bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of dwarf shrubs to neighbour removal and nutrient addition and their influence on community structure in a subalpine heath
Authors: Gerdol Renato , Brancaleoni Lisa , Menghini Marisa , Marchesini Roberta 
Published: March 2003

Summary 1 A 3‐year experiment involving nutrient addition and removal of one of two coexisting dwarf shrub species was conducted in two community types in a subalpine heathland on the northern Apennines (Italy). Vaccinium uliginosum occurred at all sites but was associated with the deciduous Vaccinium myrtillus at more sheltered nutrient‐rich sites (HV community), and with the evergreen Empetrum hermaphroditum where the habitat was poorer and more exposed (EV community). Length of current‐year shoots and fruit production of each species were determined in each of the 3 years, and standing crop at the beginning and end of the experiment. 2 The length of current‐year shoots of both deciduous species, but not of the evergreen, varied considerably between years, presumably due to varying temperatures at the beginning of the three growing seasons. Fruit production also varied. 3 Fertilization promoted an increase in the length of V. uliginosum shoots at the HV community but not at the EV community. The removal of V. uliginosum enhanced shoot elongation in V. myrtillus (HV community) but reduced shoot elongation in E. hermaphroditum (EV community). Neighbour removal did not affect shoot length of V. uliginosum at either community. There were few treatment effects on fruiting of these clonal species. 4 The standing crop in untreated stands did not change during the experimental period. Changes in shoot length resulting from environmental manipulations were not accompanied by consistent variation in the standing crop of any species. Standing crop increased only for V. myrtillus after removing V. uliginosum at the HV community (same direction as shoot length). The standing crop of E. hermaphroditum did not change after removing V. uliginosum at the EV community, although shoot length was significantly reduced. The standing crop of V. uliginosum was unaffected by neighbour removal and was decreased by nutrient addition at both communities. 5 None of the shrubs appeared able to utilize more abundant resources to increase above‐ground biomass. However, increased shoot length in nutrient‐rich habitats gave V. uliginosum a superior ability to capture light compared with V. myrtillus, the latter being more successful when the coexisting competitively superior species was removed. This would support Grime’s theory, indicating that competition becomes more important as soil resource levels increase. Positive interactions appeared to play a role in the more extreme habitat, where E. hermaphroditum normally benefited from the shelter of the V. uliginosum canopy but was able to adapt its architecture when exposed.
Livestock grazing in subtropical pastures: steps in the analysis of attribute response and plant functional types
Authors: McIntyre S. , Lavorel Sandra 
Published: March 2003

SummaryIn order to investigate the use of plant functional types as an alternative to floristic descriptions of response to grazing, we analysed plant communities from a cattle grazing experiment conducted in grassy eucalypt woodland in subtropical Queensland, Australia. The two variables analysed (landscape position and stocking rate) accounted for similar proportions of variation in the vegetation ground layer, although forbs were more sensitive to slope position and perennial grasses were more sensitive to stocking rate.As grazing pressure increased, perennial grasses declined, while the relative proportion of forbs and annual grasses increased. Detailed functional group analyses were conducted for the perennial grass and forb life‐forms. Annual grasses were represented by only two species, preventing identification of functional types within this life‐form.We conducted a five‐step analysis for both perennial grasses and forbs as follows: (i) defining grazing‐related species response groups; (ii) defining species groups based on natural attribute correlations; (iii) identifying attributes that changed significantly with grazing; (iv) identifying syndromes by relating (ii) and (iii); (v) describing functional types from (iii) and (iv), and assessing them against actual species response.Eight grass and eight forb functional types were identified. Of the taxa that had an observed response to grazing, 54% of the grass taxa and 57% of the forb taxa corresponded to one of these functional types in terms of meeting both grazing response and trait criteria. The five‐stage analysis provided a comprehensive but complex approach to functional type identification.The functional types identified can be summarized as follows. Low levels of grazing were associated with more medium‐sized, moderately leafy perennial grasses with wind‐dispersed or adhesive seeds, and more erect or twining forbs with large to medium sized seeds. High levels of grazing were associated with: more annual grasses; low‐growing leafy perennial grasses with small seeds having no dispersal appendages; mat‐forming large‐seeded forbs; and low‐growing, scrambling, small‐seeded forbs.
Plant responses to competition and soil origin across a prairie–forest boundary
Authors: Peltzer Duane A. 
Published: March 2003

