A multi-layer extension of the stochastic heat equation

Motivated by recent developments on solvable directed polymer models, we define a 'multi-layer' extension of the stochastic heat equation involving non-intersecting Brownian motions.Comment: v4: substantially extended and revised versio

Statistically determined dispersion relations of magnetic field fluctuations in the terrestrial foreshock

We obtain dispersion relations of magnetic field fluctuations for two crossings of the terrestrial foreshock by Cluster spacecraft. These crossings cover plasma conditions that differ significantly in their plasma β and in the density of the reflected ion beam, but not in the properties of the encountered ion population, both showing shell-like distribution function. Dispersion relations are reconstructed using two-point instantaneous wave number estimations from pairs of Cluster spacecraft. The accessible range of wave vectors, limited by the available spacecraft separations, extends to ≈2 × 104 km. Results show multiple branches of dispersion relations, associated with different powers of magnetic field fluctuations. We find that sunward propagating fast magnetosonic waves and beam resonant modes are dominant for the high plasma β interval with a dense beam, while the dispersions of the interval with low beam density include Alfvén and fast magnetosonic modes propagating sunward and anti-sunward

Drivers of intrapopulation variation in resource use in a generalist predator, the macaroni penguin

Intrapopulation variation in resource use occurs in many populations of generalist predators with important community and evolutionary implications. One of the hypothesised mechanisms for such widespread variation is ecological opportunity, i.e. resource availability determined by intrinsic constraints and extrinsic conditions. We combined tracking data and stable isotope analysis to examine how breeding constraints and prey conditions influenced intrapopulation variation in resource use among macaroni penguins Eudyptes chrysolophus. Isotopic variation was also examined as a function of breeding success, individual traits and individual specialisation. Variation in isotope ratios was greatest across multiple tissue types when birds were able to undertake mid-range foraging trips (i.e. during incubation and pre-moult). This variation was highly consistent between years that spanned a 3-fold difference in local krill Euphausia superba density and was also highly consistent at the individual level between 2 years that had similar krill densities. However, by comparing our results with previous work on the same population, it appeared that a decrease in local prey availability can increase intrapopulation variation in resource use during periods with more restricted foraging ranges (i.e. during brood-guard and crèche). This study highlights the importance of considering ecological interactions that operate on multiple spatio-temporal scales when examining the drivers of resource use in populations of generalist predators

Carbon nanotube four-terminal devices for pressure sensing applications

Carbon nanotubes (CNTs) are of high interest for sensing applications,owing to their superior mechanical strength, high Young’s modulus and low density. In this work, we report on a facile approach for the fabrication of carbon nanotube devices using a four terminal configuration. Oriented carbon nanotube films were pulled out from a CNT forest wafer and then twisted into a yarn. Both the CNT film and yarn were arranged on elastomer membranes/diaphragms which were arranged on a laser cut acrylic frame to form pressure sensors. The sensors were calibrated using a precisely controlled pressure system, showing a large change of the output voltage of approximately 50 mV at a constant supply current of 100 μA and under a low applied pressure of 15 mbar. The results indicate the high potential of using CNT films and yarns for pressure sensing applications

Isospin Breaking and ω\omega->ππ\pi\pi Decay

We study $\omega\to\pi^+\pi^-$ decay up to including all orders of the chiral expansion and one-loop level of mesons in formlism of chiral constituent quark model. This G-parity forbidden decay is caused by $m_u\neq m_d$ and electromagnetic interaction of mesons. We illustrate that in the formlism both nonresonant contact interaction and $\rho$ resonance exchange contribute to this process, and the contribution from $\rho$ resonance exchange is dominant. We obtain that transition matrix element is $=[-(3956\pm 280)-(1697\pm 130)i]$MeV$^2$, and isospin breaking parameter is $m_d-m_u=3.9\pm 0.22$MeV at energy scale $\mu\sim m_\omega$.Comment: Revtex file, 16 pages, four eps figur

Dynamics of a tagged particle in the asymmetric exclusion process with the step initial condition

The one-dimensional totally asymmetric simple exclusion process (TASEP) is considered. We study the time evolution property of a tagged particle in TASEP with the step-type initial condition. Calculated is the multi-time joint distribution function of its position. Using the relation of the dynamics of TASEP to the Schur process, we show that the function is represented as the Fredholm determinant. We also study the scaling limit. The universality of the largest eigenvalue in the random matrix theory is realized in the limit. When the hopping rates of all particles are the same, it is found that the joint distribution function converges to that of the Airy process after the time at which the particle begins to move. On the other hand, when there are several particles with small hopping rate in front of a tagged particle, the limiting process changes at a certain time from the Airy process to the process of the largest eigenvalue in the Hermitian multi-matrix model with external sources.Comment: 48 pages, 8 figure

The relationship between healthy lifestyle behaviours and outcomes for people living with and beyond cancer: an overview of Systematic Reviews

There are an extensive number of published evidence reviews examining the influence of lifestyle behaviours on cancer outcomes. Healthy lifestyles are a significant topic of debate in oncology and in policy and practice organisations that support people living with and beyond cancer. Such reviews vary in quality, address different relationships, outcomes and cancers, and there is often more than one review on important topics. This makes it difficult for policy and practice professionals to make decisions about the prescription and promotion of lifestyle behaviours for cancer populations. An overview of systematic reviews provides a single, overarching summary of evidence from published systematic reviews and compares and contrasts the findings of systematic reviews, providing healthcare professionals with the evidence needed for more effective decision making (Smith et al. 2011). This overview of systematic reviews synthesises evidence from systematic reviews on smoking, physical activity, dietary behaviours and alcohol consumption to present a summary of evidence about the relationships between these lifestyle behaviours and outcomes for people living with and beyond cancer

Extracting Br(omega->pi^+ pi^-) from the Time-like Pion Form-factor

We extract the G-parity-violating branching ratio Br(omega->pi^+ pi^-) from the effective rho-omega mixing matrix element Pi_{rho omega}(s), determined from e^+e^- -> pi^+ pi^- data. The omega->pi^+ pi^- partial width can be determined either from the time-like pion form factor or through the constraint that the mixed physical propagator D_{rho omega}^{mu nu}(s) possesses no poles. The two procedures are inequivalent in practice, and we show why the first is preferred, to find finally Br(omega->pi^+ pi^-) = 1.9 +/- 0.3%.Comment: 12 pages (published version