1,856 research outputs found

    A fluctuation theory for Markov chains

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    A fluctuation theory for Markov chains on an ordered countable state space is developed, using ladder processes. These are shown to be Markov renewal processes. Results are given for the joint distribution of the extremum (maximum or minimum) and the first time the extremum is achieved. Also a new classification of the states of a Markov chain is suggested. Two examples are given

    A Comparative Study Between Alcoholics of Koraga Community, Alcoholics of General Population and Healthy Controls for Antioxidant Markers and Liver Function Parameters

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    Objectives: It is well established that long-term alcohol consumption leads to liver cirrhosis and other related disorders. Sufficient work has been done on biochemical markers of liver damage and antioxidant status of chronic alcoholics in general population. In the current study chronic alcoholics from a community called Koraga are analysed for the same parameters in a view to assess the extent of liver damage as compared to healthy controls and other alcoholics. Methods: Serum and urine samples from Koraga alcoholics (n=28), general alcoholics (n=30) and healthy controls (n=31) were analysed for liver function parameters and antioxidant markers. Liver function parameters were determined by automated analyzer. Markers of antioxidant status were estimated spectrophotometrically. The data was analysed using SPSS version 16.0. Results: There was significant increase in serum AST, serum ALT, serum GST and urine GST in both general and Koraga alcoholics when compared to healthy controls (p<0.0001). Serum ALT, serum GST and urine GST activity was significantly higher in general alcoholics when compared to Koraga alcoholics (p<0.001). Serum and urine total thiol levels were significantly lower in general alcoholics when compared to healthy controls and Koraga alcoholics (p<0.0001). We have observed no difference in total thiols level between healthy controls and Koraga alcoholics, in fact, there was significant increase in urine total thiols level in Koraga alcoholics compared to healthy controls (p<0.001). On Pearson’s correlation serum AST, serum ALT correlated positively with serum and urine GST (p<0.0001) and negatively with serum total thiols (p<0.0001). Serum GST correlated negatively with serum total thiols (p<0.0001). Conclusion: Results of our study possibly indicate that the extent of alcohol induced liver damage in Koraga subjects is comparatively lower than general alcoholics, even though the alcohol consumption is found to be higher in them. There may be some mechanism that is rendering them resistant to alcoholic liver damage which needs to be explored through further studies at molecular level

    The statistics of particle velocities in dense granular flows

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    We present measurements of the particle velocity distribution in the flow of granular material through vertical channels. Our study is confined to dense, slow flows where the material shears like a fluid only in thin layers adjacent to the walls, while a large core moves without continuous deformation, like a solid. We find the velocity distribution to be non-Gaussian, anisotropic, and to follow a power law at large velocities. Remarkably, the distribution is identical in the fluid-like and solid-like regions. The velocity variance is maximum at the core, defying predictions of hydrodynamic theories. We show evidence of spatially correlated motion, and propose a mechanism for the generation of fluctuational motion in the absence of shear.Comment: Submitted to Phys. Rev. Let

    (2E)-1-(5-Chloro­thio­phen-2-yl)-3-(2,4,5-trimeth­oxy­phen­yl)prop-2-en-1-one

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    In the title mol­ecule, C16H15ClO4S, the chloro­thio­phene and trimeth­oxy­phenyl rings make a dihedral angle of 31.12 (5)°. The C=C double bond exhibits an E conformation. In the crystal, C—H⋯O inter­actions generate bifurcated bonds, linking the mol­ecules into chains along the b axis

    Cuticular Biochemistry: Lambda-Cyhalothrin Induced Alterations in Mutant Drosophila Melanogaster

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    Derivatives of natural pyrethrum, synthetic pyrethroids, are well-established neurotoxins. However, they do interfere with the functioning of metabolic processes; the most important of these is chitin metabolism, a key process in the development of insects. Type II synthetic pyrethroid, lambda-cyhalothrin, when orally fed to Drosophila melanogaster revealed its efficacy in chitin synthesis modulation. Total proteins, glucosamine, N-acetylglucosamine, chitinase activity and chitin content exhibit significant changes in the final developmental stage, the adults. A reduction in chitin synthesis is suggestive of interference in polymerization process which is a must for cuticle formation. Involvement of lambda-cyhalothrin in chitin synthesis has been sought to be an additional mode of action, other than its neurotoxic nature

    SN 1993J VLBI (IV): A Geometric Determination of the Distance to M81 with the Expanding Shock Front Method

