Differential susceptibility in youth: evidence that 5-HTTLPR x positive parenting is associated with positive affect 'for better and worse'.

Positive affect has been implicated in the phenomenological experience of various psychiatric disorders, vulnerability to develop psychopathology and overall socio-emotional functioning. However, developmental influences that may contribute to positive affect have been understudied. Here, we studied youths' 5-HTTLPR genotype and rearing environment (degree of positive and supportive parenting) to investigate the differential susceptibility hypothesis (DSH) that youth carrying short alleles of 5-HTTLPR would be more influenced and responsive to supportive and unsupportive parenting, and would exhibit higher and lower positive affect, respectively. Three independent studies tested this gene-environment interaction (GxE) in children and adolescents (age range 9-15 years; total N=1874). In study 1 (N=307; 54% girls), positive/supportive parenting was assessed via parent report, in study 2 (N=197; 58% girls) via coded observations of parent-child interactions in the laboratory and in study 3 (N=1370; 53% girls) via self report. Results from all the three studies showed that youth homozygous for the functional short allele of 5-HTTLPR were more responsive to parenting as environmental context in a 'for better and worse' manner. Specifically, the genetically susceptible youth (that is, S'S' group) who experienced unsupportive, non-positive parenting exhibited low levels of positive affect, whereas higher levels of positive affect were reported by genetically susceptible youth under supportive and positive parenting conditions. These GxE findings are consistent with the DSH and may inform etiological models and interventions in developmental psychopathology focused on positive emotion, parenting and genetic susceptibility.

Design of a lidar receiver with fiber-optic output.

Design considerations for a coaxial lidar receiver are examined, including details of coupling to an optical fiber for transfer of return light to a remote detector box. Attention is concentrated on the influence of fiber position on return-light capture efficiency and dynamic range of the return signal. The effect of a central obstruction on short-range signals is included. The analysis is augmented with simulations of lidar receiver performance.

Characteristics of the Sony Multiscan 17se Trinitron color graphic display.

Technical measurements of the Sony Multiscan 17se were made and are reported in the belief that they would be useful to visual scientists who consider employing this device as a display unit. Luminance, spatial uniformity, luminance additivity between the output of the guns, CIE1931 chromaticity coordinates, and gamma correction parameters were measured. The characteristics of individual monitors will probably be different from the one studied here but it is believed that the results obtained serve as a fair indication of what might be expected from this device.

Color appearance with sparse chromatic context.

We compared changes in the appearance of a test region caused by introducing an inhomogeneous chromatic background to changes caused by a space-averaged equivalent uniform background. Subjects adjusted a test field presented on a CRT so that it appeared neither reddish nor greenish. Sparse "white" or "green" dots, randomly scattered throughout a "red" background field, caused a large decrease (up to 15 nm) in the dominant wavelength of the red/green equilibrium setting, compared to measurements with a uniform "red" background. A uniform background with the same space-averaged chromaticity and luminance as the complex background had an effect similar to the uniform "red" background. These results contradict theories of color constancy that rely on the "gray world" assumption, and indicate the significance for color perception of individual chromaticities within discrete, noncontiguous regions.

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wave-sensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present. This may reflect the presence of a recombinant visual pigment protein or altered regulation of residual pigment genes, due to DNA changes--deletion of the long-wave pigment gene and reorganized sequences 5' to the pigment gene cluster--that segregate with the metabolic defect in this kindred.

Computing uses of the optical tunnel.

An optical tunnel configuration can perform crossover operations applicable to optical digital computing.

Fine structure of an image facsimile synthesized with a Gaussian spot.

A TV picture or any other line-scan image facsimile is anisotropic. Its intensity varies continuously along a sweep, and its resolution capability in this direction can be described by a modulation transfer function (MTF). In the orthogonal direction the facsimile's fine structure is discontinuous, and only discrete spatial frequencies can be reproduced. Such a system can be characterized by its MTF in the sweep direction and the ratio of its sweep interval and spot diameter. If the spot has a rotationally symmetric Gaussian intensitydistribution, the fine structure of the facsimile can be described in terms of the Gaussian spot profile. With a compatible relay-lens design, the optimum spot diameter for a CRT-to-film recording system is less than that for a directly viewed display.

The modulation transfer function of an optical system with a rotationally symmetric circle of confusion.

The relationship between an optical system's circle of confusion and the quality of the image it forms is not specified by any universally accepted criterion. However, a simple geometric theory helps place the problem in perspective. As a first-order approximation, the circle of confusion is considered to be a uniformly illuminated disk. Then the illumination at a point in the image is the average of the illumination which would occur in the geometric image within an aperture of finite diameter centered at this point in the image plane. If the circle of confusion has a more complex radial illumination distribution, the image-forming process can be considered as the combined operation of a number of concentric averaging apertures of varying radii. If the circle of confusion has a Gaussian radial illumination distribution, a solution for the modulation transfer function can be obtained in closed form.