Showing papers by "Royal Holloway, University of London published in 2004"

Lexique 2: a new French lexical database.

Abstract: In this article, we present a new lexical database for French: Lexique. In addition to classical word information such as gender, number, and grammatical category, Lexique includes a series of interesting new characteristics. First, word frequencies are based on two cues: a contemporary corpus of texts and the number of Web pages containing the word. Second, the database is split into a graphemic table with all the relevant frequencies, a table structured around lemmas (particularly interesting for the study of the inflectional family), and a table about surface frequency cues. Third, Lexique is distributed under a GNU-like license, allowing people to contribute to it. Finally, a metasearch engine, Open Lexique, has been developed so that new databases can be added very easily to the existing ones. Lexique can either be downloaded or interrogated freely from http://www.lexique.org.

The relation of depression and anxiety to life‐stress and achievement in students

Abstract: Objectives: An apparent increase in seriously disturbed students consulting student health services in the UK has led to concern that increasing financial difficulties and other outside pressures may affect student mental health and academic performance. The current research investigated whether student anxiety and depression increases after college entry, the extent to which adverse life experiences contribute to any increases, and the impact of adversity, anxiety and depression on exam performance. Method: 351 UK-domiciled undergraduates completed questionnaires one month before university entry and mid-course. The Hospital Anxiety and Depression Scale (HADS: Zigmond & Snaith, 1983) was administered at both time points and a modified List of Threatening Experiences (Brugha, Bebbington, Tennant, & Hurry, 1985) was administered mid-course. Results: By mid-course 9% of previously symptom-free students became depressed and 20% became anxious at a clinically significant level. Of those previously anxious or depressed 36% had recovered. After adjusting for pre-entry symptoms, financial difficulties made a significant independent contribution to depression and relationship difficulties independently predicted anxiety. Depression and financial difficulties mid-course predicted a decrease in exam performance from first to second year. Conclusions: This is the first study to confirm empirically that financial and other difficulties can increase British students' levels of anxiety and depression and that financial difficulties and depression can affect academic performance. However, university life may also have a beneficial effect for some students with pre-existing conditions. With widening participation in higher education, the results have important implications for educational and health policies.

Development of a passive, in situ, integrative sampler for hydrophilic organic contaminants in aquatic environments.

Abstract: Increasingly it is being realized that a holistic hazard assessment of complex environmental contaminant mixtures requires data on the concentrations of hydrophilic organic contaminants including new generation pesticides, pharmaceuticals, personal care products, and many chemicals associated with household, industrial, and agricultural wastes. To address this issue, we developed a passive in situ sampling device (the polar organic chemical integrative sampler [POCIS]) that integratively concentrates trace levels of complex mixtures of hydrophilic environmental contaminants, enables the determination of their time-weighted average water concentrations, and provides a method of estimating the potential exposure of aquatic organisms to the complex mixture of waterborne contaminants. Using a prototype sampler, linear uptake of selected herbicides and pharmaceuticals with log K(ow)s < 4.0 was observed for up to 56 d. Estimation of the ambient water concentrations of chemicals of interest is achieved by using appropriate uptake models and determination of POCIS sampling rates for appropriate exposure conditions. Use of POCIS in field validation studies targeting the herbicide diuron in the United Kingdom resulted in the detection of the chemical at estimated concentrations of 190 to 600 ng/L. These values are in agreement with reported levels found in traditional grab samples taken concurrently.

