Why do Large Animals Never Actuate Their Jumps with Latch-Mediated Springs? Because They can Jump Higher Without Them.

As animals get smaller, their ability to generate usable work from muscle contraction is decreased by the muscle's force-velocity properties, thereby reducing their effective jump height. Very small animals use a spring-actuated system, which prevents velocity effects from reducing available energy. Since force-velocity properties reduce the usable work in even larger animals, why don't larger animals use spring-actuated jumping systems as well? We will show that muscle length-tension properties limit spring-actuated systems to generating a maximum one-third of the possible work that a muscle could produce-greatly restricting the jumping height of spring-actuated jumpers. Thus a spring-actuated jumping animal has a jumping height that is one-third of the maximum possible jump height achievable were 100% of the possible muscle work available. Larger animals, which could theoretically use all of the available muscle energy, have a maximum jumping height that asymptotically approaches a value that is about three times higher than that of spring-actuated jumpers. Furthermore, a size related "crossover point" is evident for these two jumping mechanisms: animals smaller than this point can jump higher with a spring-actuated mechanism, while animals larger than this point can jump higher with a muscle-actuated mechanism. We demonstrate how this limit on energy storage is a consequence of the interaction between length-tension properties of muscles and spring stiffness. We indicate where this crossover point occurs based on modeling and then use jumping data from the literature to validate that larger jumping animals generate greater jump heights with muscle-actuated systems than spring-actuated systems

What Australian students say about transition to secondary school. Final report

Life Education Australia\u27s Being Healthy Being Active project involved the collection of student voice related to the concept of school transition and the move from primary to secondary school. Students from around Australia participated in 82 focus groups, or student forums, to discuss their own positive experiences, as well as perceived needs and challenges related to their move to secondary school. Section One of this report is a literature review and environmental scan on student transition from primary to secondary school. Section Two describes the methods used to design and administer the Student Forums. This includes a description of the target population and sampling methods as well as the details of the achieved sample: 82 forums with 444 students across 15 schools. Section Three outlines the findings of the Student Forums. Section Four offers conclusions and recommendations to inform the next stage of the project, designing a suite of resources and training for teachers aimed at assisting students with the transition from primary to secondary school

The Northern Tornadoes Project - Uncovering Canada’s True Tornado Climatology

Canada is a vast country with most of its population located along its southern border. Large areas are sparsely populated and/or heavily forested, and severe weather reports are rare when thunderstorms occur there. Thus, it has been difficult to accurately assess the true tornado climatology and risk. It is also important to establish a reliable baseline for tornado-related climate change studies. The Northern Tornadoes Project (NTP), led by Western University, is an ambitious multidisciplinary initiative aimed at detecting and documenting every tornado that occurs across Canada. A team of meteorologists and wind engineers collects research-quality data during each damage investigation, via thorough ground surveys and high-resolution satellite, aircraft and drone imaging. Crowdsourcing through social media is also key to tracking down events. In addition, NTP conducts research to improve our ability to detect and accurately assess tornadoes that affect forests, cropland and grassland. An open data website allows sharing of resulting data sets and analyses. Pilot investigations were carried out during the warm seasons of 2017 and 2018, with the scope expanding from the detection of any tornadoes in heavily forested regions of central Canada in 2017 to the detection of all EF1+ tornadoes in Ontario plus all significant events outside of Ontario in 2018. The 2019 season was the first full campaign, systemically collecting research-quality tornado data across the entire country. To date, the Project has found 89 tornadoes that otherwise would not have been identified, and increased the national tornado count in 2019 by 78%. © 2020 American Meteorological Societ

Epigenetic regulation of COL15A1 in smooth muscle cell replicative aging and atherosclerosis

Smooth muscle cell (SMC) proliferation is a hallmark of vascular injury and disease. Global hypomethylation occurs during SMC proliferation in culture and in vivo during neointimal formation. Regardless of the programmed or stochastic nature of hypomethylation, identifying these changes is important in understanding vascular disease, as maintenance of a cells' epigenetic profile is essential for maintaining cellular phenotype. Global hypomethylation of proliferating aortic SMCs and concomitant decrease of DNMT1 expression were identified in culture during passage. An epigenome screen identified regions of the genome that were hypomethylated during proliferation and a region containing Collagen, type XV, alpha 1 (COL15A1) was selected by ‘genomic convergence' for characterization. COL15A1 transcript and protein levels increased with passage-dependent decreases in DNA methylation and the transcript was sensitive to treatment with 5-Aza-2′-deoxycytidine, suggesting DNA methylation-mediated gene expression. Phenotypically, knockdown of COL15A1 increased SMC migration and decreased proliferation and Col15a1 expression was induced in an atherosclerotic lesion and localized to the atherosclerotic cap. A sequence variant in COL15A1 that is significantly associated with atherosclerosis (rs4142986, P = 0.017, OR = 1.434) was methylated and methylation of the risk allele correlated with decreased gene expression and increased atherosclerosis in human aorta. In summary, hypomethylation of COL15A1 occurs during SMC proliferation and the consequent increased gene expression may impact SMC phenotype and atherosclerosis formation. Hypomethylated genes, such as COL15A1, provide evidence for concomitant epigenetic regulation and genetic susceptibility, and define a class of causal targets that sit at the intersection of genetic and epigenetic predisposition in the etiology of complex diseas

Mortality associated with moderate and severe mitral regurgitation in 608 570 men and women undergoing echocardiography

