Showing papers by "University of St Andrews published in 1995"
TL;DR: In this article, the authors show that the presence of non-thermal electrons may change the nature of ion sound solitary structures and allow the existence of structures very like those observed.
Abstract: Solitary electrostatic structures involving density depletions have been observed in the upper ionosphere by the Freja satellite [Dovner et al., 1994]. If these are interpreted as ion sound solitons, the difficulty arises that the standard Korteweg-de Vries description predicts structures with enhanced rather than depleted density. Here we show that the presence of non-thermal electrons may change the nature of ion sound solitary structures and allow the existence of structures very like those observed.
757 citations
Book•
01 Jan 1995TL;DR: Engaging characters as discussed by the authors discusses emotional responses to films, integrating them into a theory of engagement with characters in cinematic and literary fictions, including The Accused, Hitchcock, The Man Who Knew Too Much and Saboteur.
Abstract: Thrillers, weepies, horror movies, and melodramas evoke characteristic kinds of emotional response, yet emotion is not much examined by film or literary theory. Engaging Characters discusses emotional responses to films, integrating them into a theory of engagement (`identification') with characters in cinematic and literary fictions. Films and filmmakers discussed include The Accused; Hitchcock (including detailed analyses of The Man Who Knew Too Much and Saboteur); Godard; Ruiz; Bunuel's That Obscure Object of Desire; Dovzhenko's Arsenal; Preminger's Daisy Kenyon; Bresson's L'Argent; Eisenstein's Strike; and Melville's Le Doulos.
461 citations
TL;DR: Following the appearance of I kappa B alpha in the nuclei of activated cells, a dramatic reduction in the amount of nuclear p50 occurs, suggesting that NF-kappa B-I kappaB alpha complexes are cleared from the nucleus.
Abstract: The transcription factor NF-kappa B is exploited by many viruses, including the human immunodeficiency virus, for expression of viral genes, but its primary role appears to be in the rapid induction of cellular genes during immune and inflammatory responses. The inhibitor protein I kappa B alpha maintains NF-kappa B in an inactive form in the cytoplasms of unstimulated cells, but upon cell activation, I kappa B alpha is rapidly degraded, leading to nuclear translocation of free NF-kappa B. However, NF-kappa B-dependent transcription of the I kappa B alpha gene leads to rapid resynthesis of the I kappa B alpha protein and inhibition of NF-kappa B-dependent transcription. Here we demonstrate a new regulatory function of I kappa B alpha exerted on NF-kappa B in the nuclear compartment. Although normally found in the cytoplasm, I kappa B alpha, newly synthesized in response to tumor necrosis factor or interleukin I, is transported to the nucleus. In the nucleus I kappa B alpha associates with the p50 and p65 subunits of NF-kappa B, inhibiting DNA binding of the transcription factor. Furthermore, nuclear expression of I kappa B alpha correlates with transcription termination of transfected NF-kappa B-dependent luciferase genes. Following the appearance of I kappa B alpha in the nuclei of activated cells, a dramatic reduction in the amount of nuclear p50 occurs, suggesting that NF-kappa B-I kappa B alpha complexes are cleared from the nucleus.
452 citations
Book•
23 Mar 1995TL;DR: In this article, the limits of fossil evidence are discussed and a theory of mind is proposed to understand how animals learn and why animals learn better in social groups than in the wild.
Abstract: Introduction: the limits of fossil evidence 1. Taxonomy and the reconstruction of evolution 2. What is intelligence and what is it for? 3. How animals learn 4. Why animals learn better in social groups 5. Imitative behaviour in animals 6. Understanding how things work 7. Understanding minds: doing and seeing, knowing and thinking 8. What use is a theory of mind? 9. Planning and thinking ahead 10. Apes and language 11. Food for thought 12. Machiavellian intelligence 13. Testing the theories 14. Taking stock
444 citations
TL;DR: The results show that GDNF promotes the survival of multiple PNS and CNS neurons and suggest thatGDNF may be important for regulating the survive of various populations of neurons at different stages of their development.
441 citations
TL;DR: Investigating visual cues to age by using facial composites which blend shape and colour information from multiple faces provided an empirical definition of facial changes with age that are biologically consistent across a sample population.
