A social Bayesian brain: how social knowledge can shape visual perception

A growing body of research suggests that social contextual factors such as desires and goals, affective states and stereotypes can shape early perceptual processes. We suggest that a generative Bayesian approach towards perception provides a powerful theoretical framework to accommodate how suchhigh-level social factors can influence low-level perceptual processes in their earliest stages. We review experimental findings that show how social factors shape the perception and evaluation of people, behaviour, and socially relevant objects or information. Subsequently, we summarize the generative view of perception within the ‘Bayesian brain’, and show how such a framework can account for the pervasive effects of top-down social knowledge on social cognition. Finally, we sketch the theoretical and experimental implications of social predictive perception, indicating new directions for research on the effects and neurocognitive underpinnings of social cognition

Varieties and regularities in the abundance patterns of the rareearth elements

Vision in the fovea, the center of the visual field, is much more accurate and detailed than vision in the periphery. This is not in line with the rich phenomenology of peripheral vision. Here, we investigated a visual illusion that shows that detailed peripheral visual experience is partially based on a reconstruction of reality. Participants fixated on the center of a visual display in which central stimuli differed from peripheral stimuli. Over time, participants perceived that the peripheral stimuli changed to match the central stimuli, so that the display seemed uniform. We showed that a wide range of visual features, including shape, orientation, motion, luminance, pattern, and identity, are susceptible to this uniformity illusion. We argue that the uniformity illusion is the result of a reconstruction of sparse visual information (from the periphery) based on more readily available detailed visual information (from the fovea), which gives rise to a rich, but illusory, experience of peripheral vision

Mid-range visual deficits after stroke:Prevalence and co-occurrence

Visual deficits are common after stroke and are powerful predictors for the chronic functional outcome. However, while basic visual field and recognition deficits are relatively easy to assess with standardized methods, selective deficits in visual primitives, such as shape or motion, are harder to identify, as they often require a symmetrical bilateral posterior lesion in order to provoke full field deficits. Therefore, we do not know how often they occur. Nevertheless, they can have severe repercussions for daily-life functioning. We aimed to investigate the prevalence and co-occurrence of hemifield “mid-range” visual deficits (i.e. color, shape, location, orientation, correlated motion, contrast, texture and glossiness), using a novel experimental set-up with a gaze-contingent presentation of the stimuli. To this end, a prospective cohort of 220 ischemic (sub)cortical stroke patients and a healthy control group was assessed with this set-up. When comparing performance of patients with controls, the results showed that deficits in motion-perception were most prevalent (26%), followed by color (22%), texture (22%), location (21%), orientation (18%), contrast (14%), shape (14%) and glossiness (13%). 63% of the stroke patients showed one or more mid-range visual deficits. Overlap of deficits was small; they mostly occurred in isolation or co-occurred with only one or two other deficits. To conclude, it was found that deficits in “mid-range” visual functions were very prevalent. These deficits are likely to affect the chronic post-stroke condition. Since we found no strong patterns of co-occurrences, we suggest that an assessment of deficits at this level of visual processing requires screening the full range of visual functions

