1,918 research outputs found
Syzygies, multigraded regularity and toric varieties
Using multigraded Castelnuovo-Mumford regularity, we study the equations
defining a projective embedding of a variety X. Given globally generated line
bundles B_1, ..., B_k on X and integers m_1, ..., m_k, consider the line bundle
L := B_1^m_1 \otimes ... \otimes B_k^m_k. We give conditions on the m_i which
guarantee that the ideal of X in P(H^0(X,L)) is generated by quadrics and the
first p syzygies are linear. This yields new results on the syzygies of toric
varieties and the normality of polytopes.Comment: improved exposition and corrected typo
Completions of Z/(p)-Tate cohomology of periodic spectra
We construct splittings of some completions of the Z/(p)-Tate cohomology of
E(n) and some related spectra. In particular, we split (a completion of) tE(n)
as a (completion of) a wedge of E(n-1)'s as a spectrum, where t is shorthand
for the fixed points of the Z/(p)-Tate cohomology spectrum (ie Mahowald's
inverse limit of P_{-k} smash SE(n)). We also give a multiplicative splitting
of tE(n) after a suitable base extension.Comment: 30 pages. Published copy, also available at
http://www.maths.warwick.ac.uk/gt/GTVol2/paper8.abs.htm
Symplectic and Semiclassical Aspects of the Schl\"afli Identity
The Schl\"afli identity, which is important in Regge calculus and loop
quantum gravity, is examined from a symplectic and semiclassical standpoint in
the special case of flat, 3-dimensional space. In this case a proof is given,
based on symplectic geometry. A series of symplectic and Lagrangian manifolds
related to the Schl\"afli identity, including several versions of a Lagrangian
manifold of tetrahedra, are discussed. Semiclassical interpretations of the
various steps are provided. Possible generalizations to 3-dimensional spaces of
constant (nonzero) curvature, involving Poisson-Lie groups and q-deformed spin
networks, are discussed.Comment: 40 pages, 8 figure
A condition-specific codon optimization approach for improved heterologous gene expression in Saccharomyces cerevisiae
All authors are with the Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, USA -- Hal S. Alper is with the Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712, USA
-- Amanda M. Lanza Current Address: Bristol-Myers Squibb, Biologics Development, 35 South Street, Hopkinton, MA 01748, USABackground: Heterologous gene expression is an important tool for synthetic biology that enables metabolic engineering and the production of non-natural biologics in a variety of host organisms. The translational efficiency of heterologous genes can often be improved by optimizing synonymous codon usage to better match the host organism. However, traditional approaches for optimization neglect to take into account many factors known to influence synonymous codon distributions. Results: Here we define an alternative approach for codon optimization that utilizes systems level information and codon context for the condition under which heterologous genes are being expressed. Furthermore, we utilize a probabilistic algorithm to generate multiple variants of a given gene. We demonstrate improved translational efficiency using this condition-specific codon optimization approach with two heterologous genes, the fluorescent protein-encoding eGFP and the catechol 1,2-dioxygenase gene CatA, expressed in S. cerevisiae. For the latter case, optimization for stationary phase production resulted in nearly 2.9-fold improvements over commercial gene optimization algorithms. Conclusions: Codon optimization is now often a standard tool for protein expression, and while a variety of tools and approaches have been developed, they do not guarantee improved performance for all hosts of applications. Here, we suggest an alternative method for condition-specific codon optimization and demonstrate its utility in Saccharomyces cerevisiae as a proof of concept. However, this technique should be applicable to any organism for which gene expression data can be generated and is thus of potential interest for a variety of applications in metabolic and cellular engineering.Chemical EngineeringInstitute for Cellular and Molecular [email protected]
Quasi-reorganizations : a survey of quasi-reorganizations disclosed in corporate annual reports to shareholders; Financial report survey, 39
https://egrove.olemiss.edu/aicpa_news/1199/thumbnail.jp
Illustrations of departures from the new standard auditor\u27s report on financial statements of business enterprises : a survey of the application of SAS no. 58; Financial report survey, 41
https://egrove.olemiss.edu/aicpa_news/1202/thumbnail.jp
Illustrations of cash-flow financial statements : a survey of the application of FASB statement no. 95; Financial report survey, 38
https://egrove.olemiss.edu/aicpa_news/1198/thumbnail.jp
Illustrations of the presentation of financial information about consolidated nonhomogenous subsidiaries; Financial report survey, 40
https://egrove.olemiss.edu/aicpa_news/1201/thumbnail.jp
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