Spinal cord injury affects the interplay between visual and sensorimotor representations of the body.

The brain integrates multiple sensory inputs, including somatosensory and visual inputs, to produce a representation of the body. Spinal cord injury (SCI) interrupts the communication between brain and body and the effects of this deafferentation on body representation are poorly understood. We investigated whether the relative weight of somatosensory and visual frames of reference for body representation is altered in individuals with incomplete or complete SCI (affecting lower limbs' somatosensation), with respect to controls. To study the influence of afferent somatosensory information on body representation, participants verbally judged the laterality of rotated images of feet, hands, and whole-bodies (mental rotation task) in two different postures (participants' body parts were hidden from view). We found that (i) complete SCI disrupts the influence of postural changes on the representation of the deafferented body parts (feet, but not hands) and (ii) regardless of posture, whole-body representation progressively deteriorates proportionally to SCI completeness. These results demonstrate that the cortical representation of the body is dynamic, responsive, and adaptable to contingent conditions, in that the role of somatosensation is altered and partially compensated with a change in the relative weight of somatosensory versus visual bodily representations.

¿Pueden contribuir los métodos visuales a avanzar hacia una investigación inclusiva? Un estudio sobre inclusión sociolaboral con personas con Trastorno Mental Grave (TMG) = Can visual methods help to go forward inclusive research? A study about social and labor inclusion with people with Severe Mental Illness (SMI)

En este artículo se pretende mostrar cómo la utilización de métodos visuales en la investigación contribuye a potenciar la participación activa de las personas con TMG. Se utiliza como ejemplo un estudio de caso de corte cualitativo que incorpora tres actividades de componente visual (el dibujo “el río de la vida”, las fotografías y el dibujo de proyección de futuro) para favorecer la reflexión narrada que, sobre sus experiencias y vivencias, desarrollan cinco personas con TMG. El uso de las fotografías y dibujos en este estudio permite afirmar que estas estrategias se han mostrado válidas para acceder, en la medida que los participantes han querido, a esferas de vida personales en trayectorias vitales determinadas por la enfermedad mental

Accessing forgotten memory traces from long-term memory via visual movements

Because memory retrieval often requires overt responses, it is difficult to determine to what extend forgetting occurs as a problem in explicit accessing of long-term memory traces. In this study, we used eye-tracking measures in combination with a behavioural task that favoured high forgetting rates to investigate the existence of memory traces from long-term memory in spite of failure in accessing them consciously. In 2 experiments, participants were encouraged to encode a large set of sound-picture56 location associations. In a later test, sounds were presented and participants were instructed to visually scan, before a verbal memory report, for the correct location of the associated pictures in an empty screen. We found the reactivation of associated memories by sound cues at test biased oculomotor behaviour towards locations congruent with memory representations, even when participants failed to consciously provide a memory report of it. These findings reveal the emergence of a memory-guided behaviour that can be used to map internal representations of forgotten memories from long-term memory.

Orthoptic Sequelae Following Conservative Management of Pure Blowout Orbital Fractures: Anecdotal or Clinically Relevant?

The aim of this study was to prospectively assess the prevalence of orthoptic anomalies following conservative management of pure blowout orbital fractures and to evaluate their clinical relevance. Clinical and radiologic data of patients with unilateral conservatively managed pure blowout orbital fractures with a minimum follow-up of 6 months were reviewed. Eligible patients were contacted and invited to undergo an extended ophthalmologic examination as follows: distance and near visual acuities, Hertel exophthalmometry, corneal light reflex (Hirschberg test), ductions and versions in the 6 cardinal fields of gaze, eye deviation with prisms and alternate cover test in all of the 9-gaze directions with Maddox rod, degrees of incyclo/excyclotorsion with right and left eye fixation, horizontal and vertical deviation with Hess-Weiss coordimetry, degree of horizontal/vertical and incyclo/excyclotorsion deviation with Harms wall deviometry, and vertical deviation with Bielschowsky head-tilt test. Of the 69 patients contacted, 49 declined to participate given that they were asymptomatic. Twenty patients agreed to undergo the examination. One patient complained of minimal double vision limited to the extreme downgaze. Four patients had asymptomatic ocular motility disturbances limited to the extreme gaze. Seven patients had asymptomatic horizontal heterophoria. These disturbances did not interfere with daily or professional activities in any of the patients. The current study demonstrated that conservative management of pure orbital blowout fractures can result in orthoptic anomalies. These sequelae were restricted to a very limited portion of the binocular field of the vision and were not found to be clinically relevant.

