Geographic range size and evolutionary age in birds

Together with patterns of speciation and extinction, post-speciation transformations in the range sizes of individual species determine the form of contemporary species-range-size distributions. However, the methodological problems associated with tracking the dynamics of a species' range size over evolutionary time have precluded direct study of such range-size transformations, although indirect evidence has led to several models being proposed describing the form that they might take. Here, we use independently derived molecular data to estimate ages of species in six monophyletic groups of birds, and examine the relationship between species age and global geographic range size. We present strong evidence that avian range sizes are not static over evolutionary time. In addition, it seems that, with the regular exception of certain taxa (for example island endemics and some threatened species), range-size transformations are non-random in birds. In general, range sizes appear to expand relatively rapidly post speciation; subsequently, and perhaps more gradually, they then decline as species age. We discuss these results with reference to the various models of range-size dynamics that have been proposed

Diffusive electron acceleration at SNR shock fronts and the observed SNR radio spectral indices

The radio synchrotron emission from relativistic electrons in shell supernova remnants (SNRs) provides a unique opportunity to probe the energy distribution of energetic electrons at their acceleration site (SNR shock fronts). This information provides insight into the acceleration mechanism(s). The implications of these observations for the diffusive (first-order Fermi) acceleration of electrons at the SNR shock fronts are discussed

The integration of tgfu into the secondary school physical education curriculum – how successful has it been?.

In 2005, a new Personal Development, Health and Physical Education (PDHPE) Years 7–10 Syllabus (Board of Studies, 2003) was implemented in NSW (Australia) secondary schools. One area that underwent major changes within the syllabus was that of the teaching of games, with the move towards a TGfU framework. Forty PDHPE teachers were surveyed with questionnaires and focus group interviews to determine their knowledge and understanding of TGfU and the extent to which they have incorporated TGfU into their teaching of games. Pre-service teachers’ observations of Physical Education classes were also used to determine the extent that TGfU was being implemented. Fifty-five percent of PDHPE teachers surveyed had poor knowledge and understanding of TGfU, with 32% unaware that the principles of TGfU were written into the PDHPE syllabus. Forty-five percent of teachers reported that they had incorporated TGfU to some extent into their teaching of games, however only 22% of pre-service teachers surveyed indicated that they had observed classes that incorporated TGfU principles. Continuing teacher training and development is required to support teachers in developing an understanding and skills necessary to utilise a TGfU approach that underpins the teaching of games within the new NSW Years 7-10 PDHPE syllabus

Progenitor cells in auricular cartilage demonstrate cartilage-forming capacity in 3D hydrogel culture

Paramount for the generation of auricular structures of clinically-relevant size is the acquisition of a large number of cells maintaining an elastic cartilage phenotype, which is the key in producing a tissue capable of withstanding forces subjected to the auricle. Current regenerative medicine strategies utilize chondrocytes from various locations or mesenchymal stromal cells (MSCs). However, the quality of neo-tissues resulting from these cell types is inadequate due to inefficient chondrogenic differentiation and endochondral ossification, respectively. Recently, a subpopulation of stem/progenitor cells has been identified within the auricular cartilage tissue, with similarities to MSCs in terms of proliferative capacity and cell surface biomarkers, but their potential for tissue engineering has not yet been explored. This study compared the in vitro cartilage-forming ability of equine auricular cartilage progenitor cells (AuCPCs), bone marrow-derived MSCs and auricular chondrocytes in gelatin methacryloyl (gelMA)-based hydrogels over a period of 56 d, by assessing their ability to undergo chondrogenic differentiation. Neocartilage formation was assessed through gene expression profiling, compression testing, biochemical composition and histology. Similar to MSCs and chondrocytes, AuCPCs displayed a marked ability to generate cartilaginous matrix, although, under the applied culture conditions, MSCs outperformed both cartilage-derived cell types in terms of matrix production and mechanical properties. AuCPCs demonstrated upregulated mRNA expression of elastin, low expression of collagen type X and similar levels of proteoglycan production and mechanical properties as compared to chondrocytes. These results underscored the AuCPCs' tissue-specific differentiation potential, making them an interesting cell source for the next generation of elastic cartilage tissue-engineered constructs

Discovery of seven T Tauri stars and a brown dwarf candidate in the nearby TW Hydrae Association

We report the discovery of five T Tauri star systems, two of which are resolved binaries, in the vicinity of the nearest known region of recent star formation, the TW Hydrae Association. The newly discovered systems display the same signatures of youth (namely high X-ray flux, large Li abundance and strong chromospheric activity) and the same proper motion as the original five members. These similarities firmly establish the group as a bona fide T Tauri association, unique in its proximity to Earth and its complete isolation from any known molecular clouds. At an age of ~10 Myr and a distance of ~50 pc, the association members are excellent candidates for future studies of circumstellar disk dissipation and the formation of brown dwarfs and planets. Indeed, as an example, our speckle imaging revealed a faint, very likely companion 2" north of CoD-33 7795 (TWA 5). Its color and brightness suggest a spectral type ~M8.5 which, at an age of ~10^7 years, implies a mass ~20 M(Jupiter).Comment: 6 pages, 4 figures and 1 table. AAS LaTeX aas2pp4.sty. To be published in Ap

Promoting physical activity through teaching games for understanding in undergraduate teacher education

Physical education teachers play a significant role in influencing the likelihood that their students will engage in lifelong physical activity. However, with declining physical activity levels, particularly amongst young people, and the increased prevalence of obese and overweight children and adolescents, promoting lifelong physical activity is one of the many challenges currently facing physical education teachers. Teachers are required to engage students in quality learning opportunities to develop prescribed learning outcomes and skills, and make the experience enjoyable to enthuse young people to be physically active. This study examines whether teaching games for understanding (TGfU) and technique based pedagogy models in touch football lessons influenced participant physical activity and enjoyment levels