Visual search with biological threat stimuli: Accuracy, reaction times, and heart rate changes.

Twenty-four participants were given a visual search task of deciding whether all the pictures in 3×3 search arrays contained a target picture from a deviant category, and heart rate was measured. The categories were snakes, spiders, flowers, and mushrooms. Shorter reaction times (RTs) were observed for fear-relevant (snake and spider) targets rather than for fear-irrelevant/neutral (flower and mushroom) targets. This difference was most pronounced for the participants presented with a gray-scale version of the search arrays. The 1st interbeat interval (IBI), after the search array onset, showed an effect of the target, whereas the 2nd IBI also showed an effect of the distractors. The results suggest that controlled processing of the task operates together with automatic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electric fields in the source region: the depolarization dyadic for a cubic cavity

Contents A closed-form expression for the depolarization dyadic is given for a cubic volume. With this dyadic, the singularity associated with the electromagnetic field calculation within the source region can be avoided. For the cubic volume, the dyadic depends on the position of the field point, unlike in the case of ellipsoidal volumes. The behaviour of the dyadic along the cube axes and diagonals is illustrated graphically.

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Elektrische Felder im Quellgebiet: Der Depolarisationstensor für einen kubischen Hohlraum

Übersicht Der Depolarisationstensor eines kubischen Volumens wird in geschlossener Form ausgedrückt. Mit diesem Tensor kann die Singularität vermieden werden, die bei der Berechnung des elektromagnetischen Feldes im Quellgebiet vorkommt. Anders als im Falle eines elliptischen Volumens ist der Tensor für einen kubischen Hohlraum von der Position innerhalb des Volumens abhängig. Das Verhalten des Tensors entlang der Achsen und entlang der Diagonalen des Würfels ist in graphischer Form dargestellt.

     

Prenatal expectations in transition to parenthood: Former infertility and family dynamic considerations.

Prenatal expectations are important for the future parent–child relationship. The authors examined how maternal and paternal prenatal expectations of the relationship with the child predicted 1st-year parenting stress and whether these expectations were violated over the transition to parenthood. They further examined how former infertility affected these associations. The participants were 745 Finnish couples, 367 having undergone a successful assisted reproductive treatment and 378 conceiving spontaneously. Couples completed a questionnaire of family representations during pregnancy and when the child was 2 and 12 months old and Abidin’s Parenting Stress Index at 2 and 12 months postpartum. The hypothesis of moderately high expectations predicting the lowest level of parenting stress was substantiated only concerning paternal expectations of own autonomy with the child. Generally, however, negative expectations of own and spouse’s relationship with the child were linearly associated with higher parenting stress. Postnatal representations were more positive or equal to expectations, except for negative violation occurring in maternal expectation of the father–child relationship, especially among normative mothers. The results are discussed in relation to family dynamic considerations and special features of formerly infertile couples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion drives attention: Detecting the snake in the grass.

Participants searched for discrepant fear-relevant pictures (snakes or spiders) in grid-pattern arrays of fear-irrelevant pictures belonging to the same category (flowers or mushrooms) and vice versa. Fear-relevant pictures were found more quickly than fear-irrelevant ones. Fear-relevant, but not fear-irrelevant, search was unaffected by the location of the target in the display and by the number of distractors, which suggests parallel search for fear-relevant targets and serial search for fear-irrelevant targets. Participants specifically fearful of snakes but not spiders (or vice versa) showed facilitated search for the feared objects but did not differ from controls in search for nonfeared fear-relevant or fear-irrelevant, targets. Thus, evolutionary relevant threatening stimuli were effective in capturing attention, and this effect was further facilitated if the stimulus was emotionally provocative. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DC potential anomalies caused by a conducting body in ananisotropic conducting half-space

Image theory for dc problems involving a current source in an anisotropic half-space bounded by either a perfectly magnetically conducting (PMC) or electrically conducting (PEC) plane is being used to get the solution for the potential in integral form. A dipole approximation for a small sphere is developed     

Image theory for DC problems involving a conducting half-spacebounded by a perfect anisotropic impedance surface

Image theory is developed for the canonical direct current problem involving a point current source in a conducting half-space bounded by a planar perfect anisotropic surface (PAS). The anisotropy of the surface is perfect in the sense that it has infinite conductivity in one direction and zero conductivity in the perpendicular direction. A PAS plane can be realized by a layer of perfectly conducting parallel wires isolated from one another. It is seen that the image of a current point source is a quadrupole transverse-magnetic current extending along a half-infinite line