A graph is Hamiltonian if it contains a cycle passing through every vertex exactly once. A celebrated theorem of Dirac from 1952 asserts that every graph on n ≥ 3 vertices with minimum degree at least n/2 is Hamiltonian. We refer to such graphs as Dirac graphs. In this paper we obtain the following strengthening of this result. Given a graph G = (V,E), an incompatibility system F over G is a fa...

UNLABELLED PREMISE OF THE STUDY We examined two accounts of the relationship between breeding system and life history variation in a clade of evening primroses (Oenothera, Onagraceae): (1) selection for reproductive assurance should generate an association between self-compatibility and monocarpy and (2) phylogenetic conservatism leads to retention of breeding system and life history traits ...

There are four forms of hydatid disease. Echinococcus granulosus (EG) is the most common and gives rise to cystic hydatid disease (CHD), which is the focus of this review. Echinococcus multilocularis is uncommon and causes alveolar hydatid disease (AHD), which is far more aggressive and frequently mimics malignancy. The rarest clinical form is Echinococcus vogeli or polycystic hydatid disease (...

Adipose stem cells, which reside in a vascular niche, are essential to the development and maintenance of adipose tissue. Data from humans and rodents show that maintenance of adult adipose tissue is a dynamic process. Adipocyte turnover in young adult mice is estimated to be greater than 10% per month. The adipose stem cell niche is just as active, generating new adipocytes and replenishing th...

First recognised as 'schizonts' of Trypanosoma cruzi, Pneumocystis organisms are now considered as part of an early-diverging lineage of Ascomycetes. As no robust long-term culture model is available, most data on the Pneumocystis cell cycle have stemmed from ultrastructural images of infected mammalian lungs. Although most fungi developing in animals do not complete a sexual cycle in vivo, Pne...

Papillomaviruses infect epithelial cells, and depend on epithelial differentiation for completion of their life cycle. The expression of viral gene products is closely regulated as the infected basal cell migrates towards the epithelial surface. Expression of E6 and E7 in the lower epithelial layers drives cells into S-phase, which creates an environment that is conducive for viral genome repli...