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    We compare the angular expansion velocities, determined with VLBI, with the linear expansion velocities measured from optical spectra for supernova 1993J in the galaxy M81, over the period from 7 d to ~9 yr after shock breakout. We estimate the distance to SN 1993J using the Expanding Shock Front Method (ESM). We find the best distance estimate is obtained by fitting the angular velocity of a point halfway between the contact surface and outer shock front to the maximum observed hydrogen gas velocity. We obtain a direct, geometric, distance estimate for M81 of D=3.96+-0.05+-0.29 Mpc with statistical and systematic error contributions, respectively, corresponding to a total standard error of $+-0.29 Mpc. The upper limit of 4.25 Mpc corresponds to the hydrogen gas with the highest observed velocity reaching no farther out than the contact surface a few days after shock breakout. The lower limit of 3.67 Mpc corresponds to this hydrogen gas reaching as far out as the forward shock for the whole period, which would mean that Rayleigh-Taylor fingers have grown to the forward shock already a few days after shock breakout. Our distance estimate is 9+-13 % larger than that of 3.63+-0.34 Mpc from the HST Key Project, which is near our lower limit but within the errors.Comment: 25 pages, 11 figures, accepted for publication in Ap

    (2E)-1-(5-Chloro­thio­phen-2-yl)-3-(2,3-dimeth­oxy­phen­yl)prop-2-en-1-one

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    In the title compound, C15H13ClO3S, the chloro­thio­phene and dimeth­oxy­phenyl groups are linked by a prop-2-en-1-one group. The C=C double bond exhibits an E conformation. The mol­ecule is non-planar, with a dihedral angle of 31.12 (5)° between the chloro­thio­phene and dimeth­oxy­phenyl rings. The meth­oxy group at position 3 is coplanar with the benzene ring to which it is attached, with a C—O—C—C torsion angle of −3.8 (3)°. The meth­oxy group attached at position 2 of the benzene ring is in a (+)synclinal conformation, as indicated by the C—O—C—C torsion angle of −73.6 (2)°. In the crystal, two different C—H⋯O inter­molecular inter­actions generate chains of mol­ecules extending along the b axis

    Genuine Counterfactual Communication with a Nanophotonic Processor

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    In standard communication information is carried by particles or waves. Counterintuitively, in counterfactual communication particles and information can travel in opposite directions. The quantum Zeno effect allows Bob to transmit a message to Alice by encoding information in particles he never interacts with. The first suggested protocol not only required thousands of ideal optical components, but also resulted in a so-called "weak trace" of the particles having travelled from Bob to Alice, calling the scalability and counterfactuality of previous proposals and experiments into question. Here we overcome these challenges, implementing a new protocol in a programmable nanophotonic processor, based on reconfigurable silicon-on-insulator waveguides that operate at telecom wavelengths. This, together with our telecom single-photon source and highly-efficient superconducting nanowire single-photon detectors, provides a versatile and stable platform for a high-fidelity implementation of genuinely trace-free counterfactual communication, allowing us to actively tune the number of steps in the Zeno measurement, and achieve a bit error probability below 1%, with neither post-selection nor a weak trace. Our demonstration shows how our programmable nanophotonic processor could be applied to more complex counterfactual tasks and quantum information protocols.Comment: 6 pages, 4 figure

    Assessment of marker-trait associations for drought and heat tolerance in bread wheat

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    Abiotic stresses are major constraints to wheat productivity in many parts of the world. Tolerance to abiotic stresses can be achieved indirectly by selection for morpho-physiological traits. Physiological trait based breeding has been associated with improved performance under stress; and hence can combat and adapt wheat to drought and heat stress. Therefore, in the present study, phenotyping was carried out for agro-physiological traits in 52 diverse wheat germplasm lines under timely sown, rainfed and late sown environments for two years. Mean yield of the genotypes over the six environments were positively correlated with NDVI, days to maturity and negatively correlated with canopy temperature. The phenotypic data validated marker-trait associations of a number of meta-QTLs identified earlier for different physiological and agronomic traits. Six and seven meta-QTL genomic regions were found to be consistent in their expression for two years under rainfed/restricted irrigation and late sown environments, respectively. Expression analysis of the underlying candidate gene AK248593.1 in meta-QTL26 region revealed two folds higher expression in the NILs carrying the co-localized SSR markers. The linked markers of the thirteen meta-QTL regions associated with different traits can be used for effective transfer of the QTLs through marker assisted selection in wheat breeding programmes
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