altGrad		Calculates the altitudinal gradient of budburst
noMix           Determines the number of underlying mixed distritutions
combinations    Calculates all possible combinations of a vector of integers
equaly          Determines and extracts years where both observations stations recorded budburst
bise            Extracts true NDVI values out of noisy data
minimum         Extracts of the true NDVI values out of noisy data the minimum
maximum         Extracts of the true NDVI values out of noisy data the maximum