bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of post‐fire seedling establishment between scrub communities in mediterranean and non‐mediterranean climate ecosystems
Authors: Carrington M.E. , Keeley J. E. 
Published: March 2003

Summary1 Both fire regimes and the conditions under which fires occur vary widely. Abiotic conditions (such as climate) in combination with fire season, frequency and intensity could influence vegetation responses to fire. A variety of adaptations facilitate post‐fire recruitment in mediterranean climate ecosystems, but responses of other communities are less well known. We evaluated the importance of climate by comparing sites with mediterranean and subtropical climates.2 We used paired burned and mature sites in chamise chaparral, mixed chaparral and coastal sage scrub (California), and rosemary scrub, sand pine scrub and sandhill (Florida), to test whether (i) patterns of pre‐fire and post‐fire seedling recruitment are more similar between communities within a region than between regions, and (ii) post‐fire stimulation of seedling establishment is greater in regions with marked fire‐induced contrasts in abiotic site characteristics.3 Post‐fire seedling densities were more similar among sites within climatic regions than between regions. Both seedling densities and proportions of species represented by seedlings after fires were generally higher in California.4 The only site characteristic showing a pre‐fire–post‐fire contrast was percentage open canopy, and the effect was greater in California than in Florida. Soil properties were unaffected by fire.5 Mediterranean climate ecosystems in other regions have nutrient‐poor soils similar to our subtropical Florida sites, but show post‐fire seedling recruitment patterns more similar to the nutrient‐rich sites in California. Climate therefore appears to play a more major role than soil characteristics.
Detection of delayed density dependence in an orchid population
Authors: Gillman M. P. , Dodd M. 
Published: March 2003

Summary 1 Annual censuses of Orchis morio (green‐winged orchid) flowering spikes have been taken over a 27‐year period in a replicated factorial experiment on the effects of fertilizer application. Census data, combined by block or treatment, were used in time–series analyses to test for density dependence. 2 Partial autocorrelation functions revealed the importance of positive correlations at lag 1 and negative correlations at lag 5. Stepwise multiple regressions provided evidence of delayed density dependence, again with a delay of about 5 years, with no evidence of direct (first‐order) density dependence. 3 First‐order autocorrelations and delayed density dependence were considered in the light of the known stage structure and generation time of the plant and the possibility of density dependence at different points in the life history. 4 Model structure affects the detection of density dependence, increasing the propensity for type I errors.
Effects of low and high nutrients on the competitive hierarchy of 26 shoreline plants
Authors: Keddy Paul , Gaudet Connie , Fraser Lauchlan H. 
Published: March 2003

Summary 1 We tested the hypothesis that competitive hierarchies are invariant with respect to changing nutrient supply. 2 The competitive performance of 26 shoreline plant species was determined experimentally as the relative ability to suppress the growth of a common indicator (phytometer) species, Penthorum sedoides. Each species was grown with the phytometer under each of two nutrient treatments created with different concentrations of a modified Hoagland’s solution (n = 5 replicates per species/treatment), for two growing seasons. 3 Although shifts in ranking of relative competitive performance were apparent between nutrient levels, competitive performance under high and low nutrient conditions was significantly correlated in both year 1 (r = 0.65) and year 2 (r = 0.76), when all species were considered. 4 At the broad community scale, the outcome of competitive interactions thus appears to be relatively predictable and independent of the environment, and therefore provides a useful tool for exploring and understanding community pattern. These results cannot address questions related to the outcome of competitive interactions between similar species or the effects of fine‐scale pattern.
Below‐ground ectomycorrhizal community structure in a recently burned bishop pine forest
Authors: Grogan P. , Baar J. , Bruns T.D. 
Published: March 2003

