Publications by authors named "Libby Thomas"

20 Publications

  • Page 1 of 1

Inside The O2: the NHS Nightingale Hospital London education center.

J Interprof Care 2020 Sep-Oct;34(5):698-701. Epub 2020 Sep 29.

Health Education England , London, England.

As part of the response to COVID-19 in the United Kingdom (UK) the NHS Nightingale Hospital London was rapidly established in March 2020. Set up in the ExCel, an international conference center, it aimed to address the anticipated shortfall of intensive care beds in London. Whilst this hospital garnered huge amounts of publicity in the UK, less widely discussed is the Nightingale Education Center. The education center was instrumental in ensuring that there were staff across all professions ready to work there and had interprofessional education at its core. In a period of under two months it inducted and upskilled over 2,500 people from multiple healthcare and non-healthcare professions. That is more than most hospitals would induct in a whole year. To complete interprofessional training on this scale the education center decamped from the ExCel to The O2, a 20,000 capacity arena, and remained there for six weeks beating the iconic artist Prince for the title of longest running residency. This report offers a reflection on the authors' time spent working in the Education Center as members of the 'Core Operations' team. The content of the article is based upon the authors' reflections, first-hand experiences and field observations. It offers a reflection upon the massive undertaking of setting up an education center in an entertainment venue, as well as the successes and challenges of working interprofessionally in this unique space and under pandemic conditions.
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http://dx.doi.org/10.1080/13561820.2020.1823949DOI Listing
November 2020

The use of simulation to prepare and improve responses to infectious disease outbreaks like COVID-19: practical tips and resources from Norway, Denmark, and the UK.

Adv Simul (Lond) 2020 16;5. Epub 2020 Apr 16.

1Department of Quality and Health Technology, Faculty of Health Sciences, University of Stavanger, Stavanger, Norway.

In this paper, we describe the potential of simulation to improve hospital responses to the COVID-19 crisis. We provide tools which can be used to analyse the current needs of the situation, explain how simulation can help to improve responses to the crisis, what the key issues are with integrating simulation into organisations, and what to focus on when conducting simulations. We provide an overview of helpful resources and a collection of scenarios and support for centre-based and in situ simulations.
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http://dx.doi.org/10.1186/s41077-020-00121-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7160610PMC
April 2020

History-dependent perturbation response in limb muscle.

J Exp Biol 2020 01 6;223(Pt 1). Epub 2020 Jan 6.

School of Physics and School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA

Muscle mediates movement but movement is typically unsteady and perturbed. Muscle is known to behave non-linearly and with history-dependent properties during steady locomotion, but the importance of history dependence in mediating muscle function during perturbations remains less clear. To explore the capacity of muscles to mitigate perturbations during locomotion, we constructed a series of perturbations that varied only in kinematic history, keeping instantaneous position, velocity and time from stimulation constant. We found that the response of muscle to a perturbation is profoundly history dependent, varying 4-fold as baseline frequency changes, and dissipating energy equivalent to ∼6 times the kinetic energy of all the limbs in 5 ms (nearly 2400 W kg). Muscle energy dissipation during a perturbation is predicted primarily by the force at the onset of the perturbation. This relationship holds across different frequencies and timings of stimulation. This history dependence behaves like a viscoelastic memory producing perturbation responses that vary with the frequency of the underlying movement.
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http://dx.doi.org/10.1242/jeb.199018DOI Listing
January 2020

Geckos Race Across the Water's Surface Using Multiple Mechanisms.

Curr Biol 2018 12 6;28(24):4046-4051.e2. Epub 2018 Dec 6.

