Aphanomyces astaci isolate from latently infected stone crayfish (Austropotamobius torrentium) population is virulent.

Aphanomyces astaci infection is the cause of crayfish plague in European crayfish. Here the virulence of an A. astaci As strain isolated from apparently healthy stone crayfish (Austropotamobius torrentium) from Slovenia was compared to that of the Psl-Puujärvi A.

Efficiency of temporal integration of sinusoidal flicker.

Purpose: Detection efficiency for flickering stimuli of constant duration decreases with increasing temporal frequency. Increasing frequency in this case also implies increasing number of flicker cycles. The current study was conducted to investigate whether this result could be due to the limited ability of the central detector to integrate flicker cycles.

Noise frame duration, masking potency and whiteness of temporal noise.

Purpose: Because of the limited contrast range, increasing the duration of the noise frame is often the only option for increasing the masking potency of external, white temporal noise. This, however, reduces the high-frequency cutoff beyond which noise is no longer white. This study was conducted to determine the longest noise frame duration that produces the strongest masking effect and still mimics white noise on the detection of sinusoidal flicker.

Scaling extrafoveal detection of distortion in a face and grating.

Peripheral performance involving simple visual tasks and stimuli can be equated with foveal performance by spatial scaling, whilst more complex tasks and stimuli seem to need additional scaling of image contrast. We therefore determined whether the contrast manipulation needed to compensate for eccentricity-dependent performance changes is due to an increase in stimulus or task difficulty. We measured contrast sensitivities to determine foveal and peripheral ability to discriminate between an original and a distorted version of a polar-circular sinusoidal grating and a face image.

The effect of contrast and size scaling on face perception in foveal and extrafoveal vision.

Purpose: To determine whether face perception can be equalized across the visual field by scaling size and contrast simultaneously.

Methods: Contrast sensitivities were measured for detection (N = 1) and identification (N = 2-8) of a target face as a function of size (0.4 degrees-10 degrees) across eccentricities (E = 0 degrees-10 degrees).