No Evidence of Narrowly Defined Cognitive Penetrability in Unambiguous Vision

The classical notion of cognitive impenetrability suggests that perceptual processing is an automatic modular system and not under conscious control. Near consensus is now emerging that this classical notion is untenable. However, as recently pointed out by Firestone and Scholl, this consensus is built on quicksand. In most studies claiming perception is cognitively penetrable, it remains unclear which actual process has been affected (perception, memory, imagery, input selection or judgment). In fact, the only available “proofs” for cognitive penetrability are proxies for perception, such as behavioral responses and neural correlates. We suggest that one can interpret cognitive penetrability in two different ways, a broad sense and a narrow sense. In the broad sense, attention and memory are not considered as “just” pre- and post-perceptual systems but as part of the mechanisms by which top-down processes influence the actual percept. Although many studies have proven top-down influences in this broader sense, it is still debatable whether cognitive penetrability remains tenable in a narrow sense. The narrow sense states that cognitive penetrability only occurs when top-down factors are flexible and cause a clear illusion from a first person perspective. So far, there is no strong evidence from a first person perspective that visual illusions can indeed be driven by high-level flexible factors. One cannot be cognitively trained to see and unsee visual illusions. We argue that this lack of convincing proof for cognitive penetrability in the narrow sense can be explained by the fact that most research focuses on foveal vision only. This type of perception may be too unambiguous for transient high-level factors to control perception. Therefore, illusions in more ambiguous perception, such as peripheral vision, can offer a unique insight into the matter. They produce a clear subjective percept based on unclear, degraded visual input: the optimal basis to study narrowly defined cognitive penetrability

Split-Brain: what we know now and why this is important for understanding consciousness

Recently, the discussion regarding the consequences of cutting the corpus callosum (“split-brain”) has regained momentum (Corballis, Corballis, Berlucchi, & Marzi, 2018; Pinto et al., 2017; Pinto, Lamme, & de Haan, 2017; Volz & Gazzaniga, 2017; Volz, Hillyard, Miller, & Gazzaniga, 2018). This collective review paper aims to summarize the empirical common ground, to delineate the different interpretations, and to identify the remaining questions. In short, callosotomy leads to a broad breakdown of functional integration ranging from perception to attention. However, the breakdown is not absolute as several processes, such as action control, seem to remain unified. Disagreement exists about the responsible mechanisms for this remaining unity. The main issue concerns the first-person perspective of a split-brain patient. Does a split-brain harbor a split consciousness or is consciousness unified? The current consensus is that the body of evidence is insufficient to answer this question, and different suggestions are made to how future studies might address this paucity. In addition, it is suggested that the answers might not be a simple yes or no but that intermediate conceptualization need to be considered

Visual integration across fixation: automatic processes are split but conscious processes remain unified in the split-brain

The classic view holds that when “split-brain” patients are presented with an object in the right visual field, they will correctly identify it verbally and with the right hand. However, when the object is presented in the left visual field, the patient verbally states that he saw nothing but nevertheless identifies it accurately with the left hand. This interaction suggests that perception, recognition and responding are separated in the two isolated hemispheres. However, there is now accumulating evidence that this interaction is not absolute; for instance, split-brain patients are able to detect and localise stimuli anywhere in the visual field verbally and with either hand. In this study we set out to explore this cross-hemifield interaction in more detail with the split-brain patient DDC and carried out two experiments. The aim of these experiments is to unveil the unity of deliberate and automatic processing in the context of visual integration across hemispheres. Experiment 1 suggests that automatic processing is split in this context. In contrast, when the patient is forced to adopt a conscious, deliberate, approach, processing seemed to be unified across visual fields (and thus across hemispheres). First, we looked at the confidence that DDC has in his responses. The experiment involved a simultaneous “same” versus “different” matching task with two shapes presented either within one hemifield or across fixation. The results showed that we replicated the observation that split brain patients cannot match across fixation, but more interesting, that DDC was very confident in the across-fixation condition while performing at chance-level. On the basis of this result, we hypothesised a two-route explanation. In healthy subjects, the visual information from the two hemifields is integrated in an automatic, unconscious fashion via the intact splenium, and this route has been severed in DDC. However, we know from previous experiments that some transfer of information remains possible. We proposed that this second route (perhaps less visual; more symbolic) may become apparent when he is forced to use a deliberate, consciously controlled approach. In an experiment where he is informed, by a second stimulus presented in one hemifield, what to do with the first stimulus that was presented in the same or the opposite hemifield, we showed that there was indeed interhemispheric transfer of information. We suggest that this two-route model may help in clarifying some of the controversial issues in split-brain research

Characteristics and conditions of production of transient luminous events observed over a maritime storm

