388 research outputs found

    Modeling charge transport in Swept Charge Devices for X-ray spectroscopy

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    We present the formulation of an analytical model which simulates charge transport in Swept Charge Devices (SCDs) to understand the nature of the spectral redistribution function (SRF). We attempt to construct the energy-dependent and position dependent SRF by modeling the photon interaction, charge cloud generation and various loss mechanisms viz., recombination, partial charge collection and split events. The model will help in optimizing event selection, maximize event recovery and improve spectral modeling for Chandrayaan-2 (slated for launch in 2014). A proto-type physical model is developed and the algorithm along with its results are discussed in this paper.Comment: 9 pages, 7 figures, Proc. SPIE 8453, High Energy, Optical, and Infrared Detectors for Astronomy

    Classics: Are we Utilizing our Water Resources Wisely?

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    Modern technology has been used in building high dams and storing water. But in the matter of conveying the precious water to the field and making it available for plant growth, technology has lagged behind. Accurate quantitative appraisal of resource availability, and its utilization is urgently needed. Water conservation measures have to be adopted taking lessons from Israel, a country which has made a success of its agriculture. Greater attention should be paid to groundwater. Porous and fractured rocks below ground function as a vast interconnected reservoir. This natural storage which nature has provided should be allowed to get recharged with rainwater. These measures can be best attempted through the organization of autonomous River Authorities for each major river basin and sub-basin

    Silicon-induced changes in antifungal phenolic acids, flavonoids, and key phenylpropanoid pathway genes during the interaction between miniature roses and the biotrophic pathogen <em>Podosphaera pannosa</em>

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    Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection

    A fiber optic biosensor for the detection of cholesterol levels based on chitosan coated long period grating.

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    A fiber optic sensor for the measurement of total cholesterol is designed and developed. The developed chitosan coated long period grating (LPG) sensor shows a sensitivity of 5.025×106 pm·mL/g in the measurement range of the sensor. The sensor also shows a linear response in the measured range of cholesterol levels, which is highly desirable for exploitation as a commercial cholesterol sensor

    A Profile of Bacteriologically Confirmed Pulmonary Tuberculosis in Children

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    Objective: To describe the clinical profile of children with bacteriologically confirmed tuberculosis. Study Design: A multicentric study was conducted in three hospitals in Chennai city between July 1995 and December 1997. Children aged 6 months to 12 years with signs and symptoms suggestive of tuberculosis were investigated further. Clinical examination, chest radiograph, tuberculin skin test with 1 TU PPD and, sputum or gastric lavage for mycobacterial smear and culture were done for all and, lymph node biopsy when necessary. Results: A total of 2652 children were registered and tuberculosis was bacteriologically confirmed in 201. Predominant symptoms were history of an insidious illness (49%), fever and cough (47%), loss of weight (41%) and a visible glandular swelling (49%). Respiratory signs were few and 62% were undernourished. Over half the patients with confirmed TB had normal chest X-ray. Abnormal X-ray findings included parenchymal opacities in 47% and hilar or mediastinal lymphadenopathy in 26%. The prevalence of isoniazid resistance was 12.6% and MDR TB 4%. Conclusions: Children with tuberculosis present with fever and cough of insidious onset. Lymphadenopathy is a common feature even in children with pulmonary TB. A significant proportion of children have normal chest X-rays despite positive gastric aspirate cultures. Drug resistance rates in children mirror the pattern seen in adults in this geographic area

    Generalized calculation of magnetic coupling constants for Mott-Hubbard insulators: Application to ferromagnetic Cr compounds

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    Using a Rayleigh-Schr\"odinger perturbation expansion of multi-band Hubbard models, we present analytic expressions for the super-exchange coupling constants between magnetic transition metal ions of arbitrary separation in Mott-Hubbard insulators. The only restrictions are i) all ligand ions are closed shell anions and ii) all contributing interaction paths are of equal length. For short paths, our results essentially confirm the Goodenough-Kanamori-Anderson rules, yet in general there does not exist any simple rule to predict the sign of the magnetic coupling constants. The most favorable situation for ferromagnetic coupling is found for ions with less than half filled d shells, the (relative) tendency to ferromagnetic coupling increases with increasing path length. As an application, the magnetic interactions of the Cr compounds Rb2_2CrCl4_4, CrCl3_3, CrBr3_3 and CrI3_3 are investigated, all of which except CrCl3_3 are ferromagnets.Comment: 13 pages, 6 eps figures, submitted to Phys Rev

