weather circulation patterns play a main role in the occurrence of environmental phenomena especially in middle latitude. occurrence of dry and wet spells is in relation to synoptical system repetitions and types of weather. in this research first by using of standard precipitation index (spi), extensive droughts in the province were identified. then by using principal component analysis (pca) ...

today, chronic viral hepatitis is considered as a public health problem in the world. totally, 5% of the world population, especially in asia and africa suffer from this problem. the prevalence of acute hepatitis in america is 0.1-0.2 percent, 50% of those with hepatitis c (hcv) and 5-10% of them with hepatitis b (hcv) develop chronic hepatitis. determining hbv and hcv genotypes is important to...