Summary

The distribution of different plant growth‐forms may be caused by interactions among plants. Previous studies show that prairie and forest vegetation have different competitive effects and also influence both resource availability and soil community structure.
I used a field experiment to distinguish between short‐term competitive effects and the long‐term effects of vegetation on soils. Soil cores were reciprocally transplanted between prairie and forest sites. Seedlings of a grass (Boutelouagracilis) and a shrub (Elaeagnuscommutata) were planted into these cores and grown with or without neighbours.
Soil origin did not significantly alter the survival, growth or responses to competition of either transplant species. Bouteloua and Elaeagnus growth was suppressed by neighbours to about the same extent in prairie, but only Bouteloua growth was suppressed in forest, resulting in a significant interaction between environment and competition. All except one of the interactions involving soil origin were not significant, suggesting that plant‐soil feedbacks did not modify the effects of competition or environment.
The results suggest that environment and competition have much larger influences on the performance of juvenile plants in the field than does soil origin. Further work is needed to determine the relative importance of resource competition and soil community effects on plant performance among species and study systems.
Selectivity and functional diversity in arbuscular mycorrhizas of co‐occurring fungi and plants from a temperate deciduous woodland
Authors: Helgason T. , Merryweather J. W. , Denison J. , Wilson P. , Young J. P. W. , Fitter A. H. 
Published: March 2003

Summary 1
The arbuscular mycorrhizal (AM) fungi colonizing plants at a woodland site in North Yorkshire (UK) have been characterized from the roots of five plant species (Rubus fruticosus agg. L., Epilobium angustifolium L., Acer pseudoplatanus L., Ajuga reptans L. and Glechoma hederacea L.), and identified using small‐subunit rRNA (SSUrRNA) gene amplification and sequencing. 2 Interactions between five plant species from the site and four co‐occurring glomalean fungi were investigated in artificial one‐to‐one AM symbioses. Three of the fungi were isolated from the site; the fourth was a culture genetically similar to a taxon found at the site. Phosphorus uptake and growth responses were compared with non‐mycorrhizal controls. 3 Individual fungi colonized each plant with different spatial distribution and intensity. Some did not colonize at all, indicating incompatibility under the conditions used in the experiments. 4

Glomus hoi consistently occupied a large proportion of root systems and out‐performed the other fungi, improving P uptake and enhancing the growth of four out of the five plant species. Only G. hoi colonized and increased P uptake in Acer pseudoplatanus, the host plant with which it associates almost exclusively under field conditions. Colonization of all plant species by Scutellospora dipurpurescens was sparse, and beneficial to only one of the host plants (Teucrium scorodonia). Archaeospora trappei and Glomus sp. UY1225 had variable effects on the host plants, conferring a range of P uptake and growth benefits on Lysimachia nummularia and T. scorodonia, increasing P uptake whilst not affecting biomass in Ajuga reptans and Glechoma hederacea, and failing to form mycorrhizas with A. pseudoplatanus. 5 These experimental mycorrhizas show that root colonization, symbiont compatibility and plant performance vary with each fungus–plant combination, even when the plants and fungi naturally co‐exist. 6 We provide evidence of physical and functional selectivity in AM. The small number of described AM fungal species (154) has been ascribed to their supposed lack of host specificity, but if the selectivity we have observed is the general rule, then we may predict that many more, probably hard‐to‐culture glomalean species await discovery, or that members of species as currently perceived may be physiologically or functionally distinct.
Colonization dynamics of the clonal moss Hylocomium splendens on islands in a Baltic land uplift area: reproduction, genet distribution and genetic variation
Authors: Cronberg Nils 
Published: March 2003

