mndo semi-empirical scf mo calculations are used to study the pyramidal nitrogen atom inversion and configurational equilibria in the title compounds.

a 2-years (2007-2009) field study was carried out at the college of agriculture, shiraz university, to evaluate the influence of crop residues management and nitrogen (n) rates on soil quality and barley grain protein under dryland conditions. the experiment was conducted as strip split plot with four replications. horizontal plots were three crop residues rates (0, 750 and 1500 kg ha-1), verti...

In this article we introduce the notion of n-capable groups. It is shown that every group G admits a uniquely determined subgroup (〖Z^n)〗^* (G) which is a characteristic subgroup and lies in the n-centre subgroup of the group G. This is the smallest subgroup of G whose factor group is n-capable. Moreover, some properties of n-central extension will be studied.

Poorly drained claypan soils can increase the importance of tillage and N management for corn (Zea mays L.) production. Field research in 2008, 2009 and 2010 (high rainfall years) near Novelty, MO (40° 1' N, 92° 11' W) sought to determine the effect of polymer-coated urea (PCU) placement [strip-tillage (ST) deep banded and no-till (NT) broadcast] and application timing (fall, early preplant...

the aim of this study was to evaluate the effect of different potassium (k) and nitrogen (n) concentrations in nutrient solution and their interaction on growth and quality of tomato transplants. a full factorial experimental design was carried out with three potassium concentrations (1.5, 3 and 6 meql-1) and three nitrogen concentrations (1.5, 3 and 6 meql-1) for 27 days after seed germination...

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Arterial elasticity is determined by structural characteristics of the artery wall and by vascular smooth muscle tone. The identity of endogenous vasoactive substances that regulate elasticity has not been defined in humans. We hypothesized that NO, a vasodilator released constitutively by the endothelium, augments arterial elasticity. Seven healthy young men were studied. A 20-MHz intravascula...