719 research outputs found
Genetic instruments with too many strings: acknowledging pleiotropy and population structure in Mendelian randomization studies
Electroweak Precision Constraints on the Littlest Higgs Model with T Parity
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
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
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
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
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
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.
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?
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
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