Abstract: This study investigated visual cues to age by using facial composites which blend shape and colour information from multiple faces. Baseline measurements showed that perceived age of adult male faces is on average an accurate index of their chronological age over the age range 20-60 years. Composite images were made from multiple images of different faces by averaging face shape and then blending red, green and blue intensity (RGB colour) across comparable pixels. The perceived age of these composite or blended images depended on the age bracket of the component faces. Blended faces were, however, rated younger than their component faces, a trend that became more marked with increased component age. The techniques used provide an empirical definition of facial changes with age that are biologically consistent across a sample population. The perceived age of a blend of old faces was increased by exaggerating the RGB colour differences of each pixel relative to a blend of young faces. This effect on perceived age was not attributable to enhanced contrast or colour saturation. Age-related visual cues defined from the differences between blends of young and old faces were applied to individual faces. These transformations increased perceived age.
436 citations
TL;DR: The review indicates that the PPTg is less concerned with the induction of locomotion and more concerned with relating reinforcement with motor output from the dorsal striatum, and forms a 'subsidiary circuit', returning information to striatal circuitry.
325 citations
TL;DR: The radical nature of NO cannot account for its cytotoxicity, but its reaction with superoxide to form peroxynitite and highly reactive hydroxyl radicals may be important in this context.
316 citations
TL;DR: In this article, it was shown that the rotation of the Poynting vector of a Laguerre-Gaussian laser mode is proportional to the Gouy phase and for most cases of interest, rotates through less than one revolution in reaching the far field.
296 citations
TL;DR: The "Landmark Task" is designed to tease apart two major factors in determining line bisection errors in spatial neglect: one whose general nature is perceptual, the other whose nature is motor.
TL;DR: The results indicate that the availability of high quality crustacean prey may limit the production of fishes, and that fishes are likely to compete diffusively for crustACEan prey.
TL;DR: In two recognition memory tests subjects made initial old/new judgements and subsequently judged whether 'old' words had been presented auditorily or visually at study, consistent with the hypothesis that the old/ new effect is associated with recognition memory based on recollection of the study episode, rather than familiarity.
01 Jul 1995
TL;DR: The motivation for orthogonal persistence is reviewed, the concepts for integrating programming languages and databases through the persistence abstraction, and their benefits, are given and the technology to support persistence is discussed.
Abstract: Persistent Application Systems (PASs) are of increasing social and economic importance. They have the potential to be long-lived, concurrently accessed, and consist of large bodies of data and programs. Typical examples of PASs are CAD/CAM systems, office automation, CASE tools, software engineering environments, and patient-care support systems in hospitals. Orthogonally persistent object systems are intended to provide improved support for the design, construction, maintenance, and operation of PASs. Persistence abstraction allows the creation and manipulation of data in a manner that is independent of its lifetime, thereby integrating the database view of information with the programming language view. This yields a number of advantages in terms of orthogonal design and programmer productivity which are beneficial for PASs. Design principles have been proposed for persistent systems. By following these principles, languages that provide persistence as a basic abstraction have been developed. In this paper, the motivation for orthogonal persistence is reviewed along with the above mentioned design principles. The concepts for integrating programming languages and databases through the persistence abstraction, and their benefits, are given. The technology to support persistence, the achievements, and future directions of persistence research are then discussed.
TL;DR: A theoretical and experimental investigation has been carried out into the viability of V-type, ε-Lambda-type and cascade systems within rubidium for the observation of electromagnetically-induced transparency (EIT) as discussed by the authors.
Abstract: A theoretical and experimental investigation has been carried out into the viability of V-type, \ensuremath{\Lambda}-type, and cascade systems within rubidium for the observation of electromagnetically-induced transparency (EIT). A \ensuremath{\Lambda}-type system is also discussed where EIT is induced on a two-photon transition. Continuous-wave single-frequency titanium sapphire lasers have been employed to provide the applied optical fields. It is found that systems that have a strong coupling field resonant with the 5${\mathit{S}}_{1/2}$ ground state suffer from complicating optical pumping mechanisms that tend to mask EIT windows. It is also found that wavelength matching of the applied optical fields enhances the observation of EIT since this results in a reduced residual Doppler linewidth of the atomic system.
