abstract in order to study the effect of environmental factors (light, temperature, salinity and drought stress, acidity and burial depth) on germination and emergence of eastern dodder (cuscuta monogyna vahl), experiments were conducted at the research laboratory of faculty of agriculture, birjand university in 2009. results showed that seeds of this parasite weed had identical germination und...

This study investigated the growth rate, proximate composition, and fatty acid profile in juvenile of kutum Rutilus frisii kutum in different dark-light cycles. Fish were stocked randomly in eighteen 2000-L fiberglass tanks and received six photoperiod regimes: natural photoperiod, 24L (light):0D (day), 16L:8D, 12L:12D, 8L:16D and 0L:24D. Application of continuous dark (0L:24D) and an intermedi...

Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium which demonstrated extensive metabolic periodicities of photosynthesis, respiration, and nitrogen fixation when grown under N2-fixing conditions. N2 fixation and respiration peaked at 24-h intervals early in the dark or subjective-dark period, whereas photosynthesis was approximately 12 h out of phase and peaked towa...

This study evaluated the effect of the intermittent light program on serum and brain melatonin concentrations, antioxidant enzyme activities, and homocysteine concentration in broiler chickens. A total of 60 one-day-old broiler chickens (Cobb 500) were distributed in three light-proof controlled rooms (20 chicks per room). All birds were reared in continuous light until 3 days of age. Then, chi...

A comparison of electroretinogram (ERG) thresholds measured on rats reared in continuous darkness and under cyclic lighting conditions shows that by 30 days of age the dark-reared animals have achieved significantly lower thresholds than the animals reared under cyclic illumination. Ten days of continuous dark exposure produces this same increase in sensitivity in adult rats reared in cyclic li...

Germination of nine important medicinal plant species from the high altitudes of southern Africa was investigated in relation to different environmental parameters. The seeds were subjected to different constant and alternating temperatures, temperature shifts, light and dark conditions, and cold stratification periods. Temperature regimes of 17–23°C appear most suitable for optimal germination...

The present study concerns the search for ageing effects in 0.3mm gap timing RPCs. Counters were made with glass and aluminium electrodes and kept under a continuous gas flow of tetrafluorethane with 10% sulphur hexafluoride, 5% isobutane and water at 10% relative humidity. After 500 days of operation at the saturation current an accumulated charge of 800mC was collected, equivalent to over 8 y...

EDELWEISS is a direct search for WIMP dark matter using cryogenic heat-and-ionization germanium detectors. We report the final results of the second stage of the experiment, EDELWEISS-II, obtained with an array of ten 400 g detectors. A total effective exposure of 384 kg.day has been achieved, obtained following fourteen months of continuous operation at the Laboratoire Souterrain de Modane. Fi...