719 research outputs found

    Electroweak Precision Constraints on the Littlest Higgs Model with T Parity

    Full text link
    We compute the leading corrections to the properties of W and Z bosons induced at the one-loop level in the SU(5)/SO(5) Littlest Higgs model with T parity, and perform a global fit to precision electroweak data to determine the constraints on the model parameters. We find that a large part of the model parameter space is consistent with data. Values of the symmetry breaking scale as low as 500 GeV are allowed, indicating that no significant fine tuning in the Higgs potential is required. We identify a region within the allowed parameter space in which the lightest T-odd particle, the partner of the hypercharge gauge boson, has the correct relic abundance to play the role of dark matter. In addition, we find that a consistent fit to data can be obtained for large values of the Higgs mass, up to 800 GeV, due to the possibility of a partial cancellation between the contributions to the T parameter from Higgs loops and new physics.Comment: 23 pages, 9 figures. Minor correction

    Treatment and Disposal of Potato Wastewater by Irrigation

    Get PDF
    Irrigation with potato processing waste water was studied for 3 years at five locations in southern Idaho. Three of the potato processors surface irrigated and two sprinkled land planted to perennial grasses. The processing season began in October and continued into the following summer. Samples of 24-hour composited waste water and soil water, extracted from depths of 15 to 150 cm, were obtained monthly throughout the year. Analyses were made on all water samples of sufficient volume for chemical oxygen demand (COD), NO3 , total N, total P, ortho P, hydrolyzable P, K, Na, Ca, Mg, Cl, HCO3 , SO4 , electrical conductivity, and pH. Water applications ranged from 160 to 490 cm per year, total N from 1,000 to 2,200 kg, P from 150 to 630 kg, and K from 2,250 to 6,700 kg K/hectare year. COD decreased 95 to 100 percent after passage of the water through 150 cm of soil because of biological activity and filtration. Nitrates were low in one field with a shallow water table because of denitrification that resulted from low redox potentials. Phosphorus concentrations increased 50 to 100 parts per million in the surface 30 cm of soil but not measurably below that depth. K, Na, Ca, and Mg changed in proportion to the amounts applied in the waste water. Irrigation with potato processing waste water provides a means of utilizing part of the nutrients that. would otherwise be wasted and solves a difficult environmental pollution problem

    Epitope enhancement of a CD4 HIV epitope toward the development of the next generation HIV vaccine

    Get PDF
    Virus-specific CD4+ T cell help and CD8+ cytotoxic T cell responses are critical for maintenance of effective immunity in chronic viral infections. The importance of CD4+ T cells has been documented in HIV infection. To investigate whether a stronger CD4+ T cell response can be induced by modifications to enhance the T1 epitope, the first CD4+ T cell epitope discovered in HIV-1-gp120, we developed a T1-specific CD4+ T cell line from a healthy volunteer immunized with a canarypox vector expressing gp120 and boosted with recombinant gp120. This T1-specific CD4+ T cell line was restricted to DR13, which is common in U.S. Caucasians and African-Americans and very frequent in Africans. Peptides with certain amino acid substitutions in key positions induced enhanced specific CD4+ T cell proliferative responses at lower peptide concentration than the original epitope. This relatively conserved CD4 epitope improved by the epitope enhancement strategy could be a component of a more effective second generation vaccine construct for HIV infection

    Competition of nuclear factor-erythroid 2 factors related transcription factor isoforms, Nrf1 and Nrf2, in antioxidant enzyme induction