Summary

Islands representing four stage classes, dated by their height above sea level, in a Baltic land uplift area were used to study genet level dynamics during colonization of the clonal moss Hylocomium splendens. Allozyme electrophoresis involving 10 polymorphic loci enabled accurate identification of 103 haplotypes from a sample of 694 shoots collected along transects across 10 islands.
The populations consisted initially of scattered colonies with single clones. The number of clones, and the tendency of colonies to be multiclonal, increased significantly with increasing age of islands, whilst their mean size decreased significantly. In the Skeppsvik Archipelago, H. splendens thus shows repeated recruitment.
The percentage male or female fertile shoots relative to sterile shoots was positively correlated with age of the islands. The sex ratios were skewed during early colonization.
Spore capsules were found only in the oldest succession stage‐classes. This can be explained by a greater chance for fertile males and females to grow within the fertilization range, which is limited to a few centimetres.
Genetic variation was accumulating with increasing population age. Correlations were stronger for mean number of alleles per locus (A) than for gene diversity (HS).
No isolation by distance was detected among populations, indicating efficient and essentially random gene flow, probably occurring via wind‐dispersed spores.
A recruitment strategy for cluster randomized trials in secondary care settings
Authors: Walker Anne E. , Campbell Marion K. , Grimshaw Jeremy M. , group the Tempest 
Published: March 2003

AbstractTrials of educational or organizational interventions to change clinical practice require cluster randomization, that is, randomization of units such as hospitals or clinical teams rather than individual patients. Cluster randomization is relatively novel in health care settings and raises new methodological challenges, in particular: are units willing to be randomized at an organizational level; and, what procedures should be followed to successfully enrol all of the clinicians in a unit rather than individual clinicians as in conventional multicentre trials. This is particularly problematic for trials of large units such as hospitals. The aim of this study was to develop and partially evaluate a strategy to recruit acute, secondary care NHS hospitals in the UK into cluster randomized trials. Literature search and interviews with senior staff in acute hospitals and relevant national organizations were used to develop a recruitment strategy. The strategy was evaluated by inviting 32 randomly selected clinical directorates to participate in a trial feasibility study. A seven step recruitment strategy was developed: (1) Identify stakeholders and gatekeepers; (2) Inform stakeholders and gatekeepers; (3) Approach gatekeepers; (4) Local negotiation; (5) Conduct the research; (6) Feedback to gatekeepers; (7) Feedback to stakeholders. Key problems were the possibility of multiple gatekeepers and identification of all possible stakeholders in varying organizational structures. The strategy was effective in two respects. First, 32 (100%) of the directorates approached agreed to participate. Second, baseline data collection was successfully achieved in all of the directorates. However, the strategy is costly in terms of time and resources.We conclude that NHS trusts are willing to participate in cluster randomized trials. This recruitment strategy is successful and could be widely adopted, but realistic time and financial cost estimates are required at the planning stage.
In vitro and in vivo effects of rabbit anti‐thymocyte serum on circulating leucocytes and production of complement fixing antibodies in thymectomized Oncorhynchus mykiss (Walbaum) infected with Cryptobia salmositica Katz 1951
Authors: Feng  , Woo  
Published: March 2003

