bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metastasis‐free survival following treatment for uveal melanoma with either stereotactic radiosurgery or enucleation
Authors: Cohen V. M. L. , Carter M. J. , Kemeny A. , Radatz M. , Rennie I. G. 
Published: July 2003

Abstract.Purpose:  To determine whether metastasis‐free survival following stereotactic radiosurgery is comparable with that following enucleation in a cohort of patients with choroidal and ciliary body melanoma.Methods:  This was a non‐randomized, retrospective study of 196 patients with uveal melanoma treated between 1990 and 2000. A total of 118 eyes were enucleated and 78 eyes were treated with stereotactic radiosurgery. The following variables were recorded: age and sex of patient; tumour location, volume and height; the presence of retinal detachment, and extrascleral extension. Tumour location was divided into three categories: within the posterior pole; beyond the limits of the posterior pole but not including the ciliary body, and ciliary body location. Analysis of survival time was performed using Kaplan−Meier estimation of survival curves and Cox's proportional hazards regression modelling.Results:  The 5‐year cumulative metastasis‐free survival rate was 51% in the enucleation treatment group compared to 74% in the stereotactic treatment group. However, in the multivariate analysis there was no statistical difference in survival rates between the two treatment groups. The only variables that influenced survival rates were tumour location (p = 0.002), ciliary body tumours with the worst prognosis, and tumour volume (p = 0.001).Conclusions:  Tumour size and location at presentation determined metastasis‐free survival. Large ciliary body tumours had the highest risk of metastasis. Metastasis‐free survival after stereotactic radiosurgery was comparable to that after enucleation.
Aqueous humour flow after a single oral dose of isosorbide‐5‐mononitrate in healthy volunteers
Authors: Kotikoski Hanna , Oksala Olli , Vapaatalo Heikki , Aine Esko 
Published: July 2003

Abstract.Purpose:  To investigate whether a nitric oxide donor given as a single oral dose is able to modify aqueous humour flow in healthy volunteers.Methods:  Ten healthy volunteers participated in a randomized, double‐masked and placebo‐controlled cross‐over study. Aqueous humour flow was assessed by fluorophotometry after intake of isosorbide‐5‐mononitrate (ISMN), 10 mg. Topical timolol maleate, which is known to reduce aqueous humour flow, was used as a positive control. Intraocular pressure (IOP) was measured by applanation tonometry and blood pressure was registered.Results:  The basal rate of aqueous humour flow did not change significantly after a single oral dose of ISMN. The aqueous humour flow in the timolol‐treated eye was reduced as compared to the contralateral control eye (p = 0.002). Mean IOP 6 hours after placebo and ISMN intake did not differ significantly. Timolol lowered IOP by 4 mmHg (p < 0.001). ISMN did not lower systolic blood pressure, but diastolic blood pressure was reduced by 4 mmHg (p = 0.048).Conclusion:  A single oral dose of 10 mg ISMN had no significant effect on aqueous humour flow in healthy volunteers.
Physicians' liability in ophthalmology practice
Authors: Mavroforou Anna , Michalodimitrakis Emmanuel 
Published: July 2003

Abstract.Purpose:  The aims of this paper are to point out the importance of coherence in established guidelines in daily practice, highlight the value of signed patient informed consent forms and stress the value of a good understanding of the law, while focusing on issues related to malpractice in ophthalmology.Methods:  Search of the current relevant literature.Results:  The most common causes of medical litigation in ophthalmology are related to LASIK surgery, cataract surgery, glaucoma care, radial keratotomy for myopia reduction and failure to diagnose binocular vision anomalies in children and adults in a timely fashion. The litigation raised in most cases is driven by unfavourable outcomes and not by malpractice.Conclusion:  Maintenance of high standards in daily practice, with continuous training and clear communication along with the appropriate documentation of any procedure carried out, may improve the professional safety of practising eye specialists in the event of medical litigation. Although the use of patient informed consent varies substantially among European countries, it may serve as useful evidence in the physician's defence.
Growth and reproduction of three cladoceran species from a small wetland in the south‐eastern U.S.A.
Authors: Lemke A. M. , Benke A. C. 
Published: July 2003

