505 research outputs found
Iris colour in passerine birds: why be bright-eyed?
An initial survey of iris coloration in passerine birds (Aves: Passeriformes) showed that a brightly pigmented iris is much more common in southern African and Australian birds than in those from Europe, temperate North America, and Venezuela. However, the only statistical correlation reflected the distribution of particular bird families in these regions. Ten family-level groups considered to represent monophyletic taxa were then selected for a more detailed analysis, comparing iris coloration with distribution, status, taxonomy, plumage patterns, and some biological and behavioural characters for 1143 species. No pattern associating iris colour with particular traits was common to all families, but within families there were statistically significant associations with both plumage and biology. Our expectation that social behaviour would be an important predictor of iris colour was not supported, but critical information is still lacking for many species. Future studies of avian behavioural ecology should examine critically the role of iris coloration in individual species.Rhodes Centenary issu
Multiplex analysis of osteoarthritic synovial fluid: a comparison of Luminex & Mesoscale discovery
Genetic and morphological variation of the lanternfish lampanyctodes hectoris (myctophiformes: myctophidae) off Southern Africa
Genetic and morphological variation within the southern African population of Lampanyctodes hectoris was
analysed. A total of 15 enzymes, encoding 22 isozyme loci, was examined (n = 327); seven were polymorphic.
The percentage of polymorphic loci ranged from 13.6 to 27.3%. The mean heterozygosity was generally low
and ranged from 0.003 to 0.005. Genetic divergences between specimens from four areas along the west coast
of southern Africa were negligible, genetic distance values (D) ranging from 0 to 0.00011. The results showed
the population of L. hectoris to be genetically invariant. Principal Component Analysis was performed separately
on ratios of 13 morphometric and 6 meristic variables (n = 446), and there was evidence of extensive overlap
between fish from all areas. However, discriminant analysis suggested some morphological variability within
this population. Although genetically the population of L. hectoris seems to be homogenous, morphologically it
appears to be variable. A combination of these results suggests that there is no clear genetic basis for the slight
morphological differentiation within the population
On arbitrages arising from honest times
In the context of a general continuous financial market model, we study
whether the additional information associated with an honest time gives rise to
arbitrage profits. By relying on the theory of progressive enlargement of
filtrations, we explicitly show that no kind of arbitrage profit can ever be
realised strictly before an honest time, while classical arbitrage
opportunities can be realised exactly at an honest time as well as after an
honest time. Moreover, stronger arbitrages of the first kind can only be
obtained by trading as soon as an honest time occurs. We carefully study the
behavior of local martingale deflators and consider no-arbitrage-type
conditions weaker than NFLVR.Comment: 25 pages, revised versio
Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching
Gap junction-mediated intercellular communication influences a variety of cellular activities. In tendons, gap junctions modulate collagen production, are involved in strain-induced cell death, and are involved in the response to mechanical stimulation. The aim of the present study was to investigate gap junction-mediated intercellular communication in healthy human tendon-derived cells using fluorescence recovery after photobleaching (FRAP). The FRAP is a noninvasive technique that allows quantitative measurement of gap junction function in living cells. It is based on diffusion-dependent redistribution of a gap junction-permeable fluorescent dye. Using FRAP, we showed that human tenocytes form functional gap junctions in monolayer and three-dimensional (3-D) collagen I culture. Fluorescently labeled tenocytes following photobleaching rapidly reacquired the fluorescent dye from neighboring cells, while HeLa cells, which do not communicate by gap junctions, remained bleached. Furthermore, both 18âβ-glycyrrhetinic acid and carbenoxolone, standard inhibitors of gap junction activity, impaired fluorescence recovery in tendon cells. In both monolayer and 3-D cultures, intercellular communication in isolated cells was significantly decreased when compared with cells forming many cell-to-cell contacts. In this study, we used FRAP as a tool to quantify and experimentally manipulate the function of gap junctions in human tenocytes in both two-dimensional (2-D) and 3-D cultures
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The surface temperatures of Earth: steps towards integrated understanding of variability and change
Surface temperature is a key aspect of weather and climate, but the term may refer to different quantities that play interconnected roles and are observed by different means. In a community-based activity in June 2012, the EarthTemp Network brought together 55 researchers from five continents to improve the interaction between scientific communities who focus on surface temperature in particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities. The workshop identified key needs for progress towards meeting scientific and societal requirements for surface temperature understanding and information, which are presented in this community paper. A "whole-Earth" perspective is required with more integrated, collaborative approaches to observing and understanding Earth's various surface temperatures. It is necessary to build understanding of the relationships between different surface temperatures, where presently inadequate, and undertake large-scale systematic intercomparisons. Datasets need to be easier to obtain and exploit for a wide constituency of users, with the differences and complementarities communicated in readily understood terms, and realistic and consistent uncertainty information provided. Steps were also recommended to curate and make available data that are presently inaccessible, develop new observing systems and build capacities to accelerate progress in the accuracy and usability of surface temperature datasets
