921 research outputs found

    A Field-Theoretic Approach to Connes' Gauge Theory on M4×Z2M_4\times Z_2

    Full text link
    Connes' gauge theory on M4×Z2M_4\times Z_2 is reformulated in the Lagrangian level. It is pointed out that the field strength in Connes' gauge theory is not unique. We explicitly construct a field strength different from Connes' one and prove that our definition leads to the generation-number independent Higgs potential. It is also shown that the nonuniqueness is related to the assumption that two different extensions of the differential geometry are possible when the extra one-form basis χ\chi is introduced to define the differential geometry on M4×Z2M_4\times Z_2. Our reformulation is applied to the standard model based on Connes' color-flavor algebra. A connection between the unimodularity condition and the electric charge quantization is then discussed in the presence or absence of νR\nu_R.Comment: LaTeX file, 16 page

    Occurrence and composition of manganese oxide minerals from the Nauta manganese deposit, Western Ghana

    Get PDF
    X-ray diffraction, ore microscopy, and electron microprobe studies have been done on ore samples obtained from the mine site at Nsuta, Ghana. Manganese ore minerals identified include nsutite, cryptomelane, pyrolusite, and lithiophorite. Except for pyrolusite, all these minerals are poorly crystalline. Chemical compositions of the minerals indicate little contamination by other elements. Quartz, muscovite, and clay minerals feature prominently as gangue in most samples. Textures are varied, and modes of occurrence are prinicipally by replacements, cavity or fracture fills, leaching and precipitaion. Mineral associations seem rather complex, as a result of which definitive paragenetic relations could not be established. Supergene formation of the manganese oxide ore is shown by the abundance of manganese minerals in solution channels such as fractures and cavities within silicate gangue. Much of the ore, howver, appears to have been enriched by leaching of gangue minerals and the later addution of manganese

    The role of traditional institutions in implementing the empowerment policy of Oetulu village, Musi district, Timor Tengah Utara regency

    Get PDF
    Purpose: This study aimed to determine the role of indigenous institutions in implementing the Oetulu village Empowerment Policy of Musi district of North Central Timor regency. Research methodology: The research method in this study was a descriptive research method with a qualitative approach. This study used policy implementation theory models from Donald Van Meter and Carl E. Van Horn (1975)). Results: Six variables affect the implementation, namely: First, policy standards in the form of rules related to indigenous institutions in Oetulu village have been flawed at the formulation stage. Second, the human resources of Oetulu village indigenous institutions are not utilized by the Village Government. Third, communication between organizations and strengthening activities is still not effective. Fourth, the implementing agent has an open level of communication both vertically and horizontally, but this communication is constrained at the vertical level. Fifth, economic conditions in the jurisdiction or implementing organization are not enough to support the implementation of the policy and. Sixth, the disposition of the implementer. Limitations: This research only discusses the role of indigenous institutions in implementing the community empowerment policy of Oetulu village, Musi district of North Central Timor regency. Contribution: This research becomes scientific information for public administration science

    Investigation of Superconducting Gap Structure in HfIrSi using muon spin relaxation/rotation

    Get PDF
    Appearance of strong spin-orbit coupling (SOC) is apparent in ternary equiatomic compounds with 5dd-electrons due to the large atomic radii of transition metals. SOC plays a significant role in the emergence of unconventional superconductivity. Here we examined the superconducting state of HfIrSi using magnetization, specific heat, zero and transverse-field (ZF/TF) muon spin relaxation/rotation (μ\muSR) measurements. Superconductivity is observed at TCT_\mathrm{C} = 3.6 K as revealed by specific heat and magnetization measurements. From the TFμ-\muSR analysis it is clear that superfluid density well described by an isotropic BCS type ss-wave gap structure. Furthermore, from TFμ-\muSR data we have also estimated the superconducting carrier density nsn_\mathrm{s} = 6.6 ×\times1026^{26}m3^{-3}, London penetration depth λL(0)\lambda_{L}(0) = 259.59 nm and effective mass mm^{*} = 1.57 mem_{e}. Our zero-field muon spin relaxation data indicate no clear sign of spontaneous internal field below TCT_\mathrm{C}, which implies that the time-reversal symmetry is preserved in HfIrSi. Theoretical investigation suggests Hf and Ir atoms hybridize strongly along the cc-axis of the lattice, which is responsible for the strong three-dimensionality of this system which screens the Coulomb interaction. As a result despite the presence of correlated dd-electrons in this system, the correlation effect is weakened, promoting electron-phonon coupling to gain importance.Comment: 8 pages, 4 figure

