Quantum nonlocality in two three-level systems

Recently a new Bell inequality has been introduced by Collins et al. [Phys. Rev. Lett. 88, 040404 (2002)], which is strongly resistant to noise for maximally entangled states of two d-dimensional quantum systems. We prove that a larger violation, or equivalently a stronger resistance to noise, is found for a nonmaximally entangled state. It is shown that the resistance to noise is not a good measure of nonlocality and we introduce some other possible measures. The nonmaximally entangled state turns out to be more robust also for these alternative measures. From these results it follows that two von Neumann measurements per party may be not optimal for detecting nonlocality. For d=3,4, we point out some connections between this inequality and distillability. Indeed, we demonstrate that any state violating it, with the optimal von Neumann settings, is distillable

Influence of alumina content and modifiers on phase separation in soda-lime-silica glass

The phase Separation behaviour of industrial soda-lime-silica glass is studied by visible light scattering. The main aspects which differentiate industrial glass from the ternary glass (composition in wt%): 76 SiO₂, 13 Na₂O, 11 CaO are considered. The obtained results show that the simple ternary glass easily develops phase Separation upon annealing at suitable temperature levels. Conversely, Container glass is stabilized against demixtion by the presence of a significant AI₂O₃ concentration, a significantly lower SiO₂ content and a more complex chemical formulation (partial Substitution of SiO₂, Na₂O and CaO with AI₂O₃, K₂O and MgO, respectively, as well as minor ingredients)

The architecture of information processing in biological systems

Biological systems process information at different scales and adapt to their changing environment. Informed both by experimental observations and theoretical constraints, we propose a chemical model for sensing that incorporates energy consumption, information storage, and negative feedback. We show that a biochemical architecture enclosing these minimal mechanisms leads to the emergence of dynamical memory and adaptation. Crucially, adaptation is associated with both an increase in the mutual information between external and internal variables and a reduction of dissipation of the internal chemical processes. By simultaneously minimizing energy consumption and maximizing information, we find that far-from-equilibrium sensing dominates in the low-noise regime. Our results, in principle, can be declined at different biological scales. We employ our model to shed light on large-scale neural adaptation in zebrafish larvae under repeated visual stimulation. We find striking similarities between predicted and observed behaviors, capturing the emergent adaptation of neural response. Our framework draws a path toward the unraveling of the essential ingredients that connect information processing, adaptation, and memory in biological systems

A cromestesia como ferramenta de ensino musical

Pode uma experiência sinestésica ser o ponto de partida para uma nova forma de notação musical? Utilizaremos um instrumento específico, a guitarra, como exemplo: tocar guitarra é uma tarefa que exige o uso simultâneo de vários sentidos: o sistema auditivo tem o papel princi pal e fundamental, pois permite a perceção das notas que estão a ser tocadas; a visão, por outro lado, orienta o músico ao longo do braço da guitarra, e traz o entendimento da repetição das notas no braço do instrumento. Já a sensação das cordas nas mãos, que influencia o vol ume, é transmitido pelo tato. Desta forma, pode-se afirmar que, ape sar de tocar guitarra ser uma atividade multissensorial, o resultando é principalmente uma experiência auditiva, e que quem não tem uma audição particularmente desenvolvida, está em desvantagem perante os restantes. Com esta premissa em consideração, a proposta deste trabalho con siste em aumentar o número de sentidos que reagem à vibração das cordas da guitarra, criando uma plataforma que identifica as notas, tal como um afinador, traduzindo-as para uma linguagem visual. Deste modo pretende-se auxiliar pessoas com deficiência auditiva ou com difi culdades em distinguir notas musicais a melhor perceber a utilização de um instrumento. Pretende-se que esta linguagem seja fundamentada em conceitos retirados de experiências sobre a cromestesia, a capaci dades que algumas pessoas possuem de “ver sons”, e sustentada com bases teóricas sobre o uso da cor como forma de melhor memorizar, explicadas através de estudos psicológicos. O bom funcionamento desta plataforma dependerá da correcta interpre tação da frequência de vibração das cordas do instrumento, através de qualquer receptor de áudio.Can a synesthetic experience be the starting point for a new form of musical notation? We will use a specific instrument, the guitar, as an ex ample: playing the guitar is a task that requires simultaneous use of var ious senses. The auditory system plays a primary and fundamental role, allowing the perception of the notes being played. The visual system guides the musician along the guitar neck and provides an understand ing of the repetition of notes on the instrument’s fretboard. Conversely, the sensation of the strings in the hands, influencing volume, is con veyed through the tactile system. Thus, it can be asserted that, despite playing the guitar being a multisensory activity, the result is primarily an auditory experience, and those without particularly developed hearing are at a disadvantage compared to others. With this premise in mind, this work aims to increase the number of senses that react to the vibration of the guitar strings, creating a platform that identifies the notes, much like a tuner, and translates them into a visual language. In this way, the goal is to assist individuals with hearing impairments or difficulties distinguishing musical notes to better under stand an instrument’s use. It is intended that this language be ground ed in concepts drawn from experiences with synesthesia, the ability of some individuals to “see sounds,” and supported by theoretical founda tions on the use of colour to improve memorization, explained through psychological studies. The proper functioning of this platform will depend on the accurate in terpretation of the vibration frequency of the instrument’s strings through any audio receptor

Simultaneous two-photon imaging and photo-stimulation with structured light illumination.

