bluuebunny/crossref_metadata_2025 huggingface dataset:
The biogeography and historical ecology of Lobelia urens L.(r)(the heath lobelia) in southern England
Authors: Dinsdale Janet , Dale Pamela , Kent Martin
Published: November 2003

This paper examines the past and present ecology and biogeography of Lobelia urens L. (the heath lobelia) which is threatened with extinction in southern England. A survey of the historical and documentary evidence of the distribution of the species is presented. Historical records exist for nineteen sites in the south but nowhere else in England. The status of L. urens is in decline in Britain with ten populations having been lost this century. The six remaining sites have been surveyed to describe the phytosociology of L. urens communities and the variability of the environmental factors controlling its distribution. A total of ninety‐five quadrats containing 122 species were recorded and analysed using two‐way indicator species analysis. Canonical correspondence analysis was used to assess the correlations between twenty‐eight environmental variables and the floristic variation in the ninety‐five quadrats. These were reduced to sixteen variables for the final analysis. L. urens is shown to be a member of rough, grass‐heath communities (NVC M25 and W23) dominated by Molinia caerulea and situated on seasonally waterlogged, moderately acidic, nutrient‐poor soils. The species is suited to both cyclical and sporadic soil disturbance regimes. The final discussion argues that existing populations will only be maintained and expansion of the species distribution occur, if conservationists prevent woodland succession in L. urens sites and periodically disturb the ground in locations where the species survives at present and also where it has been observed in the recent past. This link between historical ecology and present‐day conservation management would appear very important. Further demographic and experimental work is needed to explore these predictions and their implications for the future conservation management of L. urens.
Food supply and breeding occurrences: the West European population of the lekking great snipe Gallinago media (Latham, 1787) (Aves)
Authors: Kålås John Atle , Fiske Peder , Höglund Jacob
Published: November 2003

For species with very high energetic costs during reproduction we expect occurence during the reproduction season to be dramatically affected by the availability of energy. Recent studies have shown very high energetic costs of lekking for great snipe males, Gallinago media (Latham, 1787) and that breeding great snipes prefer to feed in soft soil with a high abundance of earthworms. We here evaluate the hypothesis that the breeding occurrence of great snipe is restricted to areas with very high availability of food. All the 125 registered great snipe leks in Scandinavia were situated in open habitats along the tree line. The occurrence of leks were analysed in relation to bedrock quality, soil chemistry and earthworm biomass. There was a strong positive relationship between soil pH and earthworm biomass. High pH values were found on or in the close vicinity of base‐rich bedrocks. No great snipe leks were documented in areas with acid soil, even if the extent of acid bedrocks along the tree line predicts that 31% of the leks should be situated on acid soils. Hypotheses, including both natural and sexual selection, for why breeding occurrence of great snipe is restricted to areas with high abundance of high quality food are evaluated, and we find indications for this to be a consequence of the very high energetic costs for the lekking males. These costs have probably evolved through female mate choice and indicate that sexual selection may have important consequences for a species distribution. Population‐level effects of sexual selection have previously received little attention. The stringent habitat demands here documented may also make great snipes vulnerable to environmental changes and can contribute to explain the dramatic reduction in breeding range of this species in western Europe during the past 150 years (Løfaldli et al., 1989).
A comparative ecological study of Norwegian mountain plants in relation to possible future climatic change
Authors: Sætersdal Magne , Birks H. J. B.
Published: November 2003

Mountain plants constitute an important part of the Norwegian flora. They are also believed to be the plant group in Norway most threatened by the expected climatic warming due to an enhanced greenhouse effect in the near future. In this study the distributions of 107 mountain Norwegian vascular plants were modelled in relation to present‐day climate using Gaussian logit regression. Most species are found to have a surprisingly broad amplitude to mean July and January temperatures, suggesting that a 2°C increase in summer temperature and 4°C increase in winter temperature (as expected with a 2×CO2 increase) may not have a dramatic direct effect on most of the species investigated. A comparative study between estimated July and January temperature optima and tolerances and other ecological attributes such as habitat characteristics, dispersal mechanisms, range sizes and other climatic optima and tolerances was done using multivariate analysis. The results suggest that species most vulnerable to climatic warming, namely the species with narrow July and January temperature tolerances, are characterized by small range sizes and small population sizes, i.e. they are nationally rare species. Furthermore, these vulnerable species are found in all habitats along the major moisture gradient in alpine vegetation. A classification of the species into Rabinowitz's seven forms of rarity confirms that the species most vulnerable to climatic warming are characterized by being habitat specialists with a small geographic range size.
Land use and forest habitat distribution in the hinterland of(r)a large city
Authors: Matlack Glenn
Published: November 2003