    Probing the superconducting ground state of ZrIrSi: A μ\muSR study

    Get PDF
    The superconducting ground state of newly reported ZrIrSi is probed by means of μ\muSR technique along with resistivity measurement. The occurrence of superconductivity at TCT_\mathrm{C} = 1.7 K is confirmed by resistivity measurement. ZF-μ\muSR study revealed that below TCT_\mathrm{C}, there is no spontaneous magnetic field in the superconducting state, indicates TRS is preserved in case of ZrIrSi. From TF-μ\muSR measurement, we have estimated the superfluid density as a function of temperature, which is described by an isotropic ss-wave model with a superconducting gap 2Δ(0)/kBTC2\Delta(0)/k_\mathrm{B}T_\mathrm{C} = 5.1, indicates the presence of strong spin-orbit coupling. {\it Ab-initio} electronic structure calculation indicates that there are four bands passing through the Fermi level, forming four Fermi surface pockets. We find that the low-energy bands are dominated by the 4d4d-orbitals of transition metal Zr, with substantially lesser weight from the 5d5d-orbitals of the Ir-atoms.Comment: 6 pages, 4 figure

    KEMAMPUAN PEMAHAMAN KONSEP MATEMATIS SISWA PADA PEMBELAJARAN MODEL RME

    Get PDF
    This research aimed to produce a study of students' mathematical concept understanding abilities in classes with Realistic Mathematics Education (RME) model learning and classes that did not receive RME model learning. This research was a quantitative method of quasi experiment model designed in the form of non-equivalent control group design involving two research classes determined using purposive sampling technique. The instrument used was a test of students' mathematical concept understanding ability in the form of description questions. The data analysis technique in this study used an independent sample t-test and N-gain score. The results of the analysis showed that students' mathematical concept understanding ability in the class that received RME model learning was better than that of those who did not receive RME model learning. The increase in students' mathematical concept understanding ability in the class with RME model learning was in a low category with an average gain score of 0.025. The low increase is due to the limited learning time at school during the adaptation period of new habits, so that learning with the RME model does not run effectively

    TINGKAH LAKU IKAN CUPANG (Betta splendes) TERHADAP PAKAN YANG BERBEDA

    Get PDF
    Ikan cupang (Betta splendes) adalah salah satu ikan hias air tawar di daerah tropis (Linke, 1994). Salah satu keistimewaan ikan cupang adalah daya tarik pada warna yang dimunculkan dari tubuhnya seperti bentuk, tampilan dan warnanya (Susanto, 1992). Fungsi utama pakan adalah untuk kelangsunan hidup dan pertumbuhan (Mujiman, 1992). Tingkah laku ikan terhadap pakan secara umum mempunyai dua pola yaitu aktif mencari pakan pada siang hari (diurnal) dan malam hari (nokturnal). Untuk ikan cupang termasuk tipe diurnal (Mudjiman, 2008). Penelitian ini bertujuan untuk mengetahui tingkah laku atau respon ikan cupang (Betta splendes) terhadap pakan yang berbeda dan untuk mengetahui pertumbuhan dan sintasan hidup ikan cupang (Betta splendes). Wadah yang digunakan dalam penelitian adalah toples kaca sebanyak 9 buah. Ikana cupang yang menjadi obyek penelitian sebanyak 9 ekor. Pakan yang diberikan adalah pakan cacing sutra (Tubifex sp), cacing darah, dan pelet “Takari” sebanyak 2 (dua) kali dalam sehari secara “ed libitum”. Respon makan ikan cupang berbeda-beda, dimana pemberian cacing sutra adalah kurangaktif, pakan cacing darah adalah sangat aktif dan pakan Takari adalah aktif. Pertumbuhan panjang rata-rata ikan cupang yang tertinggi pada wadah B (cacing darah) yaitu 3,3 cm dan diikuti wadah C (pakan Takari) yaitu 3,0 cm dan wadah A (cacing sutra) yaitu 2,9 cm. Pertambahan berat rata-rata yang tertinggi pada wadah B (cacing darah) yaitu 1,50gr, sedangkan wadah C (pakan Takari) yaitu 1,20 gr dan wadah A (cacing sutra) yaitu 1,07gr. Tingkat keberhasilan hidup ikan cupang (B.splendes) untuk semua wadah pemeliharaan adalah 100%

    Field Theory in Noncommutative Minkowski Superspace

    Full text link
    There is much discussion of scenarios where the space-time coordinates x^\mu are noncommutative. The discussion has been extended to include nontrivial anticommutation relations among spinor coordinates in superspace. A number of authors have studied field theoretical consequences of the deformation of N=1 superspace arising from nonanticommutativity of coordinates \theta, while leaving \bar{theta}'s anticommuting. This is possible in Euclidean superspace only. In this note we present a way to extend the discussion by making both \theta and \bar{theta} coordinates non-anticommuting in Minkowski superspace. We present a consistent algebra for the supercoordinates, find a star-product, and give the Wess-Zumino Lagrangian L_{WZ} within our model. It has two extra terms due to non(anti)commutativity. The Lagrangian in Minkowski superspace is always manifestly Hermitian and for L_{WZ} it preserves Lorentz invariance.Comment: 8 pages, added references, two-column format, published in PR
    corecore