TL;DR: These regression equations can be used as models to predict the production of macrofauna, crustaceans and small fishes at unexamined sites when predictions were compared with estimates of annual production at the eight sites previously examined in Western Port.
01 Jan 1995
TL;DR: The results show that NT3 can signal through TrkA and TrkB in neurons at certain stages of development and may explain why the phenotype of NT3−/− mice is more severe than that of trkC− /− mice.
Abstract: Neurotrophins promote neuronal survival by signalling through Trk receptor tyrosine kinases: nerve growth factor signals through TrkA, brain-derived neurotrophic factor (BDNF) and neurotrophin (NT)4 through TrkB and NT3 through TrkC. Although studies in some, but not all, cell lines indicate that NT3 can also signal through TrkA and TrkB, it is not known if such signalling can occur in neurons. We show that NT3 can promote the in vitro survival of sensory and sympathetic neurons isolated from embryos that are homozygous for a null mutation in the trkC gene. During the mid-embryonic period, NT3 promoted the survival of as many trigeminal and nodose neurons as the preferred neurotrophins, NGF and BDNF. However, later in development, these neurons lost their ability to respond to NT3. NT3 also promoted the survival of almost all sympathetic neurons, but no decrease in effectiveness was observed during development. Trigeminal neurons from trkC-/- trkA-/- embryos did not respond to NT3 and nodose neurons from trkB-/- embryos likewise failed to respond to NT3. These results show that NT3 can signal through TrkA and TrkB in neurons at certain stages of development and may explain why the phenotype of NT3-/- mice is more severe than that of trkC-/- mice.
TL;DR: Seasonal data indicate that when the production of crustaceans was at its lowest during May, populations of small fishes were rapidly declining in Western Port, either by dying or emigrating, and it is postulated that these factors are causally linked.
TL;DR: It is suggested that size perception may be partially determined by a representational system that is anatomically centred in the parieto-temporal region of the brain in neglect patients.
TL;DR: Experimental overexpression of Bcl-2 prevents the death of neurones deprived of particular neurotrophic factors in vitro, and rescues developing neurones that would otherwise die in vivo.
TL;DR: Attention is focused on cell proliferation and support is added to earlier suggestions that a primary function of YB proteins is to help activate growth-associated genes.
Abstract: Members of the Y-box (YB) family of transcription factors are expressed in a wide range of cell types and are implicated in the regulation of a rapidly increasing number of genes. Although the biological activities of YB proteins appear to be varied, distinct patterns, relating to the timing of their expression and the identity of their target genes, are beginning to emerge. A recent report by Ito et al.(1) focusses attention on cell proliferation and adds support to earlier suggestions(2, 3) that a primary function of YB proteins is to help activate growth-associated genes.
01 Jan 1995
TL;DR: Quantitative trait and enzyme electrophoresis analysis was used to assess the pattern of variation within and among five short-lived taxa of Conyza and suggests that the five taxa differentiated genetically in their native range prior to their introduction in Europe.
Abstract: The genus Conyza (Asteraceae) represents one of the foremost examples of intercontinental plant invasions from the New World to the Old World that has resulted in a number of taxonomic problems owing to the dearth of knowledge concerning the biosystematics of the genus. In this study, quantitative trait and enzyme electrophoresis analysis was used to assess the pattern of variation within and among five short-lived taxa of Conyza (C. blakei, C. bonariensis, C. canadensis, C.floribunda, C. sumatrensis), introduced into Europe, and to test the hypothesis of a recent hybrid origin of C. floribunda. The five taxa exhibit marked differences in morphological and life-history characteristics that are concordant with divergence in genes encoding isozymes. In addition, a recent hybrid origin of C. floribunda is clearly not supported by either quantitative or electrophoretic data. These findings suggest that the five taxa differentiated genetically in their native range prior to their introduction in Europe. As formerly suggested by Arthur Cronquist (Bulletin of the Torrey Botanical Club 70: 629-632, 1943), C. canadensis appears to be more closely related to the genus Erigeron than the other taxa. The electrophoretic results also confirm that this particular species is diploid, while the presence of multiple bands and fixed heterozygosity demonstrates that the other Conyza taxa are all genetic allopolyploids. Both quantitative and electrophoretic data suggest the presence of two groups among the polyploid taxa: one comprising C. bonariensis and C. sumatrensis, the other C. blakei and C.floribunda. The latter grouping is supported by the observation that C. blakei and C. floribunda, both native to Argentina, exhibit a striking ability to shift from semelparous to iteroparous reproduction, while the other taxa are strictly semelparous.