The cumulative effect of many local forest disturbances can be estimated from an analysis of forest distribution at the scale of the entire landscape. To gauge the regional impact of forest clearance and regeneration, a history of forest cover was compiled for the twentieth century in the hinterland of a large city (Wilmington, Delaware, U.S.A.). Forest distribution and character were described by point sampling of historical aerial photographs. Environmental features were measured on visits to sample points in the field. Regional forest coverage has grown from c. 5% in 1890 to 22% in 1990. Most modern stands are <60 years old; only 2.5% of the modern landscape is in forest more than 100 years old. Since 1890, patterns of clearance and regeneration have caused a proportional shift in forest cover from uplands to lowlands and flood plains. Older stands are found on rock fields and steep slopes, indicating abandonment from agriculture according to the quality of local sites. Residential development has been concentrated in uplands, precluding regeneration of forest in that landscape position. In general, land use turnover reflects the character of the local site; there is no evidence of region‐wide gradients of regeneration or clearance. Modern forest is concentrated along steep‐sided stream valleys and away from roads. The great majority of forest lies within 50 m of a forest margin placing it in the microclimatic and vegetational edge zone. Although most forest is within 200 m of a residence, pedestrian traffic appears to have had only a minor impact in the biological community. By contrast, widespread species impoverish‐ ment is suggested by the overwhelming youthfulness of modern forest and the low degree of connectedness of forest within the landscape. Management for biological conservation should focus on protection of remnant primary forest, rather than relying on succession to restock secondary stands.
The seedbanks of the Breckland heaths and heath grasslands, eastern England, and their relationship to the vegetation and the effects of management
Authors: Pakeman R. J. , Marshall A. G.
Published: November 2003

The vegetation and the associated germinable seedbank of a range of heath and grass heath communities in Breckland, eastern England, were compared. The composition of vegetation and seedbank were similar for heather‐dominated communities due to the predominance of Calluna vulgaris. Recent rotovation of previously heather‐dominated communities invaded by Deschampsia flexuosa reduced the number of emerging C. vulgaris seedlings by more than 80%. The composition of seedbanks of calcicolous grasslands differed considerably from the vegetation, with a significant contribution from many ruderal species not present in the vegetation and an absence of important species such as Pilosella officinarum. Acidic grasslands were intermediate between calcicolous grasslands and heather‐dominated heathlands, with seedbanks characterized by high densities of Rumex acetosella and a number of ruderal species that were absent or rare in the vegetation. The composition of the seedbank of more mesotrophic grasslands suggests that the imposition of some form of disturbance may recreate more open grasslands typical of Breckland.
Climatic effect of atmospheric CO2 doubling on radial tree growth in south eastern France
Authors: Keller Thierry , Guiot Joël , Tessier Lucien
Published: November 2003

The climatic effect of a doubling of atmospheric CO2 on radial growth of trees was studied in ten populations of three species in south eastern France using an Atmospheric General Circulation Model (AGCM) predicting a 3°C increase of mean temperature and a light rise of precipitation. Results are based on empirical growth climate models, involving an Artificial Neural Network (ANN) technique. Only two of the studied populations, on the boundaries of their ecological area, are sensitive to the climatic variations. One is the larch (Larix decidua Mill.) population located at 2300 m on elevation (near the timberline) which shows a radial growth increase. The other is the most southern French Scots pine (Pinus sylvestris L.) population which reacts with a severe growth rate reduction.
Postglacial range expansion and population growth of Picea mariana, Picea glauca and Pinus banksiana in the western interior of Canada
Authors: McLeod T. , MacDonald Glen
Published: November 2003

The fossil pollen records from the sediments of thirteen lakes are used to reconstruct the postglacial spread and population expansions of Picea mariana (Mill.) B.S.P., Picea glauca (Moench) Voss and Pinus banksiana Lamb. across the western interior of Canada. The objective of this study was to examine temporal and spatial patterns in the growth of the populations and to determine if intraspecific and interspecific variations exist across a range of latitudes and elevations. Pollen accumulation rates (PARs) are estimated from pollen grain counts and sedimentation rates throughout the early to mid‐Holocene and are used to represent the population level at the time of pollen deposition. Exponential equations are used to calculate population growth rates. Three‐dimensional diagrams (time, space, abundance) are constructed to illustrate range expansion and population growth.The rates of population growth varied from south to north for all three species. Pinus banksiana, on average, had slower population growth rates, and its expansion across the region began over 4000 years later and lasted approximately 1000 years longer than the two Picea species. All three tree taxa experienced reduced rates of population growth at northern high elevation sites. These variations are examined in light of the physical and biological environmental conditions which existed during postglacial range expansion and population growth.
Late Quaternary vegetation and climatic history of eastern Nepal
Authors: Yonebayashi Chuh , Minaki Mutsuhiko
Published: November 2003