L’art visual en els moviments pedagògics del segle XX: la concreció de l’educació artística en els llibres escolars

Les tradicions escolars d’educació artística s’han construït des de la transmissió oral i escrita de projectes i programes. Tanmateix, la concreció de les propostes legislatives, ideacionals i teòriques s’ha expressat, fonamentalment, a través dels documents. Tant és així que, per exemple, la cultura escolar a l’entorn de l’educació artística s’ha anat conformant des dels projectes codificats en els llibres per a mestres i per a infants. Per aquest motiu en aquest article es proposa una aproximació a aquests llibres a fi de conèixer quines són les característiques dels discursos de l’aprenentatge artístic que s’han consolidat al llarg del segle XX en el nostre entorn; aproximació que s’assaja a partir d’encreuar les petjades que han deixat els llibres escolars amb la seva imbricació o, fins i tot, negació amb les tendències de la pedagogia contemporània.

La memoria visual de la escuela

El artículo versa sobre la memoria visual de la escuela incidiendo tanto en las motivaciones que orientan la producción de imágenes como sobre el acercamiento a ellas que hoy podemos realizar. Parte así del análisis de los motivos de producción de imágenes según los períodos de la evolución escolar, prosigue una reseña de las distintas posibilidades de formación de memoria a través de las representaciones gráficas de la escuela y, finalmente, se plantean las principales características así como retos del tratamiento museológico y museográfico de la imagen escolar. El objetivo del artículo es, por lo tanto, realizar una aproximación a las imágenes concibiéndolas como bienes gráficos que requieren un avance en las formas de conservación, difusión e investigación que están desarrollando los centros de gestión del patrimonio educativo.

Development and validation of a visual grading scale for assessing image quality of AP pelvis radiographic images.

OBJECTIVE: The aim of this article was to apply psychometric theory to develop and validate a visual grading scale for assessing the visual perception of digital image quality anteroposterior (AP) pelvis. METHODS: Psychometric theory was used to guide scale development. Seven phantom and seven cadaver images of visually and objectively predetermined quality were used to help assess scale reliability and validity. 151 volunteers scored phantom images, and 184 volunteers scored cadaver images. Factor analysis and Cronbach's alpha were used to assess scale validity and reliability. RESULTS: A 24-item scale was produced. Aggregated mean volunteer scores for each image correlated with the rank order of the visually and objectively predetermined image qualities. Scale items had good interitem correlation (≥0.2) and high factor loadings (≥0.3). Cronbach's alpha (reliability) revealed that the scale has acceptable levels of internal reliability for both phantom and cadaver images (α = 0.8 and 0.9, respectively). Factor analysis suggested that the scale is multidimensional (assessing multiple quality themes). CONCLUSION: This study represents the first full development and validation of a visual image quality scale using psychometric theory. It is likely that this scale will have clinical, training and research applications. ADVANCES IN KNOWLEDGE: This article presents data to create and validate visual grading scales for radiographic examinations. The visual grading scale, for AP pelvis examinations, can act as a validated tool for future research, teaching and clinical evaluations of image quality.

Design of highly focused fields that remain unpolarized on axis

Research on the properties of highly focused fields mainly involved fully polarized light, whereas partially polarized waves received less attention. The aim of this Letter is to provide an appropriate framework, for designing some features of the focused field, when dealing with incoming partially polarized beams. In particular, in this Letter, we describe how to get an unpolarized field on the axis of a high numerical aperture objective lens. Some numerical results that corroborate theoretical predictions are provided.

