Killing vectors and anisotropy

We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string

Thulium and ytterbium-doped titanium oxide thin films deposited by ultrasonic spray pyrolysis

Thin films of thulium and ytterbium-doped titanium oxide were grown by metal-organic spray pyrolysis deposition from titanium(IV)oxide bis(acetylacetonate), thulium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and ytterbium(III) tris(acetylacetonate). Deposition temperatures have been investigated from 300{\deg}C to 600{\deg}C. Films have been studied regarding their crystallity and doping quality. Structural and composition characterisations of TiO2:Tm,Yb were performed by electron microprobe, X-ray diffraction and Fourier transform infrared spectroscopy. The deposition rate can reach 0.8 \mum/h. The anatase phase of TiO2 was obtained after synthesis at 400{\deg}C or higher. Organic contamination at low deposition temperature is eliminated by annealing treatments.Comment: 6 pages, 6 figure

Effects of omega-3 fatty acids on arterial stiffness in patients with hypertension: a randomized pilot study.

BackgroundOmega-3 fatty acids prevent cardiovascular disease (CVD) events in patients with myocardial infarction or heart failure. Benefits in patients without overt CVD have not been demonstrated, though most studies did not use treatment doses (3.36 g) of omega-3 fatty acids. Arterial stiffness measured by pulse wave velocity (PWV) predicts CVD events independent of standard risk factors. However, no therapy has been shown to reduce PWV in a blood pressure-independent manner. We assessed the effects of esterified omega-3 fatty acids on PWV and serum markers of inflammation among patients with hypertension.Design and methodsWe performed a prospective, randomized; double-blinded pilot study of omega-3 fatty acids among 62 patients in an urban, safety net hospital. Patients received 3.36 g of omega-3 fatty acids vs. matched placebo daily for 3-months. The principal outcome measure was change in brachial-ankle PWV. Serum inflammatory markers associated with CVD risk were also assessed.ResultsThe majority (71 %) were of Latino ethnicity. After 3-months, mean change in arterial PWV among omega-3 and placebo groups was -97 cm/s vs. -33 cm/s respectively (p = 0.36 for difference, after multivariate adjustment for baseline age, systolic blood pressure, and serum adiponectin). Non-significant reductions in lipoprotein-associated phospholipase A2 (LpPLA2) mass and high sensitivity C-reactive protein (hsCRP) relative to placebo were also observed (p = 0.08, and 0.21, respectively).ConclusionHigh-dose omega-3 fatty acids did not reduce arterial PWV or markers of inflammation among patients within a Latino-predominant population with hypertension.Clinical trial registrationNCT00935766 , registered July 8 2009

Electrostatically confined Quantum Rings in bilayer Graphene

We propose a new system where electron and hole states are electrostatically confined into a quantum ring in bilayer graphene. These structures can be created by tuning the gap of the graphene bilayer using nanostructured gates or by position-dependent doping. The energy levels have a magnetic field ($B_{0}$) dependence that is strikingly distinct from that of usual semiconductor quantum rings. In particular, the eigenvalues are not invariant under a $B_0 \to -B_0$ transformation and, for a fixed total angular momentum index $m$, their field dependence is not parabolic, but displays two minima separated by a saddle point. The spectra also display several anti-crossings, which arise due to the overlap of gate-confined and magnetically-confined states.Comment: 5 pages, 6 figures, to appear in Nano Letter