36 research outputs found

    Effects of Population Size and Density On Pollinator Visitation, Pollinator Behavior, and Pollen Tube Abundance in Lupinus Perennis

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    Both the number and the density of flowering plants in a population can be important determinants of pollinator abundance and behavior. We report the joint effects of population size and density on pollinator visitation and pollination success for Lupinus perennis (Fabaceae). Focusing on five pairs of populations, we matched one small population (125-800 flowering plants) with one distinctly larger population (1000-3000 flowering plants). In these pairs, population size did not affect pollinator communities or pollination success. All measures of pollination success increased significantly with density. Only bee behavior (number of flowers probed per inflorescence) exhibited a significant interaction of size and density. Testing whether population sizes smaller than those in the paired populations might affect pollination, we gathered pollen tube samples from 14 unpaired populations (16-215 flowering plants). Combining these data with those from the paired populations revealed a significant decrease in pollination for smaller populations, indicating that effects of population size may be detectable only when populations smaller than a few hundred plants are sampled. We found that effects of density are consistent and much stronger than those of population size. Our results suggest that both size and density of natural populations should be considered in designing restoration and reintroduction programs for this threatened plant

    Supervised exercise training as an adjunctive therapy for venous leg ulcers: study protocol for a randomised controlled trial

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    Background: Venous leg ulcers are common, chronic wounds that are painful and reduce quality of life. Compression therapy is known to assist in the healing of venous leg ulceration. Supervised exercise training that targets an improvement in calf muscle pump function might be a useful adjunctive therapy for enhancing ulcer healing and other aspects of physical and mental health. However, the evidence of exercise for individuals with venous ulcers is sparse. Here, we describe the protocol for a study that aims to assess the feasibility of undertaking a randomised controlled trial of a supervised exercise programme in people who are receiving compression for venous ulceration. Methods/Design: This is a randomised, controlled, assessor-blinded, two-centre, feasibility trial with two parallel groups. Eighty adults who are receiving lower-limb compression for a venous leg ulcer will be randomly assigned to receive usual care (compression only) or usual care plus a 12-week supervised exercise programme. Participants in the exercise group will be invited to undertake three, 60-minute sessions of supervised exercise each week, and each session will involve a combination of treadmill walking, upright cycling and strength and flexibility exercises for the lower limbs. Participants will be assessed before randomisation and 3, 6 and 12 months after randomisation. Primary outcomes include rates of recruitment, retention and adherence. Secondary outcomes include time to ulcer healing, proportion of participants healed, percentage and absolute change in ulcer size, health-related quality of life (EQ-5D-5L and VEINES-QOL/Sym), lower-limb cutaneous microvascular function (laser Doppler flowmetry coupled with iontophoresis) and physical fitness (30-second sit-to-stand test, chair sit and reach test, 6-minute walk test and ankle range of motion). The costs associated with the exercise programme and health-care utilisation will be calculated. We will also complete interviews with a sub-sample of participants to explore their experiences of having a venous ulcer and the acceptability of the exercise intervention and study procedures. Discussion: Data from this study will be used to refine the supervised exercise programme, investigate the acceptability of the intervention and study design and determine the most appropriate outcome measures, thereby providing estimates of the factors needed to design an adequately powered trial across several centres