Timing of visual stimuli in V1 and V5/MT: fMRI and TMS

Time perception is used in our day-to-day activities. While we understand quite well how our brain processes vision, touch or taste, brain mechanisms subserving time perception remain largely understudied. In this study, we extended an experiment of previous master thesis run by Tatiana Kenel-Pierre. We focused on time perception in the range of milliseconds. Previous studies have demonstrated the involvement of visual areas V1 and V5/MT in the encoding of temporal information of visual stimuli. Based on these previous findings the aim of the present study was to understand if temporal information was encoded in V1 and extrastriate area V5/MT in different spatial frames i.e., head- centered versus eye-centered. To this purpose we asked eleven healthy volunteers to perform a temporal discrimination task of visual stimuli. Stimuli were presented at 4 different spatial positions (i.e., different combinations of retinotopic and spatiotopic position). While participants were engaged in this task we interfered with the activity of the right dorsal V1 and the right V5/MT with transcranial magnetic stimulation (TMS). Our preliminary results showed that TMS over both V1 and V5/MT impaired temporal discrimination of visual stimuli presented at specific spatial coordinates. But whereas TMS over V1 impaired temporal discrimination of stimuli presented in the lower left quadrant, TMS over V5/MT affected temporal discrimination of stimuli presented at the top left quadrant. Although it is always difficult to draw conclusions from preliminary results, we could tentatively say that our data seem to suggest that both V1 and V5/MT encode visual temporal information in specific spatial frames.

Visual SLAM for 3D large-scale seabed acquisition employing underwater vehicles

This paper presents a novel technique to align partial 3D reconstructions of the seabed acquired by a stereo camera mounted on an autonomous underwater vehicle. Vehicle localization and seabed mapping is performed simultaneously by means of an Extended Kalman Filter. Passive landmarks are detected on the images and characterized considering 2D and 3D features. Landmarks are re-observed while the robot is navigating and data association becomes easier but robust. Once the survey is completed, vehicle trajectory is smoothed by a Rauch-Tung-Striebel filter obtaining an even better alignment of the 3D views and yet a large-scale acquisition of the seabed

Visual SLAM for underwater vehicles using video velocity log and natural landmarks

A visual SLAM system has been implemented and optimised for real-time deployment on an AUV equipped with calibrated stereo cameras. The system incorporates a novel approach to landmark description in which landmarks are local sub maps that consist of a cloud of 3D points and their associated SIFT/SURF descriptors. Landmarks are also sparsely distributed which simplifies and accelerates data association and map updates. In addition to landmark-based localisation the system utilises visual odometry to estimate the pose of the vehicle in 6 degrees of freedom by identifying temporal matches between consecutive local sub maps and computing the motion. Both the extended Kalman filter and unscented Kalman filter have been considered for filtering the observations. The output of the filter is also smoothed using the Rauch-Tung-Striebel (RTS) method to obtain a better alignment of the sequence of local sub maps and to deliver a large-scale 3D acquisition of the surveyed area. Synthetic experiments have been performed using a simulation environment in which ray tracing is used to generate synthetic images for the stereo system

Disseny d'una eina visual per a la configuració d'Iptables

Es dissenya una eina per configurar Iptables en una distribució de xarxa. L'eina permet a través d'una interfície gràfica definir una tipologia de xarxa i generar automàticament els scripts de configuració.

Reconstruction and analysis of surface variation using photometric stereo

In many industrial applications, accurate and fast surface reconstruction is essential for quality control. Variation in surface finishing parameters, such as surface roughness, can reflect defects in a manufacturing process, non-optimal product operational efficiency, and reduced life expectancy of the product. This thesis considers reconstruction and analysis of high-frequency variation, that is roughness, on planar surfaces. Standard roughness measures in industry are calculated from surface topography. A fast and non-contact method to obtain surface topography is to apply photometric stereo in the estimation of surface gradients and to reconstruct the surface by integrating the gradient fields. Alternatively, visual methods, such as statistical measures, fractal dimension and distance transforms, can be used to characterize surface roughness directly from gray-scale images. In this thesis, the accuracy of distance transforms, statistical measures, and fractal dimension are evaluated in the estimation of surface roughness from gray-scale images and topographies. The results are contrasted to standard industry roughness measures. In distance transforms, the key idea is that distance values calculated along a highly varying surface are greater than distances calculated along a smoother surface. Statistical measures and fractal dimension are common surface roughness measures. In the experiments, skewness and variance of brightness distribution, fractal dimension, and distance transforms exhibited strong linear correlations to standard industry roughness measures. One of the key strengths of photometric stereo method is the acquisition of higher frequency variation of surfaces. In this thesis, the reconstruction of planar high-frequency varying surfaces is studied in the presence of imaging noise and blur. Two Wiener filterbased methods are proposed of which one is optimal in the sense of surface power spectral density given the spectral properties of the imaging noise and blur. Experiments show that the proposed methods preserve the inherent high-frequency variation in the reconstructed surfaces, whereas traditional reconstruction methods typically handle incorrect measurements by smoothing, which dampens the high-frequency variation.