Here, I describe the geographical distribution of the savanna types in Namibia and identify the factors controlling the occurrence of each savanna type in relation to the amount of annual precipitation and the various physiographical regions, including the mopane ( Colophospermum mopane) area. The different types of savanna can be distinguished on the basis of the leaf habits of the dominant ve...

Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation...

These are notes from introductory survey lectures given at the Institute for Studies in Theoretical Physics and Mathematics (IPM), Teheran, in 2008 and 2010. We present the definition and the fundamental properties of Fomin-Zelevinsky’s cluster algebras. Then we introduce quiver representations and show how they can be used to construct cluster variables, which are the canonical generators of c...

Two adult Angora goats were slaughtered each month for 24 consecutive months on a farm in Valley Bushveld in the eastern Cape Province. On the same farm 2 Angora goat kids were slaughtered each month for 2 consecutive years from the time they were 1 week old until they reached 12 months of age. All these goats were processed for the recovery of helminth and arthropod parasites. Fourteen nematod...

Reticulate, or non-bifurcating, evolution is now recognized as an important phenomenon shaping the histories of many organisms. It appears to be particularly common in plants, especially in ferns, which have relatively few barriers to intra- and interspecific hybridization. Reticulate evolutionary patterns have been recognized in many fern groups, though very few have been studied rigorously us...

This study was aimed to document the floristic attributes of pteridophytes District Tor Ghar; Khyber Pakhtunkhwa, Pakistan. Total 41 species distributed in 20 genera and 10 families were recognized. Dryopteridaceae largest family with 12 (29.26%). Second third large is Pteridaceae Thelypteridaceae (24.39%) 5 (12.19%) respectively. Like-wise, Dryopteris genus 6 (14.63%) species. The main Aspleni...