Nitrogen Partitioning in the Hazelnut Tree

The Complexity of Tree Partitioning

Given a tree T on n vertices, and k, b, s1, . . . , sb ∈ N, the Tree Partitioning problem asks if at most k edges can be removed from T so that the resulting components can be grouped into b groups such that the number of vertices in group i is si, for i = 1, . . . , b. The case when s1 = · · · = sb = n/b, referred to as the Balanced Tree Partitioning problem, was shown to be NP-complete for tr...

The R⊕-tree: Incorporating Object Partitioning into the R-tree

During the past three decades, researchers devoted much effort to developing efficient techniques to index spatial data. Of those proposed, the R-tree[1] is perhaps the most important. R-trees are ubiquitous in commercial database management systems, and they find myriad applications in other disciplines as well. In this paper, we seek to improve the state-of-the-art R-tree[2] by introducing sp...

Distribution of leaf mass per unit area and leaf nitrogen concentration determine partitioning of leaf nitrogen within tree canopies.

Distribution of leaf nitrogen with respect to leaf mass per unit area (M(a)), nitrogen per unit mass (N(m)) and nitrogen per unit area (N(a)) within peach (Prunus persica L.) tree canopies was studied in two field experiments. In one experiment, leaf light exposure and M(a) were measured on leaves from different canopy positions of peach trees subjected to five nitrogen (N) fertilization treatm...

Elemental nitrogen partitioning in dense interstellar clouds.

Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N(2), with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear diatomic molecule, N(2) is difficult to detect spectroscopically through infrared or millimeter-wavelength transitions. Therefore, its abundance is often inferr...

Carbon Partitioning in Nitrogen-fixing Root Nodules