On the fourth root prescription for dynamical staggered fermions

With the aim of resolving theoretical issues associated with the fourth root prescription for dynamical staggered fermions in Lattice QCD simulations, we consider the problem of finding a viable lattice Dirac operator D such that (det D_{staggered})^{1/4} = det D. Working in the flavour field representation we show that in the free field case there is a simple and natural candidate D satisfying this relation, and we show that it has acceptable locality behavior: exponentially local with localisation range vanishing ~ (a/m)^{1/2} for lattice spacing a -> 0. Prospects for the interacting case are also discussed, although we do not solve this case here.Comment: 29 pages, 2 figures; some revision and streamlining of the discussions; results unchanged; to appear in PR

Measurement of Thin Film Thickness by the Crystal Resonance Method

Recent years have seen a tremendous increase in thin film activity. The electronics industry, in particular, has become increasingly active in the development and production of thin film components and complete micro-electronic circuits laid down as thin films. The principal methods of producing thin films are by chemical and electrolytic processes, and by evaporation and sputtering in vacuum. One of the problems associated with film deposition in vacuum involves the measurement of film thickness, a difficult task because: 1) the thicknesses encountered are typically measured in hundreds of angstroms; 2) the films are not physically flat; and 3) they do not display electrical or physical properties consistent with those encountered in bulk material. This thesis describes the application of a recently announced technique for measuring film thickness, and the extension of that technique to verify the growth rate of oxide coatings on metal at room temperature. The method of measurement is based on the change in resonant frequency of a vibrating quartz crystal when any mass is added to (or removed from) its active surface

Strong Ramsey Games in Unbounded Time

For two graphs $B$ and $H$ the strong Ramsey game $\mathcal{R}(B,H)$ on the board $B$ and with target $H$ is played as follows. Two players alternately claim edges of $B$. The first player to build a copy of $H$ wins. If none of the players win, the game is declared a draw. A notorious open question of Beck asks whether the first player has a winning strategy in $\mathcal{R}(K_n,K_k)$ in bounded time as $n\rightarrow\infty$. Surprisingly, in a recent paper Hefetz et al. constructed a $5$-uniform hypergraph $\mathcal{H}$ for which they proved that the first player does not have a winning strategy in $\mathcal{R}(K_n^{(5)},\mathcal{H})$ in bounded time. They naturally ask whether the same result holds for graphs. In this paper we make further progress in decreasing the rank. In our first result, we construct a graph $G$ (in fact $G=K_6\setminus K_4$) and prove that the first player does not have a winning strategy in $\mathcal{R}(K_n \sqcup K_n,G)$ in bounded time. As an application of this result we deduce our second result in which we construct a $4$-uniform hypergraph $G'$ and prove that the first player does not have a winning strategy in $\mathcal{R}(K_n^{(4)},G')$ in bounded time. This improves the result in the paper above. An equivalent formulation of our first result is that the game $\mathcal{R}(K_\omega\sqcup K_\omega,G)$ is a draw. Another reason for interest on the board $K_\omega\sqcup K_\omega$ is a folklore result that the disjoint union of two finite positional games both of which are first player wins is also a first player win. An amusing corollary of our first result is that at least one of the following two natural statements is false: (1) for every graph $H$, $\mathcal{R}(K_\omega,H)$ is a first player win; (2) for every graph $H$ if $\mathcal{R}(K_\omega,H)$ is a first player win, then $\mathcal{R}(K_\omega\sqcup K_\omega,H)$ is also a first player win.Comment: 18 pages, 46 figures; changes: fully reworked presentatio

The effect of mechanical pre-processing and different drying methodologies on bioethanol production using the brown macroalgae Laminaria digitata ((Hudson) JV Lamouroux)