AbstractRabbit anti‐thymocyte serum (RATS) against thymocytes of rainbow trout was toxic to leucocytes from intact and thymectomized rainbow trout at 10 °C under in vitro conditions. The total number of leucocytes decreased significantly in 24 h after RATS was injected intraperitoneally into intact rainbow trout, but the number returned to pre‐injection level within 1 week. RATS destroyed a lower percentage of leucocytes in thymectomized fish than in intact fish under both in vitro and in vivo conditions and the recovery in the number of leucocytes was slower in thymectomized fish. The parasitaemia, packed cell volume and production of complement fixing antibody in thymectomized and intact fish (injected with RATS before Cryptobia salmositica infection) were not significantly different from control fish (not injected with RATS), and they both acquired protective immunity against cryptobiosis on recovery. This indicates that RATS is not cytotoxic to B‐like cells in the lymphoid tissue which produce complement fixing antibody against C. salmositica and that the protective antigen in C. salmositica seems to be thymus‐independent.
Process evaluation of a research workshop and follow‐up support to help practitioners from 13 weight management projects to carry out evaluations
Authors: Rayner  , Ziebland  
Published: March 2003

Background: In October 1997 the Department of Health agreed to fund evaluations of 13 weight management projects and offer research training and support for the successful applicants. Aims: To help the projects develop focused and relevant research questions for their evaluations; to encourage the use of appropriate methods to answer these research questions; and to help the projects set realistic timetables and budgets. A 2‐day seminar was held in Oxford and follow up support was available from the seminar tutors. Methods: A process evaluation was conducted. Semistructured telephone interviews with all seminar participants took place 2 weeks after the seminar and again after the completion of the evaluation reports. An independent assessor compared the original proposals with the final reports. Results: Eleven projects sent representatives to the seminar. All of the 11 projects that sent representatives to the seminar had subsequent contact with the tutors and submitted final reports in February 1998. The independent assessor concluded that for six projects there was improvement in the research questions and methods which were used and no change for the other five. Conclusions: Recommendations include amending the selection procedure for funding evaluations and specific suggestions to improve the organization and content of the research training seminar and follow‐up support.
What are the characteristics of overweight and obese patients who achieve weight loss and what factors are most helpful? A quantitative and qualitative study of patients and interventions in a rural general practice
Authors: Roberts  , Ashley  
Published: March 2003

Introduction and aims: Of the modifiable cardiovascular risk factors obesity remains the most difficult to influence. Sustained weight reduction is a rare outcome in general practice. A minority of patients do, however, succeed. This study attempts to identify characteristics of successful weight losers (SWL) in primary care and to identify other factors associated with success. Method: The study was in two parts: (1) a case‐control review of the overweight and obese, using the existing data on cardiovascular risk factors in the practice collected over 8 years. The demographic and clinical characteristics of those achieving and maintaining 10% weight loss for at least 3 months were compared with the unsuccessful controls (UWL); (2) a qualitative study of the small group of successful weight losers, employing semistructured interviews in each patient’s home, looking for patient’s ideas on what led to success. Results: One hundred and ninety‐eight initially overweight (BMI > 25 kg/m2) had follow up weight measurements recorded; 18 (9%) were SWLs. Success was associated with adverse coronary heart disease (CHD) risk profile, particularly with initial and follow‐up cholesterol levels where the association was highly significant (P < 0.0001). The qualitative study suggested a different profile of factors operating in initiation vs. maintenance of weight loss (predominant health related anxiety, in initiation, and enhanced self‐image, in maintenance). Conclusions: SWLs are more likely to have modifiable CHD risk factors than UWLs. Some SWLs seem to make a global improvement in modifiable risk factors when they lose weight. Anxiety about health, either from health professional advice or screening, or from life events, is the commonest reason for initiating successful weight loss. Doctor and nurse advice was the principal initiating factor in several instances. Self‐generated positive feelings about weight loss are the commonest factors in sustaining weight loss, followed by support from family and friends and support and follow‐up by the Primary Health Care Teams.
A20. Health and social factors affecting the food choices and nutritional intake of elderly people with restricted mobility
Authors: Wylie C. 
Published: March 2003