Department of Integrative Biology, University of California, Berkeley, Valley Life Sciences Building, Berkeley, CA 94720, USA. Electronic address:

Acrobatic geckos can sprint at high speeds over challenging terrain [1], scamper up the smoothest surfaces [2], rapidly swing underneath leaves [3], and right themselves in midair by swinging only their tails [4, 5]. From our field observations, we can add racing on the water's surface to the gecko's list of agile feats. Locomotion at the air-water interface evolved in over a thousand species, including insects, fish, reptiles, and mammals [6]. To support their weight, some larger-legged vertebrates use forces generated by vigorous slapping of the fluid's surface followed by a stroke of their appendage [7-12], whereas smaller animals, like arthropods, rely on surface tension to walk on water [6, 13]. Intermediate-sized geckos (Hemidactylus platyurus) fall squarely between these two regimes. Here, we report the unique ability of geckos to exceed the speed limits of conventional surface swimming. Several mechanisms likely contribute in this intermediate regime. In contrast to bipedal basilisk lizards [7-10], geckos used a stereotypic trotting gait with all four limbs, creating air cavities during slapping to raise their head and anterior trunk above water. Adding surfactant to the water decreased velocity by half, confirming surface tension's role. The superhydrophobic skin could reduce drag during semi-planing. Geckos laterally undulated their bodies, including their submerged posterior trunk and tail, generating thrust for forward propulsion, much like water dragons [14] and alligators [15]. Geckos again remind us of the advantages of multi-functional morphologies providing the opportunity for multiple mechanisms for motion.
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http://dx.doi.org/10.1016/j.cub.2018.10.064DOI Listing
December 2018

Interdisciplinary Laboratory Course Facilitating Knowledge Integration, Mutualistic Teaming, and Original Discovery.

Integr Comp Biol 2015 Nov 3;55(5):912-25. Epub 2015 Aug 3.

Department of Integrative Biology, University of California, Berkeley, CA 94720-3140, USA.

Experiencing the thrill of an original scientific discovery can be transformative to students unsure about becoming a scientist, yet few courses offer authentic research experiences. Increasingly, cutting-edge discoveries require an interdisciplinary approach not offered in current departmental-based courses. Here, we describe a one-semester, learning laboratory course on organismal biomechanics offered at our large research university that enables interdisciplinary teams of students from biology and engineering to grow intellectually, collaborate effectively, and make original discoveries. To attain this goal, we avoid traditional "cookbook" laboratories by training 20 students to use a dozen research stations. Teams of five students rotate to a new station each week where a professor, graduate student, and/or team member assists in the use of equipment, guides students through stages of critical thinking, encourages interdisciplinary collaboration, and moves them toward authentic discovery. Weekly discussion sections that involve the entire class offer exchange of discipline-specific knowledge, advice on experimental design, methods of collecting and analyzing data, a statistics primer, and best practices for writing and presenting scientific papers. The building of skills in concert with weekly guided inquiry facilitates original discovery via a final research project that can be presented at a national meeting or published in a scientific journal.
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http://dx.doi.org/10.1093/icb/icv095DOI Listing
November 2015

'The Diamond': a structure for simulation debrief.

Clin Teach 2015 Jun;12(3):171-5

King's Learning Institute, King's College London, UK.

Background: Despite debriefing being found to be the most important element in providing effective learning in simulation-based medical education reviews, there are only a few examples in the literature to help guide a debriefer. The diamond debriefing method is based on the technique of description, analysis and application, along with aspects of the advocacy-inquiry approach and of debriefing with good judgement. It is specifically designed to allow an exploration of the non-technical aspects of a simulated scenario.

Context: The debrief diamond, a structured visual reminder of the debrief process, was developed through teaching simulation debriefing to hundreds of faculty members over several years. The diamond shape visually represents the idealised process of a debrief: opening out a facilitated discussion about the scenario, before bringing the learning back into sharp focus with specific learning points. Debriefing is the most important element in providing effective learning in simulation-based medical education reviews

Innovation: The Diamond is a two-sided prompt sheet: the first contains the scaffolding, with a series of specifically constructed questions for each phase of the debrief; the second lays out the theory behind the questions and the process.

Implication: The Diamond encourages a standardised approach to high-quality debriefing on non-technical skills. Feedback from learners and from debriefing faculty members has indicated that the Diamond is useful and valuable as a debriefing tool, benefiting both participants and faculty members. It can be used by junior and senior faculty members debriefing in pairs, allowing the junior faculty member to conduct the description phase, while the more experienced faculty member leads the later and more challenging phases. The Diamond gives an easy but pedagogically sound structure to follow and specific prompts to use in the moment.
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http://dx.doi.org/10.1111/tct.12300DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4497353PMC
June 2015

Sociological fidelity: keeping the patient at the heart of interprofessional learning.

