Showing papers by "University of Greenwich published in 2004"

Enterprise resource planning: An integrative review

Abstract: Enterprise resource planning (ERP) system solutions are currently in high demand by both manufacturing and service organisations because they provide a tightly integrated solution to an organisation's information system needs. During the last decade, ERP systems have received a significant amount of attention from researchers and practitioners from a variety of functional disciplines. In this paper, a comprehensive review of the research literature (1990‐2003) concerning ERP systems is presented. The literature is further classified and the major outcomes of each study are addressed and analysed. Following a comprehensive review of the literature, proposals for future research are formulated to identify topics where fruitful opportunities exist.

Culture-Level Dimensions of Social Axioms and Their Correlates across 41 Cultures

Abstract: Leung and colleagues have revealed a five-dimensional structure of social axioms across individuals from five cultural groups. The present research was designed to reveal the culture level factor structure of social axioms and its correlates across 41 nations. An ecological factor analysis on the 60 items of the Social Axioms Survey extracted two factors: Dynamic Externality correlates with value measures tapping collectivism, hierarchy, and conservatism and with national indices indicative of lower social development. Societal Cynicism is less strongly and broadly correlated with previous values measures or other national indices and seems to define a novel cultural syndrome. Its national correlates suggest that it taps the cognitive component of a cultural constellation labeled maleficence, a cultural syndrome associated with a general mistrust of social systems and other people. Discussion focused on the meaning of these national level factors of beliefs and on their relationships with individual level factors of belief derived from the same data set.

Infant vitamin D supplementation and allergic conditions in adulthood: Northern Finland Birth Cohort 1966

Abstract: Allergen-induced secretion of Th2-type cytokines and IgE production have recently been reported to be increased in mice treated with 1,25(OH)(2)D, the active form of vitamin D. Our objective was to investigate whether vitamin D supplementation in infancy is associated with the risk of atopy, allergic rhinitis, and asthma. The Northern Finland Birth Cohort consists of all individuals in the two most northern provinces of Finland who were due to be born in 1966. Data on vitamin D supplementation during the first year of life was obtained in 1967. Current asthma and allergic rhinitis were reported at age 31 years (n = 7,648), and atopy determined by skin-prick test in a sub-sample still living in northern Finland or the Helsinki area (n = 5,007). The prevalence of atopy and allergic rhinitis at age 31 years was higher in participants who had received vitamin D supplementation regularly during the first year compared to others (OR 1.46, 95%CI 1.4-2.0, and OR 1.66, 95%CI 1.1-1.6, respectively). A similar association was observed for asthma (OR 1.35, 95%CI 0.99-1.8). These associations persisted after adjustment for a wide range of behavioral and social factors (adjusted: OR 1.33 for all, P = 0.01 for atopy, P = 0.001 for allergic rhinitis, and P = 0.08 for asthma). We observed an association between vitamin D supplementation in infancy and an increased risk of atopy and allergic rhinitis later in life. Further study is required to determine whether these observations reflect long-term effects on immune regulation or differences in unmeasured determinants of vitamin D supplementation.

Cassava mosaic geminiviruses in Africa.

Abstract: Cassava mosaic disease (CMD) caused by cassava mosaic geminiviruses (CMGs) (Geminiviridae:Begomovirus) is undoubtedly the most important constraint to the production of cassava in Africa at the outset of the 21st century. Although the disease was recorded for the first time in the latter part of the 19th century, for much of the intervening period it has been relatively benign in most of the areas where it occurs and has generally been considered to be of minor economic significance. Towards the end of the 20th century, however, the inherent dynamism of the causal viruses was demonstrated, as a recombinant hybrid of the two principal species was identified, initially from Uganda, and shown to be associated with an unusually severe and rapidly spreading epidemic of CMD. Subsequent spread throughout East and Central Africa, the consequent devastation of production of the cassava crop, a key staple in much of this region, and the observation of similar recombination events elsewhere, has once again demonstrated the inherent danger posed to man by the capacity of these viruses to adapt to their environment and optimally exploit their relationships with the whitefly vector, plant host and human cultivator. In this review of cassava mosaic geminiviruses in Africa, we examine each of these relationships, and highlight the ways in which the CMGs have exploited them to their own advantage.