Summary1 The effects of wildfire ash on ectomycorrhizal (EM) associations were investigated by sampling bishop pine (Pinus muricata,D. Don) seedlings from control and ash‐removed plots 1.5 years after a severe fire in a northern CalifornianP. muricataforest. The below‐ground community composition of EM at the site was characterized using molecular techniques (PCR‐RFLP and nucleotide sequencing).2 A total of 30 fungal taxa were observed, many of which differed in their distribution between treatment and control seedlings. However, most of the taxa that were distinctive to either treatment or control seedlings occurred only once across the site, precluding statistical detection of potential ash effects on EM community composition. There were no significant effects of ash removal on plot‐level mycorrhizal community richness or diversity, and there were no distinct treatment‐related clusters in a principal components analysis.3 Analysis of the combined data indicated that numbers of fungal taxa per seedling, numbers of successive root depth increments colonized by the same taxon, and distances to neighbouring seedlings colonized by the same taxon, were randomly distributed across the site for the majority of mycorrhizal fungi. These distributional patterns suggest that the post‐fire mycorrhizal community structure onP. muricataarose primarily from successful colonization by randomly distributed point‐source fungal inocula within the upper mineral soil layer of the forest floor.4 By comparison with pre‐fire studies from similarP. muricatasites nearby, our data indicate that severe wildfire disturbance resulted in marked changes in mycorrhizal community composition, and a sharp increase in the relative biomass of ascomycetous fungi.
Nutritional constraints onSphagnum‐growth and potential decay in northern peatlands
Authors: Aerts Rien , Wallén Bo , Malmer Nils , De Caluwe Hannie 
Published: March 2003

SummaryIn a 4‐year fertilization experiment we studied the effects of increased nitrogen (N) or phosphorus (P) supply on productivity and potential decay in the acrotelm ofSphagnum‐dominated Swedish peatlands at northern (low atmospheric N input: low‐N site) and southern (high atmospheric N input: high‐N site) sites. During the experimental period, there was a severe summer drought at the high‐N site which led to strong limitations onSphagnumgrowth, especially in the fertilized treatments. There were no significant effects of the nutrient treatments on cumulative length growth and productivity at either site. There were, however, significant effects of site and nutrient treatment on nutritional variables of theSphagnumspecies. Nitrogen concentration in living capitula was lower, but P concentration was higher at the low‐N site than at the high‐N site. However, at both sites N and P concentration in the living capitula showed only minor responses to the nutrient additions. Litter chemistry variables differed significantly among sites and treatments.Sphagnumlitter had lower N concentration, higher P concentration, a higher C : N ratio, a lower C : P ratio and a lower N : P ratio at the low‐N site. Litter chemistry was significantly affected by the nutrient treatments only at the high‐N site, where litter P concentrations increased significantly in the P‐fertilized treatment, whereas C : P and N : P ratios showed a significant reduction. Although potential rates of decay ofSphagnumlitter were higher at the high‐N site than at the low‐N site, they were not significantly affected by nutrient additions. Potential decay rates did, however, show significant relations with all the litter chemistry variables we had determined. An increase in nitrogen input toSphagnum‐dominated bogs appears to lead to higher N concentrations in litter and, as a result of dilution, to lower P concentrations. This change in litter chemistry leads to a higher potential decay rate of the litter and this may seriously affect the carbon balance in the acrotelm of these systems. Our results also show that carbon balance characteristics ofSphagnumbogs can be strongly affected by unpredictable extreme climatic conditions. This suggests that the occurrence and consequences of these events need more attention when long‐term responses of ecosystems to global change are studied.
Forest herb colonization of postagricultural forests in central New York State, USA
Authors: Singleton Rhine , Gardescu Sana , Marks P. L. , Geber Monica A. 
Published: March 2003

Summary The recovery of forest vegetation following abandonment of agriculture was followed by surveying forest herbs in central New York State at 25 sites where postagricultural forest occurred directly adjacent to old‐woods (forest that has never been ploughed). The abundance, richness and diversity of 50 forest herbs were on average lower in postagricultural forests than in old‐woods. Thirty of 39 forest herbs that were found in at least four stands were less frequent (number of plots present out of 60) in postagricultural forests than in old‐woods. Three species (Aster divaricatus,Dryopteris intermediaandPolystichum acrostichoides) had significantly higher frequency in old‐woods, while none was significantly more common in postagricultural forests. Although differences among species in their frequency in the two forest types were not strongly related to dispersal mode, species with rapid clonal expansion were significantly more frequent in postagricultural stands. Several species that were less frequent in postagricultural forests than in old‐woods showed decreases in density in postagricultural forests with increasing distance from the adjacent old‐woods.
Monitoring the care of lung cancer patients: linking audit and care pathways
Authors: Kaltenthaler E. , McDonnell A. , Tech J. Peters B. 
Published: March 2003