J Interprof Care 2015 May;29(3):177-8

Division of Medical Education, Kings College London , London , UK and.

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http://dx.doi.org/10.3109/13561820.2015.1035179DOI Listing
May 2015

Stress distribution and contact area measurements of a gecko toe using a high-resolution tactile sensor.

Bioinspir Biomim 2015 Feb 2;10(1):016013. Epub 2015 Feb 2.

Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.

The adhesive systems of geckos have been widely studied and have been a great source of bioinspiration. Load-sharing (i.e. preventing stress concentrations through equal distribution of loads) is necessary to maximize the performance of an adhesive system, but it is not known to what extent load-sharing occurs in gecko toes. In this paper, we present in vivo measurements of the stress distribution and contact area on the toes of a tokay gecko (Gekko gecko) using a custom tactile sensor with 100 μm spatial resolution. We found that the stress distributions were nonuniform, with large variations in stress between and within lamellae, suggesting that load-sharing in the tokay gecko is uneven. These results may be relevant to the understanding of gecko morphology and the design of improved synthetic adhesive systems.
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http://dx.doi.org/10.1088/1748-3190/10/1/016013DOI Listing
February 2015

Development of a tool to improve performance debriefing and learning: the paediatric Objective Structured Assessment of Debriefing (OSAD) tool.

Postgrad Med J 2014 Nov 8;90(1069):613-21. Epub 2014 Sep 8.

Department of Surgery and Cancer, Imperial College, London, UK.

Background: Simulation is an important educational tool to improve medical training and patient safety. Debriefing after simulation is crucial to maximise learning and to translate the lessons learnt to improve real clinical performance, and thus to reduce medical error. Currently there are few tools to improve performance debriefing and learning after simulations of serious paediatric situations.

Purpose: The purpose of this study was to develop a tool to guide and assess debriefings after simulations of serious paediatric situations, applying the current evidence base and user-based research.

Study Design: A literature review and semistructured interviews (performed in 2010) to identify important features of a paediatric simulation debriefing. Emergent theme analysis was used to identify key components of an effective debriefing which could be used as a tool for assessing debriefing effectiveness.

Results: The literature review identified 34 relevant studies. Interviews were carried out with 16 paediatricians, both debriefing facilitators and learners. In total, 307 features of a debriefing were identified. These were grouped into eight dimensions representing the key components of a paediatric debriefing: the facilitator's approach, learning environment, engagement of learners, reaction, descriptive reflection, analysis, diagnosis and application. These eight dimensions were used to create a tool, the Objective Structured Assessment of Debriefing (OSAD). Each dimension can be scored on a five-point Likert scale containing descriptions for scores 1, 3 and 5 to serve as anchors and aid scoring.

Conclusions: The study identified the important features of a paediatric simulation debriefing, which were developed into the OSAD tool. OSAD offers a structured approach to paediatric simulation debriefing, and is based on evidence from published literature and views of simulation facilitators and learners. OSAD may be used as a guide or assessment tool to improve the quality of debriefing after paediatric simulation.
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http://dx.doi.org/10.1136/postgradmedj-2012-131676DOI Listing
November 2014

Surgical correction of excessive gingival display in class I vertical maxillary excess: Mucosal strip technique.

J Nat Sci Biol Med 2014 Jul;5(2):494-8

Department of Periodontics, Meenakshi Ammal Dental College and Hospital, Chennai, India.

There are several conditions that results in excessive gingival display. In case of class I vertical maxillary excess the reason for this excessive display is the hypermobile lip. Though orthodontic treatment is the choice of treatment, surgical repositioning along with the orthodontics gives more predictable and stable results. This case report discusses cosmetic surgical management of case with class I vertical maxillary excess with excessive gingival display. The technique involves removal of strip of mucosal tissue from the labial vestibule thereby limiting the retraction of elevator muscles.
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http://dx.doi.org/10.4103/0976-9668.136290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4121947PMC
July 2014

Short-term effects of nonsurgical periodontal treatment with and without use of diode laser (980 nm) on serum levels of reactive oxygen metabolites and clinical periodontal parameters in patients with chronic periodontitis: a randomized controlled trial.

