Heavy-tailed distributions of meme popularity occur naturally in a model diffusion on social networks. Competition between multiple memes for the limited resource user attention is identified as mechanism that poises system at criticality. The growth each described by critical branching process, and asymptotic analysis predicts power-law with very heavy tails (exponent $\ensuremath{\alpha}<2$, unlike preferential-attachment models), similar to those seen empirical data.

The impact of a pharmacist-physician collaborative care model on patient outcomes and health services utilization is described.Six hospitals from the Carilion Clinic system in southwest Virginia, along with 22 patient-centered medical home (PCMH) practices affiliated Clinic, participated this project. Eligibility criteria included documented diagnosis 2 or more 7 targeted chronic conditions (congestive heart failure, hypertension, hyperlipidemia, diabetes mellitus, asthma, obstructive...

In espresso brewing, soluble content is extracted from a bed of ground coffee beans by forcing hot water through the at high pressure. An important part this process infiltration stage in which permeates initially dry bed. This investigated combination x-ray tomography and fluid mechanical modeling. Tomography used to track front via contrast density. The experimental data are compared with one-dimensional unsaturated porous medium flow model, divides into wet regions incorporates pump...

Even in a topologically perfect crystal, moving twin wall will experience forces due to the discrete nature of lattice. The potential energy landscape can be described terms one two parameters: Peierls energy, which is activation for domain motion crystal; and stress, maximum pinning stress that exert. We investigate these parameters order parameter Landau-Ginzburg model classical ferroelastic perovskite CaTiO3. Using we show scales with barrier height Landau double well calculate its...

The binding and pairwise interaction of oxygen vacancies in the ferroelastic (100) twin walls orthorhombic phase ${\text{CaTiO}}_{3}$ perovskite $(Pbnm)$ have been investigated by numerical simulations using empirical force fields. An vacancy finds it energetically favorable to reside inside a wall, particularly when bridging two titanium ions located twin-wall plane. In such case, energy wall is $0.7\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{eV}$, error bar reflecting variability within...

The extraction of coffee solubles from roasted and ground is a complex operation, the understanding which key to brewing high quality coffee. This complexity stems fact that achieved through wide variety techniques each depends on large number process variables. In this paper, we consider recent, experimentally validated model extraction, describes bed using double porosity model. incorporates dissolution transport in bed. was shown accurately describe grains two situations: dilute...

Landau-type theories describe the observed behaviour of phase transitions in ferroelastic and co-elastic minerals materials with a high degree accuracy. In this review, derivation Landau potential G=1/2AthetaS [coth(thetaS/T)-coth(thetaS/TC)]Q2 + 1/4BQ4 ... is derived as solution general phi4 model. The coupling between order parameter spontaneous strain transition brings many to mean-field limit, even when atomistic mechanism spin-like. Strain also common for multiple parameters single...

Recent experimental work has shown that, when a vertical column of rock under large pressure is suddenly depressurized, the can ‘explode’ in structured and repeatable way. The observations show that sequence horizontal fractures forms from top down, resulting blocks are lifted off ejected. suffer secondary internal fractures. This experiment provides framework for understanding way which catastrophic explosion occur, motivated by corresponding phenomenon magmatic during Vulcanian eruptions....

A recent experimental measurement of the width a twin wall suggests that can vary considerably as function position. This contradicts previously held assumption was constant, taking same value in adjacent walls and different parts wall. We explore possibility this variation is result interaction order parameter with point defects. do context two-dimensional model on square grid which continuous interacts lattice Ising spins representing presence or absence show key to reproducing...

Bubble nucleation in weakly supersaturated solutions of carbon dioxide---such as champagne, sparkling wines, and carbonated beers---is well understood. Bubbles grow detach from sites: gas pockets trapped within hollow cellulose fibers. This mechanism appears not to be active stout beers that are nitrogen dioxide. In their canned forms these require additional technology (widgets) release the bubbles which will form head beer. We extend mathematical model bubble liquids case two gases show...

A recent experiment showed that, contrary to theoretical predictions, beyond a cutoff point grinding coffee more finely results in lower extraction. One potential explanation for this is that fine promotes non-uniform extraction the bed. We investigate possibility could occur due interaction between dissolution and flow promoting uneven low dimensional model which there are two possible pathways derived analysed. This shows below critical grind size, decreasing with size as seen...

Commonly-employed Feed-in Tariff (FiT) structures result in either investors or policymakers incurring all market price risk. This paper derives efficient pricing formulae for FiT designs that divide risk amongst and policymakers. With increasing deployment renewable energy policy costs, a means to precisely apportion this becomes of greater importance. Option theory is used calculate prices expected cost when are exposed elements Expected remuneration equal FiTs while policymaker investor...

Relaxation processes due to two opposite surfaces in a slab of hydroxyapatite with (100) free are reported. Interatomic potentials for hydroxyapatite, chloroapatite and fluoroapatite were refined using elastic vibrational data. Systems relaxed. It was found that the relaxation which occurred at surface included polarization layers close surface, distortion channels hydroxide ions sit tetrahedral phosphate ions. Some these relaxations only occur unit cells closest surface; others persist few...

Extraction of coffee solubles from roast and ground is a highly complex process, depending on large number brewing parameters. We consider recent, experimentally validated, model extraction, describing extraction bed using double porosity model, which includes dissolution transport coffee. It was shown that this can accurately describe in two situations: dilute suspension grains packed bed. Despite being based some simplifying assumptions, only be solved numerically. In paper we asymptotic...

Achieving a uniform extraction of soluble material from porous matrix is generic problem in various separation and filtration operations, with applications the food processing, chemical pharmaceutical industries. This paper describes models fluid flow transport within packed granular bed context coffee extraction. Coffee described by diffusion particles one or more representative sizes into flowing through bed. One-dimensional are compared to computational dynamics (CFD) models. A fine...

The dynamics of transformation twins in ${\mathrm{Sr}}_{x}{\mathrm{Ba}}_{1\ensuremath{-}x}\mathrm{Sn}{\mathrm{O}}_{3}$ $(x=0.6,0.8)$ perovskite has been studied by dynamical mechanical analysis three-point bend geometry. This material undergoes phase transitions from orthorhombic to tetragonal and cubic structures on heating. loss signatures the include relaxation frequency-independent peaks orthorhombic, phases, with no observed energy dissipation phase. macroscopic shape, orientation,...

We review the differences between bubble formation in champagne and other carbonated drinks, stout beers which contain a mixture of dissolved nitrogen carbon dioxide. The presence gives them several properties interest to connoisseurs physicists. These remarkable come at price: do not foam spontaneously special technology, such as widgets used cans, is needed promote foaming. Nevertheless, same mechanism, nucleation by gas pockets trapped cellulose fibers, responsible for foaming drinks...

Abdominal aortic aneurysm disease progression is probably influenced by tissue stresses and blood flow conditions so accurate estimation of these will increase understanding the may lead to improved clinical practice. In this work in axially symmetric aneurysms are calculated using a complete fluid—structure interaction as benchmark for calculating error introduced simpler calculations: rigid walled flow, homogeneous pressure stress, well one-way-coupled interactions. The peak von Mises...