning in zebra finches and brings them together with earlier studies of song learning in this species, as well as recent physiological work on this species that is relevant to song development. Zebra finch song also affords excellent prospects for further advances in our understanding of principles of behavioral development; the review concludes by considering some of these remaining questions. The chapter summarizes briefly on what is known of the way of life of the zebra finch in the wild, where it occurs in Australia and the Lesser Sunda islands. It is an intensely sociable species, occurring in large flocks and breeding colonially in response to the rainfall, which is essential if there is to be sufficient food for feeding chicks. Zebra finch song seems largely to act as a signal between the sexes, although it is simple in structure and does not therefore fit easily into the scheme of song function. Rather than being concerned primarily with mate attraction or rival repulsion, its major role may be in stimulating ovarian development, including ovulation, a function song is known to possess in other species. This chapter describes what is known about the song-learning system in zebra finches and suggest ways in which the timing, accuracy, and selectivity of learning is affected by the environment that the young bird experiences during its development.

The Effects of Task on the Modulation of Event‐Related Potentials by Word Repetition

Abstract: Event-related potentials were recorded while subjects viewed 3 series of visually presented words. In each series some of the words were repetitions of an immediately preceding word. The subjects' task was to respond to occasional items (‘targets’), the nature of which was varied across the 3 series. Targets were either lower-case words, non-words, or animal names. When the targets were non-words or animal names, event-related potentials to repeated items were characterised by a large, Cz-maximum, positive-going shift with an onset latency of around 300 ms. When the targets were lower-case items, this repetition effect was greatly attenuated, due primarily to an increase in positivity in ERPs to unrepeated items. It is concluded firstly that the modulation of event-related potentials by word repetition is task-dependent. Secondly, the repetition effect seems better interpreted as an attenuation of an endogenous negativity present in ERPs to unrepeated items, than as a positive-going component elicited by repeats.

The evolutionary state of contact and near-contact binary stars

Abstract: Calcul des masses, rayons et luminosites des composantes de 31 systemes binaires de type F-K proches ou en contact

Nitrosyl Complexes of Iron-Sulfur Clusters

Abstract: Publisher Summary This chapter discusses nitrosyl complexes of iron-sulfur clusters. The recent upsurge of interest in iron-sulfur-nitrosyl complexes has been stimulated in part by the reported isolation of [ Fe2(SMe)2(NO)4] from natural sources, by the obvious resemblances between these complexes and the naturally occurring [2Fe–2S] and [4Fe–4S] clusters of iron-sulfur proteins, and by the connections between tetrairon-sulfur-nitrosyls and cubane-type clusters. Salts containing the anions [ Fe2S2(NO)4]2– and [Fe4S3(NO)7]– are often called, from their colors, Roussin's red and black salts, respectively. Similarly, the organic derivatives [Fe2(SR)2(NO)4] are often called esters of Roussin's red salt. The number of iron-selenium-nitrosyl complexes is substantially smaller than the iron-sulfur-nitrosyl species, and there are a number of differences between the sulfur systems and their analogs containing selenium or tellurium. For selenium it is convenient to divide the complexes into three classes, dependent upon the stoichiometry of the metal-chalcogen framework. A variety of routes have been employed for the synthesis of heterometallic clusters containing Fe(NO)S fragments, and examples of such systems have been described. The diamagnetic behavior of the diiron and tetrairon complexes, despite the presence of formally d7 and/or d9 iron centers, indicates very strong coupling between the individual paramagnetic centers.

Use of restriction endonucleases to study relationships between DNA double-strand breaks, chromosomal aberrations and other end-points in mammalian cells.

Abstract: Some of the cellular effects of radiation, such as mutations, chromosomal aberrations and cell killing, can be mimicked by inducing 'pure' double-strand breaks (dsb) in DNA of cells with restriction endonucleases (RE), although the chemical structure of the ends of dsb induced by RE are likely to differ from those induced by X-rays. Chromosomal aberrations are induced by treatment of cells with a variety of RE at all stages of the cell cycle. The frequency with which RE induce dsb in the DNA may be one factor determining the number of aberrations induced. However, the structure of the dsb generated may also determine the frequencies of aberrations induced. RE which generate 'cohesive-ended' dsb in the DNA have been shown to induce lower frequencies of aberrations than those causing 'blunt-ended' dsb, when inactivated Sendai virus is used to permeabilize cells. Other methods, involving a hypertonic shock to the treated cells, have led to results in which there is little or no difference in the effectiveness between the two types of dsb. It is argued here that the use of treatments which cause a hypertonic shock may influence the frequencies of aberrations induced.

