Model Inference with Reference Priors

We describe the application of model inference based on reference priors to two concrete examples in high energy physics: the determination of the CKM matrix parameters rhobar and etabar and the determination of the parameters m_0 and m_1/2 in a simplified version of the CMSSM SUSY model. We show how a 1-dimensional reference posterior can be mapped to the n-dimensional (n-D) parameter space of the given class of models, under a minimal set of conditions on the n-D function. This reference-based function can be used as a prior for the next iteration of inference, using Bayes' theorem recursively.Comment: Proceedings of PHYSTAT1

The structure of a minimal nn-chart with two crossings II: Neighbourhoods of Γ1∪Γn−1\Gamma_1\cup\Gamma_{n-1}

Given a 2-crossing minimal chart $\Gamma$, a minimal chart with two crossings, set $\alpha=\min\{~i~|~$there exists an edge of label $i$ containing a white vertex$\}$, and $\beta=\max\{~i~|~$there exists an edge of label $i$ containing a white vertex$\}$. In this paper we study the structure of a neighbourhood of $\Gamma_\alpha\cup\Gamma_\beta$, and propose a normal form for 2-crossing minimal $n$-charts, here $\Gamma_\alpha$ and $\Gamma_\beta$ mean the union of all the edges of label $\alpha$ and $\beta$ respectively.Comment: 57 pages, 36 figure

Different intra- and inter-molecular hydrogen-bonding patterns in (3S,4aS,8aS)-2-[(2R,3S)-3-(2,5-X2-benzamido)-2-(2,5-X2-benzo-yloxy)-4-phenyl-butyl]-N-tert-butyldeca-hydro-iso-quinoline-3-carboxamides (X = H or Cl) : compounds with moderate aspartyl protease inhibition activity

We thank the EPSRC National Crystallography Service (University of Southampton) for the X-ray data collections.Peer reviewedPublisher PD

Fractional Chern insulator on a triangular lattice of strongly correlated t2gt_{2g} electrons

We discuss the low-energy limit of three-orbital Kondo-lattice and Hubbard models describing $t_{2g}$ orbitals on a triangular lattice near half-filling. We analyze how very flat bands with non-trivial topological character, a Chern number C=1, arise both in the limit of infinite on-site interactions as well as in more realistic regimes. Exact diagonalization is then used to investigate fractional filling of an effective one-band spinless-fermion model including nearest-neighbor interaction $V$; it reveals signatures of fractional Chern insulators (FCIs) for several filling fractions. In addition to indications based on energies, e.g. flux insertion and fractional statistics of quasiholes, Chern numbers are obtained. It is shown that FCIs are robust against disorder in the underlying magnetic texture that defines the topological character of the band. We also investigate competition between FCI states and a charge density wave (CDW) and discuss particle-hole asymmetry as well as Fermi-surface nesting. FCI states turn out to be rather robust and do not require very flat bands, but can also arise when filling or an absence of Fermi-surface nesting disfavor the competing CDW. Nevertheless, very flat bands allow FCI states to be induced by weaker interactions than those needed for more dispersive bands.Comment: 14 pages, 13 figure

Efficient and accurate computation of upper bounds of approximation errors

International audienceFor purposes of actual evaluation, mathematical functions f are commonly replaced by approximation polynomials p. Examples include floating-point implementations of elementary functions, quadrature or more theoretical proof work involving transcendental functions. Replacing f by p induces a relative error epsilon = p/f - 1. In order to ensure the validity of the use of p instead of f, the maximum error, i.e. the supremum norm of epsilon must be safely bounded above. Numerical algorithms for supremum norms are efficient but cannot offer the required safety. Previous validated approaches often require tedious manual intervention. If they are automated, they have several drawbacks, such as the lack of quality guarantees. In this article a novel, automated supremum norm algorithm with a priori quality is proposed. It focuses on the validation step and paves the way for formally certified supremum norms. Key elements are the use of intermediate approximation polynomials with bounded approximation error and a non-negativity test based on a sum-of-squares expression of polynomials. The new algorithm was implemented in the Sollya tool. The article includes experimental results on real-life examples

Morphological and Chemical Characterisation of Indoor Quasi-Ultrafine Particles

Particles in the nanoscale range have intrinsic physicochemical characteristics that define their interaction with the human body and ultimately their toxicity. Whilst research has focused on engineered nanomaterials or ambient ultrafine particles, little is known about the morphology, size and elemental composition of particles in the nanoscale range collected in indoor environments, where humans spend the longest time. This study aims to characterise the physicochemical properties of quasi-ultrafine particles (qUFP), with an aerodynamic diameter <250 nm, collected with a Sioutas impactor from 5 indoor environments (3 homes and 2 offices). Morphology, size and elemental composition of individual particles were imaged using a Transmission Electron Microscope coupled with X-ray energy dispersive spectroscopy. Most of the single particles and their aggregates were of irregular shapes, and some fibrous rods, elongated rods, spheres and hexagons were also observed. ImageJ software was used to analyse the surface area, roundness and circularity of the particles, as well as individual particle diameter for the spherical particles. For the non-spherical shaped particle, the particles were manually measured to characterise the maximum Feret diameter. Particle main dimensions (i.e. diameter for spheroids and maximum Feret diameter for irregular particles) ranged from 35 ± 59 nm to 103 ± 160 nm. Shapes for non-spherical particles were assigned by visual description. Si, Fe and S were found in nanoparticles from all indoor locations. Other abundant constituents were K, Cr, Na, Ca, Cl found in 60–80% of locations. Minor constituents of indoor nanoparticles were Cu, Sn, Ti, Mo, Al, P, Be, F, Zn, Rb, Pb, Mn and Co. Sources were related to indoor emissions, e.g. printers, stainless-steel tools, electronics, cooking, house chores, particle re-suspension, aerosol and cleaning products as well as to penetration of outdoor nanoparticles from vehicular emissions, soil and secondary aerosols. Detailed investigation of the physicochemical properties of these particles can help understand their associated hazard and their fate in the human body

Diageo Strategic Audit: A Deep Dive into the Management Strategies of Diageo

Diageo is a multinational premium drink producer and supplier with over 200 brands and sales in over 180 countries. A conglomerate since its founding, Diageo controls and operates some of the world’s well-known and loved drinks, like Guinness, Johnnie Walker, Smirnoff, Bailey’s, Captain Morgan, and Crown Royal. The firm is an industry leader in consumer insight, innovation and creativity, and sustainability efforts. Diageo believes pursuing sustainability, efficiency, and positive drinking allows them to compete, now and in the future. This audit analyzes the history, leadership, business model, mission, external environment, internal environment, core competencies, recent performance, competitive dynamics, business level strategies, corporate level strategies, merger/acquisition strategies, corporate governance, and organizational controls of Diageo. The combination of ethical, innovative, and sustainable management strategies across all of these areas paints a vivid picture that explains the decades of success Diageo has had and continues to have in a fast-paced and ever-changing industry