Showing papers by "Royal Holloway, University of London published in 2006"

Insights into social insects from the genome of the honeybee Apis mellifera

Abstract: Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.

The genome of the sea urchin Strongylocentrotus purpuratus.

Abstract: We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.

The primate cortico-cerebellar system: anatomy and function

Abstract: Evidence has been accumulating that the primate cerebellum contributes not only to motor control, but also to higher 'cognitive' function. However, there is no consensus about how the cerebellum processes such information. The answer to this puzzle can be found in the nature of cerebellar connections to areas of the cerebral cortex (particularly the prefrontal cortex) and in the uniformity of its intrinsic cellular organization, which implies uniformity in information processing regardless of the area of origin in the cerebral cortex. With this in mind, the relatively well-developed models of how the cerebellum processes information from the motor cortex might be extended to explain how it could also process information from the prefrontal cortex.

How general are positive relationships between plant population size, fitness and genetic variation?

Abstract: Summary 1Relationships between plant population size, fitness and within-population genetic diversity are fundamental for plant ecology, evolution and conservation. We conducted meta-analyses of studies published between 1987 and 2005 to test whether these relationships are generally positive, whether they are sensitive to methodological differences among studies, whether they differ between species of different life span, mating system or rarity and whether they depend on the size ranges of the studied populations. 2Mean correlations between population size, fitness and genetic variation were all significantly positive. The positive correlation between population size and female fitness tended to be stronger in field studies than in common garden studies, and the positive correlation between genetic variation and fitness was significantly stronger in DNA than in isoenzyme studies. 3The strength and direction of correlations between population size, fitness and genetic variation were independent of plant life span and the size range of the studied populations. The mean correlations tended to be stronger for the rare species than for common species. 4Expected heterozygosity, the number of alleles and the number or proportion of polymorphic loci significantly increased with population size, but the level of inbreeding FIS was independent of population size. The positive relationship between population size and the number of alleles and the number or proportion of polymorphic loci was stronger in self-incompatible than in self-compatible species. Furthermore, fitness and genetic variation were positively correlated in self-incompatible species, but independent of each other in self-compatible species. 5The close relationships between population size, genetic variation and fitness suggest that population size should always be taken into account in multipopulation studies of plant fitness or genetic variation. 6The observed generality of the positive relationships between population size, plant fitness and genetic diversity implies that the negative effects of habitat fragmentation on plant fitness and genetic variation are common. Moreover, the stronger positive associations observed in self-incompatible species and to some degree in rare species, suggest that these species are most prone to the negative effects of habitat fragmentation.

Automatic annotation of eukaryotic genes, pseudogenes and promoters

Abstract: The ENCODE gene prediction workshop (EGASP) has been organized to evaluate how well state-of-the-art automatic gene finding methods are able to reproduce the manual and experimental gene annotation of the human genome. We have used Softberry gene finding software to predict genes, pseudogenes and promoters in 44 selected ENCODE sequences representing approximately 1% (30 Mb) of the human genome. Predictions of gene finding programs were evaluated in terms of their ability to reproduce the ENCODE-HAVANA annotation. The Fgenesh++ gene prediction pipeline can identify 91% of coding nucleotides with a specificity of 90%. Our automatic pseudogene finder (PSF program) found 90% of the manually annotated pseudogenes and some new ones. The Fprom promoter prediction program identifies 80% of TATA promoters sequences with one false positive prediction per 2,000 base-pairs (bp) and 50% of TATA-less promoters with one false positive prediction per 650 bp. It can be used to identify transcription start sites upstream of annotated coding parts of genes found by gene prediction software. We review our software and underlying methods for identifying these three important structural and functional genome components and discuss the accuracy of predictions, recent advances and open problems in annotating genomic sequences. We have demonstrated that our methods can be effectively used for initial automatic annotation of the eukaryotic genome.

The Sorcerer's Apprentice Guide to Fault Attacks

Abstract: The effect of faults on electronic systems has been studied since the 1970s when it was noticed that radioactive particles caused errors in chips. This led to further research on the effect of charged particles on silicon, motivated by the aerospace industry, which was becoming concerned about the effect of faults in airborne electronic systems. Since then various mechanisms for fault creation and propagation have been discovered and researched. This paper covers the various methods that can be used to induce faults in semiconductors and exploit such errors maliciously. Several examples of attacks stemming from the exploiting of faults are explained. Finally a series of countermeasures to thwart these attacks are described.

