6 research outputs found

    Foraging under Predation Risk: A test of giving-up densities with samango monkeys in South Africa

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    Animals frequently make a trade-off between food and safety and will sacrifice feeding effort if it means safety from predators. A forager can also vary its vigilance levels to manage predation risk. Giving-up densities (GUDs), the amount of food items left once a forager has quit an experimental food patch, have been used extensively as measures of foraging behaviour under risk of predation in a wide range of species. Vigilance also serves as an anti-predatory response to predation risk and has been the focus of a range of behavioural studies. However, very few studies have looked at these two measures together. The principal aim of this study was to determine the effect of habitat factors on the foraging behaviour of samango monkeys (Cercopithcus mitis erythrarchus) by measuring GUDs in artificial food patches and foraging behaviour, and relating this to height from the ground, canopy cover, habitat visibility and observed behaviour. The second objective was then to determine the extent to which the experimental approach matched observed behaviour in measuring primate responses to predation risk. The monkeys revealed lower GUDs with increasing height and with decreasing canopy cover and but were not affected by habitat visibility. Vigilance varied considerably with only conspecific and observer vigilance showing significant effects. Conspecific vigilance increased with height and decreasing canopy cover. Vigilance directed at observers increased with decreasing canopy cover. There was no effect of habitat visibility on any of the component behaviours of vigilance. The vigilance behaviour of the monkeys did not completely compliment the GUD results. The findings of this study confirm the prediction that habitat plays a key role in the foraging behaviour of samango monkeys but that vigilance is more sensitive to other factors such as sociality. Further work is required to determine the extent to which experimental approaches based on giving up densities match patterns of antipredatory behaviour recorded by observational methods

    The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

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    Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

    Signing on the tactile line: a multimodal system for teaching handwriting to blind children

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    We present McSig, a multimodal system for teaching blind children cursive handwriting so that they can create a personal signature. For blind people handwriting is very difficult to learn as it is a near-zero feedback activity that is needed only occasionally, yet in important situations; for example, to make an attractive and repeatable signature for legal contracts. McSig aids the teaching of signatures by translating digital ink from the teacher's stylus gestures into three non-visual forms: (1) audio pan and pitch represents the x and y movement of the stylus; (2) kinaesthetic information is provided to the student through a force-feedback haptic pen that mimics the teacher's stylus movement; and (3) a physical tactile line on the writing sheet is created by the haptic pen. McSig has been developed over two major iterations of design, usability testing and evaluation. The final step of the first iteration was a short evaluation with eight visually impaired children. The results suggested that McSig had the highest potential benefit for congenitally and totally blind children and also indicated some areas where McSig could be enhanced. The second prototype incorporated significant modifications to the system, improving the audio, tactile and force-feedback. We then ran a detailed, longitudinal evaluation over 14 weeks with three of the congenitally blind children to assess McSig's effectiveness in teaching the creation of signatures. Results demonstrated the effectiveness of McSig—they all made considerable progress in learning to create a recognizable signature. By the end of ten lessons, two of the children could form a complete, repeatable signature unaided, the third could do so with a little verbal prompting. Furthermore, during this project, we have learnt valuable lessons about providing consistent feedback between different communications channels (by manual interactions, haptic device, pen correction) that will be of interest to others developing multimodal sys

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