3,799 research outputs found

    ANOMALOUS GAUGE BOSON INTERACTIONS

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    We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge boson self-interactions. If the energy scale of the new physics is ∌1\sim 1 TeV, these low energy anomalous couplings are expected to be no larger than O(10−2){\cal O}(10^{-2}). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.Comment: 53 pages with 17 embedded figures, LaTeX, uses axodraw.sty, figures available on request. The complete paper, is available at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z or http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z Summary of the DPF Working Subgroup on Anomalous Gauge Boson Interactions of the DPF Long Range Planning Stud

    Proper-time Resolution Function for Measurement of Time Evolution of B Mesons at the KEK B-Factory

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    The proper-time resolution function for the measurement of the time evolution of B mesons with the Belle detector at KEKB is studied in detail. The obtained resolution function is applied to the measurement of B meson lifetimes, the B0-B0bar oscillation frequency and time-dependent CP asymmetries.Comment: 25 pages, 18 figures, to be published in NIM A, replaced with revised versio

    Synchronization of Coupled Nonidentical Genetic Oscillators

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    The study on the collective dynamics of synchronization among genetic oscillators is essential for the understanding of the rhythmic phenomena of living organisms at both molecular and cellular levels. Genetic oscillators are biochemical networks, which can generally be modelled as nonlinear dynamic systems. We show in this paper that many genetic oscillators can be transformed into Lur'e form by exploiting the special structure of biological systems. By using control theory approach, we provide a theoretical method for analyzing the synchronization of coupled nonidentical genetic oscillators. Sufficient conditions for the synchronization as well as the estimation of the bound of the synchronization error are also obtained. To demonstrate the effectiveness of our theoretical results, a population of genetic oscillators based on the Goodwin model are adopted as numerical examples.Comment: 16 pages, 3 figure

    Clocking hadronization in relativistic heavy ion collisions with balance functions

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    A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-stage hadronization is characterized by tightly correlated charge/anticharge pairs when measured as a function of relative rapidity.Comment: 5 pages, 3 figure

    Development of a dose distribution shifter to fit inside the collimator of a Boron Neutron Capture Therapy irradiation system to treat superficial tumours

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    The Kansai BNCT Medical Center has a cyclotron based epithermal neutron source for clinical Boron Neutron Capture Therapy. The system accelerates a proton to an energy of 30 MeV which strikes a beryllium target producing fast neutrons which are moderated down to epithermal neutrons for BNCT use. While clinical studies in the past have shown BNCT to be highly effective for malignant melanoma of the skin, to apply BNCT for superficial lesions using this system it is necessary to shift the thermal neutron distribution so that the maximum dose occurs near the surface. A dose distribution shifter was designed to fit inside the collimator to further moderate the neutrons to increase the surface dose and reduce the dose to the underlying normal tissue. Pure polyethylene was selected, and a Monte Carlo simulation was performed to determine the optimum thickness of the polyethylene slab. Compared with the original neutron beam, the shifter increased the thermal neutron flux at the skin by approximately 4 times. The measured and simulated central axis depth distribution and off axis distribution of the thermal neutron flux were found to be in good agreement. Compared with a 2 cm thick water equivalent bolus, a 26% increase in the thermal neutron flux at the surface was obtained, which would reduce the treatment time by approximately 29%. The DDS is a safe, simple and an effective tool for the treatment of superficial tumours for BNCT if an initially fast neutron beam requires moderation to maximise the thermal neutron flux at the tissue surface

    Scale Dependence of Halo Bispectrum from Non-Gaussian Initial Conditions in Cosmological N-body Simulations

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    We study the halo bispectrum from non-Gaussian initial conditions. Based on a set of large NN-body simulations starting from initial density fields with local type non-Gaussianity, we find that the halo bispectrum exhibits a strong dependence on the shape and scale of Fourier space triangles near squeezed configurations at large scales. The amplitude of the halo bispectrum roughly scales as fnl2f_nl^2. The resultant scaling on the triangular shape is consistent with that predicted by Jeong & Komatsu based on perturbation theory. We systematically investigate this dependence with varying redshifts and halo mass thresholds. It is shown that the fnlf_nl dependence of the halo bispectrum is stronger for more massive haloes at higher redshifts. This feature can be a useful discriminator of inflation scenarios in future deep and wide galaxy redshift surveys.Comment: 27 pages, 10 figures; revised argument in section 6, added appendix C, JCAP accepted versio

    Stability and enzymatic studies with omeprazole: hydroxypropyl-ÎČ-cyclodextrin

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    The original publication is available at www.springerlink.com. A publicação original está disponível em www.springerlink.comOmeprazole (OME) exhibits low stability to light, heat and humidity. In stress conditions OME stability should improve under inclusion complex form with hydroxypropyl-b-cyclodextrin (HPbCD). Stability of OME, its physical mixture (PM) with HPbCD and OME:HPbCD inclusion complex was assessed during 60 days. The inclusion complexes were prepared by kneading and freezedrying techniques and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). A molecular modelling was also held to predict the most probable tridimensional conformation of inclusion complex OME:HPbCD. The inhibitory activity of free and complexed OME on selected enzymes, namely, papain (protease model of the proton pump) and acetylcholinesterase (enzyme present in cholinergic neurons and also involved in Alzheimer’s disease) was compared. The results obtained show that HPbCD do not protect against OME degradation, in any prepared powder, in the presence of light, heat and humidity. This may indicate that the reactive group of OME is not included in the HPbCD cavity. This fact is supported by molecular modelling data, which demonstrated that 2-pyridylmethyl group of OME is not included into the cyclodextrin cavity. In relation to enzymatic assays it was observed that free OME and OME in the binary systems showed identical inhibitory activity on papain and acethylcolinesterase, concluding that HPbCD do not affect OME activity on these two enzymes

    Better, faster, more versatile NMR diffusion measurements

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    The range of applications and versatility of NMR diffusion measurements [1,2] increase with the speed, accuracy, and the practical lower concentration limits that can be used. For example, faster measurements expand the horizons of diffusion measurements to study reaction kinetics [3,4], as well as simply increasing throughput. Our group has been investigating various approaches for improving the performance of NMR diffusion measurements. Here we present some of our recent advances
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