Interaction strengths in food webs: issues and opportunities

Abstract: Summary 1. Recent efforts to understand how the patterning of interaction strength affects both structure and dynamics in food webs have highlighted several obstacles to productive synthesis. Issues arise with respect to goals and driving questions, methods and approaches, and placing results in the context of broader ecological theory. 2. Much confusion stems from lack of clarity about whether the questions posed relate to community-level patterns or to species dynamics, and to what authors actually mean by the term ‘interaction strength’. Here, we describe the various ways in which this term has been applied and discuss the implications of loose terminology and definition for the development of this field. 3. Of particular concern is the clear gap between theoretical and empirical investigations of interaction strengths and food web dynamics. The ecological community urgently needs to explore new ways to estimate biologically reasonable model coefficients from empirical data, such as foraging rates, body size, metabolic rate, biomass distribution and other species traits. 4. Combining numerical and analytical modelling approaches should allow exploration of the conditions under which different interaction strengths metrics are interchangeable with regard to relative magnitude, system responses, and species identity. 5. Finally, the prime focus on predator‐prey links in much of the research to date on interaction strengths in food webs has meant that the potential significance of nontrophic interactions, such as competition, facilitation and biotic disturbance, has been largely ignored by the food web community. Such interactions may be important dynamically and should be routinely included in future food web research programmes.

Separate visual representations in the planning and control of action

Abstract: Evidence for a dichotomy between the planning of an action and its on-line control in humans is reviewed. This evidence suggests that planning and control each serve a specialized purpose utilizing distinct visual representations. Evidence from behavioral studies suggests that planning is influenced by a large array of visual and cognitive information, whereas control is influenced solely by the spatial characteristics of the target, including such things as its size, shape, orientation, and so forth. Evidence from brain imaging and neuropsychology suggests that planning and control are subserved by separate visual centers in the posterior parietal lobes, each constituting part of a larger network for planning and control. Planning appears to rely on phylogenetically newer regions in the inferior parietal lobe, along with the frontal lobes and basal ganglia, whereas control appears to rely on older regions in the superior parietal lobe, along with the cerebellum.

The broth in my brother's brothel: morpho-orthographic segmentation in visual word recognition.

Abstract: Much research suggests that words comprising more than one morpheme are represented in a “decomposed” manner in the visual word recognition system. In the research presented here, we investigate what information is used to segment a word into its morphemic constituents and, in particular, whether semantic information plays a role in that segmentation. Participants made visual lexical decisions to stem targets preceded by masked primes sharing (1) a semantically transparent morphological relationship with the target (e.g.,cleaner-CLEAN), (2) an apparent morphological relationship but no semantic relationship with the target (e.g.,corner-CORN), and (3) a nonmorphological form relationship with the target (e.g.,brothel-BROTH). Results showed significant and equivalent masked priming effects in cases in which primes and targets appeared to be morphologically related, and priming in these conditions could be distinguished from nonmorphological form priming. We argue that these findings suggest a level of representation at which apparently complex words are decomposed on the basis of their morpho-orthographic properties. Implications of these findings for computational models of reading are discussed.

Two are few and four are many: number effects in experimental oligopolies

Abstract: In this paper we investigate how the competitiveness of Cournot markets varies with the number of firms in an industry. We review previous Cournot experiments in the literature. Additionally, we conduct a new series of experiments studying oligopolies with two, three, four, and five firms in a unified frame. With two firms we find some collusion. Three-firm oligopolies tend to produce outputs at the Nash level. Markets with four or five firms are never collusive and typically settle at or above the Cournot outcome. Some of those markets are actually quite competitive with outputs close to the Walrasian outcome.

Trauma Films, Information Processing, and Intrusive Memory Development

Abstract: Three experiments indexed the effect of various concurrent tasks, while watching a traumatic film, on intrusive memory development. Hypotheses were based on the dual-representation theory of posttraumatic stress disorder (C. R. Brewin, T. Dalgleish, & S. Joseph, 1996). Nonclinical participants viewed a trauma film under various encoding conditions and recorded any spontaneous intrusive memories of the film over the following week in a diary. Changes in state dissociation, heart rate, and mood were also measured. As predicted, performing a visuospatial pattern tapping task at encoding significantly reduced the frequency of later intrusions, whereas a verbal distraction task increased them. Intrusive memories were largely unrelated to recall and recognition measures. Increases in dissociation and decreases in heart rate during the film were also associated with later intrusions.

