Apparent Horizons with Nontrivial Topology and the Hyperhoop Conjecture in Six-Dimensional Space-Times

We investigate the validity of the hyperhoop conjecture, which claims to determine a necessary and sufficient condition for the formation of black hole horizons in higher-dimensional space-times. Here we consider momentarily static, conformally flat initial data sets each describing a gravitational field of uniform massive k-sphere sources, for k=1,2, on the five-dimensional Cauchy surface. The numerical result shows the validity of the hyperhoop conjecture for a wide range of model parameters. We also confirm for the first time the existence of an apparent horizon homeomorphism to S**2 x S**2 or S**1 x S**3, which is a higher-dimensional generalization of the black ring.Comment: 17 pages, 12 figures. to appear in Phys. Rev.

Investigation of laparoscopic therapy in 56 cases of duodenal ulcer perforation

Background: Although conservative therapy has been acceptable as the first-line therapy for duodenal ulcer (DU) perforations, surgical therapies are known to have certain advantages. We investigated the indications for laparoscopic (LS) or open surgery (OS) or conservative therapy (CoT) among 56 DU perforation cases over 5 years. Methods: 31 LSs, 22 OSs and 5 CoTs were analyzed for patient's physical and surgical factors and clinical course. Results: Mean age was 51.6. Male/female ratio was 49/9. Survival ratio was 98%. Although the hospital stay (10.9 vs 19.5 days) and analgesic administrations (1.9 vs 4.6 days) were significantly shorter in LS than OS, almost all OS patients were in serious condition as evidenced by longer waiting time before treatment, stronger pain, bigger hole of perforation, more ascites accumulation and higher morbidity of complications. Two cases of multisurgery were experienced in both LS and OS groups due to leakage of seam, abscess formation, relapsed ulcer or idiopathic intestinal perforation. LS is a therapy more widely usable and more beneficial than the other two. Conclusion: LS, a minimally invasive surgery for DU perforation, should be considered as a first-line standard therapy because of significant advantages such as shorter hospital stay. OS or CoT may be selected when appropriate

(2,7-Dimeth­oxy­naphthalen-1-yl)(3-nitro­phen­yl)methanone

The title compound, C19H15NO5, has an intra­molecular C—H⋯O=C hydrogen bond between a naphthalene H atom and the O atom of the carbonyl group. The inter­planar angle between the naphthalene ring system and the benzene ring is 69.59 (5)°. The dihedral angle between the bridging carbonyl C—C(=O)—C plane and the naphthalene ring system is 61.02 (6)°, which is far larger than that between the bridging carbonyl plane and the benzene ring [12.68 (7)°]. The nitro group is slightly out of the plane of the benzene ring [O—N—C—C torsion angle = 4.97 (17)°]. In the crystal, the packing is mainly stabilized by C—H⋯O inter­actions between an H atom of the benzene ring and an O atom of the nitro group

1,8-Bis(4-amino­benzo­yl)-2,7-dimeth­oxy­naphthalene

The title compound {systematic name: [8-(4-aminobenzoyl)-2,7-dimethoxynaphthalen-1-yl](4-aminophenyl)methanone}, C26H22O4N2, possesses crystallographically imposed twofold symmetry, with two C atoms lying on the rotation axis. In the crystal, the mol­ecules inter­act through inter­molecular N—H⋯O hydrogen bonds between the amino and meth­oxy groups on the naphthalene ring systems and N—H⋯π inter­actions between the amino groups and the naphthalene rings. Furthermore, weak C—H⋯O hydrogen bonds and π–π stacking inter­actions between the benzene rings are observed. The centroid–centroid and inter­planar distances between the benzene rings of the aroyl group and the naphthalene ring systems of adjacent mol­ecules are 3.6954 (8) and 3.2375 (5) Å, respectively. The dihedral angle between the mean planes of the benzene ring and the naphthalene ring system is 83.59 (5)°. The benzene ring and the carbonyl group in the benzoyl unit are almost coplanar [C—C—C—O torsion angle = 175.91 (10)°]

Experiment Study on Incipient Floating Condition and Directional Stability of Car during Flood

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive