Accelerating Neoproterozoic research through scientific drilling

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Counting BPS operators in N=4 SYM

The free field partition function for a generic U(N) gauge theory, where the fundamental fields transform in the adjoint representation, is analysed in terms of symmetric polynomial techniques. It is shown by these means how this is related to the cycle polynomial for the symmetric group and how the large N result may be easily recovered. Higher order corrections for finite N are also discussed in terms of symmetric group characters. For finite N, the partition function involving a single bosonic fundamental field is recovered and explicit counting of multi-trace quarter BPS operators in free \N=4 super Yang Mills discussed, including a general result for large N. The partition function for BPS operators in the chiral ring of \N=4 super Yang Mills is analysed in terms of plane partitions. Asymptotic counting of BPS primary operators with differing R-symmetry charges is discussed in both free \N=4 super Yang Mills and in the chiral ring. Also, general and explicit expressions are derived for SU(2) gauge theory partition functions, when the fundamental fields transform in the adjoint, for free field theory.Comment: 38 pages, uses harvmac, v.2. references added, typos corrected, discussion of asymptotic counting included for more general chiral ring, v.3. typos corrected, discussion for su(2) simplified, to be published in Nuclear Physics

How to increase and maintain high immunization coverage: Vaccination Demand Resilience (VDR) framework

Background: Resilience in vaccination demand is ever more critical as the COVID-19 pandemic has increased our understanding of the importance of vaccines on health and well-being. Yet timid demand for COVID-19 vaccines where available and reduced uptake of routine immunizations globally further raise the urgent need to build vaccination resilience. We demonstrate the complexity of vaccination demand and resilience in a framework where relevant dimensions are intertwined, fluid, and contextual. Methods: We developed the Vaccination Demand Resilience (VDR) framework based on a literature review on vaccination demand and expert consultation. The matrix framework builds on three main axes: 1) vaccination attitudes and beliefs; 2) vaccination seeking behavior; and 3) vaccination status. The matrix generated eight quadrants, which can help explain people's levels of vaccination demand and resilience. We selected four scenarios as examples to demonstrate different interventions that could move people across quadrants and build vaccination resilience. Results: Incongruence between individuals’ attitudes and beliefs, vaccination behavior, and vaccination status can arise. For example, an individual can be vaccinated due to mandates but reject vaccination benefits and otherwise avoid seeking vaccination. Such incongruence could be altered by interventions to build resilience in vaccination demand. These interventions include information, education and communication to change individuals' vaccination attitudes and beliefs, incentive programs and reminder-recalls to facilitate vaccination seeking, or by strengthening healthcare provider communications to reduce missed opportunities. Conclusions: Vaccination decision-making is complex. Individuals can be vaccinated without necessarily accepting the benefits of vaccination or seeking vaccination, threatening resilience in vaccination demand. The VDR framework can provide a useful lens for program managers and policy makers considering interventions and policies to improve vaccination resilience. This would help build and sustain confidence and demand for vaccinations, and help to continue to prevent disease, disability, and death from vaccine-preventable diseases

W_{1+\infty} and W(gl_N) with central charge N

We study representations of the central extension of the Lie algebra of differential operators on the circle, the W-infinity algebra. We obtain complete and specialized character formulas for a large class of representations, which we call primitive; these include all quasi-finite irreducible unitary representations. We show that any primitive representation with central charge N has a canonical structure of an irreducible representation of the W-algebra W(gl_N) with the same central charge and that all irreducible representations of W(gl_N) with central charge N arise in this way. We also establish a duality between "integral" modules of W(gl_N) and finite-dimensional irreducible modules of gl_N, and conjecture their fusion rules.Comment: 29 pages, Latex, uses file amssym.def (a few remarks added, typos corrected

Electromagnetic characteristics of bilayer quantum Hall systems in the presence of interlayer coherence and tunneling

The electromagnetic characteristics of bilayer quantum Hall systems in the presence of interlayer coherence and tunneling are studied by means of a pseudospin-texture effective theory and an algebraic framework of the single-mode approximation, with emphasis on clarifying the nature of the low-lying neutral collective mode responsible for interlayer tunneling phenomena. A long-wavelength effective theory, consisting of the collective mode as well as the cyclotron modes, is constructed. It is seen explicitly from the electromagnetic response that gauge invariance is kept exact, this implying, in particular, the absence of the Meissner effect in bilayer systems. Special emphasis is placed on exploring the advantage of looking into quantum Hall systems through their response; in particular, subtleties inherent to the standard Chern-Simons theories are critically examined.Comment: 9 pages, Revtex, to appear in Phys. Rev.

Failures in transport infrastructure embankments

To ensure that road and rail transport networks remain operational, both highway and railway embankments require continual maintenance and renewal to mitigate against ongoing deterioration and repair any sections damaged by realised failures. This paper provides a review of recent developments in the understanding of highway and railway embankment degradation and failure. Failures due to pore water pressure increase, seasonal shrink-swell deformation and progressive failure are considered. The material composition and construction of highway and railway embankments differ, which influences the dominant type and timing of embankment failure. There is evidence for highway embankment failures induced by pore water pressure increase, but not seasonal deformation and progressive failure. Some railway embankments are susceptible to pore water pressure increase, seasonal shrink-swell deformation and progressive failure due to the age and nature of the dumped clay fill used in their construction. The approaches used to measure and explore embankment failure mechanisms are compared and discussed. Field observations have been used to understand pore water pressure increase and seasonal shrink-swell deformation in embankments, while the investigation of progressive embankment failure has mainly utilised physical and numerical modelling approaches. Further field and laboratory investigation is required before the rigorous analysis of embankment failure can be routinely undertaken. However, progress is being made to empirically identify and evaluate the various risk factors affecting transport infrastructure embankment failure

Bodily tides near spin-orbit resonances

Spin-orbit coupling can be described in two approaches. The method known as "the MacDonald torque" is often combined with an assumption that the quality factor Q is frequency-independent. This makes the method inconsistent, because the MacDonald theory tacitly fixes the rheology by making Q scale as the inverse tidal frequency. Spin-orbit coupling can be treated also in an approach called "the Darwin torque". While this theory is general enough to accommodate an arbitrary frequency-dependence of Q, this advantage has not yet been exploited in the literature, where Q is assumed constant or is set to scale as inverse tidal frequency, the latter assertion making the Darwin torque equivalent to a corrected version of the MacDonald torque. However neither a constant nor an inverse-frequency Q reflect the properties of realistic mantles and crusts, because the actual frequency-dependence is more complex. Hence the necessity to enrich the theory of spin-orbit interaction with the right frequency-dependence. We accomplish this programme for the Darwin-torque-based model near resonances. We derive the frequency-dependence of the tidal torque from the first principles, i.e., from the expression for the mantle's compliance in the time domain. We also explain that the tidal torque includes not only the secular part, but also an oscillating part. We demonstrate that the lmpq term of the Darwin-Kaula expansion for the tidal torque smoothly goes through zero, when the secondary traverses the lmpq resonance (e.g., the principal tidal torque smoothly goes through nil as the secondary crosses the synchronous orbit). We also offer a possible explanation for the unexpected frequency-dependence of the tidal dissipation rate in the Moon, discovered by LLR