The late Quaternary vegetation and climatic history at high altitude in eastern Nepal was studied through stratigraphy, radiocarbon dating and pollen analysis. The Thulo Pokhari lake (27°41′ N, 87°43′ E, ca. 3980 m a.s.l.) is just above the subalpine Abies spectabilis–Betula utilis forest zone and surrounded by Rhododendron scrub. The climate in the studied area is very humid under the influence of the monsoon. Silty sediments suggesting lake conditions prevailed at the lower part of the sediment samples, whereas the upper part consisted mainly of herbaceous peat indicating a mire condition. The pollen record extends back to ca. 11000 yr bp. Although the absence of major changes between the pollen assemblages of the Pleistocene and those in the Holocene was attributed to the situation of the sampling plot above the forest limit, the results suggest the following history. (1) The abundance of Pinus pollen around 11000 yr bp represents expansion of the area unoccupied by late successional trees and/or a drier condition. Significant occurrence of Picea pollen is noteworthy, since this genus is absent in eastern Nepal at present in spite of its wide distribution throughout the neighbouring areas of the Himalayas. (2) The increase in abundance of Quercus pollen and the decline in Pinus pollen in the latest Pleistocene represent climatic amelioration favourable to late successional mesophytes. (3) The climate was most moist and mild in the SP‐III, although the absolute age of the pollen zone is not distinct. The percentages of broadleaved trees such as Alnus, Betula, Carpinus and Corylus were increased at the expense of Quercus and coniferous pollen types. Sedimentation was interrupted by lake level decline and/or glacial advance during the period from ca. 11000–1600 yr bp. (4) The increase in abundance of coniferous pollen types such as Pinus, Abies and Tsuga indicates that the climate became drier and cooler, and the present subalpine forest zone composed of A. spectabilis, T. dumosa and Betula utilis was established around 1600 yr bp. The formation of bog or alpine meadow vegetation during the period was shown by the 14C dates of the peat and the increase in Rosaceae and herbaceous pollen. (5) The increase in abundance of Ericaceae and Alnus pollen in the SP‐V indicates that the present alpine Rhododendron scrub zone has been established since ca. 940 yr bp as a result of human influence on the original vegetation. This interpretation is supported by the decline in the proportion of arboreal pollen. Since the age of the initiation of human influence varies with the altitude and region, further study will be necessary to determine the accurate age.
The distribution and biology of nomadic birds in the Karoo, South Africa
Authors: Dean W.
Published: November 2003

Dryland nomadic bird species, as a proportion of all bird species in a biome in southern Africa, are highest in the arid grassland and arid and semi‐arid Karoo in South Africa. Nomadic birds, of which the most widespread species is the greybacked finchlark Eremopterix verticalis (Smith), are most frequently observed in the north‐central and north western Nama Karoo. The species richness of nomadic species is inversely correlated with species richness of all bird species in the Karoo. Since the distribution of nomadic birds is in areas where rainfall is patchy, low (<250 mm per year) and aseasonal, this supports the idea that fewer species are able to cope with resources that are patchy in time and space, and that there has been selection for nomadism in the species that are able to use patchy environments. Species richness and abundance of nomadic birds is negatively correlated with rainfall amount but positively correlated with the coefficient of variation of the rainfall and with rainfall in autumn. The frequency of nomadic birds is inversely correlated with altitude range; nomadic species are most often recorded in structurally simple habitats (shrubland and grassland) on open plains. Most nomadic bird species in the Karoo are granivorous. Perennial desert grasses are important components of the habitat and diet of small nomadic granivores, and also provide nest sites and nest material. Nomadic birds can breed throughout the year, without a clearly defined ‘season’ in both the Succulent and Nama Karoo. Average clutch sizes do not differ significantly between resident and all nomadic species in the arid and semi‐arid Karoo. Nomadism is an evolutionary stable strategy for individual species only when extremes in environmental conditions are frequent enough, and unpredictable enough, to maintain movements to high resource patches or to maintain dispersal away from low resource patches. If high rainfall years are too regular or infrequent, or peaks in fluctuations of resources in the environment too low, or rainfall patches are randomly distributed, nomadism would not be maintained as part of the individual behaviour pattern.
An analysis of pupils’ reflective writing within a hypermedia framework
Authors: Deadman G.
Published: November 2003

This paper is based on an action research project which was undertaken in order to explore further the ways in which reflective writing supports pupils’ learning. The emphasis here is on one part of the research which involved an analysis of pupils’ writing. Twenty four pupils, in one GCSE group, were given two writing activities. The first activity required pupils to write up their work with support from the teacher. The second activity involved pupils writing up their work with support both from the teacher and from a hypermedia reflective writing framework. The writing was then analysed sentence by sentence and the results compared. This comparison suggests that there were improvements in pupils’ ability to reason when they were further supported by a hypermedia reflective writing framework.
A hypermedia system to aid teacher understanding of pupil preconceptions
Authors: Wiles N. , Wright D.
Published: November 2003

