-An apparatus providing continuous artificial illumination of constant intensity directed to the lower surface of flounders is pictured. Pigmentation was developed on the lower normally unpigmented surface in a high percentage of summer flounders in the following experimental situations: (1) Unoperated fishes in black tanks illuminated from below. (2) Blinded dark fishes in black tanks illumina...

Time-domain acoustic contrast control method using loudspeaker array has been studied for generating bright and dark zones in personal audio system. Acoustic contrast which is defined as the acoustic energy ratio between bright and dark zones can be inevitably influenced by the uncertainties in the frequency response of loudspeakers. In this paper, a robust extension of broadband acoustic contr...

In dark-grown leaves of Zea mays, the catalase (H2O2:H2O2 oxidoreductase; EC 1.11.1.6; CAT) isozyme CAT-2 is absent. With continuous white light, CAT-2 protein levels increase (due to de novo synthesis) and plateau after 24 hr. When total poly(A)+ RNA (mRNA), polysomes, or isolated polysomal mRNA from light- and dark-treated leaves was translated in vitro, CAT-2 was detected only among the ligh...

The behavior of Tristram's jird (a species of gerbil) in an illuminated open field resembled that of other rodents, comprising round trips to a home base and alternating between periods of progression (locomoting) and of stopping. In this study, we compared the characteristics of exploration in a dark arena with exploration by the same individuals in a lit arena. In the dark arena, stopping epi...

Unicellular, diazotrophic cyanobacteria temporally separate dinitrogen (N2) fixation and photosynthesis to prevent inactivation of the nitrogenase by oxygen. This temporal segregation is regulated by a circadian clock with oscillating activities of N2 fixation in the dark and photosynthesis in the light. On the population level, this separation is not always complete, since the two processes ca...

This communication describes the observation of a new type of dark spontaneousforce optical trap (dark SPOT) obtained without the use of a mask blocking the central part of the repumper laser beam. We observe that loading a magneto-optical trap (MOT) from a continuous and intense flux of slowed atoms and by appropriately tuning the frequency of the repumper laser is possible to achieve basicall...

Daily variations in cGMP, guanylate cyclase and phosphodiesterase activity in golden hamster retina were studied. Cyclic GMP content exhibited significant variations throughout the 24-hr cycle with maximal values during the dark phase. In order to establish the relative participation of nucleotide synthesis and breakdown during a 24-hr cycle, guanylate cyclase and phosphodiesterase activity wer...

An alternating light-dark system is described under which etiolated bean (Phaseolus vulgaris) leaves form selectively chlorophyll a.This system consists of cycles of 2 minutes of white light alternating with 98-minute dark periods.Etiolated tissue exposed to a series of such light-dark cycles accumulates chlorophyll a predominantly, with no lag phase in its biosynthesis. A very high ratio of ch...

A type of photoheterotrophic bacteria contain a transmembrane light-driven proton pump called proteorhodopsins (PRs). Due to the prevalence of these organisms in the upper water column of the World's Ocean, and their potential for light-driven ATP generation, they have been suggested to significantly influence energy and matter flows in the biosphere. To date, evidence for the significance of t...

A sediment-type self-sustained phototrophic microbial fuel cell (MFC) was developed to generate electricity through the synergistic interaction between photosynthetic microorganisms and heterotrophic bacteria. Under illumination, the MFC continuously produced electricity without the external input of exogenous organics or nutrients. The current increased in the dark and decreased with the light...