Inspired by classical work of Bel and Robinson, a natural purely algebraic construction of super-energy (s-e) tensors for arbitrary fields is presented, having good mathematical and physical properties. Remarkably, there appear quantities with mathematical characteristics of energy densities satisfying the dominant property, which provides s-e estimates useful for global results and helpful in ...

Convex polygonal lines with vertices in Z+2 and endpoints at 0=(0,0) n=(n1,n2)→∞, such that n2/n1→c∈(0,∞), under the scaling n1−1, have limit shape γ* respect to uniform distribution, identified as parabola arc c(1−x1)+x2=c. This is universal a large class of so-called multiplicative ensembles random lines. The present paper concerns inverse problem shape. In contrast aforementioned universalit...

The hemoglobin receptor IsdB rapidly acquires heme from methemoglobin (metHb) in the heme acquisition pathway of Staphylococcus aureus. IsdB consists of N-terminal segment (NS), NEAT1 (N1), middle (MD), and heme binding NEAT2 (N2) domains, and C-terminal segment (CS). This study aims to elucidate the roles of these domains or segments in the metHb/IsdB reaction. Deletion of CS does not alter th...

A famous unsolved conjecture of P. Erdős and J. L. Selfridge states that there does not exist a covering system {as(mod ns)}s=1 with the moduli n1, . . . , nk odd, distinct and greater than one. In this paper we show that if such a covering system {as(mod ns)}s=1 exists with n1, . . . , nk all square-free, then the least common multiple of n1, . . . , nk has at least 22 prime divisors.

The macro acidity constants valid for aqueous solutions of several adenine, guanine, and hypoxanthine derivatives are summarized. It is shown how the application of the corresponding constants, e.g., for 7,9-dimethyladenine, allows a quantification of the intrinsic acidic properties of the (N1)H0/+ and (N7)H+ sites via micro acidity constants, and how to use this information for the calculation...