The paper reports on the initial development of a hypermedia environment aimed at teachers. The system uses constructivist learning principles to discover the preconceptions held by teachers about fundamental electrical principles. The interface is designed to be as transparent and non‐threatening as possible, thus allowing the users to concentrate on content. The system which was prototyped in SuperCard has generated positive feedback from the eventual end users.
A framework for understanding learning from management simulations
Authors: Tonks D. , Armitage S.
Published: November 2003

Article proposes a framework for understanding certain aspects of learning from computer‐based management simulations. The framework is developed as a result of small‐scale, exploratory research amongst postgraduate students at three European Business Schools. An overview from the general literature on management learning is provided and claims made in the specific literature regarding student learning from management simulations are considered. There is reference to the methodological problems associated with establishing learning outcomes. The need to conduct research into the learning experience from the student perspective is argued. A framework for mapping student perceptions of management simulation learning is developed using the established notions of learning style and depth of learning. Data from the exploratory research are used as illustration for the framework.
Manipulable graphics for computer‐supported problem solving
Authors: Reinhard P. , Hesse F. W. , Hron A. , Picard E.
Published: November 2003

The use of computer graphics for problem solving was investigated during use by individual learners and by distant pairs collaborating by interaction through the screen. In both investigations learners had to correct computer graphics representing population models, either by graphical manipulation or by written explanation. In both situations positive effects of manipulable graphics on problem solving performance were found. However, a detailed analysis of the interaction processes in the collaborative situation showed that, comparing both experimental conditions, static graphics led to a higher proportion of correct content‐related statements and explanations of system relations. No differences were observed between both conditions on the participation structure within the learning dyads. The results suggest that for the effective use of graphics in computer‐supported collaborative learning, structural support devices that encourage adequate processing and focus learners on the problem solving process seem to be necessary.
Computer‐mediated communication as a learning resource
Authors: McAteer E. , Tolmie A. , Duffy C. , Corbett J.
Published: November 2003

Evaluative studies of CMC can produce misleading or even contradictory results due to an (understandable) focus on how the characteristics of the medium affect usage, ignoring the dialectic between technology and culture, of mutual adaptation over time. CMC exchanges in Higher Education take place within a broad teaching and learning system, of which most participants already have extensive experience. This system provides the context within which participants make sense of, and adapt to, the use of on‐line communications. Thus interpretations of the processes shaping exchanges and their outcomes have to take into account: who participants see themselves as communicating with and why, how this serves longer‐term learning goals, and what past experience of engaging with both task and audience they have had; what kinds of exchange are facilitated, both by the medium itself and how the task is organised, and how such affordances are honed over time; and also, how these interactions impact on other aspects of teaching and on learning outcomes.
Computer mediated tutorial support for conventional university courses
Authors: Light P. , Colbourn C. , Light V.
Published: November 2003

In an effort to restore quality and flexibility to the tutorial provision on some undergraduate courses, first, second and third year psychology students at the University of Southampton have been inducted into the use of ‘skywriting’ as a medium for learning support. Email messages from students and tutors, primarily focussed on issues arising from the course content, are directed to a course list so that all participants receive them; both tutors and students may reply to these. The course tutor maintains a Web‐based archive of threaded discussions by the occasional modification of message subject lines. Within this archive, the exchanges can be searched and read by theme, by participant, or by date. This provision is in addition to the usual lectures and face‐to‐face tutorial meetings. This paper examines students’ participation in skywriting on three courses. Participation is examined in relation to gender, and to attitudes and experience with computers. Levels of contribution to face‐to‐face tutorials and to skywriting are compared, and their relation to students’ learning styles is explored.
Evaluating a virtual summer school
Authors: Issroff K. , Eisenstadt M.
Published: November 2003

The Open University’s Virtual Summer School took place in 1994 and was an experimental project which aimed to use technology to support students who were unable to attend a conventional campus‐based summer school. Students on many courses at the Open University are expected to attend summer school, but for some students this is impossible. In the Virtual Summer School, 12 students used a wide range of software to communicate with tutors and each other, attend lectures and tutorials, access resources and complete projects in groups. The students were studying Cognitive Psychology and the work involved a range of activities including programming, carrying out experiments and statistical analysis. The evaluation used a series of questionnaires to the students, which were compared with those of students at conventional summer school. This paper provides an overview of the Virtual Summer School, presents a selection of the results of the evaluation and discusses the issues which arose out of the evaluation.
Monitoring a CMC environment created for distance learning
Authors: Wilson T. , Whitelock D.
Published: November 2003

Projects using Computer Mediated Communication (CMC) are becoming of interest to all academic institutions World‐wide. STILE (Students’ and Teachers’ Integrated Learning Environment) is one such project which included four universities in the United Kingdom. The Open University implementation of the project was called M205‐STILE and it used a CMC environment with 110 students and nine tutors nationwide and in Europe. The participants were on‐line from February to October 1995 and the provision of these facilities allowed distance learning students to avail themselves of better communication with both their tutor and with fellow students. This paper discusses, from both the tutor and student perspective, how computer science students made use of a CMC environment created especially for them. It illustrates that students used the system to learn more about the subject area and about each other, and to sustain or motivate themselves throughout the learning period.
Gender, identity and CMC
Authors: Yates S. J.
Published: November 2003