Magma-maintained rift segmentation at continental rupture in the 2005 Afar dyking episode

Abstract: Occurring mainly over a week in September 2005, a 60-km-long section of the Afar depression in Ethiopia was torn apart by the injection of over 2 cubic kilometres of molten rock into the plate: an 8-metre-wide gap appeared at the surface. Satellite radar imagery reveals that a series of fissures opened, the rift shoulders rose, and the ground surface dropped above the molten rock. A similarly large rift took place in Krafla in Iceland 25 years ago, but in a series of events over a ten year period. The Afar incident suggests that magma intrusion into a dyke, rather than faulting of the crust, may be responsible for the segmentation of continental rifts. Seafloor spreading centres show a regular along-axis segmentation thought to be produced by a segmented magma supply in the passively upwelling mantle1,2. On the other hand, continental rifts are segmented by large offset normal faults, and many lack magmatism. It is unclear how, when and where the ubiquitous segmented melt zones are emplaced during the continental rupture process. Between 14 September and 4 October 2005, 163 earthquakes (magnitudes greater than 3.9) and a volcanic eruption occurred within the ∼60-km-long Dabbahu magmatic segment of the Afar rift, a nascent seafloor spreading centre in stretched continental lithosphere3,4. Here we present a three-dimensional deformation field for the Dabbahu rifting episode derived from satellite radar data, which shows that the entire segment ruptured, making it the largest to have occurred on land in the era of satellite geodesy. Simple elastic modelling shows that the magmatic segment opened by up to 8 m, yet seismic rupture can account for only 8 per cent of the observed deformation. Magma was injected along a dyke between depths of 2 and 9 km, corresponding to a total intrusion volume of ∼2.5 km3. Much of the magma appears to have originated from shallow chambers beneath Dabbahu and Gabho volcanoes at the northern end of the segment, where an explosive fissural eruption occurred on 26 September 2005. Although comparable in magnitude to the ten year (1975–84) Krafla events in Iceland5, seismic data suggest that most of the Dabbahu dyke intrusion occurred in less than a week. Thus, magma intrusion via dyking, rather than segmented normal faulting, maintains and probably initiated the along-axis segmentation along this sector of the Nubia–Arabia plate boundary.

A study of relationship between managers' leadership style and employees' job satisfaction

Abstract: Purpose – The purpose of this descriptive and cross‐sectional study is to explore the relationships between managers' leadership styles and employees' job satisfaction in Isfahan University Hospitals, Isfahan, Iran, 2004.Design/methodology/approach – The data were collected through the distribution of two questionnaires among the 814 employees, first line, middle and senior managers of these hospitals through a stratified random sampling.Findings – The dominant leadership style of managers was participative. The mean score of employee‐oriented dimension of leadership style in first line, middle and senior managers were 52, 54, and 54 (from 75 credit) respectively. The mean score of task‐oriented dimension of leadership style in first line, middle and senior managers were 68, 69, and 70 (from 100 credit) respectively. The mean score of employee's job satisfaction was 3.26±0.56 on a 6 scale (moderate satisfaction), 1.9, 26.1, 64.7, and 7.3 percent of hospital employees had respectively very low, low, modera...

Search for neutral MSSM Higgs bosons at LEP

Abstract: The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of “benchmark” models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter cosβ and, in some scenarios, on the masses of neutral Higgs bosons.

Peroxidase-dependent apoplastic oxidative burst in Arabidopsis required for pathogen resistance

Abstract: The oxidative burst is an early response to pathogen attack leading to the production of reactive oxygen species (ROS) including hydrogen peroxide. Two major mechanisms involving either NADPH oxidases or peroxidases that may exist singly or in combination in different plant species have been proposed for the generation of ROS. We identified an Arabidopsis thaliana azide-sensitive but diphenylene iodonium-insensitive apoplastic oxidative burst that generates H(2)O(2) in response to a Fusarium oxysporum cell-wall preparation. Transgenic Arabidopsis plants expressing an anti-sense cDNA encoding a type III peroxidase, French bean peroxidase type 1 (FBP1) exhibited an impaired oxidative burst and were more susceptible than wild-type plants to both fungal and bacterial pathogens. Transcriptional profiling and RT-PCR analysis showed that the anti-sense (FBP1) transgenic plants had reduced levels of specific peroxidase-encoding mRNAs, including mRNAs corresponding to Arabidopsis genes At3g49120 (AtPCb) and At3g49110 (AtPCa) that encode two class III peroxidases with a high degree of homology to FBP1. These data indicate that peroxidases play a significant role in generating H(2)O(2) during the Arabidopsis defense response and in conferring resistance to a wide range of pathogens.