Teaching clinical informatics to third-year medical students: negative results from two controlled trials
BACKGROUND: Prior educational interventions to increase seeking evidence by medical students have been unsuccessful. METHODS: We report two quasirandomized controlled trials to increase seeking of medical evidence by third-year medical students. In the first trial (1997â1998), we placed computers in clinical locations and taught their use in a 6-hour course. Based on negative results, we created SUMSearch(TM), an Internet site that automates searching for medical evidence by simultaneous meta-searching of MEDLINE and other sites. In the second trial (1999â2000), we taught SUMSearch's use in a 5½-hour course. Both courses were taught during the medicine clerkship. For each trial, we surveyed the entire third-year class at 6 months, after half of the students had taken the course (intervention group). The students who had not received the intervention were the control group. We measured self-report of search frequency and satisfaction with search quality and speed. RESULTS: The proportion of all students who reported searching at least weekly for medical evidence significantly increased from 19% (1997â1998) to 42% (1999â2000). The proportion of all students who were satisfied with their search results increased significantly between study years. However, in neither study year did the interventions increase searching or satisfaction with results. Satisfaction with the speed of searching was 27% in 1999â2000. This did not increase between studies years and was not changed by the interventions. CONCLUSION: None of our interventions affected searching habits. Even with automated searching, students report low satisfaction with search speed. We are concerned that students using current strategies for seeking medical evidence will be less likely to seek and appraise original studies when they enter medical practice and have less time
The use of complementary and alternative medicine by women experiencing menopausal symptoms in Bologna
<p>Abstract</p> <p>Background</p> <p>The present study describes Complementary and Alternative Medicine (CAM) use amongst Italian women transitioning through menopause. Popularity and perceived effectiveness of CAM treatments, use of pharmaceutical medications, characteristics of CAM users, the extent of communication between medical practitioners and women about their use of CAM, and variables associated with CAM use were also investigated.</p> <p>Methods</p> <p>Women, aged 45-65 years attending Family Planning and Women's Health clinics or Menopause Centres in Bologna were invited to complete a voluntary, anonymous, self administered questionnaire, which was used in a previous study in Sydney. The questionnaire was translated and adapted for use amongst Italian women. Data on general demographic and health characteristics, menopause related symptoms and the use of CAM and pharmaceutical treatments during the previous 12 months were collected.</p> <p>Results</p> <p>In total, 1,203 women completed the survey, of which 1,106 were included in the final sample. Of women who had symptoms linked with menopause and/or used remedies to alleviate symptoms, 33.5% reported to have used CAM. Among these, 23.5% had consulted one or more practitioners and 24% had used at least one CAM product.</p> <p>Approximately nine out of ten respondents reported medical practitioners did not seek information about their use of CAM; while one third of CAM users did not disclose the use of CAM to their physician. Nevertheless, medical practitioners were the most popular source of information. From the multivariate analysis, variables associated with CAM use were: professional employment, time since the last natural menses, use of CAM for conditions other than menopause, and presence of some severe symptoms.</p> <p>Conclusions</p> <p>The relatively high prevalence of CAM use by women transitioning through menopause should encourage research initiatives into determining which CAM treatments are the safest and effective. The increasing and likely concomitant use of CAM with HRT and other pharmaceuticals underlines the need for the implementation of a surveillance system to report and monitor possible drug-herb adverse events. The discrepancy between women preferring to seek information about CAM from their medical doctor and the difficulties noted in communication between doctor and patient should encourage educational initiatives on CAM by health-care agencies and institutions.</p
The biology of plateletrich plasma and its application in trauma and orthopaedic surgery
Although mechanical stabilisation has been a hallmark of orthopaedic surgical management, orthobiologics are now playing an increasing role. Platelet-rich plasma (PRP) is a volume of plasma fraction of autologous blood having platelet concentrations above baseline. The platelet ι granules are rich in growth factors that play an essential role in tissue healing, such as transforming growth factor-β, vascular endothelial growth factor, and platelet-derived growth factor. PRP is used in various surgical fields to enhance bone and soft-tissue healing by placing supraphysiological concentrations of autologous platelets at the site of tissue damage. The easily obtainable PRP and its possible beneficial outcome hold promise for new regenerative treatment approaches. The aim of this literature review was to describe the bioactivities of PRP, to elucidate the different techniques for PRP preparation, to review animal and human studies, to evaluate the evidence regarding the use of PRP in trauma and orthopaedic surgery, to clarify risks, and to provide guidance for future research
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