Incremental grouping of image elements in vision

One important task for the visual system is to group image elements that belong to an object and to segregate them from other objects and the background. We here present an incremental grouping theory (IGT) that addresses the role of object-based attention in perceptual grouping at a psychological level and, at the same time, outlines the mechanisms for grouping at the neurophysiological level. The IGT proposes that there are two processes for perceptual grouping. The first process is base grouping and relies on neurons that are tuned to feature conjunctions. Base grouping is fast and occurs in parallel across the visual scene, but not all possible feature conjunctions can be coded as base groupings. If there are no neurons tuned to the relevant feature conjunctions, a second process called incremental grouping comes into play. Incremental grouping is a time-consuming and capacity-limited process that requires the gradual spread of enhanced neuronal activity across the representation of an object in the visual cortex. The spread of enhanced neuronal activity corresponds to the labeling of image elements with object-based attention

The Emergence of Emotions

Emotion is conscious experience. It is the affective aspect of consciousness. Emotion arises from sensory stimulation and is typically accompanied by physiological and behavioral changes in the body. Hence an emotion is a complex reaction pattern consisting of three components: a physiological component, a behavioral component, and an experiential (conscious) component. The reactions making up an emotion determine what the emotion will be recognized as. Three processes are involved in generating an emotion: (1) identification of the emotional significance of a sensory stimulus, (2) production of an affective state (emotion), and (3) regulation of the affective state. Two opposing systems in the brain (the reward and punishment systems) establish an affective value or valence (stimulus-reinforcement association) for sensory stimulation. This is process (1), the first step in the generation of an emotion. Development of stimulus-reinforcement associations (affective valence) serves as the basis for emotion expression (process 2), conditioned emotion learning acquisition and expression, memory consolidation, reinforcement-expectations, decision-making, coping responses, and social behavior. The amygdala is critical for the representation of stimulus-reinforcement associations (both reward and punishment-based) for these functions. Three distinct and separate architectural and functional areas of the prefrontal cortex (dorsolateral prefrontal cortex, orbitofrontal cortex, anterior cingulate cortex) are involved in the regulation of emotion (process 3). The regulation of emotion by the prefrontal cortex consists of a positive feedback interaction between the prefrontal cortex and the inferior parietal cortex resulting in the nonlinear emergence of emotion. This positive feedback and nonlinear emergence represents a type of working memory (focal attention) by which perception is reorganized and rerepresented, becoming explicit, functional, and conscious. The explicit emotion states arising may be involved in the production of voluntary new or novel intentional (adaptive) behavior, especially social behavior

Health risks due to emissions from the fire at a waste disposal site in The Netherlands

A large fire in May 2000 at a hazardous waste disposal site in Drachten (northern Netherlands), where waste included batteries, PCBs, insecticides and paint, has threatened a Netherlands dairy district. The Dutch National Institute of Public Health and the Environment (RIVM) and the State Institute for Quality Control of Agricultural products (RIKILT-DLO) were assigned the task of assessing potential human health risks due to the emissions by examining the contamination of grass - the staple food for cattle in summertime - and milk. Concentrations of contaminants in smoke were also examined to rule out inhalatory risks to the exposed population. Analyses showed that up to about 1000 m downwind of the fire, concentrations of heavy metals and dioxins in grass exceeded guidelines for animal food at several locations. However, due to the fact that (i) up to a distance of 1500 m downwind of the fire, the grass was cut and disposed of and (ii) the cattle had been kept inside for several days, concentrations of heavy metals and dioxins in milk did not exceed background concentrations. Dispersion modelling revealed that at a distance of 1000 m (the distance to the nearest dwellings), dilution of the smoke made risks to humans unlikely.Op vrijdag 12 mei 2000, omstreeks 08.00 uur, brak er brand uit bij het afval-verwerkingsbedrijf ATF De Pijp in Drachten. De belangrijkste vraag aan RIVM en RIKILT was of de emissies zouden kunnen leiden tot risico's voor de consument door het gebruik van verontreinigde melk en/of andere dierlijke producten uit het door depositie verontreinigde gebied. Daartoe zijn gras- en melkmonsters onderzocht op toxische stoffen. Tevens zijn de maximale concentraties van deze stoffen vastgesteld in de rook, zo dicht mogelijk bij de brand. De analyses lieten zien dat in het gras tot op een afstand van circa 1000 meter de normen voor veevoeder hier en daar werden overschreden. Echter als gevolg van de maatregelen - weideverbod tot 5000 m, maaien en afvoeren gras tot op een afstand van 1500 m - hebben de landbouwhuisdieren niet, of hooguit zeer kort, blootgestaan aan de gedeponeerde verontreinigingen. Dat wordt weerspiegeld in de melkmonsters, die geen van alle afwijkende gehaltes bevatten. De concentraties van een aantal componenten in de rook was duidelijk verhoogd ten opzichte van achtergrondwaarden en gezondheidkundige advieswaarden voor lange termijn blootstelling. Door de relatief grote afstand tot de eerste woonbebouwing, in combinatie met de beperkte duur van de brand (enkele uren), wordt de kans op blijvende effecten op de gezondheid ten gevolge van de inademing van de rook gering geacht. Over directe gezondheidseffecten die kunnen zijn opgetreden door inademing van rookgassen in de directe omgeving van de brand, kunnen geen uitspraken worden gedaan daar geen kwantitatieve meetgegevens beschikbaar zij