Late survival of Neanderthals at the southernmost extreme of Europe

Abstract: Identifying the precise point when a species went extinct is probably impossible. You can never be sure that a fossil is the very last of its kind. The extinction of the Neanderthals in Europe is a case in point, but Finlayson et al. have gone further than anyone in their study of the Neanderthal occupation of Gorham's Cave in Gibraltar, showing that Neanderthals occupied this most southerly point of Europe as recently as 28,000 years ago, long after Neanderthals elsewhere in southwest Europe appear to have become extinct. The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia1. In Europe the extinction of the Neanderthals, firmly associated with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt2. Here we present data, based on a high-resolution record of human occupation from Gorham’s Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe.

The diversification of Paleozoic fire systems and fluctuations in atmospheric oxygen concentration.

Abstract: By comparing Silurian through end Permian [≈250 million years (Myr)] charcoal abundance with contemporaneous macroecological changes in vegetation and climate we aim to demonstrate that long-term variations in fire occurrence and fire system diversification are related to fluctuations in Late Paleozoic atmospheric oxygen concentration. Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (≈420 Myr) to the present. Its presence at any interval in the fossil record is already taken to constrain atmospheric oxygen within the range of 13% to 35% (the “fire window”). Herein, we observe that, as predicted, atmospheric oxygen levels rise from ≈13% in the Late Devonian to ≈30% in the Late Permian so, too, fires progressively occur in an increasing diversity of ecosystems. Sequentially, data of note include: the occurrence of charcoal in the Late Silurian/Early Devonian, indicating the burning of a diminutive, dominantly rhyniophytoid vegetation; an apparent paucity of charcoal in the Middle to Late Devonian that coincides with a predicted atmospheric oxygen low; and the subsequent diversification of fire systems throughout the remainder of the Late Paleozoic. First, fires become widespread during the Early Mississippian, they then become commonplace in mire systems in the Middle Mississippian; in the Pennsylvanian they are first recorded in upland settings and finally, based on coal petrology, become extremely important in many Permian mire settings. These trends conform well to changes in atmospheric oxygen concentration, as predicted by modeling, and indicate oxygen levels are a significant control on long-term fire occurrence.

The Intestinal Life Cycle of Bacillus subtilis and Close Relatives

Abstract: Bacillus subtilis is considered a soil organism for which endospore formation provides a means to ensure long-term survival in the environment. We have addressed here the question of what happens to a spore when ingested. Spores displaying on their surface a heterologous antigen, tetanus toxin fragment C (TTFC), were shown to generate anti-TTFC responses not to the antigen contained in the primary oral inoculum but to those displayed on spores that had germinated and then resporulated. We then used reverse transcription-PCR to determine expression of vegetative genes and sporulation-specific genes in the mouse gut following oral dosing with spores. Significant levels of germination and sporulation were documented. Using natural isolates of B. subtilis that could form biofilms, we showed that these strains could persist in the mouse gut for significantly longer than the laboratory strain. Moreover, these isolates could grow and sporulate anaerobically and exhibited a novel phenomenon of being able to form spores in almost half the time required for the laboratory isolate. This suggests that spores are not transient passengers of the gastrointestinal tract but have adapted to carry out their entire life cycle within this environment. This is the first report showing an intestinal life cycle of B. subtilis and suggests that other Bacillus species could also be members of the gut microflora.

