1,433 research outputs found
Potentials and Limits of Bayesian Networks to Deal with Uncertainty in the Assessment of Climate Change Adaptation Policies
Bayesian networks (BNs) have been increasingly applied to support management and decision-making processes under conditions of environmental variability and uncertainty, providing logical and holistic reasoning in complex systems since they succinctly and effectively translate causal assertions between variables into patterns of probabilistic dependence. Through a theoretical assessment of the features and the statistical rationale of BNs, and a review of specific applications to ecological modelling, natural resource management, and climate change policy issues, the present paper analyses the effectiveness of the BN model as a synthesis framework, which would allow the user to manage the uncertainty characterising the definition and implementation of climate change adaptation policies. The review will let emerge the potentials of the model to characterise, incorporate and communicate the uncertainty, with the aim to provide an efficient support to an informed and transparent decision making process. The possible drawbacks arising from the implementation of BNs are also analysed, providing potential solutions to overcome them.Adaptation to Climate Change, Bayesian Network, Uncertainty
Super Quantum Mechanics in the Integral Form Formalism
We reformulate Super Quantum Mechanics in the context of integral forms. This
framework allows to interpolate between different actions for the same theory,
connected by different choices of Picture Changing Operators (PCO). In this way
we retrieve component and superspace actions, and prove their equivalence. The
PCO are closed integral forms, and can be interpreted as super Poincar\'e duals
of bosonic submanifolds embedded into a supermanifold.. We use them to
construct Lagrangians that are top integral forms, and therefore can be
integrated on the whole supermanifold. The and the
cases are studied, in a flat and in a curved supermanifold. In this formalism
we also consider coupling with gauge fields, Hilbert space of quantum states
and observables.Comment: 41 pages, no figures. Use birkjour.cls. Minor misprints, moved
appendix A and B in the main text. Version to be published in Annales H.
Poincar\'
The Geometry of Supermanifolds and New Supersymmetric Actions
We construct the Hodge dual for supermanifolds by means of the Grassmannian
Fourier transform of superforms. In the case of supermanifolds it is known that
the superforms are not sufficient to construct a consistent integration theory
and that the integral forms are needed. They are distribution-like forms which
can be integrated on supermanifolds as a top form can be integrated on a
conventional manifold. In our construction of the Hodge dual of superforms they
arise naturally. The compatibility between Hodge duality and supersymmetry is
exploited and applied to several examples. We define the irreducible
representations of supersymmetry in terms of integral and superforms in a new
way which can be easily generalised to several models in different dimensions.
The construction of supersymmetric actions based on the Hodge duality is
presented and new supersymmetric actions with higher derivative terms are
found. These terms are required by the invertibility of the Hodge operator.Comment: LateX2e, 51 pages. Corrected some further misprint
Hodge Dualities on Supermanifolds
We discuss the cohomology of superforms and integral forms from a new
perspective based on a recently proposed Hodge dual operator. We show how the
superspace constraints (a.k.a. rheonomic parametrisation) are translated from
the space of superforms to the space of integral forms
where , is the bosonic dimension of the
supermanifold and its fermionic dimension. We dwell on the relation between
supermanifolds with non-trivial curvature and Ramond-Ramond fields, for which
the Laplace-Beltrami differential, constructed with our Hodge dual, is an
essential ingredient. We discuss the definition of Picture Lowering and Picture
Raising Operators (acting on the space of superforms and on the space of
integral forms) and their relation with the cohomology. We construct
non-abelian curvatures for gauge connections in the space and
finally discuss Hodge dual fields within the present framework.Comment: 35 page
Governance and Environmental Policy Integration in Europe: What Can We learn from the EU Emission Trading Scheme?
The European Union Emission Trading System (EU ETS) is a landmark environmental policy, representing the worldâs first large-scale greenhouse gas (GHG) trading program. The coexistence of state actors and top-down processes with stakeholders participation and flexible abatement strategies make the EU ETS a powerful instrument of cross sectoral integration of environmental concerns, which benefits from a high level of interaction among the actors involved and a significant degree of information exchange. However, the same peculiarities of the system make it difficult to identify a correspondence with a single mode of governance. The EU ETS shows characteristics of the decision making processes and institutions engaged, the tools and instruments used as well as the actors involved, which change according to the different levels of governance, and belong both to the old and to the new modes of governance. The emission trading scheme represents a clear example of Multi-Level governance, where the different modes of governance interact among them and affect each other.Environmental Policy Integration, Climate Change, Emission Trading, EU Policy
Population size estimation via alternative parametrizations for Poisson mixture models
We exploit a suitable moment-based reparametrization of the Poisson mixtures distributions for developing classical and Bayesian inference for the unknown size of a finite population in the presence of count data. Here we put particular emphasis on suitable mappings between ordinary moments and recurrence coefficients that will allow us to implement standard maximization routines and MCMC routines in a more convenient parameter space. We assess the comparative performance of our approach in real data applications and in a simulation study
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