AbstractClinical audit plays an important role in monitoring the provision of care for patients whatever their condition. Care pathways define the steps and expected course of events in the care of patients with a specific clinical problem over a set time scale. This paper describes a study undertaken in a multisite cancer unit to develop a tool for monitoring the progress of lung cancer patients through a care pathway and auditing key standards within the pathway. Important issues associated with the development of this tool are highlighted. The process of developing this tool involved the following steps: a review of the literature dealing with the management of lung cancer patients; interviews with key personnel in primary, secondary, tertiary and palliative care; development of a paper‐based series of forms representing key steps in the patient’s care pathway; 3‐month trial of the paper‐based tool; analysis of completion rates and interviews with form users to evaluate effectiveness; and recommendations for creating an electronic record using the experience and lessons learned from the paper version. The paper forms developed through this multistage process were found to be acceptable to users and have the potential to provide accurate information at key points for audit throughout the patient’s time within the health‐care system for their lung cancer condition. The flexibility of this methodology allows it to be adapted readily to a variety of clinical situations and conditions.
National sentinel clinical audit of evidence‐based prescribing for older people: methodology and development
Authors: Grant R. L. , Batty G. M. , Aggarwal R. , Lowe D. , Potter J. M. , Pearson M. G. , Oborne A. , Jackson S. H. D. 
Published: March 2003

AbstractRationale, aims and objectives This national clinical audit aimed
to develop and implement a methodology to assess the appropriateness of prescribing
for patients over the age of 65 in hospitals, general practice and nursing homes.
Methods Organizations providing health care in the National Health
Service in these three sectors were recruited into multi‐disciplinary and inter‐organizational
local coalition teams. Prescription data and relevant clinical data were collected
electronically on a customized database. The appropriateness of prescribing for specific
conditions among the patients sampled was assessed by simple computerized algorithms,
and users were provided with feedback to stimulate discussion and change. Use of
the software tool was demonstrated to be feasible and its data reliable. Participants
were re‐audited, after a period of nationally guided and locally driven intervention,
to evaluate levels of change. Local efforts to stimulate change and barriers to change
were collected qualitatively. Results and conclusions The investigation revealed encouraging results and demonstrated the ability of audit to improve the quality of clinical services in given circumstances, although a multiplicity of questions relating to cost and methodology remain to be addressed.
Prescribing pattern of antihypertensive drugs by family physicians and general practitioners in the primary care setting in Bahrain
Authors: Sequeira Reginald P. , Jassim Khalid A. , Damanhori Awatif H. H. , Mathur Vijay S. 
Published: March 2003

