7,807 research outputs found

    Nuevos datos acerca de la explotación de la vid en el eneolítico español

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    Hallazgos de semillas de uva en el prado de Jumilla (Murcia), junto con otros datos de diversos yacimientos prehistóricos, aportan indicios de la explotación de "vitis vinifera". L. en España desde el tercer milenio. Se presentan estos datos en el contexto de la problemática de los orígenes de la viticultura en la Europa mediterránea

    Towards Universal Topological Quantum Computation in the ν=5/2\nu=5/2 Fractional Quantum Hall State

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    The Pfaffian state, which may describe the quantized Hall plateau observed at Landau level filling fraction ν=5/2\nu = 5/2, can support topologically-protected qubits with extremely low error rates. Braiding operations also allow perfect implementation of certain unitary transformations of these qubits. However, in the case of the Pfaffian state, this set of unitary operations is not quite sufficient for universal quantum computation (i.e. is not dense in the unitary group). If some topologically unprotected operations are also used, then the Pfaffian state supports universal quantum computation, albeit with some operations which require error correction. On the other hand, if certain topology-changing operations can be implemented, then fully topologically-protected universal quantum computation is possible. In order to accomplish this, it is necessary to measure the interference between quasiparticle trajectories which encircle other moving trajectories in a time-dependent Hall droplet geometry.Comment: A related paper, cond-mat/0512072, explains the topological issues in greater detail. It may help the reader to look at this alternate presentation if confused about any poin

    Determining the superconducting gap structure in Sr2RuO4 from sound attenuation studies below Tc

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    This work presents a quantitative theoretical study of the sound attenuation in the unconventional multiband superconductor Sr2RuO4 below the superconducting transition temperature Tc. Sound attenuation in this material is shown to have the remarkable property of being able to identify different nodal structures on different bands. The nodal structures on the \gamma band on the one hand, and on the \alpha and \beta bands on the other, are both found to be characterized by the existence of point nodes, but are significantly different in their quantitative aspects.Comment: 7 pages, REVTe

    The Crucial Role of Error Correlation for Uncertainty Modeling of CFD-Based Aerodynamics Increments

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    The Ares I ascent aerodynamics database for Design Cycle 3 (DAC-3) was built from wind-tunnel test results and CFD solutions. The wind tunnel results were used to build the baseline response surfaces for wind-tunnel Reynolds numbers at power-off conditions. The CFD solutions were used to build increments to account for Reynolds number effects. We calculate the validation errors for the primary CFD code results at wind tunnel Reynolds number power-off conditions and would like to be able to use those errors to predict the validation errors for the CFD increments. However, the validation errors are large compared to the increments. We suggest a way forward that is consistent with common practice in wind tunnel testing which is to assume that systematic errors in the measurement process and/or the environment will subtract out when increments are calculated, thus making increments more reliable with smaller uncertainty than absolute values of the aerodynamic coefficients. A similar practice has arisen for the use of CFD to generate aerodynamic database increments. The basis of this practice is the assumption of strong correlation of the systematic errors inherent in each of the results used to generate an increment. The assumption of strong correlation is the inferential link between the observed validation uncertainties at wind-tunnel Reynolds numbers and the uncertainties to be predicted for flight. In this paper, we suggest a way to estimate the correlation coefficient and demonstrate the approach using code-to-code differences that were obtained for quality control purposes during the Ares I CFD campaign. Finally, since we can expect the increments to be relatively small compared to the baseline response surface and to be typically of the order of the baseline uncertainty, we find that it is necessary to be able to show that the correlation coefficients are close to unity to avoid overinflating the overall database uncertainty with the addition of the increments

    Racing with a purpose:Sustainability in Formula E

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    This study examined the seasonal sustainability reporting of Formula E for its content, variation, and linearity. Formula E was chosen since it was built as a sustainable sport enterprise rather than one which integrated sustainability into existing operations and for the accessibility of its annual sustainability reports. Using an exploratory approach for content and variation, and the Green Waves of sport sustainability for linearity, eight seasons of sustainability reports from Formula E were collected and examined via content analysis. Findings revealed the major content areas for Formula E concerned event management, car design, and community engagement with these initiatives classified as internal or external efforts. Reports were inconsistent in their structure, language, scope, and focus. The Green Waves suggest that while some efforts progress, others may regress according to strategy or the initiative’s life cycle. Formula E is progressing overall in their sustainability efforts, but exemplifies the lack of an end point to sustainability efforts. It is suggested that better coordination could yield higher strategic success and recognition

    Studying the spatial distribution of interstellar dust

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    The spacial distribution of interstellar dust reflects both interstellar dynamics and the processes which form and destroy dust in the interstellar medium (ISM). The IRAS survey, because of its high sensitivity to thermal emission from dust in the IR, provides new approaches to determining the spatial distribution of dust. The initial results are reported of an attempt to use the IRAS data to probe the spatial distribution of dust - by searching for thermal emission from dust in the vicinity of bright stars. These results show that this technique (which relies on finding IR emission associated with randomly selected stars) can ultimately be used to study the distribution of dust in the ISM. The density of the cloud producing the IR emission may be derived by assuming that the dust is at its projected distance from the star and that the heating is due to the star's (known) radiation field. The heating radiation is folded into a grain model, and the number of emitting grains adjusted to reproduce the observed energy distribution. It is noted that this technique is capable in principle of detecting dust densities much lower than those typical of the cirrus clouds

    T-cell Apoptosis in Human Glioblastoma Multiforme: Implications for Immunotherapy

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    We used immunohistochemistry and flow cytometry to assess apoptosis in human glioblastoma multiforme (GBM). Our immunohistochemical study revealed apoptosis of glioma cells expressing glial fibrillary acidic protein and of CD3+ T cells infiltrating GBM. To quantify and phenotype the apoptotic T cells, we performed flow cytometry on lymphocytes separated from GBM. The cells were stained with annexin-V-FLUOS/propidium iodide to identify apoptosis. We found that high proportions of both the CD4+ and CD8+ T cells were apoptotic. In particular, we found that T cells expressing Fas ligand (Fas-L, CD95L) were eight times more vulnerable to apoptosis than those not expressing Fas-L, which suggests that the T-cell apoptosis is induced by overactivation of the T-cell receptor, possibly in the absence of appropriate costimulation. Our results have implications for the design of immunotherapies for GBM
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