12,811 research outputs found

    Design and construction of a new Drosophila species, D.synthetica, by synthetic regulatory evolution

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    Here, I merge the principles of synthetic biology^1,2^ and regulatory evolution^3-11^ to create a new species^12-15^ with a minimal set of known elements. Using preexisting transgenes and recessive mutations of Drosophila melanogaster, a transgenic population arises with small eyes and a different venation pattern that fulfills the criteria of a new species according to Mayr's "Biological Species Concept"^7,10^. The genetic circuit entails the loss of a non-essential transcription factor and the introduction of cryptic enhancers. Subsequent activation of those enhancers causes hybrid lethality. The transition from "transgenic organisms" towards "synthetic species", such as Drosophila synthetica, constitutes a safety mechanism to avoid hybridization with wild type populations and preserve natural biodiversity^16-18^. Drosophila synthetica is the first transgenic organism that cannot hybridize with the original wild type population but remains fertile when crossed with other transgenic animals

    A war-prone tribe migrated out of Africa to populate the world.

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    Of the tribal hunter gatherers still in existence today, some lead lives of great violence, whereas other groups live in societies with no warfare and very little murder^1,2,3,4,5^. Here I find that hunter gatherers that belong to mitochondrial haplotypes L0, L1 and L2 do not have a culture of ritualized fights. In contrast to this, almost all L3 derived hunter gatherers have a more belligerent culture that includes ritualized fights such as wrestling, stick fights or headhunting expeditions. This appears to be independent of their environment, because ritualized fights occur in all climates, from the tropics to the arctic. There is also a correlation between mitochondrial haplotypes and warfare propensity or the use of murder and suicide to resolve conflicts. This, in the light of the “recent out of Africa” hypothesis”^6,7^, suggests that the tribe that left Africa 80.000 years ago performed ritualized fights. In contrast to the more pacific tradition of non-L3 foragers, it may also have had a tendency towards combat. The data implicate that the entire human population outside Africa is descended from only two closely related sub-branches of L3 that practiced ritual fighting and probably had a higher propensity towards warfare and the use of murder for conflict resolution. This may have crucially influenced the subsequent history of the world

    Revisitando un topos: Algunas notas sobre el bandolerismo lusitano (y el imperium de Roma)

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    Se presenta una reflexión sobre el llamado “bandolerismo lusitano”, arraigado tópico en la historiografía antigua sobre el Occidente de Iberia y su legado moderno, a partir de la relectura crítica de las fuentes clásicas y la contextualización del mundo lusitano meridional en el horizonte del imperialismo romano del siglo II a.C. La propuesta pretende confrontar el discurso retórico del narrador romano con el pragmatismo de una hegemonía en disputa sobre un espacio de frontera; entendida ésta en su doble dimensión territorial y mentalA reflection on the so-called “Lusitanian banditry”, a rooted topic of western Iberia in the ancient historiography and its modern legacy, is presented on the basis of a critical (re)reading of the classical sources together with the contextualization of the southern Lusitanian world within the horizon of the 2nd century B.C. Roman imperialism. The proposal aims to face the rhetorical discourse of the Roman narrator with the pragmatism of a competed hegemony into a frontier area; being understood the latter one in its double dimension, territorial and menta

    ¿Qué tenés en la cabeza? Los contornos de la ideología y las identidades políticas

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    Fil: Moreno, José Eduardo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales (UNLP-CONICET); Argentina

    Estabilidade do gerador síncrono com reguladores via método direto de lyapunov

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    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica

    On Some Unifications Arising from the MIMO Rician Shadowed Model

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    This paper shows that the proposed Rician shadowed model for multi-antenna communications allows for the unification of a wide set of models, both for multiple-input multiple-output (MIMO) and single- input single-output (SISO) communications. The MIMO Rayleigh and MIMO Rician can be deduced from the MIMO Rician shadowed, and so their SISO counterparts. Other more general SISO models, besides the Rician shadowed, are included in the model, such as the κ-μ, and its recent generalization, the κ-μ shadowed model. Moreover, the SISO η-μ and Nakagami-q models are also included in the MIMO Rician shadowed model. The literature already presents the probability density function (pdf) of the Rician shadowed Gram channel matrix in terms of the well-known gamma- Wishart distribution. We here derive its moment generating function in a tractable form. Closed- form expressions for the cumulative distribution function and the pdf of the maximum eigenvalue are also carried out.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Nonlinear quantum optics in the (ultra)strong light-matter coupling

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    The propagation of NN photons in one dimensional waveguides coupled to MM qubits is discussed, both in the strong and ultrastrong qubit-waveguide coupling. Special emphasis is placed on the characterisation of the nonlinear response and its linear limit for the scattered photons as a function of NN, MM, qubit inter distance and light-matter coupling. The quantum evolution is numerically solved via the Matrix Product States technique. Both the time evolution for the field and qubits is computed. The nonlinear character (as a function of N/MN/M) depends on the computed observable. While perfect reflection is obtained for N/M1N/M \cong 1, photon-photon correlations are still resolved for ratios N/M=2/20N/M= 2/20. Inter-qubit distance enhances the nonlinear response. Moving to the ultrastrong coupling regime, we observe that inelastic processes are \emph{robust} against the number of qubits and that the qubit-qubit interaction mediated by the photons is qualitatively modified. The theory developed in this work modelises experiments in circuit QED, photonic crystals and dielectric waveguides.Comment: Comments are wellcom
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