Towards Immersive Virtual Reality Simulations of Bionic Vision

Bionic vision is a rapidly advancing field aimed at developing visual neuroprostheses ('bionic eyes') to restore useful vision to people who are blind. However, a major outstanding challenge is predicting what people 'see' when they use their devices. The limited field of view of current devices necessitates head movements to scan the scene, which is difficult to simulate on a computer screen. In addition, many computational models of bionic vision lack biological realism. To address these challenges, we propose to embed biologically realistic models of simulated prosthetic vision (SPV) in immersive virtual reality (VR) so that sighted subjects can act as 'virtual patients' in real-world tasks.Comment: 3 pages, 2 figures, to be presented at Augmented Human

Conscience and Attestation : The Methodological Role of the “Call of Conscience” (Gewissensruf) in Heidegger’s Being and Time

Travail réalisé en cotutelle (Université de Paris IV-La Sorbonne).Cette étude vise à exposer le rôle méthodologique que Martin Heidegger attribue à la conscience (Gewissen) dans Être et temps et à faire ressortir les implications de son interprétation de « l’appel de la conscience » comme le moyen de produire l’attestation (Bezeugung) de l’existence authentique en tant que possibilité du Dasein (ou être-dans-le-monde). Notre objectif initial est de montrer comment la notion heideggérienne de conscience a évolué avant la publication d’Être et temps en 1927 et d’identifier les sources qui ont contribué à l’interprétation existentiale de la conscience comme « l’appel du souci. » Notre analyse historique révèle notamment que Heidegger n’a jamais décrit la conscience comme un « appel » avant sa lecture du livre Das Gewissen (1925) par Hendrik G. Stoker, un jeune philosophe sud-africain qui a étudié à Cologne sous la direction de Max Scheler. Nous démontrons plus spécifiquement comment l’étude phénoménologique de Stoker—qui décrit la conscience comme « l’appel du devoir (Pflichtruf) » provenant de l’étincelle divine (synteresis) placée dans l’âme de chaque personne par Dieu—a influencé l’élaboration du concept de « l’appel existentiel » chez Heidegger. Mettant l’accent sur le rôle méthodologique de la conscience dans Être et temps, nous soulignons aussi l’importance des liens entre son concept de la conscience et la notion de « l’indication formelle » que Heidegger a mise au cœur de sa « méthode » dans ses cours sur la phénoménologie à Freiburg et Marbourg. Alors que de nombreux commentateurs voient dans « l’appel de la conscience » une notion solipsiste qui demeure impossible en tant qu’expérience, nous proposons un moyen de lever cette difficulté apparente en tentant de faire ressortir ce qui est « indiqué formellement » par la notion même de la conscience (Gewissen) dans Être et temps. Cette approche nous permet d’affirmer que le concept de conscience chez Heidegger renvoie à un phénomène de « témoignage » qui est radicalement différent de la notion traditionnelle de conscientia. Guidé par les principes mêmes de la phénoménologie heideggérienne, nous procédons à une analyse « destructrice » de l’histoire du mot allemand Gewissen qui nous révèle que la signification originelle de ce mot (établie dans le plus ancien livre préservé dans la langue allemande : le Codex Abrogans) était testimonium et non conscientia. À l’origine, Gewissen signifiait en effet « attestation »—ce qui est précisément le rôle assigné à la conscience par Heidegger dans Être et temps. Sur la base de cette découverte, nous proposons une manière de comprendre cette « attestation » comme une expérience possible : l’écoute du « témoignage silencieux » du martyr qui permet à Dasein de reconnaître sa propre possibilité d’authenticité.This study aims to exhibit the methodological role that Martin Heidegger assigns to conscience (Gewissen) in Being and Time and to reveal the implications of his interpretation of the “call of conscience” as the means of producing the attestation (Bezeugung) of authentic existence as a possibility of Being-in-the-world (or Dasein). We begin by seeking to understand how Heidegger’s notion of conscience evolved prior to the 1927 publication of Being and Time and to identify the sources which contributed to his interpretation of conscience as the “call of care.” Our historical analysis notably reveals that Heidegger never once describes conscience as a “call” before reading Das Gewissen (1925) by Hendrik G. Stoker, a young South African philosopher who studied under Max Scheler’s direction at the University of Cologne. We specifically examine how Stoker’s phenomenological study—which describes conscience as the “call-of-duty” issued to each human being by the divine “spark” (synteresis) placed in his or her soul by God—contributed to shaping Heidegger’s account of the “existential call.” Focusing on the methodological role of conscience in Being and Time, we analyze Heidegger’s major work in light of his early lectures on phenomenology at Freiburg and Marburg. This approach confirms the relation between conscience in Being and Time and the concept of “formal indication” that Heidegger placed at the heart of his evolving “method” of phenomenological investigation. While many commentators have argued that Heidegger’s “call of conscience” is solipsistic and impossible to experience, we propose a way of reconsidering this apparent impasse by examining what Being and Time itself “formally indicates” with regard to conscience. We show that Heidegger’s conscience points to a phenomenon of existential “testimony” which is radically different from the traditional notion of conscientia. Guided by Heidegger’s “formal indication” of conscience, we “destructively” review the history of the German word Gewissen and reveal its original meaning to be “testimonium” not “conscientia.” In recognizing that Gewissen originally meant “attestation,” we show how Heidegger’s existential phenomenon of conscience can be understood as Dasein’s experience of hearing the “silent testimony” of the martyr