SUMMARY 1. Growth, reproduction and life‐history parameters were measured for three cladoceran species from a small south‐eastern wetland, U.S.A. Simocephalus serrulatus, Diaphanosoma brachyurum and Scapholeberis mucronata juveniles were reared at temperatures between 10 and 25 °C on natural food resources.2. Growth rate increased with temperature and decreased with individual size for all three species. Maximum somatic growth rate was higher for Simocephalus (49–72% day−1) and Diaphanosoma (21–91% day−1) than for Scapholeberis (11–45% day−1). Multiple regression equations were developed which predict temperature‐ and mass‐specific growth rates for each species.3. Scapholeberis egg production was positively related to temperature; however, maximum egg production occurred at intermediate temperatures for Simocephalus and Diaphanosoma. Mean cumulative egg production was higher for Scapholeberis (28–92 eggs per female) than for Simocephalus (18–25 eggs per female) and Diaphanosoma (1–41 eggs per female), and was related to differences in reproductive strategy and survival.4. Survival was inversely related to temperature in most cases. For all three cladocerans, the intrinsic rate of increase (r) and net reproductive rate (R0) increased with temperature, whereas generation time (G) decreased. Greater egg production by Scapholeberis compared with the other two cladocerans was consistent with higher R0 values for Scapholeberis at any given temperature. Although r was very similar among species, G was typically longer for Scapholeberis than for Simocephalus and Diaphanosoma.5. This analysis provides basic information about the population parameters of these coexisting wetland species, and the growth rate models can be applied to field data to determine production dynamics.
Spatio‐temporal heterogeneity in a planktonic Thiocystis minor population, studied by laser in situ particle analysis
Authors: Serra Teresa , Colomer Jordi , Soler Marianna , Vila Xavier 
Published: July 2003

SUMMARY1. The development of a population of Thiocystis minor (formerly Chromatium minus) in the deepest, anoxic layers of Moncortès Lake (Lleida, Spain) was studied by means of an in situ, laser particle analyser. Particle size distribution was measured at hourly and monthly time intervals.2. The population was located between the redoxcline (∼3 m below the mean population depth) and the oxycline (∼6 m above the mean population depth) with a seasonal vertical displacement (SVD) of up to 6 m (from April to October).3. Diel vertical migration of the population was followed in three field campaigns, when the population was most abundant. The largest vertical displacement was 2.8 m (in 11.5 h) and the fastest vertical displacement was 0.6 m h−1. Sudden changes in the irradiance reaching the bacterial population were detected by the cells, which moved up or down, rapidly modifying the mean vertical position of the population.4. There was positive phototaxis with an ascent during the morning and a descent during the afternoon/night. The whole population was active while migrating upwards (towards higher light intensity) or downwards (towards lower redox concentration).
Influences of habitat complexity on the diversity and abundance of epiphytic invertebrates on plants
Authors: Taniguchi Hiromi , Nakano Shigeru , Tokeshi Mutsunori 
Published: July 2003

SUMMARY 1. The compound influence of habitat complexity and patch size on stream invertebrate assemblages associated with submerged macrophytes was investigated through field sampling of two natural macrophyte species with contrasting leaf morphologies (complex, Ranunculus yezoensis; simple, Sparganium emersum) and an experiment with two artificial plants with different levels of morphological complexity.2. The artificial plant experiment was designed to separate the effects of habitat area (patch size) and habitat complexity, thus enabling a more rigorous assessment of complexity per se than in previous studies where only a single patch size was used. Simple and complex artificial plants were established with five different patch sizes corresponding to the range found in natural plants.3. Invertebrates occurred on both complex and simple forms of natural and artificial plants at similar abundances with dipterans and ephemeropterans being predominant. Taxon richness was higher on structurally complex Ranunculus than on simple Sparganium and was similarly higher on the complex artificial plant than on the simple one, over the entire range of habitat patch sizes. Thus, architectural complexity affected the taxon richness of epiphytic invertebrates, independently of habitat scale.4. On the natural plants there was no difference in the abundance (both number of individuals and biomass) of invertebrates between simple and complex forms, while on artificial plants more invertebrates occurred on complex than on simple forms. The amount of particulate organic matter, >225 μm (POM) and chlorophyll a showed mixed patterns on natural and artificial plants, suggesting that the availability of these resources is not an overriding proximate factor controlling invertebrate abundance on plants. The difficulty of extrapolating from experimental results involving use of artificial plants is discussed, especially when considering the relationship between habitat structure and the occurrence of epiphytic invertebrates on natural plants.
Changes in population biology of two succulent shrubs along a grazing gradient
Authors: Riginos Corinna , Hoffman M. Timm 
Published: July 2003

