7440 research outputs found
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Body mass-corrected molecular rate for bird mitochondrial DNA
No full textMitochondrial DNA remains one of the most widely used molecular markers to reconstruct the phylogeny and phylogeography of closely related birds. It has been proposed that bird mitochondrial genomes evolve at a constant rate of ~0.01 substitution per site per million years, that is that they evolve according to a strict molecular clock. This molecular clock is often used in studies of bird mitochondrial phylogeny and molecular dating. However, rates of mitochondrial genome evolution vary among bird species and correlate with life history traits such as body mass and generation time. These correlations could cause systematic biases in molecular dating studies that assume a strict molecular clock. In this study, we overcome this issue by estimating corrected molecular rates for birds. Using complete or nearly complete mitochondrial genomes of 475 species, we show that there are strong relationships between body mass and substitution rates across birds. We use this information to build models that use bird species' body mass to estimate their substitution rates across a wide range of common mitochondrial markers. We demonstrate the use of these corrected molecular rates on two recently published data sets. In one case, we obtained molecular dates that are twice as old as the estimates obtained using the strict molecular clock. We hope that this method to estimate molecular rates will increase the accuracy of future molecular dating studies in birds.12 page(s
Nanofibril scaffold assisted MEMS artificial hydrogel neuromasts for enhanced sensitivity flow sensing
No full textWe present the development and testing of superficial neuromast-inspired flow sensors that also attain high sensitivity and resolution through a biomimetic hyaulronic acid-based hydrogel cupula dressing. The inspiration comes from the spatially distributed neuromasts of the blind cavefish that live in completely dark undersea caves; the sensors enable the fish to form three-dimensional flow and object maps, enabling them to maneuver efficiently in cluttered environments. A canopy shaped electrospun nanofibril scaffold, inspired by the cupular fibrils, assists the drop-casting process allowing the formation of a prolate spheroid-shaped artificial cupula. Rheological and nanoindentation characterizations showed that the Young’s modulus of the artificial cupula closely matches the biological cupula (10–100 Pa). A comparative experimental study conducted to evaluate the sensitivities of the naked hair cell sensor and the cupula-dressed sensor in sensing steady-state flows demonstrated a sensitivity enhancement by 3.5–5 times due to the presence of hydrogel cupula. The novel strategies of sensor development presented in this report are applicable to the design and fabrication of other biomimetic sensors as well. The developed sensors can be used in the navigation and maneuvering of underwater robots, but can also find applications in biomedical and microfluidic devices.12 page(s
Student perspectives on data provision and use : starting to unpack disciplinary differences
No full textHow can we best align learning analytics practices with disciplinary knowledge practices in order to support student learning? Although learning analytics itself is an interdisciplinary field, it tends to take a 'one-size-fits-all' approach to the collection, measurement, and reporting of data, overlooking disciplinary knowledge practices. In line with a recent trend in higher education research, this paper considers the contribution of a realist sociology of education to the field of learning analytics, drawing on findings from recent student focus groups at an Australian university. It examines what learners say about their data needs with reference to organizing principles underlying knowledge practices within their disciplines. The key contribution of this paper is a framework that could be used as the basis for aligning the provision and/or use of data in relation to curriculum, pedagogy, and assessment with disciplinary knowledge practices. The framework extends recent research in Legitimation Code Theory, which understands disciplinary differences in terms of the principles that underpin knowledge-building. The preliminary analysis presented here both provides a tool for ensuring a fit between learning analytics practices and disciplinary practices and standards for achievement, and signals disciplinarity as an important consideration in learning analytics practices.10 page(s
The influence of health-specific social network site use on the psychological well-being of cancer-affected people
No full textObjective We aimed to explore and examine how and in what ways the use of social network sites (SNSs) can improve health outcomes, specifi- cally better psychological well-being, for cancer-affected people. Methods Qualitative semi-structured interviews were conducted with users of the Ovarian Cancer Australia Facebook page (OCA Facebook), the ex- emplar SNS used in this study. Twenty-five women affected by ovarian cancer who were users of OCA Facebook were interviewed. A multi-theory perspective was employed to interpret the data. Results Most of the study participants used OCA Facebook daily. Some users were passive and only observed created content, while other users actively posted content and communicated with other members. Analysis showed that the use of this SNS enhanced social support for users, improved the users' experiences of social connectedness, and helped users learn and develop social presence, which ultimately improved their psy- chological well-being. Discussion The strong theoretical underpinning of our research and empirically derived results led to a new understanding of the capacity of SNSs to improve psychological well-being. Our study provides evidence showing how the integration of these tools into existing health services can enhance patients' psychological well-being. This study also contributes to the body of knowledge on the implications of SNS use for improving the psychological well-being of cancer-affected people. Conclusion This research assessed the relationship between the use of SNSs, specifically OCA Facebook, and the psychological well-being of cancer-affected people. The study confirmed that using OCA Facebook can improve psychological well-being by demonstrating the potential value of SNSs as a support service in the healthcare industry.10 page(s
We need to know more about providing effective support for communication partners of children who use augmentative and alternative communication
No full textThis review provides a summary and appraisal commentary on the treatment review by Shire, S. Y., & Jones, N. (2015). Communication partners supporting children with complex communication needs who use AAC: A systematic review. Communication Disorders Quarterly, 37, 3–15. doi: 10.1177/1525740114558254 Source of funding and declaration of interests: The first author received fellowship funds from the Canadian Institutes of Health Research (Doctoral Foreign Study Award) and Autism Speaks (Weatherstone Pre-Doctoral Fellowship). The authors reported no potential conflicts of interest.6 page(s
Versatile application of fluorescent quantum dot labels in super-resolution fluorescence microscopy
No full textQuantum dots (QDs) are well known as bright and photostable inorganic fluorescent probes for microscopy imaging, with many attractive features superior to those found in organic dyes. However, their broadband excitation spectrum and emission blinking property have limited the applicability of QDs in modern super-resolution microscopy techniques. In this work, we systematically investigate practical approaches to overcoming these drawbacks and provide examples of their use across many commercially available super-resolution microscopy systems now accessible to biologists, with examples across the major super-resolution techniques. This work further maps out how QDs can be further engineered to facilitate their applications in the respective super-resolution microscopy techniques.8 page(s
Seeing yellow : 'connection' and routine in professional musicians' experience of music performance
No full textWhat is it like for a professional musician to perform music in front of a live audience? We use Strauss and Corbin’s (1998) Grounded Theory to conduct qualitative research with 10 professional musicians to investigate their experience of music performance. We find performance to extend temporally beyond time spent before an audience and to include performers’ rituals of separation from everyday life. Using the abridged version of the model emerging from this data that we present in this article, we investigate how professional musicians’ experience of music performance centers on forging ‘connection’ with an audience and the ways in which this process is facilitated by the pre- and post-performance routines in which musicians engage. We find musicians’ understandings and experiences of ‘connection’ during performance to differ greatly, being influenced by their positioning on two spectra that emerge in this study and indicate the extent to which, during performance, musicians: a) value attentiveness and/or attunement in an audience and b) are open to variability.19 page(s
