Subsuns, Bottlinger's rings, and elliptical halos are simulated by the use of a Monte Carlo model; reflection of sunlight from almost horizontal ice crystals is assumed. Subsuns are circular or elliptical spots seen at the specular reflection point when one flies over cirrus or cirrostratus clouds. Bottlinger's rings are rare, almost elliptical rings centered about the subsun. Elliptical halos ...

‎Let $I$ be an ideal in a regular local ring $(R,n)$‎, ‎we will find‎ ‎bounds on the first and the last Betti numbers of‎ ‎$(A,m)=(R/I,n/I)$‎. ‎if $A$ is an Artinian ring of the embedding‎ ‎codimension $h$‎, ‎$I$ has the initial degree $t$ and $mu(m^t)=1$‎, ‎we call $A$ a {it $t-$extended stretched local ring}‎. ‎This class of‎ ‎local rings is a natural generalization of the class of stretched ...

artemisia species, growing in almost all the northern hemisphere, is used in folk medicine of some countries as a remedy for hypertension. since some cardiovascular disorders including hypertension are accompanied with altered responsiveness of vascular alpha-adrenergic receptors, the effect of aqueous artemisia annua extract (100 and 200 mg kg-1) on a1-adrenoceptor agonist-induced contraction ...

The asymmetric unit of the title compound, C(18)H(18)N(2)O(3), contains two mol-ecules. The fused rings of both mol-ecules are almost planar, with dihedral angles of 3.1 (1) and 2.8 (2)° between the fused rings. The furan rings are rotated by 43.85 (15) and -21.07 (9)° with respect to the planes of the attached bnzimidazole systems. In the crystal, mol-ecules are linked into infinite chains by ...

Strong flatness properties are established for a large class of functional-analytic rings including all C*-algebras. This is later used to prove that all those rings satisfy excision in Hochschild and in cyclic homology over almost arbitrary rings of coefficients and that, for stable C*-algebras, the Hochschild and cyclic homology groups defined over an arbitrary coefficient ring k subset C of ...

• Vectorspaces over division rings • Matrices, opposite rings • Semi-simple modules and rings • Semi-simple algebras • Reduced trace and norm • Other criteria for simplicity • Involutions • Brauer group of a field • Tensor products of fields • Crossed product construction of simple algebras • Cyclic algebra construction of simple algebras • Quaternion algebras • Examples • Unramified extensions...

In the title compound, C(16)H(18)N(2)O(2), the mol-ecule adopts an E conformation about the C=N double bond. The dihedral angle between the pyrrole and phenyl rings is 41.55 (8)°. In the crystal structure, pairs of inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers. In the dimer, the two pyrrole rings are almost coplanar and the two phenyl rings are parallel to...

The structure of the title compound, C(23)H(18)N(2)S, is revealed by X-ray diffraction to be almost planar over all four aromatic rings; the pendant rings are at angles of 10.18, 14.12 and 15.42° relative to the central pyridine ring for the 4-methylsulfanyl, 2-pyridyl and 6-phenyl rings, respectively. The 2,6-aromatic substituents are disordered over two sites in a 0.6:0.4 occupancy ratio.

The cation of the salt, C(18)H(18)N(2)O(2) (2+)·2NO(3) (-), lies about a twofold rotation axis. The pyridinium ring is almost coplanar with the phenyl-ene ring [dihedral angle between rings = 5.69 (9)°]. The crystal structure shows π-π stacking inter-actions [centroid-centroid distance = 3.70 (1) Å] between the pyridinium rings and the phenyl-ene rings, generating a linear chain structure. The ...