Rotationally actuated prosthetic helping hand

A prosthetic device has been developed for below-the-elbow amputees. The device consists of a cuff, a stem, a housing, two hook-like fingers, an elastic band for holding the fingers together, and a brace. The fingers are pivotally mounted on a housing that is secured to the amputee's upper arm with the brace. The stem, which also contains a cam, is rotationally mounted within the housing and is secured to the cuff, which fits over the amputee's stump. By rotating the cammed stem between the fingers with the lower arm, the amputee can open and close the fingers

Characterizing Distances of Networks on the Tensor Manifold

At the core of understanding dynamical systems is the ability to maintain and control the systems behavior that includes notions of robustness, heterogeneity, or regime-shift detection. Recently, to explore such functional properties, a convenient representation has been to model such dynamical systems as a weighted graph consisting of a finite, but very large number of interacting agents. This said, there exists very limited relevant statistical theory that is able cope with real-life data, i.e., how does perform analysis and/or statistics over a family of networks as opposed to a specific network or network-to-network variation. Here, we are interested in the analysis of network families whereby each network represents a point on an underlying statistical manifold. To do so, we explore the Riemannian structure of the tensor manifold developed by Pennec previously applied to Diffusion Tensor Imaging (DTI) towards the problem of network analysis. In particular, while this note focuses on Pennec definition of geodesics amongst a family of networks, we show how it lays the foundation for future work for developing measures of network robustness for regime-shift detection. We conclude with experiments highlighting the proposed distance on synthetic networks and an application towards biological (stem-cell) systems.Comment: This paper is accepted at 8th International Conference on Complex Networks 201

GameStop’s next play: reconfiguring the value offering

Theoretical basis The theoretical basis for this case is a focus on strategic positioning as related to Porter’s generic strategies. The case describes GameStop’s previous differentiation approach, executed through physical stores and knowledgeable staff. With technological shifts and the introduction of digital downloads, this strategy is less effective. The case requires students to consider how GameStop might revise its generic strategy based on the new competitive landscape in which it operates. Research methodology In writing this case, the research team conducted thorough analysis through primary data collection in stores as well as secondary data collection through the use of market research tools, such as IBIS World, MergentOnline, S&P Net Advantage, and academic journals, trade magazines, and websites. Case overview/synopsis With high uncertainty shown by stakeholders about the future of GameStop coupled with falling share prices, the company must find a way to stay in play given the rapidly growing digital gaming market. As it planned to close at least 150 of its 7,500 stores, the company was starting to take measures to reduce operational costs and restructure to sectors that best fit consumer interests. GameStop’s core competencies were no longer aligned with market conditions, and its executives were now questioning where it could expand the organization’s operations as they focused on finding untapped areas of the market that have an opportunity for a new competitive advantage. Given its unique market share in gaming memorabilia and trade-in values, students are tasked with finding GameStop’s existing competitive advantages or identifying potential new ones that can be leveraged in a technology-driven industry. Complexity academic level This case could be taught at either the graduate or undergraduate level strategy course. At the undergraduate level, it would be best taught when discussing industry life cycle or competitive dynamics. At the graduate level, MBAs could discuss competitive dynamics facing GameStop and how it might find areas for future strategic growth

Streaming success: positioning Roku’s future in a hypercompetitive industry

Theoretical basis The theoretical basis for this case is a focus on strategic positioning as related to Porter’s Generic Strategies. The case accounts Roku’s journey in facing additional competition, highlighting the competitive dynamics at play. The case requires students to consider how Roku might revise its generic strategy based on the new competitive landscape in which it operates. Research methodology In writing this case, the research team used secondary research that was informed by interviews with Roku users. Resources such as IBIS World, MergentOnline, academic journals, trade magazines and websites were used to inform and verify information. Case overview/synopsis As the market disruptor of how media was consumed, Roku had been connecting customers, publishes and advertisers with its unique capabilities for over 10 years. With the belief that all TV content should be available through streaming, Roku had forever changed the traditional model of how media was distributed and consumed. By capitalizing on the previously untapped economic opportunity of TV streaming platforms, Roku had made itself the premier streaming broadcast service for users, content publishers and advertisers. The company was now faced with the difficult task of finding the best ways to keep innovation high and continue to grow. Complexity academic level This case could be taught at either the graduate or undergraduate level strategy course. At the undergraduate level, it would be best taught in a strategy course, when discussing industry life cycle or vertical integration. At the graduate level, MBAs could discuss the competitive dynamics and hypercompetition within the industry