    Get PDF
    AbstractAlthough the Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2) regulated expression of multiple antioxidant and cytoprotective genes through the electrophile responsive element (EpRE) is well established, interaction of Nrf2/EpRE with Nrf1, a closely-related transcription factor, is less well understood. Due to either proteolysis or alternative translation, Nrf1 has been found as proteins of varying size, p120, p95, and p65, which have been described as either activators of EpRE or competitive inhibitors of Nrf2. We investigated the effect of Nrf1 on EpRE-regulated gene expression using the catalytic and modifier subunits of glutamate cysteine ligase (GCLC and GCLM) as models and explored the potential role of Nrf1 in altering their expression in aging and upon chronic exposure to airborne nano-sized particulate matter (nPM). Nrf1 knockout resulted in the increased expression of GCLC and GCLM in human bronchial epithelial (HBE1) cells. Overexpression Nrf2 in combination with either p120 or p65 diminished or failed to further increase the GCLC- and GLCM-EpRE luciferase activity. All known forms of Nrf1 protein, remained unchanged in the lungs of mice with age or in response to nPM. Our study shows that Nrf1 could inhibit EpRE activity in vitro, whereas the precise role of Nrf1 in vivo requires further investigations. We conclude that Nrf1 may not be directly responsible for the loss of Nrf2-dependent inducibility of antioxidant and cytoprotective genes observed in aged animals

    Scalar Dark Matter From Theory Space

    Get PDF
    The scalar dark matter candidate in a prototypical theory space little Higgs model is investigated. We review all details of the model pertinent to dark matter. We perform a thermal relic density calculation including couplings to the gauge and Higgs sectors of the model. We find two regions of parameter space that give acceptable dark matter abundances. The first region has a dark matter candidate with a mass of order 100 GeV, the second region has a heavy candidate with a mass greater than about 500 GeV$. The dark matter candidate in either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby constituting a WIMP (weakly interacting massive particle).Comment: 18 pages, 2 figures, version to appear in PR

    Fermions on an Interval: Quark and Lepton Masses without a Higgs

    Full text link
    We consider fermions on an extra dimensional interval. We find the boundary conditions at the ends of the interval that are consistent with the variational principle, and explain which ones arise in various physical circumstances. We apply these results to higgsless models of electroweak symmetry breaking, where electroweak symmetry is not broken by a scalar vacuum expectation value, but rather by the boundary conditions of the gauge fields. We show that it is possible to find a set of boundary conditions for bulk fermions that would give a realistic fermion mass spectrum without the presence of a Higgs scalar, and present some sample fermion mass spectra for the standard model quarks and leptons as well as their resonances.Comment: LaTeX, 36 pages, 5 figure

    Re-storying and visualizing the changing entrepreneurial identities of Bill Gates and Richard Branson.

    Get PDF
    The storytelling in textual and visual re-constructions of Bill Gates and Richard Branson by their organizations produces entrepreneurial identities bound into particular social power-knowledge relations. Our purpose is to examine how these organizations, and their critics, mobilize storytelling in acts of re-storying (enlivening) or re-narrating (branding a monologic) practices using Internet technologies to invite viewers to frame the world of entrepreneurship. We use visual discourse and storytelling methods to analyze how Microsoft and Virgin Group use various kinds of entrepreneurial images and textual narratives to re-narrate and produce particular brands of capitalism. These organizations' scoptic regimes of representation are contested in counter-visualizing and counterstory practices of external stakeholders. We suggest that the image and textual practices of storytelling have changed as both entrepreneurs court philanthropic and social entrepreneur identity markers. Our contribution to entrepreneurial identity is to apply double and multiple narrations, the appropriation of another's narrative words (or images) into another's narrative, and relate such storytelling moves to visuality

    Junior-elite football: time to re-position talent identification?

    Get PDF
    There remains limited understanding of the processes and factors which contribute to young footballers being identified as talented. Talent identification is imperative for the development of future elite performers, though most studies conflate talent identification and talent development. Moreover, within the literature there is a lack of operational or procedural distinction for talent identification, causing issues for those researching and working within applied contexts. This paper sought to clarify issues related to talent identification in junior-elite football, offering a review of the extant literature and proposing future directions for applied research. There are unanswered questions associated with how scouts, recruitment staff, and coaches decide what constitutes talent and the importance placed on particular attributes during that process. We suggest that further research into the ascribed processes, observations and perceptions of those involved in talent identification is needed to provide more sound understanding of the talent identification process in football
    • …
    corecore