Characterization of Bacillus Probiotics Available for Human Use

Abstract: Bacillus species (Bacillus cereus, Bacillus clausii, Bacillus pumilus) carried in five commercial probiotic products consisting of bacterial spores were characterized for potential attributes (colonization, immunostimulation, and antimicrobial activity) that could account for their claimed probiotic properties. Three B. cereus strains were shown to persist in the mouse gastrointestinal tract for up to 18 days postadministration, demonstrating that these organisms have some ability to colonize. Spores of one B. cereus strain were extremely sensitive to simulated gastric conditions and simulated intestinal fluids. Spores of all strains were immunogenic when they were given orally to mice, but the B. pumilus strain was found to generate particularly high anti-spore immunoglobulin G titers. Spores of B. pumilus and of a laboratory strain of B. subtilis were found to induce the proinflammatory cytokine interleukin-6 in a cultured macrophage cell line, and in vivo, spores of B. pumilus and B. subtilis induced the proinflammatory cytokine tumor necrosis factor alpha and the Th1 cytokine gamma interferon. The B. pumilus strain and one B. cereus strain (B. cereus var. vietnami) were found to produce a bacteriocin-like activity against other Bacillus species. The results that provided evidence of colonization, immunostimulation, and antimicrobial activity support the hypothesis that the organisms have a potential probiotic effect. However, the three B. cereus strains were also found to produce the Hbl and Nhe enterotoxins, which makes them unsafe for human use.

Geologic, geochemical, and geophysical consequences of plume involvement in the Emeishan flood-basalt province

Abstract: Prevolcanic kilometer-scale lithospheric doming in the Emeishan large igneous province, southwest China, allows us to evaluate the spatial and temporal consequences of uplift on the paleogeography, geology, geochemistry, and geophysics of the region. Systematic spatial variations are observed across the domal structure in the distribution and thickness of clastic and carbonate sediments, the extent of erosion, thickness, and chemistry of volcanic rocks, and the crust-mantle structure. These features, which are best explained by a mantle plume, may be used to track older plume sites in the geologic record.

Performance Pay and Teachers' Effort, Productivity and Grading Ethics

Abstract: Performance-related incentive pay for teachers is being introduced in many countries, but there is little evidence of its effects. This paper evaluates a rank-order tournament among teachers of English, Hebrew, and mathematics in Israel. Teachers were rewarded with cash bonuses for improving their students' performance on high-school matriculation exams. Two identification strategies were used to estimate the program effects, a regression discontinuity design and propensity score matching. The regression discontinuity method exploits both a natural experiment stemming from measurement error in the assignment variable and a sharp discontinuity in the assignment-to-treatment variable. The results suggest that performance incentives have a significant effect on directly affected students with some minor spillover effects on untreated subjects. The improvements appear to derive from changes in teaching methods, after-school teaching, and increased responsiveness to students' needs. No evidence found for teachers' manipulation of test scores. The program appears to have been more cost-effective than school-group cash bonuses or extra instruction time and is as effective as cash bonuses for students.

Process Transformation: Limitations to Radical Organizational Change within Public Service Organizations

Abstract: This paper draws on a study of the implementation of business process reengineering (BPR) in a UK National Health Service (NHS) hospital to examine the challenge of effecting a transformatory shift to a new form of process organization in a large and complex public service organization. The paper’s theoretical and empirical interests go beyond BPR by bringing together literatures about organizational transformation, new organizational forms and the new public management (NPM) in a novel way. Data reveal important limits to intended organizational transformation and develop findings about sedimented rather than transformational change and the limitations of radical top-down change strategies in professionalized public service organizations. Within the domain of public service organizations, the paper also advances a new argument about why intended moves to post-NPM forms may remain contained in scope.

WordGen: a tool for word selection and nonword generation in Dutch, English, German, and French.

Abstract: WordGen is an easy-to-use program that uses the CELEX and Lexique lexical databases for word selection and nonword generation in Dutch, English, German, and French. Items can be generated in these four languages, specifying any combination of seven linguistic constraints: number of letters, neighborhood size, frequency, summated position-nonspecific bigram frequency, minimum position-nonspecific bigram frequency, position-specific frequency of the initial and final bigram, and orthographic relatedness. The program also has a module to calculate the respective values of these variables for items that have already been constructed, either with the program or taken from earlier studies. Stimulus queries can be entered through WordGen’s graphical user interface or by means of batch files. WordGen is especially useful for (1) Dutch and German item generation, because no such stimulus-selection tool exists for these languages, (2) the generation of nonwords for all four languages, because our program has some important advantages over previous nonword generation approaches, and (3) psycholinguistic experiments on bilingualism, because the possibility of using the same tool for different languages increases the cross-linguistic comparability of the generated item lists. WordGen is free and available athttp://expsy.ugent.be/wordgen.htm.

