6,046 research outputs found

    Warm glow and embedding in contingent valuation

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    This paper reports the results from a contingent valuation study designed to investigate the influence of warm glow in willingness-to-pay responses. Interindividual differences in warm glow motivation are measured through a factor analysis, performed on a list of attitudinal items. The reported willingness to pay measures fail to pass the scope test. Both socioeconomic variables and motivational factor scores are significant in the explanation of the individual WTP measures. We compute dry WTP measures by taking out the effect of the warm glow motivation. These dry measures satisfy both the scope test and Hausman's adding-up property and could therefore be interpreted as reflecting true economic preferences

    Splash control of drop impacts with geometric targets

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    Drop impacts on solid and liquid surfaces exhibit complex dynamics due to the competition of inertial, viscous, and capillary forces. After impact, a liquid lamella develops and expands radially, and under certain conditions, the outer rim breaks up into an irregular arrangement of filaments and secondary droplets. We show experimentally that the lamella expansion and subsequent break up of the outer rim can be controlled by length scales that are of comparable dimension to the impacting drop diameter. Under identical impact parameters, ie. fluid properties and impact velocity, we observe unique splashing dynamics by varying the target cross-sectional geometry. These behaviors include: (i) geometrically-shaped lamellae and (ii) a transition in splashing stability, from regular to irregular splashing. We propose that regular splashes are controlled by the azimuthal perturbations imposed by the target cross-sectional geometry and that irregular splashes are governed by the fastest-growing unstable Plateau-Rayleigh mode

    Marine ecosystem services: Linking indicators to their classification

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    © 2014 Elsevier Ltd. All rights reserved. There is a multitude of ecosystem service classifications available within the literature, each with its own advantages and drawbacks. Elements of them have been used to tailor a generic ecosystem service classification for the marine environment and then for a case study site within the North Sea: the Dogger Bank. Indicators for each of the ecosystem services, deemed relevant to the case study site, were identified. Each indicator was then assessed against a set of agreed criteria to ensure its relevance and applicability to environmental management. This paper identifies the need to distinguish between indicators of ecosystem services that are entirely ecological in nature (and largely reveal the potential of an ecosystem to provide ecosystem services), indicators for the ecological processes contributing to the delivery of these services, and indicators of benefits that reveal the realized human use or enjoyment of an ecosystem service. It highlights some of the difficulties faced in selecting meaningful indicators, such as problems of specificity, spatial disconnect and the considerable uncertainty about marine species, habitats and the processes, functions and services they contribute to

    Policy instruments for creating markets for biodiversity: Certification and ecolabing

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    This paper provides an economic evaluation of certification and ecolabeling as an important policy instrument for creating markets for biodiversity. In the paper we conclude that the success of a policy instrument for creating markets for biodiversity depends on the nature crucial factors, including the ability of the policy instrument to deal with (a) the public good nature of most of the nonmarket biodiversity benefits; (b) the asymmetric informational characteristics related to the biodiversity (and environmental friendly) market supply and demand mechanisms; (c) the impact of certification practices in the producer's costs, and (d) the cross price elasticity between regular and market certified products. Indeed, in some cases certification and ecolabeling policy instruments alone are not sufficient to guarantee a successful creation of markets for biodiversity. Finally, the certification schemes need to be sufficiently flexible to allow mutual recognition among the countries involved, as well as to meet the demand of weak sensitive markets. By mutual understanding, and learning with the past experiences, certification and ecolabeling will positively contribute to the creation of markets for biodiversity and thus expected to assist to the development of an effective and broadly accepted sustainable management of such a scarce natural resource

    Language diversity in urban landscapes: An econometric study

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    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

