The origin of the E+ transition in GaAsN alloys

Optical properties of GaAsN system with nitrogen concentrations in the range of 0.9-3.7% are studied by full-potential LAPW method in a supercell approach. The E+ transition is identified by calculating the imaginary part of the dielectric function. The evolution of the energy of this transition with nitrogen concentration is studied and the origin of this transition is identified by analyzing the contributions to the dielectric function from different band combinations. The L_1c-derived states are shown to play an important role in the formation of the E+ transition, which was also suggested by recent experiments. At the same time the nitrogen-induced modification of the first conduction band of the host compound are also found to contribute significantly to the E+ transition. Further, the study of several model supercells demonstrated the significant influence of the nitrogen potential on the optical properties of the GaAsN system.Comment: 5 pages, 3 figure

Arqueologías de la mobilidad: cruzando los límites espaciales y temporales

En este artículo se delinea la historia de los enfoques arqueológicos sobre el movimiento y la movilidad y se discute la reciente aparición de un “nuevo paradigma de movilidades” en muchas disciplinas, incluyendo la arqueología, en el que los temas más frecuentemente explorados se centran en torno a redes, flujos, tierra natal, globalización, migración, colonialismo y colonización, arqueología multi-local, transiciones y transformaciones, y affordances de lugar y espacio. Los autores respaldan un enfoque basado en la trayectoria del movimiento que se centra en las relaciones fluidas entre personas, objetos, tiempo y espacio y proporcionan una visión general de la literatura reciente sobre estudios de casos en arqueologías de lamovilidad.This article traces the history of archaeological approaches to movement and mobility and discusses the recent emergence of a “new mobilities paradigm” across many disciplines, including archaeology, in which the themes most often explored center around networks, flows, homelands, globalization, migration, colonialism and colonization, multi-sited archaeology, transitions and transformations, and affordances of place and space. The authors endorse a trajectory-based approach to movement that focuses on fluid relationships among people, objects, time, and space and provide an overview of recent literature about and case studies in archaeologies of mobility.Published versio

Rescue and Recovery in the Space Age (Search, Rescue and Recovery)

This paper will be presented by Colonel Emil G. Beaudry, Vice Commander, Aerospace Rescue and Recovery Service. It will include a statement of the present Aerospace Rescue and Recovery Service mission and how it relates specifically to our country\u27s various space programs, past, present, and as far into the future as we can project. It will cover the introduction of the HC-130\u27s into the Aerospace Rescue and Recovery Service inventory, the Fulton System and its potential, the possibilities of air-to-air recovery and the entirely new concepts of air-to-air refueling of the HH-3 helicopter from the HC-130H aircraft and rnid-air recovery of aerospace hardware and personnel. It will conclude with an investigation of our need for rescue in space as a logical extension of the historic ARRS humanitarian approach to people in distress within the sensible atmosphere. Each of the general areas will be investigated in depth

Flipping quantum coins

Coin flipping is a cryptographic primitive in which two distrustful parties wish to generate a random bit in order to choose between two alternatives. This task is impossible to realize when it relies solely on the asynchronous exchange of classical bits: one dishonest player has complete control over the final outcome. It is only when coin flipping is supplemented with quantum communication that this problem can be alleviated, although partial bias remains. Unfortunately, practical systems are subject to loss of quantum data, which restores complete or nearly complete bias in previous protocols. We report herein on the first implementation of a quantum coin-flipping protocol that is impervious to loss. Moreover, in the presence of unavoidable experimental noise, we propose to use this protocol sequentially to implement many coin flips, which guarantees that a cheater unwillingly reveals asymptotically, through an increased error rate, how many outcomes have been fixed. Hence, we demonstrate for the first time the possibility of flipping coins in a realistic setting. Flipping quantum coins thereby joins quantum key distribution as one of the few currently practical applications of quantum communication. We anticipate our findings to be useful for various cryptographic protocols and other applications, such as an online casino, in which a possibly unlimited number of coin flips has to be performed and where each player is free to decide at any time whether to continue playing or not.Comment: 17 pages, 3 figure

Loss of the Desmosomal Component Perp Impairs Wound Healing In Vivo

Epithelial wound closure is a complex biological process that relies on the concerted action of activated keratinocytes and dermal fibroblasts to resurface and close the exposed wound. Modulation of cell-cell adhesion junctions is thought to facilitate cellular proliferation and migration of keratinocytes across the wound. In particular, desmosomes, adhesion complexes critical for maintaining epithelial integrity, are downregulated at the wound edge. It is unclear, however, how compromised desmosomal adhesion would affect wound reepithelialization, given the need for a delicate balance between downmodulating adhesive strength to permit changes in cellular morphology and maintaining adhesion to allow coordinated migration of keratinocyte sheets. Here, we explore the contribution of desmosomal adhesion to wound healing using mice deficient for the desmosomal component Perp. We find that Perp conditional knockout mice display delayed wound healing relative to controls. Furthermore, we determine that while loss of Perp compromises cell-cell adhesion, it does not impair keratinocyte proliferation and actually enhances keratinocyte migration in in vitro assays. Thus, Perp's role in promoting cell adhesion is essential for wound closure. Together, these studies suggest a role for desmosomal adhesion in efficient wound healing

Processing Succinct Matrices and Vectors

We study the complexity of algorithmic problems for matrices that are represented by multi-terminal decision diagrams (MTDD). These are a variant of ordered decision diagrams, where the terminal nodes are labeled with arbitrary elements of a semiring (instead of 0 and 1). A simple example shows that the product of two MTDD-represented matrices cannot be represented by an MTDD of polynomial size. To overcome this deficiency, we extended MTDDs to MTDD_+ by allowing componentwise symbolic addition of variables (of the same dimension) in rules. It is shown that accessing an entry, equality checking, matrix multiplication, and other basic matrix operations can be solved in polynomial time for MTDD_+-represented matrices. On the other hand, testing whether the determinant of a MTDD-represented matrix vanishes PSPACE$-complete, and the same problem is NP-complete for MTDD_+-represented diagonal matrices. Computing a specific entry in a product of MTDD-represented matrices is #P-complete.Comment: An extended abstract of this paper will appear in the Proceedings of CSR 201

Media Reporting and Business Cycles: Empirical Evidence based on News Data

Recent literature suggests that news shocks could be an important driver of economic cycles. In this article, we use a direct measure of news sentiment derived from media reports. This allows us to examine whether innovations in the reporting tone correlate with changes in the assessment and expectations of the business situation as reported by firms in the German manufacturing sector. We fi nd that innovations in news reporting affect business expectations, even when conditioning on the current business situation and industrial production. The dynamics of the empirical model con rm theoretical predictions that news innovations affect real variables such as production via changes in expectations. Looking at individual sectors within manufacturing, we fi nd that macroeconomic news is at least as important for business expectations as sector-spefici c news. This is consistent with the existence of information complementarities across sectors