Showing papers by "Royal Holloway, University of London published in 1996"

An Introduction to Psychological Tests and Scales

Abstract: In its first edition this book successfully enabled readers, with little or no prior knowledge of computing or statistics, to develop reliable and valid tests and scales for assessment or research purposes. In this edition, the author has thoroughly updated the text to include new recent advances in computer software and provide information on relevant internet resources. The book contains detailed guidelines for locating and constructing psychological measures, including descriptions of popular psychological measures and step-by-step instructions for composing a measure, entering data and computing reliability and validity of test results. Advanced techniques such as factor analysis, analysis of covariance and multiple regression analysis are presented for the beginner.An Introduction to Psychological Tests and Scales provides a clear, concise and jargon-free primer for all those embarking in fieldwork or research analysis. It will be an invaluable tool for undergraduates and postgraduates in psychology and a useful text for students and professionals in related disciplines.

The cortical topography of human swallowing musculature in health and disease

Abstract: Because no detailed information exists regarding the topographic representation of swallowing musculature on the human cerebral cortex in health or disease, we used transcranial magnetic stimulation to study the cortical topography of human oral, pharyngeal and esophageal musculature in 20 healthy individuals and the topography of pharyngeal musculature in two stroke patients, one with and one without dysphagia. Our results demonstrate that swallowing musculature is discretely and somatotopically represented on the motor and premotor cortex of both hemispheres but displays interhemispheric asymmetry, independent of handedness. Following stroke, dysphagia appeared to be associated with smaller pharyngeal representation on the intact hemisphere, which increases in size with recovery of swallowing.

Anxiety, depression, and the anticipation of future positive and negative experiences.

Abstract: An experiment is reported that attempts to distinguish between anxious and depressive future thinking in terms of anticipation of future positive and future negative experiences. Anxious, mixed (anxious-depressed), and control participants were given an adapted verbal fluency paradigm to examine the ease with which they could think of future positive and negative personal experiences. Anxious participants differed from controls only in anticipating more future negative experiences; mixed participants showed both greater anticipation of negative experiences and reduced anticipation of positive experiences. Self-report measures of hopelessness and worry followed a similar pattern to future positive and future negative anticipation, respectively. The results are discussed in terms of the distinction between positive affect and negative affect (D. Watson, L. A. Clark, & G. Carey, 1988).

Insight into the nature of the ocean-continent transition off West Iberia from a deep multichannel seismic reflection profile

Abstract: A high-quality multichannel seismic reflection profile across the West Iberia margin confirms the existence of a 130-km-wide transition zone between tilted continental fault blocks and unequivocal oceanic crust. The zone is characterized by a 1.0–2.5-km-thick seismically unreflective upper basement layer lying over reflective basement that contains major landward-dipping reflectors that mostly truncate against the base of the upper layer and penetrate to depths of 10–19 km below the basement surface, and minor seaward-dipping reflectors. Moho reflections are absent in this zone. We suggest that the unreflective layer represents tectonically exposed upper mantle that has undergone extensive serpentinization enhanced by vigorous seawater circulation. About 40 km farther north the transition zone narrows to 35 km and the unreflective layer is less continuous and widespread.

Syntectonic burial and post-tectonic exhumation of the southern Pyrenees foreland fold–thrust belt

Abstract: In the Oligocene to earliest Miocene the entire southern Pyrenean foreland fold and thrust belt was backfilled and buried in up to 3 km of syntectonic continental conglomerates from the range9s own erosional debris. Then, starting in the mid to late Miocene, the Pyrenees were exhumed by erosional excavation to their present relief. A model is proposed for this unusual development whereby late Eocene–Oligocene tectonic uplift of the margins of the Ebro basin raised local base level and blocked normal dispersal of erosional debris to adjacent oceans, thus causing the basin to fill then backfill northwards across the entire southern flank of the Pyrenees. Subsequent Miocene rifting of the Catalan Mediterranean margin, and the Messinian salinity crisis, lowered base level allowing the Ebro River to cut headward, capture the Ebro basin, and re-excavate the Pyrenees.

