11,871 research outputs found
Tensor-based trapdoors for CVP and their application to public key cryptography
We propose two trapdoors for the Closest-Vector-Problem in lattices (CVP) related to the lattice tensor product. Using these trapdoors we set up a lattice-based cryptosystem which resembles to the McEliece scheme
Assessment of tillage systems in organic farming: influence of soil structure on microbial biomass. First results
Soil tillage modifies environmental conditions of soil microorganisms and their ability to release nitrogen. We compare the influence of reduced tillage (RT) and mouldboard ploughing (MP) on the soil microbial functioning in organic farming. In order to connect soil structure generated by these tillage systems on the soil microbial biomass we adopt a particular sampling scheme based on the morphological characterisation of the soil structure by the description of the soil profile. This method reveals the influence of soil structure on soil microbial biomass and allows a more precise assessment of the impact of tillage managements on the soil microbial functioning
Unusual presentation of acute annular urticaria: A case report
Acute urticarial lesions may display central clearing with ecchymotic or haemorrhagic hue, often misdiagnosed as erythema
multiforme, serum-sickness-like reactions, or urticarial vasculitis. We report a case of acute annular urticaria with unusual
presentation occurring in a 20-month-old child to emphasize the distinctive morphologic manifestations in a single disease.
Clinicians who care for children should be able to differentiate acute urticaria from its clinical mimics. A directed history and
physical examination can reliably orientate necessary diagnostic testing and allow for appropriate treatment
Spatial-Structural Relations among Technology Industrial Clusters: A Comparative Analysis of Metropolitan Regions in the U.S
Technical industrial clusters are defined and analyzed for a sample of U.S. metropolitan regions. Economic structure, spatial proximity and shape of the clusters are examined across the metropolitan regions through various economic and spatial measures and statistics. The data for this research are used to test the hypothesis that close spatial proximity results in stronger economic functional interdependence. This hypothesis is examined and the implications of the test are explored.
Ecological intuition versus economic "reason"
This article discusses the discount rate to be used in projects that aimed at improving the environment. The model has two different goods, one is the usual consumption good whose production may increase exponentially, the other is an environmental good whose quality remains limited. The stylized world we describe is fully determined by four parameters, reflecting basic preferences "ecological" and intergenerational concerns and feasibility constraints. We define an ecological discount rate and examine its connections with the usual interest rate and the optimized growth rate. We discuss, in this simple world, a variety of forms of the precautionary principle.discount rate ; ecological discount rate ; environmental goods ; relative prices ; irreversible damage ; precautionnary principle
Geometric mutual information at classical critical points
A practical use of the entanglement entropy in a 1d quantum system is to
identify the conformal field theory describing its critical behavior. It is
exactly for an interval of length in an infinite system,
where is the central charge of the conformal field theory. Here we define
the geometric mutual information, an analogous quantity for classical critical
points. We compute this for 2d conformal field theories in an arbitrary
geometry, and show in particular that for a rectangle cut into two rectangles,
it is proportional to . This makes it possible to extract in classical
simulations, which we demonstrate for the critical Ising and 3-state Potts
models.Comment: 5 pages. v3: published versio
Linear diffusion with singular absorption potential and/or unbounded convective flow: the weighted space approach
In this paper we prove the existence and uniqueness of very weak solutions to
linear diffusion equations involving a singular absorption potential and/or an
unbounded convective flow on a bounded open set of . In most of
the paper we consider homogeneous Dirichlet boundary conditions but we prove
that when the potential function grows faster than the distance to the boundary
to the power -2 then no boundary condition is required to get the uniqueness of
very weak solutions. This result is new in the literature and must be
distinguished from other previous results in which such uniqueness of solutions
without any boundary condition was proved for degenerate diffusion operators
(which is not our case). Our approach, based on the treatment on some distance
to the boundary weighted spaces, uses a suitable regularity of the solution of
the associated dual problem which is here established. We also consider the
delicate question of the differentiability of the very weak solution and prove
that some suitable additional hypothesis on the data is required since
otherwise the gradient of the solution may not be integrable on the domain
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