36 research outputs found
Quantifying Quantum Correlations in Fermionic Systems using Witness Operators
We present a method to quantify quantum correlations in arbitrary systems of
indistinguishable fermions using witness operators. The method associates the
problem of finding the optimal entan- glement witness of a state with a class
of problems known as semidefinite programs (SDPs), which can be solved
efficiently with arbitrary accuracy. Based on these optimal witnesses, we
introduce a measure of quantum correlations which has an interpretation
analogous to the Generalized Robust- ness of entanglement. We also extend the
notion of quantum discord to the case of indistinguishable fermions, and
propose a geometric quantifier, which is compared to our entanglement measure.
Our numerical results show a remarkable equivalence between the proposed
Generalized Robustness and the Schliemann concurrence, which are equal for pure
states. For mixed states, the Schliemann con- currence presents itself as an
upper bound for the Generalized Robustness. The quantum discord is also found
to be an upper bound for the entanglement.Comment: 7 pages, 6 figures, Accepted for publication in Quantum Information
Processin
Discovery of a single male Aedes aegypti (L.) in Merseyside, England
© The Author(s). 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The file attached is the published (publishers PDF) version of the article
Efeito de fertilizantes nitrogenados na produtividade de melĂŁo
Em Petrolina, PE, foi realizado um estudo com a cultura do melĂŁo (Cucumis melo L.), Valenciano Amarelo, num Latossolo, para avaliar o efeito de fontes de fertilizantes nitrogenados e de suas combinaçÔes. O delineamento experimental foi em blocos casualizados com arranjo em faixa, com quatro repetiçÔes e nove tratamentos englobando a testemunha e os fertilizantes nitrogenados na dose de 80 kg/ha de N, aplicados no solo e, ou, via ĂĄgua de irrigação, por um perĂodo de 42 dias apĂłs a germinação. Esses tratamentos foram: UrĂ©ia e Sulfato de AmĂŽnio isolados; UrĂ©ia (15 dias) + Nitrato de PotĂĄssio (16-42 dias); UrĂ©ia (15 dias) + Sulfato de AmĂŽnio (16-42 dias); UrĂ©ia (30 dias) + Nitrato de PotĂĄssio (31-42 dias); UrĂ©ia (15 dias) + Sulfato de AmĂŽnio (16-30 dias) + Nitrato de PotĂĄssio (31-42 dias). A urĂ©ia aplicada via fertirrigação atĂ© 42 dias proporcionou maior rendimento (31,14 t/ha), embora nĂŁo estatisticamente diferente dos demais tratamentos. A testemunha e o sulfato de amĂŽnio mostraram-se menos produtivos, com rendimentos de 25,06 e 24,65 t/ha, respectivamente. O peso mĂ©dio do fruto variou de 1,63 a 1,84 kg/fruto, e o teor de sĂłlidos solĂșveis totais, de 12,1 a 13,1 ÂșBrix; nĂŁo se verificaram diferenças estatĂsticas
TRY plant trait database â enhanced coverage and open access
Plant traitsâthe morphological, anatomical, physiological, biochemical and phenological characteristics of plantsâdetermine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traitsâalmost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives