UV background fluctuations traced by metal ions at z≈3z\approx3

Here we investigate how LyC-opaque systems present in the intergalactic medium at $z\approx3$ can distort the spectral shape of a uniform UV background (UVB) through radiative transfer (RT) effects. With this aim in mind, we perform a multi-frequency RT simulation through a cosmic volume of $10h^{-1}$~cMpc scale polluted by metals, and self-consistently derive the ions of all the species. The UVB spatial fluctuations are traced by the ratio of He$\, \rm \scriptstyle II\$ and H$\, \rm \scriptstyle I\$ column density, $\eta$, and the ratio of C$\,{\rm {\scriptstyle IV\ }}$ and Si$\,{\rm {\scriptstyle IV\ }}$ optical depths, $\zeta$. We find that: (i) $\eta$ spatially fluctuates through over-dense systems ($\Delta$) with statistically significant deviations $\delta\eta >25$\% in 18\% of the volume ; (ii) same fluctuations in $\zeta$ are also present in $34$\% of the enriched domain (only 8\% of the total volume) and derive from a combination of RT induced effects and in-homogeneous metal enrichment, both effective in systems with $\Delta > 1.5$.Comment: Accepted for pub. in MNRAS after very minor re

Ultrasonic distance sensor improvement using a two-level neural network

This paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of an ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance uncertainty (rms) of less than 0.5 mm over 0.5 m by using a two-level neural network to process the US echo and determine the TOF in the presence of environmental acoustic noise. The network embeds a "guard" neuron that guards against gross measurement errors, which would be possible in the presence of high environmental noise

Ultrasonic distance sensor improvement using a two-level neural network

This paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of an ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance uncertainty (rms) of less than 0.5 mm over 0.5 m by using a two-level neural network to process the US echo and determine the TOF in the presence of environmental acoustic noise. The network embeds a "guard" neuron that guards against gross measurement errors, which would be possible in the presence of high environmental noise

Crystal structure of bis(1-phenylimidazolium) tetrachlorocuprate(II), (C9H9N2)2(CuCl4)

AbstractC18H18Cl4CuN4, monoclinic, C121 (No. 5), a = 14.109(3) Å, b = 10.263(2) Å, c = 15.290(3) Å, β = 102.61(3)°, V = 2160.6Å3, Z = 4, Rgt(F) = 0.040, wRall(F2) = 0.124, T = 293 K

Ultrastructural changes of collagen and elastin in human gingiva during orthodontic tooth movement

After 15 days of mesializing or distalizing orthodontic treatment, 10 permanent premolars of young patients were extracted with the interdental gingiva. The connective tissues of the compressed or stretched interdental papillae were compared to that of untreated samples by light and transmission electron microscope.Large collagen fibres bundles represented by fibrils with a banding pattern of 64 nm and a mean diameter of 75 nm were observed in compressed interdental gingiva. Several elastic fibres with a mean diameter of 950 nm were also present. In some central areas of compressed gingiva collagen fibrils longitudinally split into widely spaced microfibrils were often observed in proximity to the elastic fibres.In stretched and untreated interdental papillae the collagen fibrils presented a mean diameter of 66 nm and 57 nm respectively. In both groups, few elastic fibres ranging in diameter 600 nm were seen. The increased size of the gingival collagen fibrils undergoing pressure and tension is indicative of remodelling of the fibrous collagen system.The fair increase in number and size of elastic fibres in compressed gingiva suggests that the elastic fibre system takes over the place whenever a collapse of the collagenous framework occurs.Après 15 jours de traitement orthodontique par mésialisation ou distalisation, 10 prémolaires permanentes ont été extraites chez de jeunes patients, ainsi que la gencive interdentaire adjacente. Le tissu conjonctif des papilles interdentaires comprimées ou étirées a été comparé avec celui d’échantillons de dents n’ayant pas subi de traitement. L’observation a été faite en microscopie classique et en microscopie électronique à transmission. Dans la gencive interdentaire comprimée, on observe de longs faisceaux de fibres de collagène faits de fibrilles qui présentent une périodicité de 64 nm et un diamètre inférieur à 75 nm. Ont été observées également de fibres élastiques d’une diamètre inférieur à 950 nm. Dans certaines zones centrales de gencive comprimée, on peut voir, à proximité dess fibres élastiques, des fibrilles de collagène réparties longitudinalement en microfibrilles très espacées.Dans la gencive interdentaire étirée et dans celle non soumise au traitement orthodontique, les fibrilles de collagène présentent un diamètre de 66 nm et 57 nm respectivement. Dans ces deux groupes, on note un très petit nombre de fibres élastiques de 600 nm de diamètre. L’augmentation du nombre et de la taille des fibres élastiques dans la gencive comprimée indique que le système de fibres élastiques remplace la trame collagène qui a subi un collapsus

Crystal structure of {2-[4-(4-chlorophenyl)-4-hydroxy-l-piperidinylmethyl] cyclopentyl}-(4-fluorophenyl)-methanone, C24H27CIFNO2

Abstract C24H27ClFNO2, triclinic, P1̅̅̅̅ (No. 2), a = 9.494(2) Å, b = 10.769(2) Å, c = 11.377(3)Å, α = 87.18(3)°, β = 67.27(3)°, γ = 88.01(3)°, V = 1071.4 Å3, Z = 2, Rgt(F) = 0.076, wRobs(F2) = 0.302, T = 293 K