597 research outputs found

    The multisensory body revealed through its cast shadows

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    One key issue when conceiving the body as a multisensory object is how the cognitive system integrates visible instances of the self and other bodies with one\u2019s own somatosensory processing, to achieve self-recognition and body ownership. Recent research has strongly suggested that shadows cast by our own body have a special status for cognitive processing, directing attention to the body in a fast and highly specific manner. The aim of the present article is to review the most recent scientific contributions addressing how body shadows affect both sensory/perceptual and attentional processes. The review examines three main points: (1) body shadows as a special window to investigate the construction of multisensory body perception; (2) experimental paradigms and related findings; (3) open questions and future trajectories. The reviewed literature suggests that shadows cast by one\u2019s own body promote binding between personal and extrapersonal space and elicit automatic orienting of attention toward the bodypart casting the shadow. Future research should address whether the effects exerted by body shadows are similar to those observed when observers are exposed to other visual instances of their body. The results will further clarify the processes underlying the merging of vision and somatosensation when creating body representations

    Open Cluster Characterization via Cross-Correlation with Spectral Library

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    We present a characterization method based on spectral cross-correlation to obtain the physical parameters of the controversial stellar aggregate ESO442-SC04. The data used was obtained with GMOS at Gemini-South telescope including 17 stars in the central region of the ob ject and 6 standard-stars. FXCOR was used in an iterative process to obtain self-consistent radial velocities for the standard-stars and averaged radial velocities for the science spectra. Spectral types, effective temperature, suface gravity and metallicities parameters were determined using FXCOR to correlate cluster spectra with ELODIE spectral library and selecting the best correlation matches using the Tonry and Davis Ratio (TDR). Analysis of the results suggests that the stars in ESO442-SC04 are not bound and therefore they do not constitute a physical system.Comment: 4-page paper from IAU symposium 266. Contains 3 eps figures and IAU document class file 'iau.cls

    Training spatial hearing skills in virtual reality through a sound-reaching task

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    Sound localization is crucial for interacting with the surrounding world. This ability can be learned across time and improved by multisensory and motor cues. In the last decade, studying the contributions of multisensory and motor cues has been facilitated by the increased adoption of virtual reality (VR). In a recent study, sound localization had been trained through a task where the visual stimuli were rendered through a VR headset, and the auditory ones through a loudspeaker moved around by the experimenter. Physically reaching to sound sources reduced sound localization errors faster and to a greater extent if compared to naming sources’ positions. Interestingly, training efficacy extended also to hearing-impaired people. Yet, this approach is unfeasible for rehabilitation at home. Fullyvirtual approaches have been used to study spatial hearing learning processes, performing headphones-rendered acoustic simulations. In the present study, we investigate whether the effects of our reaching-based training can be observed when taking advantage of such simulations, showing that the improvement is comparable between the full-VR and blended VR conditions. This validates the use of training paradigms that are completely based on portable equipment and don’t require an external operator, opening new perspectives in the field of remote rehabilitation

    Peculiar spline collocation method for solving rough and stiff delay differential problems

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    As well known, solutions of delay differential equations (DDEs) are characterized by low regularity. In particular solutions of neutral delay differential equations (NDDEs) frequently exhibit discontinuities in the first derivative so that the differential problems become rough. The aim of this paper is to approximate the solutions of such rough delay differential problems by means of a peculiar deficient spline collocation method. Significant numerical examples are provided to enlighten the features of the proposed method

    The plasticity of near space: evidence for contraction

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    The distinction between near space and the space farther away has been well established, as has the relation of this distinction to arm length. Recent studies provide evidence for the plasticity of near space, showing that it is possible to expand its extent ("size") through tool-use. In the present study, we examine the converse effect, whether contraction of near space results from increasing the effort involved on a line bisection task. Adult participants bisected lines at different distances, while, in some cases, wearing weights. In Experiment 1, the arms, specifically, were weighted (wrist weights), and in Experiment 2, more general body weights were used (heavy backpack). As in previous studies, unencumbered participants showed leftward bias when bisecting lines at the closest distances and a rightward shift in bias with increasingly farther distances. With wrist weights, but not a heavy backpack, participants showed more rightward bias at the closest distances, and a more gradual rightward shift with increasing distance, as if the nearest locations were represented as being farther away. These results suggest that increased effort, when specifically related to the arm, can serve to reduce the size of near space, providing support for the generally symmetrical plasticity of near space representations

