111,994 research outputs found
Joining caterpillars and stability of the tree center
No full textAbstractThe path-table P(T) of a tree T collects information regarding the paths in T: for each vertex v, the row of P(T) relative to v lists the number of paths containing v of the various lengths. We call this row the path-row of v in T.Two trees having the same path-table (up to reordering the rows) are called path-congruent (or path-isomorphic).Motivated by Kelly–Ulam's Reconstruction Conjecture and its variants, we have looked for new necessary and sufficient conditions for isomorphisms between two trees.Path-congruent trees need not be isomorphic, although they are similar in some respects. In [P. Dulio, V. Pannone, Trees with path-stable center, Ars Combinatoria, LXXX (2006) 153–175] we have introduced the concepts of trunk Tr(T) of a tree T and ramification ramv of a vertex v∈V(Tr(T)), and proved that, if the ramification of the central vertices attains its minimum or maximum value, then the path-row of a central vertex is “unique”, i.e. it is different from the path-row of any non-central vertex (in fact, this uniqueness property of a central path-row holds for all trees of diameter less than 8, regardless of the ramification values).In this paper we prove that, for all other values of the ramification, and for all diameters greater than 7, there are trees in which the above uniqueness fails
The converse of Kelly’s lemma and control-classes in graph reconstruction
No full textsummary:We prove a converse of the well-known Kelly’s Lemma. This motivates the introduction of the general notions of -table, -congruence and control-class
Trees with the same path-table
No full textAs a generalization of isomorphisms of graphs, we consider path-congruences, that is maps which preserve the number of paths of any length.We construct families of pairs of non-isomorphic trees with the same path-table.<br /
38th Annual meeting of the European Society for Pediatric Gastroenterology hepatology and Nutrition. Porto, Portugal, June 1-4, 2005. Osteoporosis and inflammatory bowel disease (IBD) in children: Variables affecting bone mineral density (BMD). M. Paganelli, C Albanese, m Cirulli, V La balestra, V Pannone, R Passariello, S Cucchiara. J Pediatr Gastr Nutr 40:644, PG2-12, 2005
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Terapia Combinata Farmacologica e con Laser a Diodi di Lichen Planus Orale (LPO): Case Report
No full textSystematic reviews to support evidence-based psychiatry: what about schizophrenia?
No full textOBJECTIVE: To assess whether systematic reviews (SRs), the gold standard for scientific research, can offer valuable support in evidence-based psychiatry in the treatment of schizophrenia.
METHODS: We used three database services (Ovid, PubMed and Cochrane) to identify SRs related to schizophrenia, found 163 reviews and grouped them by topic. We then evaluated each study's conclusions and divided them into three groups based on results (ranging from certain to null conclusions).
RESULTS: SRs of pharmacological treatments represented 59% of the studies sampled, only 23% of which had reached certain conclusions. Other clinical topics were less frequently represented and had achieved lower degrees of certainty.
CONCLUSIONS: Only 40 SRs (22 studies investigating pharmacological treatment) provided clear-cut answers to clinical questions examined. Results therefore showed that SRs provide a certain but rather limited contribution to scientific evidence in the field of schizophrenia
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