Braid invariants for non-linear differential equations

Vorst, R.C.A.M. van der [Promotor]Berg, G.J.B. van den [Promotor

Approximate solution to a hybrid model with stochastic volatility: a singular-perturbation strategy

We study a hybrid model of Sch¨obel-Zhu-Hull-White-type from a singular-perturbationanalysis perspective. The merit of the paper is twofold: On one hand, we find boundary conditions for the deterministic non-linear degenerate parabolic partial differential equation for the evolution of the stock price. On the other hand, we combine two-scales regular- and singular-perturbation techniques to find an approximate solution to the pricing PDE. The aim is to produce an expression that can be evaluated numerically very fast

1/3 magnetization plateau and frustrated ferrimagnetism in a sodium iron phosphite

AT was supported by the Federal Ministry for Education and Research through the Sofja Kovalevskaya Award of Alexander von Humboldt Foundation. This work was supported in part by Russian Foundation for Basic Research grants 14-02-00111, 14-02-00245, 16-02-00021, from the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (№ К2-2015-075 and № K4-2015-020) and by Act 211 of the Government of Russian Federation, agreement № 02.A03.21.0006. EAZ, JW and RK acknowledge support by the Excellence Initiative of the German Federal Government and States. PL thanks EPSRC (EP/K503162/1) for partial support of a studentship to IM and the Leverhulme Trust for the award of a post-doctoral fellowship (RPG-2013-343) to LC. SK is grateful for the funding by SSP1458 of the DFG.The sodium-iron phosphite NaFe3(HPO3)2(H2PO3)6 is studied by ac-magnetic susceptibility, pulsed-field magnetization, specific heat, and high-frequency electron spin resonance (HF-ESR) measurements combined with Mössbauer spectroscopy and density-functional calculations. We show that this compound develops ferrimagnetic order below TC = 9.5 K and reveals a magnetization plateau at 1/3-saturation. The plateau extends to Bc ~ 8 T, whereas above Bc the magnetization increases linearly until reaching saturation at Bs ~ 27 T. The Mössbauer spectroscopy reveals two magnetically non-equivalent iron sites with the 2:1 ratio. The HF-ESR spectra are consistent with a two-sublattice ferrimagnet and additionally pinpoint weak magnetic anisotropy as well as short-range spin order that persists well above TC. The ferrimagnetic order in the title compound is stabilized by a network of purely antiferromagnetic exchange interactions. The spin lattice comprises layers coinciding with the crystallographic (10-1) planes, with stronger couplings Ji ~ 1.5 K within the layers and weaker couplings Ji = 0.3−0.4 K between the layers. Both intralayer and interlayer couplings are frustrated. The ensuing ferrimagnetic order arises from a subtle interplay of the frustrated but nonequivalent exchange couplings.PostprintPostprintPeer reviewe

In Memoriam: Obituary of David Goss

International audienc

Libraries in post primary schools Guidelines for good practice

SIGLEAvailable from British Library Document Supply Centre-DSC:98/18089 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Messina. Dal “degrado pianificato” delle periferie alla “periferizzazione” della città

Il saggio riassume il processo di costruzione e il progressivo degrado delle periferie messinesi, sottolineando come il disagio sociale ed il degrado urbanistico ed edilizio piuttosto che essere un effetto imprevisto e perverso della costruzione della città, sia un esito (prevedibile e scontato) di errate politiche urbane, scarsa rilevanza attribuita agli strumenti urbanistici ed una ferma volontà politica di non governare i processi territoriali

Aortic endograft and bridging stent-graft remodeling after branched endovascular aortic repair

Objectives: The results of branched endovascular repair of thoracoabdominal aneurysms are mainly dependent on durability of the graft used. The purpose of this study was to evaluate postoperative aortic main body and bridging stent-graft remodeling, and their impact on bridging stent-graft instability at one year. Methods: Computed tomoangiographies of 43 patients (43 aortic main body mated with 171 bridging stent-grafts) were analyzed before and after branched endovascular repair as well as after a follow-up of 12 months. Primary endpoint was aortic main body remodeling (migration >5 mm, shortening >5 mm, scoliosis >5° or lordosis >5°). Shortening was defined as a reduced length in the long axis, scoliosis as left-right curvature, and lordosis as antero-posterior curvature. Aortic main body remodeling, aneurysm sac changes, and bridging stent-graft tortuosity were evaluated to study their correlations and the impact on the bridging stent-graft instability. Results: At 12 months, aortic main body remodeling was observed in 72% of the cases, migration in 39.5% (mean 5.21 mm), shortening in 41.9% (mean 5.79 mm), scoliosis in 58.1%, (mean 10.10°), lordosis in 44.2% (mean 5.78°). Migration, shortening, and scoliosis were more frequent in patients with larger aneurysms (p =.005), while scoliosis was significantly more frequent in type II thoracoabdominal aneurysm (p =.019). Aortic main body remodeling was significantly associated to bridging stent-graft remodeling (r: 0.3–0.48). The bridging stent-graft instability rate was 9.3%. Despite a trend toward significance (p =.07), none of the evaluated aortic main body and bridging stent-graft changes were associated with bridging stent-graft instability at 12 months. Conclusions: Aortic main body remodeling is frequent especially in large and extended thoracoabdominal aneurysm aneurysms. Aortic main body and bridging stent-graft remodeling was significantly correlated. While these geometric changes had no significant impact on bridging stent-graft instability at one year, a close long-term follow-up after branched endovascular repair could predict bridging stent-graft failures