A Systematic Review of Extended Reality (XR) for Understanding and Augmenting Vision Loss

Over the past decade, extended reality (XR) has emerged as an assistive technology not only to augment residual vision of people losing their sight but also to study the rudimentary vision restored to blind people by a visual neuroprosthesis. To make the best use of these emerging technologies, it is valuable and timely to understand the state of this research and identify any shortcomings that are present. Here we present a systematic literature review of 227 publications from 106 different venues assessing the potential of XR technology to further visual accessibility. In contrast to other reviews, we sample studies from multiple scientific disciplines, focus on augmentation of a person's residual vision, and require studies to feature a quantitative evaluation with appropriate end users. We summarize prominent findings from different XR research areas, show how the landscape has changed over the last decade, and identify scientific gaps in the literature. Specifically, we highlight the need for real-world validation, the broadening of end-user participation, and a more nuanced understanding of the suitability and usability of different XR-based accessibility aids. By broadening end-user participation to early stages of the design process and shifting the focus from behavioral performance to qualitative assessments of usability, future research has the potential to develop XR technologies that may not only allow for studying vision loss, but also enable novel visual accessibility aids with the potential to impact the lives of millions of people living with vision loss

A Wannier-function-based ab initio Hartree-Fock study of polyethylene

In the present letter, we report the extension of our Wannier-function-based ab initio Hartree-Fock approach---meant originally for three-dimensional crystalline insulators---to deal with quasi-one-dimensional periodic systems such as polymers. The system studied is all-transoid polyethylene, and results on optimized lattice parameters, cohesive energy and the band structure utilizing 6-31G** basis sets are presented. Our results are also shown to be in excellent agreement with those obtained with traditional Bloch-orbital-based approaches.Comment: 15 Pages, RevTex, inludes four figures, Chem. Phys. Letts., in press (1998

Continuous Gonadotropin-Releasing Hormone Infusion Stimulates Dramatic Gonadal Development in Hypogonadal Female Mice'

ABSTRACT Adult hypogonadal (hpg) mice, lacking GnRH, have infantile reproductive systems and levels of pituitary gonadotropins that are lower than normal. The mutant mice respond to brain grafts containing GnRH neurons with gonadal development and increased production of gonadotropins. In view of the substantial literature regarding the nature and necessity of pulsatile GnRH stimulation of gonadotropins, we were not surprised in earlier studies to find that the majority of hpg mice with successful grafts have pulsatile LH secretion. It is not known, however, why LH pulsatility was undetectable in some animals with significant gonadal development. The present experiment was intended to determine the degree to which hpg mice respond to continuous infusion of GnRH via osmotic minipumps. Unexpectedly, female hpg mice exhibited dramatic ovarian and uterine growth after 15 or 30 days of continuous exposure to GnRH, with five-and eightfold increases in ovarian and uterine weights, respectively. Despite evidence of increased gonadotropin secretion in the treated hpg mice, pituitary stores of FSH and LH remained low. Similar treatment of normal female mice for 15 days also depleted pituitary concentrations of LH and FSH without significantly altering gonadal weights or plasma gonadotropin levels. It is clear from the present findings that inferences of pulsatile GnRH secretion based on stimulation of gonadal development in hpg mice should be made with caution

