Understanding stochastic perturbation theory: toy models and statistical analysis

The numerical stochastic perturbation method based on Parisi-Wu quantisationis applied to a suite of simple models to test its validity at high orders.Large deviations from normal distribution for the basic estimators aresystematically found in all cases (``Pepe effect''). As a consequence oneshould be very careful in estimating statistical errors. We present someresults obtained on Weingarten's ``pathological'' model where reliable resultscan be obtained by an application of the bootstrap method. We also present someevidence that in the far less trivial application to Lattice Gauge Theory asimilar problem should not arise at moderately high loops (up toO(\alpha^{10}))

Language diversity in urban landscapes: An econometric study

This multidisciplinary study adopts econometric analysis for investigating how different characteristics determine the choice of the language used in the signs of a shopping street. We work with a dataset containing about 200 observations collected in the main shopping streets of the cities of Donostia (Spain) and Ljouwert (The Netherlands). The results corroborate the important assumption that multilingualism and the choice of the language (even in a street sign) is an individual and a social preference. Therefore, understanding individuals' linguistic preference structures is preliminary to the target and design of proper linguistic and social policies

Developments and new applications of numerical stochastic perturbation theory

A review of new developments in numerical stochastic perturbation theory (NSPT) is presented. In particular, the status of the extension of the method to gauge fixed lattice QCD is reviewed and a first application to compact (scalar) QED is presented. Lacking still a general proof of the convergence of the underlying stochastic processes, a self-consistent method for testing the results is discussed.Comment: 3 pages, 1 figure. Poster presented at the Lattice97 conference, Edinburgh, U

New issues for Numerical Stochastic Perturbation Theory

First attempts in the application of Numerical Stochastic Perturbation Theory (NSPT) to the problem of pushing one loop further the computation of SU(3) (SU(2)) pertubative beta function (in different schemes) are reviewed and the relevance of such a computation is discussed. Other issues include the proposal of a different strategy for gauge-fixed NSPT computations in lattice QCD.Comment: 3 pages, Latex, LATTICE98(algorithms

BIOMEX (Biology and Mars Experiment): Preliminary results on Antarctic black cryptoendolithic fungi in ground based experiments

The main goal for astrobiologists is to find traces of present or past life in extraterrestrial environment or in meteorites. Biomolecules, such as lipids, pigments or polysaccharides, may be useful to establish the presence of extant or extinct life (Simoneit, B et al., 1998). BIOMEX (Biology and Mars Experiment) aims to measure to what extent biomolecules, such as pigments and cellular components, preserve their stability under space and Mars-like conditions. The experiment has just been launched in the space and will be exposed on EXPOSE-R payload to the outside of the International Space Station (ISS) for about 2 years. Among a number of extremophilic microorganisms tested, the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 was included in the experiment. The fungus, living in the airspaces of porous rocks, was already chosen in previous astrobiological investigation for studying the interplanetary transfer of life via meteorites. In that context, the fungus survived 18 months of exposure outside of the ISS (Onofri al., 2012); for all these reasons it is considered an optimal eukaryotic model for astrobiological exploration. Before launch dried samples were exposed, in ground based experiments, to extreme conditions, including vacuum, irradiation and temperature cycles.Upon sample re-hydration and survival analysis, including colony forming ability, Propidium MonoAzide (PMA) assay-coupled quantitative PCR (Mohapatra and La Duc, 2012) all the test systems survived, neither any DNA damage was detectable. Our analyses focused also on mineral-microorganisms interactions and stability/degradation of typical fungal macromolecules, in particular melanin, when exposed to space and simulated Martian conditions, contributing to the development of libraries of biosignatures in rocks, supporting future exploration missions

Equation of Motion for a Spin Vortex and Geometric Force

The Hamiltonian equation of motion is studied for a vortex occuring in 2-dimensional Heisenberg ferromagnet of anisotropic type by starting with the effective action for the spin field formulated by the Bloch (or spin) coherent state. The resultant equation shows the existence of a geometric force that is analogous to the so-called Magnus force in superfluid. This specific force plays a significant role for a quantum dynamics for a single vortex, e.g, the determination of the bound state of the vortex trapped by a pinning force arising from the interaction of the vortex with an impurity.Comment: 13 pages, plain te

A numerical study of the RG equation for the deformed O(3)O(3) nonlinear sigma model

The Renormalization Group equation describing the evolution of the metric of the nonlinear sigma model poses some nice mathematical problems involving functional analysis, differential geometry and numerical analysis. In this article we briefly report some results obtained from the numerical study of the solutions in the case of a two dimensional target space (deformation of the $O(3)$ sigma model). In particular, our analysis shows that the so-called sausages define an attracting manifold in the $U(1)$-symmetric case, at one-loop level. Moreover, data from two-loop evolution are used to test the association put forward in Nucl. Phys., B406 (1993) 521 between the so-called $SSM_{\nu}$ field theory and a certain $U(1)$-symmetric, factorized scattering theory (FST).Comment: LaTex (RevTex style), 16 pages, 6 uuencoded figures. Minor technical changes

The Higher Derivative Expansion of the Effective Action by the String-Inspired Method, Part I

The higher derivative expansion of the one-loop effective action for an external scalar potential is calculated to order O(T**7), using the string-inspired Bern-Kosower method in the first quantized path integral formulation. Comparisons are made with standard heat kernel calculations and with the corresponding Feynman diagrammatic calculation in order to show the efficiency of the present method.Comment: 13 pages, Plain TEX, 1 figure may be obtained from the authors, HD-THEP-93-4

Pricing agricultural inputs from biodiversity-rich ecosystems and habitats without input markets

Purpose: The purpose of this paper is to focus on the analysis of an understudied problem in the economic literature. It proposes a valuation methodology for inputs that come from biodiversity-rich ecosystems/habitats and are used in agro-food production at zero input cost because there is not a market for such inputs. Design/methodology/approach: Following Onofri et al. (2017), the authors computed the value of the marginal productivity of different inputs in three selected case studies (Angola, Mozambique and Brazil). Results are theory based and rigorous but show a strong contingency, case based, relative dimension that is captured, in the framework, by the \u201crelativity ratio.\u201d The ratio expresses the relative weight of the value generated by the input that comes from biodiversity-rich ecosystems/habitats in the per capita monthly available income of the farmer and aims at conveying additional insights to the economic valuation. Findings: In this paper, the assessment of agricultural inputs value (price) in the absence of inputs markets is done, with an application to three different case studies. The inputs are peculiar since they come from habitats and ecosystems that are very biodiversity-rich. Originality/value: The paper proposes a practical, though rigorous, methodology for the assessment of the value (price) of agricultural inputs in absence of inputs markets. Markets do not exist since the inputs come from biodiversity-rich habitats and ecosystems

Decomposition of Hilbert space in sets of coherent states

Within the generalized definition of coherent states as group orbits we study the orbit spaces and the orbit manifolds in the projective spaces constructed from linear representations. Invariant functions are suggested for arbitrary groups. The group SU(2) is studied in particular and the orbit spaces of its j=1/2 and j=1 representations completely determined. The orbits of SU(2) in CP^N can be either 2 or 3 dimensional, the first of them being either isomorphic to S^2 or to RP^2 and the latter being isomorphic to quotient spaces of RP^3. We end with a look from the same perspective to the quantum mechanical space of states in particle mechanics.Comment: revtex, 13 pages, 12 figure