Quintessence Int 2014 Mar;45(3):193-201

Objective: The aim of this study was to compare the clinical efficiency of a diode laser as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis patients, and also to evaluate the changes in the clinical parameters such as clinical attachment level in teeth with periodontal pockets and blood reactive oxygen metabolites.

Method And Materials: A total of thirty patients (mean age 38.2 years) with chronic periodontitis were selected for this study. The patients were randomly assigned into two groups of 15 patients each, as the control group and test group. The control group received only conventional SRP and the test group received conventional SRP and diode laser (GaAlAs)-assisted pocket debridement. The clinical parameters (Plaque Index, bleeding on probing, probing pocket depth, and clinical attachment level) were recorded at baseline and day 60, and the serum levels of reactive oxygen metabolites were estimated at baseline, day 30, and day 60 for both the groups.

Results: When the groups were compared, there was statistically significant improvement in Plaque Index score, decrease in bleeding on probing and probing pocket depth, and gain in clinical attachment level (P < .001) in both the groups from baseline to day 60. There was significant reduction in reactive oxygen metabolites in both the groups from baseline to day 30 and day 60 (P < .001). However no statistically significant changes were present between the treatment groups from baseline to day 60 in terms of clinical parameters and blood reactive oxygen metabolites.

Conclusion: From the results observed in this study it can be concluded that use of diode laser as an adjunct to SRP did not provide any significant difference compared to use of SRP alone in terms of clinical parameters and reactive oxygen metabolites.
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http://dx.doi.org/10.3290/j.qi.a31206DOI Listing
March 2014

A comparative clinical study of the efficacy of subepithelial connective tissue graft and acellular dermal matrix graft in root coverage: 6-month follow-up observation.

J Indian Soc Periodontol 2013 Jul;17(4):478-83

Department of Periodontology and Implantology, Meenakshiammal Dental College and Hospital, Alapakkam Main Road, Maduravoyal, Chennai, Tamil Nadu, India.

Aims: The purpose of this study was to compare the clinical efficacy of subepithelial connective tissue graft and acellular dermal matrix graft associated with coronally repositioned flap in the treatment of Miller's class I and II gingival recession, 6 months postoperatively.

Settings And Design: Ten patients with bilateral Miller's class I or class II gingival recession were randomly divided into two groups using a split-mouth study design.

Materials And Methods: Group I (10 sites) was treated with subepithelial connective tissue graft along with coronally repositioned flap and Group II (10 sites) treated with acellular dermal matrix graft along with coronally repositioned flap. Clinical parameters like recession height and width, probing pocket depth, clinical attachment level, and width of keratinized gingiva were evaluated at baseline, 90(th) day, and 180(th) day for both groups. The percentage of root coverage was calculated based on the comparison of the recession height from 0 to 180(th) day in both Groups I and II.

Statistical Analysis Used: Intragroup parameters at different time points were measured using the Wilcoxon signed rank test and Mann-Whitney U test was employed to analyze the differences between test and control groups.

Results: There was no statistically significant difference in recession height and width, gain in CAL, and increase in the width of keratinized gingiva between the two groups on the 180(th) day. Both procedures showed clinically and statistically significant root coverage (Group I 96%, Group II 89.1%) on the 180(th) day.

Conclusions: The results indicate that coverage of denuded root with both subepithelial connective tissue autograft and acellular dermal matrix allograft are very predictable procedures, which were stable for 6 months postoperatively.
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http://dx.doi.org/10.4103/0972-124X.118320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3800411PMC
July 2013

Peri-implant esthetics assessment and management.

Dent Res J (Isfahan) 2013 Jan;10(1):7-14

Department of Periodontology, Meenakshi Ammal Dental College, Alapakkam Main Road, Maduravoyal, Chennai, Tamil Nadu, India.