This paper re‐examines a number of recent discussions of computer‐mediated communication (CMC) in the light of debates concerning gender, identity and inequality. There have been many claims made by disparate groups and institutions, from educators and technologists, through to the advertising of communications companies, which have claimed that CMC‐based interactions lack the overt structures of inequality found in other communicative situations. This ideology of ‘on‐line equality’ is partly based upon a number of research findings, as well as popularised accounts of ‘life on the screen’. Set against this is a growing body of research into CMC and gender, as well as other structures of inequality, which has made apparent the differences in both access and practice. By re‐examining the various claims underlying both positions, as well as deploying recent research into the cultural aspects of gender identities, this paper aims to make clear the centrality of gender to CMC interactions.
Variations in the management of cancer in the NHS: a legitimate cause for concern?
Authors: Kunkler I. H.
Published: November 2003

Wide variations still exist in the UK in the management of common cancers in adults. Comprehensive high‐quality audit data are needed to relate variations in outcomes to differences in clinical management. The management of cancer in the elderly is often difficult due to co‐morbidity. Access to oncological advice should be available to all patients irrespective of age. Development of and adherence to nationally agreed treatment protocols is a key measure in reducing variations in treatment and in outcomes for patients with cancer.
Breast cancer screening in younger women: evidence and decision making
Authors: Elwood J. Mark
Published: November 2003

Contrasting conclusions on the efficacy of routine breast cancer screening in younger women, under age 50, have been produced by expert and influential groups, particularly in the United States. In an international workshop in 1993, and again at a consensus development conference in 1997, the National Institutes of Health and the National Cancer Institute concluded that evidence for efficacy was uncertain, and routine screening could not be recommended. The 1997 conference concluded that the individual decision had to be made by each woman and her health care provider. In contrast, the American Cancer Society has advocated routine screening, despite accepting that the randomized trial evidence does not clearly support it. The decision of the 1997 NCI consensus conference has been rejected by the director of the NCI, and a similar controversy occurred in 1993. On two occasions, US Senate subcommittees have affirmed support for screening and criticized the conclusions of expert groups. In this paper, the arguments raised in these discussions, and the differing ways in which scientific evidence has been assessed, are discussed.
A systems analysis approach to medical error
Authors: Leape Lucian L.
Published: November 2003

Evidence from various sources indicates that a substantial number of hospitalized patients suffer treatment‐caused injuries. Most of these injuries result from errors. Yet physicians and other health professionals have been reluctant to admit and address the problem of errors, both because of feelings of guilt and from the desire to avoid punishment or disapproval by colleagues. Research in cognitive psychology and human factors has shown that most errors result from defects in the systems in which we work. These are failures in the design of processes, tasks, training, and conditions of work that make errors more likely. Meaningful reduction of errors requires correction of these systems failures. Barriers to reduction of errors include the complexity of health care systems, difficulties in information access, tolerance of stylistic practices, and fear of punishment that inhibits reporting. Most institutions also lack effective methods for detecting and quantifying errors. Significant improvements in error reduction will require major commitments by organizational leadership and the recognition that errors are evidence of deficiencies in systems, not deficiencies in people.
Audit: an exploration of two models from outside the health care environment
Authors: Earl‐Slater Alan , Wilcox Victoria
Published: November 2003

Whilst there has been exponential growth in auditing health care services and a proliferation of the instruments involved, there seems to have been less cross‐fertilization of audit systems and instruments between health care environments and other environments. This paper identifies and explores two audit systems and instruments outside the health care environment. The objective is to seek to improve the level of common understanding, communication and collaboration amongst those who are interested or involved in audit in any sector of the economy. This exercise offers an opportunity and incentive for cross‐fertilization of ideas with respect to audit concepts, systems, instruments, results and experiences.

Yet there is a more fundamental question to be considered: why bother with audit? This paper identifies core reasons for performing audit which, although they have been mentioned elsewhere, are worth recalling once again. The two non‐health care audit systems and instruments are then identified and explored. On the one hand it is seen that the two audit systems and instruments outside health care have common features with audits in health care. On the other hand, it is also suggested that there are some significant differences in the two audit systems and instruments when compared to health care audits. This paper identifies and discusses similarities and differences.

