1,553 research outputs found

    Production of Soybean Varieties Under Saturated Soil Culture on Tidal Swamps

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    Saturated soil culture (SSC) is a cultivation technology that gives continuous irrigation and maintains water depth constantly and makes soil layer in saturated condition. By keeping the water-table constantly, soybean will be avoided from negative effect of inundation on soybean growth because soybean will acclimatize and improve its growth. The objective of the research was to study the response of soybean varieties under saturated soil culture on tidal swamps. The research was conducted at Banyu Urip of Tanjung Lago Sub District, Banyuasin District, South Sumatera Province, Indonesia from April to August 2009. The experiment was arranged in a split plot design with three replications. The main plot was water depth in the furrow consisted of without watering, 10, 20, 30, 40 cm under soil surface (uss). The subplot was soybean variety consisted of Tanggamus, Slamet, Willis, and Anjasmoro. The result showed that the interaction between varieties and water depth significantly affected growth and seed production, except pod numbers/plant. The values of all variables were higher under SSC compared to those cultivated without watering (control), but varieties responded to SSC differently. The highest seed production was obtained from Tanggamus with 40 cm uss, i.e. 4.83 ton/ha but it was not significantly different from those at water depth 20 (4.63 ton/ha) and 30 cm uss (4.71 ton/ha). However, technically and economically, 20 cm uss was the most appropriate water depth for soybean production on tidal swamps

    Field-induced confinement in (TMTSF)2ClO4 under accurately aligned magnetic fields

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    We present transport measurements along the least conducting c direction of the organic superconductor (TMTSF)2ClO4, performed under an accurately aligned magnetic field in the low temperature regime. The experimental results reveal a two-dimensional confinement of the carriers in the (a,b) planes which is governed by the magnetic field component along the b' direction. This 2-D confinement is accompanied by a metal-insulator transition for the c axis resistivity. These data are supported by a quantum mechanical calculation of the transverse transport taking into account in self consistent treatment the effect of the field on the interplane Green function and on the intraplane scattering time

    Orbital quantization in the high magnetic field state of a charge-density-wave system

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    A superposition of the Pauli and orbital coupling of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wavevector. By contrast to the purely orbital field-induced density-wave effects which require a strongly imperfect nesting of the Fermi surface, the new transitions can occur even if the Fermi surface is well nested at zero field. We suggest that such transitions are observed in the organic metal α\alpha-(BEDT-TTF)2_2KHg(SCN)4_4 under a strongly tilted magnetic field.Comment: 14 pages including 4 figure

    Liquid Crystal-Solid Interface Structure at the Antiferroelectric-Ferroelectric Phase Transition

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    Total Internal Reflection (TIR) is used to probe the molecular organization at the surface of a tilted chiral smectic liquid crystal at temperatures in the vicinity of the bulk antiferroelectric-ferroelectric phase transition. Data are interpreted using an exact analytical solution of a real model for ferroelectric order at the surface. In the mixture T3, ferroelectric surface order is expelled with the bulk ferroelectric-antiferroelectric transition. The conditions for ferroelectric order at the surface of an antiferroelectric bulk are presented

    HST Observations of SGR 0526-66: New Constraints on Accretion and Magnetar Models

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    Soft Gamma-ray Repeaters (SGRs) are among the most enigmatic sources known today. Exhibiting huge X- and Gamma-ray bursts and flares, as well as soft quiescent X-ray emission, their energy source remains a mystery. Just as mysterious are the Anomalous X-ray pulsars (AXPs), which share many of the same characteristics. Thanks to recent Chandra observations, SGR 0526-66, the first SGR, now appears to be a transition object bridging the two classes, and therefore observations of it have implications for both SGRs and AXPs. The two most popular current models for their persistent emission are accretion of a fossil disk or decay of an enormous (~10^15 G) magnetic field in a magnetar. We show how deep optical observations of SGR 0526-66, the only SGR with small enough optical extinction for meaningful observations, show no evidence of an optical counterpart. These observation place strong new constraints on both accretion disk and magnetar models, and suggest that the spectral energy distribution may peak in the hard-UV. Almost all accretion disks are excluded by the optical data, and a magnetar would require a ~10^15-10^16 G field.Comment: 23 pages, 5 figures. Accepted by Ap

    Optimal topological simplification of discrete functions on surfaces

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    We solve the problem of minimizing the number of critical points among all functions on a surface within a prescribed distance {\delta} from a given input function. The result is achieved by establishing a connection between discrete Morse theory and persistent homology. Our method completely removes homological noise with persistence less than 2{\delta}, constructively proving the tightness of a lower bound on the number of critical points given by the stability theorem of persistent homology in dimension two for any input function. We also show that an optimal solution can be computed in linear time after persistence pairs have been computed.Comment: 27 pages, 8 figure

    Energy loss of fast quarks in nuclei

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    We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H^2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is dE/dz=2.32±0.52±0.5-dE/dz = 2.32 \pm 0.52\pm 0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in nuclear environment.Comment: 5 pages, including 4 figure
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