8,907 research outputs found
Graph Theoretic Construction of Discrete Groups over p-adic Fields
This paper is originally designed as a part of revision of the author's
preprint math.AG/9908174 "P-adic Schwarzian triangle groups of Mumford type".
Recently, Yves Andr'e pointed out a flaw in that preprint; more precisely,
Proposition II there was not correct, and consequently, as he pointed out, some
triangle groups are missing (but only in p=2,3,5). I apologize to the readers,
and will release the other part soon by the original title. In this paper, we
concentrate on the constructive part, but more systematically and in more
general situation. More precisely, this paper presents a complete criterion for
an abstract tree of groups to be realized in the context of p-adic
uniformization. This criterion provides a practical way of constructing
finitely generated discrete subgroups in PGL(2,K) over a p-adic field K. In the
end of this paper, we will exhibit concrete examples of such construction,
which in particular shows that there exist infinitely many triangle groups.Comment: 14 pages, 2 figure
The Impact of Corporate Restructuring and Downsizing on the Managerial Careers of Minorities and Women: Lessons Learned from Nine Companies
Glass Ceiling ReportGlassCeilingBackground6ImpactofCorporateDownsizing.pdf: 1346 downloads, before Oct. 1, 2020.0-Pages_from_ImpactofCorporateRestructuringDownsizing.pdf: 87 downloads, before Oct. 1, 2020.1-Appendixfrom_ImpactofCorporateRestructuringDownsizing.pdf: 2958 downloads, before Oct. 1, 2020
Radon gas, useful for medical purposes, safely fixed in quartz
Radon gas is enclosed in quartz or glass ampules by subjecting the gas sealed at a low pressure in the ampules to an ionization process. This process is useful for preparing fixed radon sources for radiological treatment of malignancies, without the danger of releasing radioactive gases
Structural changes in cartilage and collagen studied by high temperature Raman spectroscopy
Understanding the high temperature behavior of collagen and collagenous tissue is important for surgical procedures and biomaterials processing for the food, pharmaceutical, and cosmetics industries. One primary event for proteins is thermal denaturation that involves unfolding the polypeptide chains while maintaining the primary structure intact. Collagen in the extracellular matrix of cartilage and other connective tissue is a hierarchical material containing bundles of triple-helical fibers associated with water and proteoglycan components. Thermal analysis of dehydrated collagen indicates irreversible denaturation at high temperature between 135°C and 200°C, with another reversible event at ∼60-80°C for hydrated samples. We report high temperature Raman spectra for freeze-dried cartilage samples that show an increase in laser-excited fluorescence interpreted as conformational changes associated with denaturation above 140°C. Spectra for separated collagen and proteoglycan fractions extracted from cartilage indicate the changes are associated with collagen. The Raman data also show appearance of new features indicating peptide bond hydrolysis at high temperature implying that molecular H2O is retained within the freeze-dried tissue. This is confirmed by thermogravimetric analysis that show 5-7 wt% H2O remaining within freeze-dried cartilage that is released progressively upon heating up to 200°C. Spectra obtained after exposure to high temperature and re-hydration following recovery indicate that the capacity of the denatured collagen to re-absorb water is reduced. Our results are important for revealing the presence of bound H2O within the collagen component of connective tissue even after freeze-drying and its role in denaturation that is accompanied by or perhaps preceded by breakdown of the primary polypeptide structure
Probing Grand Unification Through Neutrino Oscillations, Leptogenesis, and Proton Decay
Evidence in favor of supersymmetric grand unification including that based on
the observed family multiplet-structure, gauge coupling unification, neutrino
oscillations, baryogenesis, and certain intriguing features of quark-lepton
masses and mixings is noted. It is argued that attempts to understand (a) the
tiny neutrino masses (especially Delta m^2 (nu_2 -nu_3)), (b) the baryon
asymmetry of the universe (which seems to need leptogenesis), and (c) the
observed features of fermion masses such as the ratio m_b/m_tau, the smallness
of V_cb and the maximality of theta_{nu_mu-nu_tau}, seem to select out the
route to higher unification based on an effective string-unified G(224) =
SU(2)_L x SU(2)_R x SU(4)^c or SO(10)-symmetry, operative in 4D, as opposed to
other alternatives.
A predictive framework based on an effective SO(10) or G(224) symmetry
possessing supersymmetry is presented that successfully describes the masses
and mixings of all fermions including neutrinos. It also accounts for the
observed baryon asymmetry of the universe by utilizing the process of
leptogenesis, which is natural to this framework. It is argued that a
conservative upper limit on the proton lifetime within this
SO(10)/G(224)-framework, which is so far most successful, is given by (1/3-2) x
10^34 years. This in turn strongly suggests that an improvement in the current
sensitivity by a factor of five to ten (compared to SuperK) ought to reveal
proton decay. Implications of this prediction for the next-generation nucleon
decay and neutrino-detector are noted.Comment: 40 page, 3 figures. Conference proceedings from Erice School (Sept
2002), Neutrino Conference (Stony Brook, 2002), PASCOS Conference (Mumbai,
2003) Version 2: New references and some clarifications adde
Perceptions of Teachers: Effects of Principals Uses of Humor on Teacher Job Satisfaction.
The purpose of this study was to determine if teachers\u27 job satisfaction was greater when working for principals with higher perceived use of humor. The study also examined the effects of principals\u27 use of humor on perceived leadership effectiveness and level of personal relationship.
The researcher used a 36-question survey instrument to collect data. A population of 796 educators in a public school system in Northeast Tennessee was given an opportunity to participate in this research. There were 450 completed surveys (56%) returned.
There were 4 major findings from this study. Teachers reported that it was appropriate for principals to use humor in a school setting to a significant level (p \u3c 0.001). Data from the surveys also indicated that teachers had significantly higher reported job satisfaction (p \u3c 0.001) when working for principals who used humor when compared to principals who did not use humor regularly. The research also showed that teachers had significantly higher reported personal relationships (p \u3c 0.001) with principals who use humor regularly. In addition, teachers in this study rated leadership effectiveness significantly higher ( p \u3c 0.001) for principals who regularly used humor when compared to those who did not
Dark matter from cosmic defects on galactic scales?
We discuss the possible dynamical role of extended cosmic defects on galactic
scales, specifically focusing on the possibility that they may provide the dark
matter suggested by the classical problem of galactic rotation curves. We
emphasize that the more standard defects (such as Goto-Nambu strings) are
unsuitable for this task, but show that more general models (such as transonic
wiggly strings) could in principle have a better chance. In any case, we show
that observational data severely restricts any such scenarios.Comment: Submitted to Phys. Rev. D (Brief Reports). v2: Reference added and
some typos corrected, matches published versio
Neutron activation analysis traces copper artifacts to geographical point of origin
Impurities remaining in the metallic copper are identified and quantified by spectrographic and neutron activation analysis. Determination of the type of ore used for the copper artifact places the geographic point of origin of the artifact
Detection of solvents using a distributed fibre optic sensor
A fibre optic sensor that is capable of distributed detection of liquid solvents is presented. Sensor interrogation using optical time domain reflectometry (OTDR) provides the capability of locating solvent spills to a precision of ±2 m over a total sensor length that may extend to 20 km
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