476 research outputs found

    An algebro-geometric proof of Witten's conjecture

    Full text link
    We present a new proof of Witten's conjecture. The proof is based on the analysis of the relationship between intersection indices on moduli spaces of complex curves and Hurwitz numbers enumerating ramified coverings of the 2-sphere.Comment: 12 pages, no figure

    A 14-day ground-based hypokinesia study in nonhuman primates: A compilation of results

    Get PDF
    A 14 day ground based hypokinesia study with rhesus monkeys was conducted to determine if a spaceflight of similar duration might affect bone remodeling and calcium homeostatis. The monkeys were placed in total body casts and sacrificed either immediately upon decasting or 14 days after decasting. Changes in vertebral strength were noted and further deterioration of bone strength continued during the recovery phase. Resorption in the vertebrae increased dramatically while formation decreased. Cortical bone formation was impaired in the long bones. The immobilized animals showed a progressive decrease in total serum calcium which rebounded upon remobilization. Most mandibular parameters remained unchanged during casting except for retardation of osteon birth or maturation rate and density distribution of matrix and mineral moieties

    Attenuated total reflection-FT-IR spectroscopic imaging of protein crystallization

    Get PDF
    Protein crystallization is of strategic and commercial relevance in the post-genomic era because of its pivotal role in structural proteomics projects. Although protein structures are crucial for understanding the function of proteins and to the success of rational drug design and other biotechnology applications, obtaining high quality crystals is a major bottleneck to progress. The major means of obtaining crystals is by massive-scale screening of a target protein solution with numerous crystallizing agents. However, when crystals appear in these screens, one cannot easily know if they are crystals of protein, salt, or any other molecule that happens to be present in the trials. We present here a method based on Attenuated Total Reflection (ATR)-FT-IR imaging that reliably identifies protein crystals through a combination of chemical specificity and the visualizing capability of this approach, thus solving a major hurdle in protein crystallization. ATR-FT-IR imaging was successfully applied to study the crystallization of thaumatin and lysozyme in a high-throughput manner, simultaneously from six different solutions. This approach is fast as it studies protein crystallization in situ and provides an opportunity to examine many different samples under a range of conditions

    From Hurwitz numbers to Kontsevich-Witten tau-function: a connection by Virasoro operators

    Full text link
    In this letter,we present our conjecture on the connection between the Kontsevich--Witten and the Hurwitz tau-functions. The conjectural formula connects these two tau-functions by means of the GL()GL(\infty) group element. An important feature of this group element is its simplicity: this is a group element of the Virasoro subalgebra of gl()gl(\infty). If proved, this conjecture would allow to derive the Virasoro constraints for the Hurwitz tau-function, which remain unknown in spite of existence of several matrix model representations, as well as to give an integrable operator description of the Kontsevich--Witten tau-function.Comment: 13 page

    Models of Neutrino Masses and Baryogenesis

    Get PDF
    Majorana masses of the neutrino implies lepton number violation and is intimately related to the lepton asymmetry of the universe, which gets related to the baryon asymmetry of the universe in the presence of the sphalerons during the electroweak phase transition. Assuming that the baryon asymmetry of the universe is generated before the electroweak phase transition, it is possible to dicriminate different classes of models of neutrino masses. While see-saw mechanism and the triplet higgs mechanism are preferred, the Zee-type radiative models and the R-parity breaking models requires additional inputs to generate baryon asymmetry of the universe during the electroweak phase transition.Comment: 27 pages including 5 figures; Review article for Pramana: the Indian Journal of Physic

    High Resolution CO Imaging of the Molecular Disk around the jets in KjPN 8

    Full text link
    We report high resolution (2.5 arcsec) CO J=1-0 line imaging which confirms the presence of a molecular disk around the origin of the spectacular, 14 arcmin times 4 arcmin, episodic jets in the planetary nebula KjPn 8. The disk is 30 arcsec in diameter with an expansion velocity of approximately 7 km/s. The axis of the disk is aligned with the youngest and fastest (approximately 300 km/s) of the bipolar jets, and there is evidence for interaction between the jets and the disk material. The inner 4 arcsec of the disk are photo-ionized by the central star. The disk-jet system dominates the environment of this young nebula, and should govern the morphology of KjPn 8 as it evolves to become fully ionized.Comment: 15 pages, 4 figures, accepted for publication in Astrophysical Journal Letter

    Baryogenesis through R-parity violation

    Get PDF
    We consider generation of baryon asymmetry of the universe through RR-parity violation in a scenario in which out-of-equilibrium condition is satisfied by making the electroweak phase transition to be first order. We study all the RR-parity violating interaction which can generate (BL)(B-L) asymmetry which then converts to baryon asymmetry of the universe. We demonstrate that CP--violating sfermion deudy all the RR-parity violating interaction which can generate (BL)(B-L) asymmetry which then converts to baryon asymmetry of the universe. We demonstrate that CP--violating sfermion decays contribute more than that of the neutralino decays in the generation of (BL)(B-L) asymmetry.Comment: 25 pages latex file (containing six eps files

    BGWM as Second Constituent of Complex Matrix Model

    Full text link
    Earlier we explained that partition functions of various matrix models can be constructed from that of the cubic Kontsevich model, which, therefore, becomes a basic elementary building block in "M-theory" of matrix models. However, the less topical complex matrix model appeared to be an exception: its decomposition involved not only the Kontsevich tau-function but also another constituent, which we now identify as the Brezin-Gross-Witten (BGW) partition function. The BGW tau-function can be represented either as a generating function of all unitary-matrix integrals or as a Kontsevich-Penner model with potential 1/X (instead of X^3 in the cubic Kontsevich model).Comment: 42 page
    corecore