The effects of land cover on urban-rural and intra-urban temperature differences have been extensively documented. However, few studies have quantitatively related air temperature to land cover composition at a local scale which may be useful to guide landscape planning and design. In this study, the quantitative relationships between air temperature and land cover composition at a neighborhood...

In many tropical regions, slash-and-burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest. We propose a reclamation strategy for abandoned fi...

Water scarcity contributes to the poverty of around one-third of the world's people. Despite many benefits, tree planting in dry regions is often discouraged by concerns that trees reduce water availability. Yet relevant studies from the tropics are scarce, and the impacts of intermediate tree cover remain unexplored. We developed and tested an optimum tree cover theory in which groundwater rec...

Introduction In many circumstances in afforestation, by tree plantation or by direct tree seeding, the quick development of very competitive herbaceous and shrubby species can compromise tree establishment (Balandier et al. 2006). At present, this vegetation is often controlled by chemical and mechanical operations, whereas they are criticized from environmental points of view; some alternative...

For simple random walk on a finite tree, the cover time is the time taken to visit every vertex. For the balanced b-ary tree of height m, the cover time is shown to be asymptotic to 2mb(log b)/(b− 1) as m→∞. On the uniform random labeled tree on n vertices, we give a convincing heuristic argument that the mean time to cover and return to the root is asymptotic to 6(2π)n, and prove a weak O(n) u...

A subset S of vertices of a graph G is called a k-path vertex cover if every path of order k in G contains at least one vertex from S. Denote by ψk(G) the minimum cardinality of a k-path vertex cover in G. In this paper improved lower and upper bounds for ψk of the Cartesian and the direct product of paths are derived. It is shown that for ψ3 those bounds are tight. For the lexicographic produc...

We are going to analyze simple search tree algorithms for Weighted d-Hitting Set. Although the algorithms are simple, their analysis is technically rather involved. However, this approach allows us to even improve on elsewhere previously published running time estimates for the more restricted case of (unweighted) d-Hitting Set. 1

To achieve fast link failure detection in all-optical networks, the notion of monitoring-cycle (m-cycle) is introduced. The best known m-cycle construction algorithm (HST [7]) adopts a spanning tree-based approach. In this paper, we propose a new algorithm M-CYCLE to construct a set of minimum-length mcycles (or m-cycles) for more efficient link failure detection. We prove that the performance ...

We determine the worst case information rate for all secret sharing schemes based on trees. It is the inverse of 2 − 1/c, where c is the size of the maximal core in the tree. A core is a connected subset of the vertices so that every vertex in the core has a neighbor outside the core. The upper bound comes from an application of the entropy method [2, 3], while the lower bound is achieved by a ...

Moist savannas and tropical forests share the same climatic conditions and occur side by side. Experimental evidences show that the tree cover of these ecosystems exhibits a bimodal frequency distribution. This is considered as a proof of savanna-forest bistability, predicted by dynamic vegetation models based on non-linear differential equations. Here, we propose a change of perspective about ...