10,122 research outputs found

    ESTIMATION OF EXTERNAL COSTS OF ELECTRICITY GENERATION USING EXTERNE MODEL

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    The external costs of electricity generation can be characterised by the resulting social and environmental impacts. The most significant impacts are the air pollutions impact on health, built in environment, crops, forests, agricultural areas and on global warming. The primary impact considered is the air pollution’s effect on human health. The monetised value of the health impact, the external costs are calculated for two regional coal power plants, the effects are examined on the EU level with the ExternE methodology.External costs, human health, monetized environmental impacts, energy production, coal power plants, air pollution, Environmental Economics and Policy, Health Economics and Policy, Research Methods/ Statistical Methods,

    Restoration Ecology: Two-Sex Dynamics and Cost Minimization

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    We model a spatially detailed, two-sex population dynamics, to study the cost of ecological restoration. We assume that cost is proportional to the number of individuals introduced into a large habitat. We treat dispersal as homogeneous diffusion. The local population dynamics depends on sex ratio at birth, and allows mortality rates to differ between sexes. Furthermore, local density dependence induces a strong Allee effect, implying that the initial population must be sufficiently large to avert rapid extinction. We address three different initial spatial distributions for the introduced individuals; for each we minimize the associated cost, constrained by the requirement that the species must be restored throughout the habitat. First, we consider spatially inhomogeneous, unstable stationary solutions of the model's equations as plausible candidates for small restoration cost. Second, we use numerical simulations to find the smallest cluster size, enclosing a spatially homogeneous population density, that minimizes the cost of assured restoration. Finally, by employing simulated annealing, we minimize restoration cost among all possible initial spatial distributions of females and males. For biased sex ratios, or for a significant between-sex difference in mortality, we find that sex-specific spatial distributions minimize the cost. But as long as the sex ratio maximizes the local equilibrium density for given mortality rates, a common homogeneous distribution for both sexes that spans a critical distance yields a similarly low cost

    Eastern European and Soviet literature of the present age*

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    I am not an expert on the literature of Eastern Europe and the Soviet Union but coming from that part of the world and reading some of the relevant languages I feel that I can comment with some degree of authority on the current state of the literature in the countries being the Iron Curtain

    Free Form Lensing Implications for the Collision of Dark Matter and Gas in the Frontier Fields Cluster MACSJ0416.1-2403

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    We present a free form mass reconstruction of the massive lensing cluster MACSJ0416.1-2403 using the latest Hubble Frontier Fields data. Our model independent method finds that the extended lensing pattern is generated by two elongated, closely projected clusters of similar mass. Our lens model identifies new lensed images with which we improve the accuracy of the dark matter distribution. We find that the bimodal mass distribution is nearly coincident with the bimodal X-ray emission, but with the two dark matter peaks lying closer together than the centroids of the X-ray emisison. We show this can be achieved if the collision has occurred close to the plane and such that the cores are deflected around each other. The projected mass profiles of both clusters are well constrained because of the many interior lensed images, leading to surprisingly flat mass profiles of both components in the region 15-100 kpc. We discuss the extent to which this may be generated by tidal forces in our dynamical model which are large during an encounter of this type as the cores "graze" each other. The relative velocity between the two cores is estimated to be about 1200 km/s and mostly along the line of sight so that our model is consistent with the relative redshift difference between the two cD galaxies (dz = 0.04).Comment: 22 pages, 18 figures, 2 table

    The Development of Spontaneous Sound-Shape Matching in Monolingual and Bilingual Infants During the First Year

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    Online First November 17, 2016Supplemental materials: http://dx.doi.org/10.1037/dev0000237.suppRecently it has been proposed that sensitivity to nonarbitrary relationships between speech sounds and objects potentially bootstraps lexical acquisition. However, it is currently unclear whether preverbal infants (e.g., before 6 months of age) with different linguistic profiles are sensitive to such nonarbitrary relationships. Here, the authors assessed 4- and 12-month-old Basque monolingual and Spanish-Basque bilingual infants’ sensitivity to cross-modal correspondences between sound symbolic nonwords without syllable repetition (buba, kike) and drawings of rounded and angular shapes. The findings demonstrate that sensitivity to sound-shape correspondences emerge by 12 months of age in both monolinguals and bilinguals. This finding suggests that spontaneous sound-shape matching is likely to be the product of language learning and development and may not be readily available prior to the onset of word learning

