3,060 research outputs found

    Trench width dependant deeply etched surface-defined InP gratings for low-cost high speed DFB/DBR

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    In this paper we are reporting a fabrication process for multi-section telecom lasers based on surface defined lateral gratings, which is compatible with low-cost high-throughput nano-imprint lithography. A new grating definition process is developed, which allow a better control of the cross section geometry to obtain higher coupling strength

    Exposure to NO2 in occupational built environments in urban centre in Lahore

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    Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres

    Eco-biology of Mastacembelus pancalus (Ham.) and their distribution in different water bodies

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    The eco-biological of the spiny eel, Mastacembelus pailcalus in the river Padma, adjacent flood plains and ponds were influenced by various physico-chemical factors such as water temperature, water transparency, pH, dissolved oxygen, free carbon dioxide and alkalinity. Flood plain areas are the best habitat for the M. pancalus with maximum abundance

    Exposure to NO<inf>2</inf> in occupationalbuilt environmnets in urban centre in Lahore

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    Increased economic growth, urbanisation and substantial rise in automobile vehicles has contributed towards the elevated levels of air pollution in major cities in Pakistan. Aone week study was conducted by using passive samplers to assess NO2 concentration in occupational built environments at two most congested and populated sites of Lahore. Both sites were locatedon the busy roads of Lahore. At Site-I the highest concentration was in outdoors followed by corridor and indoor. While at Site II all the sampling location wereindoors and level were comparable to that of outdoor levelsat Site I. The results suggest the likely contribution of ambient sources in exposure to indoor NO2 in educational and other occupational built environments in urban centres

    The {\eta}'-carbon potential at low meson momenta

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    The production of η\eta^\prime mesons in coincidence with forward-going protons has been studied in photon-induced reactions on 12^{12}C and on a liquid hydrogen (LH2_2) target for incoming photon energies of 1.3-2.6 GeV at the electron accelerator ELSA. The η\eta^\prime mesons have been identified via the ηπ0π0η6γ\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6 \gamma decay registered with the CBELSA/TAPS detector system. Coincident protons have been identified in the MiniTAPS BaF2_2 array at polar angles of 2θp112^{\circ} \le \theta _{p} \le 11^{\circ}. Under these kinematic constraints the η\eta^\prime mesons are produced with relatively low kinetic energy (\approx 150 MeV) since the coincident protons take over most of the momentum of the incident-photon beam. For the C-target this allows the determination of the real part of the η\eta^\prime-carbon potential at low meson momenta by comparing with collision model calculations of the η\eta^\prime kinetic energy distribution and excitation function. Fitting the latter data for η\eta^\prime mesons going backwards in the center-of-mass system yields a potential depth of V = -(44 ±\pm 16(stat)±\pm15(syst)) MeV, consistent with earlier determinations of the potential depth in inclusive measurements for average η\eta^\prime momenta of \approx 1.1 GeV/cc. Within the experimental uncertainties, there is no indication of a momentum dependence of the η\eta^\prime-carbon potential. The LH2_2 data, taken as a reference to check the data analysis and the model calculations, provide differential and integral cross sections in good agreement with previous results for η\eta^\prime photoproduction off the free proton.Comment: 9 pages, 13 figures. arXiv admin note: text overlap with arXiv:1608.0607

    Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: Bangladesh

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    Irrigated farming / Poverty / Irrigation management / Water resource management / Policy / Planning / Institutions / Organizations / Local government / Non-governmental organizations / Legislation / Water users / Participatory management / Public sector / Water allocation / Cost recovery / Households / Income / Expenditure / Irrigation canals / Bangladesh

    Photoproduction of eta mesons from the neutron: cross sections and double polarization observable E

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    Photoproduction of η\eta mesons from neutrons} \abstract{Results from measurements of the photoproduction of η\eta mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the η3π06γ\eta\to3\pi^{0}\to6\gamma decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of γnnη\gamma n\rightarrow n\eta. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow P11P_{11} state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable EE. Both data sets together were also used to extract the helicity dependent cross sections σ1/2\sigma_{1/2} and σ3/2\sigma_{3/2}. The narrow structure in the excitation function of γnnη\gamma n\rightarrow n\eta appears associated with the helicity-1/2 component of the reaction

    Measurement of pi^0 photoproduction on the proton at MAMI C

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    Differential cross sections for the gamma p -> pi^0 p reaction have been measured with the A2 tagged-photon facilities at the Mainz Microtron, MAMI C, up to the center-of-mass energy W=1.9 GeV. The new results, obtained with a fine energy and angular binning, increase the existing quantity of pi^0 photoproduction data by ~47%. Owing to the unprecedented statistical accuracy and the full angular coverage, the results are sensitive to high partial-wave amplitudes. This is demonstrated by the decomposition of the differential cross sections in terms of Legendre polynomials and by further comparison to model predictions. A new solution of the SAID partial-wave analysis obtained after adding the new data into the fit is presented.Comment: 13 pages, 12 figures, 1 tabl
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