![]() As the summer wore on and the drought in our area got worse (and I got too tired to water all my gardens in the same day) the Arctotis just got prettier. The DNA damage caused indirectly to skin by UVA consists mostly of single-strand breaks in DNA, while the damage caused by UVB includes direct formation of thymine dimers or cytosine dimers and double-strand DNA breakage. Native to South Africa, African Daisies (Arctotis) are showy tender perennials exhibiting brightly colored daisy-like flowers, up to 3 in. Humans need some UV radiation to maintain adequate vitaminD levels. wide (8 cm), contrasting with their black or yellow center disks and their beautiful, finely cut, silvery-green foliage. It can also be used in fluorescent lamps, which are a more energy-efficient form of artificial lighting compared with incandescent lamps. These symptoms are caused by temporary damage to the cells on the surface of the eye. ![]() Vitamin D can also be obtained from food and supplementation. Native to South Africa, Arctotis x hybrida 'Flame' is a stunning African Daisy exhibiting large, 4 in. This plant is said to grow outdoors in the following regions: On Mar 12, 2013, camrichdesigns from Scottsdale, AZ wrote: Planted two of these last Spring, and they flowered beautifully until the Summer heat arrived. Crystalline quartz and some crystals such as CaF2 and MgF2 transmit well down to 150nm or 160nm wavelengths. Its maximum UV transmission is at 365nm, one of the wavelengths of mercury lamps. UV radiation is useful in preparing low-surface-energy polymers for adhesives. In using only common names, however, confusion among gardeners can feel frustrating. Depending on its wavelength, it can get through the ozone layer and affect our health in different ways. ", "Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals", "UVC LEDs Enhance Chromatography Applications", "UV laser diode: 375nm center wavelength", A simple, reliable ultraviolet laser: The Ce:LiSAF, "Broadly tunable difference-frequency generation of VUV using two-photon resonances in H, "Quantum-state-selected integral cross sections for the charge transfer collision of, "The benefits and risks of ultraviolet tanning and its alternatives: The role of prudent sun exposure", The known health effects of UV: Ultraviolet radiation and the INTERSUN Programme, "How to increase serotonin in the human brain without drugs", "Beneficial effects of UV radiation other than via vitaminD production", "Health effects of ultraviolet radiation", "Excimer laser therapy and narrowband ultravioletB therapy for exfoliative cheilitis", "Mutations of the BRAF gene in human cancer", "Shunning the sun may be killing you in more ways than you think", "DNA damage after acute exposure of mice skin to physiological doses of UVB and UVA light", 10.1562/0031-8655(2001)0732.0.CO 2, "Skin penetration and sun protection factor of five UV filters: Effect of the vehicle", "Could sunscreens increase melanoma risk? Upright on 5 stems, they show nicely against the well-behaved 1 x 3 compact mound of fuzzy, silvery foliage. Atomic emission spectra were more proof of the quantized nature of light and led to a new model of the atom based on quantum theory.Articles from Britannica Encyclopedias for elementary and high school students. White light viewed through a prism and a rainbow are examples of continuous spectra. This would result in what is known as a continuous spectrum, where all wavelengths and frequencies are represented. ![]() Likewise, when the atoms relaxed back to a lower energy state, any amount of energy could be released. According to classical physics, a ground state atom would be able to absorb any amount of energy rather than only discrete amounts. (Credit: Christopher Auyeung, using emission spectra available in the public domain Source: CK-12 Foundation H spectrum: Commons Wikimedia, Emission Spectrum- H(opens in new window) visible spectrum: Commons Wikimedia, Linear Visible Spectrum (opens in new window) He spectrum: Commons Wikimedia, Helium Emission Spectrum(opens in new window) Fe spectrum: Commons Wikimedia, Emission Spectrum-Fe(opens in new window) License: CC BY-NC 3.0(opens in new window))Ĭlassical theory was unable to explain the existence of atomic emission spectra, also known as line-emission spectra. ![]()
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