bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant diversity affects culturable soil bacteria in experimental grassland communities
Authors: Stephan André , Meyer Andrea H. , Schmid Bernhard 
Published: March 2003

Summary1 Utilization of carbon sources by culturable soil bacteria can be assessed with BIOLOG microtiter plates (contain 31 C sources). We used this technique to investigate bacterial community structure at various levels of plant diversity. Plant diversity levels were replicated and we investigated the influence of three plant functional groups, grasses, legumes and non‐leguminous herbs, as well as the influence of individual plant species.2 Catabolic activity and catabolic diversity of culturable soil bacteria were used to estimate their density (abundance) and functional diversity, respectively. Both increased linearly with the logarithm of plant species number and with the number of plant functional groups in experimental grassland ecosystems. These effects may have been caused by an increased diversity and quantity of material and energy flows to the soil. They may also have been mediated by increased diversity of soil microhabitats via a stimulation of the soil fauna.3 The presence of particular plant species or functional groups in the different experimental communities stimulated the activity and functional diversity of the culturable soil bacteria in addition to their contribution via plant diversity. The legumeTrifolium repenshad the strongest effect and may be regarded as a keystone species with regard to plant–microbial interactions in the systems studied.
Palaeovegetation‐model comparisons, climate change and tree succession in Scandinavia over the past 1500 years
Authors: Cowling Sharon A. , Sykes Martin T. , Bradshaw Richard H. W. 
Published: March 2003

Abstract

We assess the robustness of a 1500‐year palaeoclimate data base and forest gap model in simulating northern Scandinavian boreal forest succession since ad 500. We also evaluate trends in species abundance in a nemoral woodland in southern Scandinavia by comparing modelling results to palaeoecological data.
Simulated biomass trends for Picea, Pinus and Betula growing at Penningholmen (northern Sweden) are strikingly similar to those observed in the local pollen record, particularly in the replication of the early Little Ice Age (LIA) decline in Betula and the late‐LIA dieback of Picea and Pinus.
LIA decreases in Betula may therefore be partly due to the effects of climate on its competitive interactions with Pinus, as well as the previously proposed effects of insect herbivory.
Simulations of Draved Forest (western Denmark), suggest that Tilia is under‐represented in modern‐day Scandinavian nemoral woodlands, and consequently that the present dominance of Fagus probably reflects strong human–plant interactions from as early as the beginning of the 17th century.
This study highlights the importance, despite general limitations associated with vegetation models, of model‐data comparisons for understanding mechanisms and processes underlying past forest succession, and emphasizes the usefulness of forest models for reconstructing climate influences on past vegetation.
Population dynamics and stage structure in a haploid‐diploid red seaweed,Gracilaria gracilis
Authors: Engel Carolyn , Åberg Per , Gaggiotti Oscar E. , Destombe Christophe , Valero Myriam 
Published: March 2003

Summary Many red seaweeds are characterized by a haploid‐diploid life cycle in which populations consist of dioecious haploid (gametophyte) and diploid (tetrasporophyte) individuals as well as an additional diploid zygote‐derived sporangium (carposporophyte) stage. A demographic analysis ofGracilaria gracilispopulations was carried out to explore and evaluate the population dynamics and stage structure of a typical haploid‐diploid red seaweed. FourG. gracilispopulations were studied at two sites on the French coast of the Strait of Dover. Survival, reproduction and recruitment rates were measured in each population for up to 4 years. Eight two‐sex stage‐based population projection matrices were built to describe their demography. All four populations were characterized by high survival and low recruitment rates. Population growth rates (λ) were similar between populations and between years and ranged from 1.03 to 1.17. In addition, generation times were found to be as long as 42 years. Sex and ploidy ratios were variable across populations and over time. Female frequencies ranged from 0.31 to 0.59 and tetrasporophyte frequencies from 0.44 to 0.63. However, in most cases, the observed population structures were not significantly different from the calculated stage distributions. Eigenvalue elasticity analysis showed that λ was most sensitive to changes in matrix transitions that corresponded to survival of the gametophyte and tetrasporophyte stages. In contrast, the contribution of the fertility elements to λ was small. Eigenvector elasticity analysis also showed that survival elements had the greatest impact on sex and ploidy ratios.
The higher availability of N and P in lime‐poor than in lime‐rich coastal dunes in the Netherlands
Authors: Kooijman A. M. , Besse M. 
Published: March 2003