    Impact of Carotid Artery Stenosis on Quality of Life: A Systematic Review

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    © 2018, Springer Nature Switzerland AG. Objectives: The aim of this study was to identify themes that determine health-related quality of life (HRQoL) in patients with carotid artery stenosis and identify the patient-reported outcome measures (PROMs) that best cover the identified themes. Methods: A systematic review of the main six databases from inception to September 2018 was undertaken to identify primary qualitative studies reporting on the HRQoL of patients with carotid artery stenosis. The quality of studies was assessed using the Critical Appraisal Skills Programme (CASP) criteria. Findings from the included studies were analysed using framework analysis methodology. The identified themes were mapped against the items/domains from the PROMs used previously in patients with carotid artery stenosis. Results: The systematic review identified four papers that fulfilled the inclusion criteria. The included papers reported the views of 62 patients with symptomatic carotid artery stenosis; 24 of the patients were awaiting assessment for intervention, 26 had carotid endarterectomy, and 12 were turned down for intervention and received best medical therapy. The overall quality of the included studies was good based on CASP criteria. Framework analysis identified 16 themes that were divided into five main domains: anxiety, impact on personal roles and activities, effect on independence, psychological impact, and symptoms. The best-fit generic and disease-specific PROMs were the Medical Outcomes Study 36-Item Short Form (SF-36®) and the Carotid Stenosis Specific Outcome Measure (CSSOM), respectively. None of the PROMs covered all the themes identified in the qualitative systematic review. Conclusion: The findings from the review identified the important themes that affect patients with carotid stenosis disease. The current generic and disease-specific PROMs do not cover all themes that impact the HRQoL of patients suffering with this disease. The proposed themes can be used to develop a new disease-specific PROM to measure HRQoL

    Prevalence of Abnormalities in Vestibular Function and Balance among HIV-Seropositive and HIV-Seronegative Women and Men

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    BACKGROUND: Most HIV-seropositive subjects in western countries receive highly active antiretroviral therapy (HAART). Although many aspects of their health have been studied, little is known about their vestibular and balance function. The goals of this study were to determine the prevalences of vestibular and balance impairments among HIV-seropositive and comparable seronegative men and women and to determine if those groups differed. METHODS: Standard screening tests of vestibular and balance function, including head thrusts, Dix-Hallpike maneuvers, and Romberg balance tests on compliant foam were performed during semiannual study visits of participants who were enrolled in the Baltimore and Washington, D. C. sites of the Multicenter AIDS Cohort Study and the Women's Interagency HIV Study. RESULTS: No significant differences by HIV status were found on most tests, but HIV-seropositive subjects who were using HAART had a lower frequency of abnormal Dix-Hallpike nystagmus than HIV-seronegative subjects. A significant number of nonclassical Dix-Hallpike responses were found. Age was associated with Romberg scores on foam with eyes closed. Sex was not associated with any of the test scores. CONCLUSION: These findings suggest that HAART-treated HIV infection has no harmful association with vestibular function in community-dwelling, ambulatory men and women. The association with age was expected, but the lack of association with sex was unexpected. The presence of nonclassical Dix-Hallpike responses might be consistent with central nervous system lesions

    Themes that Determine Quality of Life in Patients with Peripheral Arterial Disease: A Systematic Review

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    © 2018 Springer International Publishing AG, part of Springer Nature Objectives: The aim of this study was to identify domains that determine quality of life in patients with peripheral arterial disease and find the patient-reported outcome measures that can examine the identified themes. Methods: A systematic review of all the main six databases was undertaken to identify primary qualitative studies reporting on the health and/or quality of life of patients with peripheral arterial disease. The quality of studies was assessed using the Critical Appraisal Skills Program criteria. Findings from the included studies were analysed using framework analysis methodology. The identified themes were mapped against the items/domains of validated patient-reported outcome measures used in patients with peripheral arterial disease. Results: The systematic review identified eight papers that fulfilled the inclusion criteria. The included papers reported the views of 186 patients with peripheral arterial disease including patients with intermittent claudication, critical ischaemia and amputation secondary to peripheral arterial disease. The overall quality of the included studies was good based on Critical Appraisal Skills Program criteria. Framework analysis identified 35 themes that were divided into six main groups: symptoms, impact on physical functioning, impact on social functioning, psychological impact, financial impact and process of care. The best-fit generic and disease-specific patient-reported outcome measures were the Nottingham Health Profile and the Vascular Quality of Life Questionnaire, respectively. None of the patient-reported outcome measures covered all the themes important to patients with peripheral arterial disease. Discussion: The findings from the review identified the important domains that affect patients living with peripheral arterial disease. None of the current generic and disease-specific patient-reported outcome measures provide a comprehensive measure for all themes that impact the daily living of patients with peripheral arterial disease

    Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL

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    We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants, respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO or RuBPCase). We used two different state-transformation assumptions resulting in two sets of cladograms: (i) equal-weighting for the 499-taxon analysis; and (ii) a procedure that differentially weights transversions over transitions within characters and codon positions among characters for the 475-taxon analysis. The degree of congruence between these results and other molecular, as well as morphological, cladistic studies indicates that rbcL sequence variation contains historical evidence appropriate for phylogenetic analysis at this taxonomic level of sampling. Because the topologies presented are necessarily approximate and cannot be evaluated adequately for internal support, these results should be assessed from the perspective of their predictive value and used to direct future studies, both molecular and morphological. In both analyses, the three genera of Gnetales are placed together as the sister group of the flowering plants, and the anomalous aquatic Ceratophyllum (Ceratophyllaceae) is sister to all other flowering plants. Several major lineages identified correspond well with at least some recent taxonomic schemes for angiosperms, particularly those of Dahlgren and Thorne. The basalmost clades within the angiosperms are orders of the apparently polyphyletic subclass Magnoliidae sensu Cronquist. The most conspicuous feature of the topology is that the major division is not monocot versus dicot, but rather one correlated with general pollen type: uniaperturate versus triaperturate. The Dilleniidae and Hamamelidae are the only subclasses that are grossly polyphyletic; an examination of the latter is presented as an example of the use of these broad analyses to focus more restricted studies. A broadly circumscribed Rosidae is paraphyletic to Asteridae and Dilleniidae. Subclass Caryophyllidae is monophyletic and derived from within Rosidae in the 475-taxon analysis but is sister to a group composed of broadly delineated Asteridae and Rosidae in the 499-taxon study

    Seed size variation: magnitude, distribution, and ecological correlates

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    We examined seed-mass variation in 39 species (46 populations) of plants in eastern-central Illinois, USA. The coefficient of variation of seed mass commonly exceeded 20%. Significant variation in mean seed mass occurred among conspecific plants in most species sampled (by hierarchical ANOVA), averaging 38% of total variance. For most species, within-plant variation was the larger component of total variance, averaging 62% of total variance. Variation in seed mass among fruits within crops was significant in most species tested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42741/1/10682_2005_Article_BF02067274.pd

    Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL

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    We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants, respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO or RuBPCase). We used two different state-transformation assumptions resulting in two sets of cladograms: (i) equal-weighting for the 499-taxon analysis; and (ii) a procedure that differentially weights transversions over transitions within characters and codon positions among characters for the 475-taxon analysis. The degree of congruence between these results and other molecular, as well as morphological, cladistic studies indicates that rbcL sequence variation contains historical evidence appropriate for phylogenetic analysis at this taxonomic level of sampling. Because the topologies presented are necessarily approximate and cannot be evaluated adequately for internal support, these results should be assessed from the perspective of their predictive value and used to direct future studies, both molecular and morphological. In both analyses, the three genera of Gnetales are placed together as the sister group of the flowering plants, and the anomalous aquatic Ceratophyllum (Ceratophyllaceae) is sister to all other flowering plants. Several major lineages identified correspond well with at least some recent taxonomic schemes for angiosperms, particularly those of Dahlgren and Thorne. The basalmost clades within the angiosperms are orders of the apparently polyphyletic subclass Magnoliidae sensu Cronquist. The most conspicuous feature of the topology is that the major division is not monocot versus dicot, but rather one correlated with general pollen type: uniaperturate versus triaperturate. The Dilleniidae and Hamamelidae are the only subclasses that are grossly polyphyletic; an examination of the latter is presented as an example of the use of these broad analyses to focus more restricted studies. A broadly circumscribed Rosidae is paraphyletic to Asteridae and Dilleniidae. Subclass Caryophyllidae is monophyletic and derived from within Rosidae in the 475-taxon analysis but is sister to a group composed of broadly delineated Asteridae and Rosidae in the 499-taxon study
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