Temporal grouping effects in immediate recall: A working memory analysis

Abstract: The presence of temporal pauses during list presentation can markedly improve immediate memory for a sequence of verbal items. A series of experiments analysed this effect using Baddeley's (1986) model of working memory. Experiment 1 showed that the effect of temporal grouping on memory for visual sequences was removed by either articulatory suppression or reciting random digits. Experiment 2 indicated that effects of temporal grouping were insensitive to the word length of the items. Experiment 3 showed that articulatory suppression did not remove the temporal grouping effect for auditory lists. Experiment 4 showed that the temporal grouping effect was insensitive to the phonemic similarity of the items. The effects of concurrent articulation suggest that grouping influences the phonological loop component of working memory. However, the working memory model is insufficiently well specified to account for the insensitivity of grouping effects to word length and phonemic similarity. The main findings could be simulated by a connectionist model of the phonological loop, which invokes a context timing signal (Burgess & Hitch, 1992, in press), This assumed that pauses during list presentation affect the timing signal in a similar way to the pause before list presentation and made some novel predictions.

Influence of sea-floor spreading on the global hydrothermal vent fauna

Abstract: ONE remarkable discovery of recent decades is the presence of hundreds of unusual species, including fourteen new families, at hydrothermal vents. These animals, unknown from other habitats, live in extreme chemical and thermal conditions around vents on spreading centres of the mid-ocean ridges and back-arc basins. Chemosynthesis provides an in situ energy source for the thriving vent fauna. This habitat has existed through the Phanerozoic1,2 and probably since the Archaean, thus providing sites for long-term adaptation. We now test the hypothesis that animal distribution among hydrothermal vents is related to tectonic plate history3,4. The predominant migration pathway is most likely to occur along mid-ocean ridges rather than by shortest oceanic routes. Similarity analyses suggest that the distribution patterns of today's vent fauna display the strong imprint of the timing and geometry of ancient plate boundaries. Study of past ridge geometry provides a method to predict relationships among vent communities yet to be discovered.

Differential distribution of ferulic acid to the major plasma constituents in relation to its potential as an antioxidant

Abstract: The hydroxycinnamates, intermediates in the phenylpropanoid synthetic pathway, are effective in enhancing the resistance of low-density lipoprotein (LDL) to oxidation in the order caffeic acid > ferulic acid > p-coumaric acid. It is unclear whether the mode of action of ferulic acid as an antioxidant is based on its activities in the aqueous or the lipophilic phase. Partitioning of 14C-labelled ferulic acid into plasma and its components, LDL and the albumin-rich fractions, has been studied under conditions of maximum aqueous solubility. The majority of ferulic acid associates with the albumin-rich fraction of the plasma, although a proportion is also found to partition between the LDL and aqueous phases; however, ferulic acid does not associate with the lipid portion of the LDL particle, suggesting that it exerts its antioxidant properties from the aqueous phase. This is of particular interest since the results demonstrate that ferulic acid is a more effective antioxidant against LDL oxidation than the hydrophilic antioxidant ascorbic acid.

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

Abstract: In pollen development, a dramatic reorganization of the actin cytoskeleton takes place during the passage of the pollen grain into dormancy and on activation of pollen tube growth. A role for actin-binding proteins is implicated and we report here the identification of a small gene family in maize that encodes actin depolymerizing factor (ADF)-like proteins. The ADF group of proteins are believed to control actin polymerization and depolymerization in response to both intracellular and extracellular signals. Two of the maize genes ZmABP1 and ZmABP2 are expressed specifically in pollen and germinating pollen suggesting that the protein products may be involved in pollen actin reorganization. A third gene, ZmABP3, encodes a protein only 56% and 58% identical to ZmABP1 and ZmABP2, respectively, and its expression is suppressed in pollen and germinated pollen. The fundamental biochemical characteristics of the ZmABP proteins has been elucidated using bacterially expressed ZmABP3 protein. This has the ability to bind monomeric actin (G-actin) and filamentous actin (F-actin). Moreover, it decreases the viscosity of polymerized actin solutions consistent with an ability to depolymerize filaments. These biochemical characteristics, taken together with the sequence comparisons, support the inclusion of the ZmABP proteins in the ADF group.

