817 research outputs found
Understanding species - level primate diversity in Madagascar
Over the past couple of decades Madagascar has witnessed an explosion in the number of primate species generally recognized. Much of this proliferation can be traced less to increasing knowledge of the lemur fauna than to the complete replacement of biological notions of the species by the Phylogenetic Species Concept (PSC), which views species as irreducible diagnosable units. The consequent focus on autapomorphy (unique possession of morphological and molecular derived features) as ‘the’ criterion for species recognition has led to the almost complete disappearance of lemur subspecies from Madagascar faunal lists; yet subspecies are an expected result of the evolutionary forces that gave rise to the island’s current pattern of biodiversity. Thanks in part to the perspective introduced by the PSC, it has become clear both that there is much more species - level diversity among Madagascar’s lemurs than was evident only a couple of decades ago, and that this diversity is much more complexly structured than we had thought. But it does not appear to be aptly reflected in the hard - line procedural adoption of the PSC across the board, a move that typically results in fifty-percent inflation in species numbers relative to those yielded by biological concepts. I argue here that the reflexive wholesale application of the PSC to Madagascar’s lemurs is inappropriate from both systematic and conservation standpoints, and that a return to biological species concepts, and to the corresponding criteria for species recognition, will allow us to attain a much fuller and more nuanced appreciation of lemur diversity at low taxonomic levels
Doctors behaving badly?
It is in doctors’ and the drug industry’s best interests that their interactions be openly declared. There is no such thing as a free lunch. Pharmaceutical companies lavish meals, five-star travel, cash and gifts on doctors for one reason: to encourage them to prescribe their drugs. The standard retort from the medical profession is that doctors have sufficient clinical objectivity — and personal integrity — not to be so crudely swayed. Perhaps s
Parallel multicentre randomised trial of a clinical trial question prompt list in patients considering participation in phase 3 cancer treatment trials
Accepted 9 February 2017Objective: To evaluate the effect of a clinical trial question prompt list in patients considering enrolment in cancer treatment trials. Setting: Tertiary cancer referral hospitals in three state capital cities in Australia. Participants: 88 patients with cancer attending three cancer centres in Australia, who were considering enrolment in phase 3 treatment trials, were invited to enrol in an unblinded randomised trial of provision of a clinical trial question prompt list (QPL) before consenting to enrol in the treatment trial. Interventions: We developed and pilot tested a targeted QPL for patients with cancer considering clinical trial participation (the clinical trial QPL). Consenting patients were randomised to receive the clinical trial QPL or not before further discussion with their oncologist and/or trial nurse about the treatment trial. Primary and secondary outcomes: Questionnaires were completed at baseline and within 3â €..weeks of deciding on treatment trial participation. Main outcome measure: scores on the Quality of Informed Consent questionnaire (QuIC). Results: 88 patients of 130 sought for the study were enrolled (43 males), and 45 received the clinical trial QPL. 49% of trials were chemotherapy interventions for patients with advanced disease, 35% and 16% were surgical adjuvant and radiation adjuvant trials respectively. 70 patients completed all relevant questionnaires. 28 of 43 patients in the control arm compared with 39 of 45 patients receiving the clinical trial QPL completed the QuIC (p=0.0124). There were no significant differences in the QuIC scores between the randomised groups (QuIC part A p=0.08 and QuIC part B p=0.92). There were no differences in patient satisfaction with decisions or in anxiety levels between the randomised groups. Conclusions: Use of a question prompt list did not significantly change the QuIC scores in this randomised trial. ANZCTR 12606000214538 prospectively registered 31/5/2006. Trial registration number: Results, ACTRN12606000214538.Martin H N Tattersall, Michael Jefford, Andrew Martin, Ian Olver, John F Thompson, Richard F Brown, Phyllis N Buto
Can a single image processing algorithm work equally well across all phases of DCE-MRI?
Image segmentation and registration are said to be challenging when applied
to dynamic contrast enhanced MRI sequences (DCE-MRI). The contrast agent causes
rapid changes in intensity in the region of interest and elsewhere, which can
lead to false positive predictions for segmentation tasks and confound the
image registration similarity metric. While it is widely assumed that contrast
changes increase the difficulty of these tasks, to our knowledge no work has
quantified these effects. In this paper we examine the effect of training with
different ratios of contrast enhanced (CE) data on two popular tasks:
segmentation with nnU-Net and Mask R-CNN and registration using VoxelMorph and
VTN. We experimented further by strategically using the available datasets
through pretraining and fine tuning with different splits of data. We found
that to create a generalisable model, pretraining with CE data and fine tuning
with non-CE data gave the best result. This interesting find could be expanded
to other deep learning based image processing tasks with DCE-MRI and provide
significant improvements to the models performance
Auto-calibration of ultrasonic lubricant-film thickness measurements
The measurement of oil film thickness in a lubricated component is essential information for performance monitoring and design. It is well established that such measurements can be made ultrasonically if the lubricant film is modelled as a collection of small springs. The ultrasonic method requires that component faces are separated and a reference reflection recorded in order to obtain a reflection coefficient value from which film thickness is calculated. The novel and practically useful approach put forward in this paper and validated experimentally allows reflection coefficient measurement without the requirement for a reference. This involves simultaneously measuring the amplitude and phase of an ultrasonic pulse reflected from a layer. Provided that the acoustic properties of the substrate are known, the theoretical relationship between the two can be fitted to the data in order to yield reflection coefficient amplitude and phase for an infinitely thick layer. This is equivalent to measuring a reference signal directly, but importantly does not require the materials to be separated. The further valuable aspect of this approach, which is demonstrated experimentally, is its ability to be used as a self-calibrating routine, inherently compensating for temperature effects. This is due to the relationship between the amplitude and phase being unaffected by changes in temperature which cause unwanted changes to the incident pulse. Finally, error analysis is performed showing how the accuracy of the results can be optimized. A finding of particular significance is the strong dependence of the accuracy of the technique on the amplitude of reflection coefficient input data used. This places some limitations on the applicability of the technique. © 2008 IOP Publishing Ltd
Lemur Systematics and Hemoglobin Phylogeny a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73526/1/j.1749-6632.1988.tb51443.x.pd
Achieving equal standards in medical student education: is a national exit examination the answer?
The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Although it is commonly assumed that the quality of medical school education in Australia is uniformly high, there is no national process for assessing its outcomes. There is substantial variability in the content of medical school curricula, and the process of curriculum change is becoming more challenging because of intense competition for time and space in the course. A national exit examination could provide a uniform standard of assessment for all medical school graduates in Australia, as well as foreign graduates applying to work in Australia. Such an examination could assess medical school outcomes, monitor the effects of curriculum change, and provide a benchmark for new medical schools that would help medical curricula evolve to better meet society’s needs.Bogda Koczwara, Martin H N Tattersall, Michael B Barton, Brendon J Coventry, Joanna M Dewar, Jeremy L Millar, Ian N Olver, Max A Schwarz, Darren L Starmer, David R Turner and Martin R Stockler, for the Cancer Council of Australia Oncology Education Committe
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