AbstractThe aim was to determine whether there are differences among family physicians (FPs) and general practitioners (GPs) in terms of their preference for different classes of antihypertensives, either alone or in combinations, in uncomplicated cases of hypertension and to determine the extent of adherence to WHO/ISH guidelines. We have analysed prescribing of antihypertensives by qualified family physicians (FPs) (n=77) and compared this with that of general practitioners (GPs) (n =41) by auditing 1791 prescriptions of FPs and 914 prescriptions of GPs, issued to patients with uncomplicated hypertension, at 15 out of 20 health centres in Bahrain. The choice of antihypertensive(s) by FPs and GPs was comparable and conformed with the WHO/ISH guidelines as regards preference for: (i) β‐blockers, angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers (CCBs) as monotherapy; (ii) two‐drug combinations (diuretic–β‐blocker; β‐blocker–CCB); (iii) three‐drug combinations (diuretic–β‐blocker–CCB; diuretic–β‐blocker–ACE inhibitor; β‐blocker– ACE inhibitor–CCBs), and (iv) choice of drug used for the elderly either alone (CCBs) or as combinations (diuretic–β‐blocker; β‐blocker–CCB and diuretic–β‐blocker–ACE inhibitor; diuretic–β‐blocker–CCB). In several instances prescribing by both FPs and GPs was not in accordance with the WHO/ISH guidelines: reluctance to prescribe diuretics as monotherapy; use of suboptimal combinations (β‐blocker–ACE inhibitor); and extensive use of β‐blockers and irrational use of immediate‐release nifedipine in elderly. A statistically significant prescribing difference between FPs and GPs was evident in the following: β‐blockers as monotherapy (P =0.01), diuretic–CCB (P=0.046), and diuretic–CCB–methyldopa (P=0.01) combination, and immediate‐release nifedipine monotherapy in the elderly (P=0.027), were prescribed more often by the GPs. However, β‐blocker–ACE inhibitor–CCB combination was more often prescribed by FPs (P=0.046). Remarkable differences in prescribing pattern of antihypertensives between the FPs and GPs were evident. Although the general pattern supported a superior prescribing profile of the FPs as expected, there is a need for improved prescribing by both GPs and FPs. Educational programmes, both graduate and residency training, and continuing professional education, should specifically address these deficiencies in order to assure quality primary health care.
Hafnia alvei as an opportunistic pathogen causing mortality in brown trout, Salmo trutta L.
Authors: Rodríguez L. A. , Gallardo C. S. , Acosta F. , Nieto T. P. , Acosta B. , Real F. 
Published: March 2003

AbstractStrains of Hafnia alvei caused mortalities in brown trout, Salmo trutta L., following intraperitoneal injection with LD50 values ranging between 1.3 × 104 and 2.5 × 107 bacteria fish−−1. These values are considered to represent a high to moderate degree of virulence. Virulent strains were isolated from non‐fish sources. Fish surviving the LD50 values continued to harbour the organism in the kidney, suggesting the establishment of a carrier state.
Epizootics in farm‐raised channel catfish, Ictalurus punctatus (Rafinesque), caused by the enteric redmouth bacterium Yersinia ruckeri
Authors: Danley M L. , Goodwin A E. , Killian H S. 
Published: March 2003

AbstractIn the winters of 1995 and 1996, unusual disease outbreaks occurred on two separate channel catfish farms in Arkansas, USA. Affected fish exhibited extraordinary haemorrhaged rings around the eyes and raised haemorrhaged areas overlying the frontal foramens. Other signs included abnormal swimming, lethargy, loss of equilibrium, and exophthalmia. Bacterial isolates from the moribund fish were identified as Yersinia ruckeri by biochemical tests, no lysis by the Hafnia‐specific bacteriophage 1672, and Y. ruckeri‐specific growth patterns on Shotts‐Waltman media. Fingerling catfish injected intraperitoneally with the bacterial isolate at 7.8 × 106 bacteria fish−1 developed lesions characteristic of the epizootics at 13, 18, and 22 °C and a biochemically identical isolate was recovered. Fingerling rainbow trout injected with the channel catfish isolate at 1 × 105 bacteria fish−1 and held at 20 °C developed signs typical of enteric redmouth by 4 days post‐inoculation and were moribund by 5 days post‐inoculation. Some differences of clinical signs occurred between experimentally infected rainbow trout and channel catfish. Clinical and biochemical similarities between infections of Y. ruckeri and many warmwater pathogens in affected catfish may lead to incorrect diagnosis of ERM infections.
Characterization of the adhesion of Flavobacterium columnare (Flexibacter columnaris) to gill tissue
Authors: Decostere A. , Haesebrouck F. , Van Driessche E. , Charlier G. , Ducatelle R. 
Published: March 2003

