The present study was focused to examine the combined effects of climate and ultraviolet-B radiation on conifer tree-ring density. Statistical methods were employed to extract tree responses in annual ring density and to identify functional relationship in trees when the level of ultraviolet-B radiation changes regardless of climate variations. In this study, the consideration was given to the ...

Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have demonstrated that males calling from high perches are...

basil plants (ocimum basilicum l.) were sprayed with salicylic acid (1mm) and exposed to ultraviolet-c (uv-c) radiation (40 wm-2) after emergence of six developed leaves. plants were grown for 18 days and exposed to uv-c for 5 mind-1 alternatively. chlorophyll a, chlorophyll b and carotenoide were considered for analysis of photosynthetic pigments. the results showed that the photosynthetic pig...

ultraviolet waves, because of their short wavelength, have a high energy and considerable damaging effects on surfaces. protection against ultraviolet radiations is one of the finishing treatments done on surfaces exposed to sunlight. the importance of this issue in relation to human health, due to complications such as skin burns and cancer, is doubled. up to now, different materials such as z...

The ultraviolet radiation present in sunlight is the primary cause of nonmelanoma skin cancer and has been implicated in the development of cutaneous malignant melanoma. In addition, ultraviolet is immune suppressive and the suppression induced by ultraviolet radiation has been identified as a risk factor for skin cancer induction. Ultraviolet also suppresses the immune response to infectious a...

Various experiments are described which show the locus of action of ultraviolet radiation and of x-ray in delaying cell division of the fertilized egg of Arbacia punctulata to be in the nucleus. Photorecovery following ultraviolet radiation has its locus in the egg cytoplasm. Analogy is drawn with the action of ultraviolet radiation and photorecovery on the E. coli-bacteriophage system, and cer...

Pterygium is thought to be hyperaemia of fibrovascular tissue on to the cornea caused by ultraviolet radiation of sunlight. We observed a significantly high incidence of pterygia in welders who were exposed occupationally to excess ultraviolet radiation and found a close relationship between the incidence and the length of employment as a welder (r = 0.975, p less than 0.05). This study attempt...

physical agents such as ultraviolet or ionizing radiation and repetitive trauma have been related to the causation of cancer in humans. much less clear is the association between exposure to radiofrequency, such as radar and microwave radiation to the development of cancer. sporadic case reports and small series suggest that this type of radiation might lead to cancer or contribute to its evolu...