    Consumer Purchasing Behaviors and Attitudes toward Shopping at Public Markets

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    This paper identifies and empirically evaluates factors that explain the variations in consumers’ attitudes toward shopping at farmers markets in general and public markets in particular. The analysis draws on data from a telephone survey conducted in Jefferson County, Alabama. Logit model results point to several factors that seem to be strongly correlated with consumer purchasing behaviors and attitudes toward shopping at public markets, including income, education, age of household head, household size, and price and quality of produce. The insights gained from the study should help farmers increase the profitability of their operations and improve the likelihood that they will continue farming.Consumer/Household Economics,

    The rotation group in plate tectonics and the representation of uncertainties of plate reconstructions

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    The calculation of the uncertainty in an estimated rotation requires a parametrization of the rotation group; that is, a unique mapping of the rotation group to a point in 3-D Euclidean space, R^3. Numerous parametrizations of a rotation exist, including: (1) the latitude and longitude of the axis of rotation and the angle of rotation; (2) a representation as a Cartesian vector with length equal to the rotation angle and direction parallel to the rotation axis; (3) Euler angles; or (4) unit length quaternions (or, equivalently, Cayley-Klein parameters). The uncertainty in a rotation is determined by the effect of nearby rotations on the rotated data. The uncertainty in a rotation is small, if rotations close to the best fitting rotation degrade the fit of the data by a large amount, and it is large, if only rotations differing by a large amount cause such a degradation. Ideally, we would like to parametrize the rotations in such a way so that their representation as points in R^3 would have the property that the distance between two points in R3 reflects the effects of the corresponding rotations on the fit of the data. It can be shown mathematically that this is impossible, but for rotations of small angle, it can be done to close approximation by using vectors in Cartesian coordinates. Thus, we are led to parametrizing the uncertainty separately from the parametrization of the best fitting rotation. This approach results in simpler, more efficient calculations than if uncertainties are described in terms of rotation parameters (i.e., latitude, longitude, and the angle). We illustrate this with the example of equations for determining the uncertainty in a composite rotation from the uncertainties of its constituents

    The eccentricity in heavy-ion collisions from Color Glass Condensate initial conditions

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    The eccentricity in coordinate-space at midrapidity of the overlap zone in high-energy heavy-ion collisions predicted by the kk_\perp-factorization formalism is generically larger than expected from scaling with the number of participants. We provide a simple qualitative explanation of the effect which shows that it is not caused predominantly by edge effects. We also show that it is quite insensitive to ``details'' of the unintegrated gluon distribution functions such as the presence of leading-twist shadowing and of an extended geometric scaling window. The larger eccentricity increases the azimuthal asymmetry of high transverse momentum particles. Finally, we point out that the longitudinal structure of the Color Glass Condensate initial condition for hydrodynamics away from midrapidity is non-trivial but requires understanding of large-xx effects.Comment: 8 pages, 7 figures; v3: added note regarding Qs2~n_part versus Qs2~T_A, final version to appear in PR

    Robustness of Planar Fourier Capture Arrays to Colour Changes and Lost Pixels

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    Planar Fourier capture arrays (PFCAs) are optical sensors built entirely in standard microchip manufacturing flows. PFCAs are composed of ensembles of angle sensitive pixels (ASPs) that each report a single coefficient of the Fourier transform of the far-away scene. Here we characterize the performance of PFCAs under the following three non-optimal conditions. First, we show that PFCAs can operate while sensing light of a wavelength other than the design point. Second, if only a randomly-selected subset of 10% of the ASPs are functional, we can nonetheless reconstruct the entire far-away scene using compressed sensing. Third, if the wavelength of the imaged light is unknown, it can be inferred by demanding self-consistency of the outputs.Comment: 15 pages including cover page, 12 figures, associated with the 9th International Conference on Position Sensitive Detector

    Non-parabolicity of the conduction band of wurtzite GaN

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    Using cyclotron resonance, we measure the effective mass, mm*, of electrons in AlGaN/GaN heterostructures with densities, n2D16×1012n_{2D}\sim 1-6\times10^{12}cm2^{-2}. From our extensive data, we extrapolate a band edge mass of (0.208±0.002)me(0.208\pm0.002) m_e. By comparing our mm* data with the results of a multi-band \textbf{k.p} calculation we infer that the effect of remote bands is essential in explaining the observed conduction band non-parabolicity (NP). Our calculation of polaron mass corrections -- including finite width and screening - suggests those to be negligible. It implies that the behavior of m(n2D)m*(n_{2D}) can be understood solely in terms of NP. Finally, using our NP and polaron corrections, we are able to reduce the large scatter in the published band edge mass values
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