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Carnivorous plants indoor lights by using high-luminance, low-spectral-selective irradiance.
Carnivorous plants are exotic ecosystems in which plants consume insects. Their leaves exhibit an array of visual signals that attract insect prey and induce them to enter the leaf-based feeding chamber (henceforth called "carnivorous leaf") where they are fed upon. We showed that in the carnivorous genus Nepenthes, high-luminance, low-spectral-selective ambient light enhances the response of both prey and plant to low-wavelength-selective spectral signals from the prey (optical "attractants"). Here we tested the hypothesis that high-luminance, low-spectral-selective irradiance also affects the response of the carnivorous plant to visual signals, thus modulating the response of the prey. To do so, we quantified the feeding rate and the response to a spectral signal of both insect prey and the carnivorous plant, both in darkness and under a low-spectral-selective green light (with a spectral peak at 514 nm) to obtain a "background" response (in the absence of a potential "target" stimulus). We also measured the response of prey to a high-luminance, low-spectral-selective red light (with a spectral peak at 578 nm) that alone could serve as a potential signal in a natural setting. Results indicated that, regardless of the presence of the plants, prey and plants respond to the green light at the background level. While prey fed on the foliage of carnivorous plants under green light, they did not when fed at the background level. Although plants responded to both green and red light at the background level, the response to the red light was similar to that induced by the green light at background level. These findings support the hypothesis that high-luminance, low-spectral-selective irradiance can modulate the response to a potential visual signal by reducing it and thus the likelihood of a response by the recipient. PMID:25492310
Plants have evolved many mechanisms to monitor their environment. Most of these are passive, which means that they detect the stimulus and respond to it, or active, in which case the response is to a signal which is given and which could then trigger a specific response. Passive mechanisms require the plant to either sense the stimulus or the stimulus to interact with the plant to effect a response. Active mechanisms require the stimulus to be given to the plant, and this gives the plant the possibility to respond to the stimulus with specific responses. These two different mechanisms are not mutually exclusive and will be discussed here. The responses of the plant are based on their perception of the environment, and these responses depend on the amount of light that the plant receives. Light can be sensed as part of a passive mechanism where light triggers a response, or as part of an active mechanism where light triggers a specific response. Light that is perceived as 'noisy' (high-spectral-selective light) will be more likely to be perceived as 'light' (low-spectral-selective light). Light which is perceived as 'quiet' (low-spectral-selective light) will be more likely to be perceived as 'dark'. Both 'noise' and 'quiet' light are given to the plant and are able to interact with the plant. Noise, however, does not allow the plant to actively respond, whereas 'quiet' light does. When the intensity of light becomes too high, the likelihood of a response increases and the plant has to respond in order to protect itself from the damaging effects of the light. PMID:24812707
We study the role of the local character of light quanta emitted by a superconducting fluxonium ring, on the generation of solitons and localized bound states. The fluxonium ring is placed in a strong and homogeneous magnetic field and is driven externally by an inductive current source. We consider the low frequency regime in which the radiation can be treated as a monochromatic wave. A general ansatz for the electric potential is considered, which allows to find the electric field on the surface of the ring. We analyze the interaction of a soliton of the external current source with the ring. As a result of the interaction, the soliton is shifted along the circumference of the ring by a distance proportional to the soliton velocity.
A major challenge in nanoscale optics is the confinement of visible-light and laser energy. Recently, photonic systems based on graphene sheets and their derivative graphene oxide (GO) have been investigated extensively for energy trapping and guiding. These systems are usually fabricated using optical lithography methods, which provide nanoscale resolution and are widely used in nanoelectronics and microelectromechanical systems (MEMS). However, this approach is complicated and requires high-cost facilities and materials, thus preventing it from being used in practical applications. Here, we describe a facile and general fabrication technique to create graphene-based devices based on wet-etching chemical graphene oxide (GO) films. The main steps include the formation of GO on quartz and silicon substrates and the subsequent transfer of GO into target substrates using a standard wet-etching method. The process can be controlled by regulating the thickness of the GO film and the etching duration, which is beneficial for the fabrication of various optical structures. Compared with other etching techniques, this simple method is cost-effective and easy to apply, and it can be used to fabricate a wide range of structures for potential applications. In particular, the etched structure can act as an optical filter or a waveguide for trapping light energy and as a surface for light coupling with plasmonic structures. For example, by adjusting the etching time, we can obtain a GO-based photonic crystal membrane and a GO-based waveguide plate with a subwavelength thickness. Furthermore, the etched structure can be used as a light-trapping layer to enhance the light extraction of LEDs and as a plasmonic nanostructure to enhance the emission efficiency of a LED.