The structural properties of the multi-layer graphene/4H-SiC(000-1) system as determined by Surface X-ray Diffraction

We present a structural analysis of the multi-layer graphene-4HSiC(000-1}) system using Surface X-Ray Reflectivity. We show for the first time that graphene films grown on the C-terminated (000-1}) surface have a graphene-substrate bond length that is very short (0.162nm). The measured distance rules out a weak Van der Waals interaction to the substrate and instead indicates a strong bond between the first graphene layer and the bulk as predicted by ab-initio calculations. The measurements also indicate that multi-layer graphene grows in a near turbostratic mode on this surface. This result may explain the lack of a broken graphene symmetry inferred from conduction measurements on this system [C. Berger et al., Science 312, 1191 (2006)].Comment: 9 pages with 6 figure

Image-potential states on clean and hydrogen-covered Pd surfaces: Analysis of a one-dimensional model

Theoretical calculations in a one-dimensional model give the energies of surface states on clean and hydrogen-covered Pd surfaces in very good agreement with those measured by high-resolution electron energy-loss spectroscopy and inverse photoemission experiments. Some general properties and the applicability of this class of one-dimensional models are discussed

Measuring Active-to-Sterile Neutrino Oscillations with Neutral Current Coherent Neutrino-Nucleus Scattering

Light sterile neutrinos have been introduced as an explanation for a number of oscillation signals at $\Delta m^2 \sim 1$ eV$^2$. Neutrino oscillations at relatively short baselines provide a probe of these possible new states. This paper describes an accelerator-based experiment using neutral current coherent neutrino-nucleus scattering to strictly search for active-to-sterile neutrino oscillations. This experiment could, thus, definitively establish the existence of sterile neutrinos and provide constraints on their mixing parameters. A cyclotron-based proton beam can be directed to multiple targets, producing a low energy pion and muon decay-at-rest neutrino source with variable distance to a single detector. Two types of detectors are considered: a germanium-based detector inspired by the CDMS design and a liquid argon detector inspired by the proposed CLEAR experiment.Comment: 10 pages, 7 figure

A Shared Dataspace Language Supporting Larger-Scale Concurrency

Our ultimate goal is to develop the software support needed for the design, analysis, understanding, and testing of programs involving many thousands of concurrent processes running on a highly parallel multiprocessor. We are currently evaluating the use of a shared dataspace paradigm as the basis for a new programming language supporting large-scale concurrency. The language is called SDL (Shared Dataspace Language). In SDL, a content-addressable dataspace is examined and altered by concurrent processes using atomic transactions much like those in a traditional database. Associated with each process is a programmer-defined view. The view is a mechanism which allows processes to interrogate the dataspace at a level of abstraction convenient for the task they are pursuing. This paper provides an overview of the key SDL features. Small examples are used to illustrate the power and flexibility of the language. They also serve as a backdrop against which we discuss programming style implications of the shared dataspace paradigm

CTIX Message System User\u27s Manual Version 1.0

This manual describes how to use the CTIX Message System for interprocess communication in a distributed application program. The CTIX Message System is a package of message-passing facilities developed by the Concurrent Systems Group of the Department of Computer Science at Washington University, It provides a process-to-process asynchronous, buffered communication medium. The package is implemented on a network of Convergent Technologies (CT) MiniFrame workstations. These workstations support the CTIX (the Ct\u27s version of UNIX System V) operating system and the TCP/IP network protocols

FGFR2 amplification in colorectal adenocarcinoma

FGFR2 is recurrently amplified in 5% of gastric cancers and 1%–4% of breast cancers; however, this molecular alteration has never been reported in a primary colorectal cancer specimen. Preclinical studies indicate that several FGFR tyrosine-kinase inhibitors (TKIs), such as AZD4547, have in vitro activity against the FGFR2-amplified colorectal cell line, NCI-H716. The efficacy of these inhibitors is currently under investigation in clinical trials for breast and gastric cancer. Thus, better characterizing colorectal tumors for FGFR2 amplification could identify a subset of patients who may benefit from FGFR TKI therapies. Here, we describe a novel FGFR2 amplification identified by clinical next-generation sequencing in a primary colorectal cancer. Further characterization of the tumor by immunohistochemistry showed neuroendocrine differentiation, similar to the reported properties of the NCI-H716 cell line. These findings demonstrate that the spectrum of potentially clinically actionable mutations detected by targeted clinical sequencing panels is not limited to only single-nucleotide polymorphisms and insertions/deletions but also to copy-number alterations.</jats:p

Effect of Rotor- and Stator-Blade Modifications on Surge Performance of an 11-Stage Axial-Flow Compressor. I - Original Production Compressor of XJ40-WE-6 Engine

An investigation to increase the compressor surge-limit pressure ratio of the XJ40-WE-6 turbojet engine at high equivalent speeds was conducted at the NACA Lewis altitude wind tunnel. This report evaluates the compressor modifications which were restricted to (1) twisting rotor blades (in place) to change blade section angles and (2) inserting new stator diaphragms with different blade angles. Such configuration changes could be incorporated quickly and easily in existing engines at overhaul depots. It was found that slight improvements in the compressor surge limit were possible by compressor blade adjustment. However, some of the modifications also reduced the engine air flow and hence penalized the thrust. The use of a mixer assembly at the compressor outlet improved the surge limit with no appreciable thrust penalty