Musculoskeletal modelling of an ostrich (Struthio camelus) pelvic limb: influence of limb orientation on muscular capacity during locomotion

We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus) to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles) that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g., weighting of muscle force–length or force–velocity properties in selecting postures). This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model’s results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action) that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our results illustrate some cautionary principles. Importantly, tendon-travel empirical measurements of muscle moment arms must be carefully designed to preserve 3D muscle geometry lest their accuracy suffer relative to that of anatomically realistic models. The dearth of accurate experimental measurements of 3D moment arms of muscles in birds leaves uncertainty regarding the relative accuracy of different modelling or experimental datasets such as in ostriches. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in ostriches for the first time, emphasizing that avian limb mechanics are highly three-dimensional and complex, and how no muscles act purely in the sagittal plane. A comparative synthesis of experiments and models such as ours could provide powerful synthesis into how anatomy, mechanics and control interact during locomotion and how these interactions evolve. Such a framework could remove obstacles impeding the analysis of muscle function in extinct taxa

O etanol no jornalismo impresso brasileiro: entre a crise e o desenvolvimento

Análise da cobertura impressa do etanol durante os primeiros quinze dias do mês de abril de 2008, considerando os jornais especializados e também os não especializados na área econômica. A metodologia aplicada buscou observar a freqüência com que assuntos capazes de acelerar ou atrasar o desenvolvimento deste produto ganhavam visibilidade no jornal. E também identificar e qualificar as fontes mais recorrentes. A cobertura deste produto do segmento de energia atualizou no período um embate histórico entre dois discursos distintos: de um lado, o da crise sócio-ambiental, representado por organismos multilaterais como a FAO e o Banco Mundial, que destacaram as conseqüências sociais da elevação nos preços dos alimentos; de outro, o discurso do desenvolvimento econômico defendido por autoridades governamentais brasileiras e parte do setor privado deste país. Sem a pretensão de obter respostas definitivas, buscou-se realizar um exercício metodológico que sirva como subsídio para a construção de instrumentos de monitoramento no longo prazo da cobertura deste setor estratégico para fins econômicos, e decisivo para relações sociais e para com o meio ambiente

Computer Assisted Navigation in Knee Arthroplasty

Computer assisted surgery (CAS) was used to improve the positioning of implants during total knee arthroplasty (TKA). Most studies have reported that computer assisted navigation reduced the outliers of alignment and component malpositioning. However, additional sophisticated studies are necessary to determine if the improvement of alignment will improve long-term clinical results and increase the survival rate of the implant. Knowledge of CAS-TKA technology and understanding the advantages and limitations of navigation are crucial to the successful application of the CAS technique in TKA. In this article, we review the components of navigation, classification of the system, surgical method, potential error, clinical results, advantages, and disadvantages

Non-physician anaesthesia providers’ perspectives on task sharing practices in Zambia and Somaliland: a qualitative study

Introduction: The 68th World Health Assembly, in 2015, called for surgical and anaesthesia services strengthening. Acknowledging the healthcare staff shortages, they referred to task sharing, among others, as a more effective use of the healthcare workforce. While task sharing has been increasingly proposed as an important strategy to increase the reach and safety of anaesthesia as well as a means of supporting the workforce in low-resource settings, most data on task sharing relate to non-anaesthetic healthcare contexts. The aim of this study was to understand anaesthetic task sharing as currently experienced and/or envisaged by non-physician anaesthesia providers in Zambia and Somaliland. Methods: An exploratory qualitative research methodology was used. Participants were recruited initially via contacts of the research team, then through snowballing using a purposive sampling strategy. There were 13 participants: 7 from Somaliland and 6 from Zambia. Semistructured interviews took place synchronously, then were recorded, anonymised, transcribed and analysed thematically. Triangulation and respondents’ validation were used to maximise data validity. Results: Four major themes were identified in relation to task sharing practices: (1) participants recognised variable components of task sharing in their practice; (2) access to task sharing depends both on sources and resources; (3) implicit barriers may inhibit task sharing practices; (4) there is an appetite among participants for amelioration of current task sharing practices. Conclusions: Empowering task sharing practices can be achieved only by understanding how these practices work, by identifying gaps and areas of improvement, and by addressing them. The findings from this exploratory study could help the global community understand how anaesthetic task sharing in low-resource settings works and inspire further research on the field. This could inform future modelling of workforce planning strategies in low-resource settings to maximise the effectiveness and professional well-being of the workforce

Longitudinal Shapes of the Tibia and Femur are Unrelated and Variable

In general practice, short films of the knee are used to assess component position and define the entry point for intramedullary femoral alignment in TKAs; however, whether it is justified to use the short film commonly used in research settings and everyday practice as a substitute for the whole leg view is controversial and needs clarification. In 138 long leg CT scanograms we measured the angle formed by the anatomic axis of the proximal fourth of the tibia and the mechanical axis of the tibia, the angle formed by the anatomic axis of the distal fourth of the femur and the mechanical axis of the femur, the “bow” of the tibia (as reflected by the offset of the anatomic axis from the center of the talus), and the “bow” of the femur (as reflected by the offset of the anatomic axis from the center of the femoral head). Because the angle formed by these axes and the bow of the tibia and femur have wide variability in females and males, a short film of the knee should not be used in place of the whole leg view when accurate assessment of component position and limb alignment is essential. A previous study of normal limbs found that only 2% of subjects have a neutral hip-knee-ankle axis, which can be explained by the wide variability of the bow in the tibia and femur and the lack of correlation between the bow of the tibia and femur in a given limb as shown in the current study

Seasonal Influenza A (H1N1) Infection in Early Pregnancy and Second Trimester Fetal Demise

A second trimester fetal demise followed influenza-like illness in early pregnancy. Influenza A virus (H1N1) was identified in maternal and fetal tissue, confirming transplacental passage. These findings suggested a causal relationship between early exposure and fetal demise. Management of future influenza outbreaks should include evaluation of products of conception associated with fetal loss

A collective autoethnography of coproduction in mental health research by academic researchers and young people in Brazil

Introduction Coproduction of mental health research and interventions involving researchers and young people is increasingly common. However, this model raises challenges, related, for instance, to communication, power and control. This paper narrates—from a collective first-person perspective—the lived experience of coproduction of a digital intervention by institutional researchers and young citizen researchers in Brazil. Method This study employed a collaborative autoethnographic methodology, utilising autobiographical data such as meeting recordings, individual notes and collective guided reflections on the coproduction process. Our analysis focused on challenges and solutions that arose during the process. Results Throughout the project, we created formal and informal mechanisms for accountability, transparency and fair inclusion of multiple voices. We engaged in mutual capacity-building, invested in building interpersonal knowledge, and implemented practices to reduce overload and promote equitable participation. Through ongoing reflection and readjustment in response to challenges, we progressively embraced more democratic and egalitarian values. The collective care invested in the process fostered synergy, trust, and intergroup friendship. Conclusion Our experience points to the value of creating a space for multiple research identities: the citizen young person and the institutional researcher, both of whom critically reflect on their roles in the research process. Our focus on coproduced care calls into question participation metaphors that represent the process via a single axis—young people—who linearly progress from minimal participation to full autonomy. Instead, our analysis highlights the importance of a social and caring bond that supports the radical co-production of innovative health solutions in contexts of vulnerability