A new dosimetric package for assessing solar radiation affecting photosynthesis in the visible and ultraviolet wavebands in plant canopies has been developed and tested. The package consists of several detectors sensitive to various wavebands between 290 and 700 nm. For photosynthetically active radiation (PAR), the dosimeter was calibrated for exposures in terms of photosynthetically active ph...

Epidemiological studies suggest a relationship between suntanning habits and high risk of melanoma. A literature review was carried out for the period between 1977 and 1998 using Medline and Embase (Excerpta Medica) databases. The analysis showed that intentional sun exposure is highly prevalent among youths, despite their awareness of the risks involved in excessive exposure to ultraviolet rad...

in order to study of the radiation interception and red to far red light ratio variations in sunflower hybrids under drought stress, nine sunflower hybrids in three separate experiments were compared as randomized complete block designs with three replications at the research station of seed and plant improvement institute in karaj in 2006. first experiment (control) was irrigated based on 60 m...

BACKGROUND Describing vitamin D status and its predictors in various populations is important in order to target public health measures. OBJECTIVES To describe the status and predictors of vitamin D status in healthy Nepalese mothers and infants. METHODS 500 randomly selected Nepalese mother and infant pairs were included in a cross-sectional study. Plasma 25(OH)D concentrations were measur...

Vitamin D signaling plays a key role in various important processes, including cellular proliferation, differentiation, and apoptosis, immune regulation, hormone secretion, and skeletal health. Further, vitamin D production and supplementation have been shown to exert protective effects via an unknown signaling mechanism involving the vitamin D receptor (VDR) in several diseases and cancer type...

There is a growing interest for vitamin D in the medical and scientific community as well as in the public medias as illustrated by a huge number of publications. Most experts claim that vitamin D deficiency/insufficiency is widespread with potential important public health consequences. It may seem surprising for many persons that a deficiency in a vitamin may be so frequent in countries where...

Iran has great potential in utilizing solar energy. In order to maximize the amount of absorbed solar radiation to absorber surfaces, the surfaces should be installed at a suitable angle slope to the horizon that is discussed in this article. The calculations performed in this study was done using MATLAB software. In this study, radiation received on the ground in 31 provincial capitals of the ...

The correlation between decreased morbidity and mortality of cancer and exposure to sunlight is known. The many biological functions of vitamin D that contribute to cancer prevention have only recently begun to be appreciated. Once activated 1,25-dihydroxyvitamin D [1,25(OH)2D3] functions as a potent inhibitor of normal and cancer cellular proliferation. Vitamin D deficiency in mice led to a 60...

An influence of solar irradiance variations on Earth’s surface climate has been repeatedly suggested, based on correlations between solar variability and meteorological variables1. Specifically, weaker westerly winds have been observed in winters with a less active sun, for example at the minimum phase of the 11-year sunspot cycle2–4. With some possible exceptions5,6, it has proved difficult fo...

S urface solar radiation is a major component of the surface heat budget. Diurnally and seasonally averaged over the entire Earth, 188 ± 7 W m–2 reach the surface to be either absorbed (~165 ± 6 W m–2) or reflected back to the atmosphere (Trenberth et al. 2009; Stephens et al. 2012). Changes in the amount of solar radiation received at the surface are intrinsically tied to the total amount of p...