The use of phonological information by good and poor readers in memory and reading tasks.

Abstract: There has been a recent debate about the utilization of phonological information by poor readers in both working memory and reading tasks. The purpose of the first experiment in this study was to examine whether the absence of phonological similarity effects in working memory reported in previous studies was due to inappropriate levels of task difficulty. Poor readers and their reading age controls were found to show a normal effect when the memory task was at an appropriate level of difficulty, but no effect when a large number of items had to be recalled. However, in a recognition memory task, the poor readers chose orthographically similar pairs, whereas the reading-age and chronological age controls chose phonologically similar pairs. The purpose of a final experiment was to determine whether or not the good and poor readers could be differentiated in terms of their reading strategies; both groups showed regularity effects in a naming task and pseudohomophone effects in a lexical decision task. However, although poor readers could read three-letter nonwords as well as their controls, they were significantly impaired in reading more complex one-syllable nonwords. It was concluded that poor readers may have a phonological dysfunction in some aspects of reading that is unrelated to whether or not they show phonological similarity effects in working memory. Impaired segmentation skills may underly their difficulties in both reading and nonreading tasks.

Thixotropic changes in human muscle stiffness and the effects of fatigue.

Abstract: Two methods have been used to study the stiffness of the relaxed finger musculature after movement followed by various times at rest. The muscles stiffen considerably as the time at rest increases. The time course of this change has been plotted; it continues at a declining rate for at least 30 min. The increased stiffness after resting can be immediately reduced by active or passive movements but not by isometric efforts. These changes characterize a thixotropic system and suggest a long-term molecular rearrangement in relaxed muscle. Extensive eccentric exercise of the muscles under investigation reduces the overall stiffness and there is a concomitant increase in tremor on movement.

The Diversity of Chemoreceptors

Abstract: Diversity is defined in the Oxford English Dictionary as “The condition or quality of being diverse, different or varied; difference, unlikeness.”

Holocene debris cone evolution in Glen Etive, Western Grampian Highlands, Scotland

Abstract: Stratigraphic investigations, radiocarbon dating of buried soils and pollen analyses were employed to reconstruct the history of development of a fluvially-reworked debris cone in Glen Etive. Paraglacial aggradation of debris flow deposits resulted in cone formation between c. 10000 yr B.P. and c. 4000 yr B.P. until supplies of sediment from upslope were effectively exhausted and debris flow activity ceased. There ensued a prolonged period of stability and soil development on the cone surface. This ended sometime after c. 550 yr B.P. when human interference (including burning) resulted in destruction of the natural vegetation cover and triggered fluvial incision and the development of an alluvial fan of reworked sediment that buried the lower part of the debris cone. The wider implications of these findings are discussed.

The origins of Freemasonry

Abstract: List of plates Preface List of abbreviations and conventions 1. Introduction 2. The medieval contribution 3. William Schaw, master of works and general warden 4. The Sinclairs of Roslin and the masters of works 5. The Renaissance contribution 6. Rituals of identification and initiation 7. Sir Robert Moray: masonry, symbolism and ethics 8. The early Scottish lodges 9. Early Scottish and English freemasonry Appendix Bibliographical note Index.

Selective attention, visual laterality, awareness, and perceiving the meaning of parafoveally presented words

Abstract: Four experiments are reported investigating the effect of selective attention on the semantic encoding of parafoveally presented words. In Experiments 1 and 2 a right visual field (RVF) performance bias was found when subjects attended to words that could appear either left or right of centre (attend-side condition). When subjects attended centrally and ignored lateral distractor words (attendcentre condition) there was an inhibitory effect of word meaning from left visual field (LVF) distractors. Both inhibitory and facilitatory effects of semantic category were observed from unattended words in Experiments 3 and 4. The pattern of effects depended upon the direction of spatial bias in an attend-side condition. Both kinds of effect occurred even for subjects who were unable to make consciously directed semantic category decisions to words at the same eccentricity (4°) and exposure time (15 msec) as ignored distractors in the attend-centre condition. Implications of these findings for theories of selective...

