Memory texts and memory work: Performances of memory in and with visual media

The online version of this article can be found at: http://mss.sagepub.com/content/early/2010/05/24/175069801037003

Ordovician conodonts from the Mithaka Formation (Georgina Basin, Australia). Regional and paleobiogeographical implications

The systematic analysis of conodonts from the previously unstudied Mithaka Formation (Georgina Basin) yielded 1366 identifiable elements, representing 25 species and 21 genera. One new species was recovered and identified, Triangulodus mithakensis n. sp. Four other new species are described in open nomenclature as Bergstroemognathus? n. sp. A, ?Periodon n. sp. A, Phragmodus n. sp. A and Taoqupognathus n. sp. A. The Mithaka Fm fauna shows similarity with conodonts from several previous Australian studies and lesser similarity with conodonts from North China and North America. Some species of North American Midcontinent (Laurentian Province) affinity include Erismodus quadridactylus (STAUFFER) and Staufferella divisa SWEET, whereas some species of North Chinese affinity include Aurilobodus leptosomatus AN, Panderodus nogamii (LEE) and ?Serratognathus sp. However, many species are distinctly Australian: Bergstroemognathus? n. sp. A, ?Periodon n. sp. A, Phragmodus n. sp. A, Drucognathus yiranus ZHANG, BARNES and COOPER, Erismodus nicolli ZHANG, BARNES and COOPER, Yaoxianognathus? neonychodonta ZHANG, BARNES and COOPER, Triangulodus mithakensis n. sp. and Taoqupognathus n. sp. A. These Australian species support the placement of the Mithaka Fm fauna within the proposed Australian Province. This new conodont fauna is correlated to the early Late Ordovician upper Drucognathus yiranus Zone of the Amadeus Basin, Central Australia and the late Gisbornian Stage. The conodont fauna indicates a shallow open lagoon depositional environment

Forces and pressures induced on circular plates by a single lifting jet in ground effect

NASA Ames is conducting a program to develop improved methods for predicting suckdown and hot-gas ingestion on jet V/STOL aircraft when they are in ground effect. As part of that program a data base is being created that provides a systematic variation of parameters so that current empirical prediction procedures can be modified. The first series of tests in this program is complete. This report is one of three that presents the data obtained from tests conducted at Lockheed Aeronautical Systems - Rye Canyon Facility and the High Bay area of the 40 by 80 foot Wind Tunnel at Ames Research Center. Suckdown on two circular plates is examined

Suckdown, fountain lift, and pressures induced on several tandem jet V/STOL configurations

As part of a program to improve the methods for predicting the suckdown and hot gas ingestion for jet V/STOL aircraft in ground effect, a data base is being created that provides a systematic variation of parameters so that a new empirical prediction procedure can be developed. The first series of tests in this program was completed. Suckdown, fountain lift, and pressures induced on several two-jet V/STOL configurations are described. It is one of three reports that present the data obtained from tests conducted at Lockheed Aeronautical Systems-Rye Canyon Facility and in the High Bay area of the 40 by 80 foot wind tunnel complex at NASA Ames Research Center

Microscopic theory of quantum-transport phenomena in mesoscopic systems: A Monte Carlo approach

A theoretical investigation of quantum-transport phenomena in mesoscopic systems is presented. In particular, a generalization to ``open systems'' of the well-known semiconductor Bloch equations is proposed. The presence of spatial boundary conditions manifest itself through self-energy corrections and additional source terms in the kinetic equations, whose form is suitable for a solution via a generalized Monte Carlo simulation. The proposed approach is applied to the study of quantum-transport phenomena in double-barrier structures as well as in superlattices, showing a strong interplay between phase coherence and relaxation.Comment: to appear in Phys. Rev. Let

Localization of Matter Waves in 2D-Disordered Optical Potentials

We consider ultracold atoms in 2D-disordered optical potentials and calculate microscopic quantities characterizing matter wave quantum transport in the non-interacting regime. We derive the diffusion constant as function of all relevant microscopic parameters and show that coherent multiple scattering induces significant weak localization effects. In particular, we find that even the strong localization regime is accessible with current experimental techniques and calculate the corresponding localization length.Comment: 4 pages, 3 figures, figures changed, references update

Opinion dynamics with emergent collective memory: A society shaped by its own past

In order to understand the development of common orientation of opinions in the modern world we propose a model of a society described as a large collection of agents that exchange their expressed opinions under the influence of their mutual interactions and external events. In particular we introduce an interaction bias which results in the emergence of a collective memory such that the society is able to store and recall information coming from several external signals. Our model shows how the inner structure of the society and its future reactions are shaped by its own history. We provide an analytical explanation of such mechanism and we study the features of external influences with higher impact on the society. We show the emergent similarity between the reaction of a society modelled in this way and the Hopfield-like mechanism of information retrieval in Neural Networks

Structural Transition Kinetics and Activated Behavior in the Superconducting Vortex Lattice

Using small-angle neutron scattering, we investigated the behavior of a metastable vortex lattice state in MgB2 as it is driven towards equilibrium by an AC magnetic field. This shows an activated behavior, where the AC field amplitude and cycle count are equivalent to, respectively, an effective "temperature" and "time". The activation barrier increases as the metastable state is suppressed, corresponding to an aging of the vortex lattice. Furthermore, we find a cross-over from a partial to a complete suppression of metastable domains depending on the AC field amplitude, which may empirically be described by a single free parameter. This represents a novel kind of collective vortex behavior, most likely governed by the nucleation and growth of equilibrium vortex lattice domains.Comment: 5 pages plus 3 pages of supplemental materia