Metabolic engineering of the mevalonate and non‐mevalonate isopentenyl diphosphate‐forming pathways for the production of health‐promoting isoprenoids in tomato

Abstract: The genetic manipulation of both the mevalonic acid (MVA) and methylerythritol-4-phosphate (MEP) pathways, leading to the formation of isopentenyl diphosphate (IPP), has been achieved in tomato using 3-hydroxymethylglutaryl CoA (hmgr-1) and 1-deoxy-d-xylulose-5-phosphate synthase (dxs) genes, respectively. Transgenic plants containing an additional hmgr-1 from Arabidopsis thaliana, under the control of the cauliflower mosaic virus (CaMV) 35S constitutive promoter, contained elevated phytosterols (up to 2.4-fold), but IPP-derived isoprenoids in the plastid were unaltered. Transgenic lines containing a bacterial dxs targeted to the plastid with the tomato dxs transit sequence resulted in an increased carotenoid content (1.6-fold), which was inherited in the next generation. Phytoene and beta-carotene exhibited the greatest increases (2.4- and 2.2-fold, respectively). Extra-plastidic isoprenoids were unaffected in these lines. These data are discussed with respect to the regulation, compartmentalization and manipulation of isoprenoid biosynthetic pathways and their relevance to plant biotechnology.

A protein kinase target of a PDK1 signalling pathway is involved in root hair growth in Arabidopsis

Abstract: Here we report on a lipid-signalling pathway in plants that is downstream of phosphatidic acid and involves the Arabidopsis protein kinase, AGC2-1, regulated by the 3′-phosphoinositide-dependent kinase-1 (AtPDK1). AGC2-1 specifically interacts with AtPDK1 through a conserved C-terminal hydrophobic motif that leads to its phosphorylation and activation, whereas inhibition of AtPDK1 expression by RNA interference abolishes AGC2-1 activity. Phosphatidic acid specifically binds to AtPDK1 and stimulates AGC2-1 in an AtPDK1-dependent manner. AtPDK1 is ubiquitously expressed in all plant tissues, whereas expression of AGC2-1 is abundant in fast-growing organs and dividing cells, and activated during re-entry of cells into the cell cycle after sugar starvation-induced G1-phase arrest. Plant hormones, auxin and cytokinin, synergistically activate the AtPDK1-regulated AGC2-1 kinase, indicative of a role in growth and cell division. Cellular localisation of GFP-AGC2-1 fusion protein is highly dynamic in root hairs and at some stages confined to root hair tips and to nuclei. The agc2-1 knockout mutation results in a reduction of root hair length, suggesting a role for AGC2-1 in root hair growth and development.

Conceptualizing the ICT Artifact: Toward Understanding the Role of ICT in National Development

Abstract: In development literature, information and communications technology (ICT) has been characterized as having the potential to enable national development. However, ICT has been conceptualized mostly as a monolithic and homogeneous entity. To a great extent, the ambiguous findings and diverse opinions on the role of ICT in national development can be attributed to this limited focus. In order to better understand the role ICT can play in national development, we believe that the ICT artifact needs to be examined in finer detail. We propose that ICT needs to be conceptualized in its many facets, perceptions, and in its manifold impact in societies. We use recent concepts from the IT literature to propose an integrative framework to study the role of ICT in development. Policymakers and donor agencies may find this framework useful in evaluating the potential impact of development interventions using ICT.

