4,391 research outputs found
Can the Couplings in the Fermion-Higgs Sector of the Standard Model be Strong?
We present results for the renormalized quartic self-coupling and
the Yukawa coupling in a lattice fermion-Higgs model with two SU(2)
doublets, mostly for large values of the bare couplings. One-component
(`reduced') staggered fermions are used in a numerical simulation with the
Hybrid Monte Carlo algorithm. The fermion and Higgs masses and the renormalized
scalar field expectation value are computed on lattices, where
ranges from to . In the scaling region these quantities are found to
have a dependence, which is used to determine their values in the
infinite volume limit. We then calculate the and from their
tree level definitions in terms of the masses and renormalized scalar field
expectation value, extrapolated to infinite volume. The scalar field
propagators can be described for momenta up to the cut-off by one fermion loop
renormalized perturbation theory and the results for and come
out to be close to the tree level unitarity bounds. There are no signs that are
in contradiction with the triviality of the Yukawa and quartic self-coupling.Comment: 36 pages + 12 postscript figures (appended), Amsterdam ITFA 92-23,
HLRZ Juelich 92-58, UCSD/PTH 92-3
Connection between slow and fast dynamics of molecular liquids around the glass transition
The mean-square displacement (MSD) was measured by neutron scattering at
various temperatures and pressures for a number of molecular glass-forming
liquids. The MSD is invariant along the glass-transition line at the pressure
studied, thus establishing an ``intrinsic'' Lindemann criterion for any given
liquid. A one-to-one connection between the MSD's temperature dependence and
the liquid's fragility is found when the MSD is evaluated on a time scale of
approximately 4 nanoseconds, but does not hold when the MSD is evaluated at
shorter times. The findings are discussed in terms of the elastic model and the
role of relaxations, and the correlations between slow and fast dynamics are
addressed.Comment: accepted by Phys Rev E (2010
Summary of Toxicological Data for Aquatic Organisms of Illinois
The data presented in this report contain Information on toxicity testing performed on organisms that could be found In aquatic habitats in Illinois. To compile this information a thorough list of all aquatic organisms in Illinois was required. This was constructed through literature searches and personal communication with scientists who collect and identify Illinois aquatic specimens. Each species name was used to search a database which contained toxicity information on aquatic organisms. No toxicological Information was found for many Illinois species. For most organisms, all
available information retrieved from the database is presented. For species on which extensive toxicological research has been performed, data showing 96 hour LC50 or EC50
values and chronic testing values constitute the bulk of the records. In addition to records detailing toxicity values and experimental conditions, a list of tested chemical compounds and organisms is included.
Literature citing observations and identification of aquatic organisms within Illinois was the most valuable resource in compiling a list of Illinois aquatic species.
Staff of the Illinois Natural History Survey were helpful in recommending the most useful publications, making available their own field lists, and helping to update taxonomy and nomenclature from older reports. In particular we would like to acknowledge Don Webb, Larry Page, Warren Brigham, Mark Wetzel, Kevin Cummings, and Allison Brigham from the INHS Faunistics section and Michael Henebry from the section of Aquatic Biology.
To retrieve toxicity data on the aquatic organisms of Illinois, a Chemical Information System, Inc. database, AQUIRE
(Aquatic Information Retrieval System), was employed. AQUIRE contains data extracted from publications dealing with the toxic effects of chemical substances on aquatic organisms. Each Latin species name from the compiled Illinois list was used to search records in the database. If AQUIRE matched a record with the species name, the record was
stored. If there were an excessive number of matching records, the search was narrowed by specifying particular regimens and/or effective endpoint types. Ultimately a printout of the records pertaining to each organism was produced. The data contained In this report are duplications of the
AQUIRE records obtained for Illinois organisms. The taxonomy, habitat, and Illinois distribution is listed immediately preceding the AQUIRE records compiled for
each species. These records have been substantially reduced from their original size and are arranged by chemical compound
in alphabetical and/or numerical order.published or submitted for publicationis peer reviewe
No strong coupling regime in the fermion-Higgs sector of the standard model
We present results for the renormalized quartic self-coupling \lm_R and the
renormalized Yukawa coupling in a fermion-Higgs model with two SU(2)
doublets, indicating that these couplings are not very strong.Comment: 4 pages, 4 postscript figures (appended), ITFA-92-32, HLRZ-92-92,
UCSD/PTH 92-43, Contribution to the Conference Lattice'9
Numerical simulation of heavy fermions in an SU(2)_L x SU(2)_R symmetric Yukawa model
An exploratory numerical study of the influence of heavy fermion doublets on
the mass of the Higgs boson is performed in the decoupling limit of a chiral
symmetric Yukawa model with mirror fermions. The
behaviour of fermion and boson masses is investigated at infinite bare quartic
coupling on , and lattices. A first
estimate of the upper bound on the renormalized quartic coupling as a function
of the renormalized Yukawa-coupling is given.Comment: 15 pp + 11 Figures appended as Postscript file
Development of hot drawing process for nitinol tube
In recent years, Nitinol, near-equiatomic nickel-titanium alloys, have found growing applications in medical technology and joining technology, due to their special characteristics such as shape memory, superplasticity and biocompatibility. The production of Nitinol tube cost-effectively remains a technical challenge. In this paper, we describe a hot drawing process for Nitinol tube production. A Nitinol tube blank and a metal core are assembled together. The assembly is hot drawn for several passes to a final diameter. The metal core is then plastically stretched to reduce its diameter and removed from the tube. Hot drawing process has been applied to Ni50.7Ti and Ni47Ti44Nb9 alloys. Nitinol tubes of 13.6 mm outer diameter and 1 mm wall thickness have been successfully produced from a tube blank of 20 mm outer diameter and 3.5 mm thickness
Chiral phase transition in a lattice fermion--gauge--scalar model with U(1) gauge symmetry
The chiral phase transition induced by a charged scalar field is investigated
numerically in a lattice fermion-gauge-scalar model with U(1) gauge symmetry,
proposed recently as a model for dynamical fermion mass generation. For very
strong gauge coupling the transition is of second order and its scaling
properties are very similar to those of the Nambu--Jona-Lasinio model. However,
in the vicinity of the tricritical point at somewhat weaker coupling, where the
transition changes the order, the scaling behavior is different. Therefore it
is worthwhile to investigate the continuum limit of the model at this point.Comment: 20 pages, latex2e, 15 PostScript figures included, all files tared,
compressed and uudecode
A Self-Study on Preparing Future School Leaders
William C. Frick is assistant professor in the Department of Educational Leadership and Policy Studies, Rainbolt College of Education, University of Oklahoma. He holds a Ph.D. in educational theory and policy from the Pennsylvania State University. His research interests include valuation, ethics, and moral school leadership practices; school and community revitalization; and school district reform.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
A Formal Administrator Mentoring Program: Perceived Learning Benefits and Insights into Leadership Well-being
The purpose of this research was to investigate a formal principal mentoring program and report on perceived learning benefits and well-being of participants. The study highlights aspects of the mentoring relationship evidenced in the explicit and intentional development of school leaders. The empirical investigation used qualitative-naturalistic inquiry methods. Data were collected primarily through in-depth, focused participant interviews. The findings of this study revealed both the “what” and “how” of perceived benefits within formal mentoring relationships under the direction of a state-wide programmatic initiative. Of particular interest was the role of social learning through reflective activity and results of occupational well-being. A truthful representation of aspects of mentoring relationships between novice and mentor principals within formal programming provided insights into how novice learning supports their well-being. Implications for the development and retention of principals are considered
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