نتایج جستجو برای: continuous dark
تعداد نتایج: 335312 فیلتر نتایج به سال:
In the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. For this purpose, we used both WMAP9 and Planck data to study how the radius changes with redshift in these mod-els. We used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. The mechanism of structure formation f...
Circadian clocks drive endogenous oscillations in organisms across the tree of life. The Earth's daily light/dark cycle entrains these clocks to the environment. Two major theories of light entrainment have been presented in the literature. The discrete theory emphasizes the instantaneous phase-shifting behavior of short pulses of light, and the continuous theory emphasizes changes to the perio...
OBJECTIVES We aimed to increase the bacterial cell killing efficacy of erythrosine-mediated photodynamic therapy (PDT) of Streptococcus mutans biofilms by fractionating the delivered light dose into a series of shorter pulses. METHODS S. mutans biofilms of 200 microm thickness were grown in a constant-depth film fermenter (CDFF). Biofilms were incubated with 22 microM erythrosine before being...
Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose depe...
3-Hydroxy-3-methylglutaryl (HMG) coenzyme A reductase mRNA accumulates preferentially in dark-grown Arabidopsis plants. As one step toward understanding the role that light plays in the regulation of the mevalonate pathway in plants, we characterized the suppression of HMG1 gene expression in response to illumination wavelength, duration, and fluence rate. The accumulation of HMG1 mRNA by dark ...
The cosmic large-scale structures of the Universe are mainly result gravitational instability initially small density fluctuations in dark-matter distribution. Dark matter appears to be cold and behaves as a continuous collisionless medium on cosmological scales, with evolution governed by Vlasov--Poisson equations. Cold dark can accumulate very efficiently at focused locations, leading highly ...
Brooding corals often exhibit daily planulation peaks in certain phases of lunar months during their reproductive season. The mechanism controlling this diurnal phenomenon, however, remains uncertain. Seriatopora hystrix populations of Southern Taiwan exhibit a highly synchronized planulation rhythm characterized by pre-dawn peak release episodes over a period of 4-6 days per month throughout t...
Abnormal projection of the optic nerves to the wrong cerebral hemisphere transforms the optokinetic system from its usual negative feedback loop to a positive feedback loop with characteristic ocular motor instabilities including directional reversal of the optokinetic nystagmus (OKN) and spontaneous nystagmus, which are common features of infantile nystagmus syndrome (INS). Visual input plays ...
In the prokaryote Synechococcus RF-1, circadian changes in the uptake of l-leucine and 2-amino isobutyric acid were observed. Uptake rates in the light period were higher than in the dark period for cultures entrained by 12/12 hour light/dark cycles. The periodic changes in l-leucine uptake persisted for at least 72 hours into continuous light (L/L). The rhythm had a free-running period of abou...
The ever increasing industrial and consumer applications of titanium dioxide nanoparticles (TiO2 NPs) raise concern over the possible risk associated with their environmental exposure. Still, the knowledge regarding nanoparticle behavior in a freshwater ecosystem is lacking. The current study focuses on the toxicity of TiO2 NPs towards Ceriodaphnia dubia (a dominant daphnid isolated from the fr...
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