Providing an esthetic restoration in the anterior region of the mouth has been the basis of peri-implant esthetics. To achieve optimal esthetics, in implant supported restorations, various patient and tooth related factors have to be taken into consideration. Peri-implant plastic surgery has been adopted to improve the soft tissue and hard tissue profiles, during and after implant placement. The various factors and the procedures related to enhancement of peri-implant esthetics have been discussed in this review article.
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http://dx.doi.org/10.4103/1735-3327.111757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3714827PMC
January 2013

Simulation training for improving the quality of care for older people: an independent evaluation of an innovative programme for inter-professional education.

BMJ Qual Saf 2013 Jun 6;22(6):495-505. Epub 2012 Dec 6.

Simulation and Interactive Learning (SaIL) Centre, St Thomas' Hospital, King's Health Partners, London, UK.

Introduction: This paper describes the evaluation of a 2-day simulation training programme for staff designed to improve teamwork and inpatient care and compassion in an older persons' unit.

Objective: The programme was designed to improve inpatient care for older people by using mixed modality simulation exercises to enhance teamwork and empathetic and compassionate care.

Methods: Healthcare professionals took part in: (a) a 1-day human patient simulation course with six scenarios and (b) a 1-day ward-based simulation course involving five 1-h exercises with integrated debriefing. A mixed methods evaluation included observations of the programme, precourse and postcourse confidence rating scales and follow-up interviews with staff at 7-9 weeks post-training.

Results: Observations showed enjoyment of the course but some anxiety and apprehension about the simulation environment. Staff self-confidence improved after human patient simulation (t=9; df=56; p<0.001) and ward-based exercises (t=9.3; df=76; p<0.001). Thematic analysis of interview data showed learning in teamwork and patient care. Participants thought that simulation had been beneficial for team practices such as calling for help and verbalising concerns and for improved interaction with patients. Areas to address in future include widening participation across multi-disciplinary teams, enhancing post-training support and exploring further which aspects of the programme enhance compassion and care of older persons.

Conclusions: The study demonstrated that simulation is an effective method for encouraging dignified care and compassion for older persons by teaching team skills and empathetic and sensitive communication with patients and relatives.
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http://dx.doi.org/10.1136/bmjqs-2012-000954DOI Listing
June 2013

Development and implementation of centralized simulation training: evaluation of feasibility, acceptability and construct validity.

BJU Int 2013 Mar 29;111(3):518-23. Epub 2012 Aug 29.

MRC Centre for Transplantation, King's College London, King's Health Partners, Department of Urology, Guy's Hospital, London, UK.

Unlabelled: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: A competent urologist should not only have effective technical skills, but also other attributes that would make him/her a complete surgeon. These include team-working, communication and decision-making skills. Although evidence for effectiveness of simulation exists for individual simulators, there is a paucity of evidence for utility and effectiveness of these simulators in training programmes that aims to combine technical and non-technical skills training. This article explains the process of development and validation of a centrally coordinated simulation program (Participants - South-East Region Specialist Registrars) under the umbrella of the British Association for Urological Surgeons (BAUS) and the London Deanery. This program incorporated training of both technical (synthetic, animal and virtual reality models) and non-technical skills (simulated operating theatres).

Objectives: To establish the feasibility and acceptability of a centralized, simulation-based training-programme. Simulation is increasingly establishing its role in urological training, with two areas that are relevant to urologists: (i) technical skills and (ii) non-technical skills.

Materials And Methods: For this London Deanery supported pilot Simulation and Technology enhanced Learning Initiative (STeLI) project, we developed a structured multimodal simulation training programme. The programme incorporated: (i) technical skills training using virtual-reality simulators (Uro-mentor and Perc-mentor [Symbionix, Cleveland, OH, USA], Procedicus MIST-Nephrectomy [Mentice, Gothenburg, Sweden] and SEP Robotic simulator [Sim Surgery, Oslo, Norway]); bench-top models (synthetic models for cystocopy, transurethral resection of the prostate, transurethral resection of bladder tumour, ureteroscopy); and a European (Aalborg, Denmark) wet-lab training facility; as well as (ii) non-technical skills/crisis resource management (CRM), using SimMan (Laerdal Medical Ltd, Orpington, UK) to teach team-working, decision-making and communication skills. The feasibility, acceptability and construct validity of these training modules were assessed using validated questionnaires, as well as global and procedure/task-specific rating scales.

