Abstract Defence cases with an escalatory structure, in which the levels of violence between aggressor and defender start out as minor then become major, even lethal, raise sharp problems for defence theory, our understanding conditions defence: proportionality, necessity, imminence. It is argued here that defenders are not morally required to withdraw from participation these cases, defensive ...

Predator-prey interactions are major processes promoting phenotypic evolution. However, it remains unclear how predation causes morphological and behavioural diversity in prey species and how it might lead to speciation. Here, we show that substantial divergence in the phenotypic traits of prey species has occurred among closely related land snails as a result of adaptation to predator attacks....

A defensive k-alliance in a graph G = (V, E) is a set of vertices A ⊆ V such that for every vertex v ∈ A, the number of neighbors v has in A is at least k more than the number of neighbors it has in V − A (k is a measure of the strength of alliance). In this paper, we deal with two types of sets associated with defensive k-alliances; maximum defensive k-alliance free and minimum defensive k-all...

One of the major goals of the Sustainable Agriculture Farming initiatives at UC Davis is to provide information about the feasibility of adopting conservation tillage and cover cropping at the farm level. The project includes two tillage schemes: standard tillage (ST) and conservation tillage (CT), and three farming methods: conventional, organic, and winter legume cover crop. All three product...

Global biodiversity continues along a trajectory of decline despite enormous conservation efforts (Rands et al., 2010). This is also true in China, one of the most biodiversity-rich countries in the world (Liu and Raven, 2010; Ministry of Environmental Protection of China, 2010a). To fundamentally change this trajectory, it is essential to understand complex interactions among various forces af...