Influence of temperature and humidity on populations of Callosobruchus maculatus (Coleoptera: Bruchidae) and its parasitoid Dinarmus basalis (Pteromalidae) in two climatic zones of Burkina Faso

Abstract: Callosobruchus maculatus (Fabricius) develops in the seeds of Vigna unguiculata in the Sahel region of Africa. The reproductive activity of this species and the development of its offspring were studied during the dry season at Ouagadougou and Bobo Dioulasso (Burkina Faso), two zones with different climatic conditions. The length of imaginal life of the females and the developmental time varied with changes in climatic conditions, the lowest values for both parameters being found at the end of the dry season when temperature and humidity increased. In the two zones, variations in the density of the bruchid populations have been studied in experimental stores. The density of the bruchid population was low at the beginning of the study and increased when temperature and humidity rose. The introduction of Dinarmus basalis (Rondani) adults to the stores caused a significant reduction in the numbers of C. maculatus adults. The density of the D. basalis populations was low from December to February and increased when temperatures and then humidity became higher. The increase of the D. basalis population and the rate of parasitism were greater at Bobo Dioulasso than at Ouagadougou. Laboratory studies have demonstrated that fecundity, duration of adult life and developmental times depend on humidity. This study has shown the importance of local climatic conditions on parasitoid reproduction and development and also in the control of bruchid populations in stores.

Intrusive memories in depression: an index of schema activation?

Abstract: A sample of 31 male and female depressed patients was interviewed to investigate spontaneous, intrusive memories of immediate and past life events Previous findings that depressed patients experience high frequency intrusive memories were confirmed, as was an association between intrusive memories of childhood abuse and severity of depression Patients reported intrusive memories for a variety of other events, particularly involving illness and death Limited support was obtained for the hypotheses that the course of depression would be related to the activation of negative memories, and that immediate life events would trigger the activation of memories of similar events from the past

The geochemistry and petrogenesis of the late-Cretaceous picrites and basalts of Curaçao, Netherlands Antilles: a remnant of an oceanic plateau

Abstract: The island of Curacao in the southern Caribbean Sea is composed mainly of a thick sequence (>5 km) of pillow lavas, grading upwards from picrites at the base of the exposed section, to basalts nearer the top. Modelling suggests that picrites are related to the basalts by fractional crystallisation. Initial radiogenic isotope ratios of the picrites have a restricted compositional range: ɛNd=+6.1 to +6.6, 87Sr/86Sr=0.70296–0.70319; whereas the basalts display a wider range of compositions: ɛNd=+6.6 to +7.6, 87Sr/86Sr=0.70321–0.70671. This variation in isotope ratios between basalts and picrites may be due to the assimilation of altered oceanic crust (or possibly partial melts of such crust) by a picritic magma along with fractional crystallisation. The relatively narrow range of Nd and Pb isotopic compositions in the Curacao lavas suggests either that the source region was homogeneous, or that melts from a heterogeneous mantle source were well mixed before eruption. Chondritic to slightly light rare earth element enriched patterns, combined with long-term light rare earth element depletion (positive ɛNd), suggest that the lavas were formed by polybaric melting of spinel lherzolite, with small a contribution from garnet lherzolite melts. High-MgO lavas, the absence of a subduction related chemistry, and the chemical similarity to other oceanic plateaux, suggest a mantle plume origin for the Curacao lava succession. The Curacao volcanic sequence is part of an oceanic plateau formed at about 88–90 Ma, fragments of which are dispersed around the Caribbean as well as being obducted onto the western margin of Colombia and Ecuador. The occurrence of high-Mg lavas throughout this Cretaceous Caribbean–Colombian igneous province requires anomalously hot mantle (>200° C hotter than ambient upper mantle) over a large part of a putative plume head, which is inconsistent with some mantle plume models.