Results: In total 33, three specialist registrars of different grades and five urological nurses participated in the present study. Construct-validity between junior and senior trainees was significant. Of the participants, 90% rated the training models as being realistic and easy to use. In total 95% of the participants recommended the use of simulation during surgical training, 95% approved the format of the teaching by the faculty and 90% rated the sessions as well organized. A significant number of trainees (60%) would like to have easy access to a simulation facility to allow more practice and enhancement of their skills.

Conclusions: A centralized simulation programme that provides training in both technical and non-technical skills is feasible. It is expected to improve the performance of future surgeons in a simulated environment and thus improve patient safety.
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http://dx.doi.org/10.1111/j.1464-410X.2012.11204.xDOI Listing
March 2013

Simulation training for hyperacute stroke unit nurses.

Br J Nurs 2011 Nov 24-Dec 7;20(21):1352-6

Stroke Unit, Department of Ageing & Health, St Thomas' Hospital, London, UK.

National clinical guidelines have emphasized the need to identify acute stroke as a clinical priority for early assessment and treatment of patients on hyperacute stroke units. Nurses working on hyperacute stroke units require stroke specialist training and development of competencies in dealing with neurological emergencies and working in multidisciplinary teams. Educational theory suggests that experiential learning with colleagues in real-life settings may provide transferable results to the workplace with improved performance. Simulation training has been shown to deliver situational training without compromising patient safety and has been shown to improve both technical and non-technical skills (McGaghie et al, 2010). This article describes the role that simulation training may play for nurses working on hyperacute stroke units explaining the modalities available and the educational potential. The article also outlines the development of a pilot course involving directly relevant clinical scenarios for hyperacute stroke unit patient care and assesses the benefits of simulation training for hyperacute stroke unit nurses, in terms of clinical performance and non-clinical abilities including leadership and communication.
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http://dx.doi.org/10.12968/bjon.2011.20.21.1352DOI Listing
February 2012

Tail-assisted pitch control in lizards, robots and dinosaurs.

Nature 2012 Jan 4;481(7380):181-4. Epub 2012 Jan 4.

Center for Interdisciplinary Bio-Inspiration in Education and Research, University of California, Berkeley, California 94720-3140, USA.

In 1969, a palaeontologist proposed that theropod dinosaurs used their tails as dynamic stabilizers during rapid or irregular movements, contributing to their depiction as active and agile predators. Since then the inertia of swinging appendages has been implicated in stabilizing human walking, aiding acrobatic manoeuvres by primates and rodents, and enabling cats to balance on branches. Recent studies on geckos suggest that active tail stabilization occurs during climbing, righting and gliding. By contrast, studies on the effect of lizard tail loss show evidence of a decrease, an increase or no change in performance. Application of a control-theoretic framework could advance our general understanding of inertial appendage use in locomotion. Here we report that lizards control the swing of their tails in a measured manner to redirect angular momentum from their bodies to their tails, stabilizing body attitude in the sagittal plane. We video-recorded Red-Headed Agama lizards (Agama agama) leaping towards a vertical surface by first vaulting onto an obstacle with variable traction to induce a range of perturbations in body angular momentum. To examine a known controlled tail response, we built a lizard-sized robot with an active tail that used sensory feedback to stabilize pitch as it drove off a ramp. Our dynamics model revealed that a body swinging its tail experienced less rotation than a body with a rigid tail, a passively compliant tail or no tail. To compare a range of tails, we calculated tail effectiveness as the amount of tailless body rotation a tail could stabilize. A model Velociraptor mongoliensis supported the initial tail stabilization hypothesis, showing as it did a greater tail effectiveness than the Agama lizards. Leaping lizards show that inertial control of body attitude can advance our understanding of appendage evolution and provide biological inspiration for the next generation of manoeuvrable search-and-rescue robots.
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http://dx.doi.org/10.1038/nature10710DOI Listing
January 2012

Gliding saves time but not energy in Malayan colugos.

J Exp Biol 2011 Aug;214(Pt 16):2690-6

Department of Integrative Biology, University of California, Berkeley, 3060 Valley Life Sciences Building, Berkeley, CA 94720-3140, USA.

