1,904 research outputs found
Character-theoretic Techniques for Near-central Enumerative Problems
The centre of the symmetric group algebra has
been used successfully for studying important problems in enumerative
combinatorics. These include maps in orientable surfaces and ramified covers of
the sphere by curves of genus , for example. However, the combinatorics of
some equally important -factorization problems forces
elements in to be distinguished. Examples of such problems
include the star factorization problem, for which and the enumeration of
2-cell embeddings of dipoles with two distinguished edges
\cite{VisentinWieler:2007} associated with Berenstein-Maldacena-Nastase
operators in Yang-Mills theory \cite{ConstableFreedmanHeadrick:2002}, for which
Although distinguishing these elements obstructs the use of central
methods, these problems may be encoded algebraically in the centralizer of
with respect to the subgroup
We develop methods for studying these problems for and demonstrate their
efficacy on the star factorization problem. In a subsequent paper
\cite{JacksonSloss:2011}, we consider a special case of the the above dipole
problem by means of these techniques
Corn Disease Update
Goss\u27s Bacterial Wilt and Blight ... Symptoms ... Management ... 2011 Survey ... Literature Cited
Gray Leaf Spot
Seedling Diseases and Stalk/Crown Root Diseases
More Resource
Corn Disease Update
Goss\u27s Bacterial Wilt and Blight ... Symptoms ... 2011 Survey results ... New alternate hosts identified ... Goss\u27s Wilt Management Strategies ... More Resources ... Literature Cited
Aspergillus Ear Rot and Aflatoxin Contaminated Grain ... Table 1. FDA Action Levels for Aflatoxin in Feed and Food ... Testing for Aflatoxin ... High risk factors for aflatoxin contamination in corn ... Scouting for Aspergillus Ear Rot ... Harvest and Storage ... More Resources
Stalk Rot Diseases ... Scouting for Stalk Rot Diseases ... Management ... More Resource
Integration of HIV Care with Primary Health Care Services: Effect on Patient Satisfaction and Stigma in Rural Kenya.
HIV departments within Kenyan health facilities are usually better staffed and equipped than departments offering non-HIV services. Integration of HIV services into primary care may address this issue of skewed resource allocation. Between 2008 and 2010, we piloted a system of integrating HIV services into primary care in rural Kenya. Before integration, we conducted a survey among returning adults ≥18-year old attending the HIV clinic. We then integrated HIV and primary care services. Three and twelve months after integration, we administered the same questionnaires to a sample of returning adults attending the integrated clinic. Changes in patient responses were assessed using truncated linear regression and logistic regression. At 12 months after integration, respondents were more likely to be satisfied with reception services (adjusted odds ratio, aOR 2.71, 95% CI 1.32-5.56), HIV education (aOR 3.28, 95% CI 1.92-6.83), and wait time (aOR 1.97 95% CI 1.03-3.76). Men's comfort with receiving care at an integrated clinic did not change (aOR = 0.46 95% CI 0.06-3.86). Women were more likely to express discomfort after integration (aOR 3.37 95% CI 1.33-8.52). Integration of HIV services into primary care services was associated with significant increases in patient satisfaction in certain domains, with no negative effect on satisfaction
Four Common \u3ci\u3eSetaria\u3c/i\u3e Species Are Alternative Hosts for \u3ci\u3eClavibacter michiganensis\u3c/i\u3e subsp. \u3ci\u3enebraskensis\u3c/i\u3e, Causal Agent of Goss\u27s Bacterial Wilt and Blight of Corn
Goss’s bacterial wilt and blight, caused by Clavibacter michiganensis subsp. nebraskensis (Cmn), has reemerged as an important disease of Zea mays (corn) in the U.S. Midwest. Results from a 2011 multistate survey indicated that Setaria spp. (foxtail) were often present in corn fields with a history of Cmn. The objective of this research was to determine if Setaria spp. that are common in the Midwest are susceptible to infection by Cmn. In the greenhouse, seedlings of four Setaria spp., including S. viridis (green foxtail), S. faberi (giant foxtail), S. verticillata (bristly foxtail), and S. pumila (yellow foxtail), and Zea mays (Golden Cross Bantam sweet corn, GCB) were inoculated with a suspension of 1.0 × 107 bacteria cells. The trial was arranged in a randomized complete block design and repeated once. Percent of symptomatic leaf area was visually estimated eight days after inoculation. S. faberi exhibited the highest levels of disease among the four Setaria spp., with disease incidence similar to what was observed on Z. mays. S. viridis was the next most susceptible. Symptoms were also observed on S. viridis, S. verticillata, and were lowest for S. pumila. Bacterial streaming was confirmed microscopically and Cmn was reisolated from the four Setaria species. Results indicate that these four Setaria spp. are susceptible to Cmn, thus serving as potential sources of inoculum
Noncovariant gauge fixing in the quantum Dirac field theory of atoms and molecules
Starting from the Weyl gauge formulation of quantum electrodynamics (QED),
the formalism of quantum-mechanical gauge fixing is extended using techniques
from nonrelativistic QED. This involves expressing the redundant gauge degrees
of freedom through an arbitrary functional of the gauge-invariant transverse
degrees of freedom. Particular choices of functional can be made to yield the
Coulomb gauge and Poincar\'{e} gauge representations. The Hamiltonian we derive
therefore serves as a good starting point for the description of atoms and
molecules by means of a relativistic Dirac field. We discuss important
implications for the ontology of noncovariant canonical QED due to the gauge
freedom that remains present in our formulation.Comment: 8 pages, 0 figure
Evidence for variable selective pressures at MC1R
It is widely assumed that genes that influence variation in skin and hair pigmentation are under selection. To date,the melanocortin 1 receptor (MC1R) is the only gene identified that explains substantial phenotypic variance inhuman pigmentation. Here we investigate MC1R polymorphism in several populations, for evidence of selection.We conclude that MC1R is under strong functional constraint in Africa, where any diversion from eumelanin production (black pigmentation) appears to be evolutionarily deleterious. Although many of the MC1R amino acid variants observed in non-African populations do affect MC1R function and contribute to high levels of MC1R diversity in Europeans, we found no evidence, in either the magnitude or the patterns of diversity, for its enhancement by selection; rather, our analyses show that levels of MC1R polymorphism simply reflect neutral expectations underrelaxation of strong functional constraint outside Africa
Quantum Electrodynamics near a Huttner-Barnett dielectric
We build up a consistent theory of quantum electrodynamics in the presence of
macroscopic polarizable media. We use the Huttner-Barnett model of a dispersive
and absorbing dielectric medium and formulate the theory in terms of
interacting quantum fields. We integrate out the damped polaritons by using
diagrammatic techniques and find an exact expression for the displacement field
(photon) propagator in the presence of a dispersive and absorbing dielectric
half-space. This opens a new route to traceable perturbative calculations of
the same kind as in free-space quantum electrodynamics. As a worked-through
example we consider the interaction of a neutral atom with a dispersive and
absorbing dielectric half-space. For that we use the multipolar coupling
of the atomic dipole moment to the
electromagnetic displacement field. We apply the newly developed formalism to
calculate the one-loop correction to the atomic electron propagator and find
the energy-level shift and changes in the spontaneous decay rates for a neutral
atom close to an absorptive dielectric mirror.Comment: 25 pages, 4 figure
Parents and School Children Talking about Food and Drink Choices – A Focus Group Study
Peer reviewedPublisher PD
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