Holographic microscopy is increasingly recognized as a promising tool for the study of the central nervous system. Here we present a "holographic module", a simple optical path that can be combined with commercial scanheads for simultaneous imaging and uncaging with structured two-photon light. The present microscope is coupled to two independently tunable lasers and has two principal configurations: holographic imaging combined with galvo-steered uncaging and holographic uncaging combined with conventional scanning imaging. We applied this flexible system for simultaneous two-photon imaging and photostimulation of neuronal cells with complex light patterns, opening new perspectives for the study of brain function in situ and in vivo

Mechanical and Electrophysiological Properties of the Sarcolemma of Muscle Fibers in Two Murine Models of Muscle Dystrophy: Col6a1−/− and Mdx

This study aimed to analyse the sarcolemma of Col6a1−/− fibers in comparison with wild type and mdx fibers, taken as positive control in view of the known structural and functional alterations of their membranes. Structural and mechanical properties were studied in single muscle fibers prepared from FDB muscle using atomic force microscopy (AFM) and conventional electrophysiological techniques to measure ionic conductance and capacitance. While the sarcolemma topography was preserved in both types of dystrophic fibers, membrane elasticity was significantly reduced in Col6a1−/− and increased in mdx fibers. In the membrane of Col6a1−/− fibers ionic conductance was increased likely due to an increased leakage, whereas capacitance was reduced, and the action potential (ap) depolarization rate was reduced. The picture emerging from experiments on fibers in culture was consistent with that obtained on intact freshly dissected muscle. Mdx fibers in culture showed a reduction of both membrane conductance and capacitance. In contrast, in mdx intact FDB muscle resting conductance was increased while resting potential and ap depolarization rate were reduced, likely indicating the presence of a consistent population of severely altered fibers which disappear during the culture preparation

Targeted optogenetic stimulation to study the computational properties in neuronal ensembles recorded by multi-electrode devices

Micro-electrode array (MEA) technology has been exploited as a powerful tool for providing distributed information on learning, memory and information processing in cultured neuronal tissue, enabling an experimental perspective from the single cell level up to the scale of complex biological networks. An integral part in the use of MEAs involves the need to apply a local stimulus to stimulate or modulate the activity of certain regions of the tissue down to the single neuron level. Currently, this presents various limitations due to the low spatial resolution of the electrical stimulation. The recent development of optogenetic probes enables for the opportunity to switch from a full electrical paradigm to a combination of a reliable optical stimulation, including excitation and inhibition, coupled to large scale recordings based on MEA. In order to take full advantage from the expression of such optical tools, the capability of properly shaping the optical stimulation pattern has to be developed to fit at the same time either the single neuron targeting or multi site/large area stimulation. The design of a versatile patterned light projection device is an essential step towards this goal. Digital micro-mirrors devices (DMDs) spatial light modulators became recently available a tools for spatial mapped fluorescence measurements, photo-patterning, molecule uncaging and high resolution imaging. Here we describe a two-wavelength spatial light projection system for real-time closed loop modulation of neuronal activity, which is able to trigger a specific protocol of optical stimulation (space, time, wavelengths) by properly configuring the DMD upon detection of typical patterns (space and time) of electrical activation recorded with MEA. By adopting such an approach, it will be possible to better understand the fundamental mechanisms underlying the propagation and processing of the information in distinct neuronal subareas or subpopulations and their specific roles within in-vitro or ex-vivo neuronal networks

A cellular-resolution atlas of the larval zebrafish brain

Understanding brain-wide neuronal dynamics requires a detailed map of the underlying circuit architecture. We built an interactive cellular-resolution atlas of the zebrafish brain at 6 days post-fertilization (dpf) based on the reconstructions of over 2,000 individually GFP-labeled neurons. We clustered our dataset in "morphotypes,'' establishing a unique database of quantitatively described neuronal morphologies together with their spatial coordinates in vivo. Over 100 transgene expression patterns were imaged separately and co-registered with the single-neuron atlas. By annotating 72 non-overlapping brain regions, we generated from our dataset an inter-areal wiring diagram of the larval brain, which serves as ground truth for synapse-scale, electron microscopic reconstructions. Interrogating our atlas by "virtual tract tracing'' has already revealed previously unknown wiring principles in the tectum and the cerebellum. In conclusion, we present here an evolving computational resource and visualization tool, which will be essential to map function to structure in a vertebrate brain

A novel sensor for ion electron emission microscopy

Abstract An ion electron emission microscope (IEEM) to be installed at the SIRAD heavy ion irradiation facility at the 15 MV tandem accelerator of the INFN Legnaro laboratory (Italy) will be used to characterize the sensitivity of electronic devices to single event effects (SEE) to ion impacts with micrometric lateral resolutions. The secondary electrons emitted by ion impacts from the target surface are transported and focused by an electron microscope onto a micro-channel plate (MCP) detector coupled to a fast phosphor. The luminous signal is then detected by a position sensitive photon detector located outside the vacuum chamber. The high repetition rates and high spatial resolution, required to temporally distinguish ion impacts for SEE studies and avoid degrading of the initial resolution of the IEEM and MCP are met by the system, presented here for the first time, based on two orthogonal linear CCDs