Gliding is thought to be an economical form of locomotion. However, few data on the climbing and gliding of free-ranging gliding mammals are available. This study employed an animal-borne three-dimensional acceleration data-logging system to collect continuous data on the climbing and gliding of free-ranging Malayan colugos, Galeopterus variegatus. We combined these movement data with empirical estimates of the metabolic costs to move horizontally or vertically to test this long-standing hypothesis by determining whether the metabolic cost to climb to sufficient height to glide a given distance was less than the cost to move an equivalent distance horizontally through the canopy. On average, colugos climb a short distance to initiate glides. However, due to the high energetic cost of climbing, gliding is more energetically costly to move a given horizontal distance than would be predicted for an animal travelling the same distance through the canopy. Furthermore, because colugos spend a small fraction of their time engaged in locomotor activity, the high costs have little effect on their overall energy budget. As a result, the energetic economy hypothesis for the origins of gliding is not supported. It is likely that other ecologically relevant factors have played a greater role in the origins of gliding in colugos and other mammals.
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http://dx.doi.org/10.1242/jeb.052993DOI Listing
August 2011

Shifts in a single muscle's control potential of body dynamics are determined by mechanical feedback.

Philos Trans R Soc Lond B Biol Sci 2011 May;366(1570):1606-20

Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.

Muscles are multi-functional structures that interface neural and mechanical systems. Muscle work depends on a large multi-dimensional space of stimulus (neural) and strain (mechanical) parameters. In our companion paper, we rewrote activation to individual muscles in intact, behaving cockroaches (Blaberus discoidalis L.), revealing a specific muscle's potential to control body dynamics in different behaviours. Here, we use those results to provide the biologically relevant parameters for in situ work measurements. We test four hypotheses about how muscle function changes to provide mechanisms for the observed control responses. Under isometric conditions, a graded increase in muscle stress underlies its linear actuation during standing behaviours. Despite typically absorbing energy, this muscle can recruit two separate periods of positive work when controlling running. This functional change arises from mechanical feedback filtering a linear increase in neural activation into nonlinear work output. Changing activation phase again led to positive work recruitment, but at different times, consistent with the muscle's ability to also produce a turn. Changes in muscle work required considering the natural sequence of strides and separating swing and stance contributions of work. Both in vivo control potentials and in situ work loops were necessary to discover the neuromechanical coupling enabling control.
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http://dx.doi.org/10.1098/rstb.2010.0368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3130456PMC
May 2011

Dietary circumvention of acorn tannins by blue jays : Implications for oak demography.

Oecologia 1993 May;94(2):159-164

Department of Horticulture, Forestry, Landscape and Parks, South Dakota State University, 57007, Brookings, SD, USA.

Blue jays consume large quantities of acorns to fuel energy-demanding caching flights in the fall. Yet blue jays possess no known physiological adaptation to counter the negative effects of a high tannin diet on protein digestion. Dietary experiments were conducted to determine if blue jays could subsist on an acorn-only diet, and if they could not, to determine whether supplements of acorn weevil larvae (Curculio), present inside acorns, enabled them to maintain their mass. Comparative tannin assays also were conducted on Lepidobalanus (low tannin; white oak) and Erythrobalanus (high tannin; pin oak) acorns using radial diffusion assay. Captive jays consumed considerable acorn material, yet were unable to maintain mass on ad lib. acorn-only diets or on an acorn +1.5 g larvae/day supplement. There were no significant differences in mass loss between high and low tannin diets. In contrast, blue jays were able to stabilize mass on a diet of acorns +5.0 g larvae supplement/day. These results suggest that acorn weevil larvae, or perhaps other insects, counteract the effects of acorn tannins in the jay diet allowing jays to subsist largely on acorns during the fall caching season. Oak demographic processes may be partly regulated by a tri-trophic relationship among plant, insect and bird. Acorn weevil larvae, considered damaging to oak populations, may actually facilitate oak recruitment and population vagility in the long-term.
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http://dx.doi.org/10.1007/BF00341312DOI Listing
May 1993
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