Deciding whether a collection of unrooted trees is compatible is a fundamental problem in phylogenetics. Two different graph-theoretic characterizations of tree compatibility have recently been proposed. In one of these, tree compatibility is characterized in terms of the existence of a specific kind of triangulation in a structure known as the display graph. An alternative characterization exp...

The P4-sparse Graph Sandwich Problem asks, given two graphs G 1 = (V, E1) and G2 = (V, E2), whether there exists a graph G = (V, E) such that E1 ⊆ E ⊆ E2 and G is P4-sparse. In this paper we present a polynomial-time algorithm for solving the Graph Sandwich Problem for P4-sparse graphs. c © 2008 Elsevier B.V. All rights reserved.

In this paper we introduce the simultaneous membership problem, defined for any graph class C characterized in terms of representations, e.g. any class of intersection graphs. Two graphs G1 and G2, sharing some vertices X (and the corresponding induced edges), are said to be simultaneous members of graph class C, if there exist representations R1 and R2 of G1 and G2 that are “consistent” on X ....

A graph is a 1-join composition if its vertex set can be partitioned into four nonempty sets AL; AR ; SL and SR such that: every vertex of AL is adjacent to every vertex of AR; no vertex of SL is adjacent to vertex of AR∪SR; no vertex of SR is adjacent to a vertex of AL∪SL. The graph sandwich problem for 1-join composition is de9ned as follows: Given a vertex set V , a forced edge set E, and a ...

conclusions our study demonstrated that tgf-β1 serum levels is higher in osteoporotic postmenopausal females than non-osteoporotic ones, and probably aberrant increase in tgf-β1 in postmenopausal females can result in uncoupled bone resorption and formation, which leads to osteoporosis. background postmenopausal osteoporosis is a major cause of morbidity in postmenopausal females. transforming ...

The Japanese quail has been utilized as a research species in establishing the genetic relationships that may also be present in other species. Divergent phenotypic selection for 4-wk BW was conducted for three generations in high (HW) and low (LW) lines. Within each line, 50 females and 25 males were selected among 600 birds, based on 4-wk BW. Mean BW at 4 wk of age in the base generation was ...

In the present work we present a systematic experimental investigation of the generation and subsequent evolution of dynamic failure modes in sandwich structures subjected to low-speed impact. Model sandwich specimens involving a compliant polymer core sandwiched between two metal layers were designed and subjected to impact loading to simulate failure evolution mechanisms in real sandwich stru...

Increasingly, women simultaneously balance the roles of mother, parental carer and worker. However, individual role balance strategies among these working 'sandwich' generation women have not been thoroughly explored. Eighteen women combining these three roles were interviewed about their individual role balance strategies. Findings were identified through the framework analysis technique, unde...

The challenge of safe hydrogen storage has limited the practical application of solar-driven photocatalytic water splitting. It is hard to isolate hydrogen from oxygen products during water splitting to avoid unwanted reverse reaction or explosion. Here we propose a multi-layer structure where a carbon nitride is sandwiched between two graphene sheets modified by different functional groups. Fi...