Finite-element modelling of mechanobiological factors influencing sesamoid tissue morphology in the patellar tendon of an ostrich

The appearance and shape of sesamoid bones within a tendon or ligament wrapping around a joint are understood to be influenced by both genetic and epigenetic factors. Ostriches (Struthio camelus) possess two sesamoid patellae (kneecaps), one of which (the distal patella) is unique to their lineage, making them a good model for investigating sesamoid tissue development and evolution. Here we used finite-element modelling to test the hypothesis that specific mechanical cues in the ostrich patellar tendon favour the formation of multiple patellae. Using three-dimensional models that allow application of loading conditions in which all muscles, or only distal or only proximal muscles to be activated, we found that there were multiple regions within the tendon where transformation from soft tissue to fibrocartilage was favourable and therefore a potential for multiple patellae based solely upon mechanical stimuli. While more studies are needed to better understand universal mechanobiological principles as well as full developmental processes, our findings suggest that a tissue differentiation algorithm using shear strain and compressive strain as inputs may be a roughly effective predictor of the tissue differentiation required for sesamoid development

Enhancing farming system water productivity through alternative land use and improved water management of rainfed agriculture in Vertisol areas

Waterlogged Vertisols are amongst the high potential soils where management interventions could result in positive impacts. This study utilized soil, climate and crop and livestock productivity data and models to demonstrate intensification strategies which increase crop–livestock system productivity and to understand the effects of alternative land use and water management options on water productivity in the Vertisols areas. The areas have been classified into three slope classes including areas where artificial drainage is not feasible, where Broad Bed and Furrows (BBF) can be used to drain the excess water and naturally drained areas, represented by areas with 0–2%, 2–5% and over 5% slope steepness, respectively. Early planting of wheat (Triticum spp) using BBF on drainable areas and rice (Oryza sativa) or grasspea (Lathyrus sativus) on the flat areas were compared with the traditional practices. Yield and biomass data were obtained from research stations in the area whilst the effective rainfall and crop water requirement were estimated using CROPWAT Model. The feed value of the native grass and crop straw was estimated based on previous works. With respect to effective rainfall, the water productivity increase due to BBF over the control ranged from 5 to 200%, with an average increase of 57%. Despite higher water consumption of the rice, feeding its residues to livestock enhanced the overall economic water productivity of the system over the natural grazing or grasspea cultivation. Consequently, use of BBF enables growing high value or food crops of choice that may be sensitive to waterlogging whilst tolerant crops can be grown on flat lands allowing utilization of the full growing period. Coupled with livestock integration into the system, the alternatives can enhance food production and resource use efficiency from these ‘marginal’ areas

Three-dimensional anatomy of the ostrich (Struthio camelus) knee joint

The three-dimensional anatomy of the ostrich (Struthio camelus) knee (femorotibial, femorofibular, and femoropatellar) joint has scarcely been studied, and could elucidate certain mechanobiological properties of sesamoid bones. The adult ostrich is unique in that it has double patellae, while another similar ratite bird, the emu, has none. Understanding why these patellae form and what purpose they may serve is dually important for future studies on ratites as well as for understanding the mechanobiological characteristics of sesamoid bone development. For this purpose, we present a three-dimensional anatomical study of the ostrich knee joint, detailing osteology, ligaments and menisci, and myology. We have identified seven muscles which connect to the two patellae and compare our findings to past descriptions. These descriptions can be used to further study the biomechanical loading and implications of the double patella in the ostrich

Patterns of Celerity in British Columbia’s Provincial Courts

Presentation at the Western Society of Criminology Conference, 2016. Vancouver, BC

Speed reading courses and their effect on reading authentic texts: A preliminary investigation

Fluent reading is essential for successful comprehension. One dimension of reading fluency is reading rate, or reading speed. Because of the importance of reading fluency, fluency development activities should be incorporated into classroom practice. One activity that meets the fluency development conditions proposed by Nation (2007) is speed reading. An important question is whether reading speed gains measured in words per minute on controlled speed reading texts transfer to other types of texts. This paper reports on a preliminary, small-scale investigation of this question. The findings suggest that a speed reading course may contribute to faster reading speeds on other types of texts, but there remains a need for further experimental research into the impact of speed reading courses

Structure, ontogeny and evolution of the patellar tendon in emus (Dromaius novaehollandiae) and other palaeognath birds

The patella (kneecap) exhibits multiple evolutionary origins in birds, mammals, and lizards, and is thought to increase the mechanical advantage of the knee extensor muscles. Despite appreciable interest in the specialized anatomy and locomotion of palaeognathous birds (ratites and relatives), the structure, ontogeny and evolution of the patella in these species remains poorly characterized. Within Palaeognathae, the patella has been reported to be either present, absent, or fused with other bones, but it is unclear how much of this variation is real, erroneous or ontogenetic. Clarification of the patella’s form in palaeognaths would provide insight into the early evolution of the patella in birds, in addition to the specialized locomotion of these species. Findings would also provide new character data of use in resolving the controversial evolutionary relationships of palaeognaths. In this study, we examined the gross and histological anatomy of the emu patellar tendon across several age groups from five weeks to 18 months. We combined these results with our observations and those of others regarding the patella in palaeognaths and their outgroups (both extant and extinct), to reconstruct the evolution of the patella in birds. We found no evidence of an ossified patella in emus, but noted its tendon to have a highly unusual morphology comprising large volumes of adipose tissue contained within a collagenous meshwork. The emu patellar tendon also included increasing amounts of a cartilage-like tissue throughout ontogeny. We speculate that the unusual morphology of the patellar tendon in emus results from assimilation of a peri-articular fat pad, and metaplastic formation of cartilage, both potentially as adaptations to increasing tendon load. We corroborate previous observations of a ‘double patella’ in ostriches, but in contrast to some assertions, we find independent (i.e., unfused) ossified patellae in kiwis and tinamous. Our reconstructions suggest a single evolutionary origin of the patella in birds and that the ancestral patella is likely to have been a composite structure comprising a small ossified portion, lost by some species (e.g., emus, moa) but expanded in others (e.g., ostriches)