Episodic fresh surface waters in the Eocene Arctic Ocean

Abstract: It has been suggested, on the basis of modern hydrology and fully coupled palaeoclimate simulations, that the warm greenhouse conditions that characterized the early Palaeogene period (55-45 Myr ago) probably induced an intensified hydrological cycle with precipitation exceeding evaporation at high latitudes. Little field evidence, however, has been available to constrain oceanic conditions in the Arctic during this period. Here we analyse Palaeogene sediments obtained during the Arctic Coring Expedition, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch (approximately 50 Myr ago). The Azolla and accompanying abundant freshwater organic and siliceous microfossils indicate an episodic freshening of Arctic surface waters during an approximately 800,000-year interval. The abundant remains of Azolla that characterize basal middle Eocene marine deposits of all Nordic seas probably represent transported assemblages resulting from freshwater spills from the Arctic Ocean that reached as far south as the North Sea. The termination of the Azolla phase in the Arctic coincides with a local sea surface temperature rise from approximately 10 degrees C to 13 degrees C, pointing to simultaneous increases in salt and heat supply owing to the influx of waters from adjacent oceans. We suggest that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas.

GridPP: development of the UK computing Grid for particle physics

Abstract: The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the international effort towards computing for the Large Hadron Collider. The project, funded by the UK Particle Physics and Astronomy Research Council (PPARC), began in September 2001 and completed its first phase 3 years later. GridPP is a collaboration of approximately 100 researchers in 19 UK university particle physics groups, the Council for the Central Laboratory of the Research Councils and CERN, reflecting the strategic importance of the project. In collaboration with other European and US efforts, the first phase of the project demonstrated the feasibility of developing, deploying and operating a Grid-based computing system to meet the UK needs of the Large Hadron Collider experiments. This note describes the work undertaken to achieve this goal.

The impact of organizational culture on the successful implementation of total quality management

Abstract: Purpose – The purpose of the paper is to determine the impact of cultural values on the success of TQM implementation in Isfahan University Hospitals (IUHs), Iran, 2004.Design/methodology/approach – In this paper survey questionnaires were used to elicit responses from hospital managers and employees. Data collected included the characteristics of organizational culture in IUHs and the degree of TQM success and its implementation problems in these hospitals.Findings – The paper finds that TQM success in IUHs was medium. Implementation of TQM was very low, low, medium and highly successful respectively in 16.7, 16.7, 58.3 and 8.3 percent of hospitals. TQM had the most effect on process management, focus on customers and leadership and management and less effect on focus on suppliers, performance results, strategic planning and focus on material resources. Human resource problems, performance appraisal and strategic problems were the most important obstacles to TQM success respectively. A total of 75 and 25...

Reexamining the word length effect in visual word recognition: New evidence from the English Lexicon Project

Abstract: In the present study, we reexamined the effect of word length (number of letters in a word) on lexical decision. Using the English Lexicon Project, which is based on a large data set of over 40,481 words (Balota et al., 2002), we performed simultaneous multiple regression analyses on a selection of 33,006 English words (ranging from 3 to 13 letters in length). Our analyses revealed an unexpected pattern of results taking the form of a U-shaped curve. The effect of number of letters was facilitatory for words of 3–5 letters, null for words of 5–8 letters, and inhibitory for words of 8–13 letters. We also showed that printed frequency, number of syllables, and number of orthographic neighbors all made independent contributions. The length effects were replicated in a new analysis of a subset of 3,833 monomorphemic nouns (ranging from 3 to 10 letters), and also in another analysis based on 12,987 bisyllabic items (ranging from 3 to 9 letters). These effects were independent of printed frequency, number of syllables, and number of orthographic neighbors. Furthermore, we also observed robust linear inhibitory effects of number of syllables. Implications for models of visual word recognition are discussed.

Altruism through beard chromodynamics

Abstract: The evolution of altruism, especially as directed to non-kin, is an enigma of evolutionary biology. Explanations would come easier, however, if altruists were readily recognized. Arguably the simplest recognition system is a conspicuous, heritable tag. A green beard would do it. A few examples of the ‘green beard effect’ have been reported in human interactions, though beards per se and greenness tend not to feature. A problem with this explanation is the improbability of one gene encoding all three functions (altruism, tag and recognition). Based on modelling, Jansen and van Baalen identify a further problem with this theory: even if green beard genes can be selectively advantageous, altruism is unstable under previous assumptions. But, they add, the evolution of cooperation using a recognition mechanism may be more likely if many beard colours coexist. Resolving the enigma of the evolution of altruism is helped along by models showing that the coexistence of many tags makes the evolution of cooperation using a recognition mechanism more likely. The evolution of altruism, a behaviour that benefits others at one's own fitness expense, poses a darwinian paradox. The paradox is resolved if many interactions are with related individuals so that the benefits of altruism are reaped by copies of the altruistic gene in other individuals1, a mechanism called kin selection2. However, recognition of altruists could provide an alternative route towards the evolution of altruism1,3,4,5. Arguably the simplest recognition system is a conspicuous, heritable tag, such as a green beard1,3. Despite the fact that such genes have been reported6,7,8, the ‘green beard effect’3 has often been dismissed because it is unlikely that a single gene can code for altruism and a recognizable tag1,3,9. Here we model the green beard effect and find that if recognition and altruism are always inherited together, the dynamics are highly unstable, leading to the loss of altruism. In contrast, if the effect is caused by loosely coupled separate genes, altruism is facilitated through beard chromodynamics in which many beard colours co-occur. This allows altruism to persist even in weakly structured populations and implies that the green beard effect, in the form of a fluid association of altruistic traits with a recognition tag, can be much more prevalent than hitherto assumed.

