Density functional theory calculation and thermodynamic analysis of the bridgmanite surface structure

Bridgmanite, a high temperature and pressure form of $MgSiO_3$, is believed to be Earth's most abundant mineral and responsible for the observed seismic anisotropy in the mantle. Little is known about surfaces of bridgmanite but knowledge of the most stable surface terminations is important for understanding various geochemical processes as well as likely slip planes. A density functional theory based thermodynamic approach is used here to establish the range of stability of bridgmanite as well as possible termination structures of the (001), (010), (100) and (011) surfaces as a function of the chemical potential of oxygen and magnesium. The results presented provide a basis for further theoretical studies of the chemical processes on bridgmanite surfaces in the Earth's mantle and slip plane analysis.Comment: 4 Pages,4 figure

Financial indexation and interest rate policy in Iceland

Iceland´s experience of rapid post-war inflation developments prompted a unique experiment with a near-comprehensive financial indexation that may be worthy of consideration for a number of individual countries as well as for international capital markets. The indexation policy came to its full fruition with such an articulated system as from 1979, while credit terms were still administered in detail by the Central Bank. The following period thus became ripe with experiences of running such a system and reaping its benefits. The problem of measurement of inflation was solved by a composite, weighted index of consumer and construction prices, and later to include wages, while finally the preference was for consumer prices alone. This simplification minimized the problem of time lag from measurement to application that had proved considerable under accelerating inflation into higher doule digits. Prior to indexation the stock of financial savings had seriously deteriorated in real and relative terms, mainly due to accumulated effects of negative real interest. With indexation, followed within a few years by free interest formation, the tide was turned over to rapid accumulation of financial capital that soon brought about internal demand equilibrium and restored the role of interest and demand policies in general, as well as greatly improving the external debt position. Bond issues rose to prominence pari passu with indexation with resulting multiplication of market instruments which developed further through share issues and stock exchange operations. The overall achievement has been one of a highly modernized financial system. While thus aiming at protecting the financial system against the ravages of inflation, no illusions were held as to indexation leading to an easy solution of inflation itself. However, it has obviously eliminated the inflation gains of the public at large, and thus stamped out the inflation mentality and substantially eased the task of disinflation.

uFLIP: Understanding Flash IO Patterns

Does the advent of flash devices constitute a radical change for secondary storage? How should database systems adapt to this new form of secondary storage? Before we can answer these questions, we need to fully understand the performance characteristics of flash devices. More specifically, we want to establish what kind of IOs should be favored (or avoided) when designing algorithms and architectures for flash-based systems. In this paper, we focus on flash IO patterns, that capture relevant distribution of IOs in time and space, and our goal is to quantify their performance. We define uFLIP, a benchmark for measuring the response time of flash IO patterns. We also present a benchmarking methodology which takes into account the particular characteristics of flash devices. Finally, we present the results obtained by measuring eleven flash devices, and derive a set of design hints that should drive the development of flash-based systems on current devices.Comment: CIDR 200

Könnun á ástæðu gerðar vistunarmats á LSH

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenInngangur Vistunarmat aldraðra (VMA) er lögformlegt fjórþátta matskerfi, sem tekur til félagslegra þátta, líkamlegs heilsufars, andlegrar líðanar og færniþátta sem þarf að útfylla þegar sótt er um varanlegt vistunarúrræði fyrir aldraða einstaklinga1. Vistunarmatið gildir jafnframt sem umsókn um vistunarúrræði til þeirrar öldrunarstofnunar sem það er sent til. Fyrir fólk í heimahúsi sér þjónustuhópur aldraðra hvers sveitarfélags um að framkvæma matið en sérstakur matshópur fyrir Reykjavík. Fyrir sjúklinga sem ekki komast heim af sjúkrahúsi er vistunarmatið framkvæmt af þverfaglegu teymi; félagsráðgjafa, hjúkrunarfræðingi og sérfræðingi í öldrunarlækningum. Ekki ber að gera vistunarmat fyrr en ljóst er um endanlega færni sjúklings að lokinni fullri endurhæfingu. Algengt er að óskir um að umsókn um vistrými komi frá fleirum en umsækjanda sjálfum. Til þess að heimilt sé að gera vistunarmat þarf skriflega beiðni sem undirrituð er af umsækjanda. Ef hann er ekki fær um að skrifa undir sjálfur, er ætlast til að umboðsaðili hans skrifi undir beiðnina. Ýmsar ástæður, aðrar en fötlun umsækjanda, geta valdið því að sjúklingur er ekki talinn geta útskrifast af sjúkrahúsinu. Í þessari könnun er gerð tilraun til að varpa ljósi á þá þætti sem geta legið að baki gerðar vistunarmatsins

Fast and Robust Algorithm for the Energy Minimization of Spin Systems Applied in an Analysis of High Temperature Spin Configurations in Terms of Skyrmion Density

An algorithm for the minimization of the energy of magnetic systems is presented and applied to the analysis of thermal configurations of a ferromagnet to identify inherent structures, i.e. the nearest local energy minima, as a function of temperature. Over a rather narrow temperature interval, skyrmions appear and reach a high temperature limit for the skyrmion density. In addition, the performance of the algorithm is further demonstrated in a self-consistent field calculation of a skyrmion in an itinerant magnet. The algorithm is based on a geometric approach in which the curvature of the spherical domain is taken into account and as a result the length of the magnetic moments is preserved in every iteration. In the limit of infinitesimal rotations, the minimization path coincides with that obtained using damped spin dynamics while the use of limited-memory quasi-newton minimization algorithms, such as the limited-memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) algorithm, significantly accelerates the convergence