Narrow Results

This study investigated whether the effect of circadian effect can be characterized by midnight pupil size. A phosphor-converted LED and an RGB LED with the same photopic luminance and color temperatures but different circadian luminance were selected as the experimental light sources. The steady-state pupil diameters stimulated by these two LEDs’ lighting were obtained by the infrared video, which were affected by photopic and circadian effects together. Twenty healthy volunteers were tested at different times of a day for five working days. It was found that the steady-state pupil size stimulated by these two LEDs were significantly different at midnight, but showed no significant difference in daytime, which indicated the circadian effect can be characterized by midnight pupil size. This study was very important for the design and evaluation of healthy lighting.

Current model for circadian rhythms is wrong both theoretically and practically. A new model, called yin yang model, is proposed to explain the mechanism of circadian rhythms. The yin yang model separate circadian activities in a circadian system into yin (night activities) and yang (day activities) and a circadian clock into a day clock and a night clock. The day clock is the product of night activities, but it promotes day activities; the night clock is the product of day activities, but it promotes night activities. The clock maintains redox or energy homeostasis of the internal environment and allows temporal separations between biological processes with opposite impacts on the internal environment of a circadian system.

Fractal geometry can adequately represent many complex and irregular objects in nature. The fractal dimension is typically computed by the box-counting procedure. Here I compute the box-counting and the Kaplan-Yorke dimensions of the 14-dimensional models of the Drosophila circadian clock. Clockwork Orange (CWO) is transcriptional repressor of direct target genes that appears to play a key role in controlling the dynamics of the clock. The findings identify these models as strange attractors and highlight the complexity of the time-keeping actions of CWO in light-day cycles. These fractals are high-dimensional counterexamples of the Kaplan-Yorke conjecture that uses the spectrum of the Lyapunov exponents.

Examining elevated rates of systemic lupus erythematosus in African-American women from perspectives of immune cognition suggests the disease constitutes an internalized physiological image of external patterns of structured psychosocial stress, a 'pathogenic social hierarchy' involving the synergism of racism and gender discrimination, in the context of policy-driven social disintegration which has particularly affected ethnic minorities in the USA. The disorder represents the punctuated resetting of 'normal' immune self-image to a self-attacking 'excited' state, a process formally analogous to models of punctuated equilibrium in evolutionary theory.

Thus disease onset takes place in the context of a particular immunological 'cognitive module' similar to what has been proposed by evolutionary psychologists for the human mind. Disease progression involves interaction of the hypothalamic-pituitary-adrenal axis, which we also treat as a cognitive physiological submodule, with both immune cognition and an embedding pathogenic social hierarchy, a structured psychosocial stress which literally writes an image of itself on the course of the disorder. Both onset and progression may be stratified by a relation to cyclic physiological responses which are long in comparison with heartbeat period: circadian, hormonal, and annual light/temperature cycles.

The high rate of lupus in African-American women suggests existence of a larger dynamic which entrains powerful as well as subordinate population subgroups, implying that the wide ranging programs of social and economic reform required to cause declines in disease among African-American women will bring significant benefit to all.