Background Little is known about the magnitude of health and social factors which affect the food choices and nutritional intake of elderly people with restricted mobility.Aims The aim of this study was to investigate food choices in this population group.Methods Semi structured taped interviews were used to capture expressions used in the indentification of health and social factors which affect food choices and nutritional intake of 12 female subjects and three male subjects over the age of 65 (age range 67–91 years, mean 80.6 years) living in the community with restricted mobility. Twenty‐four hour recall method of dietary assessment was undertaken in order to establish their dietary intake and meal patterns.Results Intakes of fluid, fruit and vegetables and non starch polysaccharide were found to be inadequate. In addition, there was an infrequent consumption of cooked meals. Health and social factors which affect the food choices and nutritional intake in this group of the elderly population were identified as being inadequate money, inadequate food storage facilities, physical disabilities affecting food preparation, poor access to shops, difficulties in shopping, type of cooking facilities, loneliness and bereavements.The dietary intake and food choices of the elderly population have often been shown to be affected by a combination of health, social and psychological factors which include living alone, being house bound, having swallowing difficulties and suffering from depression ( Davies and Knutson, 1991). The findings of this study further support such findings and highlighted three areas that affected the nutritional intake of a group of elderly people with restricted mobility. These were social (loneliness, bereavement), economic (budget for food, access to Social services) and physical (difficulties in shopping, preparing and cooking foods).Conclusions It was concluded that elderly people living in the community with restricted mobility may be unable to consume an optimum nutritional intake due to the health and social factors were identified by this study which affect their food choices and nutritional intake.
Availability of micronutrients from dried, encapsulated fruit and vegetable preparations: a study in healthy volunteers
Authors: Leeds A. R. , Ferris E. A. E. , Staley J. , Ayesh R. , Ross F. 
Published: March 2003

Background High levels of consumption of fruit and vegetables, which contain antioxidant nutrients including vitamins C and E as well as β‐carotene, are associated with reduced rates of atherosclerotic arterial disease and some cancers. Low plasma levels of these micronutrients are associated with an increased risk of chronic degenerative disease. While increasing consumption of fruit and vegetables would be desirable, many factors including cost tend to prevent this. Preparations of the active components of fruit and vegetables encapsulated to achieve convenience may contribute to solving this problem.Aims This study was designed to determine whether two such supplements prepared from dehydrated fruit and vegetable extracts (Juice Plus+™ Fruit and Juice Plus+™ Vegetable) would result in elevation in blood concentrations of antioxidants to levels associated with lower disease risk.Methods Sixteen healthy subjects (eight male, eight female, aged 18–52 years) were screened to exclude disease and to exclude any individual with a serum β‐carotene below 0.05 µmol L–1, and were divided into two groups of eight, each to consume either the fruit or vegetable preparation. Four days before administration of the capsules the subjects commenced a low β‐carotene diet. Venous blood samples for determination of vitamin C, vitamin E (as α‐tocopherol) and β‐carotene were taken in the morning on days 0, 2, 4, 6 and 7, after a 10‐h fast. Two capsules of either the fruit preparation (containing vitamin E 30 mg, vitamin C 150 mg and β‐carotene 6 mg) or vegetable preparation (containing vitamin E 30 mg, vitamin C 50 mg and β‐carotene 9 mg) were taken on days 0–6 inclusive with a 610‐kcal breakfast (47% energy from fat).Results Serum β‐carotene levels rose significantly by 0.56 µmol L–1 and 0.54 µmol L–1 after fruit and vegetable preparations, respectively, by day 7, vitamin E levels rose significantly by 3.1 µmol L–1 after the fruit preparation but not after the vegetable preparation and vitamin C rose significantly from 28 to 62 µmol L–1, and from 32 to 50 µmol L–1 after the fruit and vegetable preparations, respectively. Plasma malondialdehyde, regarded as a general indicator of peroxidation, fell significantly by 19 × 10–5 µmol L–1 (about a 40% reduction) in both treatment groups.Conclusions These results indicate that concentrated extracts of fruits and vegetables can raise blood antioxidant levels into the ranges associated with reduced risk of disease and that this reduces the concentration of a general measure of lipid peroxidation. Further studies, especially in those with disease characterized by increased oxidative stress, are indicated.