Amodal completion in visual working memory

Amodal completion refers to the perceptual “filling-in” of partly occluded object fragments. Previous work has shown that object completion occurs efficiently, at early perceptual stages of processing. However, despite efficient early completion, at a later stage, the maintenance of complete-object representations in visual working memory (VWM) may be severely restricted due to limited mnemonic resources being available. To examine for such a limitation, we investigated whether the structure of to-be-remembered objects influences what is encoded and maintained in VWM using a change detection paradigm. Participants were presented with a memory display that contained either “composite” objects, that is, notched shapes abutting an occluding square, or equivalent unoccluded, “simple” objects. The results showed overall increased memory performance for simple relative to composite objects. Moreover, evidence for completion in VWM was found for composite objects that were interpreted as globally completed wholes, relative to local completions or an uncompleted mosaic (baseline) condition. This global completion advantage was obtained only when the “context” of simple objects also supported a global object interpretation. Finally, with an increase in memory set size, the global object advantage decreased substantially. These findings indicate that processes of amodal completion influence VWM performance until some overall-capacity limitation prevents completion. VWM completion processes do not operate automatically; rather, the representation format is determined top-down based on the simple object context provided. Overall, these findings support the notion of VWM as a capacity-limited resource, with storage capacity depending on the structured representation of to-be-remembered objects

An annotated checklist of the jumping plant-lice (Insecta: Hemiptera: Psylloidea) from the Mercantour National Park, with seven new records for France and one new synonymy

A total of 68 psyllid species are listed from the Mercantour National Park in Southeast France, where a targeted collecting campaign was conducted between 2009 and 2012, as part of the project "ATBI+M" Mercantour. The insects were collected using Malaise traps, flight intercept traps and sweep nets to sample in the vegetation. Additional information on distribution, biology and host-plants is provided for each species. Seven species are recorded for the first time from France: Craspedolepta artemisiae (Foerster, 1848), Craspedolepta nebulosa (Zetterstedt, 1828), Cacopsylla propinqua (Schaefer, 1949), Cyamophila prohaskai (Priesner, 1927), Eryngiofaga cf. refuga (Loginova, 1966), Bactericera parastriola Conci, Ossiannilsson & Tamanini, 1988 and Trioza flixiana Burckhardt & Lauterer, 2002. Trioza (Trioza) rapisardai Conci & Tamanini, 1984 is a new subjective synonym of Trioza brachyceraea Hodkinson & White, 1979, which was previously known only from the male holotype. The abundance, distribution and introduction status of some species are discussed

Surface filling-in and contour interpolation contribute independently to Kanizsa figure formation

To explore mechanisms of object integration, the present experiments examined how completion of illusory contours and surfaces modulates the sensitivity of localizing a target probe. Observers had to judge whether a briefly presented dot probe was located inside or outside the region demarcated by inducer elements that grouped to form variants of an illusory, Kanizsa-type figure. From the resulting psychometric functions, we determined observers' discrimination thresholds as a sensitivity measure. Experiment 1 showed that sensitivity was systematically modulated by the amount of surface and contour completion afforded by a given configuration. Experiments 2 and 3 presented stimulus variants that induced an (occluded) object without clearly defined bounding contours, which gave rise to a relative sensitivity increase for surface variations on their own. Experiments 4 and 5 were performed to rule out that these performance modulations were simply attributable to variable distances between critical local inducers or to costs in processing an interrupted contour. Collectively, the findings provide evidence for a dissociation between surface and contour processing, supporting a model of object integration in which completion is instantiated by feedforward processing that independently renders surface filling-in and contour interpolation and a feedback loop that integrates these outputs into a complete whole

Kanizsa-figure object completion gates selection in the attentional blink

Previous work has demonstrated that perceptual grouping modulates the selectivity of attention across space. By contrast, how grouping influences the allocation of attention over time is much less clear. This study investigated this issue, using an attentional blink (AB) paradigm to test how grouping influences the initial selection and the subsequent short-term memory consolidation of a target. On a given trial, two red Kanizsa-type targets (T1 and T2) with varying grouping strength were embedded in a rapid serial visual presentation stream of irrelevant distractors. Our results showed the typical AB finding: impaired identification of T2 when presented close in time following T1. Moreover, the AB was modulated by the T2 grouping?independently of the T1 structure?with stronger grouping leading to a decreased AB and overall higher performance. Conversely, a reversed pattern, namely an increased AB with increasing grouping strength was observed when the Kanizsa figure was not task-relevant. Together, these findings suggest that the grouping benefit emerges at early perceptual stages, automatically drawing attentional resources, thereby leading to either sustained benefits or transient costs?depending on the task-relevance of the grouped object. This indicates that grouping modulates processing of objects in time