Epidemiology of insect-transmitted plant viruses: modelling disease dynamics and control interventions.

Abstract: Plant viruses are an important constraint to crop production world-wide. Rarely have plant virologists, vector entomologists and crop specialists worked together in search of sustainable management practices for viral diseases. Historically, modelling approaches have been vector-based dealing with empirical forecasting systems or simulation of vector population dynamics. More recently, epidemiological models, such as those used in human/animal epidemiology, have been introduced in an attempt to characterize and analyse the population ecology of viral diseases. The theoretical bases for these models and their use in evaluating control strategies in terms of the interactions between host, virus and vector are considered here. Vector activity and behaviour, especially in relation to virus transmission, are important determinants of the rate and extent of epidemic development. The applicability and flexibility of these models are illustrated by reference to specific case studies, including the increasing importance of whitefly-transmitted viruses. Some outstanding research and methodological issues are considered.

Planning Machine Maintenance in Two-machine Shop Scheduling

Abstract: We consider the two-machine open shop and two-machine flow shop scheduling problems in which each machine has to be maintained exactly once during the planning period, and the duration of each of these intervals depends on its start time. The objective is to minimize the maximum completion time of all activities to be scheduled. We resolve complexity and approximability issues of these problems. The open shop problem is shown to be polynomially solvable for quite general functions defining the length of the maintenance intervals. By contrast, the flow shop problem is proved binary NP-hard and pseudopolynomially solvable by dynamic programming. We also present a fully polynomial approximation scheme and a fast 3/2-approximation algorithm.

Midlatitude shelf seas in the Cenomanian‐Turonian greenhouse world: Temperature evolution and North Atlantic circulation

Abstract: [1] An 8 million year record of subtropical and midlatitude shelf-sea temperatures, derived from oxygen isotopes of well-preserved brachiopods from a variety of European sections, demonstrates a long-term Cenomanian temperature rise (16–20°C, midlatitudes) that reached its maximum early in the late Turonian (23°C, midlatitudes). Superimposed on the long-term trend, shelf-sea temperatures vary at shorter timescales in relation to global carbon cycle perturbations. In the mid-Cenomanian and the late Turonian, two minor shelf-sea cooling events (2–3°C) coincide with carbon cycle perturbations and times of high-amplitude sea level falls. Although this evidence supports the hypothesis of potential glacioeustatic effects on Cretaceous sea level, the occurrence of minimum shelf-sea temperatures within transgressive beds argues for regional changes in shelf-sea circulation as the most plausible mechanism. The major carbon cycle event in the latest Cenomanian (oceanic anoxic event 2) is accompanied by a substantial increase in shelf-sea temperatures (4–5°C) that occurred ∼150 kyr after the commencement of the δ13C excursion and is related to the spread of oceanic conditions in western European shelf-sea basins. Our oxygen isotope record and published δ18O data of pristinely preserved foraminifera allow the consideration of North Atlantic surface water properties in the Cenomanian along a transect from the tropics to the midlatitudes. On the basis of fossil-derived δ18O, estimated δw ranges, and modeled salinities, temperature-salinity-density ranges were estimated for tropical, subtropical, and midlatitude surface waters. Accordingly, the Cenomanian temperate shelf-seas waters have potentially the highest surface water density and could have contributed to North Atlantic intermediate to deep waters in the preopening stage of the equatorial Atlantic gateway.

Utilization of research findings by graduate nurses and midwives

Abstract: Background. There is mounting pressure on nurses and midwives in the United Kingdom to use research findings to inform their practice. However, many still find research difficult to understand and are poorly prepared by education to make use of it. Hence, there is a pressing need to evaluate the research education included in nursing and midwifery curricula. Aim. This paper reports a study assessing the impact of research education on the attitudes towards research and use of research findings in practice by graduate nurses and midwives. Method. A cross-sectional survey using a self-completed postal questionnaire was conducted with a sample of 340 nurse and midwife graduates in the South East of England. Findings. A response rate of 51% was obtained. A large number of respondents stated that their critical appraisal (96%) and search skills (87%) had improved following graduation and they reported using research findings in practice (16·8% all the time, 50·5% frequently and 32·6% sometimes). Furthermore, the majority expressed positive attitudes towards research and these were related to the research education received. However, a significant number reported finding statistics difficult to understand, lack of time to read research and limited access to research findings at their place of work. Also, a number of respondents would still like more help with searching the literature, implementing research findings in practice and developing their critical appraisal skills further. Conclusion. It is crucial that some of the major barriers to research utilization are addressed at both individual and organizational levels if evidence-based care is to become a reality. Also, health service managers should consider a number of strategies suggested by respondents to increase the use of research findings in clinical settings.

