Maximizing Learning Opportunities Through Activity Modification

While the challenges of including all students in physical education are real, there is one overriding consideration: How successful is each child as a result of the teaching approach adopted? Considering the importance of accommodating all students, it is essential that practitioners explore new ways of teaching, discover a range of strategies for including students with diverse abilities, and continually rethink and revise lessons and activities. More than asking which students to include and how to accommodate only these students, practitioners should be asking how they can modify activities for all students to be successful. More than likely, the answer to this question is also complex. Yet, it is not easily discarded when the alternative is a class in which only the skilled feel good about their involvement and achieve desired outcomes, and those less skilled are at risk for ceasing physical activity participation. It also ignores those most skilled who stop participating due to a lack of challenging activities and subsequent boredom. Teaching approaches, inclusive of all, are critical to the success and commitment of all students. While good inclusionary practice takes time and support, the benefits are far reaching

Characterization of gravity current formation for the use in detonation refraction experiments

Detonation propagation through an interface is being studied at Caltech. In these experiments, the interface shape is determined by the gravity currents. This report presents an experimental study of the formation and the development of these gravity currents by an analog system in a water channel using water and salt water to simulate the density differences in detonation experiments. The major parameters such as the Reynolds number and the density difference were matched in both experiments to be able to compare the gravity current in the water channel and the gravity current in the Galcit detonation tube. In the present study, the gravity current was generated by the removal of a plate, and was visualized by adding food dye. The results confirm previous studies; Keulegan demonstrated in 1957 that the velocity of the gravity current is a function of the square root of the density difference. The interface is affect by the retracting of the plate which creates the wake effects. The Kelvin-Helmholtz instabilities on the upstream side of the gravity current create the visualized mixing zones. Finally, this study revealed how the gravity current interface into the Galcit detonation tube should develop and where the mixing zones should occur

Expansion of pinched hypersurfaces of the Euclidean and hyperbolic space by high powers of curvature

We prove convergence results for expanding curvature flows in the Euclidean and hyperbolic space. The flow speeds have the form $F^{-p}$, where $p>1$ and $F$ is a positive, strictly monotone and 1-homogeneous curvature function. In particular this class includes the mean curvature $F=H$. We prove that a certain initial pinching condition is preserved and the properly rescaled hypersurfaces converge smoothly to the unit sphere. We show that an example due to Andrews-McCoy-Zheng can be used to construct strictly convex initial hypersurfaces, for which the inverse mean curvature flow to the power $p>1$ loses convexity, justifying the necessity to impose a certain pinching condition on the initial hypersurface.Comment: 18 pages. We included an example for the loss of convexity and pinching. In the third version we dropped the concavity assumption on F. Comments are welcom

Magpie: towards a semantic web browser

Web browsing involves two tasks: finding the right web page and then making sense of its content. So far, research has focused on supporting the task of finding web resources through ‘standard’ information retrieval mechanisms, or semantics-enhanced search. Much less attention has been paid to the second problem. In this paper we describe Magpie, a tool which supports the interpretation of web pages. Magpie offers complementary knowledge sources, which a reader can call upon to quickly gain access to any background knowledge relevant to a web resource. Magpie automatically associates an ontologybased semantic layer to web resources, allowing relevant services to be invoked within a standard web browser. Hence, Magpie may be seen as a step towards a semantic web browser. The functionality of Magpie is illustrated using examples of how it has been integrated with our lab’s web resources

Connecting Through Summer Camp: Youth with Visual Impairments Find a Sense of Community

The social meaning of a one-week residential summer sports camp to young people with visual impairments is described. The experiences of 13 youths (7 females and 6 males) with visual impairments (3 B1, 1 B2, and 9 B3) between 9 and 15 years of age were gathered using the phenomenological methods of focus groups, conversational interviews, and field notes. The thematic analysis revealed three themes: connected, reaching out, and resisting and acquiescing. Experiences of group membership and shared emotional connection to others with visual impairments surfaced in a supportive sport context although resistance to others\u27 assumptions of ability was evident. The theory of psychological sense of community (McMillan & Chivas, 1986) provided the conceptual framework for interpreting the findings

Validation of Nike Fuel Band Step Counter in Children with Visual Impairments

Please view abstract in the attached PDF file

Motivational Effects of Physical Activity Monitoring Bands and Talking Pedometers on Children with Visual Impairments

Please view abstract in the attached PDF file

Electron surface layer at the interface of a plasma and a dielectric wall

We study the potential and the charge distribution across the interface of a plasma and a dielectric wall. For this purpose, the charge bound to the wall is modelled as a quasi-stationary electron surface layer which satisfies Poisson's equation and minimizes the grand canonical potential of the wall-thermalized excess electrons constituting the wall charge. Based on an effective model for a graded interface taking into account the image potential and the offset of the conduction band to the potential just outside the dielectric, we specifically calculate the potential and the electron distribution for magnesium oxide, silicon dioxide and sapphire surfaces in contact with a helium discharge. Depending on the electron affinity of the surface, we find two vastly different behaviors. For negative electron affinity, electrons do not penetrate into the wall and an external surface charge is formed in the image potential, while for positive electron affinity, electrons penetrate into the wall and a space charge layer develops in the interior of the dielectric. We also investigate how the electron surface layer merges with the bulk of the dielectric.Comment: 15 pages, 9 figures, accepted versio

Partial Schauder estimates for second-order elliptic and parabolic equations

We establish Schauder estimates for both divergence and non-divergence form second-order elliptic and parabolic equations involving H\"older semi-norms not with respect to all, but only with respect to some of the independent variables.Comment: CVPDE, accepted (2010)

Rotational symmetry of self-similar solutions to the Ricci flow

Let (M,g) be a three-dimensional steady gradient Ricci soliton which is non-flat and \kappa-noncollapsed. We prove that (M,g) is isometric to the Bryant soliton up to scaling. This solves a problem mentioned in Perelman's first paper.Comment: Final version, to appear in Invent. Mat