International audienceOn the night of 15/16 November 2007, cameras in southern France detected 30 transient luminous events (TLEs) over a storm located in the Corsican region (France). Among these TLEs, 19 were sprites, 6 were halos, and 5 were elves. For 26 of them, a positive “parent” cloud‐to‐ground lightning (P+CG) flash was identified. The peak current of the P+CG flashes for the sprites had an average value of 63 kA and had a maximum value of 125 kA. The flashes for the halos and the elves had average values of 272 and 351 kA, respectively, and they had maximum values of 312 and 384 kA, respectively. No TLEs were detected after negative CG flashes with very large peak currents. Among the 26 P+CG flashes, 23 were located in a stratiform region with reflectivity values lower than 45 dBZ. The CG flashes in this region were classified into two groups according to the time interval separating them from the following flash: one group with values less than 2 s and one with values greater than 2 s. About 79% of all CGs were produced in a sequence of at least two flashes less than 2 s apart. For 65.5% of the sequences, the first flash was positive with an average peak current of 73 kA, while the later +CG flashes in a sequence had much lower peak currents. Several triangulated sprites were found to be shifted from their P+CG flashes by about 10 to 50 km and preferentially downstream. The observations suggest that the P+CG flashes can initiate both sprites and other CG flashes in a storm

Obtención de clorofila a partir de cáscaras de sábila (Aloe barbadensis) por medio de solventes

Introduction: The increase in Aloe Vera as a raw material in the industry has led to a high generation of waste. The high content of chlorophyll contained in the peel can be extracted with solvents and applied as colorants in food-type agro-industry processes. Objective: Extract chlorophyll in the form of oleoresin by means of solvents from the shells of aloe (Aloe barbadensis) for use as a pigment. Method: Three solvents (acetone, ethanol and carbon tetrachloride) were used for the extraction of the chlorophyll contained in the Aloe Vera shell, keeping the fixed parameters of concentration, volume, centrifugation speed, optical density, temperature and storage time, comparing the total chlorophyll content and the antioxidant power by ABTS and DPPH with those obtained from a commercial sample. Results: The highest total chlorophyll content was 155.8 ml / g with acetone, this being the best extractive solvent, the antioxidant power test was 13826 ml equivalent of Trolox per 100 grams of raw material and 18125 mg eq. Trolox / 100g. Conclusions: Chlorophyll in the form of oleoresin extracted from aloe peels with acetone shows the best results compared to the use of ethanol and carbon tetrachloride as solvents.Introducción: El aumento del Aloe Vera como materia prima en la industria, ha conllevado a una alta generación de residuos. Los altos contenidos de clorofila contenidos en la cascara puede ser extraídos con solventes y ser aplicados como colorantes en los procesos de agroindustria de tipo alimentaria. Objetivo: Extraer clorofila en forma de oleorresina por medio de solventes a partir de las cáscaras de sábila (Aloe barbadensis). Metodología: Se usaron tres solventes (acetona, etanol y tetracloruro de carbono) para la extracción de la clorofila contenida en la cascara de Aloe Vera, mantenido los parámetros fijos de concentración, volumen, velocidad de centrifugado, densidad óptica, temperatura y tiempo de almacenamiento, comparando el contenido de clorofila total y el poder antioxidante por los métodos ABTS y DPPH, los cuales analizan la capacidad de atrapar radicales libres que son los responsables de la degradación oxidativa (DPPH - 2,2-Diphenyl-1-picryl-hidrazil), con los datos de capacidad antioxidante obtenidos de una muestra comercial.     Resultados: Comparando el contenido total de clorofila obtenido con los diferentes solventes, se encontró que el valor más alto fue 155,8 mL/g utilizando acetona, siendo este el mejor solvente extractivo, la prueba de poder antioxidante fue de 13826 mL equivalente de Trolox por 100 gramos de materia prima y 18125 mg eq. Trolox/100g.     Conclusiones: La clorofila en forma de oleorresina extraída de las cáscaras de sábila con acetona presenta los mejores resultados comparado con el uso de etanol y tetracloruro de carbono como solventes. &nbsp