Summary1 Measurements of above‐ground productivity, plant nutrient levels,in situmineralization and litter decomposition in four localities differing in soil chemical conditions were used to assess the availability of N and P in Dutch coastal dune grasslands.2 P‐availability is regulated by soil chemical conditions and seems to be a key factor regulating biomass production, whereas N‐availability seems to be determined by litter input from this biomass, and thus indirectly controlled by P.3 Contrary to expectation, N‐availability is much higher in acid soils (with low rates of decomposition and high soil C : N ratios) than in calcareous soils (with high decomposition and low C : N ratios). Similar results have been reported from other ecosystems and may be due to a lower microbial N‐demand at low rates of decomposition, increasing the amount of N left over for the vegetation.4 In contrast to ‘conventional wisdom’, low‐degradable litter may be a good plant strategy to improve the ecosystem recycling of nutrients and increase their availability. This may at least partly explain the success ofAmmophila arenariain lime‐ and iron‐poor dunes.
Spatially realistic plant metapopulation models and the colonization–competition trade‐off
Authors: Higgins Steven I. , Cain Michael L. 
Published: March 2003

Summary

Results from patch‐occupancy metapopulation models indicate that a trade‐off between competitive and colonization abilities is necessary for species to coexist in patchy environments. However, such models are often based on unrealistic ecological assumptions, such as global dispersal and no local population dynamics.
We develop a plant metapopulation model that allows us to sequentially relax unrealistic assumptions about dispersal and local population interactions. We use our model to examine the extent to which the conclusions of analytical, patch‐based coexistence models depend on their assumptions.
We found that the need for an inferior competitor to be a superior colonizer was reduced by using a dispersal kernel to distribute seeds, and totally removed by relaxing the assumption of instantaneous competitive displacement. These results hold for annual or perennial plants with or without seedbanks, for global, local and stratified dispersal, for delayed competitive exclusion, two‐way competition and neighbourhood competition, and for landscapes where habitat patches are either adjacent or disjunct.
We conclude that the results of patch‐occupancy metapopulation models differ greatly from results of models that incorporate more realistic assumptions about dispersal and local population dynamics. As a result it may be premature to base biodiversity management and policy on the results of patch‐occupancy models.
Demographic consequences of inbreeding and outbreeding inArnica montana: a field experiment
Authors: Luijten Sheila H. , Kéry Marc , Oostermeijer J. Gerard B. , Den Nijs Hans (J.) C. M. 
Published: March 2003

SummaryThe genetic constitution of populations may significantly affect demography. Founder populations or isolated remnants may show inbreeding depression, while established populations can be strongly adapted to the local environment. Gene exchange between populations can lead to better performance if heterozygosity levels are restored (heterosis), or to reduced performance if coadapted gene complexes are disrupted (outbreeding depression).Five populations of the self‐incompatible perennialArnica montana(Asteraceae) were analysed for the demographic consequences of inbreeding and of intra‐ and interpopulation outcrossing, using both small and large populations as donors for the latter. We analysed seed production and seed weight and monitored growth, survival and flowering of offspring introduced as seeds and as 4‐week‐old seedlings in a 4‐year field experiment.Reduced seed set after selfing was probably due to the self‐incompatibility system rather than to inbreeding depression. There was a significant increase for seed set after interpopulation crosses, which resulted from the alleviation of low mate availability in one of the small populations.Significant inbreeding depression was observed for growth rates of plants introduced as seedlings. We found significant heterosis for flowering probability of plants introduced as seeds, but for plants introduced as seedlings, heterosis for seedling size and flowering probability was only marginally significant. Outbreeding depression was not observed.The results of this study are important for reinforcement measures in small, remnant populations. Significant differences among populations for all measured fitness components suggest that reinforcement is best achieved using material from several populations.The observed higher survival of seedlings as compared with seeds suggests that it is better to plant individuals than to sow. Sowing, however, is easier and cheaper, and was more likely to eliminate poorly adapted genotypes before they contribute to the next generation.
What is action research and can it promote change in primary care?
Authors: Hampshire A. J. 
Published: March 2003

