Quark mass effects in high energy neutrino nucleon scattering

We evaluate the neutrino nucleon charged current cross section at next-to-leading order in quantum chromodynamic corrections in the variable flavor number scheme and the fixed flavor number scheme, taking into account quark masses. The number scheme dependence is largest at the highest energies considered here, $10^{12}$ GeV, where the cross sections differ by approximately 15 percent. We illustrate the numerical implications of the inconsistent application of the fixed flavor number scheme.Comment: 8 pages, 8 figures, v2: updated pdfs, version accepted for publicatio

Color dipole cross section and inelastic structure function

Instead of starting from a theoretically motivated form of the color dipole cross section in the dipole picture of deep inelastic scattering, we start with a parametrization of the deep inelastic structure function for electromagnetic scattering with protons, and then extract the color dipole cross section. Using the parametrizations of $F_2(\xi=x \ {\rm or}\ W^2,Q^2)$ by Donnachie-Landshoff and Block et al., we find the dipole cross section from an approximate form of the presumed dipole cross section convoluted with the perturbative photon wave function for virtual photon splitting into a color dipole with massless quarks. The color dipole cross section determined this way reproduces the original structure function within about 10\% for $0.1$ GeV$^2\leq Q^2\leq 10$ GeV$^2$. We discuss the large and small form of the dipole cross section and compare with other parameterizations.Comment: 11 pages, 12 figure

Methodological Considerations for Qualitative Research with Immigrant Populations: Lessons from Two Studies

Often, research strategies are guided by principles developed based on mainstream U.S. cultural norms. Immigrants, however, may differ in their cultural backgrounds and previous exposure to research. Commonly adopted research procedures, such as the informed consent process, may be culturally inappropriate for research with culturally diverse populations, and hence require cultural adaptations. Based on two qualitative studies, this paper describes the methodological issues encountered in the field when working with Chinese and Kenyan immigrants, and explains how these issues were resolved. Comparing and synthesizing experiences from the two studies, recommendations for methodological adaptations when working with immigrant populations are provided. Specifically, suggestions on how to prepare the research protocol, recruit participants, obtain informed consent, deal with unanticipated incidents during the research process, and choose the interview language(s) are discussed in depth

Forcing function control of Faraday wave instabilities in viscous shallow fluids

We investigate the relationship between the linear surface wave instabilities of a shallow viscous fluid layer and the shape of the periodic, parametric-forcing function (describing the vertical acceleration of the fluid container) that excites them. We find numerically that the envelope of the resonance tongues can only develop multiple minima when the forcing function has more than two local extrema per cycle. With this insight, we construct a multi-frequency forcing function that generates at onset a non-trivial harmonic instability which is distinct from a subharmonic response to any of its frequency components. We measure the corresponding surface patterns experimentally and verify that small changes in the forcing waveform cause a transition, through a bicritical point, from the predicted harmonic short-wavelength pattern to a much larger standard subharmonic pattern. Using a formulation valid in the lubrication regime (thin viscous fluid layer) and a WKB method to find its analytic solutions, we explore the origin of the observed relation between the forcing function shape and the resonance tongue structure. In particular, we show that for square and triangular forcing functions the envelope of these tongues has only one minimum, as in the usual sinusoidal case.Comment: 12 pages, 10 figure

Neutrino Cross Sections: Interface of shallow- and deep-inelastic scattering for collider neutrinos

Neutrino experiments in a Forward Physics Facility at the Large Hadron Collider can measure neutrino and antineutrino cross sections for energies up to a few TeV. For neutrino energies below 100 GeV, the inelastic cross section evaluations have contributions from weak structure functions at low momentum transfers and low hadronic final state invariant mass. To evaluate the size of these contributions to the neutrino cross section, we use a parametrization of the electron-proton structure function, adapted for neutrino scattering, augmented with a correction to account for the partial conservation of the axial vector current, and normalized to structure functions evaluated at next-to-leading order in QCD, with target mass corrections and heavy quark corrections. We compare our results with other approaches to account for this kinematic region in neutrino cross section for energies between 10--1000 GeV on isoscalar nucleon and iron targets.Comment: 16 pages, 10 figure

CXCL7-Mediated Stimulation of Lymphangiogenic Factors VEGF-C, VEGF-D in Human Breast Cancer Cells

Increased expression of lymphangiogenesis factors VEGF-C/D and heparanase has been correlated with the invasion of cancer. Furthermore, chemokines may modify matrix to facilitate metastasis, and they are associated with VEGF-C and heparanase. The chemokine CXCL7 binds heparin and the G-protein-linked receptor CXCR2. We investigated the effect of CXCR2 blockade on the expression of VEGF-C/D, heparanase, and on invasion. CXCL7 siRNA and a specific antagonist of CXCR2 (SB225002) were used to treat CXCL7 stably transfected MCF10AT cells. Matrigel invasion assays were performed. VEGF-C/D expression and secretion were determined by real-time PCR and ELISA assay, and heparanase activity was quantified by ELISA. SB225002 blocked VEGF-C/D expression and secretion (P < .01). CXCL7 siRNA knockdown decreased heparanase (P < .01). Both SB225002 and CXCL7 siRNA reduced the Matrigel invasion (P < .01). The MAP kinase signaling pathway was not involved. The CXCL7/CXCR2 axis is important for cell invasion and the expression of VEGF-C/D and heparanase, all linked to invasion