Organic and hydride chemistry of beryllium

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A congestion sensitive approach to modelling road networks for air quality management

This research establishes an approach to modelling a congested road network for air quality management, which enables the assessment of traffic management solutions that may create only subtle changes in the traffic flow regimes. Road network emissions have been calculated using standard factors taking into account details of vehicle fleet composition, average speeds and road type. Additionally, the use of microsimulation traffic modelling in conjunction with an instantaneous emissions model (IEM) has been adopted to allow comparison between methodologies and enable congestion sensitive analysis of the impact of air quality management measures on the network. Findings from microscale modelling have revealed that the use of an IEM to calculate emissions as an input for air quality dispersion modelling significantly improved the performance of the dispersion modelling when measured against monitored data. Moreover, this methodology has been successfully applied to assess the performance of a traffic scheme in Durham, UK

Experimental demonstration of coupled optical springs

Optical rigidity will play an important role in improving the sensitivity of future generations of gravitational wave (GW) interferometers, which employ high laser power in order to reach and exceed the standard quantum limit. Several experiments have demonstrated the combined effect of two optical springs on a single system for very low-weight mirror masses or membranes. In this paper we investigate the complex interactions between multiple optical springs and the surrounding apparatus in a system of comparable dynamics to a large-scale GW detector. Using three 100 g mirrors to form a coupled cavity system capable of sustaining two or more optical springs, we demonstrate a number of different regimes of opto-mechanical rigidity and measurement techniques. Our measurements reveal couplings between each optical spring and the control loops that can affect both the achievable increase in sensitivity and the stability of the system. Hence this work establishes a better understanding of the realisation of these techniques and paves the way to their application in future GW observatories, such as upgrades to Advanced LIGO

Influence of crop rotation and flutolanil on the diversity of fungi on peanut shells

Les agents pathogènes du sol qui affectent les arachides (Arachis hypogaea) survivent ou hivernent souvent sur les écales d'arachides laissées sur ou dans le sol. Les effets de diverses rotations de cultures sur la flore fongique des écales d'arachides ont été comparés par trois tests en champ menés en 1992 et en 1993. Dans deux des tests, les parcelles d'arachides cultivées de façon continue ont été traitées ou non traitées avec le fongicide flutolanil. Les pratiques de rotation ont varié avec la localisation, et les cultures en rotation avec les arachides étaient le coton (Gossypium hirsutum), le seigle (Secale céréale), l'herbe de Bahia (Paspalum notatum), et le maïs (Zea mays). Au total,31 genres de champignon ont été isolés des écales. Plus des deux tiers des isolats étaient des Deutéromycètes, suivis en fréquence par les Basidiomycètes, les Ascomycètes et les Phycomycètes. Les pratiques de rotation ont affecté l'incidence de plusieurs champignons pathogènes (par exemple, les Fusarium spp. et le Lasiodiplodia theobromae) sur les écales d'arachides, mais les résultats n'ont pas été cohérents entre les tests et les années. L'herbe de Bahia ou le maïs cultivés en rotation avec les arachides ont réduit la fréquence du Rhizoctonia solani AG-4 dans les écales. Le Rhizoctonia solani AG-2-2 et le Macrophomina phaseolina ont été isolés à des niveaux plus élevés dans la rotation herbe de Bahia-arachide. Quand les arachides étaient cultivées en rotation avec le coton avec ou sans une culture de couverture de seigle, les parcelles recouvertes de seigle avaient des taux d'isolement moindres pour les champignons totaux en 1992 que les parcelles sans seigle, mais aucune différence n'a été observée en 1993. De plus, plusieurs espèces de Fusarium ont été isolées plus fréquemment des écales provenant de parcelles en rotation avec le seigle. Le flutolanil a diminué significativement les taux d'isolement de plusieurs champignons, incluant le R. solani AG-4, dans un des essais en 1992. L'ensemble des champignons isolés (en combinant tous les isolats de champignon) sur les parcelles traitées au flutolanil étaient plus élevés en 1993, mais pas en 1992 sur un des sites. Les taux d'isolement pour les différents genres et espèces de champignon différaient sur les deux milieux utilisés (agar à l'extrait de malt et agar au sel de malt). En particulier, l’AIternaria alternata et des espèces de Fusarium ont été isolés plus fréquemment sur l'agar au sel de malt, tandis que L theobromae, R. solani AG-4 et Trichoderma spp. Étaient plus souvent rencontrés sur l'agar à l'extrait de malt.Soilborne pathogens of peanut (Arachis hypogaea) often survive or over winter on peanut shells left on or in the soil. The effects of different crop rotations on the peanut shell mycobiota were compared in three field trials in 1992 and repeated in 1993. In two of the trials, plots grown continuously to peanut were either treated with the fungicide flutolanil or left untreated. Rotation practices varied with location and the crops in rotation with peanut were cotton (Gossypium hirsutum), rye (Secale cereale), bahiagrass (Paspalum notatum), and corn (Zea mays). In total, 31 different gene of fungi were isolated from shells. Over two-thirds of the isolates were Deuteromycotina, followed in frequency by Basidiomycetes, Ascomycetes, and Phycomycetes. The rotation practices affected the incidence of several pathogenic fungi (e.g., Fusarium spp., and Lasiodiplodia theobromae) in the peanut shells, but the results were not consistent across trials or years. Bahiagrass or corn grown in rotation with peanut reduced the frequency of Rhizoctonia solani AG-4 in shells. Rhizoctonia solani AG-2-2 and Macrophomina phaseolina were isolated at a greater level in the bahiagrass-peanut rotation. Where peanut was rotated with cotton with or without a winter cover crop of rye, plots containing rye had lower isolation rates for total fungi in 1992 than those without rye, but there was no différence in 1993. Also, several species of Fusarium were isolated more frequently from shells from plots rotated with rye. Flutolanil significantly lowered isolation rates of several fungi, including R. solani AG-4, in one trial in 1992. Total fungi isolated (all fungal isolates combined) in the flutolanil-treated plots were greater in 1993, but not in 1992 at one site. Isolation rates for the different gene and species of fungi differed on the two media utilized (malt-extract agar and malt-salt agar). In particular, Alternaria alternata and species of Fusarium were isolated more frequently on malt-salt agar, whereas L theobromae, R. solani AG-4 and Trichoderma spp. were more common on malt-extract agar

