The impact of bilingualism on the executive control and orienting networks of attention

The main objective of this article is to provide new evidence regarding the impact of bilingualism on the attentional system. We approach this goal by assessing the effects of bilingualism on the executive and orienting networks of attention. In Experiment 1, we compared young bilingual and monolingual adults in a numerical version of the Stroop task, which allowed the assessment of the executive control network. We observed more efficient performance in the former group, which showed both reduced Stroop Interference and larger Stroop Facilitation Effects relative to the latter. Conversely, Experiment 2, conducted with a visual cueing task in order to assess the orienting network, revealed similar Cueing Facilitation and Inhibition (Inhibition of Return - IOR) Effects for both groups of speakers. The implications of the results of these two experiments for the origin and boundaries of the bilingual impact on the attentional system are discussed

Type 0 T-Duality and the Tachyon Coupling

We consider the T-duality relations between Type 0A and 0B theories, and show that this constraints the possible couplings of the tachyon to the RR-fields. Due to the `doubling' of the RR sector in Type 0 theories, we are able to introduce a democratic formulation for the Type 0 effective actions, in which there is no Chern-Simons term in the effective action. Finally we discuss how to embed Type II solutions into Type 0 theories.Comment: some misprints corrected and a reference adde

Family Unification on an Orbifold

We construct a family-unified model on a Z_2xZ_2 orbifold in five dimensions. The model is based on a supersymmetric SU(7) gauge theory. The gauge group is broken by orbifold boundary conditions to a product of grand unified SU(5) and SU(2)xU(1) flavor symmetry. The structure of Yukawa matrices is generated by an interplay between spontaneous breaking of flavor symmetry and geometric factors arising due to field localization in the extra dimension.Comment: 13 page

Closed String Tachyon Condensation on Twisted Circles

We study IIA/B string theory compactified on twisted circles. These models possess closed string tachyons and reduce to type 0B/A theory in a special limit. Using methods of gauged linear sigma models and mirror symmetry we construct a conformal field theory which interpolates between these models and flat space via an auxiliary Liouville direction. Interpreting motion in the Liouville direction as renormalization group flow, we argue that the end point of tachyon condensation in all these models (including 0B/A theory) is supersymmetric type II theory. We also find a zero-slope limit of these models which is best described in a T-dual picture as a type II NS-NS fluxbrane. In this limit tachyon condensation is an interesting and well posed problem in supergravity. We explicitly determine the tachyon as a fluctuation of supergravity fields, and perform a rudimentary numerical analysis of the relevant flows.Comment: 21 pages plus appendices (12 pages), harvmac, 1 fig, v2: minor changes and references added, v3: minor changes version published in JHE

VIM-1, VIM-34, and IMP-8 Carbapenemase-Producing Escherichia coli strains recovered from a Portuguese river

[No abstract available]This work was supported by the University of Fribourg

Closed String Tachyons and Semi-Classical Instabilities

We conjecture that the end point of bulk closed string tachyon decay at any non-zero coupling, is the annihilation of space time by Witten's bubble of nothing, resulting in a topological phase of the theory. In support of this we present a variety of situations in which there is a correspondence between the existence of perturbative tachyons in one regime and the semi-classical annihilation of space-time. Our discussion will include many recently investigated scenarios in string theory including Scherk-Schwarz compactifications, Melvin magnetic backgrounds, and noncompact orbifolds. We use this conjecture to investigate a possible web of dualities relating the eleven-dimensional Fabinger-Horava background with nonsupersymmetric string theories. Along the way we point out where our conjecture resolves some of the puzzles associated with bulk closed string tachyon condensation.Comment: 31 pages, 5 figures 3 figures added, typos corrected and references added. Discussion of Type 0/Heterotic s-duality extended and some other points clarified Revision of discussion on Fabinger-Horava string descendents, section on Scherk-Schwarz compactification of Horava-Witten removed, some references adde