The effect of Coca-Cola and fruit juices on the surface hardness of glass-ionomers and 'compomers'.

Abstract: The interaction of tooth-coloured dental restorative materials (a conventional glass-ionomer, two resin-modified glass-ionomers and two compomers) with acidic beverages has been studied with the aim of investigating how long-term contact affects solution pH and specimen surface hardness. For each material (ChemFil Superior, ChemFlex, Vitremer Core Build-Up/Restorative, Fuji II LC, Dyract AP and F2000) disc-shaped specimens were prepared and stored in sets of six in the following storage media: 0.9% NaCl (control), Coca-Cola, apple juice and orange juice. After time intervals of 1 day, 1 week, 1 month, 3 months, 4 months, 6 months and 1 year, solution pH and Vickers Hardness Number were determined for each individual specimen. Differences were analysed by anova followed by Student-Newman-Keuls post hoc analysis. All materials were found to reduce the pH of the 0.9% NaCl, but to increase the pH of the acidic beverages. The conventional glass-ionomers dissolved completely in apple juice and orange juice, but survived in Coca-Cola, albeit with a significantly reduced hardness after 1 year. The other materials survived in apple juice and orange juice, but showed greater reductions in surface hardness in these beverages than in Coca-Cola. Fruit juices were thus shown to pose a greater erosive threat to tooth coloured materials than Coca-Cola, a finding which is similar to those concerning dentine and enamel towards these drinks.

Identification and mapping of AFLP markers linked to peanut (Arachis hypogaea L.) resistance to the aphid vector of groundnut rosette disease

Abstract: Groundnut rosette disease is the most destructive viral disease of peanut in Africa and can cause serious yield losses under favourable conditions. The development of disease-resistant cultivars is the most effective control strategy. Resistance to the aphid vector, Aphis craccivora, was identified in the breeding line ICG 12991 and is controlled by a single recessive gene. Bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) analysis were employed to identify DNA markers linked to aphid resistance and for the development of a partial genetic linkage map. A F2:3 population was developed from a cross using the aphid-resistant parent ICG 12991. Genotyping was carried out in the F2 generation and phenotyping in the F3 generation. Results were used to assign individual F2 lines as homozygous-resistant, homozygous-susceptible or segregating. A total of 308 AFLP (20 EcoRI+3/MseI+3, 144 MluI+3/MseI+3 and 144 PstI+3/MseI+3) primer combinations were used to identify markers associated with aphid resistance in the F2:3 population. Twenty putative markers were identified, of which 12 mapped to five linkage groups covering a map distance of 139.4 cM. A single recessive gene was mapped on linkage group 1, 3.9 cM from a marker originating from the susceptible parent, that explained 76.1% of the phenotypic variation for aphid resistance. This study represents the first report on the identification of molecular markers closely linked to aphid resistance to groundnut rosette disease and the construction of the first partial genetic linkage map for cultivated peanut.

An aerial netting study of insects migrating at high altitude over England.

Abstract: Day and night sampling of windborne arthropods at a height of 200 m above ground was undertaken at Cardington, Bedfordshire, UK, during July 1999, 2000 and 2002, using a net supported by a tethered balloon. The results from this study are compared with those from the classic aerial sampling programmes carried out by Hardy, Freeman and colleagues over the UK and North Sea in the 1930s. In the present study, aerial netting was undertaken at night as well as daytime, and so the diel periodicity of migration could be investigated, and comparisons made with the results from Lewis and Taylor’s extensive survey of flight periodicity near ground level. In some taxa with day-time emigration, quite large populations could continue in high-altitude flight after dark, perhaps to a previously underrated extent, and this would greatly increase their potential migratory range. Any trend towards increases in night temperatures, associated with global warming, would facilitate movements of this type in the UK. Observations on the windborne migration of a variety of species, particularly those of economic significance or of radar-detectable size, are briefly discussed.