Event related potentials from closed head injury patients in an auditory "oddball" task: evidence of dysfunction in stimulus categorisation.

Abstract: Event-related potentials (ERPs) were recorded from 19 closed head injury (CHI) patients, at least 6 months after injury, and an equal number of control subjects, during a task requiring the covert counting of rare auditory "target" stimuli against a background of frequent "non-targets". In both groups, ERPs to targets contained enhanced frontal N2 and parietal P3 components. N2 was larger in amplitude in the CHI patients than in the controls, and its peak latency was delayed. P3 amplitude was smaller in the patients, but its latency was not significantly different from that of the control group. The delay in N2 latency is interpreted as evidence of an increase in the time needed to achieve stimulus categorisation in CHI patients. The larger N2s in this group are thought to reflect the additional cognitive effort required after CHI to cope with the task. The negative findings with respect to P3 latency suggest that this may be a less sensitive measure of information-processing efficiency in this task than the latency of N2.

A reinterpretation of the Lateglacial environmental history of the Isle of Skye, Inner Hebrides, Scotland

Abstract: This paper presents a major revision of the Late Devensian Lateglacial environmental history of the Isle of Skye, Scotland, based upon a combination of geomorphological, biostratigraphical and radiocarbon evidence. The distribution of glacial and periglacial landforms, and of raised shorelines, suggests that there was only one extensive readvance of local glaciers in southern Skye following the wastage of the Late Devensian ice sheet. Pollen-stratigraphic evidence from 10 sites inside and 4 sites outside the mapped ice limits indicates that this readvance occurred during the Loch Lomond Stadial. At that time over 180km2 of the uplands of south-central Skye were covered by glacier ice, a much more extensive glaciation than previously envisaged. Palynological evidence from four Lateglacial profiles implies that degree of exposure to strong westerly winds was the principal factor determing vegetational contrasts on the island, and that regional differences in vegetational type were less pronounced than has hitherto been suggested. The glacial and palaeobotanical reconstructions reported here are more compatible with Lateglacial data from the Scottish mainland and Hebridean islands than were the previously-published accounts for the Isle of Skye.

Fiber Fox–Smith resonators: application to single-longitudinal-mode operation of fiber lasers

Abstract: An optical-fiber Fox–Smith resonator was demonstrated for the first time to our knowledge. It was applied to obtain single-longitudinal-mode operation from an erbium-doped fiber laser. Both the passive performance and the active performance of the device are studied in detail. Good agreement is found between theoretical and experimental results.

Safe browsing in a strongly typed persistent environment

Abstract: The need to examine data structures often occurs in programming language and database management systems. In this paper we describe how a browser for a strongly typed programming language ( PS-algol ) may be written in a type secure manner in a closed persistent environment. This is achieved without resorting to magic or having to break the type rules of the language by exploiting a compiler that is a object with full civil rights in the environment. The use of impact of such an object is discussed. Safe Browsing in a Strongly Typed Persistent Environment Page 3

DNA sequence of the adenovirus type 41 hexon gene and predicted structure of the protein.

Abstract: Summary The gene for the major capsid protein (hexon) of human adenovirus type 41 (Ad41) has been isolated and the complete DNA sequence determined. Comparison of the predicted amino acid sequence with hexons from human Ad2 and Ad5 and bovine adenovirus type 3 reveals regions of high homology at the N and C termini separated by a central region of low homology. Fitting of the Ad41 hexon sequence to the known three-dimensional structure of the Ad2 hexon demonstrates that both hexons have a common architecture. Regions of the hexon which in the trimer constitute the pseudohexagonal base are highly conserved, with the major amino acid changes concentrated in the domains forming the triangular towers which represent the surface of the capsid. Changes in the Ad41 towers therefore permit the virus to present a unique surface to the environment while conservation of residues in the base maintains the integrity of hexon-hexon contacts. A striking difference is the absence in the Ad41 sequence of 32 amino acids which are present in the Ad2 sequence. In Ad2 this region is highly charged and may be responsible for pH-induced conformational changes within the virus capsid. The DNA sequence in the region surrounding the Ad41 hexon gene was also determined and revealed an open reading frame which appeared to code for the homologue of the Ad2-coded endoprotease. Comparison of the predicted amino acid sequences of the Ad41 and Ad2 proteins revealed a high degree of homology suggesting that this protein may have an important role in the infectious cycle of the virus.