Demystifying disability: a review of the International Classification of Functioning, Disability and Health

Abstract: The paper describes and evaluates the theoretical underpinnings of the International Classification of Functioning, Disability and Health (ICF), and develops the proposition that its conceptual framework provides a coherent, if uneven, guide through the competing conceptions of disability. To date, however, there has been little evaluation of the theoretical efficacy of the ICF. In seeking to redress this, the paper develops the argument that the ICF fails to specify, in any detail, the content of some of its main claims about the nature of impairment and disability. This has the potential to limit its capacity to educate and influence users about the relational nature of disability. The paper develops the contention that three parts of the ICF require further conceptual clarification and development: (a) (re)defining the nature of impairment; (b) specifying the content of biopsychosocial theory; and (c) clarifying the meaning and implications of universalisation as a principle for guiding the development of disability policies.

Mass discrimination correction in multiple-collector plasma source mass spectrometry: an example using Cu and Zn isotopes

Abstract: Multiple-collector magnetic sector ICP-MS affords the possibility of applying instrumental mass discrimination corrections using a reference isotope ratio of an element (dopant) other than the analyte. Much attention has focused on the use of this approach for lead isotope analysis using a thallium dopant and the technique has also been applied to copper–zinc isotope analysis. The most successful applications of the doping approach have established empirical mass bias relationships between dopant and analyte isotope ratios but this often has to be done for single analytical sessions. Insufficient intra-session variation in mass discrimination often leads to poor constraints on these relationships. Moreover, with the Tl–Pb system there is some doubt over whether samples and standards exhibit the same relationship. Here we show that for the Cu–Zn system, two improvements on previous approaches lead to precise and accurate isotope ratios for unknowns. Firstly, addition of Sr to mixed Cu–Zn standard solutions generates extreme variation in mass bias so that empirical mass bias relationships between analyte and dopant are much better constrained. Secondly, we show that inadequate chemistry, specifically the inefficient removal of matrix Fe and Ti, seriously compromises the Cu–Zn isotope analysis of samples but that with clean chemistry, samples with complex matrices demonstrably yield similar mass discrimination relationships between Cu and Zn isotopes to standards. We also document previously unreported aspects of Cu–Zn isotope analysis: (1) that Cu–Zn mass bias relationships depend critically on the Cu/Zn ratio of the solution; (2) that for an introduction system with a desolvating membrane, the behaviour of standards is highly variable, perhaps due to variations in the oxidation state of Cu in the solution, and that this can be overcome by the passage of standards through the ion exchange procedure used to purify samples. Finally, we document chemical separation and mass spectrometric techniques that permit the isotopic analysis of order of magnitude smaller samples than previously achieved and report values for BCR-1 basalt standard of δ66Zn = 0.20 ± 0.09‰ (n = 12) and δ65Cu = 0.07 ± 0.08‰ (n = 6) at the 95% confidence level.

Grasping the meaning of words.

Abstract: Action affordances can be activated by non-target objects in the visual field as well as by word labels attached to target objects. These activations have been manifested in interference effects of distractors and words on actions. We examined whether affordances could be activated implicitly by words representing graspable objects that were either large (e.g., APPLE) or small (e.g., GRAPE) relative to the target. Subjects first read a word and then grasped a wooden block. Interference effects of the words arose in the early portions of the grasping movements. Specifically, early in the movement, reading a word representing a large object led to a larger grip aperture than reading a word representing a small object. This difference diminished as the hand approached the target, suggesting on-line correction of the semantic effect. The semantic effect and its on-line correction are discussed in the context of ecological theories of visual perception, the distinction between movement planning and control, and the proximity of language and motor planning systems in the human brain.

Millennial and orbital variations of El Niño/Southern Oscillation and high-latitude climate in the last glacial period

