نتایج جستجو برای: light intensity

تعداد نتایج: 558624  

Journal: :Plant physiology 1971
J M Pickett

The separate package and spillover models of photosynthetic enhancement are generalized and extended to light saturation assuming hyperbolic or exponential rate versus intensity curves. The available data are more consistent with the exponential model at high light intensities. Two significant conclusions follow: (a) the decreases in enhancement observed at high light intensities are accounted ...

Journal: :Optics letters 2000
K Clays S Van Elshocht A Persoons

The angular dependence of the hyper-Rayleigh scattered light intensity from a suspension of bacteriorhodopsin has been analyzed. The observation calls for combination of the second-order nonlinear hyperpolarizability of the retinal chromophore with the linear refractive index of the apo-protein matrix. The structuring of the small nonlinear chromophore in the large linear matrix imparts propert...

Journal: :Journal of the Royal Society, Interface 2012
L Lahuerta Zamora M T Pérez-Gracia

The McFarland method allows the concentration of bacterial cells in a liquid medium to be determined by either of two instrumental techniques: turbidimetry or nephelometry. The microbes act by absorbing and scattering incident light, so the absorbance (turbidimetry) or light intensity (nephelometry) measured is directly proportional to their concentration in the medium. In this work, we develop...

2014
Quamrul Ashraf Oded Galor Marc Klemp

This research establishes that migratory distance from the cradle of anatomically modern humans in East Africa and its effect on the distribution of genetic diversity across countries has a hump-shaped effect on nighttime light intensity per capita as observed by satellites, reflecting the trade-off between the beneficial and the detrimental effects of diversity on productivity. The finding len...

2001
Daniel Macdonald Ronald A. Sinton Andrés Cuevas

The effectiveness of a method for analytically reducing the effect of trapping centers on photoconductance-based recombination lifetime measurements in silicon is examined. The correction method involves the use of a ‘‘bias-light’’ term to subtract out the underlying photoconductance due to the traps. The technique extends, by approximately an order of magnitude, the range of carrier densities ...

Journal: :Optics express 2010
Jan Renger Muamer Kadic Guillaume Dupont Srdjan S Aćimović Sébastien Guenneau Romain Quidant Stefan Enoch

One of the key challenges in current research into electromagnetic cloaking is to achieve invisibility at optical frequencies and over an extended bandwidth. There has been significant progress towards this using the idea of cloaking by sweeping under the carpet of Li and Pendry. Here, we show that we can harness surface plasmon polaritons at a metal surface structured with a dielectric materia...

Journal: :Applied and environmental microbiology 2004
Matthew J Church Hugh W Ducklow David M Karl

The influence of irradiance on bacterial incorporation of [(3)H]leucine was evaluated at Station ALOHA in the oligotrophic North Pacific subtropical gyre. Six experiments were conducted on three cruises to Station ALOHA to examine how [(3)H]leucine incorporation varied as a function of irradiance. Two experiments were also conducted to assess the photoautotrophic response to irradiance (based o...

Journal: :Optics express 2006
B Lacaze M Chabert

Recent laser technology provides accurate measures of the dynamics of fluids and embedded particles. For instance, the laser-extinction measurements (LEM) uses a laser beam passing across the fluid and measures the residual laser light intensity at the fluid output. The particle concentration is estimated from this measurement. However, the particle flow is submitted to random time-varying fluc...

Amit Jena Govind Shashirekha Satyajit Mohapatra

Aim: The purpose of this study was to compare the difference in the output intensity of Light Emitting Diode (LED) light cure (LC) devices with and without a protective sleeve and its clinical significance.  Materials and Methods: The output intensity of 152 LC units in dental offices across the state of Odisha were examined. The collection of related information included an average number of e...

Phytoene synthase (Psy) and Phytoene desaturase (Pds) are the first two regulatory enzymes in the carotenoids biosynthetic pathway. The genes Psy and Pds are under transcriptional control in many photosynthetic organisms. In the present study, using quantitative real time- PCR (qRT-PCR), the effects of uncoated and gum-Arabic coated PbS nanoparticles (GA-coated PbS NPs) and light intensity on t...

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