5,290 research outputs found

    Enargite by XPS

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    X-ray photoelectron spectroscopy was used for characterizing the enargite surface. Freshly cleaved samples were analyzed at liquid nitrogen temperature. Enargite is a copper arsenic sulfide of formula Cu3AsS4; it is used as a minor ore of copper. Enargite is a potential source of arsenic and may create environmental problems through the release of toxic elements upon oxidatio

    Fiscal sustainability and policy implications for the euro area

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    In this paper we examine the sustainability of euro area public finances against the backdrop of population ageing. We critically assess the widely used projections of the Working Group on Ageing Populations (AWG) of the EU's Economic Policy Committee and argue that ageing costs may be higher than projected in the AWG reference scenario. Taking into account adjusted headline estimates for ageing costs, largely based upon the sensitivity analysis carried out by the AWG, we consider alternative indicators to quantify sustainability gaps for euro area countries. With respect to the policy implications, we assess the appropriateness of different budgetary strategies to restore fiscal sustainability taking into account intergenerational equity. Our stylised analysis based upon the lifetime contribution to the government's primary balance of different generations suggests that an important degree of pre-funding of the ageing costs is necessary to avoid shifting the burden of adjustment in a disproportionate way to future generations. For many euro area countries this implies that the medium-term targets defined in the context of the revised stability and growth pact would ideally need to be revised upwards to significant surpluses. --population ageing,fiscal sustainability,generational accounting,medium-term objectives for fiscal policy

    Grinding and fine finishing of future automotive powertrain components

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    The automotive industry is undergoing a major transformation driven by regulations and a fast-paced electrification. A critical analysis of technological trends and associated requirements for major automotive powertrain components is carried out in close collaboration with industry – covering the perspectives of OEMs, suppliers, and machine builders. The main focus is to review the state of the art with regard to grinding, dressing, texturing and fine-finishing technologies. A survey of research papers and patents is accompanied by case studies that provide further insights into the production value chain. Finally, key industrial and research challenges are summarized

    Simple Model for the Variation of Superfluid Density with Zn Concentration in YBCO

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    We describe a simple model for calculating the zero-temperature superfluid density of Zn-doped YBa_2Cu_3O_{7-\delta} as a function of the fraction x of in-plane Cu atoms which are replaced by Zn. The basis of the calculation is a ``Swiss cheese'' picture of a single CuO_2 layer, in which a substitutional Zn impurity creates a normal region of area πξab2\pi\xi_{ab}^2 around it as originally suggested by Nachumi et al. Here ξab\xi_{ab} is the zero-temperature in-plane coherence length at x = 0. We use this picture to calculate the variation of the in-plane superfluid density with x at temperature T = 0, using both a numerical approach and an analytical approximation. For δ=0.37\delta = 0.37, if we use the value ξab\xi_{ab} = 18.3 angstrom, we find that the in-plane superfluid decreases with increasing x and vanishes near xc=0.01x_c = 0.01 in the analytical approximation, and near xc=0.014x_c = 0.014 in the numerical approach. xcx_c is quite sensitive to ξab\xi_{ab}, whose value is not widely agreed upon. The model also predicts a peak in the real part of the conductivity, Reσe(ω,x)\sigma_e(\omega, x), at concentrations xxcx \sim x_c, and low frequencies, and a variation of critical current density with x of the form Jc(x)nS,e(x)7/4J_c(x) \propto n_{S,e}(x)^{7/4} near percolation, where nS,e(x)n_{S,e}(x) is the in-plane superfluid density.Comment: 19 pages including 6 figures, submitted to Physica

    Magnetic resonance peak and nonmagnetic impurities

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    Nonmagnetic Zn impurities are known to strongly suppress superconductivity. We review their effects on the spin excitation spectrum in YBa2Cu3O7\rm YBa_2Cu_3O_{7}, as investigated by inelastic neutron scattering measurements.Comment: Proceedings of Mato Advanced Research Workshop BLED 2000. To appear in Nato Science Series: B Physic

    Reliability of common mouse behavioural tests of anxiety: A systematic review and meta-analysis on the effects of anxiolytics.

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    The validity of widely used rodent behavioural tests of anxiety has been questioned, as they often fail to produce consistent results across independent replicate studies. In this study, we assessed the sensitivity of common behavioural tests of anxiety in mice to detect anxiolytic effects of drugs prescribed to treat anxiety in humans. We conducted a pre-registered systematic review of 814 studies reporting effects of 25 anxiolytic compounds using common behavioural tests for anxiety. Meta-analyses of effect sizes of treatments showed that only two out of 17 commonly used test measures reliably detected effects of anxiolytic compounds. We report considerable between-study variation in size and even direction of effects of most anxiolytics on most outcome variables. Our findings indicate a general lack of sensitivity of those behavioural tests and cast serious doubt on both construct and predictive validity of most of these tests. In view of scientifically valid and ethically responsible research, we call for a revision of behavioural tests of anxiety in mice and the development of more predictive tests