Finally, if we fail to learn from the mixture of experiences and insights of various audit exercises, not only will be doing our professions and our customers a disservice but we will lower the chances of continuous improvement in knowledge and understanding.
Evaluation of changes in primary health care availability and provision from the patient perspective
Authors: Jones Dee , West Robert , Lester Carolyn
Published: November 2003

This study was designed to investigate changes in primary care following recent NHS reforms. The study was carried out by home interview of random samples of people aged 65 years and over in three district health authorities; 1500 in 1990 and 1500 in 1992, before and after the introduction of the reforms. The response rate was 94% (1413 in 1990 and 1405 in 1992). Few patients (6%) changed their general practitioner (GP) in 1990 or 1992. There was an increase in the provision of written practice information in 1992, but more than 60% of patients could not recall receiving leaflets. More practices included practice nurses and appointments systems and fewer used rotas of local practices or deputizing services for ‘out of hours’ calls. In 1992 more patients aged 75 years and over saw their GP within the previous year and significantly more were assessed for vision, hearing, continence, foot problems and blood pressure and had their urine tested, but most of these health assessments, except blood pressure (64%), were recalled by few patients. There have been small changes in the provision and use of primary health care by older people since the introduction of the new GP contract.
Studies of the ultrastructure and morphogenesis of fish pathogenic viruses grown in cell culture
Authors: Granzow H. , Weiland F. , Fichtner D. , Enzmann P.J.
Published: November 2003

A birnavirus (infectious pancreatic necrosis virus, IPNV), three rhabdoviruses (viral haemorrhagic septicaemia virus, VHSV; infectious haematopoietic necrosis virus, IHNV; and spring viraemia of carp virus, SVCV) and an iridovirus (isolate from a sheatfish) were investigated with regard to their morphogenetic interactions with cells in culture. In cells infected with birnavirus, a granular viromatrix, single virions randomly distributed in the cytoplasm, viral particles aggregated in pseudocrystals and cytoplasmic tubuli similar in diameter to that of the virus were found. Rhabdoviruses entered the cells by viropexis and replicated within the cytoplasm. Maturation occurred predominantly at the cell membrane and sporadically at membranes of the Golgi cisternae. Inclusion bodies were found partially consisting of viral nucleocapsids. After budding, new virions were found adsorbed to the cell membrane. Viral haemorrhagic septicaemia virus, known to exhibit an atypical shape because of preparative procedures, could be identified by immunostaining using two monoclonal antibodies directed against G‐ and N‐proteins and colloidal gold. Iridoviruses entered the cells by viropexis. Viral particles were found in coated vesicles. Subsequently, vesicles without a clathrin coat were detected. Replication occurred within prominent cytoplasmic inclusion bodies. Isometric viral nucleocapsids were transported in an unknown manner to the cell membrane and matured by budding.
The host transfer ability of Lepeophtheirus salmonis (Copepoda: Caligidae) from farmed Atlantic salmon, Salmo salar L.
Authors: Ritchie G
Published: November 2003

The ability of mobile stages of Lepeophtheirus salmonis to transfer between salmon, Salmo salar L., hosts was examined by two methods. The first of these was the removal of certain stages on farmed fish, while the second comprised the placement of mobile lice on clean fish in the laboratory. In one‐sea‐winter farmed salmon, 63% of males and 52% of female lice transferred to new hosts over a period of 4 days. In laboratory trials on post‐smolts, 61% of males and 69% of female lice transferred to new hosts over 3 days. In another experiment, free‐swimming adult male lice were added to the tank, and 90% of these were found on fish after 24 h. Immigration of lice to fish in trial cages and the large proportion of lice transferring between fish in both laboratory and farm trials indicates that L. salmonis can transfer between hosts.
Estimation of variation of virulence of Renibacterium salmoninarum by survival analysis of experimental infection of salmonid fish
Authors: Dale O B , Gutenberger S K , Rohovec J S
Published: November 2003

The variation of virulence of Renibacterium salmoninarum, the causative agent of bacterial kidney disease (BKD) in salmonid fish, was studied by infecting rainbow trout, Oncorhynchus mykiss (Walbaum), with two isolates (strains 325 and 932) from diseased Atlantic salmon, Salmo salar L., and one isolate (strain 4366) from an apparently healthy Atlantic salmon. Coho salmon, Oncorhynchus kisutch (Walbaum), were injected with the strain 932 to estimate difference in fish species resistance. Fish were removed by random sampling for other study purposes, a study design possible with analysis of lifetime distributions incorporating both sampling‐, death‐ and survival‐times. At the end of the experiment, the rainbow trout infected with strains 325, 932 and 4366 had a survival probability of 33%, 51% and 72%, respectively. The coho salmon infected with strain 932 had a 26% survival probability. The strain differences were significant according to the log‐rank test, and the risk ratio between the strains ranged from 1·8 to 5·4. The strain from the apparently healthy fish was least virulent. The survival of the fish species was different over time. Rainbow trout were more likely to die early in the time course, but high numbers of coho died later, resulting in an overall risk of mortality of 1·4 in favour of rainbow trout. Differences in virulence may reflect changed selective pressure on R. salmoninarum when introduced from feral stocks into the environment of fish farms.
Mass mortalities associated with viral nervous necrosis (VNN) disease in two species of hatchery‐reared grouper, Epinephelus fuscogutatus and Epinephelus akaara (Temminck & Schlegel)
Authors: Chi S C , Lo C F , Kou G H , Chang P S , Peng S E , Chen S N
Published: November 2003

