Professional development learning environments (PDLEs) embedded in a collaborative online learning environment (COLE): Moving towards a new conception of online professional learning

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Teaching, and education in general, remain firmly rooted in the practices of the past and continue to resist the implementation of strategies and theories arising from educational research. Consequently, significant reforms have been slow to take hold in educational systems around the world. Much of the reluctance can be attributed to a widely-held misconception of the nature of learning. This project attempts to address this misconception through the development of Professional Development Learning Environments (PDLEs are a series of learning tasks and a video-based case study) embedded in an online learning environment that requires the collaboration of users to solve problems. To use a Problem-Based-Learning (PBL) approach in an online context requires a major paradigm shift as well as using tools that were not designed specifically for such a student-driven, process-centred pedagogical paradigm. This becomes a problem when online resources and systems are used for supporting in-service teacher in their pursuit of furthering their education. Although the current theories of learning and teaching may present the philosophical content of such courses, the online strategies used often conflict with the theory. To study the formal implementation of PBL as a social-constructivist pedagogical approach, into an online learning environment to provide the tools for e-learning that would be closer in design to the current thinking on the very nature of learning, the PDLEs were modified to become small reusable video clips with a structure designed to facilitate PBL and focus learners’ attention on higher order thinking skills rather than specifically on content. These modified PDLEs are referred to as Problem-Based Learning Objects (PBLOs). The PBLOs were embedded into a prototype of a Collaborative Online Learning Environment (COLE) which was developed simultaneously. The entire system was pilot tested with small groups. Preliminary results show that although many technical difficulties remain to be solved, using the environment does show evidence of some effect on beliefs about personal theories of learning, causing shifts from technical issues to those surrounding processes of learning. Our preliminary research has called attention to the potential ability of PBLO/COLE to disrupt conventional, transmission-based conceptions of online learning as content delivery. At the same time, however, our preliminary work has also indicated that learners who are not used to the collaborative opportunities provided within PBLO/COLE may still hold traditional orientations to teaching and learning as a “gold standard” to which all other options are compared. A purposeful direction for our future research will entail working with learners in PBLO/COLE over a sustained period so that they may engage in an online experience grounded in principles of socio-constructivism

The origin of the E+ transition in GaAsN alloys

Optical properties of GaAsN system with nitrogen concentrations in the range of 0.9-3.7% are studied by full-potential LAPW method in a supercell approach. The E+ transition is identified by calculating the imaginary part of the dielectric function. The evolution of the energy of this transition with nitrogen concentration is studied and the origin of this transition is identified by analyzing the contributions to the dielectric function from different band combinations. The L_1c-derived states are shown to play an important role in the formation of the E+ transition, which was also suggested by recent experiments. At the same time the nitrogen-induced modification of the first conduction band of the host compound are also found to contribute significantly to the E+ transition. Further, the study of several model supercells demonstrated the significant influence of the nitrogen potential on the optical properties of the GaAsN system.Comment: 5 pages, 3 figure

Multi-scale analysis of compressible viscous and rotating fluids

We study a singular limit for the compressible Navier-Stokes system when the Mach and Rossby numbers are proportional to certain powers of a small parameter \ep. If the Rossby number dominates the Mach number, the limit problem is represented by the 2-D incompressible Navier-Stokes system describing the horizontal motion of vertical averages of the velocity field. If they are of the same order then the limit problem turns out to be a linear, 2-D equation with a unique radially symmetric solution. The effect of the centrifugal force is taken into account

Stellar Populations in Compact Galaxy Groups: a Multi-Wavelength Study of HCGs 16, 22, and 42, their Star Clusters and Dwarf Galaxies

We present a multi-wavelength analysis of three compact galaxy groups, HCGs 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, HST, Spitzer) and ground-based (LCO, CTIO) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 'associates' (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (a) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (b) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.Comment: 29 pages, 13 figures. Accepted for publication in The Astrophysical Journa

Optical fiber laser ultrasound transmitter with electrospun composite for minimally invasive medical imaging

We report an optical fiber ultrasound transmitter with electrospun MWCNT-polymer composite, generating high-amplitude broadband ultrasound. They produced pressures in the range of conventional intravascular imaging transducers, and can be incorporated into catheters/needles for keyhole surgery

Global Solution to the Three-Dimensional Incompressible Flow of Liquid Crystals

The equations for the three-dimensional incompressible flow of liquid crystals are considered in a smooth bounded domain. The existence and uniqueness of the global strong solution with small initial data are established. It is also proved that when the strong solution exists, all the global weak solutions constructed in [16] must be equal to the unique strong solution

Patient-specific polyvinyl alcohol phantom fabrication with ultrasound and x-ray contrast for brain tumor surgery planning

Phantoms are essential tools for clinical training, surgical planning and the development of novel medical devices. However, it is challenging to create anatomically accurate head phantoms with realistic brain imaging properties because standard fabrication methods are not optimized to replicate any patient-specific anatomical detail and 3D printing materials are not optimized for imaging properties. In order to test and validate a novel navigation system for use during brain tumor surgery, an anatomically accurate phantom with realistic imaging and mechanical properties was required. Therefore, a phantom was developed using real patient data as input and 3D printing of molds to fabricate a patient-specific head phantom comprising the skull, brain and tumor with both ultrasound and X-ray contrast. The phantom also had mechanical properties that allowed the phantom tissue to be manipulated in a similar manner to how human brain tissue is handled during surgery. The phantom was successfully tested during a surgical simulation in a virtual operating room. The phantom fabrication method uses commercially available materials and is easy to reproduce. The 3D printing files can be readily shared, and the technique can be adapted to encompass many different types of tumor

Carbon content in amazonian oxisols after forest conversion to pasture.

O solo desempenha importante papel no ciclo do C, porém a substituição da floresta tropical por áreas cultivadas altera a dinâmica e o estoque desse elemento. Em uma frente pioneira de colonização no município de Itupiranga (PA), na Amazônia Oriental, foi desenvolvido este estudo com o objetivo de avaliar as consequências da substituição de floresta nativa por pastagens de Brachiaria brizantha no conteúdo de C de um Latossolo Amarelo distrófico. As amostras de solo foram coletadas em área de floresta nativa (FN), floresta secundária de 8?10 anos (FS), pastagens de 1?2 anos (P1-2), de 5?7 anos (P5?7) e de 10?12 anos (P10?12), nas camadas de 0?2, 2?5 e 5?10 cm, para avaliar os teores e o estoque de C e realizar um fracionamento granulométrico da matéria orgânica. Após o desmatamento, a densidade do solo aumentou até a profundidade de 5 cm, sendo esse aumento maior nas pastagens mais antigas. As maiores mudanças no conteúdo de C ocorreram na camada superior do solo, havendo aumento nesse conteúdo com o tempo de implantação das pastagens. Nas camadas de 2?5 e 5?10 cm, o conteúdo de C se mostrou estável entre os tipos de cobertura vegetal avaliados. As maiores concentrações de C foram encontradas na fração silte, mas os maiores conteúdos de C ocorreram na fração argila, independentemente do tipo de cobertura vegetal. Um aumento da quantidade de C associado à fração areia, na forma de resíduos orgânicos pouco decompostos, foi observado nas pastagens, confirmando a maior sensibilidade dessa fração às mudanças de uso do solo