AbstractImproving the quality of health care is an international priority. However, research has shown that methods of altering clinician's behaviour or implementing organizational change are often ineffective. Action research has been used successfully to facilitate change and improve service provision in industry, education and more recently in health care. In this paper, action research methodology and why it should be successful in promoting change are outlined. Recently published studies using action research in the primary health care team setting in the UK are discussed. They demonstrate that action research improves clinical care, teamwork, communication and administration. It also encourages practice teams to audit their work and identify their educational needs. The main problems encountered were the amount of time and effort required to maintain collaboration with participants, staff turnover and completing the research process in a short time scale. Action research should be a useful means of improving quality in health care and could be used more widely. In the UK, government strategy has called for individual‐ and team‐based development plans based on individual learning needs. Action research could be a useful method of transforming these from theory to practice.
An evidence‐based approach to drainage of the pleural cavity: evaluation of best practice
Authors: Tang Augustine T. M. , Velissaris Theodore J. , Weeden David F. 
Published: March 2003

AbstractRecent surveys have uncovered major variations in key aspects of intercostal drain management, suggesting that decisions are being made on individual preferences without resorting to sound evidence. We provide an up‐to‐date review of the best practice with evidence‐based recommendations and expert consensus views. The following aspects of chest drain management have been addressed: indications for drainage, insertion technique, complications, management of an indwelling chest drain, indications and technique for removal. The emphasis in this review is that safe intercostal drain practice relies upon adherence to a few important principles. Furthermore, when in doubt, particularly with a complex thoracic problem, one should seek prompt specialist advice.
Calman–Hine reassessed: a survey of cancer network development in England, 1999–2000
Authors: PhD Beth Kewell BA ,   Chris Hawkins MA BA Grad Dip Phys MCSP SRP, PhD Ewan Ferlie BA 
Published: March 2003

Abstract Rationale, aims and objectives The paper assesses preliminary national data on the development of cancer care networks in England. Methods In January 2000, a national postal survey was sent to lead clinicians at 36 cancer centres and associate centres. Respondents were asked to provide basic numerical data on the design of the network (i.e. its configuration), detailing how many units it encompassed, and whether the centre was a multiple or a single entity. Results The survey highlighted national variations in the size and configuration of networks. The survey also highlighted tentative signs of shifts in clinical practice. The results showed that consultants at cancer centres and units were engaging in two forms of collaboration across centre–unit boundaries. Type 1 involved routine multidisciplinary team (MDT) outreach from centres to units, incorporating joint planning between clinicians at cancer centres and cancer units. Type 2 collaboration involved joint planning but also promoted joint centre and unit training and continuing professional development (CPD) programmes. Conclusions In our estimation, both forms of collaboration represented early evidence of qualitative changes in medical working practices. Organizational changes within cancer services have moved swiftly since initial soundings were taken in 2000 and we update our initial commentary in the light of recent empirical data. The findings may be of wider significance to managers and health practitioners who are working towards the implementation of delivery network elsewhere in the UK National Health Service.
Influence of combined vitamins C and E on non‐specific immunity and disease resistance of rainbow trout, Oncorhynchus mykiss (Walbaum)
Authors: Wahli  , Verlhac  , Gabaudan  , Schüep  , Meier  
Published: March 2003

