Repeat-Accumulate Codes for Reconciliation in Continuous Variable Quantum Key Distribution

This paper investigates the design of low-complexity error correction codes for the verification step in continuous variable quantum key distribution (CVQKD) systems. We design new coding schemes based on quasi-cyclic repeat-accumulate codes which demonstrate good performances for CVQKD reconciliation

All tree-level amplitudes in massless QCD

We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to three massless quark-anti-quark pairs. A general formula is presented based on the combinatorics of paths along a rooted tree and associated determinants. Explicit expressions are displayed for the next-to-maximally helicity violating (NMHV) and next-to-next-to-maximally helicity violating (NNMHV) gauge theory amplitudes. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric Yang-Mills theory (N=4 SYM) onto the relevant components yielding all gluon-gluino tree amplitudes in N=4 SYM. We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different flavors as well as a single electroweak vector boson. The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all N=4 SYM gluon-gluino trees. These in turn yield all QCD trees with up to four external arbitrary-flavored massless quark-anti-quark-pairs.Comment: 40 pages, Mathematica package GGT.m and example notebook is included in submission, v2: QCD four fermion line translations provided; GGT version 1.1 update with a numerical evaluation function; comments on computer speed optimizations, v3: Minor changes, version to be published in JHEP, v4: published version in JHE

Design and manufacturing concepts for thermoplastic structures

Results to date on the application of two manufacturing techniques, fiber placement and single diaphragm/coconsolidation, to produce cost-effective, thermoplastic composite (TPC), primary fuselage structure are presented. Applications relative to fuselage upper cover structure indicate potential cost savings relative to conventional approaches. Progress is also presented on efforts concerned with other design details which take advantage of thermoplastic composites such as fastener less stiffener/frame attachments. In addition, results are presented on the development and verification testing of a composite lug analysis program which incorporates through-the-thickness effects

Bootstrapping six-gluon scattering in planar N=4{\cal N}=4 super-Yang-Mills theory

We describe the hexagon function bootstrap for solving for six-gluon scattering amplitudes in the large $N_c$ limit of ${\cal N}=4$ super-Yang-Mills theory. In this method, an ansatz for the finite part of these amplitudes is constrained at the level of amplitudes, not integrands, using boundary information. In the near-collinear limit, the dual picture of the amplitudes as Wilson loops leads to an operator product expansion which has been solved using integrability by Basso, Sever and Vieira. Factorization of the amplitudes in the multi-Regge limit provides additional boundary data. This bootstrap has been applied successfully through four loops for the maximally helicity violating (MHV) configuration of gluon helicities, and through three loops for the non-MHV case.Comment: 15 pages, 3 figures, 2 tables; contribution to the proceedings of Loops and Legs in Quantum Field Theory, 27 April - 2 May 2014, Weimar, Germany; v2, reference adde

Affect, Interpersonal Behaviour and Interpersonal Perception During Open-Label, Uncontrolled Paroxetine Treatment of People with Social Anxiety Disorder: A Pilot Study

Background: Laboratory-based research with community samples has suggested changes in affective, behavioural and cognitive processes as possible explanations for the effects of serotonergic medications. Examining the effects of serotonergic medications using an ecological momentary measure (such as event-contingent recording) in the daily lives of people with social anxiety disorder would contribute to establishing the effects of these medications on affect, behaviour and one form of cognition: perception of others’ behaviour. Methods: The present study assessed changes in affect, interpersonal behaviour and perception of others’ behaviour in adults with social anxiety disorder using ecological momentary assessment at baseline and over 4 months of a single-arm, uncontrolled, open-label trial of treatment with the selective serotonin reuptake inhibitor paroxetine. Results: Anxiety and concurrent depressive symptoms decreased. Participants also reported increased positive and decreased negative affect; increased agreeable and decreased quarrelsome behaviour; increased dominant and decreased submissive behaviour; and increased perception that others behaved agreeably toward them. Moreover, participants demonstrated reduced intraindividual variability in affect, interpersonal behaviour and perception of others’ behaviour. Limitations: Limitations included the lack of a placebo group, the inability to identify the temporal order of changes and the restricted assessment of extreme behaviour. Conclusion: The results of the present study demonstrate changes during pharmacotherapy in the manifestation of affect, interpersonal behaviour and interpersonal perception in the daily lives of people with social anxiety disorder. Given the importance of interpersonal processes to social anxiety disorder, these results may guide future research seeking to clarify mechanisms of action for serotonergic medications

Compaction and Chemical Grouting for Drain Tunnels in Phoenix

Ground runs during ml.m.ng of the Papago Freeway Drain Tunnels posed significant potential risk to utilities, street pavement, and buildings located above and adjacent to one of the three tunnel alignments. Ground response to the larger ground runs resulted in open chimneys and settlement of the ground surface of up to several feet. Modifications to the tunneling machine included addition of poling plates and breasting boards. Further modification to the tunneling method included use of compaction grouting in conjunction with mining for the entire length of one tunnel alignment, and use of chemical grouting to prestabilize the ground surrounding the tunnel opening in areas of high risk utilities and in areas where subsurface conditions suggested that running ground would be encountered during mining. This paper presents a summary of the ground behavior with and without the compaction and chemical grouting and describes the grouting methods

Effect of specimen geometry and aps flash bond coating on TBC lifetime

Thermal barrier coatings (TBCs) for land-based gas turbines are primarily thermally sprayed and are unlikely to contain precious metals. For regions of the world where natural gas prices are high, turbine efficiency is a critical issue, however, durability and reliability also are very important for large scale generation. Seeking pathways for improved performance and lifetime model development, a variety of TBC performance parameters have been investigated over the years using furnace cycle testing, including bond coating composition, substrate composition, cycle frequency and environment (i.e. additions of H2O, CO2, etc.). The baseline system has been superalloy 247 substrates with high velocity oxygen fuel (HVOF) NiCoCrAlYHfSi bond coatings and air plasma sprayed yttria-stabilized zirconia (YSZ) top coatings tested in “wet” air (10%H2O) at 900°-1150°C. Recently, specimen geometry was changed from flat disks to rods. Using similar coating parameters, FCT lifetime in 100-h cycles at 1100°C in air with 10%H2O dropped by ~5X for rods compared to disks. Coating architectures that were developed for flat disk specimens did not appear to be effective in improving lifetime in FCT for rod specimens. The addition of an APS “flash” coating resulted in a significant increase in FCT lifetime in rod specimens. The benefit of this additional bond coating layer has generally thought to be due to increased interface roughness compared to a conventional HVOF coating. The most recent testing has returned to 1-h FCT of disk specimens using ~50µm APS flash coatings of both NiCoCrAlYHfSi and NiCoCrAlY flash coatings deposited on HVOF NiCoCrAlYHfSi. A similar set of rod specimens also is being evaluated in 100-h cycles. Both tests are being conducted at 1100°C in air with 10%H2O. Both flash coatings show a statistically significant increase in FCT TBC lifetime in 1-h cycles. Surprisingly, the Y only flash coating has significantly outperformed the YHfSi flash coating with some work still in progress. Residual stress in the thermally grown alumina scale has been tracked every 100 1-h cycles and 5, 100-h cycles for one sample of each coating type to quantify the evolution of the reaction product and better understand the FCT results. Failed specimens are being characterized to better understand the benefit of flash coatings on TBC lifetime. Research was sponsored by the U. S. Department of Energy, Office of Fossil Energy, Turbine Program