Elements for the Expected Mechanisms on Reduced Emissions from Deforestation and Degradation, REDD under UNFCCC

Carbon emissions from deforestation and degradation account for 20% of the global anthropogenic emissions (IPCC WG I, 2007). Since the eleventh session of the Conference of the Parties to the United Nations Convention on Climate Change (UNFCCC) in December 2005, strategies and incentives for Reduced Emissions from Deforestation and Degradation (REDD) have emerged as one of the most attended negotiation items. It is not easy to build an international agreement on the role of REDD in a future climate change regime, but now we are close to an achievable historical decision on the future of forests: the Bali mandate on REDD. In this paper we suggest some elements for an effective long-term implementation of a REDD mechanism under the UNFCCC and for closing gaps in the forestry accounting system. These elements are related both to ecological and political processes, reflecting some of the most critical and debated negotiation points. The proposed elements are: a) carbon (C) losses from forests; b) incentives for all stages of reducing emissions, stabilizing and maintaining forest C stocks; c) national approach; d) data availability at national scale; e) conservativeness approach for carbon accounting.JRC.H.2-Climate chang

Crossing-Free Acyclic Hamiltonian Path Completion for Planar st-Digraphs

In this paper we study the problem of existence of a crossing-free acyclic hamiltonian path completion (for short, HP-completion) set for embedded upward planar digraphs. In the context of book embeddings, this question becomes: given an embedded upward planar digraph $G$, determine whether there exists an upward 2-page book embedding of $G$ preserving the given planar embedding. Given an embedded $st$-digraph $G$ which has a crossing-free HP-completion set, we show that there always exists a crossing-free HP-completion set with at most two edges per face of $G$. For an embedded $N$-free upward planar digraph $G$, we show that there always exists a crossing-free acyclic HP-completion set for $G$ which, moreover, can be computed in linear time. For a width-$k$ embedded planar $st$-digraph $G$, we show that we can be efficiently test whether $G$ admits a crossing-free acyclic HP-completion set.Comment: Accepted to ISAAC200

Three-Dimensional Grid Drawings with Sub-Quadratic Volume

A three-dimensional grid drawing of a graph is a placement of the vertices at distinct points with integer coordinates, such that the straight line-segments representing the edges are pairwise non-crossing. A O(n^{3/2}) volume bound is proved for three-dimensional grid drawings of graphs with bounded degree, graphs with bounded genus, and graphs with no bounded complete graph as a minor. The previous best bound for these graph families was O(n^2). These results (partially) solve open problems due to Felsner, Wismath, and Liotta [Graph Drawing 2001] and Pach, Thiele, and Toth [Graph Drawing 1997]

Embedding Plane 3-Trees in ℝ2 and ℝ3

A point-set embedding of a planar graph G with n vertices on a set P of n points in Rd , d ≥ 1, is a straight-line drawing of G, where the vertices of G are mapped to distinct points of P . The problem of computing a point-set embedding of G on P is NP-complete in R2 , even when G is 2-outerplanar and the points are in general position. On the other hand, if the points of P are in general position in R3 , then any bijective mapping of the vertices of G to the points of P determines a point-set embedding of G on P . In this paper, we give an O(n4/3+ )-expected time algorithm to decide whether a plane 3-tree with n vertices admits a point-set embedding on a given set of n points in general position in R2 and compute such an embedding if it exists, for any fixed >0. We extend our algorithm to embed a subclass of 4-trees on a point set in R3 in the form of nested tetrahedra. We also prove that given a plane 3-tree G with n vertices, a set P of n points in R3 that are not necessarily in general position and a mapping of the three outer vertices of G to three different points of P , it is NP-complete to decide if G admits a point-set embedding on P respecting the given mapping

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

Measurement of electrons from semileptonic heavy-flavour hadron decays at midrapidity in pp and Pb–Pb collisions at √sNN = 5.02 TeV

The differential invariant yield as a function of transverse momentum (pT) of electrons from semileptonic heavy-flavour hadron decays was measured at midrapidity in central (0–10%), semi-central (30–50%) and peripheral (60–80%) lead–lead (Pb–Pb) collisions at √sNN = 5.02 TeV in the pT intervals 0.5–26 GeV/c (0–10% and 30–50%) and 0.5–10 GeV/c (60–80%). The production cross section in proton–proton (pp) collisions at √s = 5.02 TeV was measured as well in 0.5 < pT < 10 GeV/c and it lies close to the upper band of perturbative QCD calculation uncertainties up to pT = 5 GeV/c and close to the mean value for larger pT. The modification of the electron yield with respect to what is expected for an incoherent superposition of nucleon–nucleon collisions is evaluated by measuring the nuclear modification factor RAA. The measurement of the RAA in different centrality classes allows in-medium energy loss of charm and beauty quarks to be investigated. The RAA shows a suppression with respect to unity at intermediate pT, which increases while moving towards more central collisions. Moreover, the measured RAA is sensitive to the modification of the parton distribution functions (PDF) in nuclei, like nuclear shadowing, which causes a suppression of the heavy-quark production at low pT in heavy-ion collisions at LHC