Perfect Hash Families: The Generalization to Higher Indices

Perfect hash families are often represented as combinatorial arrays encoding partitions of kitems into v classes, so that every t or fewer of the items are completely separated by at least a specified number of chosen partitions. This specified number is the index of the hash family. The case when each t-set must be separated at least once has been extensively researched; they arise in diverse applications, both directly and as fundamental ingredients in a column replacement strategy for a variety of combinatorial arrays. In this paper, construction techniques and algorithmic methods for constructing perfect hash families are surveyed, in order to explore extensions to the situation when each t-set must be separated by more than one partition.https://digitalcommons.usmalibrary.org/books/1029/thumbnail.jp

The spatial structure of lithic landscapes : the late holocene record of east-central Argentina as a case study

Fil: Barrientos, Gustavo. División Antropología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Catella, Luciana. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Oliva, Fernando. Centro Estudios Arqueológicos Regionales. Facultad de Humanidades y Artes. Universidad Nacional de Rosario; Argentin

HEPATO-GASTROENTEROLOGY

Background/Aims: The deleterious effects of intestinal ischemia-reperfusion on liver are realized, but its effect on the regenerative capacity of the liver has not been studied. Our aim in this study was to determine the effect of intestinal ischemia-reperfusion on liver regeneration. Methodology: Sprague-Dawley rats were randomly divided into six groups; two sham-operated, two hepatectomy, and two hepatectomy with intestinal ischemia-reperfusion groups. To create intestinal ischemia-reperfusion, the superior mesenteric artery and collateral arteries supplying the small intestine were occluded for 20 minutes. Partial hepatectomy was performed during the period of ischemia. Ischemia-reperfusion injury in the mucosal layer of the small intestine was scored in light microscopy. Liver regeneration parameters (proliferating cell nuclear antigen labeling index for hepatocytes and liver regeneration rate), and serum levels of aspartate aminotransferase and alanine aminotransferase were studied on day 1 or 4 after operation. Results: Mucosal injury score was high in the hepatectomy with intestinal ischemia-reperfusion groups. Liver regeneration rate and proliferating cell nuclear antigen labeling index were less in these groups than the hepatectomy groups on day 1 and 4. There were no differences in the serum levels of aspartate aminotransferase and alanine aminotransferase between hepatectomy and hepatectomy with intestinal ischemia-reperfusion groups. The mortality rate was higher in the hepatectomy with intestinal ischemia-reperfusion groups than the other groups. Conclusions: Ischemia and reperfusion of the small intestine impaired liver regeneration with high mortality after partial hepatectomy in the rats