A Middle Jurassic dinosaur trackway site from Oxfordshire, UK

Abstract: The Middle Jurassic (Bathonian) Ardley trackway site in Oxfordshire, UK is described in detail. The track site is extensive, containing over 40 more-or-less continuous theropod and sauropod trackways preserved together on a single bedding plane with some trackways up to 180 m in length. The trackways display reasonable preservation, with claw marks discernible. Sauropod trackways are by far the most abundant and are representative of taxa that exhibit both narrow and wide-gauge styles of locomotion. Theropod trackways are represented by large tridactyl prints and claw impressions that display exceptionally low pace angulation values during their walking phase. One theropod trackway is unique in that it reveals a gait transition associated with a temporary increase of speed. These dinosaurs were walking over a lime-mud firmground to hardground that was emergent, or locally very shallowly submerged. GPS (Global Positioning Satellite) data reveal that the tracks, preserved during a short time interval, trend in a north-easterly direction. Multi-herding behaviour is suggested for the sauropods of differing size. The discovery of this site adds significantly to our knowledge of the taxonomic composition of Middle Jurassic ecosystems. Evidence concerning locomotor styles employed by saurischian dinosaurs, footprint identification, potential trackmaker, social interactions and observations concerning estimates of Middle Jurassic faunal diversity, as well as aspects of dinosaur locomotor evolution are discussed.

HRD and the challenges of assessing learning in the workplace

Abstract: Increasingly the different ways in which learning can be conceptualised alongside debates within the field of human resource development (HRD) regarding its nature and purpose, potentially lead to confusion regarding how learning is to be assessed in the workplace. This article identifies some of the complexities associated with assessing learning in today's workplace and presents empirical findings suggesting that different aspects of an organisation's training and development system are likely to differentially determine the extent to which either formal or informal learning is assessed. Explanations as to why this may be the case are put forward.

Mothers and child care: policies, values and theories

Abstract: Government expansion of child care services is based on the assumption that both parents are employed (the adult worker model) and make cost-benefit calculations in choosing child care (the rational economic choice model). This paper addresses this assumption, based on research examining mothers' assessments of appropriate child care. These assessments involve complex moral and emotional decisions around their own and their children's needs, and differ between social groups. On this basis, we conclude that the assumptions underlying current child care expansion policy are inadequate, and that the mere expansion of services is not enough.

Gypsy Travellers and Education: Changing Needs and Changing Perceptions

Abstract: This article explores Gypsy Travellers’ changing views on their children's education. It highlights the positive means some schools use to encourage greater involvement of Gypsy Traveller parents. It argues that current educational policy needs to be re-developed to incorporate more effective and affirmative responses to interrupted and nomadic learning. It draws heavily on interviews with Gypsy Traveller families in an effort to give ‘voice’ to an under-represented community.

Three dimensional temperature measurement of combustion flames using a single monochromatic CCD camera

Abstract: This paper presents an imaging-based instrumentation system for three-dimensional (3-D) temperature measurement of a combustion flame. A combination of image-processing techniques and two-color radiation thermometry is used to first reconstruct band-limited grayscale representations of the flame and then to determine its temperature distribution. The reconstruction process assumes rotational symmetry in the structure of the flame. A series of experiments has been conducted on a laboratory-scale combustion rig to evaluate the performance of the system. The results obtained demonstrate the capability of the system to determine flame temperature on a 3-D basis.

Adding value: investigating the discourse of professionalism adopted by vocational teachers in further education colleges

Abstract: This article is set in the broad context of debates about the nature of professionalism, in particular the professionalism of teachers in the post‐compulsory sector. The focus is on teachers of vocational subjects in further education (FE) in England and on their perceptions of their role and work in preparing their learners for employment. In the context of recent changes to the vocational education curriculum, we sought to ascertain how well they believed they were able to do this work and what constraints and opportunities they experienced in the college. Semi‐structured interviews were carried out with 22 respondents, drawn from a range of five colleges. All were teachers of either engineering, health and social care, or hospitality and catering. Data analysis involved the identification of key narratives that were used by the respondents to support a discourse (Parker, 1990) of professionalism in vocational teaching. Four frequently occurring narratives are identified, including the need to ‘add valu...