International Health Regulations—What Gets Measured Gets Done

Focus on goals and metrics for 4 core capacities illustrates 1 approach to implementing IHR

Self-regulated charge transfer and band tilt in nm-scale polar GaN films

To date, the generic polarization of Bernardini, Fiorentini and Vanderbilt (PBFV) has been widely used to address the issue of polarity in III-V nitride semiconductors, but improvements in nitride materials and the performance of optoelectronic devices have been limited. The current first-principles calculation for the electronic structures of nm-scale [0001] GaN films show that the internal electric fields and the band tilt of these films are in opposite direction to those predicted by PBFV. Additionally, it is determined that an intrinsic self-regulated charge transfer across the film limits the electrostatic potential difference across the film, which renders the local conduction band energy minimum (at the Ga-terminated surface) approximately equal to the local valence band energy maximum (at the N-terminated surface). This effect is found to occur in films thicker than ~4nm

Differential expression analysis for sequence count data

*Motivation:* High-throughput nucleotide sequencing provides quantitative readouts in assays for RNA expression (RNA-Seq), protein-DNA binding (ChIP-Seq) or cell counting (barcode sequencing). Statistical inference of differential signal in such data requires estimation of their variability throughout the dynamic range. When the number of replicates is small, error modelling is needed to achieve statistical power.

*Results:* We propose an error model that uses the negative binomial distribution, with variance and mean linked by local regression, to model the null distribution of the count data. The method controls type-I error and provides good detection power. 

*Availability:* A free open-source R software package, _DESeq_, is available from the Bioconductor project and from "http://www-huber.embl.de/users/anders/DESeq":http://www-huber.embl.de/users/anders/DESeq

Van Hove Excitons and High-Tc_c Superconductivity: VIIIC Dynamic Jahn-Teller Effects vs Spin-Orbit Coupling in the LTO Phase of La2−x_{2-x}Srx_xCuO4_4

The possible role of the van Hove singularity (vHs) in stabilizing the low-temperature orthorhombic (LTO) phase transition in La$_{2-x}$\-Sr$_x$\-CuO$_ 4$ (LSCO) is discussed. It is found that the vHs can drive a structural distortion in two different ways, either due to spin-orbit coupling or to dynamic Jahn-Teller (JT) effects. This paper discusses the latter effect in some detail. It is shown that a model Hamiltonian introduced earlier to describe the coupled electron -- octahedral tilt motions (`cageons') has a series of phase transitions, from a high-temperature disordered JT phase (similar to the high-temperature tetragonal phase of LSCO) to an intermediate temperature dynamic JT phase, of average orthorhombic symmetry (the LTO phase) to a low temperature static JT phase (the low temperature tetragonal phase). For some parameter values, the static JT phase is absent.Comment: 28 pages plain TeX, 14 figures available upon request, NU-MARKIEWIC-93-0

Tight-binding parameters from the full-potential linear muffin-tin orbital method: A feasibility study on NiAl

We have examined a method of direct extraction of accurate tight-binding parameters from an ab-initio band-structure calculation. The linear muffin-tin potential method, in its full-potential implementation, has been used to provide the hamiltonian and overlap matrix elements in the momentum space. These matrix elements are Fourier transformed to real space to produce the tight-binding parameters. The feasibility of this method has been tested on the intermetallic alloy NiAl, using spd orbitals for each atom. The parameters generated for this alloy have been used as input to a real-space calculation of the local density of states using the recursion method.Comment: 12 pages, RevTex, 5 figure