Background Although the prognostic implications of severe mitral regurgitation (MR) are well recognised, they are less clear in moderate MR. We therefore explored the prognostic impact of both moderate and severe MR within the large National Echocardiography Database Australia cohort. Methods Echocardiography reports from 608 570 individuals were examined using natural language processing to identify MR severity and leaflet pathology. Atrial (aFMR) or ventricular (vFMR) functional MR was assessed in those without reported leaflet pathology. Using individual data linkage over median 1541 (IQR 820 to 2629) days, we examined the association between MR severity and all-cause (153 612/25.2% events) and cardiovascular-related mortality (47 840/7.9% events). Results There were 319 808 men and 288 762 women aged 62.1±18.5 years, of whom 456 989 (75.1%), 102 950 (16.9%), 38 504 (6.3%) and 10 127 (1.7%) individuals had no/trivial, mild, moderate and severe MR, respectively, reported on their last echo. Compared with those with no/trivial MR (26.5% had leaflet pathology, 19.2% died), leaflet pathology (51.8% and 78.9%, respectively) and actual 5-year all-cause mortality (54.6% and 67.5%, respectively) increased with MR severity. On an adjusted basis (age, sex and leaflet pathology), long-term mortality was 1.67-fold (95% CI 1.65 to 1.70) and 2.36-fold (95% CI 2.30 to 2.42) higher in moderate and severe MR cases (p<0.001) compared with no/trivial MR. The prognostic pattern for moderate and severe MR persisted for cardiovascular-related mortality and within prespecified subgroups (leaflet pathology, vFMR or aFMR, and age<65 years). Conclusions Within a large real-world clinical cohort, we confirm that conservatively managed severe MR is associated with a poor prognosis. We further reveal that moderate MR is associated with increased mortality, irrespective of underlying aetiology. Trial registration Australian New Zealand Clinical Trials Registry (ACTRN12617001387314

Influence of an ionic comonomer on polymerization-induced self-assembly of diblock copolymers in non-polar media

A series of poly(stearyl methacrylate)-poly(benzyl methacrylate) (PSMA-PBzMA) diblock copolymer nano-objects has been synthesized via reversible addition-fragmentation chain-transfer (RAFT) dispersion polymerization in n-dodecane at 20 wt%. This polymerization-induced self-assembly (PISA) formulation was modified by the incorporation of an anionic monomer, tetradodecylammonium 3-sulfopropyl methacrylate ([NDod 4] +[SPMA] -) into the oil-insoluble PBzMA block. According to the literature (M. J. Derry, et al., Chem. Sci., 2016, 7, 5078-5090), PSMA 18-PBzMA diblock copolymers only form spheres using this formulation for any core degree of polymerization. Unexpectedly, incorporating just a small fraction (<6 mol%) of [NDod 4] +[SPMA] - comonomer into the structure-directing block resulted in the formation of non-spherical diblock copolymer nano-objects, including pure worm-like and vesicular morphologies. However, only spherical micelles could be formed using a longer PSMA 34 stabilizer. These diblock copolymer nano-objects were characterized by transmission electron microscopy, small-angle X-ray scattering, and dynamic light scattering. The bulky nature of the ionic comonomer appears to make it possible to avoid the kinetically-trapped sphere morphology. This study reveals a new approach for tuning the morphology of diblock copolymer nano-objects in non-polar media

Why don't large animals exclusively use springs to jump? Because they can jump higher without them

As animals get smaller, their ability to generate usable work from muscle contraction is decreased by the muscle’s force-velocity properties, thereby reducing their effective jump height. Very small animals use a spring-actuated system, which prevents velocity effects from reducing available energy. Since force-velocity properties reduce the usable work in even larger animals, why don’t larger animals use spring-actuated jumping systems as well? We will show that muscle length-tension properties limit spring-actuated systems to generating a maximum 1/3 of the possible work that a muscle could produce – greatly restricting the jumping height of spring-actuated jumpers. Thus a spring-actuated jumping animal has a jumping height that is 1/3 of the maximum possible jump height achievable were 100% of the possible muscle work available. Larger animals, which could theoretically use all of the available muscle energy, have a maximum jumping height that asymptotically approaches a value that is about 3 times higher than that of spring-actuated jumpers. Furthermore, a size related ‘crossover point’ is evident for these two jumping mechanisms: animals smaller than this point can jump higher with a spring-actuated mechanism, while animals larger than this point can jump higher with a muscle-actuated mechanism. We demonstrate how this limit on energy storage is a consequence of the interaction between length-tension properties of muscles and spring stiffness. We indicate where this crossover point occurs based on modelling and then use jumping data from the literature to validate that larger jumping animals generate greater jump heights with muscle-actuated systems than spring-actuated systems

Coarsening Dynamics of Domains in Lipid Membranes

We investigate isothermal diffusion and growth of micron-scale liquid domains within membranes of free-floating giant unilamellar vesicles with diameters between 80 and 250 Am. Domains appear after a rapid temperature quench, when the membrane is cooled through a miscibility phase transition such that coexisting liquid phases form. In membranes quenched far from a miscibility critical point, circular domains nucleate and then progress within seconds to late stage coarsening in which domains grow via two mechanisms 1), collision and coalescence of liquid domains, and 2), Ostwald ripening. Both mechanisms are expected to yield the same growth exponent, alpha = 1/3, where domain radius grows as time(alpha). We measure alpha = 0.28 +/- 0.05, in excellent agreement. In membranes close to a miscibility critical point, the two liquid phases in the membrane are bicontinuous. A quench near the critical composition results in rapid changes in morphology of elongated domains. In this case, we measure alpha = 0.50 +/- 0.16, consistent with theory and simulation