Finding qualitative research: an evaluation of search strategies

BACKGROUND: Qualitative research makes an important contribution to our understanding of health and healthcare. However, qualitative evidence can be difficult to search for and identify, and the effectiveness of different types of search strategies is unknown. METHODS: Three search strategies for qualitative research in the example area of support for breast-feeding were evaluated using six electronic bibliographic databases. The strategies were based on using thesaurus terms, free-text terms and broad-based terms. These strategies were combined with recognised search terms for support for breast-feeding previously used in a Cochrane review. For each strategy, we evaluated the recall (potentially relevant records found) and precision (actually relevant records found). RESULTS: A total yield of 7420 potentially relevant records was retrieved by the three strategies combined. Of these, 262 were judged relevant. Using one strategy alone would miss relevant records. The broad-based strategy had the highest recall and the thesaurus strategy the highest precision. Precision was generally poor: 96% of records initially identified as potentially relevant were deemed irrelevant. Searching for qualitative research involves trade-offs between recall and precision. CONCLUSIONS: These findings confirm that strategies that attempt to maximise the number of potentially relevant records found are likely to result in a large number of false positives. The findings also suggest that a range of search terms is required to optimise searching for qualitative evidence. This underlines the problems of current methods for indexing qualitative research in bibliographic databases and indicates where improvements need to be made

Omega Meson Cloud and the Proton's Light Anti-Quark Distribution

We use the meson cloud model of the nucleon to calculate distribution functions for $(\bar {d} - \bar{u})$ and $\bar{d}/\bar{u}$ in the proton. Including the effect of the omega meson cloud, with a coupling constant $g_\omega^2/4\pi\approx 8$, allows a reasonably good description of the data.Comment: 6 pages, 2 figures, LaTe

Phytoplankton Dynamics of Two North Carolina Coastal Plain Swamps: Species Composition, Seasonal Periodicity and Impact of Wastewater Discharge

INTRODUCTION: Wetland Values: Wetlands are valuable ecosystems which serve to interface land and water systems. Saturation of the soil and type of vegetation are major criteria which define wetlands (Cowardin, et al. 1979). These ecosystems support diverse plant and animal communities and the magnitude of primary productivity in wetlands is of global importance. In addition, wetlands provide sanctuary to many threatened and endangered species of plants and animals. Wetland ecosystems also have many valuable hydrologic functions. In palustrine forested wetlands, commonly called swamps, the inundation of the soil varies with the season and the amount of precipitation and runoff. One of the predominant values of wetlands is their capacity to serve as sites of water retention and flood control. They are also traps for suspended sediments and nutrients, thus improving the water quality downstream (Carter, et al.,1979). Because of their potential to improve water quality, wetlands have also been used as tertiary treatment for municipal wastewater discharge (Brinson and Westall, 1983; Richardson and Nichols, 1986), However, such uses are inappropriate if using the wetland as a site for sewage treatment will alter the valuable ecologic and hydrologic functions of the wetland.Master of Science in Public Healt

Light quark distributions in the proton sea

We use the meson cloud model to calculate $\bar{d}(x) - \bar{u}(x)$ and $\bar{d}(x)/\bar{u}(x)$ in the proton. We show that a modification of the symmetric, perturbative part of the light quark sea provides better agreement with the ratio $ \bar{d}(x)/\bar{u}(x).Comment: 4 pages, 2 figures, LaTeX. Talk presented at PANIC 9

Parton distributions in the proton and pion

We use detailed balance for a hadron composed of quark and gluon Fock states to obtain parton distributions in the proton and pion on the basis of a simple statistical model.Comment: 13 pages, 5 figure

Neurosyphilis: An Important Cause of Recurrent Strokes

Background: Neurosyphilis can manifest as recurrent brain infarction, although not frequently, but can be challenging to diagnose due to atypical presentations. Case report: A 43-year-old male with history of smoking presented to the Midland Regional Hospital, Tullamore (MRHT), Offaly, Ireland, with focal speech deficit and arm/leg weakness for 3 days. Neuroimaging showed acute cerebral infarction. He denied any high-risk sexual contacts. Forty-eight hour telemetry, trans-thoracic echocardiogram, cerebral catheter angiogram, and magnetic resonance angiogram were normal. He was treated with high-dose aspirin for 14 days and then discharged on aspirin with a follow-up plan. Trans-oesophageal echocardiogram performed after 2 weeks showed no evidence of subacute bacterial endocarditis, but there was evidence of fibroelastoma on the aortic valve. The cardiology department felt this was not a likely cardioembolic source. The patient presented 2 months later with recurrent stroke symptoms of loss of speech to another hospital. However, he was discharged for follow-up in MRHT as symptoms resolved. Brain computed tomography (CT) showed ‘old’ stroke. One week later he re-presented to MRHT with dysarthria, ataxia, and a National Institute of Health Stroke Scale (NIHSS) score of three. Repeated neuroimaging showed multiple ‘new’ and ‘old’ cerebral infarcts. The patient was anticoagulated based on recurrent thromboembolic events and magnetic resonance imaging was repeated. CT aortogram and 48-hour Holter results were normal. A repeated magnetic resonance angiogram showed multiple stenosis areas due to vasculitis. As aetiology was complex, a lumbar puncture was performed and blood tests repeated (viral serology, vasculitic and thrombophilia screens). Cerebrospinal fluid and serum analysis displayed a diagnosis of neurosyphilis with co-infection of HIV. Treatment with penicillin was commenced, after which the patient greatly improved and is now under long-term follow-up. Conclusion: Stroke in a young patient is rare and recurrent stroke-like events in a young person raise the clinical suspicion of an alternative diagnosis. It is therefore imperative to investigate neurosyphilis in all HIV-positive patients, as it can cause early clinical manifestation in such patients

Exploring the Expression of Cardiac Regulators in a Vertebrate Extremophile: The Cichlid Fish Oreochromis (Alcolapia) alcalica

Although it is widely accepted that the cellular and molecular mechanisms of vertebratecardiac development are evolutionarily conserved, this is on the basis of data from only a fewmodel organisms suited to laboratory studies. Here, we investigate gene expression during cardiacdevelopment in the extremophile, non-model fish species, Oreochromis (Alcolapia) alcalica. Wefirst characterise the early development of O. alcalica and observe extensive vascularisation across the yolk prior to hatching. We further investigate heart development by identifying andcloning O. alcalica orthologues of conserved cardiac transcription factors gata4, tbx5, and mef2cfor analysis by in situ hybridisation. Expression of these three key cardiac developmentalregulators also reveals other aspects of O. alcalica development, as these genes are expressed indeveloping blood, limb, eyes, and muscle, as well as the heart. Our data support the notion that O.alcalica is a direct-developing vertebrate that shares the highly conserved molecular regulation ofthe vertebrate body plan. However, the expression of gata4 in O. alcalica reveals interestingdifferences in the development of the circulatory system distinct from that of the well-studiedzebrafish. Understanding the development of O. alcalica embryos is an important step towardsproviding a model for future research into the adaptation to extreme conditions; this is particularlyrelevant given that anthropogenic-driven climate change will likely result in more freshwaterorganisms being exposed to less favourable conditions