44,182 research outputs found
The Auslander-Gorenstein property for Z-algebras
We provide a framework for part of the homological theory of Z-algebras and
their generalizations, directed towards analogues of the Auslander-Gorenstein
condition and the associated double Ext spectral sequence that are useful for
enveloping algebras of Lie algebras and related rings. As an application, we
prove the equidimensionality of the characteristic variety of an irreducible
representation of the Z-algebra, and for related representations over quantum
symplectic resolutions. In the special case of Cherednik algebras of type A,
this answers a question raised by the authors.Comment: 31 page
Differential operators and Cherednik algebras
We establish a link between two geometric approaches to the representation
theory of rational Cherednik algebras of type A: one based on a noncommutative
Proj construction, used in [GS]; the other involving quantum hamiltonian
reduction of an algebra of differential operators, used in [GG].
In the present paper, we combine these two points of view by showing that the
process of hamiltonian reduction intertwines a naturally defined geometric
twist functor on D-modules with the shift functor for the Cherednik algebra.
That enables us to give a direct and relatively short proof of the key result,
[GS, Theorem 1.4] without recourse to Haiman's deep results on the n! theorem.
We also show that the characteristic cycles defined independently in these two
approaches are equal, thereby confirming a conjecture from [GG].Comment: 37 p
Institutional and environmental problems in geothermal resource development
A number of regulatory and institutional impediments to the development of geothermal energy exist. None of these seem likely to prevent the development of this energy source, but in the aggregate they will pace its growth as certainly as the technological issues. The issues are associated with the encouragement of exploration and development, assuring a market for geothermal steam or hot water, and accomplishing the required research and development in a timely manner. The development of geothermal energy in the United States at a high level is apt to cause both favorable and unfavorable, though manageable, impacts in eight major areas, which are discussed
Diversity in Retirement Wealth Accumulation
Examines household wealth by source, such as Social Security, home equity, savings, and defined benefit pensions; how their savings build up with age; and how total wealth accumulations vary by income, education, and race/ethnicity. Explores implications
Will Employers Want Aging Boomers?
Explores the status quo of older workers; why baby boomers are likely to work longer; and how changes in needed skills, the characteristics of older workers, and labor force growth will affect demand for older workers. Includes policy recommendations
Cytomegalovirus infection of the upper gastrointestinal tract following liver transplantation—incidence, location, and severity in cyclosporine- and FK506-treated patients
One hundred and forty randomly selected liver transplant recipients were studied before and after primary orthotopic liver transplantation for the presence or absence of CMV enteritis. Following OLTx, 65 patients were treated with cyclosporine A and 75 were treated with FK506. The two groups were similar with regard to the incidence, location, and outcome of their upper gastrointestinal CMV infection. Prior to OLTx, only one patient had evidence of enteric CMV infection. The incidence of CMV enteritis post-OLTx was 27.7% in the CsA-treated group and 20% in the FK-treated group. During the first posttransplant month, no patient in the FK-treated group developed CMV enteritis, compared with 11.5% of the patients who were treated with CsA (P<0.05). Gastric CMV was found in over 80% of those positive for any organ in either group. In addition to CMV infection of the upper gastrointestinal tract, clinically evident CMV disease involved more nonenteric organs in the CsA-treated group than in the FK-treated group. In the CsA-treated group, CMV-negative patients had a statistically higher 1-year survival rate (100%) than CMV-positive patients (77.8%) (P<0.05). In the FK-treated group, no difference in survival was observed between CMV-positive or CMV-negative cases at 1 year. Of the patients on CsA, 20% received OKT3 for persistent rejection, as compared with 13% in the FK-treated group. The patients receiving both CsA and OKT3 had a higher rate of upper gastrointestinal CMV infection than did FK-treated patients who also received OKT3 therapy (38.5% versus 20%, respectively). Based upon these data, it can be concluded that (1) patients receiving FK have a lower incidence of enteric CMV infection; (2) following OLTx, upper gastrointestinal CMV infection presents later in FK-treated patients; (3) the stomach is the most frequently involved organ in the UGIT; (4) FK-treated liver recipients have less severe enteric CMV infection than do CsA-treated patients; (5) enteric CMV is not a major cause of mortality in liver trans lant recipients; and (6) in patients receiving FK, those who require OKT3 therapy do not appear to be at a greater risk for the development of CMV enteritis than those who do not. © 1992 by Williams & Wilkins
The Mod-2 wind turbine development project
A major phase of the Federal Wind Energy Program, the Mod-2 wind turbine, a second-generation machine developed by the Boeing Engineering and Construction Co. for the U.S. Department of Energy and the Lewis Research Center of the National Aeronautics and Space Administration, is described. The Mod-2 is a large (2.5-MW power rating) horizontal-axis wind turbine designed for the generation of electrical power on utility networks. Three machines were built and are located in a cluster at Goodnoe Hills, Washington. All technical aspects of the project are described: design approach, significant innovation features, the mechanical system, the electrical power system, the control system, and the safety system
Enhanced Molecular Orientation Induced by Molecular Anti-Alignment
We explore the role of laser induced anti-alignment in enhancing molecular
orientation. A field-free enhanced orientation via anti-alignment scheme is
presented, which combines a linearly polarized femtosecond laser pulse with a
half-cycle pulse. The laser pulse induces transient anti-alignment in the plane
orthogonal to the field polarization, while the half-cycle pulse leads to the
orientation. We identify two qualitatively different enhancement mechanisms
depending on the pulse order, and optimize their effects using classical and
quantum models both at zero and non-zero temperature
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