A place of sense: a kinaesthetic ethnography of cyclists on Mont Ventoux

Abstract: In this paper I explore the notion that our movements in and through a place define our engagement with it and help to constitute it as a place. Concepts and concomitant interpretations of place as a ‘situated’ and contemplative experience have to date received much cultural geographical attention. In increasingly mobile societies, however, I argue that mobility should be central to the ways in which we conceptualise and understand the character and meanings of different spaces and places. Although geographical exploration has begun concerning the politics and power relations of the mobile subject, little attention has yet been paid to the experiences and spatialities generative of the body-subject in mobility. Whilst acknowledging the importance of representations in directing action, I strategically emphasise and explore the notion that we create meaning and belong in a place according to how we are in a place. Drawing upon ethnographic work with racing and touring cyclists in the United Kingdom and France, I consider how the conjoining of the person and bike and the resulting embodied rhythms and kinaesthetic sensations of the movement of cycling are constitutive of the character and meanings of particular places. Ultimately, in this paper I point to an understanding of the kinaesthetic and sensuous experiences of the hybrid subject – object (in this instance ‘the cyclist’) as fundamental in rethinking how people live, feel, and ultimately create meaningful spatial relations.

Lifestyle meets market: Bohemian entrepreneurs in creative industries

Abstract: By linking lifestyle studies with creative industries research, this article opens a new perspective on creativity and innovation management. We argue that artists in the creative industries have to bridge the gap between artistic work and the economic need for self-management, and that a bohemian lifestyle essentially supports them in doing so. The bohemian lifestyle, which is characterized by a devotion to art for art’s sake, is an essential source for work motivation of artists and an increasing number of other creative workers. The article draws upon an empirical study into artistic work and employment in German theatres. Enacting a bohemian lifestyle enables actors as ‘bohemian entrepreneurs’ to integrate intensive selfmanagement and self-marketing as well as subordination of private life to work into their artistic work life. Analysing the link between lifestyle and creative work is crucial for understanding the way in which creative workers become artists and, at the same time, entrepreneurs of their creative talent.

The Evolution of Prefrontal Inputs to the Cortico-pontine System: Diffusion Imaging Evidence from Macaque Monkeys and Humans

Abstract: The cortico-ponto-cerebellar system is one of the largest projection systems in the primate brain, but in the human brain the nature of the information processing in this system remains elusive. Determining the areas of the cerebral cortex which contribute projections to this system will allow us to better understand information processing within it. Information from the cerebral cortex is conveyed to the cerebellum by topographically arranged fibres in the cerebral peduncle - an important fibre system in which all cortical outputs spatially converge on their way to the cerebellum via the pontine nuclei. Little is known of their anatomical organization in the human brain. New in vivo diffusion imaging and probabilistic tractography methods now offer a way in which input tracts in the cerebral peduncle can be characterized in detail. Here we use these methods to contrast their organization in humans and macaque monkeys. We confirm the dominant contribution of the cortical motor areas to the macaque monkey cerebral peduncle. However, we also present novel anatomical evidence for a relatively large prefrontal contribution to the human cortico-ponto-cerebellar system in the cerebral peduncle. These findings suggest the selective evolution of prefrontal inputs to the human cortico-ponto-cerebellar system.