Abstract Flavobacterium columnare (Flexibacter columnaris) is an important cause of gill and skin disease in freshwater fish species, often causing high mortality. In previous studies, virulence of F. columnare was correlated with the ability to adhere to the gill tissue. To gain insight into the factors responsible for adherence, a gill perfusion model was used. The bacterial cells of the high virulence strain AJS 1 were exposed to various treatments, after which they were added to the organ bath of an isolated gill arch and adherence to the gill tissue assessed. Adherence capabilities were significantly reduced following treatment of the bacteria with sodium metaperiodate or incubating them with d‐glucose, N‐acetyl‐d‐glucosamine, d‐galactose and d‐sucrose. Incubation of the bacteria with trypsin and pronase did not significantly inhibit adherence. The binding sites for F. columnare on the gill tissue were also partially characterised. Treatment of the gill with sodium metaperiodate reduced adhesion, but treatment with pronase or trypsin did not cause any significant reduction, indicating that the major component of the receptor is of carbohydrate nature. Adherence ability of the bacteria correlated well with their haemagglutination capacity using chicken and guinea pig erythrocytes. Higher haemagglutination titres were obtained with the highly virulent strain AJS 1 than with strain AJS 4, a strain with low virulence and adherence capacity. Haemagglutination was partially inhibited after incubation of the bacteria with d‐glucose and N‐acetyl‐d‐glucosamine and after treatment of the bacteria at 41_°C for 10_min (minor heat treatment). It was completely abolished following incubation of the bacterial cells with sodium metaperiodate and intensive heat treatment (65_°C, 25_min). Haemagglutination was also in‐sensitive to pronase and trypsin treatment. Transmission electron microscopy (TEM) revealed that the high virulence strain had a thick capsule (120–130_nm) with a regular, dense appearance, whereas the capsule of the low virulence strain was much thinner (80–90_nm) and less dense. TEM also demonstrated the loss of the capsule of the high virulence strain after treatment of the bacterial cells with minor heat and sodium metaperiodate. These results indicate that a lectin‐like carbohydrate‐binding substance incorporated in the capsule is responsible for the attachment of F. columnare to the gill tissue.
Effects of monensin dose and treatment time on xenoma reduction in microsporidial gill disease in rainbow trout, Oncorhynchus mykiss (Walbaum)
Authors: Becker J A , Speare D J , Daley J , Dick P 
Published: March 2003

AbstractThe objectives of the study were (1) to determine an acceptable dose of dietary monensin against microsporidial gill disease (MGD) of salmon caused by Loma salmonae and (2) to determine the life stage of L. salmonae at which the action of monensin was most effective at reducing clinical disease. Rainbow trout (RBT) were fed monensin diets at concentrations of 0, 10, 100, 1000 and 5000 ppm starting 1 week before per os exposure to L. salmonae infected gill material. Lethal sampling occurred at weeks 6, 7, 8 and 9 post‐exposure (PE). The acceptable dose of dietary monensin was determined to be 1000 ppm because it was the lowest concentration that produced a significant and constant reduction in xenoma formation. RBT were fed monensin at 1000 ppm beginning at 0, 1, 2 and 3 weeks before exposure and at 1, 2 and 3 weeks after exposure and continuing until week 9 PE. Fish in which treatment was initiated at the time of exposure or 1 week before, showed the greatest reduction in xenoma production when compared with the untreated RBT.
Combining diet with physical activity in the treatment of obesity
Authors: Thorogood  
Published: March 2003

As the prevalence of obesity is rising in the population the average energy consumption is falling. It is clear that the missing link is the amount of energy expended. The current recommendations for minimum energy expenditure are 30 min of moderate exercise, such as brisk walking, five times a week, but many people, especially middle‐aged and older women, take little or no exercise. A recent Effective Health Care review on the treatment of obesity concluded that a combination of diet and exercise was more beneficial than diet alone.A systematic review of trials of physical activity promotion concluded that interventions encouraging moderate rather than vigorous intensity exercise, that could be done without recourse to special exercise facilities, were the most likely to succeed. The currently popular ‘Prescription for Exercise’ schemes in the UK have had, at best, limited success. However, evidence is emerging from recent trials of physical activity promotion of new ways to improve initial attendance and long‐term uptake of physical activity.