Thermodynamic constraints on the amplitude of quantum oscillations

Magneto-quantum oscillation experiments in high temperature superconductors show a strong thermally-induced suppression of the oscillation amplitude approaching critical dopings---in support of a quantum critical origin of their phase diagrams. We suggest that, in addition to a thermodynamic mass enhancement, these experiments may directly indicate the increasing role of quantum fluctuations that suppress the oscillation amplitude through inelastic scattering. We show that the traditional theoretical approaches beyond Lifshitz-Kosevich to calculate the oscillation amplitude in correlated metals result in a contradiction with the third law of thermodynamics and suggest a way to rectify this problem.Comment: PRB Rapid commun. (2017

Non-unique factorization of polynomials over residue class rings of the integers

We investigate non-unique factorization of polynomials in Z_{p^n}[x] into irreducibles. As a Noetherian ring whose zero-divisors are contained in the Jacobson radical, Z_{p^n}[x] is atomic. We reduce the question of factoring arbitrary non-zero polynomials into irreducibles to the problem of factoring monic polynomials into monic irreducibles. The multiplicative monoid of monic polynomials of Z_{p^n}[x] is a direct sum of monoids corresponding to irreducible polynomials in Z_p[x], and we show that each of these monoids has infinite elasticity. Moreover, for every positive integer m, there exists in each of these monoids a product of 2 irreducibles that can also be represented as a product of m irreducibles.Comment: 11 page

The genetic architecture of emerging fungicide resistance in populations of a global wheat pathogen

Containing fungal diseases often depends on the application of fungicidal compounds. Fungicides can rapidly lose effectiveness due to the rise of resistant individuals in populations. However, the lack of knowledge about resistance mutations beyond known target genes challenges investigations into pathways to resistance. We used whole-genome sequencing data and association mapping to reveal the multilocus genetic architecture of fungicide resistance in a global panel of 159 isolates of Parastagonospora nodorum, an important fungal pathogen of wheat. We found significant differences in azole resistance among global field populations. The populations evolved distinctive combinations of resistance alleles which can interact when co-occurring in the same genetic background. We identified 34 significantly associated single nucleotide polymorphisms located in close proximity to genes associated with fungicide resistance in other fungi, including a major facilitator superfamily transporter. Using fungal colony growth rates and melanin production at different temperatures as fitness proxies, we found no evidence that resistance was constrained by genetic trade-offs. Our study demonstrates how genome-wide association studies of a global collection of pathogen strains can recapitulate the emergence of fungicide resistance. The distinct complement of resistance mutations found among populations illustrates how the evolutionary trajectory of fungicide adaptation can be complex and challenging to predict

Jovian protons and electrons: Pioneer 11

A preliminary account of the Pioneer 11 passage through the Jovian magnetosphere as viewed by particle detector systems is presented. Emphasis is placed on the region well within the Jovian magnetosphere using data from the LET-II telescope, which measured the proton flux from 0.2 to 21.2 MeV in seven energy intervals and electrons from 0.1 to 2 MeV in four energy intervals. The relative trajectories of Pioneer 10 and 11 are discussed and indicate that Pioneer 11 was exposed to a much lower total radiation dose than Pioneer 10, largely as a result of the retrograde trajectory which approached and exited the inner region of the magnetosphere at high latitudes. Angular distributions, calculations from Pioneer 11 magnetic field data, and the low-energy nucleon component are included in the discussion

Preliminary Results of a Statistical Analysis of a Long-Term Limnological Study of The Coralville Reservoir

The Coralville Reservoir, located on the Iowa River upstream from Iowa City, has been the subject of an intensive limnological study for the past five years. Interpretation of the physical, chemical and biological data obtained was difficult due to the large numbers of parameters measured and the frequency of sampling. The application of various statistical methods was undertaken in order to aid in analysis of the data. Preliminary correlation analyses yielded some meaningful correlations but had severe limitations. Auto-covariance and auto-correlation analysis for each parameter as well as cross-covariance and correlation tests between a number of parameters yielded useful data on the presence or absence of periodic components. Auto-covariance curves obtained from the study appear to be useful in determining optimal sampling frequency for each parameter

Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBa2_2CuO4+δ_{4+\delta}

High magnetic fields have revealed a surprisingly small Fermi-surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A crucial issue concerns the doping extent of this state and its relationship to the principal pseudogap and superconducting phases. We employ pulsed magnetic field measurements on the cuprate HgBa$_2$CuO$_{4+\delta}$ to identify signatures of Fermi surface reconstruction from a sign change of the Hall effect and a peak in the temperature-dependent planar resistivity. We trace the termination of Fermi-surface reconstruction to two hole concentrations where the superconducting upper critical fields are found to be enhanced. One of these points is associated with the pseudogap end-point near optimal doping. These results connect the Fermi-surface reconstruction to both superconductivity and the pseudogap phenomena.Comment: 5 pages. 3 Figures. PNAS (2020