912 research outputs found

    Use of LANDSAT imagery for soil survey

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    The author has identified the following significant results. The MSS channels 6 and 7 were considered the best to study the relative tonality of different spectral responses of soils, while channels 5 and 7 were best for natural vegetation, drainage patterns, and land use. Frequency ratio was the recommended index for use when analyzing a drainage pattern quantitatively

    NMR Determination of an Incommensurate Helical Antiferromagnetic Structure in EuCo2As2

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    We report 153^{153}Eu, 75^{75}As and 59^{59}Co nuclear magnetic resonance (NMR) results on EuCo2_2As2_2 single crystal. Observations of 153^{153}Eu and 75^{75}As NMR spectra in zero magnetic field at 4.3 K below an antiferromagnetic (AFM) ordering temperature TNT_{\rm N} = 45 K and its external magnetic field dependence clearly evidence an incommensurate helical AFM structure in EuCo2_2As2_2. Furthermore, based on 59^{59}Co NMR data in both the paramagnetic and the incommensurate AFM states, we have determined the model-independent value of the AFM propagation vector k{\bf k} = (0, 0, 0.73 ±\pm 0.07)2π\pi/cc where cc is the cc lattice parameter. Thus the incommensurate helical AFM state was characterized by only NMR data with model-independent analyses, showing NMR to be a unique tool for determination of the spin structure in incommensurate helical AFMs.Comment: 6 pages, 4 figures, accepted for publication in Phys.Rev.

    The structure of the space of affine Kaehler curvature tensors as a complex module

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    We use results of Matzeu and Nikcevic to decompose the space of affine Kaehler curvature tensors as a direct sum of irreducible modules in the complex settin

    Pengaruh Iradiasi Ultraviolet Terhadap Multiplikasi Tunas Aksiler Dan Kadar Klorofil Anyelir (Dianthus Caryophyllus L.)

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    Ultraviolet (UV) is one of the lights spectrum that causes plant cell to damage. The use of ultraviolet irradiation in combination with tissue culture techniques has not been widely used in somaclonal variation method for carnation breeding, whereas the source of ultraviolet irradiation is more easily obtained compared to other sources of irradiation such as gamma rays, x-rays and neutron rays. The purpose of this study was to determine effect of ultraviolet irradiation on the multiplication of axillary shoot in carnation. Explants of internode stem of carnation were grown in multiplication medium Murashige Skoog (MS) consisted of 10-7 M NAA and 5.10-6 M BAP. After four times subculture, the culture bottles were exposed to ultraviolet light C with some variation of irradiation time in combination with storage in light or dark. The results showed that ultraviolet light can reduce the number of shoots formed, shoot length and chlorophyll content of carnation. Based on the results obtained, ultraviolet radiation affected the organs of plants that were formed, but did not cause meristem activity to a standstil

    Geometric realizations of generalized algebraic curvature operators

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    We study the 8 natural GL equivariant geometric realization questions for the space of generalized algebraic curvature tensors. All but one of them is solvable; a non-zero projectively flat Ricci antisymmetric generalized algebraic curvature is not geometrically realizable by a projectively flat Ricci antisymmetric torsion free connection

    NMR studies of the incommensurate helical antiferromagnet EuCo2P2 : determination of the antiferromagnetic propagation vector

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    Recently Ding et al. [Phys. Rev. B 95, 184404 (2017)] reported that their nuclear magnetic resonance (NMR) study on EuCo2_2As2_2 successfully characterized the antiferromagnetic (AFM) propagation vector of the incommensurate helix AFM state, showing that NMR is a unique tool for determination of the spin structures in incommensurate helical AFMs. Motivated by this work, we have carried out 153^{153}Eu, 31^{31}P and 59^{59}Co NMR measurements on the helical antiferromagnet EuCo2_2P2_2 with an AFM ordering temperature TNT_{\rm N} = 66.5 K. An incommensurate helical AFM structure was clearly confirmed by 153^{153}Eu and 31^{31}P NMR spectra on single crystalline EuCo2_2P2_2 in zero magnetic field at 1.6 K and its external magnetic field dependence. Furthermore, based on 59^{59}Co NMR data in both the paramagnetic and the incommensurate AFM states, we have determined the model-independent value of the AFM propagation vector k = (0, 0, 0.73 ±\pm 0.09)2π\pi/cc where cc is the cc-axis lattice parameter. The temperature dependence of k is also discussed.Comment: 8 pages, 10 figures, accepted for publication in Phys. Rev. B. arXiv admin note: substantial text overlap with arXiv:1704.0629

    Evaluasi Plasma Nutfah Padi Gogo Berdasarkan Karakter Kuantitatif Perakaran Tanaman

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    Produktivitas padi gogo umumnya lebih rendah dibanding dengan padi sawah disebabkan oleh sifat fisik dan terbatasnya air dalam tanah serta karakteristik perakaran tanaman. Varietas padi gogo yang adaptif pada lingkungan lahan marginal dapat diperoleh melalui pemuliaan tanaman. Tujuan penelitian ini adalah mengevaluasi sistem perakaran plasma nutfah padi gogo melalui kemampuan perakarannya menembus lapisan keras dan untuk mengukur perakaran yang diduga berkaitan dengan adaptabilitasnya terhadap lingkungan kekeringan dan kepadatan tanah. Penelitian dilakukan di rumah kaca BB Biogen Bogor pada bulan Juli–Agustus 2015. Benih plasma nutfah 100 aksesi (varietas lokal) yang berasal dari provinsi Sumatra Utara, Sumatra Selatan, Sulawesi Utara, Jambi, Kalimantan Tengah, Kalimantan Timur, NTT, Jawa Tengah, Jawa Timur, Jawa Barat, DIY, dan Banten ditanam pada pot dengan bagian dasar dilapisi dengan kombinasi campuran 60% parafin dan 40% vaselin yang setara dengan kekerasan 12 bar. Hasil penelitian menunjukkan pengelompokan plasma nutfah 100 varietas padi gogo dapat dikelompokkan berdasarkan varietas yang karakteristiknya jauh berbeda dengan yang lain, yaitu varietas Si Gambiri Etek asal Sumatra Utara, varietas Cikapundeng asal Banten, dan varietas Ketan Kasumba B asal Banten. Plasma nutfah yang memiliki karakteristik perakaran baik (bobot akar dan rasio akar tajuk yang tinggi) dapat digunakan sebagai tetua dalam program pemuliaan tanaman
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