AbstractThe effect of various combinations of vitamins C and E on immune response and disease resistance was investigated in rainbow trout, Oncorhynchus mykiss (Walbaum). The following combinations of vitamins were included in the diet (C/E): 0/0, 0/800, 2000/0, 30/30, 30/800, 2000/30, 2000/800. Liver ascorbic acid and alpha‐tocopherol contents reflected the dietary treatments well. Complement levels showed no significant differences. The combination of the high dietary doses of vitamins C and E significantly stimulated lymphoproliferation induced by Concanavalin A when compared with fish fed a low level of both vitamins, but also when compared with fish fed a low level of vitamin C and a high level of vitamin E. The highest macrophage oxidative burst activity, measured by chemiluminescence, was found in fish receiving both vitamins at high levels. In the disease resistance experiments, the best survival rates in trout infected with viral haemorrhagic septicaemia virus were achieved with diets containing both vitamins at a high level, or at least one at a high and the other at a low level. Highest mortalities in fish infected with Yersinia ruckeri occurred in trout fed double‐deficient or double low diets. The best survival of fish exposed to Ichthyophthirius multifiliis was achieved with diets high in one and low in the other, or high in both vitamins. However, differences were not statistically significant in the parasite experiment.
The effects of hydrogen peroxide treatment on different life‐cycle stages of the salmon louse, Lepeophtheirus salmonis (Krøyer 1837)
Authors: McAndrew K J , Sommerville C , Wootten R , Bron J E 
Published: March 2003

AbstractThe effects of hydrogen peroxide administered at a concentration of 1500 ppm for 20 min at 7.5 °C on different life‐cycle stages of Lepeophtheirus salmonis were examined experimentally. The mobile adult and pre‐adult stages of L. salmonis readily reattached to Atlantic salmon after hydrogen peroxide treatment. Adult female lice, but not adult males or pre‐adults, reattached in significantly lower numbers than untreated controls. Survival of early chalimus stages (I and II) was not affected by hydrogen peroxide treatment, but their subsequent development to chalimus III and IV was delayed compared with untreated controls. Nauplii and copepodid larvae of L. salmonis were almost all dead by 1 hour post‐treatment. A very few copepodids survived 24 h post‐treatment. Egg strings of L. salmonis at an early stage of development failed to hatch after hydrogen peroxide treatment, but those with pigmented eggs did hatch, although in significantly reduced numbers. Treated egg strings did produce viable copepodids, although in significantly reduced numbers compared with controls.
Use of microencapsulated fish oil as a means of increasing n‐3 polyunsaturated fatty acid intake
Authors: Higgins S. , Carroll Y. L. , O'Brien N. M. , Morrissey P. A. 
Published: March 2003

Summary Background: The successful incorporation of fish oil into foods may provide a means of increasing intakes of n‐3 polyunsaturated fatty acids (n‐3 PUFA). The aim of the present study was to evaluate the bioavailability of n‐3 PUFA in microencapsulatd fish oil compared with a fish oil capsule. Methods: Twenty‐eight healthy volunteers were recruited to take part in this randomized controlled trial. Volunteers were supplemented with 0.9 g n‐3 PUFA daily for 4 weeks, delivered either as microencapsulated fish oil in a milkshake or as a fish oil capsule. Plasma fatty acid composition and plasma total cholesterol levels were measured at baseline and after supplementation. In addition, volunteers completed a questionnaire on fish consumption, use of supplements and exercise. Results: Responses to the questionnaire indicated that the males who took part in this study took more physical exercise, consumed less fish and were less likely than the females to take supplements. Plasma n‐3 PUFA concentrations were raised significantly and by a similar level by both fish oil supplements. Furthermore, no significant difference was observed in plasma n‐3 PUFA concentrations following supplementation with either form of fish oil. Plasma total cholesterol levels were not significantly altered by n‐3 PUFA supplementation in either group. The results of this study indicated that there was no difference in the bioavailability of n‐3 PUFA given as microencapsulated fish oil compared with n‐3 PUFA delivered as a fish oil capsule. Fortification of foodstuffs with microencapsulated fish oil therefore offers the potential to increase intakes of n‐3 PUFA in line with current recommendations.
Consumption of soup and nutritional intake in French adults: consequences for nutritional status
Authors: Bertrais S. , Galan P. , Renault N. , Zarebska M. , Preziosi P. , Hercberg S. 
Published: March 2003