Abstract: The El Nino/Southern Oscillation (ENSO) phenomenon is believed to have operated continuously over the last glacial–interglacial cycle1. ENSO variability has been suggested to be linked to millennial-scale oscillations in North Atlantic climate during that time2,3, but the proposals disagree on whether increased frequency of El Nino events, the warm phase of ENSO, was linked to North Atlantic warm or cold periods. Here we present a high-resolution record of surface moisture, based on the degree of peat humification and the ratio of sedges to grass, from northern Queensland, Australia, covering the past 45,000 yr. We observe millennial-scale dry periods, indicating periods of frequent El Nino events (summer precipitation declines in El Nino years in northeastern Australia). We find that these dry periods are correlated to the Dansgaard–Oeschger events—millennial-scale warm events in the North Atlantic climate record—although no direct atmospheric connection from the North Atlantic to our site can be invoked. Additionally, we find climatic cycles at a semiprecessional timescale (∼11,900 yr). We suggest that climate variations in the tropical Pacific Ocean on millennial as well as orbital timescales, which determined precipitation in northeastern Australia, also exerted an influence on North Atlantic climate through atmospheric and oceanic teleconnections.

Bad Jobs in Britain : Nonstandard Employment and Job Quality

Abstract: The rapid growth in nonstandard forms of employment toward the end of the 20th century has fuelled claims about the spread of “bad jobs” within Anglo-American capitalism. Research from the United States indicates that such jobs have more bad characteristics than do permanent jobs after controlling for workers’ personal characteristics, family status, and occupation. We apply a version of the bad characteristics approach to British data and find that despite some institutional differences with the United States, (notably, in employer welfare provision), the British case also supports the hypothesis that nonstandard employment (part-time, temporary, and fixed term) increases workers’ exposure to bad job characteristics.

A zero-damage model for fission-track annealing in zircon

Abstract: A zircon fission track-annealing model is calculated on the basis of annealing experiments from the literature with induced tracks in α-decay event damage-free zircon samples. Empirically derived parallel and fanning equations for this “zero-damage” model yield an excellent fit to the data, with the fanning model providing slightly better statistical parameters. A comparison between annealing models with fanning iso-annealing lines but different α-decay event damage densities reveals that annealing temperatures and closure temperatures for the estimated partial annealing zone are highest for the zero-damage model. Compilations of existing geologic constraints on the zircon partial-annealing zone on one hand and the zircon closure temperature on the other show that these constraints do not or only partly overlap with curves of proposed models for the zircon partial-annealing zone and closure temperature. This finding is consistent with the fact that the annealing behavior of zircon from long-duration temperature evolutions is increasingly influenced by the accumulated α-decay event damage. Zircon samples of young age or low U content show a behavior closest to the predictions of the zero-damage model, and are in the predicted range of published models with low α-decay event damage density. For thermal events of more than 10 myr duration, however, constraints from field studies show marked differences from proposed partial-annealing zone boundaries of the zero- or low-damage models. The applicability of the zero-damage model is threefold. (1) It predicts correct closure temperatures in the case of very rapid cooling across the partial annealing zone where basically no α-decay event damage is accumulated. (2) It predicts an uppermost boundary for complete annealing of a mixture of zircon components of different age, as found in sedimentary samples, and in this case may be used as a thermometer. (3) It represents an important reference for the establishment of a more comprehensive model of zircon fission-track annealing that also includes the influence of α-decay event damage. For such a model, two different equations are discussed. However, additional detailed experimental and field data are needed for a more robust annealing model that includes the influence of α-decay event-damage annealing.

Developmental stress selectively affects the song control nucleus HVC in the zebra finch

Abstract: Songbirds sing complex songs as a result of evolution through sexual selection. The evolution of such sexually selected traits requires genetic control, as well as selection on their expression. Song is controlled by a discrete neural pathway in the brain, and song complexity has been shown to correlate with the volume of specific song control nuclei. As such, the development of these nuclei, in particular the high vocal centre (HVC), is thought to be the mechanism controlling signal expression indicating male quality. We tested the hypothesis that early developmental stress selectively affects adult HVC size, compared with other brain nuclei. We did this by raising cross-fostered zebra finches (Taeniopygia guttata) under stressed and controlled conditions and determining the effect on adult HVC size. Our results confirm the strong influence of environmental conditions, particularly on HVC development, and therefore on the expression of complex songs. The results also show that both environmental and genetic factors affect the development of several brain nuclei, highlighting the developmental plasticity of the songbird brain. In all, these results explain how the complex song repertoires of songbirds can evolve as honest indicators of male quality.