Grid-Enabled Non-Invasive Blood Glucose Measurement

Abstract. Earth and life sciences are at the forefront to successfully include computational simulations and modeling. Medical applications are often mentioned as the killer applications for the Grid. The complex methodology and models of Traditional Chinese Medicine offer different approaches to diagnose and treat a persons health condition than typical Western medicine. A possibility to make this often hidden knowledge ex-plicit and available to a broader audience will result in mutual synergies for Western and Chinese medicine as well as improved patient care. This paper proposes the design and implementation of a method to accurately estimate blood glucose values using a novel non-invasive method based on electro-transformation measures in human body meridians. The frame-work used for this scientific computing collaboration, namely the China-Austria Data Grid (CADGrid) framework, provides an Intelligence Base offering commonly used models and algorithms as Web/Grid-Services. The controlled execution of the Non-Invasive Blood Glucose Measure-ment Service and the management of scientific data that arise from model execution can be seen as the first application on top of the CADGrid

Quantum Entanglement of Excitons in Coupled Quantum Dots

Optically-controlled exciton dynamics in coupled quantum dots is studied. We show that the maximally entangled Bell states and Greenberger-Horne-Zeilinger (GHZ) states can be robustly generated by manipulating the system parameters to be at the avoided crossings in the eigenenergy spectrum. The analysis of population transfer is systematically carried out using a dressed-state picture. In addition to the quantum dot configuration that have been discussed by Quiroga and Johnson [Phys. Rev. Lett. \QTR{bf}{83}, 2270 (1999)], we show that the GHZ states also may be produced in a ray of three quantum dots with a shorter generation time.Comment: 16 pages, 7 figures, to appear in Phys. Rev.

Nucleosome Turnover Regulates Histone Methylation Patterns over the Genome

Recent studies have indicated that nucleosome turnover is rapid, occurring several times per cell cycle. To access the effect of nucleosome turnover on the epigenetic landscape, we investigated H3K79 methylation, which is produced by a single methyltransferase (Dot1l) with no known demethylase. Using chemical-induced proximity (CIP), we find that the valency of H3K79 methylation (mono-, di-, and tri-) is determined by nucleosome turnover rates. Furthermore, propagation of this mark is predicted by nucleosome turnover simulations over the genome and accounts for the asymmetric distribution of H3K79me toward the transcriptional unit. More broadly, a meta-analysis of other conserved histone modifications demonstrates that nucleosome turnover models predict both valency and chromosomal propagation of methylation marks. Based on data from worms, flies, and mice, we propose that the turnover of modified nucleosomes is a general means of propagation of epigenetic marks and a determinant of methylation valence. © 2018Previous work has revealed that “writers” and “erasers” of histone modifications play a critical role in regulating gene expression. Now, studies by Chory et al. reveal that, in addition, the patterns, kinetics, and topology of histone modifications over the genome can be shaped by the rate of nucleosome turnover

Dynamics and memory of heterochromatin in living cells

Posttranslational histone modifications are important for gene regulation, yet the mode of propagation and the contribution to heritable gene expression states remains controversial. To address these questions, we developed a chromatin in vivo assay (CiA) system employing chemically induced proximity to initiate and terminate chromatin modifications in living cells. We selectively recruited HP1α to induce H3K9me3-dependent gene silencing and describe the kinetics and extent of chromatin modifications at the Oct4 locus in fibroblasts and pluripotent cells. H3K9me3 propagated symmetrically and continuously at average rates of ∼0.18 nucleosomes/hr to produce domains of up to 10 kb. After removal of the HP1α stimulus, heterochromatic domains were heritably transmitted, undiminished through multiple cell generations. Our data enabled quantitative modeling of reaction kinetics, which revealed that dynamic competition between histone marking and turnover, determines the boundaries and stability of H3K9me3 domains. This framework predicts the steady-state dynamics and spatial features of the majority of euchromatic H3K9me3 domains over the genome

Generation of entangled states of two atoms inside a leaky cavity

An in-depth theoretical study is carried out to examine the quasi-deterministic entanglement of two atoms inside a leaky cavity. Two $\Lambda$-type three-level atoms, initially in their ground states, may become maximally entangled through the interaction with a single photon. By working out an exact analytic solution, we show that the probability of success depends crucially on the spectral function of the injected photon. With a cavity photon, one can generate a maximally entangled state with a certain probability that is always less than 50%. However, for an injected photon with a narrower spectral width, this probability can be significantly increased. In particular, we discover situations in which entanglement can be achieved in a single trial with an almost unit probability

Primakoff effect in eta-photoproduction off protons

We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.Comment: 5 pages, 6 figures, gamma-gamma*-eta form factor included, version to appear in Eur. Phys. J. A