Health risks due to emissions from the fire at a waste disposal site in The Netherlands

Op vrijdag 12 mei 2000, omstreeks 08.00 uur, brak er brand uit bij het afval-verwerkingsbedrijf ATF De Pijp in Drachten. De belangrijkste vraag aan RIVM en RIKILT was of de emissies zouden kunnen leiden tot risico's voor de consument door het gebruik van verontreinigde melk en/of andere dierlijke producten uit het door depositie verontreinigde gebied. Daartoe zijn gras- en melkmonsters onderzocht op toxische stoffen. Tevens zijn de maximale concentraties van deze stoffen vastgesteld in de rook, zo dicht mogelijk bij de brand. De analyses lieten zien dat in het gras tot op een afstand van circa 1000 meter de normen voor veevoeder hier en daar werden overschreden. Echter als gevolg van de maatregelen - weideverbod tot 5000 m, maaien en afvoeren gras tot op een afstand van 1500 m - hebben de landbouwhuisdieren niet, of hooguit zeer kort, blootgestaan aan de gedeponeerde verontreinigingen. Dat wordt weerspiegeld in de melkmonsters, die geen van alle afwijkende gehaltes bevatten. De concentraties van een aantal componenten in de rook was duidelijk verhoogd ten opzichte van achtergrondwaarden en gezondheidkundige advieswaarden voor lange termijn blootstelling. Door de relatief grote afstand tot de eerste woonbebouwing, in combinatie met de beperkte duur van de brand (enkele uren), wordt de kans op blijvende effecten op de gezondheid ten gevolge van de inademing van de rook gering geacht. Over directe gezondheidseffecten die kunnen zijn opgetreden door inademing van rookgassen in de directe omgeving van de brand, kunnen geen uitspraken worden gedaan daar geen kwantitatieve meetgegevens beschikbaar zijnA large fire in May 2000 at a hazardous waste disposal site in Drachten (northern Netherlands), where waste included batteries, PCBs, insecticides and paint, has threatened a Netherlands dairy district. The Dutch National Institute of Public Health and the Environment (RIVM) and the State Institute for Quality Control of Agricultural products (RIKILT-DLO) were assigned the task of assessing potential human health risks due to the emissions by examining the contamination of grass - the staple food for cattle in summertime - and milk. Concentrations of contaminants in smoke were also examined to rule out inhalatory risks to the exposed population. Analyses showed that up to about 1000 m downwind of the fire, concentrations of heavy metals and dioxins in grass exceeded guidelines for animal food at several locations. However, due to the fact that (i) up to a distance of 1500 m downwind of the fire, the grass was cut and disposed of and (ii) the cattle had been kept inside for several days, concentrations of heavy metals and dioxins in milk did not exceed background concentrations. Dispersion modelling revealed that at a distance of 1000 m (the distance to the nearest dwellings), dilution of the smoke made risks to humans unlikely.HIM

Initiation of oral anticoagulant therapy in orthopedic and surgical patients:an algorithm compared with routine dosing

Oral anticoagulant therapy is initiated in most hospitals in The Netherlands by clinicians who routinely dose oral anticoagulants (without using an algorithm). This may explain the low proportion of patients leaving the hospital stabilized. To test this hypothesis this study compared the dosing of acenocoumarol in orthopedic and surgical patients using an algorithm with routine dosing. Because of the routine administration of low molecular weight heparin for at least the first 5 days of acenocoumarol therapy, the study focused on supra-therapeutic INR-values during this period. The study included 103 patients and was performed on orthopedic surgery and general surgery wards of a Dutch hospital over 5 months. The patients received acenocoumarol as an oral anticoagulant to prevent venous thromboembolism after general of orthopedic surgery. Patients were randomized into a group routinely dosed by physicians (n = 54) and a group dosed using a dosing algorithm (n = 49). A patient was defined as stable if he had two consecutive INR values within the range of 2-3 during hospitalization with the first (of the two consecutive INR values within range) having been measured on day 5 or later. The groups did not differ significantly in proportion of patients stabilized, time to stabilization, or length of hospitalization. In the first period (days 1-5) the routine dosing group had significantly more INR values above therapeutic range than the algorithm group, while the algorithm group had more INR values below the therapeutic range. There were two bleeding episodes in the routine dosing group and none in the algorithm group. Despite the lack of differences in stabilization between the two groups, this study suggests an advantage of dosing acenocoumarol using an algorithm in a study population consisting of prophylactically treated, mostly elderly orthopedic patients. The algorithm provides a safe dosing schedule for elderly postoperative patients who use low molecular weight heparin and NSAIDs concomitantly and are thus at high risk for bleeding complications