2,154 research outputs found
Effect of supplementary feeding on reproductive success of hihi (stitchbird, Notiomystis cincta) at a mature forest reintroduction site
Supplementary feeding has proven to be a successful conservation tool for many species, including New Zealandâs hihi (stitchbird, Notiomystis cincta). Previous research has shown supplementary feeding to substantially increase hihi reproductive success at regenerating forest sites, but suggested that it would have reduced benefit in mature forest habitat. Here we report the first direct test of the effect of supplementary feeding on hihi reproductive success in mature forest, using data from the recently reintroduced population at Maungatautari Ecological Island. Eight feeder-using females and nine non-feeder-using females were monitored during the 2012/13 breeding season at Maungatautari to determine how feeder use affected reproductive success (nest success, number of first-clutch fledglings per female and total number of fledglings per female). Feeder-using females fledged 3.7 times as many fledglings as non-feeder-using females in their first-clutch attempts (95% CI 1.6â8.8), and 1.8 times as many fledglings in total (95% CI 1.0â3.5). No feeder-using female experienced nest failure, whereas 7 of the 16 nest attempts of non-feeder-using females failed to fledge any young. The results suggest that, counter to expectations, supplementary feeder use has a significant impact on reproductive success in mature forest habitat. At least for Maungatautari, providing supplementary food in mature forest habitat appears to greatly reduce the probability of hihi nest failure, and increases the number of young a female can fledge
Behaviour in the hand predicts male natal dispersal distances in an establishing reintroduced hihi (Notiomystis cincta) population
Natal dispersal is a complex behaviour influenced by multiple factors that are often sex-specific and density-dependent. Reintroduced populations are typically low in density in the initial years of establishment; hence, understanding natal dispersal patterns in this context is a critical component of reintroduction biology. Natal dispersal is a key behaviour that influences both the probability of recruitment, and simultaneously dictates the spatial configuration of the reintroduced population as it establishes. Here, we examine natal dispersal in a reintroduced population of an endangered New Zealand forest passerine, the hihi, Notiomystis cincta, in the first 3 years after reintroduction to a large, mature forest reserve. We examined (1) differences between the sexes, and (2) the relationship between temperament and natal dispersal distances (NDD) in locally bred hihi over this time period. We found NDD varied widely in both sexes, with mean NDD significantly higher in males than females. There was a sex-specific effect of temperament, with males that distress-called during handling dispersing further than those that did not. Our results show that while clusters of individuals have established across the reserve due to conspecific attraction, there is movement between these clusters, primarily a consequence of dispersal of males of a distinct temperament. Continuing to monitor natal dispersal patterns as populations establish will provide further insights into the role of dispersal in shaping establishment patterns in reintroduced populations
A computational model of the hypothalamic - pituitary - gonadal axis in female fathead minnows (Pimephales promelas) exposed to 17α-ethynylestradiol and 17ÎČ-trenbolone
© 2011 Li et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.Background - Endocrine disrupting chemicals (e.g., estrogens, androgens and their mimics) are known to affect reproduction in fish. 17α-ethynylestradiol is a synthetic estrogen used in birth control pills. 17ÎČ-trenbolone is a relatively stable metabolite of trenbolone acetate, a synthetic androgen used as a growth promoter in livestock. Both 17α-ethynylestradiol and 17ÎČ-trenbolone have been found in the aquatic environment and affect fish reproduction. In this study, we developed a physiologically-based computational model for female fathead minnows (FHM, Pimephales promelas), a small fish species used in ecotoxicology, to simulate how estrogens (i.e., 17α-ethynylestradiol) or androgens (i.e., 17ÎČ-trenbolone) affect reproductive endpoints such as plasma concentrations of steroid hormones (e.g., 17ÎČ-estradiol and testosterone) and vitellogenin (a precursor to egg yolk proteins).
Results - Using Markov Chain Monte Carlo simulations, the model was calibrated with data from unexposed, 17α-ethynylestradiol-exposed, and 17ÎČ-trenbolone-exposed FHMs. Four Markov chains were simulated, and the chains for each calibrated model parameter (26 in total) converged within 20,000 iterations. With the converged parameter values, we evaluated the model's predictive ability by simulating a variety of independent experimental data. The model predictions agreed with the experimental data well.
Conclusions - The physiologically-based computational model represents the hypothalamic-pituitary-gonadal axis in adult female FHM robustly. The model is useful to estimate how estrogens (e.g., 17α-ethynylestradiol) or androgens (e.g., 17ÎČ-trenbolone) affect plasma concentrations of 17ÎČ-estradiol, testosterone and vitellogenin, which are important determinants of fecundity in fish.The Medical Research Foundation of Oregon, U.S. Environmental Protection
Agency, and the National Center for Computational Toxicology of the EPA Office of
Research and Development
Dark-adapted red flash ERGs in healthy adults
Purpose: The x-wave of the dark-adapted (DA) ERG to a red flash reflects DA cone function. This exploratory study of healthy adults aimed to investigate changes in the DA red ERG with flash strength and during dark adaptation to optimise visualisation and therefore quantification of the x-wave.
