Globally coupled maps with asynchronous updating

We analyze a system of globally coupled logistic maps with asynchronous updating. We show that its dynamics differs considerably from that of the synchronous case. For growing values of the coupling intensity, an inverse bifurcation cascade replaces the structure of clusters and ordering in the phase diagram. We present numerical simulations and an analytical description based on an effective single-element dynamics affected by internal fluctuations. Both of them show how global coupling is able to suppress the complexity of the single-element evolution. We find that, in contrast to systems with synchronous update, internal fluctuations satisfy the law of large numbers.Comment: 7 pages, submitted to PR

Imitation dynamics in a game of traffic

We study a model of traffic where drivers adopt different behavioral strategies. These can be cooperative or defective according to a driver abiding or not by a traffic rule. Drivers can change their strategy by imitating the majority, with a rule that depends on the strategies with which they have interacted. These interactions occur at intersections, where vehicles pay a temporal cost according to their strategy. We analyze the conditions under which different strategy compositions represent an advantage in the system velocity. We found that the cooperators' mean speed is higher than the defectors' even when the vehicle density is large. However, defectors can obtain benefits in their mean speed when they are a minority in an essentially cooperative population. The presence of a core of educated drivers, who persist firmly in a cooperative behavior, optimizes the speed in the system, especially for intermediate values of vehicular density and higher temporal costs

Dilatation operator and the Super Yang-Mills duals of open strings on AdS Giant Gravitons

We study the one-loop anomalous dimensions of the Super Yang-Mills dual operators to open strings ending on AdS giant gravitons. AdS giant gravitons have no upper bound for their angular momentum and we represent them by the contraction of scalar fields, carrying the appropriate R-charge, with a totally symmetric tensor. We represent the open string motion along AdS directions by appending to the giant graviton operator a product of fields including covariant derivatives. We derive a bosonic lattice Hamiltonian that describes the mixing of these excited AdS giants operators under the action of the one-loop dilatation operator of N=4 SYM. This Hamiltonian captures several intuitive differences with respect to the case of sphere giant gravitons. A semiclassical analysis of the Hamiltonian allows us to give a geometrical interpretation for the labeling used to describe the fields products appended to the AdS giant operators. It also allows us to show evidence for the existence of continuous bands in the Hamiltonian spectrum.Comment: 28 page

Synchronization learning of coupled chaotic maps

We study the dynamics of an ensemble of globally coupled chaotic logistic maps under the action of a learning algorithm aimed at driving the system from incoherent collective evolution to a state of spontaneous full synchronization. Numerical calculations reveal a sharp transition between regimes of unsuccessful and successful learning as the algorithm stiffness grows. In the regime of successful learning, an optimal value of the stiffness is found for which the learning time is minimal

Strings in AdS_4 x CP^3, Wilson loops in N=6 super Chern-Simons-matter and Bremsstrahlung functions

We find 1/6 BPS string configurations in AdS_4 x CP^3, which we identify as the duals of certain 1/6 BPS circular Wilson loops in N=6 super Chern-Simons-matter gauge theory. We use our results to verify -in the strong coupling limit- a proposal made in arXiv:1402.4128 for a relation between the expectation value of these Wilson loops and the Bremsstrahlung function from deforming 1/2 BPS Wilson lines with a cusp. We also derive an analogous relation between the expectation value of some particular 1/12 BPS Wilson loops and the Bremsstrahlung function from deforming 1/6 BPS Wilson lines with an internal space cusp.Comment: 25 pages, 1 figures; v2 author ordering correcte

Semiclassical partition function for strings dual to Wilson loops with small cusps in ABJM

We compute the 1-loop partition function for strings in $AdS_4\times\mathbb{CP}^3$, whose worldsheets end along a line with small cusp angles in the boundary of AdS. We obtain these 1-loop results in terms of the vacuum energy for on-shell modes. Our results verify the proposal by Lewkowycz and Maldacena in arXiv:1312.5682 for the exact Bremsstrahlung function up to the next to leading order in the strong coupling expansion. The agreement is observed for cusps distorting either the 1/2 BPS or the 1/6 BPS Wilson line.Comment: 28 page

