Controversy over the origins and evolution of social behaviour in the major groups of social bees (the corbiculate bees) has fuelled arguments over different approaches for building evolutionary trees. However, the application of different analytical methodologies does not explain why molecular and morphological data suggest strikingly different hypotheses for the evolution of eusociality in be...

From California sequoia, to Australian eucalyptus, to the outstanding diversity of Amazonian forests, trees are fundamental to many processes in ecology and evolution. Trees define the communities that they inhabit, are host to a multiplicity of other organisms and can determine the ecological dynamics of other plants and animals. Trees are also at the heart of major patterns of biodiversity su...

We consider nearest-neighbour self-avoiding walk, bond percolation, lattice trees, and bond lattice animals on Z. The two-point functions of these models are respectively the generating function for self-avoiding walks from the origin to x ∈ Z, the probability of a connection from the origin to x, and the generating functions for lattice trees or lattice animals containing the origin and x. Usi...

background and aims: citrus exocortis disease is naturally limited to citrus plants and causes a serious disease on sensitive rootstocks such as trifoliate orange. the aim of this study was to sample new variants of citrus exocortis viroid from fars trees with yellowing and suberization symptoms and comparison with other isolates of this viroid. materials and methods: a number of symptomatic or...

over the past few decades, scientists have paid special attention to studying novel and natural hydrocolloids due to the growing demand for ready meals, public awareness on the importance of natural fibers in daily diets, and their wide range of application, especially in foods, pharmaceuticals and herbal medicine. moreover, natural hydrocolloids are preferred to biotechnologic ones (e.g., gell...

Background and Aims: Citrus exocortis disease is naturally limited to citrus plants and causes a serious disease on sensitive rootstocks such as trifoliate orange. The aim of this study was to sample new variants of citrus exocortis viroid from Fars trees with yellowing and suberization symptoms and comparison with other isolates of this viroid. Materials and Methods: A number of symptomat...

Motivated as a null model for comparison with data, we study the following model for a phylogenetic tree on n extant species. The origin of the clade is a random time in the past, whose (improper) distribution is uniform on (0,∞). After that origin, the process of extinctions and speciations is a continuous-time critical branching process of constant rate, conditioned on having the prescribed n...

kikuchi-fujimoto disease (kfd) is a benign, self-limiting disease characterized by histiocytic necrotising lymphadenitis. though several viral agents or an autoimmune etiology has been proposed as causative, the exact cause remains unknown. it has a female predilection and most commonly seen among young asian people. patients usually present with a febrile illness and the presence of lymphadeno...