Ribonucleotide reductase consists of two nonidentical proteins, R1 and R2, and catalyzes the rate-limiting step in DNA precursor synthesis: the reduction of ribonucleotides to deoxyribonucleotides. A strictly balanced supply of deoxyribonucleotides is essential for both accurate DNA replication and repair. Therefore, ribonucleotide reductase activity is under exquisite control both transcriptio...

Mixed tree–grass vegetation is important globally at ecotones between grasslands and forests. To address uncertainties vis-à-vis productivity and nitrogen (N) cycling in such systems we studied 20 mature oak savanna stands, ranging from 90% woody dominated to 80% herbaceous dominated, growing on comparable soils in a 32-yr-old fire frequency experiment in Minnesota, USA. Fire frequencies ranged...

Since the supremum is taken over a bigger set as B increases, C(B) is nondecreasing for B ≥ 0. To prove the concavity, let B1 and B2 be two cost constraints. Suppose that R1 is achievable under B1 and R2 is achievable under B2 i.e. R1 ≤ C(B1) and R2 ≤ C(B2). Let k = ⌊αn⌋, k ′ = n − k and α ∈ [0, 1]. We can construct a code by using a (21 , k) code for the first k transmissions and a (2 ′R2 , k)...

An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM(-1) s(-1). The enhanced MRI contrast of nanorods is attributed t...

A new approach to parametric localization of a distributed source is proposed. This method is based 071 the ESPRIT Algorithm. the Central angle and the angular extension of an incoherently distributed source are estimated. This algorithm has a low computational complex­ ity. The method does not require array calibration