104,404 research outputs found
Abelian 1-factorizations in infinite graphs
No full textFor each finitely generated abelian group G, we construct a 1-factorization of the countable complete graph admitting G as an automorphism group acting sharply transitively on vertices
Edge-colorings of 4-regular graphs with the minimum number of palettes
No full textA proper edge-coloring of a graph G is an assignment of colors to the edges of G such that adjacent edges receive distinct
colors. A proper edge-coloring defines at each vertex the set of colors of its incident edges. Following the terminology introduced by Horňák, Kalinowski, Meszka and Woźniak, we call such a set of colors the palette of the vertex. What is the minimum number of distinct palettes taken over all proper edge-colorings of G? A complete answer is known for complete graphs and cubic graphs. We study in some detail the problem for 4-regular graphs
A new description of perfecly one-factorable cubic graphs
No full textA perfectly one-factorable (P1F) regular graph is a graph admitting a partition of the edge-set into one-factors such that the union of any two of them is a Hamiltonian cycle. The case of cubic graphs is treated. The existence of a P1F cubic graph is guaranteed for each admissible value of the number of vertices. A description of this class was obtained by Kotzigin 1962. It is the purpose of the present paper to produce an alternative proof of Kotzig's result
S.E.M. study II. Protective effect of ranitidine against gastric and duodenal lesions induced by non-steroidal anti-inflammatory drugs
No full textThe effect of Ranitidine on the gastric and duodenal lesions induced by Aspirin or Piroxicam was studied by scanning electron microscopy (SEM). Twelve patients were entered into the study. The first group consisted of 6 patients with normal basic morphology, of which 3 were treated with 1.5 g of Aspirin and Ranitidine 300 mg/day, and 3 with 20 mg of Piroxicam and Ranitidine 300 mg/day, for one month. The second group was composed of 6 rheumatic patients, 3 of which took 1.5 g of Aspirin and the other 3 received 20 mg of Piroxicam per day for at least four months. Ranitidine (300 mg/day) was then administered concomitantly for one month to all these 6 patients. Overall, Ranitidine appeared to have a positive effect in preventing the development of gastroduodenal lesions induced by these anti-inflammatory drugs in the first group of patients. No differences were observed in the ability of Ranitidine to promote the healing of lesions induced by chronic treatment. Ranitidine, however, appeared to be more effective in preventing lesions induced by Aspirin rather than those induced by Piroxicam
Frattini-based starters in 2-groups
No full textLet G be a group of order 2^t , with t >3. We prove a sufficient condition for the existence of a one-factorization of a completegraph, admitting G as an automorphism group acting sharply transitively on the vertex-set
Perfect one-factorizations in generalized Petersen graphs
No full textA perfectly one-factorable (P1F) regular graph G is a graph admitting a partition of the edge-set into one-factors such that the union of any two of them is a Hamiltonian cycle. We consider cubic graphs. The existence of a P1F cubic graph is guaranteed for each admissible value of the number of vertices. We give conditions for determining P1F graphs within a subfamily of generalized Petersen graphs
- …
