Characterization of activated sludge abnormalities by image analysis and chemometric techniques

This work focuses on the use of chemometric techniques for identifying activated sludge process abnormalities. Chemometric methods combined with image analysis can improve activated sludge systems monitoring and minimize the need of analytical measurements. For that purpose data was collected from aggregated and filamentous biomass, biomass composition on Gram-positive/Gram-negative bacteria and viable/damaged bacteria, and operational parameters. Principal component analysis (PCA) was subsequently applied to identify activated sludge abnormalities, allowing the identification of several disturbances, namely filamentous bulking, pinpoint flocs formation, and zoogleal bulking as well as normal conditions by grouping the collected samples in corresponding clusters.     

Biaxial phase and coexistence of the two uniaxial nematic phases in the system sodium dodecyl sulphate–decanol–D2O

The system sodium dodecyl sulphate (SDS)/decanol (DeOH)/water presents, with temperature increase, an unusual phase transition between a stable biaxial phase and a coexistence region of the two uniaxial nematic phases (discotic N_D + cylindrical N_C). This has been detected previously by several methods for a sample with water/SDS molar ratio M_w = 36. Here, this system is investigated changing the ratio M_w to 32, where previously the coexistence region was reported after a discotic N_D phase, without the biaxial phase. We report now the existence of a biaxial N_B in the temperature range of ~2°C, defining for both values of M_w and the phase sequence as N_B – (N_D + N_C) – N_C. The change in temperature is followed by conoscopic and orthoscopic optical techniques and also analysed through the curve obtained by the technique of digital image processing of the textures, which reveals a continuous transition N_D – N_B – (N_D + N_C). While the biaxial phase is stable for at least 10 hours, in a reproducible way, the coexistence region evolves with time, and drops of the discotic phase grow immersed in a N_C matrix. Results are explained in terms of recent theories dealing with stabilisation of mixtures of cylinders and discs.     

Search for dilepton resonances in pp collisions at √s=7 TeV with the ATLAS detector

This Letter reports on a search for narrow high-mass resonances decaying into dilepton final states. The data were recorded by the ATLAS experiment in pp collisions at √s=7 TeV at the Large Hadron Collider and correspond to a total integrated luminosity of 1.08 (1.21) fb(-1) in the e(+)e(-) (μ(+)μ(-)) channel. No statistically significant excess above the standard model expectation is observed and upper limits are set at the 95% C.L. on the cross section times branching fraction of Z' resonances and Randall-Sundrum gravitons decaying into dileptons as a function of the resonance mass. A lower mass limit of 1.83 TeV on the sequential standard model Z' boson is set. A Randall-Sundrum graviton with coupling k/M(Pl)=0.1 is excluded at 95% C.L. for masses below 1.63 TeV.     

Measurement of dijet azimuthal decorrelations in pp collisions at sqrt(s)=7 TeV

Azimuthal decorrelations between the two central jets with the largest transverse momenta are sensitive to the dynamics of events with multiple jets. We present a measurement of the normalized differential cross section based on the full data set (∫Ldt=36 pb(-1)) acquired by the ATLAS detector during the 2010 sqrt(s)=7 TeV proton-proton run of the LHC. The measured distributions include jets with transverse momenta up to 1.3 TeV, probing perturbative QCD in a high-energy regime.     

Search for the Higgs boson in the H→WW→lνjj decay channel in pp collisions at √s=7 TeV with the ATLAS detector

A search for a Higgs boson has been performed in the H→WW→?νjj channel in 1.04 fb(-1) of pp collision data at √s=7 TeV recorded with the ATLAS detector at the Large Hadron Collider. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 240 GeV相似文献   

Catalytic DNA-based fluorescence polarization chiral sensing platform for l-histidine detection at trace level

This paper reports a novel fluorescence polarization (FP) chiral sensor approach based on a catalytic DNA. This platform involves an enzyme module (E), which was able to trigger the l-histidine-dependent cleavage of an RNA phosphoester bond of a substrate domain (S), whereas it did not accept the d-enantiomer as cofactor. Two assay formats were proposed, based on bi- and unimolecular strategies. The bimolecular design was related to the use of separate E and fluorescently labelled S* sequences. The two oligonucleotide strands were pre-assembled via complementary regions at their extremities. As the result of the large molecular volume of the formed assembly, the S* probe displayed a high fluorescence anisotropy signal. Upon addition of the l-histidine, the DNAzyme cleaved the phosphoester bond of the S* component, leading to the loss of stem stability and the release of single-stranded products of lower size. This was accompanied by a significant decrease in the fluorescence anisotropy response. As a simpler alternative, the unimolecular design, where E and S sequences are linked together through a loop to form a single fluorescent probe E-S*, was also investigated. It was found that the unimolecular approach provided an improved FP response relative to the bimolecular one. Under optimized operating conditions, such a chiral sensing platform allowed the detection of as low as 0.05 % of the l-histidine enantiomer in a non-racemic mixture.     

Canonical transformations in a higher-derivative field theory

It has been suggested that the chiral symmetry can be implemented only in classical Lagrangians containing higher covariant derivatives of odd order. Contrary to this belief, it is shown that one can construct an exactly soluble two-dimensional higher-derivative fermionic quantum field theory containing only derivatives of even order whose classical Lagrangian exhibits chiralgauge invariance. The original field solution is expressed in terms of usual Dirac spinors through a canonical transformation, whose generating function allows the determination of the new Hamiltonian. It is emphasized that the original and transformed Hamiltonians are different because the mapping from the old to the new canonical variables depends explicitly on time. The violation of cluster decomposition is discussed and the general Wightman functions satisfying the positive-definiteness condition are obtained.     

Flexible cellulose derivative PDLC type cells

In this work we perform a study of 250 μm thick flexible electro-optical PDLC type cells made from a biocompatible cellulose derivative film and several conductive substrates. The deposition of an ITO layer by reactive thermal evaporation on a polymeric substrate was referred to in the literature very recently and this type of coated substrate was used in the present work. In order to consider the influence of the substrates on the electro-optical behaviour of the cells, five cells were made using different substrates (three flexible polymers and two glass for comparison). Three of the substrates were coated under the same conditions, and the other two were commercially available substrates.     

Aging mechanisms of oil-in-water emulsions based on a bioemulsifier produced by Yarrowia lipolytica

The aging mechanisms of oil-in-water emulsions prepared with Yansan, a bioemulsifier produced by a Brazilian wild strain of Yarrowia lipolytica, IMUFRJ 50682, in glucose-based fermentation medium, were studied and compared with those prepared with Gum Arabic. Oil-in-water emulsions obtained by combining three different organic phases, perfluoro-n-hexane, n-hexadecane and toluene, with two aqueous buffers of different pH, and two bioemulsifiers, were studied through the evolution of the mean droplet size. The emulsions were prepared by sonication and their droplet size distribution was followed for 60 days at 301 K using image analysis. The results indicate that the aging mechanisms of the studied emulsions depend mainly on the bioemulsifier and on the pH of the medium. It is shown that the emulsions containing Gum Arabic age by coalescence while Yansan-based emulsions change their aging mechanisms from coalescence at pH 3 to molecular diffusion at pH 7.