AimThe impact of soup consumption on nutrient intake and nutritional indicators was assessed in adults who consumed soup compared to those who did not or who were occasional eaters.MethodsData were obtained for 2188 men and 2849 women living in France and participating in the SU.VI.MAX cohort, who reported twelve 24‐h dietary records during a 2‐year follow‐up period (60 444 records). Subjects were divided into three groups: (1) those who ate soup 0–2 days or less out of 6 days were classified as occasional or non‐consumers; (2) those who consumed soup 3–4 days out of 6 were defined as regular consumers; (3) those who consumed soup 5–6 days out of 6 were defined as heavy consumers.ResultsSeven per cent of women and 9% of men were heavy consumers of soup. Respectively, 46 and 42% were regular, and 47 and 49% were occasional or non‐consumers. Mean energy intake was lower in heavy consumers than in occasional or non‐consumers, but the difference was statistically significant only in women. In men and women, heavy consumers of soup had significantly higher intakes of carbohydrates than occasional and non‐consumers (245 g J−1 vs. 227 g J−1 in men; 186 g J−1 vs. 176 g J−1 in women) and lower lipid intakes (97 g J−1 vs. 102 g J−1 in men; 80 g J−1 vs. 75 g J−1 in women). Soup consumers presented lower energy intake at dinner than light or non‐consumers. In soup consumers, breakfast and lunch contained greater amounts of carbohydrates, lipids and proteins, but dinner contained significantly smaller amounts of lipids and proteins.A higher frequency of BMI > 27 kg m−2 was found in occasional and non‐soup consumers; conversely a higher frequency of BMI between 23 and 27 kg m−2 was found in regular consumers of soup and a higher frequency of BMI < 23 kg m−2 in heavy consumers. For women, an association was found between occasional or non‐ consumers and BMI > 25 kg m−2 and between heavy consumers and BMI < 22 kg m−2. Likewise an association was found in men only between heavy consumption of soup and lower value of serum cholesterol.ConclusionThe present data suggest that the consumption of soups contributes to a balanced diet. Consumption of soup may be beneficial for a healthy nutritional status in the overall population.
Dietetic guidelines: diet in secondary prevention of cardiovascular disease
Authors: Hooper L. 
Published: March 2003

AimTo produce dietetic guidelines summarizing the systematic review evidence on dietary advice for secondary prevention of cardiovascular disease.MethodsThe Cochrane Library,MEDLINEandEMBASEwere comprehensively searched for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomised controlled trials relating to diet and secondary prevention of cardiovascular disease. Two members of the UK Heart Health and Thoracic Dietitians Group critically appraised each review. The quality and results of each review were discussed and summarized in a whole group meeting. The guidelines were trialled in seven dietetic departments and modified where necessary.ResultsProviding evidence‐based dietary information (including increasing omega‐3 fat plus fruit and vegetable intake) to all people after myocardial infarction will save more lives than concentrating dietary advice on those in need of weight loss or lipid lowering. The practice of prioritizing dietetic time to those with raised lipids is out of date since the advent of statin therapy.ConclusionThere is good systematic review evidence that dietary advice to those with cardiovascular disease can reduce mortality and morbidity as well as modify risk factors. Dietary advice that does this most effectively should be prioritized.