An intuitive tangible game controller

This paper outlines the development of a sensory feedback device providing a low cost, versatile and intuitive interface for controlling digital environments, in this example a flight simulator. Gesture based input allows for a more immersive experience, so rather than making the user feel like they are controlling an aircraft the intuitive interface allows the user to become the aircraft that is controlled by the movements of the user's hand. The movements are designed to feel intuitive and allow for a sense of immersion that would be difficult to achieve with an alternative interface. In this example the user's hand can become the aircraft much the same way that a child would imagine it

Seeing with sound? Exploring different characteristics of a visual-to-auditory sensory substitution device

Sensory substitution devices convert live visual images into auditory signals, for example with a web camera (to record the images), a computer (to perform the conversion) and headphones (to listen to the sounds). In a series of three experiments, the performance of one such device (‘The vOICe’) was assessed under various conditions on blindfolded sighted participants. The main task that we used involved identifying and locating objects placed on a table by holding a webcam (like a flashlight) or wearing it on the head (like a miner’s light). Identifying objects on a table was easier with a hand-held device, but locating the objects was easier with a head-mounted device. Brightness converted into loudness was less effective than the reverse contrast (dark being loud), suggesting that performance under these conditions (natural indoor lighting, novice users) is related more to the properties of the auditory signal (ie the amount of noise in it) than the cross-modal association between loudness and brightness. Individual differences in musical memory (detecting pitch changes in two sequences of notes) was related to the time taken to identify or recognise objects, but individual differences in self-reported vividness of visual imagery did not reliably predict performance across the experiments. In general, the results suggest that the auditory characteristics of the device may be more important for initial learning than visual associations

Surface-reconstructed Icosahedral Structures for Lead Clusters

We describe a new family of icosahedral structures for lead clusters. In general, structures in this family contain a Mackay icosahedral core with a reconstructed two-shell outer-layer. This family includes the anti-Mackay icosahedra, which have have a Mackay icosahedral core but with most of the surface atoms in hexagonal close-packed positions. Using a many-body glue potential for lead, we identify two icosahedral structures in this family which have the lowest energies of any known structure in the size range from 900 to 15000 lead atoms. We show that these structures are stabilized by a feature of the many-body glue part of the interatomic potential.Comment: 9 pages, 8 figure

Uncomputably noisy ergodic limits

V'yugin has shown that there are a computable shift-invariant measure on Cantor space and a simple function f such that there is no computable bound on the rate of convergence of the ergodic averages A_n f. Here it is shown that in fact one can construct an example with the property that there is no computable bound on the complexity of the limit; that is, there is no computable bound on how complex a simple function needs to be to approximate the limit to within a given epsilon

Molecular dynamics simulations of lead clusters

Molecular dynamics simulations of nanometer-sized lead clusters have been performed using the Lim, Ong and Ercolessi glue potential (Surf. Sci. {\bf 269/270}, 1109 (1992)). The binding energies of clusters forming crystalline (fcc), decahedron and icosahedron structures are compared, showing that fcc cuboctahedra are the most energetically favoured of these polyhedral model structures. However, simulations of the freezing of liquid droplets produced a characteristic form of ``shaved'' icosahedron, in which atoms are absent at the edges and apexes of the polyhedron. This arrangement is energetically favoured for 600-4000 atom clusters. Larger clusters favour crystalline structures. Indeed, simulated freezing of a 6525-atom liquid droplet produced an imperfect fcc Wulff particle, containing a number of parallel stacking faults. The effects of temperature on the preferred structure of crystalline clusters below the melting point have been considered. The implications of these results for the interpretation of experimental data is discussed.Comment: 11 pages, 18 figues, new section added and one figure added, other minor changes for publicatio

Immersed nano-sized Al dispersoids in an Al matrix; effects on the structural and mechanical properties by Molecular Dynamics simulations

We used molecular dynamics simulations based on a potential model in analogy to the Tight Binding scheme in the Second Moment Approximation to simulate the effects of aluminum icosahedral grains (dispersoids) on the structure and the mechanical properties of an aluminum matrix. First we validated our model by calculating several thermodynamic properties referring to the bulk Al case and we found good agreement with available experimental and theoretical data. Afterwards, we simulated Al systems containing Al clusters of various sizes. We found that the structure of the Al matrix is affected by the presence of the dispersoids resulting in well ordered domains of different symmetries that were identified using suitable Voronoi analysis. In addition, we found that the increase of the grain size has negative effect on the mechanical properties of the nanocomposite as manifested by the lowering of the calculated bulk moduli. The obtained results are in line with available experimental data.Comment: 15 pages, 8 figures. Submitted to J. Phys: Condens. Matte

Isotopic dependence of the giant monopole resonance in the even-A ^{112-124}Sn isotopes and the asymmetry term in nuclear incompressibility

The strength distributions of the giant monopole resonance (GMR) have been measured in the even-A Sn isotopes (A=112--124) with inelastic scattering of 400-MeV $\alpha$ particles in the angular range $0^\circ$--$8.5^\circ$. We find that the experimentally-observed GMR energies of the Sn isotopes are lower than the values predicted by theoretical calculations that reproduce the GMR energies in $^{208}$Pb and $^{90}$Zr very well. From the GMR data, a value of $K_{\tau} = -550 \pm 100$ MeV is obtained for the asymmetry-term in the nuclear incompressibility.Comment: Submitted to Physical Review Letters. 10 pages; 4 figure

Use of ICD-10 codes for identification of injection drug use-associated infective endocarditis is nonspecific and obscures critical findings on impact of medications for opioid use disorder

Background: No International Classification of Diseases, 10th revision (ICD-10), diagnosis code exists for injection drug use-associated infective endocarditis (IDU-IE). Instead, public health researchers regularly use combinations of nonspecific ICD-10 codes to identify IDU-IE; however, the accuracy of these codes has not been evaluated. Methods: We compared commonly used ICD-10 diagnosis codes for IDU-IE with a prospectively collected patient cohort diagnosed with IDU-IE at Barnes-Jewish Hospital to determine the accuracy of ICD-10 diagnosis codes used in IDU-IE research. Results: ICD-10 diagnosis codes historically used to identify IDU-IE were inaccurate, missing 36.0% and misclassifying 56.4% of patients prospectively identified in this cohort. Use of these nonspecific ICD-10 diagnosis codes resulted in substantial biases against the benefit of medications for opioid use disorder (MOUD) with relation to both AMA discharge and all-cause mortality. Specifically, when data from all patients with ICD-10 code combinations suggestive of IDU-IE were used, MOUD was associated with an increased risk of AMA discharge (relative risk [RR], 1.12; 95% CI, 0.48-2.64). In contrast, when only patients confirmed by chart review as having IDU-IE were analyzed, MOUD was protective (RR, 0.49; 95% CI, 0.19-1.22). Use of MOUD was associated with a protective effect in time to all-cause mortality in Kaplan-Meier analysis only when confirmed IDU-IE cases were analyzed ( Conclusions: Studies using nonspecific ICD-10 diagnosis codes for IDU-IE should be interpreted with caution. In the setting of an ongoing overdose crisis and a syndemic of infectious complications, a specific ICD-10 diagnosis code for IDU-IE is urgently needed