Mass mortalities of hatchery‐reared juvenile groupers have occurred in southern Taiwan. The diseased fish swam in a darting, corkscrew fashion. Light microscopy revealed vacuolation in the brain tissue. Electron microscopy showed numerous non‐enveloped, cytoplasmic viral particles (20–25 nm in diameter) in the brain cells, and many virions were enclosed in the membrane‐bound organelles of the cells. Two structural proteins of the purified grouper virus, with molecular weights of 44 and 43 kDa, were revealed by SDS‐PAGE. Moreover, the results of RT‐PCR and nested PCR diagnosis using primers specific to the T2 and T4 target segments of striped jack nervous necrosis virus (SJNNV) RNA2 genes suggest that this virus is a fish nodavirus, and is designated as GNNV 9410 strain (grouper nervous necrosis virus strain 9410). This is the first case report of viral nervous necrosis among marine fish in Taiwan.
Infectious pancreatic necrosis virus in the environment: relationship to effluent from aquaculture facilities
Authors: McAllister P E , Bebak J
Published: November 2003

Effluents from three fish hatcheries were monitored for the discharge and subsequent downstream distribution of infectious pancreatic necrosis virus (IPNV). Samples of springwater and surface water, and tissues from salmonid and non‐salmonid fish were assayed for IPNV. Water samples were processed to recover virus by adsorption to an electropositive, microporous filter matrix. No IPNV was detected in surface water collected above fish hatcheries or in hatchery springwater supplies. The virus could be detected for at least 19.3 km below the point of effluent discharge from hatcheries and the prevalence of IPNV infection in stream‐resident fish was 2.8%.
Light and electron microscopic evidence of white spot disease in the giant tiger shrimp, Penaeus monodon (Fabricius), and the kuruma shrimp, Penaeus japonicus (Bate), cultured in Taiwan
Authors: Wang C S , Tang K F J , Kou G H , Chen S N
Published: November 2003

Since 1992, mass mortalities among cultured giant tiger shrimp, Penaeus monodon (Fabricius), and kuruma shrimp, Penaeus japonicus (Bate), have been observed in Taiwan. The condition is known as ‘white spot disease’ (WSD), based on the characteristic white spots on the cuticle of diseased shrimp. With the scanning electron microscope, two sizes of white spots were observed. Each spot represented a protrusion on the inside surface of the carapace. The composition of white spots was similar to that of the cuticule, most calcium, as determined with an energy dispersive spectrometer. Histological studies of moribund, infected specimens revealed degenerated cells, characterized by hypertrophied nuclei, in various meso‐ and ectodermal tissues. Infected tissues included cuticular epidermis, connective tissue, lymphoid organ, antennal gland, and haematopoietic, gill and nervous tissue. Nuclei were Feulgen‐positive and no occlusion body was found in the necrotic tissue. Transmission electron microscopy revealed the presence of rod‐shaped and enveloped virions in the hypertrophied nuclei. The virions measured 298 ± 21 × 107 ± 8 nm in the giant tiger shrimp and 248 ± 12 × 104 ± 8 nm in the kuruma shrimp. In an experimental infection trial, cumulative mortality was 40% within 14 days under stress conditions. No mortality was observed in controls or in non‐stressed infected shrimp. Experimental infections show that environmental stressors such as ammonia may enhance the severity of WSD virus infections in cultured shrimp.
Non‐specific defence mechanisms in fish, with particular reference to the reticuloendothelial system (RES)
Authors: Dalmo R.A. , Ingebrigtsen K. , Bøgwald J.
Published: November 2003

An efficient clearance and degradation system may be needed during microbial invasion which otherwise would lead to severe inflammation and eventually death. Non‐specific defence mechanisms in fish play an important role at all stages in infection. The non‐specific humoral defence including proteases, lysins and agglutinins, for example, in mucosal secretion is the first line of defence, whereas mucosal lining cells function as the second barrier against invasion. Blood cells, especially granulocytes and monocytes, may destroy microbes present in the circulation and may function as the third line of defence. Finally, endocytically active cells such as endothelial cells, macrophages and granulocytes in organs and tissues may take up and degrade microbes or microbial products. The endocytic and degradation processes strongly depend on the effectiveness of the reticuloendothelial system which consists of endothelial cells and macrophages that line small blood vessels (e.g. sinusoids and ellipsoids). Potentiation of non‐specific defence mechanisms may occur during microbial invasion, leading to more efficient clearance and destruction of pathogens or other harmful substances. In microbial invasion, an inflammatory response such as elevated production of antimicrobial substances is often encountered. Central cells in the production of antimicrobial substances are macrophages and granulocytes, and microbial products in inflammation may alter the cells function to a more activated state in vivo. Activated cells may enhance their antimicrobial capacity and efficiency by producing higher amounts and more active antimicrobial agents. This review concerns the non‐specific defence system and gives an introduction to some of the known non‐specific humoral substances and their induction/suppression, and provides a more extensive introduction to cytokine research and immunomodulation. Cellular aspects of non‐specific defence, including macrophages and their products, are discussed in the light of their function in the reticuloendothelial system in fish.
Evaluation of cross protection by vaccines against atypical and typical furunculosis in Atlantic salmon, Salmo salar L.
Authors: Gudmundsdóttir B K , Gudmundsdóttir S
Published: November 2003