TL;DR: Findings indicate that, as indexed by ERF's, repetition effects both within- and across-modality are influenced by lexical status.
Abstract: The effects on event-related potentials (ERPs) of within-and across-modality repetition of words and nonwords were investigated. In Experiment 1, subjects detected occasional animal names embedded in a series of words. AU items were equally likely to be presented auditorily or visually. Some words were repetitions, either within-or across-modality, of words presented six items previously. Visual-visual repetition evoked a sustained positive shift, which onset around 250 msec and comprised two topographically and temporally distinct components. Auditory-visual repetition modulated only the later of these two components. For auditory EMS, within-and across-modality repetition evoked effects with similar onset latencies. The within-modality effect was initially the larger, but only at posterior sites. In Experiment 2, critical items were auditory and visual nonwords, and target items were auditory words and visual pseudohomophones. Visual-visual nonword repetition effects onset around 450 msec, and demonstrated a more anterior scalp distribution than those evoked by auditory-visual repetition. Visual-auditory repetition evoked only a small, late-onsetting effect, whereas auditory-auditory repetition evoked an effect that, at parietal sites only, was almost equivalent to that from the analogous condition of Experiment 1. These findings indicate that, as indexed by ERF's, repetition effects both within-and across-modality are influenced by lexical status. Possible parallels with the effects of word and nonword repetition on behavioral variables are discussed.
TL;DR: The results show that the interaction between word frequency and old/new differences in ERPs does not arise because of a confound between frequency and the probability of recollection, and suggest that recollection is better conceived of as a graded, rather than as an all-or-none phenomenon.
TL;DR: Functional analysis of V8 cleavage products indicates that I kappa B alpha molecules lacking the N-terminal region can interact with and inhibit the DNA-binding activity of the p65 subunit of NF-kappa B, whereas IKappa Balpha molecules which lack both the N and C-terminals are incapable of doing so.
Abstract: The DNA-binding activity and cellular distribution of the transcription factor NF-kappa B are regulated by the inhibitor protein I kappa B alpha. I kappa B alpha belongs to a family of proteins that contain multiple repeats of a 30- to 35-amino-acid sequence that was initially recognized in the erythrocyte protein ankyrin. Partial proteolysis has been used to study the domain structure of I kappa B alpha and to determine the sites at which it interacts with NF-kappa B. The data reveal a tripartite structure for I kappa B alpha in which a central, protease-resistant domain composed of five ankyrin repeats is flanked by an unstructured N-terminal extension and a compact, highly acidic C-terminal domain that is connected to the core of the protein by a flexible linker. Functional analysis of V8 cleavage products indicates that I kappa B alpha molecules lacking the N-terminal region can interact with and inhibit the DNA-binding activity of the p65 subunit of NF-kappa B, whereas I kappa B alpha molecules which lack both the N- and C-terminal regions are incapable of doing so. Protease cleavage of the N terminus of I kappa B alpha was unaffected by the presence of the p65 subunit of NF-kappa B, whereas bound p65 blocked cleavage of the flexible linker connecting the C-terminal domain to the ankyrin repeat-containing core of the protein. This linker region is highly conserved within the human, rat, pig, and chicken homologs of I kappa B alpha, and while it has been suggested that it represents a sixth ankyrin repeat, it is also likely that this is a flexible region of the protein that interacts with NF-kappa B.
TL;DR: The unusual oligosaccharide structures described here, particularly the potentially immunodominant oligofucosyl moieties, are most likely responsible for the known potency of GCX in modulating various immune responses including complement activation, B cell mitogenesis, and delayed type hypersensitivity in schistosomiasis.
TL;DR: In this article, the authors used diffusion profiles and a hydrous, yet slightly H 2 O-undersaturated melt composition to produce diffusion profiles of tin in hydrous silicate melts adjacent to cassiterite crystals.