Macroalgae are capable of generating more organic carbon per hectare than terrestrial plants without requiring land, fertiliser or fresh water to grow. In addition, they avoid the food versus fuel argument as they are not a major food source in Europe. In spite of these benefits, macroalgae are not yet fully exploited as a biomass source for bioenergy or platform chemical production in Europe, with one issue being the high harvesting and processing costs. This paper considers the impact of mechanical pre-processing of Laminaria digitata combined with different drying techniques and the effect of these on downstream processing to bioethanol. Results show that mechanically screw pressing macroalgae does enhance conversion to ethanol, but only when the material contains low levels of storage carbohydrates. This occurs in freeze-dried and air-dried samples. The addition of a press aid in the mechanical pre-processing step increases ethanol yields per gramme macroalgae, but due to the presence of the unutilised press aid in the fermentation, ethanol yields were lower overall. The two main findings from this work were (1) simple mechanical processing of L. digitata provides homogenisation and pumpability of macroalgae without negatively affecting subsequent microbial conversion to ethanol. (2) At higher carbohydrate concentrations, screw pressing confers no advantage in ethanol yields over strips of unprocessed kelp, making strips the more viable conversion option for low-input, large-scale processingpublishersversionPeer reviewe

The azimuth structure of nuclear collisions -- I

We describe azimuth structure commonly associated with elliptic and directed flow in the context of 2D angular autocorrelations for the purpose of precise separation of so-called nonflow (mainly minijets) from flow. We extend the Fourier-transform description of azimuth structure to include power spectra and autocorrelations related by the Wiener-Khintchine theorem. We analyze several examples of conventional flow analysis in that context and question the relevance of reaction plane estimation to flow analysis. We introduce the 2D angular autocorrelation with examples from data analysis and describe a simulation exercise which demonstrates precise separation of flow and nonflow using the 2D autocorrelation method. We show that an alternative correlation measure based on Pearson's normalized covariance provides a more intuitive measure of azimuth structure.Comment: 27 pages, 12 figure

Computation of nucleation of a non-equilibrium first-order phase transition using a rare-event algorithm

We introduce a new Forward-Flux Sampling in Time (FFST) algorithm to efficiently measure transition times in rare-event processes in non-equilibrium systems, and apply it to study the first-order (discontinuous) kinetic transition in the Ziff-Gulari-Barshad model of catalytic surface reaction. The average time for the transition to take place, as well as both the spinodal and transition points, are clearly found by this method.Comment: 12 pages, 10 figure

Integrated management strategies for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) remains the fourth leading cause of death, is associated with significant morbidity and places a substantial time and cost burden on the health care system. Unfortunately, treatment for COPD remains underutilized and continues to focus on the acute care of complications. The chronic care model (CCM) shifts this focus from the acute management of symptoms and complications to the prevention and optimal management of the chronic disease. This model utilizes resources from the community and the health care system and emphasizes self-management, provides comprehensive clinic support, and implements evidence-based guidelines and technology into clinical practice to ensure delivery of the highest quality of care. The goal of this review is to use a case-based approach to provide practical information about how integrated care using the CCM can be applied to the clinical care of a complex patient with COPD, shifting the management goals for COPD from reactive to proactive and ultimately improving outcomes

Mechanical Properties of Friction Stir Welds in A12195-T8

An extensive study of the mechanical properties of friction stir welded Al-Li 2195 has been conducted by Lockheed Martin Michoud Space Systems under contract to NASA. The study was part of a development program in which weld parameters were defined for using FSW to assemble large-scale aluminum cryogenic tanks. In excess of 300 feet of 0.320 in. gage plate material was welded and tested. The tests include room temperature and cryogenic temperature tensile tests and surface crack tension (SCT) tests, nondestructive evaluation, metallurgical studies, and photostress analysis. The results of the testing demonstrated improved mechanical properties with FSW as compared to typical fusion welding processes. Increases in ultimate tensile strength, cryogenic enhancement and elongation were observed with the tensile test results. Increased fracture toughness was observed with the SCT results. Nondestructive evaluations were conducted on all welded Joints. No volumetric defects were indicated. Surface indications on the root side of the welds did not significantly affect weld strength. The results of the nondestructive evaluations were confirmed via metallurgical studies. Photostress analysis revealed strain concentrations in multi-pass and heat-repaired FSW's. Details of the tests and results are presented