In Iceland, farmed salmonids are vaccinated against A. salmonicida ssp. achromogenes (Asa), which causes atypical furunculosis and is endemic in local waters. Classical furunculosis, caused by A. salmonicida ssp. salmonicida (Ass), was not diagnosed in this country until June 1995. In the present study, protection in experimental challenges against atypical and classical furunculosis in Atlantic salmon vaccinated with an autogenous Asa bacterin (Iceland Biojec.OO, IBOO), a commercial furunculosis vaccine (Biojec.1500), or a mixture of both vaccines was compared. The results showed that both vaccines gave protection against an injection challenge with Asa. However, better protection was obtained with the IBOO (homologous) vaccine. Infection of Asa by cohabitation could not be established in fresh water. Fish vaccinated with Biojec.1500 or with both vaccines simultaneously were equally well protected against Ass in a cohabitation challenge. On the other hand, no protection against classical furunculosis was achieved in fish vaccinated by IBOO alone.
Vaccination of rainbow trout, Oncorhynchus mykiss (Walbaum), against cryptobiosis: efficacy of the vaccine in fresh and sea water
Authors: Li S , Woo P T K
Published: November 2003

Adult rainbow trout, Oncorhynchus mykiss (Walbaum), maintained in either fresh or sea water were vaccinated with a live Cryptobia salmositica vaccine. All vaccinated fish were protected 4 weeks later against the cryptobiosis, while unvaccinated rainbow trout developed the disease (e.g. high parasitaemia and severe anaemia) after challenge with virulent C. salmositica. There was also no disease in vaccinated fish when they were transferred from fresh to sea water immediately after vaccination. Complement fixing antibodies (CFAbs) were detected in vaccinated fish and the CFAbs lysed parasites under in vitro conditions. The antibody titres increased rapidly at one week post‐challenge in vaccinated fish in fresh water and vaccinated fish transferred from fresh water to sea water after vaccination. However, the production of CFAbs was delayed by one week in vaccinated fish in sea water and the antibody titre was significantly lower than that in fish maintained in fresh water.
Colonization in the fish intestinal tract and production of inhibitory substances in intestinal mucus and faecal extracts by Carnobacterium sp. strain K1
Authors: Jöborn A , Olsson J C , Westerdahl A , Conway P L , Kjelleberg S
Published: November 2003

A non‐virulent Carnobacterium sp., designated strain K1, isolated from the gastrointestinal tract of Atlantic salmon, Salmo salar L., which produced inhibitory substances against bacterial fish pathogens, was examined in vitro for characteristics important for the colonization of the fish gastrointestinal tract and in vivo for persistence in the tract after oral dosing. In vitro growth experiments showed that the cells of this strain were metabolically active in both the intestinal mucus and faeces from salmonids. The production of growth inhibitors against the two common fish pathogens Vibrio anguillarum and Aeromonas salmonicida by Carnobacterium sp. strain K1 was demonstrated in vitro in mucus and faecal extracts. Furthermore, it was demonstrated that the Carnobacterium cells remained viable in the gastrointestinal tract for several days and that no detrimental effect to the fish was observed as a result of the presence of the bacterium.
Jaw ulcers in Atlantic tomcod, Microgadus tomcod (Walbaum), from the St Lawrence River
Authors: Lair S. , Mailhot Y. , Higgins R. , Élanger D.B. , Berthiaume L. , De Lafontaine Y. , Martineau D.
Published: November 2003

A survey of external lesions on Atlantic tomcod from the St Lawrence River was carried out between mid‐December 1992 and the end of January 1993 (n = 1674). Jaw ulcerations were observed in 3.8% of the fish. These ulcers were usually single, and located at the junction between the skin epidermis and oral mucosa. They progressed from shallow lesions to deep ulcers with pathological fracture of the facial bone secondary to osteitis. The aetiology of these lesions could not be determined. Fish with ulcers were generally older than those of the monitored spawning population. The reason for a higher prevalence in older tomcods is unknown, but decreased immune functions and healing capacity caused by ageing are suggested as potential predisposing factors.