8,227 research outputs found

    Axiomatic Digital Topology

    Full text link
    The paper presents a new set of axioms of digital topology, which are easily understandable for application developers. They define a class of locally finite (LF) topological spaces. An important property of LF spaces satisfying the axioms is that the neighborhood relation is antisymmetric and transitive. Therefore any connected and non-trivial LF space is isomorphic to an abstract cell complex. The paper demonstrates that in an n-dimensional digital space only those of the (a, b)-adjacencies commonly used in computer imagery have analogs among the LF spaces, in which a and b are different and one of the adjacencies is the "maximal" one, corresponding to 3n\"i1 neighbors. Even these (a, b)-adjacencies have important limitations and drawbacks. The most important one is that they are applicable only to binary images. The way of easily using LF spaces in computer imagery on standard orthogonal grids containing only pixels or voxels and no cells of lower dimensions is suggested

    Supersymmetric Higgs Bosons and Beyond

    Full text link
    We consider supersymmetric models that include particles beyond the Minimal Supersymmetric Standard Model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest CP-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the Standard Model and the MSSM.Comment: References added. Mistake in Eq. 14 corrected, conclusions unchanged. Typos corrected. Version accepted for publication in PRD. 50 pages, 29 figure

    Radiative corrections to the Casimir force and effective field theories

    Get PDF
    Radiative corrections to the Casimir force between two parallel plates are considered in both scalar field theory of one massless and one massive field and in QED. Full calculations are contrasted with calculations based on employing ``boundary-free'' effective field theories. The difference between two previous results on QED radiative corrections to the Casimir force between two parallel plates is clarified and the low-energy effective field theory for the Casimir effect in QED is constructed.Comment: 17 pages, revte

    A protocol for Agrobacterium-mediated transformation of Kalanchoë blossfeldiana with a flavonoid 3',5' hydroxylase (F3'5'H) gene

    Get PDF
    In the present investigation, explants from Kalanchoë blossfeldiana were used for gene transformation. The young leaves were inoculated with Agrobacterium tumefaciens LBA4404 strain with a binary vector plasmid pArtblue containing F3'5'H gene under control of CaMV35S promoter and nptII selectable marker gene. After inoculation, the explants were transferred to the co-cultivation medium. They were then transferred to the selection medium containing kanamycin and were sub-cultured every two weeks. Leaves of the putative transgenic shoots that survived in the selection medium were used in reverse transcription polymerase chain reaction (RT-PCR) analysis to detect gene expression. The RT-PCR analysis showed the presence of 550 bp F3'5'H amplification products and had an expression of F3'5'H gene. Plants with the introduced F3'5'H gene produced totally pale red flowers.Key words: Kalanchoë blossfeldiana, Agrobacterium-mediated transformation, young leaf, F3'5'H gene, reverse transcription-polymerase chain reaction (RT-PCR)

    A second black hole candidate in a M31 globular cluster is identified with XMM-Newton

    Full text link
    We use arguments developed in previous work to identify a second black hole candidate associated with a M31 globular cluster, Bo 144, on the basis of X-ray spectral and timing properties. The 2002 XMM-Newton observation of the associated X-ray source (hereafter XBo 144) revealed behaviour that is common to all low-mass X-ray binaries (LMXBs) in the low-hard state. Studies have shown that neutron star LMXBs exhibit this behaviour at 0.01-1000 keV luminosities <=10% of the Eddington limit (L_Edd). However, the unabsorbed 0.3-10 keV XBo 144 luminosity was ~0.30 L_Edd for a 1.4 M_sun neutron star, and the expected 0.01-1000 keV luminosity is 3-7 times higher. We therefore identify XBo 144 as a black hole candidate. Furthermore, it is the second black hole candidate to be consistent with formation via tidal capture of a mean sequence donor in a GC; such systems were previously though non-existent, because the donor was thought to be disrupted during the capture process.Comment: Accepted for publication in MRAS letters. Four pages, three figure

    Neutrino-Deuteron Scattering in Effective Field Theory at Next-to-Next-to Leading Order

    Get PDF
    We study the four channels associated with neutrino-deuteron breakup reactions at next-to-next to leading order in effective field theory. We find that the total cross-section is indeed converging for neutrino energies up to 20 MeV, and thus our calculations can provide constraints on theoretical uncertainties for the Sudbury Neutrino Observatory. We stress the importance of a direct experimental measurement to high precision in at least one channel, in order to fix an axial two-body counterterm.Comment: 32 pages, 14 figures (eps

    Collision Dynamics and Solvation of Water Molecules in a Liquid Methanol Film

    Get PDF
    Environmental molecular beam experiments are used to examine water interactions with liquid methanol films at temperatures from 170 K to 190 K. We find that water molecules with 0.32 eV incident kinetic energy are efficiently trapped by the liquid methanol. The scattering process is characterized by an efficient loss of energy to surface modes with a minor component of the incident beam that is inelastically scattered. Thermal desorption of water molecules has a well characterized Arrhenius form with an activation energy of 0.47{\pm}0.11 eV and pre-exponential factor of 4.6 {\times} 10^(15{\pm}3) s^(-1). We also observe a temperature dependent incorporation of incident water into the methanol layer. The implication for fundamental studies and environmental applications is that even an alcohol as simple as methanol can exhibit complex and temperature dependent surfactant behavior.Comment: 8 pages, 5 figure
    corecore