Associations of maternal and adolescent religiosity and spirituality with adolescent alcohol use in Chile: implications for social work practice

To inform social work practice with adolescents who may consume alcohol, we examined if alcohol use among Chilean adolescents varied as a function of their mothers’ and their own religiosity and spirituality. Data were from 787 Chilean adolescents and their mothers. Adolescent spirituality was a protective factor against more deleterious alcohol use. Parental monitoring and alcohol using opportunities mediated the associations. The practice of religious behaviors by themselves without meaningful faith were not associated with alcohol use among adolescents. Implications for social work practice are discussed.This research was funded by the US National Institute on Drug Abuse (R01 02118). The project also received support from the Curtis Research and Training Center of the School of Social Work at the University of Michigan and from the University of Michigan Substance Abuse Research Center Ruth L. Kirschstein National Research Service Award T32 DA007267. (R01 02118 - US National Institute on Drug Abuse; Curtis Research and Training Center of the School of Social Work at the University of Michigan; T32 DA007267 - University of Michigan Substance Abuse Research Center Ruth L. Kirschstein National Research Service

Half-mass radii for ~7,000 galaxies at 1.0 < z < 2.5: most of the evolution in the mass-size relation is due to color gradients

Radial mass-to-light ratio gradients cause the half-mass and half-light radii of galaxies to differ, potentially biasing studies that use half-light radii. Here we present the largest catalog to date of galaxy half-mass radii at z > 1: 7,006 galaxies in the CANDELS fields at 1.0 < z < 2.5. The sample includes both star-forming and quiescent galaxies with stellar masses 9.0 < log(M_* / M_\odot) < 11.5. We test three methods for calculating half-mass radii from multi-band PSF-matched HST imaging: two based on spatially-resolved SED modeling, and one that uses a rest-frame color profile. All three methods agree, with scatter <~0.3 dex. In agreement with previous studies, most galaxies in our sample have negative color gradients (the centers are redder than the outskirts, and r_e,mass < r_e,light). We find that color gradient strength has significant trends with increasing stellar mass, half-light radius, U-V color, and stellar mass surface density. These trends have not been seen before at z>1. Furthermore, color gradients of star-forming and quiescent galaxies show a similar redshift evolution: they are flat at z>~2, then steeply decrease as redshift decreases. This affects the galaxy mass-size relation. The normalizations of the star-forming and quiescent r_mass-M_* relations are 10-40% smaller than the corresponding r_light-M_* relations; the slopes are ~0.1-0.3 dex shallower. Finally, the half-mass radii of star-forming and quiescent galaxies at M_* = 10^{10.5}M_\odot only grow by ~1%$ and ~8% between z~2.25 and z~1.25. This is significantly less than the ~37% and ~47% size increases found when using the half-light radius.Comment: 18 pages, 10 figures. Accepted to Ap

Optical Photometry and Spectroscopy of the Suspected Cool Algol AV Delphini: Determination of the Physical Properties

We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del ( period = 3:85 days) conducted over six observing seasons. A detailed radial velocity and light-curve analysis of the optical data shows the system to be most likely semidetached, with the less massive and cooler star filling its Roche lobe. The system is probably a member of the rare class of ‘‘cool Algol’’ systems, which are distinguished from the ‘‘classical’’ Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the spectroscopic and photometric analyses, we derive accurate absolute masses for the components of M1 = 1.453 + 0.028 M and M2 = 0.705 + 0.014 M and radii of R1 = 2.632 + 0.030 R and R2 = 4.233 + 0.060 R, as well as effective temperatures of 6000 + 200 and 4275 + 150 K for the primary and secondary, respectively. There are no obvious signs of activity (spottedness) in the optical light curve of the binary