Summary

Heavy livestock grazing in Namaqualand, South Africa, is threatening the region's unique diversity of succulent shrubs. This is especially true in the communally managed lands, where grazing is centred around fixed enclosures (stockposts) in which animals stay overnight. In this study we set out to determine the effects of a semi‐permanent stockpost on the composition of the surrounding vegetation and the mechanisms by which grazing limits the persistence of leaf‐succulent shrub populations.
We used the grazing gradient created by a stockpost to examine the impacts of grazing on vegetation composition and changes in mortality, reproductive output and seedling establishment for the leaf‐succulent species Ruschia robusta and Cheiridopsis denticulata.
Vegetation composition was found to change from a community dominated by the unpalatable shrub Galenia africana at high grazing intensities to a community dominated by the palatable leaf‐succulent shrub R. robusta at lower grazing intensities.
Mortality of the leaf‐succulents R. robusta and C. denticulata was high at the sites closest to the stockpost, while fruit production and seedling germination were substantially reduced over distances of 800 m and 2 km for the two species, respectively. Seedling establishment was not limited by either grazing or microsite availability. Thus reduction in reproductive output is the greatest impact of heavy grazing on these two species.
Synthesis and applications. This study demonstrates that marked zonation in vegetation composition and population biology can develop around a fixed stockpost and that the greatest impact of grazing on the two leaf‐succulent species studied is the suppression of flower and fruit production. Consistent suppression of reproductive output could have long‐term consequences for the persistence of succulent shrub populations in the heavily grazed communal lands of Namaqualand. We recommend that (i) herders should be encouraged to relocate their stockposts regularly to prevent the development of centres of degradation, and (ii) areas should be relieved periodically of all grazing pressure to allow for successful seed set of native shrubs.
Vertical structure and basal area development in second‐growthNothofagusstands in Chile
Authors: Lusk Christopher H. , Ortega Alicia 
Published: July 2003

SummarySome studies have shown that mixed forest stands can develop more biomass or basal area than pure stands when the component species occupy different strata. It has been predicted that such additive effects are most likely in moist habitat sites where size‐asymmetric competition controls stand development.In south‐central Chile, secondary succession often gives rise to vertically stratified mixed forest stands, with aNothofagusoverstorey overtopping lower tiers dominated by more shade‐tolerant taxa. We examined the relationship between the degree of understorey development and total basal area accumulated by 83 second‐growthNothofagusstands aged 40–70 years. Basal area is defined as the cross‐sectional area at breast height of all trees in a stand, per unit land area.When age, overstorey leaf habit and geographical location were controlled byancova, stands with a heavy understorey (> 6 m2 ha−1) yielded > 25% more total basal area on average than stands with little or no understorey. The average basal area of theNothofaguscomponent did not differ significantly between stand structure categories.The total basal area of stands dominated by evergreenN. dombeyiwas nearly 50% higher on average than that of stands of similar age dominated by deciduousN. obliquaand/orN. nervosa, reflecting denser stockings in the former as a result of allometric differences. Although the percentage of total stand basal area contributed by the understorey was higher on deciduous‐dominant plots, mean absolute basal area of understorey associates was similar beneath evergreen and deciduousNothofagusoverstoreys.Synthesis and applications. The results broaden the evidence for additive effects in mixtures of species with complementary light use, suggesting that no significant advantage to overstorey wood production will be gained by eliminating a woody understorey inNothofagussecond‐growth stands on mesic sites. Despite the minor contribution of the understorey to merchantable timber volume, other benefits and ecosystem services associated with subcanopy species in these stands can be regarded as additive to benefits obtained from theNothofagusoverstorey. Our findings are also consistent with the proposal that size‐asymmetric competition controls stand development after canopy closure on mesic sites.
Predicting spatial aspects of human–elephant conflict
Authors: Sitati N. W. , Walpole M. J. , Smith R. J. , Leader‐Williams N. 
Published: July 2003

