High-resolution synchrotron XRD study of Zr-rich compositions of Pb(Zr_xTi_1-x)O_3 (0.525\leq x \leq 0.60): evidence for the absence of the rhombohedral phase

Results of Rietveld analysis of the synchrotron XRD data on Pb(Zr_xTi_1-x)O_3 (PZT) for 0.525\leqx\leq0.60 are presented to show the absence of rhombohedral phase on the Zr-rich side of the morphotropic phase boundary (MPB). Our results reveal that the structure of PZT is monoclinic in the Cm space group for 0.525\leq x\leq 0.60. The nature of the monoclinic distortion changes from pseudo-tetragonal for 0.525\leqx\leq0.54 to pseudo-rhombohedral for x>0.54.Comment: 12 pages, 5 figur

Exponential torsion growth for random 3-manifolds

We show that a random 3-manifold with positive first Betti number admits a tower of cyclic covers with exponential torsion growth

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

Managerial Ability and the Quality of Firms’ Information Environment

In this study, we examine the relation between managerial ability and the quality of a firm’s information environment. An emerging stream of research has identified managerial ability as an important determinant of accruals quality and management forecast quality. However, our understanding of the impact of managerial ability on a firm’s broader information environment is incomplete because it captures more than these specific financial reporting disclosures. Using a composite index based on various proxies for a firm’s information environment, we find a positive relation between managerial ability and a firm’s information environment. Consistent with our argument that managers’ equity incentives improve disclosure quality, we find that the quality of a firm’s information environment improves when managers have higher levels of equity incentives. We contribute to the literature by providing more complete and conclusive evidence about the impact of managerial ability on a firm’s broader information environment

Geospatial analysis of BECCS deployment potential in the U.S.

Negative emissions from bioenergy with carbon capture and storage (BECCS) has been identified as a potentially important carbon mitigation technology. To date, much of the technical work and discussion on BECCS have focused on land use change and bioenergy potential, while the CCS components – including capacity, injectivity, and location of potential storage sites – have been overlooked. A geospatial analysis of biomass production and storage sites in the U.S. is conducted to discuss BECCS deployment in the U.S. across a range of biomass production scenarios. U.S. Department of Energy provides national annual biomass production data from 2015 to 2040. Extrapolating the production trends across different yield scenarios to 2100 shows average annual CO2 production from agricultural residue and energy crop of 720-1,220 Mt CO2 yr-1 and cumulative production of 27-47 Gt CO2. Considering that the estimated storage capacity in the U.S. is ~3,000 Gt CO2, absolute storage capacity is not likely to be a constraint on BECCS. However, collocation of high-density biomass (\u3e25 MW per 100×100 km2) and high injection rate storage sites (\u3e5 Mt CO2 yr-1) in 2040 yields biomass CO2 injection potential of 140-360 Mt CO2 yr-1. This represents 9-39% of the total biomass feedstock in the U.S. To achieve a biomass CO2 injection potential greater than 360 Mt CO2 yr-1, transportation networks of either biomass or CO2 will be needed. The geospatial analysis conducted in this study highlights the importance of previously overlooked CCS components in global BECCS assessments and provides a framework for future studies. Please click Additional Files below to see the full abstract

Expected length of the longest common subsequence for large alphabets

We consider the length L of the longest common subsequence of two randomly uniformly and independently chosen n character words over a k-ary alphabet. Subadditivity arguments yield that the expected value of L, when normalized by n, converges to a constant C_k. We prove a conjecture of Sankoff and Mainville from the early 80's claiming that C_k\sqrt{k} goes to 2 as k goes to infinity.Comment: 14 pages, 1 figure, LaTe

Genetic Classification of Populations using Supervised Learning

There are many instances in genetics in which we wish to determine whether two candidate populations are distinguishable on the basis of their genetic structure. Examples include populations which are geographically separated, case--control studies and quality control (when participants in a study have been genotyped at different laboratories). This latter application is of particular importance in the era of large scale genome wide association studies, when collections of individuals genotyped at different locations are being merged to provide increased power. The traditional method for detecting structure within a population is some form of exploratory technique such as principal components analysis. Such methods, which do not utilise our prior knowledge of the membership of the candidate populations. are termed \emph{unsupervised}. Supervised methods, on the other hand are able to utilise this prior knowledge when it is available. In this paper we demonstrate that in such cases modern supervised approaches are a more appropriate tool for detecting genetic differences between populations. We apply two such methods, (neural networks and support vector machines) to the classification of three populations (two from Scotland and one from Bulgaria). The sensitivity exhibited by both these methods is considerably higher than that attained by principal components analysis and in fact comfortably exceeds a recently conjectured theoretical limit on the sensitivity of unsupervised methods. In particular, our methods can distinguish between the two Scottish populations, where principal components analysis cannot. We suggest, on the basis of our results that a supervised learning approach should be the method of choice when classifying individuals into pre-defined populations, particularly in quality control for large scale genome wide association studies.Comment: Accepted PLOS On

Anti-inflammatory effect of low intensity ultrasound (LIUS) on complete Freund's adjuvant-induced arthritis synovium

SummaryObjectivesArthritis with intra-articular inflammation was accompanied by joint pain, swelling, and stiffness leading to significant functional impairment. Thus, regulation of joint inflammation is a good therapeutic approach for patients with arthritis. In this study, the effect of low intensity ultrasound (LIUS) applied to an adjuvant-induced arthritic rat model on the synovium was investigated.DesignSynovial inflammation was induced by complete Freund's adjuvant (CFA)-injection into the rat knee joint. LIUS (200 mW/cm2) was applied on the ipsilateral knee everyday for 10 min beginning 1 day after inflammation induction. The expression of proinflammatory factors and immunohistochemical staining pattern of the synovium were assessed.ResultsCFA induced an increase of the knee circumference that was significantly diminished by LIUS. Synovial membrane hyperplasia in the ipsilateral joint was also affected by LIUS. The inflammatory mediators, COX-1/2, IL-1β, and iNOS, but not TNF-α, in the synovial membrane were induced after 3 days, and they closely correlated with the degree of edema. In the synovial membrane, the expression of inflammatory mediators was reduced by LIUS. The chemoattractant chemokine receptor CCR5 also was involved. On immunohistochemical analysis, CFA caused increased infiltration of CD11b-positive cells in the synovium. After 3 days, neutrophils, myeloperoxidase (MPO)-positive cells filled the inflammatory core; later, monocytes and macrophages, ionized calcium binding adaptor molecule 1 (Iba1)-positive cells in the periphery infiltrated the core by day 5. LIUS markedly reduced CFA-induced inflammatory cells infiltration.ConclusionLIUS showed a potent anti-inflammatory effect in this animal arthritis model with reduced infiltration of inflammatory cells into the synovium

Airy processes and variational problems

We review the Airy processes; their formulation and how they are conjectured to govern the large time, large distance spatial fluctuations of one dimensional random growth models. We also describe formulas which express the probabilities that they lie below a given curve as Fredholm determinants of certain boundary value operators, and the several applications of these formulas to variational problems involving Airy processes that arise in physical problems, as well as to their local behaviour.Comment: Minor corrections. 41 pages, 4 figures. To appear as chapter in "PASI Proceedings: Topics in percolative and disordered systems