    UBVI CCD photometry and star counts in 9 inner disk Galactic star clusters

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    We present and discuss new CCD-based photometric material in the UBVI pass-bands for nine Galactic star clusters located inside the solar ring, for which no CCD data are currently available. They are: IC 2714, NGC 4052, ESO131SC09, NGC 5284, NGC 5316, NGC 5715, VdB-Hagen ~164, NGC 6268, and Czernik 38. We first perform star counts by combining our optical photometry wi th 2MASS, and derive cluster sizes and radial density profiles. The fundamental parameters - age, reddening and distance- are then inferred from the analysis of the star distribution in color-color and color-magnitude diagrams of only the spatially selected likely members. Our analysis shows that ESO131SC09, NGC 5284, and VdB-Hagen 164 are most probably not clusters, but random enhancements of a few bright stars along the line of sight, with prop erties much similar to open cluster remnants. The remaining clusters are physical groups, and are all younger than about 1 Gyr . We use the newly derived set of parameters, in particular distance and reddening, to investigate their position in the Galaxy in the context of the spiral structure of the Milky Way. We find that the youngest clusters (IC 2714, NGC 5316, and NGC 6268) are located close to or inside the Carina-Sagittarius arm, and are therefore {\i t bona fide} spiral structure tracers. On the other hand, the oldest (Czernik 38, NGC 4052, and NGC 5715) are floating in the inter-arm space between the Carina-Sagittarius and the more distant Scutum-Crux arm. Interestingly enough, the oldest clusters of this sample - Czernik 38 and NGC 5715- are among the few known open clusters to be older or as old as the Hyades in the inner Galactic disk, where star clusters are not expected to survive for a long time, because of the strong tidal field and the higher probability of close encounters .Comment: 17 pages, 11 eps figures, in press in MNRA

    Effect of zinc insertion and hydrophobicity on the membrane interactions and PDT activity of porphyrin photosensitizers

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    A series of photosensitizers (PS), which are meso-substituted tetra-cationic porphyrins, was synthesized in order to study the role of amphiphilicity and zinc insertion in photodynamic therapy (PDT) efficacy. Several properties of the PS were evaluated and compared within the series including photophysical properties (absorption spectra, fluorescence quantum yield U f , and singlet oxygen quantum yield U D ), uptake by vesicles, mitochondria and HeLa cells, dark and phototoxicity in HeLa cells. The photophysical properties of all compounds are quite similar (U f ≤ 0.02; U D~0 .8). An increase in lipophilicity and the presence of zinc in the porphyrin ring result in higher vesicle and cell uptake. Binding in mitochondria is dependent on the PS lipophilicity and on the electrochemical membrane potential, i.e., in uncoupled mitochondria PS binding decreases by up to 53%. The porphyrin substituted with octyl groups (TC8PyP) is the compound that is most enriched in mitochondria, and its zinc derivative (ZnTC8PyP) has the highest global uptake. The stronger membrane interaction of the zinc-substituted porphyrins is attributed to a complexing effect with phosphate groups of the phospholipids. Zinc insertion was also shown to decrease the interaction with isolated mitochondria and with the mitochondria of HeLa cells, an effect that has been explained by the particular characteristics of the mitochondrial internal membrane. Phototoxicity was shown to increase proportionally with membrane binding efficiency, which is attributed to favorable membrane interactions which allow more efficient membrane photooxidation. For this series of compounds, photodynamic efficiency is directly proportional to the membrane binding and cell uptake, but it is not totally related to mitochondrial targeting
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