Linking generalized parton distributions to constituent quark models

The link between the nucleon generalized parton distributions and the non-diagonal one-body density matrix in momentum space is studied. Attention is focussed on the region where quark generalized parton distributions (GPD's) describe emission and reabsorption of a single active quark by the target nucleon. The correct covariant connection with wave functions used in any constituent quark model is established. Results obtained with different constituent quark models are presented for the unpolarized quark GPD's.Comment: 2 new figures included and references added, conclusions unchanged. Version to appear in Nucl. Phys.

Análisis químico y sensorial de maní tostado cubierto con arrope de tuna y de algarrobo

The objective of this work was to determine the chemical composition, sensory attributes and consumer acceptance of roasted peanuts coated with prickly pear (RP-P) and “algarrobo” pod syrups (RP-A). Roasted peanuts (RP) without coating had the highest oil content (50.4%) in comparison with the coated products RP-P and RP-A (45.3% and 46.7%, respectively). RP-P and RP-A showed lower protein percentage and higher carbohydrate content than RP. These results affected the energy values of the products: 6.14 kcal/g in RP-P, 6.24 kcal/g in RP-A and 6.42 kcal/g in RP. In the consumer test, RP and RP-P had higher consumer acceptance for the attributes of color, texture and flavor than RP-A. In the descriptive analysis, RP-P and RPA showed higher intensity ratings in brown color, roughness, glossy, powdery, sweetness, and salty sensory attributes and lower intensity ratings in raw/beany flavor than in RP. The intensity of roasted peanutty flavor and the texture attributes in the descriptive analysis were not affected for the pod syrup coating.El objetivo del trabajo fue determinar la composición química, atributos sensoriales y la aceptabilidad del maní tostado cubierto con arrope de tuna (RP-P) y de Algarrobo (RP-A). El maní tostado sin cobertura presentó el mayor contenido de aceite (50,4%) en comparación con los maníes cubiertos, RPP y RP-A (45,3% y 46,7%, respectivamente). RP-P y RP-A mostraron menor porcentaje de proteína y mayor contenido de hidratos de carbonos que RP. Estos resultados afectaron los valores energéticos de los productos: 6,14 kcal/g in RP-P, 6,24 kcal/g in RP-A y 6,42 kcal/g in RP. En la prueba de consumidores, RP y RP-P tuvieron mayor aceptabilidad para los atributos color, textura y sabor que en RP-A. En la prueba descriptiva, RP-P y RP-A mostraron mayores intensidades en los atributos sensoriales de color marrón, rugosidad, brillo, pulverulencia, dulzor y salado y menor intensidad en sabor crudo/ poroto que en RP. Las intensidades del sabor a maní tostado y de los atributos de texturas en el análisis descriptivo no fueron afectadas por la presencia de la cobertura de arrope

Microlenses fabricated by two-photon laser polymerization for cell imaging with non-linear excitation microscopy

Non-linear excitation microscopy offers several advantages for in-vivo imaging compared to conventional confocal techniques. However, tissue penetration can still be an issue due to scattering and spherical aberrations induced on focused beams by the tissue. The use of low numerical aperture objectives to pass through the outer layers of the skin, together with high dioptric power microlenses implanted in-vivo close to the observation volume, can be beneficial to the reduction of optical aberrations. Here, Fibroblast cell culture plano-convex microlenses to be used for non-linear imaging of biological tissue are developed and tested. The microlenses can be used as single lenses or multiplexed in an array. A thorough test of the lenses wavefront is reported together with the modulation transfer function and wavefront profile. Magnified fluorescence images can be retrieved through the microlenses coupled to commercial confocal and two-photon excitation scanning microscopes. The signal-to-noise ratio of the images is not substantially affected by the use of the microlenses and the magnification can be adjusted by changing the relative position of the microlens array to the microscope objective and the immersion medium. These results are opening the way to the application of implanted micro-optics for optical in-vivo inspection of biological processes

