نتایج جستجو برای: ultraviolet b radiation
تعداد نتایج: 1143956 فیلتر نتایج به سال:
For the embryos and tadpoles of amphibian species, exposure to ultraviolet-B radiation (UVBR) can be lethal, or cause a variety of sublethal effects. Low temperatures enhance the detrimental effects of UVBR and this is most likely because the enzyme-mediated processes involved in the repair of UVBR-induced damage function less effectively at low temperatures. Whether these repair processes are ...
We measured chlorophyll (chl) concentration and chl a/b ratio in Sphagnum balticum, S. jensenii, and S. lindbergii, sampled after 7 and 8 years of ultraviolet-B (UVB) and temperature manipulation in an open field experiment in Finnish Lapland (68°N). We used plastic filters with different transmittance of UVB radiation to manipulate the environmental conditions. The plants were exposed to (1) a...
Many spider orb-webs are exposed to sunlight and the potentially damaging effects of ultraviolet B (UVB) radiation. We examined the effect of UVB on the viscoelastic glycoprotein core of glue droplets deposited on the prey capture threads of these webs, hypothesizing that webs built by species that occupy sunny habitats are less susceptible to UVB damage than are webs built by species that pref...
Most studies on ecological impact of solar ultraviolet (UV) radiation generally focus on plants. However, UV radiation can also affect organisms at other trophic levels. Protection against mortality induced by solar UV has, therefore, been hypothesized as one of the reasons why Typhlodromalus aripo hides in the apex of cassava plants during the day and comes out at night to prey on spider mites...
Climate change and water extraction may result in increased exposition of the biota to ultraviolet-B radiation (UVB) in high-altitude Andean lakes. Although exposition to lethal doses in these lakes is unlikely, sub-lethal UVB doses may have strong impacts in key compartments such as zooplankton. Here, we aimed at determining the effect of sub-lethal UVB doses on filtration rates of two cladoce...
In studying the ultraviolet (UV) radiation, one of the important factors is the possibility of generating a variety of free radicals inside the body by these radiations. In this paper, a method of estimating the amount of hydroxyl radicals produced by ultraviolet rays was investigated using nanoparticles of tin oxide doped with uropium. In this method, the change in absorption intensity of meth...
The variation characteristics of Ultraviolet-B (UVB; 280-315 nm) radiation over Beijing were explored using measured data that were collected in Beijing from November 2010 to October 2011. Seasonal variations in UVB radiation and influence of ozone and clearness index on the ratio of UVB to broadband solar radiation (G) were investigated. The annual value of UVB radiation in Beijing is 6.37 MJ ...
The solar ultraviolet radiation (UVR) exposure of 30 children and adolescents in three age groups (4-6 years, 7-9 years and 13-14 years) was measured for 1 week in late summer (February-March) in Durban, South Africa, using UVR-sensitive polysulfone film badges (PSFB) attached to the lapel region of the body. The mean and median values for all ages over the study period were 2.0 and 1.2 standar...
Ultraviolet-B radiation (UVB) reaching the earth's surface has increased due to human-caused stratospheric ozone depletion. Whereas the harmful effects of UVB on aquatic organisms are well studied at the molecular and cellular level, recent studies have also begun to address behavioural changes caused by sublethal amounts of UVB. However, the behavioural consequences of long-term exposure to ec...
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