    Classical R-Matrices and the Feigin-Odesskii Algebra via Hamiltonian and Poisson Reductions

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    We present a formula for a classical rr-matrix of an integrable system obtained by Hamiltonian reduction of some free field theories using pure gauge symmetries. The framework of the reduction is restricted only by the assumption that the respective gauge transformations are Lie group ones. Our formula is in terms of Dirac brackets, and some new observations on these brackets are made. We apply our method to derive a classical rr-matrix for the elliptic Calogero-Moser system with spin starting from the Higgs bundle over an elliptic curve with marked points. In the paper we also derive a classical Feigin-Odesskii algebra by a Poisson reduction of some modification of the Higgs bundle over an elliptic curve. This allows us to include integrable lattice models in a Hitchin type construction.Comment: 27 pages LaTe

    Effect of silver incorporation on the structural and morphological characteristics of RF sputtered indium oxide films.

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    Radio frequency (RF) magnetron sputtered silver incorporated indium oxide thin films were prepared and their structural and morphological properties were studied using micro- Raman spectroscopy, Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDS). Raman modes corresponding to the cubic bixbyite phase of indium oxide were obtained through micro-Raman spectroscopy. AFM images exhibited dense distribution of grains. Elemental analysis using EDS spectra confirmed the presence of indium, silver and oxygen in the prepared films

    Nontypeable haemophilus influenzae induces sustained lung oxidative stress and protease expression

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    © 2015 King et al. Nontypeable Haemophilus influenzae (NTHi) is a prevalent bacterium found in a variety of chronic respiratory diseases. The role of this bacterium in the pathogenesis of lung inflammation is not well defined. In this study we examined the effect of NTHi on two important lung inflammatory processes 1), oxidative stress and 2), protease expression. Bronchoalveolar macrophages were obtained from 121 human subjects, blood neutrophils from 15 subjects, and human-lung fibroblast and epithelial cell lines from 16 subjects. Cells were stimulated with NTHi to measure the effect on reactive oxygen species (ROS) production and extracellular trap formation. We also measured the production of the oxidant, 3-nitrotyrosine (3-NT) in the lungs of mice infected with this bacterium. NTHi induced widespread production of 3-NT in mouse lungs. This bacterium induced significantly increased ROS production in human fibroblasts, epithelial cells, macrophages and neutrophils; with the highest levels in the phagocytic cells. In human macrophages NTHi caused a sustained, extracellular production of ROS that increased over time. The production of ROS was associated with the formation of macrophage extracellular trap-like structures which co-expressed the protease metalloproteinase-12. The formation of the macrophage extracellular trap-like structures was markedly inhibited by the addition of DNase. In this study we have demonstrated that NTHi induces lung oxidative stress with macrophage extracellular trap formation and associated protease expression. DNase inhibited the formation of extracellular traps

    Fibre bundle formulation of nonrelativistic quantum mechanics: I. Introduction. The evolution transport

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    We propose a new systematic fibre bundle formulation of nonrelativistic quantum mechanics. The new form of the theory is equivalent to the usual one but it is in harmony with the modern trends in theoretical physics and potentially admits new generalizations in different directions. In it a pure state of some quantum system is described by a state section (along paths) of a (Hilbert) fibre bundle. Its evolution is determined through the bundle (analogue of the) Schr\"odinger equation. Now the dynamical variables and the density operator are described via bundle morphisms (along paths). The mentioned quantities are connected by a number of relations derived in this work. The present first part of this investigation is devoted to the introduction of basic concepts on which the fibre bundle approach to quantum mechanics rests. We show that the evolution of pure quantum-mechanical states can be described as a suitable linear transport along paths, called evolution transport, of the state sections in the Hilbert fibre bundle of states of a considered quantum system.Comment: 26 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and amsfonts are required. Revised: new material, references, and comments are added. Minor style chages. Continuation of quan-ph/9803083. For continuation of the this series see http://www.inrne.bas.bg/mathmod/bozhome
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