16,274 research outputs found

    Photonic crystal nanofiber using an external grating

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    We implement a photonic crystal nanofiber device by reversibly combining an optical nanofiber and a nanofabricated grating. Using the finite-difference time-domain method, we design the system for minimal optical loss while tailoring the resonant wavelength and bandwidth of the device. Experimentally we demonstrate that the combined system shows a strong photonic stop-band in good agreement with numerical predictions. The resulting device may be used to realize strong light-matter coupling near to the nanofiber surface

    Evolution of Primordial Black Holes in Loop Quantum Gravity

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    In this work, we study the evolution of Primordial Black Holes within the context of Loop Quantum Gravity. First we calculate the scale factor and energy density of the universe for different cosmic era and then taking these as inputs we study evolution of primordial black holes. From our estimation it is found that accretion of radiation does not affect evolution of primordial black holes in loop quantum gravity even though a larger number of primordial black holes may form in early universe in comparison with Einstein's or scalar-tensor theories.Comment: 8 pages, 1 figur

    In vitro mass multiplication of Jatropha (Jatropha curcas L.) through axillary bud culture

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    The present investigation was conducted for mass multiplication of Jatropha curcas L. through axillary bud culture. For this nodal segment from 3-5 months old nursery grown plants were used as explants for axillary bud culture. The sterilization treatment involving dipping explants in 0.1 per cent HgCl2 solution for 5 minutes resulted in minimum contamination and maximum establishment of nodal explants. The treatment MS medium supplemented with 1.0 mg/L BAP and 1.0 mg/L IAA was the best for culture establishment, shoot proliferation and multiplication of the axillary buds which exhibited highest value in each parameter like establishment (76.1%), number of days taken for shoot initiation (3.1 days), length of longest shoot (6.8 cm), number of leaves on main shoot (7.1) and number of shoots per explant (6.3). Among different treatments for root initiation, half MS media fortified with 1 mg/L IBA, 3 mg/ L NAA and 0.25 g AC gave best result in maximum number of rooting percentage (60) with minimum time taken for root initiation (13.3 days), produced maximum number of roots per shoots (5.1) and length of longest root (4.9 cm) when established shoots were treated with it. Such produced plantlets showed nearly cent per cent survival after hardening and acclimatization. It showed that explants surface sterilized with 0.1 per cent HgCl2 solution for 5 minutes inoculated in MS medium supplemented with 1.0 mg/L BAP and 1.0 mg/L IAA and half MS media fortified with 1 mg/L IBA, 3 mg/L NAA and 0.25 g AC were best in shoot establishment and root development respectively for mass multiplication of J. curcas L. through axillary bud culture

    Spam detection in collaborative tagging

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    The algorithm proposed will be able to identify the spammers and demote their ranks cocooning the users from their malicious intents and gives popular and relevant resources in a collaborative tagging system or in online dating sites, or any other online forum where there are discussions like quora, amazon feedbacks etc. by a suitable algorithm on lines of an existing one but with multifaceating dimensions as against them. We have taken the assumption that there are two factors on which the virtuosity of a user with reference to a resource or a document depends on. First and foremost an expert should have a rich content resource in his repertoire and his dexterity to find good resources, however the paraphernalia for rich resource is virtuosity of users who tagged it. Secondly, an expert should be first to identify intriguing or riveting documents

    Gyroscopic Precession and Inertial Forces in Axially Symmetric Stationary Spacetimes

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    We study the phenomenon of gyroscopic precession and the analogues of inertial forces within the framework of general relativity. Covariant connections between the two are established for circular orbits in stationary spacetimes with axial symmetry. Specializing to static spacetimes, we prove that gyroscopic precession and centrifugal force both reverse at the photon orbits. Simultaneous non-reversal of these in the case of stationary spacetimes is discussed. Further insight is gained in the case of static spacetime by considering the phenomena in a spacetime conformal to the original one. Gravi-electric and gravi-magnetic fields are studied and their relation to inertial forces is established.Comment: 21 pages, latex, no figures, http://202.41.67.76/~nayak/gpifass.te

    Lung Injury Pathways: Adenosine Receptor 2B Signaling Limits Development of Ischemic Bronchiolitis Obliterans Organizing Pneumonia

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    Purpose/Aim of the Study: Adenosine signaling was studied in bronchiolitis obliterans organizing pneumonia (BOOP) resulting from unilateral lung ischemia. Materials and Methods: Ischemia was achieved by either left main pulmonary artery or complete hilar ligation. Sprague–Dawley (SD) rats, Dahl salt sensitive (SS) rats and SS mutant rat strains containing a mutation in the A2B adenosine receptor gene (Adora2b) were studied. Adenosine concentrations were measured in bronchoalveolar lavage (BAL) by HPLC. A2A (A2AAR) and A2B adenosine receptor (A2BAR) mRNA and protein were quantified. Results: Twenty-four hours after unilateral PA ligation, BAL adenosine concentrations from ischemic lungs were increased relative to contralateral lungs in SD rats. A2BAR mRNA and protein concentrations were increased after PA ligation while miR27a, a negatively regulating microRNA, was decreased in ischemic lungs. A2AAR mRNA and protein concentrations remained unchanged following ischemia. A2BAR protein was increased in PA ligated lungs of SS rats after 7 days, and 4 h after complete hilar ligation in SD rats. SS-Adora2b mutants showed a greater extent of BOOP relative to SS rats, and greater inflammatory changes. Conclusion: Increased A2BAR and adenosine following unilateral lung ischemia as well as more BOOP in A2BAR mutant rats implicate a protective role for A2BAR signaling in countering ischemic lung injury

    Comparison of ocean color chlorophyll algorithms for IRS-P40CM sensor using in-situ data

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    In-situ chlorophyll concentration data and remote sensing reflectance (Rrs) measurements collected in -six different ship campaigns in the Arabian Sea were used to evaluate the accuracy, precision, and suitability of different ocean color chlorophyll algorithms for the Arabian Sea. The bio-optical data sets represent the typical range of biooptical conditions expected in this region and are composed of 47 stations encompassing chlorophyll concentration, between 0.072 and 5.90 mg m -3, with 43 observations in case I water and 4 observations in case I1 water. Six empirical chlorophyll algorithms [i.e. Aiken-C, POLDER-C, OCTS-C, Morel-3, Oceaa Chlorophyll-2 (OC2) and Ocean Chlorophyll-4 (OC4)] were selected for analysis on the Arabian Sea data set. Numerous statistical and graphical criterions were used to evaluate the performance of these algorithms. Among these six chlorophyll algorithms two chlorophyll algorithms (i.e. OC2 and OC4) performed well in the case I waters of the Arabian Sea. The OC2 algorithm, a modified cubic polynomial function which uses ratio of Rrs490 nm and Rrs555 nm (where, Rrs is remote sensing reflectance), performed well with r2=0.85; rms =0.15. The OC4 algorithm, a four-band (443, 490,510, 555 nm), maximum band ratio formulation was found best on the basis of statistical analysis results with r2=0.85 and rms=0.14. Both OC2 and OC4 algorithms failed to estimate chloróphyll in Trichodesmium dominated waters. The OC2 algorithm was preferred over OC4 algorithm for routine processing of the OCM data to generate chlorophyll-a images, as it uses a band ratio of 490/555 nm and atmospheric correction is more accurate in 490 nm compared to 443 nm band, which is used by OC4 algorithm
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