Statistical learning is not error-driven

Prediction errors have a prominent role in many forms of learning. For example, in reinforcement learning agents learn by updating the association between states and outcomes as a function of the prediction error elicited by the event. An empirical hallmark of such error-driven learning is Kamin blocking, whereby the association between a stimulus and outcome is only learnt when the outcome is not already fully predicted by another stimulus. It remains debated however to which extent error-driven computations underlie learning of automatically formed associations as in statistical learning. Here we asked whether the automatic and incidental learning of the statistical structure of the environment is error-driven, like reinforcement learning, or instead does not rely on prediction errors for learning associations. We addressed this issue in a series of Kamin blocking studies. In three consecutive experiments, we observed robust incidental statistical learning of temporal associations among pairs of images, but no evidence of blocking. Our results suggest that statistical learning is not error-driven but may rather follow the principles of basic Hebbian associative learning

Orchestrating Tuple-based Languages

The World Wide Web can be thought of as a global computing architecture supporting the deployment of distributed networked applications. Currently, such applications can be programmed by resorting mainly to two distinct paradigms: one devised for orchestrating distributed services, and the other designed for coordinating distributed (possibly mobile) agents. In this paper, the issue of designing a pro- gramming language aiming at reconciling orchestration and coordination is investigated. Taking as starting point the orchestration calculus Orc and the tuple-based coordination language Klaim, a new formalism is introduced combining concepts and primitives of the original calculi. To demonstrate feasibility and effectiveness of the proposed approach, a prototype implementation of the new formalism is described and it is then used to tackle a case study dealing with a simplified but realistic electronic marketplace, where a number of on-line stores allow client applications to access information about their goods and to place orders

Transmisión intergeneracional de la pobreza en Uruguay

El deterioro de los niveles de desigualdad y el empeoramiento de los niveles de pobreza que se registraron en Uruguay durante la crisis de comienzos del siglo XXI, tuvieron una especial repercusión en la infancia y la juventud, haciendo más vulnerable el futuro desempeño socioeconómico de las nuevas generaciones. El presente trabajo pretende ahondar en la existencia y extensión de la transmisión intergeneracional de la pobreza (TIP) en Uruguay. La ausencia de datos de panel impide la utilización de algunas de las metodologías más difundidas, como la correlación intergeneracional de ingresos, por lo cual se opta por centrar el análisis en la correlación intergeneracional educativa, mediante la utilización de la Encuesta Continua de Hogares del año 2005. Los resultados comprueban la existencia de correlación intergeneracional educativa en Uruguay, que se ubica por debajo de la registrada en la mayoría de los países de América Latina, y por encima de la registrada en los países más desarrollados. Para ahondar en los determinantes de la TIP se ha estimado un modelo de selección discreta que permite explicar la probabilidad de los jóvenes de terminar la enseñanza secundaria (umbral que permite situarse fuera de la situación de pobreza) en función de una serie de variables vinculadas con el entorno familiar. Se comprueba así la significativa importancia de la educación de los padres en la explicación de los resultados de los hijos, respaldando los enfoques teóricos del capital humano y de la transmisión de habilidades. El análisis también evidencia el efecto negativo de un mayor número de hermanos en la familia, comprobando la importancia del enfoque de cantidad calidad de Becker. Finalmente, los resultados permiten entrever la importancia de otros mecanismos de la TIP como la segregación residencial, el assortative mating y el embarazo adolescente

Interactions between Plasmopara viticola infection and stilbene synthesis in leaves and berries of ten 'Cabernet Sauvignon' clones

Combining the knowledge that Plasmopara viticola causes considerable damages to Vitis vinifera L. worldwide production and that stilbenes have a regulatory influence on Plasmopara viticola - grapevine interaction, this study compares infection time course and stilbenes production in leaves and berries of ten different clones of 'Cabernet Sauvignon'. Following increasing infection rates, different stilbenes were produced and accumulated in leaves and berries of the same clone. Higher absolute values were found in leaves, where trans-resveratrol reaches up to 8 μg g-1 fw and ε-viniferin up to 30 μg g-1 fw while in berries, the values accumulated only up to a maximum of 3 μg g-1 fw of trans-piceid and 1,5 μg g-1 fw ε-viniferin

Ocorrência da sigatoka negra em bananeiras no Estado de São Paulo.

No mês de junho de 2004 foi identificada no Município de Miracatu, SP, sobre as cultivares Galil 7, Galil 18 e Nam. As características típicas do fungo Mycosphaerella fijiensis foram observadas ao microscópio ótico. Esse é o primeiro relato da doença Sigatoka negra no Estado de São Paulo.Comunicação Científica

Raman Topography and Strain Uniformity of Large-Area Epitaxial Graphene

We report results from two-dimensional Raman spectroscopy studies of large-area epitaxial graphene grown on SiC. Our work reveals unexpectedly large variation in Raman peak position across the sample resulting from inhomogeneity in the strain of the graphene film, which we show to be correlated with physical topography by coupling Raman spectroscopy with atomic force microscopy. We report that essentially strain free graphene is possible even for epitaxial graphene.Comment: 10 pages, 3 figure

Mechanical characterization of Ti(C,N)-based cermets fabricated through different colloidal processing routes

In this work the influence of different colloidal processing routes on the mechanical behavior of several Ti(C,N)-based cermets has been studied. The materials were designed with a Ti(C, N) content ranging between 80 and 85 vol %, in a Fe-Ni alloy matrix (with and without carbon addition). Three processing techniques were investigated: (i) Slip Casting (SC), (ii) Slip Casting + Cold Isostatic Pressing (SC+CIP), and (iii) Spray-Dry + Uniaxial Pressing (SDP). Biaxial strength distributions were determined in all samples using the ball-on-three-balls (B3B) method on disc-shaped specimens. Results were interpreted in the framework of Weibull theory. The characteristic strength ranged between 1090 MPa and 1870 MPa. A fractographic analysis performed on selected specimens showed different critical flaws, depending on the processing route, related to the composition and porosity level in each case. Single Edge V-Notched Beam (SEVNB) specimens fabricated with SDP were tested under 4-point-bending, in order to identify the effect of Fe-Ni content and carbon addition on their fracture resistance. Detailed fractographic analyses revealed slightly different mechanisms of fracture associated with the Fe-Ni and carbon content. Fracture toughness values ranging between similar to 12 and similar to 14 MPa m(1/2) were measured. Based upon these findings the SDP route is proposed to improve both the strength and toughness of Ti(C, N) cermets, which can be enhanced by the addition of carbon during the colloidal processing.The authors acknowledge the financial support from the Spanish Government through the projects MAT2015-70780-C4-1-P and MAT2015-70780-C4-2-P, and the Regional Government of Madrid through the program MULTIMAT-CHALLENGE, ref. S2013/MIT-2862. M.Dios acknowledges MINECO through the grant BES-2013-065760

Neutrino scattering on polarized electron target and neutrino magnetic moment

The completed and proposed experiments for the measurement of the neutrino magnetic moment are discussed. To improve the sensitivity of the search for the neutrino magnetic moment we suggest to use a polarized electron target in the processes of neutrino (antineutrino) -- electron scattering. It is shown that in this case the weak interaction term in the total cross section is few times smaller comparing with unpolarized case, but the electromagnetic term does not depend on electron polarization.Comment: 12 pages, 7 figures. Talk given at the XXVIII ITEP Winter School of Physics, Snegiri, Russia, February 22 - March 1, 200