Methods: The effect of altering red flash strength was investigated in four subjects by recording ERGs after 20 minutes dark adaptation to red flashes (0.2â2.0 cd s m-2) using skin electrodes and natural pupils. The effect of dark adaptation duration was investigated in 16 subjects during 20 minutes in the dark, by recording DA 1.5 red ERGs at 1, 2, 3, 4, 5, 10, 15 and 20 minutes.
Results: For a dark adaption period of 20 minutes, the x-wave was more clearly visualised to weaker (< 0.6 cd s m-2) red flash strengths: to stronger flashes it became obscured by the b-wave. For red flashes of 1.5 cd s m-2, the x-wave was most prominent in ERGs recorded after 1â5 minutes of dark adaptation: with longer dark-adaptation, it was subsumed into the b-waveâs rising edge.
Conclusions: This small study suggests that x-wave visibility in healthy subjects after 20 minutes dark adaptation is improved by using flashes weaker than around 0.6 cd s m-2; for flash strengths of 1.5 cd s m-2, x-wave visibility is enhanced by recording after only around 5 minutes of dark adaptation. No evidence was found that interim red flash ERGs affecting the dark-adapted state of the normal retina
International Public Health Research Involving Interpreters: a Case Study from Bangladesh
Background: Cross-cultural and international research are important components of public health research, but the challenges of language barriers and working with interpreters are often overlooked, particularly in the case of qualitative research.
Methods: A case-study approach was used to explore experiences of working with an interpreter in Bangladesh as part of a research project investigating women's experiences of emergency obstetric care.
The case study: Data from the researcher's field notes provided evidence of experiences in working with an interpreter and show how the model of interviewing was adapted over time to give a more active role to the interpreter. The advantages of a more active role were increased rapport and "flow" in interviews. The disadvantages included reduced control from the researcher's perspective. Some tensions between the researcher and interpreter remained hard to overcome,
irrespective of the model used. Independent transcription and translation of the interviews also raised questions around accuracy in translation.
Conclusion: The issues examined in this case study have broader implications for public health research. Further work is needed in three areas: 1) developing effective relationships with interpreters; 2) the impact of the interpreter on the research process; and 3) the accuracy of the translation and level of analysis needed in any specific public health research. Finally, this paper highlights the importance to authors of reflecting on the potential impact of translation and interpretation on the research process when disseminating their research
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Genetic variation in the HLA region is associated with susceptibility to herpes zoster.
Herpes zoster, commonly referred to as shingles, is caused by the varicella zoster virus (VZV). VZV initially manifests as chicken pox, most commonly in childhood, can remain asymptomatically latent in nerve tissues for many years and often re-emerges as shingles. Although reactivation may be related to immune suppression, aging and female sex, most inter-individual variability in re-emergence risk has not been explained to date. We performed a genome-wide association analyses in 22,981 participants (2280 shingles cases) from the electronic Medical Records and Genomics Network. Using Cox survival and logistic regression, we identified a genomic region in the combined and European ancestry groups that has an age of onset effect reaching genome-wide significance (P>1.0 Ă 10(-8)). This region tags the non-coding gene HCP5 (HLA Complex P5) in the major histocompatibility complex. This gene is an endogenous retrovirus and likely influences viral activity through regulatory functions. Variants in this genetic region are known to be associated with delay in development of AIDS in people infected by HIV. Our study provides further suggestion that this region may have a critical role in viral suppression and could potentially harbor a clinically actionable variant for the shingles vaccine
iCanPlot: Visual Exploration of High-Throughput Omics Data Using Interactive Canvas Plotting
Increasing use of high throughput genomic scale assays requires effective visualization and analysis techniques to facilitate data interpretation. Moreover, existing tools often require programming skills, which discourages bench scientists from examining their own data. We have created iCanPlot, a compelling platform for visual data exploration based on the latest technologies. Using the recently adopted HTML5 Canvas element, we have developed a highly interactive tool to visualize tabular data and identify interesting patterns in an intuitive fashion without the need of any specialized computing skills. A module for geneset overlap analysis has been implemented on the Google App Engine platform: when the user selects a region of interest in the plot, the genes in the region are analyzed on the fly. The visualization and analysis are amalgamated for a seamless experience. Further, users can easily upload their data for analysisâwhich also makes it simple to share the analysis with collaborators. We illustrate the power of iCanPlot by showing an example of how it can be used to interpret histone modifications in the context of gene expression
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