Efecto de la inclusión de hojas de amaranto (Amaranthus dubius) en las propiedades de un yogurt frutado

The Amaranthus dubius is a herbaceous plant with high nutritional value thanks to its high content of protein, vitamins and minerals. Its agro-industrial use represents a food alternative, for which it is necessary to know the process parameters and the concentrations of use as raw material for the elaboration of a yogurt.Objective: To evaluate the effect of the inclusion of amaranth leaf flour on the properties of a fruity yogurt with soursop pulp (Annona muricata L.)Method: The production process was designed, incorporating the piglet in the form of flour. The time for humidity in equilibrium at 65 ° C was determined, the curve was adjusted to the Page model and four treatments were established (P, T1, T2, and T3), with piglet concentrations of 0%, 10%, 15 % and 20% respectively. A DCA (completely randomized design) was formulated, to evaluate the effect of the addition of flour, on the physicochemical, nutritional and sensory properties of fruity yogurt.Results: Equilibrium humidity was reached at 3h, with page model constants (C: 0,9585; K: 0,0133 and n: 2,2830). It was evidenced that pigtail improved the protein profile of the yogurt samples. In addition, the T3 formulation presented the highest protein content (7.93%), as well as vitamin C (0.15%), acidity (0.84%) and pH (4.21%). The formulations with the addition of milkweed showed a lower acceptance by the sensory panel.Conclusions: The incorporation of 20% amaranth leaf flour into the yogurt made it possible to increase the protein content by 6.21%, although the sensory properties should be improved.Introducción: El Amaranthus dubius es una planta herbácea de alto valor nutricional gracias a su alto tenido de proteína, vitaminas y minerales. Su aprovechamiento agroindustrial representa una alternativa alimenticia, para lo cual es necesario conocer los parámetros de proceso y las concentraciones de uso como materia prima para la elaboración de un yogurt. Objetivo:  Evaluar el efecto de la inclusión de harina de hojas de amaranto sobre las propiedades de un yogurt frutado con pulpa de guanábana (Annona muricata L.). Metodología: Se diseñó el proceso productivo, incorporando el bledo en forma de harina. Se determinó el tiempo para la humedad en equilibrio a 65°C, se ajustó la curva al modelo de Page y se establecieron cuatro tratamientos (P, T1, T2, y T3), con concentraciones de bledo de 0%, 10%, 15% y 20% respectivamente. Se formuló un DCA (diseño completamente al azar), Para evaluar el efecto de la adición de harina, sobre las propiedades fisicoquímicas, nutricionales y sensoriales del yogurt frutado. Resultados: Se alcanzó la humedad en equilibrio a las 3h, con constantes del modelo de page (C: 0,9585; K: 0,0133 y n: 2,2830). Se evidenció que el bledo mejoro el perfil proteico de las muestras de yogurt. Además, la formulación T3 presentó el contenido más alto de proteína (7,93%), así como la vitamina C (0,15%), acidez (0,84%) y pH (4,21%). Las formulaciones con adición de bledo presentaron una aceptación menor por parte del panel sensorial.      Conclusiones: La incorporación en el yogurt de 20% de harina de hojas de amaranto permitió incrementar en 6,21% el contenido de proteína, aunque deben mejorarse las propiedades sensoriales

Optimización de servicios y aplicaciones con nethserver

El documento es un articulo que describe las diferentes características y funciones que presenta el servidor NethServer ofreciendo opciones de solución en la red para una empresa en construcción. También en el articulo se puede encontrar el paso a paso para la instalación del servidor NethServer y algunas de sus herramientas importantes para su buen funcionamiento.The document is an article that describes the different features and functions that the NethServer server presents, offering network solution options for a company under construction. Also in the article you can find the step by step for installing the NethServer server and some of its important tools for its proper functioning