VLT Spectroscopy of Globular Clusters in Low Surface Brightness Dwarf Galaxies

We present VLT/FORS2 spectroscopic observations of globular clusters (GCs) in five low surface brightness (LSB) dwarf galaxies: KK211 and KK221, which are both dwarf spheroidal satellites (dSph) of NGC 5128, dSph KK84 located close to the isolated S0 galaxy NGC 3115, and two isolated dwarf irregular (dIrr) galaxies UGC 3755 and ESO 490-17. Our sample is selected from the Sharina et al. (2005) database of Hubble Space Telescope WFPC2 photometry of GC candidates in dwarf galaxies. For objects with accurate radial velocity measurements we confirm 26 as genuine GCs out of the 27 selected candidates from our WFPC2 survey. Lick absorption line indices in the spectra of confirmed GCs and the subsequent comparison with SSP model predictions show that all confirmed GCs in dSphs are old, except GC KK211-3-149 (6 +/- 2 Gyr), which we consider to be the nucleus of KK211. GCs in UGC 3755 and ESO 490-17 show a large spread in ages ranging from old objects (t > 10 Gyr) to clusters with ages around 1 Gyr. Most of our sample GCs have low metallicities [Z/H] <= -1. Two relatively metal-rich clusters with [Z/H] ~ -0.3 are likely to be associated with NGC 3115. Our sample GCs show in general a complex distribution of alpha-element enhancement with a mean [alpha/Fe]=0.19 +/-0.04 derived with the chi2 minimization technique and 0.18+/-0.12 dex computed with the iterative approach. These values are slightly lower than the mean [alpha/Fe]=0.29+/-0.01 for typical Milky Way GCs. We compare other abundance ratios with those of Local Group GCs and find indications for systematic differences in N and Ca abundance. The specific frequencies, S_N, of our sample galaxies are in line with the predictions of a simple mass-loss model for dwarf galaxies and compare well with S_N values found for dwarf galaxies in nearby galaxy clusters.Comment: accepted for publication in Ap

Love, rights and solidarity: studying children's participation using Honneth's theory of recognition

Recent attempts to theorize children’s participation have drawn on a wide range of ideas, concepts and models from political and social theory. The aim of this article is to explore the specific usefulness of Honneth’s theory of a ‘struggle for recognition’ in thinking about this area of practice. The article identifies what is distinctive about Honneth’s theory of recognition, and how it differs from other theories of recognition. It then considers the relevance of Honneth’s conceptual framework to the social position of children, including those who may be involved in a variety of ‘participatory’ activities. It looks at how useful Honneth’s ideas are in direct engagement with young people’s praxis, drawing on ethnographic research with members of a children and young people’s forum. The article concludes by reflecting on the implications of this theoretical approach and the further questions which it opens up for theories of participation and of adult–child relations more generally

Many-body spin related phenomena in ultra-low-disorder quantum wires

Zero length quantum wires (or point contacts) exhibit unexplained conductance structure close to 0.7 X 2e^2/h in the absence of an applied magnetic field. We have studied the density- and temperature-dependent conductance of ultra-low-disorder GaAs/AlGaAs quantum wires with nominal lengths l=0 and 2 mu m, fabricated from structures free of the disorder associated with modulation doping. In a direct comparison we observe structure near 0.7 X 2e^2/h for l=0 whereas the l=2 mu m wires show structure evolving with increasing electron density to 0.5 X 2e^2/h in zero magnetic field, the value expected for an ideal spin-split sub-band. Our results suggest the dominant mechanism through which electrons interact can be strongly affected by the length of the 1D region.Comment: 5 Pages, 4 figure

Ariel - Volume 4 Number 6

Editors David A. Jacoby Eugenia Miller Tom Williams Associate Editors Paul Bialas Terry Burt Michael Leo Gail Tenikat Editor Emeritus and Business Manager Richard J. Bonnano Movie Editor Robert Breckenridge Staff Richard Blutstein Mary F. Buechler J.D. Kanofsky Rocket Weber David Maye

Titan Science with the James Webb Space Telescope (JWST)

The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $\mu$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition and (v) stratospheric hazes. We discuss each theme in depth, including the scientific purpose, capabilities and limitations of the instrument suite, and suggested observing schemes. We pay particular attention to saturation, which is a problem for all three instruments, but may be alleviated for NIRCam through use of selecting small sub-arrays of the detectors - sufficient to encompass Titan, but with significantly faster read-out times. We find that JWST has very significant potential for advancing Titan science, with a spectral resolution exceeding the Cassini instrument suite at near-infrared wavelengths, and a spatial resolution exceeding HST at the same wavelengths. In particular, JWST will be valuable for time-domain monitoring of Titan, given a five to ten year expected lifetime for the observatory, for example monitoring the seasonal appearance of clouds. JWST observations in the post-Cassini period will complement those of other large facilities such as HST, ALMA, SOFIA and next-generation ground-based telescopes (TMT, GMT, EELT).Comment: 50 pages, including 22 figures and 2 table