Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction o...

Ultraviolet-B radiation acts as an environmental stimulus, but in high doses it has detrimental effects on plant metabolism. Plasma membranes represent a major target for Reactive Oxygen Species (ROS) generated by this harmful radiation. Oxidative reactions occurring in the apoplastic space are counteracted by antioxidative systems mainly involving ascorbate and, to some extent, glutathione. Th...

In this work Eucalyptus grandis and Dipteryx odorata were submitted to photodegradation by ultraviolet radiation. The effect of ultraviolet radiation irradiation on the color change and chemical composition of each wood flour were evaluated. The samples were submitted to a total of 500h of artificial weathering using condensation stages and ultraviolet radiation B irradiation cycles. The change...

Stable high-power operation in the deep ultraviolet is achieved from a multi-kHz diode-pumped multi-longitudinalmode Q-switched Nd:YAG laser by fourth harmonic generation in an external resonant cavity and by fifth harmonic generation using sum-frequency mixing of the fourth harmonic and the residual fundamental in a b-BBO crystal. Over 2.1 W of 266 nm radiation and 540 mW of 213 nm radiation w...

This paper describes experiments on the effects of ultraviolet radiation and of x-rays on the eggs and sperm of the sea urchin Arbacia punclulata, carried out during the summer of 1950.1 These, together with earlier findings already described (Blum and Price, 1950 a, b; Blum, Loos, and Robinson, 1950) permit certain conclusions to be reached regarding the locus of action of these radia-' tions,...

To investigate the characteristics of photosynthetic physiological changes in leaves Mangifera indica L. cv. Guifei under enhanced ultraviolet (UV)-B radiation, natural light-exposed trees were used as controls and 96 kJ·m −2 ·d −1 UV-B radiation was artificially simulated field. The fruit maturity quality, leaf net rate (P n ), pigment contents, photochemical reactions, activities enzymes rela...

The current and projected terrestrial ultraviolet-B (UV-B) radiation affects growth and reproductive potential of many crops. Cowpea (Vigna unguiculata [L.] Walp.), mostly grown in tropical and sub-tropical regions may already be experiencing critical doses of UV-B radiation due to a thinner ozone column in those regions. Better understanding of genotypic variability to UV-B radiation is a prer...

Ultraviolet-B (UV-B) radiation present in sunlight is an important trigger of photomorphogenic acclimation and stress responses in sessile land plants. Although numerous moss species grow in unshaded habitats, our understanding of their UV-B responses is very limited. The genome of the model moss Physcomitrella patens, which grows in sun-exposed open areas, encodes signaling and metabolic compo...

Introduction: Normal exposure to sunlight results in the production of vitamin D in human body, which happens because of the interaction between ultraviolet radiation and cholesterol in skin. Exposure to sunlight is responsible for 90 percent of vitamin D needed for the body. Studies show that Iran is a country with high percentage of lack of vitamin D (83 percent). Based on pr...