    Educar para a Sustentabilidade pela Redescoberta de Gaia: Relato de Caso sobre a Realização de Oficinas de Formação Pedagógica com Estudantes do Ensino Médio – Curso Normal, em Encruzilhada do Sul, RS, Brasil

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    Pressupondo-se a necessidade de uma educação construcionista, pautada no desenvolvimento de uma pedagogia desenvolvida em projetos, incentivando descobertas e reconstruções do conhecimento, o presente trabalho buscou avaliar a eficácia de oficinas de formação pedagógica realizadas em instituto educacional do município de Encruzilhada do Sul - RS, verificando, a partir de encontros síncronos e aplicação de questionários, as visões das estudantes sobre temáticas como Sustentabilidade, Biodiversidade, Responsabilidade Individual e Protagonismo Docente. O estudo foi realizado durante a realização do Estágio Supervisionado em Biologia II, constante do currículo do curso de Ciências Biológicas - Licenciatura, da Universidade de Santa Cruz do Sul - UNISC, entre os meses de outubro e dezembro de 2020. Dentre os resultados obtidos, destaca-se a obtenção de respostas qualificadas, as quais foram analisadas de acordo com as premissas da Educação Ambiental Crítica, justificando-se a importância de tal abordagem para a compreensão do mundo contemporâneo

    Effect of non-abrupt doping and interfacial profiles on the carrier sheet density in one-side modulation-doped GaN/AlGaN quantum wells

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    The results of an accurate theoretical study on the effects of non-abrupt doping and interfacial profiles on the electron sheet density in one-side modulation-doped wurtzite GaN/AlGaN single quantum wells at low temperatures are presented. We solve coupled Schr¨odinger and Poisson equations self-consistently via the finite difference method. By employing a proper discretization on a nonuniform grid and taking into account the strong piezoelectric and spontaneous polarization fields exhibited by the wurtzite III-nitride heterostructures, a substantial increase in the 2DEG density is predicted with the increase of the donor diffusion length and the reduction of the spacer thickness

    Checklist of chelonians from the upper madeira river and the lower Madeira–Purus interfluvium (Brazilian Amazon), including a range expansion for Podocnemis sextuberculata Cornalia, 1849

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    We present data on occurrence of chelonians for the Madeira River (southwestern Amazon, Brazil). Sampling was undertaken along the BR-319 Highway in the Madeira-Purus interfluvium and along a 125‑km stretch of the upper Madeira River. Findings were contrasted with a checklist of species expected to occur in the region according to current distribution maps, and with literature data for the Madeira subbasin. Out of 12 expected species, we recorded five in the Madeira- Purus interfluvium (three other species were registered by other recent voucher-based studies in the region), and eight species in the upper Madeira region. Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 occurred below and inbetween the upper Madeira rapids. Podocnemis sextuberculata Cornalia, 1849 had its range extended by over 700 km, but may be limited upriver by the rapids. Mesoclemmys gibba (Schweigger, 1812) and M. raniceps Gray, 1855 occurred sympatrically along the river. Chelonian diversity along the lower and upper Madeira appears to be complementary. © 2016 Check List and Authors

    Report and preliminary results of SONNE cruise SO175, Miami - Bremerhaven, 12.11 - 30.12.2003 : (GAP, Gibraltar Arc Processes)

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    Expedition SO175 using FS Sonne aimed for a multidisciplinerary geoscientific approach with an international group of researchers. Methods covered the entire span from geophysical data acquisition (seafloor mapping, echography, seismic reflection), sediment coring at sites of active fluid venting, in situ heat flow measurements across the entire length of the Gibraltar thrust wedge, the deformation front, landslide bodies, and mud volcanoes, and finally the deployment of a long-term pore pressure probe. Video-supported operations helped to identify fluid vent sites, regions with tectonic activity, and other attractive high priority targets. Qualitative and quantitative examinations took place on board and are continued on land with respect to pore pressure variation, geomicrobiology, sediment- and fluid mobilization, geochemical processes, faunal assemblages (e.g. cold water corals), and gas hydrates (flammable methane-ice-crystals). Main focus of the expedition has been a better understanding of interaction between dynamic processes in a seismically active region region with slow plate convergence. In the context of earthquake nucleation and subduction zone processes, the SO175 research programme had a variety of goals, such as: • To test the frictional behaviour of the abyssal plain sediments. • To explore the temperature field of the 1755 thrust earthquake event via heat flow measurements. • To assess the role of fluid venting and gas hydrate processes control slope stability and mud volcanic activity along the Iberian continental margin. • To measure isotope geochemistry of pore waters and carbonates of deep fluids. • To quantify microbial activity in Gibraltar wedge sediments. • To test whether microseismicity in the area corresponds to in situ pore pressure changes. • To find out if enhanced heat flow max be indicative of active subduction. Initial tentative results during the cruise suggest that there is a component of active thrusting at the base of the wedge, as attested by heat flow data. Based on mostly geochemical evidence, mud volcanism was found less active than previously assumed. Highlights from post-cruise research include the successful deployment of the long-term station and high frictional resistance of all incoming sediment on the three abyssal plains
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