Evolutionary Changes in a Song Control Area of the Brain (HVC) are Associated with Evolutionary Changes in Song Repertoire among European Warblers (Sylviidae)

Abstract: Determining relations between brain structure and function is a principal focus of evolutionary neurobiology. Here we investigate covariation between singing behaviour and the neuroanatomy in eight species of sylviid warblers from the closely related Acrocephalus and Locustella genera. We found a significant positive correlation between repertoire size and the volume of the higher vocal centre after controlling for variation in brain size and phylogenetic relatedness across species. This group is of particular interest, as earlier work has shown that an increase in male song complexity (as measured by syllable repertoire size) is caused by sexual selection pressure acting through female choice. Thus, in males of Acrocephalus species (which have complex songs), sexual selection appears to have led to increases in both syllable repertoire size and the relative volume of the higher vocal centre. In contrast, Locustella species have very simple songs, and repertoire size and the relative volume of the higher vocal centre remain small in males of these species. These results indicate that sexual selection may have shaped the evolution of a particular behavioural trait (song) by altering the relevant controlling area of the brain (higher vocal centre).

Affect, Emotional Disorder, and Future-directed Thinking

Abstract: Affect, it has been argued, can be divided into two higher order dimensions of positive affect (PA) and negative affect (NA) (Watson, L.A. Clark, & Tellegen, 1988). This framework has been used to provide an analysis of depression and anxiety, and has also been integrated with the account of aversive and appetitive motivational systems outlined by Gray (1987) and others (L.A. Clark, Watson, & Mineka, 1994). The present studies represent an attempt to extend this framework to include patterns of future-directed thinking. Two studies are reported in which a sample of students completed measures of PA and NA, depression and anxiety, hopelessness and worry, and positive and negative expectancies. Factor analysis revealed two clear factors. The first factor had loadings from NA, anxiety, worry, negative expectancies, and depression; the smaller second factor had loadings from PA and positive expectancies, and negative loadings from hopelessness and depression. The results support the existence of two basic cog...

Why are Dormice rare? A case study in conservation biology

Abstract: In the last 100 years, the Dormouse Muscardinus avellcmarius has disappeared from about half its geographical range in Britain. Evidence is presented which indicates that declining range and numbers are due to a complex interplay of factors which include fragmentation, deterioration and loss of specialized habitat. The Dormouse is unusual in being a relatively A-selected small mammal, with exacting ecological requirements which render it very vulnerable, particularly to habitat fragmentation. The Dormouse is also sensitive to climate, both directly and probably indirectly through the effects of weather on the timing and abundance of food (insects, flowers and fruits). Combined with low population density and low intrinsic rate of population increase, this makes the Dormouse highly vulnerable, not just to absolute climatic measures (e.g. temperature, rainfall), but especially to climatic stochasticity, particularly at the edge of its range. There are strong associations between the distribution and changing status of the Dormouse and various climatic parameters, and clear parallels with other climate-sensitive taxa, notably bats and butterflies. The Dormouse is a very specialized species, highly sensitive to environmental change, resulting in its piecemeal, progressive extinction, particularly in northern counties. It is likely to be a very sensitive indicator species for monitoring future changing environments and an excellent model for studying the effects of habitat fragmentation, climatic shifts and climatic stochasticity.

Comments on the S/KEY user authentication scheme

Abstract: We give a critical analysis of the security properties of the S/KEY user authentication system.

Social factors and comorbidity of depressive and anxiety disorders

Abstract: Differences in rates of depression across and between populations can be considerable and are largely determined by psychosocial factors. Such findings have important implications for comorbidity. On the basis of multiplying independent probabilities, the proportion of comorbid conditions increases as base rates of the disorders increase in a population. If such a chance combination has clinical implications, it would appear to be a "fact" of significance irrespective of biological underpinnings. In a recent survey of 404 women living with at least one child in an inner-city area, the rate of both anxiety and depression was highly related to the childhood experiences of neglect and abuse. However, adversity in adult life (e.g. widowhood or divorce), which might be expected to relate to current stressors, was only related to the rate of depression. The two risk factors had a considerable impact on comorbidity by increasing the rate of each disorder and thus the probability of their occurring together. They had a lesser impact as "common antecedents". If both influences are considered, such adversity explains around half of the comorbidity. This is a conservative estimate of the impact of psychosocial factors.