SummaryHuman–elephant conflict (HEC) in Africa occurs wherever these two species coincide, and poses serious challenges to wildlife managers, local communities and elephants alike. Mitigation requires a detailed understanding of underlying patterns and processes. Although temporal patterns of HEC are relatively predictable, spatial variation has shown few universal trends, making it difficult to predict where conflict will take place. While this may be due to unpredictability in male elephant foraging behaviour (the male behaviour hypothesis) it may also be due to variations in the data resolution of earlier studies.This study tested the male behaviour and data resolution hypotheses using HEC data from a 1000‐km2unprotected elephant range adjacent to the Masai Mara National Reserve in Kenya. HEC incidents were divided into crop raiding and human deaths or injuries. Crop raiding was further subdivided into incidents involving only male elephants or family groups. A relatively fine‐resolution, systematic, grid‐based method was used to assign the locations of conflict incidents, and spatial relations with underlying variables were explored using correlation analysis and logistic regression.Crop raiding was clustered into distinct conflict zones. Both occurrence and intensity could be predicted on the basis of the area under cultivation and, for male elephant groups, proximity to major settlements. Conversely, incidents of elephant‐induced human injury and death were less predictable but were correlated with proximity to roads.A grid‐based geographical information system (GIS) with a 25‐km2resolution utilizing cost‐effective data sources, combined with simple statistical tools, was capable of identifying spatial predictors of HEC. At finer resolutions spatial autocorrelation compromised the analyses.Synthesis and applications. These results suggest that spatial correlates of HEC can be identified, regardless of the sex of the elephants involved. Moreover, the method described here is fully transferable to other sites for comparative analysis of HEC. Using these results to map vulnerability will enable the development and deployment of appropriate conflict mitigation strategies, such as guarding, early warning systems, barriers and deterrents. The utility of such methods and their strategic deployment should be assessed alongside alternative land‐use and livelihood strategies that limit cultivation within the elephant range.
Dispersal characteristics and management of a rare damselfly
Authors: Purse Bethan V. , Hopkins Graham W. , Day Kieron J. , Thompson David J. 
Published: July 2003

SummaryCoenagrion mercurialeis a rare damselfly in Britain and mainland Europe and has been declining in the last 30 years. It has specialized habitat requirements and has been viewed, traditionally, as a poor disperser. Knowledge of its dispersal ability was considered in its Biodiversity Species Action Plan as essential for the formulation of appropriate conservation management strategies.Mark–release–recapture (MRR) studies ofC.mercurialein two large UK heathland populations were undertaken. Mature adults had a low rate of movement within continuous areas of habitat (average < 25 m movement), low emigration rates (1·3–11·4%) and low colonization distances (maximum 1 km), all comparable to similarly sized coenagrionids.Movements were more likely within than between patches of suitable habitat over short to medium distances (50–300 m). Between‐patch movements were more likely between patches that were close together. Scrub barriers reduced dispersal.The probability of dispersal between two recaptures depended on the length of the time interval between them.Coenagrion mercurialeperformed considerable between‐patch movements within a small fraction (1–2 days) of its mean mature adult life span (7–8 days).Qualitative comparison of field colonization distances measured here and distances between UK sites occupied byC.mercurialerevealed that empty sites within large clusters of sites would probably be recolonized rapidly and dispersal events would be frequent. However, such events would occur rarely within small isolated sites or clusters of sites, leaving local populations prone to extinction.Synthesis and applications.These data show that management effort should be directed towards maximizing the likelihood ofC.mercurialerecolonizing sites naturally within 1–3 km of other populations (particularly within large clusters). Scrub boundaries should be removed between existing populations and empty, but suitable, sites to facilitate stepping‐stone dispersal movements.
An ecosystem‐based approach to management: using individual behaviour to predict the indirect effects of Antarctic krill fisheries on penguin foraging
Authors: Alonzo Suzanne H. , Switzer Paul V. , Mangel Marc 
Published: July 2003

SummaryChanges in species’ abundance and distributions caused by human disturbances can have indirect effects on other species in a community. Although ecosystem approaches to management are becoming increasingly prevalent, they require a fuller understanding of how individual behaviour determines interactions within and between species.Ecological interactions involving krill are of major importance to many species within the Antarctic. Despite extensive knowledge of the ecosystem that they occupy, there is still incomplete understanding of the links between species and the effect of environmental conditions on these interactions. In this study, we extended a behavioural model used previously to understand the interactions between penguins and krill to determine the indirect effect of krill fisheries on penguin foraging success and behaviour in adjacent breeding sites.Increased fishing pressure offshore is predicted to reduce penguin food intake. Given the documented links between krill and penguins, this also leads to a prediction of decreased penguin survival and reproduction. Krill behaviour is predicted to cause stronger effects of krill fisheries than explained solely by the percentage of biomass removed. Environmental conditions that decrease krill growth rates or cause krill to spend time in deeper water are also predicted to increase the magnitude of the effect of fishing on penguin success. We show that changes in penguin foraging behaviour can be used to assess the impact of local fisheries on penguin reproductive success.Synthesis and applications. These results demonstrate that an understanding of predator–prey interactions, indirect effects between species, and individual behaviour is imperative to our ability to manage populations. We describe a general method to use what is known about ecological and evolutionary processes with species‐specific information to predict the response of organisms to novel situations. We further show how individual behaviour can be used to assess the impact of human disturbance on ecosystems.