Quality of life in age-related macular degeneration: a review of the literature

Abstract: The Age-related Macular Degeneration Alliance International commissioned a review of the literature on quality of life (QoL) in macular degeneration (MD) with a view to increasing awareness of MD, reducing its impact and improving services for people with MD worldwide. A systematic review was conducted using electronic databases, conference proceedings and key journal hand search checks. The resulting 'White Paper' was posted on the AMD Alliance website and is reproduced here. MD is a chronic, largely untreatable eye condition which leads to loss of central vision needed for tasks such as reading, watching TV, driving, recognising faces. It is the most common cause of blindness in the Western world. Shock of diagnosis, coupled with lack of information and support are a common experience. Incidence of depression is twice that found in the community-dwelling elderly, fuelled by functional decline and loss of leisure activities. Some people feel suicidal. MD threatens independence, especially when comorbidity exacerbates functional limitations. Rehabilitation, including low vision aid (LVA) provision and training, peer support and education, can improve functional and psychological outcomes but many people do not receive services likely to benefit them. Medical treatments, suitable for only a small minority of people with MD, can improve vision but most limit progress of MD, at least for a time, rather than cure. The White Paper considers difficulties associated with inappropriate use of health status measures and misinterpretation of utility values as QoL measures: evidence suggests they have poor validity in MD. There is considerable evidence for the major damage done to QoL by MD which is underestimated by health status and utility measures. Medical treatments are limited to a small proportion of people. However, much can be done to improve QoL by early diagnosis of MD with good communication of prognosis and continuing support. Support could include provision of LVAs, peer support, education and effective help in adjusting to MD. It is vital that appropriate measures of visual function and QoL be used in building a sound evidence base for the effectiveness of rehabilitation and treatment.

Hunt warm, rest cool: bioenergetic strategy underlying diel vertical migration of a benthic shark

Abstract: Summary 1. Diel vertical migration (DVM) is a widespread phenomenon among marine and freshwater organisms and many studies with various taxa have sought to understand its adaptive significance. Among crustacean zooplankton and juveniles of some fish species DVM is accepted widely as an antipredator behaviour, but little is known about its adaptive value for relatively large-bodied, adult predatory fish such as sharks. Moreover, the majority of studies have focused on pelagic forms, which raises the question of whether DVM occurs in bottom-living predators. 2. To investigate DVM in benthic predatory fish in the marine environment and to determine why it might occur we tracked movements of adult male dogfish ( Scyliorhinus canicula ) by short- and long-term acoustic and archival telemetry. Movement studies were complemented with measurements of prey abundance and availability and thermal habitat within home ranges. A thermal choice experiment and energy budget modelling was used to investigate trade-offs between foraging and thermal habitat selection. 3. Male dogfish undertook normal DVM (nocturnal ascent) within relatively small home ranges ( ∼ 100 × 100 m) comprising along-bottom movements up submarine slopes from deeper, colder waters occupied during the day into warmer, shallow prey-rich areas above the thermocline at night. Few daytime vertical movements occurred. Levels of activity were higher during the night above the thermocline compared to below it during the day indicating they foraged in warm water and rested in colder depths. 4. A thermal choice experiment using environmentally realistic temperatures supported the field observation that dogfish positively avoided warmer water even when it was associated with greater food availability. Males in laboratory aquaria moved into warm water from a cooler refuge only to obtain food, and after food consumption they preferred to rest and digest in cooler water. 5. Modelling of energy budgets under different realistic thermal-choice scenarios indicated dogfish adopting a ‘hunt warm − rest cool’ strategy could lower daily energy costs by just over 4%. Our results provide the first clear evidence that are consistent with the hypothesis that a benthic marine-fish predator utilizes DVM as an energy conservation strategy that increases bioenergetic efficiency.

Concurrent correlates and predictors of reading and spelling achievement in deaf and hearing school children.

Abstract: Seven- and eight-year-old deaf children and hearing children of equivalent reading age were presented with a number of tasks designed to assess reading, spelling, productive vocabulary, speechreading, phonological awareness, short-term memory, and nonverbal intelligence. The two groups were compared for similarities and differences in the levels of performance and in the predictors of literacy. Multiple regressions showed that both productive vocabulary and speechreading were significant predictors of reading for the deaf children after hearing loss and nonverbal intelligence had been accounted for. However, spelling ability was not associated with any of the other measures apart from reading. For hearing children, age was the main determinant of reading and spelling ability (due to selection criterion). Possible explanations for the role of speechreading and productive vocabulary in deaf children’s reading and the differences between the correlates of literacy for deaf and hearing children are discussed.