Multicultural picture books: Windows and mirrors

Multicultural children’s picture books offer readers views into far away places that can be similar or very different from that of the reader. These picture books can be used to enhance the Social Studies curriculum by offering students new perspectives on other cultures. The researcher employed the five dimensions of global perspectives developed by Robert G. Hanvey (1976) and criteria from the Iowa Core Curriculum Social Studies Standards (grades 3-5), to determine the titles that best exemplified the criteria. Review of related literature included the topics of multicultural education, multicultural literature and reader-text-relationships. The project consists of an annotated bibliography of twenty multicultural picture books selected for purchase to incorporate into the Social Studies curriculum. The annotations include suggested thematic connections

Non-symmetric trapped surfaces in the Schwarzschild and Vaidya spacetimes

Marginally trapped surfaces (MTSs) are commonly used in numerical relativity to locate black holes. For dynamical black holes, it is not known generally if this procedure is sufficiently reliable. Even for Schwarzschild black holes, Wald and Iyer constructed foliations which come arbitrarily close to the singularity but do not contain any MTSs. In this paper, we review the Wald-Iyer construction, discuss some implications for numerical relativity, and generalize to the well known Vaidya spacetime describing spherically symmetric collapse of null dust. In the Vaidya spacetime, we numerically locate non-spherically symmetric trapped surfaces which extend outside the standard spherically symmetric trapping horizon. This shows that MTSs are common in this spacetime and that the event horizon is the most likely candidate for the boundary of the trapped region.Comment: 4 pages, 3 figures; v2: minor modifications; v3: clarified conclusion

Automatic correction of hand pointing in stereoscopic depth

In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (≤300 ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190 ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)

High accuracy binary black hole simulations with an extended wave zone

We present results from a new code for binary black hole evolutions using the moving-puncture approach, implementing finite differences in generalised coordinates, and allowing the spacetime to be covered with multiple communicating non-singular coordinate patches. Here we consider a regular Cartesian near zone, with adapted spherical grids covering the wave zone. The efficiencies resulting from the use of adapted coordinates allow us to maintain sufficient grid resolution to an artificial outer boundary location which is causally disconnected from the measurement. For the well-studied test-case of the inspiral of an equal-mass non-spinning binary (evolved for more than 8 orbits before merger), we determine the phase and amplitude to numerical accuracies better than 0.010% and 0.090% during inspiral, respectively, and 0.003% and 0.153% during merger. The waveforms, including the resolved higher harmonics, are convergent and can be consistently extrapolated to $r\to\infty$ throughout the simulation, including the merger and ringdown. Ringdown frequencies for these modes (to $(\ell,m)=(6,6)$) match perturbative calculations to within 0.01%, providing a strong confirmation that the remnant settles to a Kerr black hole with irreducible mass $M_{\rm irr} = 0.884355\pm20\times10^{-6}$ and spin $S_f/M_f^2 = 0.686923 \pm 10\times10^{-6}

Observing object lifting errors modulates cortico-spinal excitability and improves object lifting performance.

PublishedJournal ArticleObserving the actions of others has been shown to modulate cortico-spinal excitability and affect behaviour. However, the sensorimotor consequences of observing errors are not well understood. Here, participants watched actors lift identically weighted large and small cubes which typically elicit expectation-based fingertip force errors. One group of participants observed the standard overestimation and underestimation-style errors that characterise early lifts with these cubes (Error video--EV). Another group watched the same actors performing the well-adapted error-free lifts that characterise later, well-practiced lifts with these cubes (No error video--NEV). We then examined actual object lifting performance in the subjects who watched the EV and NEV. Despite having similar cognitive expectations and perceptions of heaviness, the group that watched novice lifters making errors themselves made fewer overestimation-style errors than those who watched the expert lifts. To determine how the observation of errors alters cortico-spinal excitability, we measured motor evoked potentials in separate group of participants while they passively observed these EV and NEV. Here, we noted a novel size-based modulation of cortico-spinal excitability when observing the expert lifts, which was eradicated when watching errors. Together, these findings suggest that individuals' sensorimotor systems are sensitive to the subtle visual differences between observing novice and expert performance.G. Buckingham was supported with a Banting Postdoctoral Fellowship, awarded by the Natural Sciences and Engineering Council of Canada (NSERC

Patient DF's visual brain in action : visual feedforward control in patient with visual form agnosia

Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF’s grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF’s performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF’s grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets, while in a second, the feedback was of a constant intermediate width while the visual target varied trial by trial. Despite such false feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF’s spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing

Multi-patch methods in general relativistic astrophysics - I. Hydrodynamical flows on fixed backgrounds

Many systems of interest in general relativistic astrophysics, including neutron stars, accreting compact objects in X-ray binaries and active galactic nuclei, core collapse, and collapsars, are assumed to be approximately spherically symmetric or axisymmetric. In Newtonian or fixed-background relativistic approximations it is common practice to use spherical polar coordinates for computational grids; however, these coordinates have singularities and are difficult to use in fully relativistic models. We present, in this series of papers, a numerical technique which is able to use effectively spherical grids by employing multiple patches. We provide detailed instructions on how to implement such a scheme, and present a number of code tests for the fixed background case, including an accretion torus around a black hole.Comment: 26 pages, 20 figures. A high-resolution version is available at http://www.cct.lsu.edu/~bzink/papers/multipatch_1.pd

An exploration of the impact of celebrity on the HIV/AIDS pandemic

The framework we present in this article separates into three generations the celebrity/personality involvement in the AIDS movement that has been steadily building momentum over the past 25 years. We analyze the celebrification of HIV/AIDS and the role of the media in the process. We contend the relationship between celebrity, the public and HIV/AIDS is multipurpose: celebrities maintain a positive public presence between projects while allowing themselves and their supporting fans to feel good about taking on and affecting a meaningful cause. Celebrities are vehicles and embodiments of concern that act as proxies for their various audiences. And this is their power–celebrities are embodiments of their audiences. The awareness that celebrities have brought to the HIV/AIDS epidemic has resulted in better treatment for victims and increased government support for medical research, and yet has also distracted the public’s attention from the scope of the epidemic. It is the third generation of celebrities who are refocusing efforts on worldwide prevention and a cure for HIV/AIDS