Raspite and studtite: Raman spectra of two unique minerals

Abstract: The Raman and IR spectra of monoclinic naturally occurring raspite, α-PbWO4 (space group P21/a) were measured; it is irreversibly transformed to the tetragonal stolzite, β-PbWO4, by heating to 450°C, and this process was followed by Raman spectroscopy. Assignments of fundamental modes are proposed. New data are also presented on single crystals of stolzite (space group I41/a), and it is shown that raspite and stolzite can easily be distinguished by their Raman spectra. We also present Raman and IR spectroscopic data on natural and synthetic studtite, UO4·4H2O, and its synthetic dehydration product metastudtite, UO4·2H2O, the only two naturally occurring peroxide-containing minerals, and on partially deuterated synthetic forms of these materials. Assignments of fundamental modes are proposed and both TGA and DSC data are presented for studtite. Copyright © 2004 John Wiley & Sons, Ltd.

Dual begomovirus infections and high Bemisia tabaci populations: two factors driving the spread of a cassava mosaic disease pandemic

Abstract: A cassava mosaic disease (CMD) pandemic currently affects much of East and Central Africa. To understand the factors driving the pandemic’s continued spread, complementary data sets were collected from cassava plots, planted with healthy cuttings, at eight sites along a north–south transect in southern Uganda, through the pandemic’s leading edge. Data were collected on virus incidence, symptom severity, populations of the whitefly vector, Bemisia tabaci , their infectivity and ability to transmit different viruses. In 1996, 6 months after planting, CMD incidences were highest at sites 1 and 2, then decreased progressively until site 6, and remained low at sites 7 and 8. The largest B. tabaci populations also occurred at northernmost sites, 1–3. In 1997, CMD incidence increased significantly at sites 5–8 and this was associated with significant increases in the B. tabaci populations. The pandemic’s spread was also associated with significant increases in the percentage of dual infections of East African cassava mosaic virus-Uganda and African cassava mosaic virus, which caused the severest symptoms and the greatest reduction in leaf area. Whitefly adults collected from within the pandemic area were infective, whereas those collected ahead of the pandemic were not. The transmission rate of African cassava mosaic virus from plants with dual infections was significantly less than that of East African cassava mosaic virus-Uganda, which may explain the latter’s predominance within the pandemic. These results show that the arrival of East African cassava mosaic virus-Uganda into areas affected previously only by African cassava mosaic virus, has resulted in novel virus/vector/host–plant interactions that drive the pandemic’s continued spread.

Reproductive incompatibility and cytochrome oxidase I gene sequence variability amongst host‐adapted and geographically separate Bemisia tabaci populations (Hemiptera: Aleyrodidae)

Abstract: Reciprocal-crossing experiments were carried out and mitochondrial cytochrome oxidase I gene (mtCOI) sequences were compared for allopatric and sympatric Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) populations collected from Africa and India, and from the host-plants cassava, sweet-potato and a common weed, Euphorbia geniculata. Three incompatible mating groups were discovered, which involved the cassava B. tabaci colonies from Africa and India, the cassava and sweet-potato B. tabaci populations from Uganda, and the cassava and E. geniculata B. tabaci from India. Successful reciprocal mating occurred between cassava-specific B. tabaci from Uganda, Tanzania and Ghana, and between two Indian cassava B. tabaci populations. Thep arsimony and neighbourjoining analyses of 699 bp mtCOI gene sequences divided the colonies primarily into those originating from Africa and India. Further subgrouping corresponded to host-plant specialization. Cassava-specific Ugandan, Tanzanian and Ghanaian colonies formed a single group and the sympatric sweet-potato colony from Uganda grouped separately from them. The two geographically distant Indian cassava B. tabaci populations were similar and formed a single group, whereas the sympatric E. geniculata colony formed a sister clade. The clades generated by the phylogenetic analyses were maintained, with highly supported bootstrap values, when other published mtCOI gene sequences were included in the tree-building process and the divisions matched those revealed by the reciprocal-crossing experiments. These data suggest that biologically discrete populations exist within B. tabaci (sensu Russell, 1957).