Point-of-care assessment of platelet reactivity in the emergency department may facilitate rapid rule-out of acute coronary syndromes: a prospective cohort pilot feasibility study

Objective: Accurate, efficient and cost-effective disposition of patients presenting to emergency departments (EDs) with symptoms suggestive of acute coronary syndromes (ACS) is a growing priority. Platelet activation is an early feature in the pathogenesis of ACS; thus, we sought to obtain an insight into whether point-of-care testing of platelet function: (1) may assist in the rule-out of ACS; (2) may provide additional predictive value in identifying patients with non-cardiac symptoms versus ACS-positive patients and (3) is logistically feasible in the ED. Design: Prospective cohort feasibility study. Setting: Two urban tertiary care sites, one located in the USA and the second in Argentina. Participants: 509 adult patients presenting with symptoms of ACS. Main outcome measures Platelet reactivity was quantified using the Platelet Function Analyzer-100, with closure time (seconds required for blood, aspirated under high shear, to occlude a 150 µm aperture) serving as the primary endpoint. Closure times were categorised as ‘normal’ or ‘prolonged’, defined objectively as the 90th centile of the distribution for all participants enrolled in the study. Diagnosis of ACS was made using the standard criteria. The use of antiplatelet agents was not an exclusion criterion. Results: Closure times for the study population ranged from 47 to 300 s, with a 90th centile value of 138 s. The proportion of patients with closure times ≥138 s was significantly higher in patients with non-cardiac symptoms (41/330; 12.4%) versus the ACS-positive cohort (2/105 (1.9%); p=0.0006). The specificity of ‘prolonged’ closure times (≥138 s) for a diagnosis of non-cardiac symptoms was 98.1%, with a positive predictive value of 95.4%. Multivariate analysis revealed that the closure time provided incremental, independent predictive value in the rule-out of ACS. Conclusions: Point-of-care assessment of platelet reactivity is feasible in the ED and may facilitate the rapid rule-out of ACS in patients with prolonged closure times

Chemical composition and sensory analysis of roasted peanuts coated with prickly pear and algarrobo pod syrups

The objective of this work was to determine the chemical composition, sensory attributes and consumer acceptance of roasted peanuts coated with prickly pear (RP-P) and “algarrobo” pod syrups (RP-A). Roasted peanuts (RP) without coating had the highest oil content (50.4%) in comparison with the coated products RP-P and RP-A (45.3% and 46.7%, respectively). RP-P and RP-A showed lower protein percentage and higher carbohydrate content than RP. These results affected the energy values of the products: 6.14 kcal/g in RP-P, 6.24 kcal/g in RP-A and 6.42 kcal/g in RP. In the consumer test, RP and RP-P had higher consumer acceptance for the attributes of color, texture and flavor than RP-A. In the descriptive analysis, RP-P and RPA showed higher intensity ratings in brown color, roughness, glossy, powdery, sweetness, and salty sensory attributes and lower intensity ratings in raw/beany flavor than in RP. The intensity of roasted peanutty flavor and the texture attributes in the descriptive analysis were not affected for the pod syrup coating.El objetivo del trabajo fue determinar la composición química, atributos sensoriales y la aceptabilidad del maní tostado cubierto con arrope de tuna (RP-P) y de Algarrobo (RP-A). El maní tostado sin cobertura presentó el mayor contenido de aceite (50,4%) en comparación con los maníes cubiertos, RPP y RP-A (45,3% y 46,7%, respectivamente). RP-P y RP-A mostraron menor porcentaje de proteína y mayor contenido de hidratos de carbonos que RP. Estos resultados afectaron los valores energéticos de los productos: 6,14 kcal/g in RP-P, 6,24 kcal/g in RP-A y 6,42 kcal/g in RP. En la prueba de consumidores, RP y RP-P tuvieron mayor aceptabilidad para los atributos color, textura y sabor que en RP-A. En la prueba descriptiva, RP-P y RP-A mostraron mayores intensidades en los atributos sensoriales de color marrón, rugosidad, brillo, pulverulencia, dulzor y salado y menor intensidad en sabor crudo/ poroto que en RP. Las intensidades del sabor a maní tostado y de los atributos de texturas en el análisis descriptivo no fueron afectadas por la presencia de la cobertura de arrope