    Mechanical detection of carbon nanotube resonator vibrations

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    Bending-mode vibrations of carbon nanotube resonator devices were mechanically detected in air at atmospheric pressure by means of a novel scanning force microscopy method. The fundamental and higher order bending eigenmodes were imaged at up to 3.1GHz with sub-nanometer resolution in vibration amplitude. The resonance frequency and the eigenmode shape of multi-wall nanotubes are consistent with the elastic beam theory for a doubly clamped beam. For single-wall nanotubes, however, resonance frequencies are significantly shifted, which is attributed to fabrication generating, for example, slack. The effect of slack is studied by pulling down the tube with the tip, which drastically reduces the resonance frequency

    n-Dimensional FLRW Quantum Cosmology

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    We introduce the formalism of quantum cosmology in a Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe of arbitrary dimension filled with a perfect fluid with p=αρp=\alpha\rho equation of state. First we show that the Schutz formalism, developed in four dimensions, can be extended to a n-dimensional universe. We compute the quantum representant of the scale factor a(t)a(t), in the Many-Worlds, as well as, in the de Broglie-Bohm interpretation of quantum mechanics. We show that the singularities, which are still present in the n-dimensional generalization of FLRW universe, are excluded with the introduction of quantum theory. We quantize, via the de Broglie-Bohm interpretation of quantum mechanics, the components of the Riemann curvature tensor in a tetrad basis in a n-dimensional FLRW universe filled with radiation (p=1n1ρp=\frac{1}{n-1}\rho). We show that the quantized version of the Ricci scalar are perfectly regular for all time tt. We also study the behavior of the energy density and pressure and show that the ratio L/L_L/_L tends to the classical value 1/(n1)1/(n-1) only for n=4n=4, showing that n=4n=4 is somewhat privileged among the other dimensions. Besides that, as nn\to\infty, L/L1_L/_L\to 1.Comment: 12 pages, revtex, minor modification

    Spatial and temporal variability of precipitation and drought in Portugal

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    The spatial variability of precipitation and drought are investigated for Portugal using monthly precipitation from 74 stations and minimum and maximum temperature from 27 stations, covering the common period of 1941–2006. Seasonal precipitation and the corresponding percentages in the year, as well as the precipitation concentration index (PCI), was computed for all 74 stations and then used as an input matrix for an R-mode principal component analysis to identify the precipitation patterns. The standardized precipitation index at 3 and 12 month time scales were computed for all stations, whereas the Palmer Drought Severity Index (PDSI) and the modified PDSI for Mediterranean conditions (MedPDSI) were computed for the stations with temperature data. The spatial patterns of drought over Portugal were identified by applying the S-mode principal component analysis coupled with varimax rotation to the drought indices matrices. The result revealed two distinct sub-regions in the country relative to both precipitation regimes and drought variability. The analysis of time variability of the PC scores of all drought indices allowed verifying that there is no linear trend indicating drought aggravation or decrease. In addition, the analysis shows that results for SPI-3, SPI-12, PDSI and MedPDSI are coherent among them

    Ecological-economic analysis and valuation of biodiversity

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    This paper introduces and surveys ecological-economic analysis and valuation of biodiversity. Furthermore, the notion and application of economic, monetary valuation of biodiversity is critically evaluated. A classification of biodiversity values is offered, based on a system of logical relationships among biodiversity, ecosystems, species and human welfare. Suggestions are made about which economic valuation methods can address which type of biodiversity value. The resulting framework is the starting point for a survey and evaluation of empirical studies at each of the four levels of diversity. The resulting monetary value estimates seem to give unequivocal support to the belief that biodiversity has a significant, positive social value. The contingent valuation method is by far the most used method. An important reason is that the other valuation methods are unable to identify and measure passive or nonuse values of biodiversity. Nevertheless, most studies lack a uniform, integrated perspective on biodiversity. Therefore, available economic valuation estimates should generally be regarded as providing a partial perspective on, and at best lower bounds, to the unknown value of biodiversity changes

    Quantum corrections to gravity and their implications for cosmology and astrophysics

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    The quantum contributions to the gravitational action are relatively easy to calculate in the higher derivative sector of the theory. However, the applications to the post-inflationary cosmology and astrophysics require the corrections to the Einstein-Hilbert action and to the cosmological constant, and those we can not derive yet in a consistent and safe way. At the same time, if we assume that these quantum terms are covariant and that they have relevant magnitude, their functional form can be defined up to a single free parameter, which can be defined on the phenomenological basis. It turns out that the quantum correction may lead, in principle, to surprisingly strong and interesting effects in astrophysics and cosmology.Comment: 15 pages, LaTeX, WS style, contribution to the Proceedings of the QFEXT-2011 conference in the Centro de Ciencias de Benasque Pedro Pasqual, Spai
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