1,969 research outputs found

    Protoplanetary disks in the hostile environment of Carina

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    We report the first direct imaging of protoplanetary disks in the star-forming region of Carina, the most distant massive cluster in which disks have been imaged. Using the Atacama Large Millimeter/sub-millimeter Array (ALMA), the disks are observed around two young stellar objects (YSOs) that are embedded inside evaporating gaseous globules and exhibit jet activity. The disks have an average radius of 60 au and total masses of 30 and 50 MJup{M}_{\mathrm{Jup}}. Given the measured masses, the minimum timescale required for planet formation (~1–2 Myr) and the average age of the Carina population (~1–4 Myr), it is plausible that young planets are present or their formation is currently ongoing in these disks. The non-detection of millimeter emission above the 4σ threshold (7MJup\sim 7{M}_{\mathrm{Jup}}) in the core of the massive cluster Trumpler 14, an area containing previously identified proplyd candidates, suggests evidence for rapid photo-evaporative disk destruction in the cluster's harsh radiation field. This would prevent the formation of giant gas planets in disks located in the cores of Carina's dense subclusters, whereas the majority of YSO disks in the wider Carina region remain unaffected by external photoevaporation

    Effective theories of connections and curvature: abelian case

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    We introduce a notion of measuring scales for quantum abelian gauge systems. At each measuring scale a finite dimensional affine space stores information about the evaluation of the curvature on a discrete family of surfaces. Affine maps from the spaces assigned to finer scales to those assigned to coarser scales play the role of coarse graining maps. This structure induces a continuum limit space which contains information regarding curvature evaluation on all piecewise linear surfaces with boundary. The evaluation of holonomies along loops is also encoded in the spaces introduced here; thus, our framework is closely related to loop quantization and it allows us to discuss effective theories in a sensible way. We develop basic elements of measure theory on the introduced spaces which are essential for the applicability of the framework to the construction of quantum abelian gauge theories.Comment: 39 page

    Directed current due to broken time-space symmetry

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    We consider the classical dynamics of a particle in a one-dimensional space-periodic potential U(X) = U(X+2\pi) under the influence of a time-periodic space-homogeneous external field E(t)=E(t+T). If E(t) is neither symmetric function of t nor antisymmetric under time shifts E(t±T/2)E(t)E(t \pm T/2) \neq -E(t), an ensemble of trajectories with zero current at t=0 yields a nonzero finite current as tt\to \infty. We explain this effect using symmetry considerations and perturbation theory. Finally we add dissipation (friction) and demonstrate that the resulting set of attractors keeps the broken symmetry property in the basins of attraction and leads to directed currents as well.Comment: 2 figure

    Epitome de la vida y muerte de la Reyna Doña Berenguela, primogenita del Rey Don Alonso de Castilla, aclamado el noble

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    Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Errores de pag., de p. 79 retrocede a p. 70Grab. xil. de la InmaculadaContiene: Tratado apologetico en defensa de mayoria de la Reina Doña Bereguela y el derecho q tuvo a los reynos de Castilla, p. 169 -23

    Mirror symmetry breaking through an internal degree of freedom leading to directional motion

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    We analyze here the minimal conditions for directional motion (net flow in phase space) of a molecular motor placed on a mirror-symmetric environment and driven by a center-symmetric and time-periodic force field. The complete characterization of the deterministic limit of the dissipative dynamics of several realizations of this minimal model, reveals a complex structure in the phase diagram in parameter space, with intertwined regions of pinning (closed orbits) and directional motion. This demonstrates that the mirror-symmetry breaking which is needed for directional motion to occur, can operate through an internal degree of freedom coupled to the translational one.Comment: Accepted for publication in Phys. Rev.

    Multi-scale coordination of distinctive movement patterns during embodied interaction between adults with high-functioning autism and neurotypicals

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    Funding We acknowledge financial support from DGAPA-PAPIIT projects of the Universidad Nacional Autónoma de México: IA105017 (RF and LZ-F) and IA104717 (TF), Consejo Nacional de Ciencia y Tecnología (CONACyT) projects 167441 (RF and LZ-F), the scholarship 638215 to LZ-F granted by the CONACyT, the Newton Advanced Fellowship awarded to RF by the Academy of Medical Sciences, through the UK Government’s Newton, and the Marie Curie Intra-European Fellowship “SOCIAL BRAIN” awarded to BT. Acknowledgments We thank Charles Lenay and Dominique Aubert from the Université de Technologie de Compiègne for making the TACTOS hardware and software available to the University Hospital Cologne, and for providing technical support. LZ-F would like to specially thank Jesús Naveja and Lilia Fonseca for interesting discussions. SUPPLEMENTARY MATERIAL The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyg.2018.02760/full#supplementary-materialPeer reviewedPublisher PD
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