4,941 research outputs found

    Five new records of coastal fishes from São Tomé Island

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    We report the presence of five fish species at São Tomé Island, which have not yet been described from there, and clarify the status of two unidentified species in a checklist published previously. Two of these species are amphi-Atlantic and the other five are only known from the coast of West-Africa.info:eu-repo/semantics/publishedVersio

    Morphological regions and oblique incidence dot formation in a model of surface sputtering

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    We study solid surface morphology created by off-normal ion-beam sputtering with an atomistic, solid-on-solid model of sputter erosion. With respect to an earlier version of the model, we extend this model with the inclusion of lateral erosion. Using the 2-dimensional structure factor, we found an upper bound μ2\mu\simeq 2, in the lateral straggle μ\mu, for clear ripple formation. Above this upper bound, for longitudinal straggle σ1.7\sigma\gtrsim 1.7, we found the possibility of dot formation (without sample rotation). Moreover, a temporal crossover from a hole topography to ripple topography with the same value of collision cascade parameters was found. Finally, a scaling analysis of the roughness, using the consecutive gradient approach, yields the growth exponents β=0.33\beta=0.33 and 0.67 for two different topographic regimes.Comment: 8 pages, 14 figure

    Possible indicators for low dimensional superconductivity in the quasi-1D carbide Sc3CoC4

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    The transition metal carbide Sc3CoC4 consists of a quasi-one-dimensional (1D) structure with [CoC4]_{\inft} polyanionic chains embedded in a scandium matrix. At ambient temperatures Sc3CoC4 displays metallic behavior. At lower temperatures, however, charge density wave formation has been observed around 143K which is followed by a structural phase transition at 72K. Below T^onset_c = 4.5K the polycrystalline sample becomes superconductive. From Hc1(0) and Hc2(0) values we could estimate the London penetration depth ({\lambda}_L ~= 9750 Angstroem) and the Ginsburg-Landau (GL) coherence length ({\xi}_GL ~= 187 Angstroem). The resulting GL-parameter ({\kappa} ~= 52) classifies Sc3CoC4 as a type II superconductor. Here we compare the puzzling superconducting features of Sc3CoC4, such as the unusual temperature dependence i) of the specific heat anomaly and ii) of the upper critical field H_c2(T) at T_c, and iii) the magnetic hysteresis curve, with various related low dimensional superconductors: e.g., the quasi-1D superconductor (SN)_x or the 2D transition-metal dichalcogenides. Our results identify Sc3CoC4 as a new candidate for a quasi-1D superconductor.Comment: 4 pages, 5 figure

    Influence of Dilution upon Cation Exchange Equilibrium

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    Ion exchange equilibria in batch systems have been examined to see how the distribution of ions between the ion exchanger and the solution depends on the dilution of the solution. The exchanger was Amberlite IR-120. The following exchanges were studied· K +-H+ Mg++-Ca ++ Ca++ -H+ Ba++ -H+ Ce3 +-H+ and La3 + H+. It has been found that dilution of the system causes the ion of higher affinity to pass into the resin phase. This effect is more pronounced for the exchange of ions of unequal charge than for those of the same charge

    Paramagnetic anisotropic magnetoresistance in thin films of SrRuO3

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    SrRuO3 is an itinerant ferromagnet and in its thin film form when grown on miscut SrTiO3 it has Tc of ~ 150 K and strong uniaxial anisotropy. We measured both the Hall effect and the magnetoresistance (MR) of the films as a function of the angle between the applied field and the normal to the films at temperatures above Tc. We extracted the extraordinary Hall effect that is proportional to the perpendicular component of the magnetization and thus the MR for each angle of the applied field could be correlated with the magnitude and orientation of the induced magnetization. We successfully fit the MR data with a second order magnetization expansion, which indicates large anisotropic MR in the paramagnetic state. The extremum values of resistivity are not obtained for currents parallel or perpendicular to the magnetization, probably due to the crystal symmetry.Comment: 3 pages, 3 figure

    Studi Gaya Desain Posmodern pada Interior Food Court Galaxy Mall di Surabaya

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    A food court is an important public facilty in a shopping centre. Apart from its generally large capacity and variety of cuisine served, the design of most foodcourts are also generally attractive.Their interior designs are able to affect the atmoshphere and mood of visitors.Many foodcourts in today's malls adopt the postmodern style in their design, for instance, the Galaxy Mall in Surabaya, which will be the object for case study in this research. The objective of this research is to investigate the implementation of the Post modern style in the interior elements of the food court that will be discussed in detail. The research findings show that the use of Post modern style can be seen in the spatial arrangement, interior elements such as floors, walls and ceilings, furnitures as well as decorative elements such as colour and material. All these elements adopted the Post Modern style in terms of ideology, concept, aim as well as design methodology. The concept of Contradiction has been applied in the two areas of the food court

    Construction of Self-Dual Integral Normal Bases in Abelian Extensions of Finite and Local Fields

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    Let F/EF/E be a finite Galois extension of fields with abelian Galois group Γ\Gamma. A self-dual normal basis for F/EF/E is a normal basis with the additional property that TrF/E(g(x),h(x))=δg,hTr_{F/E}(g(x),h(x))=\delta_{g,h} for g,hΓg,h\in\Gamma. Bayer-Fluckiger and Lenstra have shown that when char(E)2char(E)\neq 2, then FF admits a self-dual normal basis if and only if [F:E][F:E] is odd. If F/EF/E is an extension of finite fields and char(E)=2char(E)=2, then FF admits a self-dual normal basis if and only if the exponent of Γ\Gamma is not divisible by 44. In this paper we construct self-dual normal basis generators for finite extensions of finite fields whenever they exist. Now let KK be a finite extension of \Q_p, let L/KL/K be a finite abelian Galois extension of odd degree and let \bo_L be the valuation ring of LL. We define AL/KA_{L/K} to be the unique fractional \bo_L-ideal with square equal to the inverse different of L/KL/K. It is known that a self-dual integral normal basis exists for AL/KA_{L/K} if and only if L/KL/K is weakly ramified. Assuming p2p\neq 2, we construct such bases whenever they exist
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