An Uplifting Discussion of T-Duality

It is well known that string theory has a T-duality symmetry relating circle compactifications of large and small radius. This symmetry plays a foundational role in string theory. We note here that while T-duality is order two acting on the moduli space of compactifications, it is order four in its action on the conformal field theory state space. More generally, involutions in the Weyl group $W(G)$ which act at points of enhanced $G$ symmetry have canonical lifts to order four elements of $G$, a phenomenon first investigated by J. Tits in the mathematical literature on Lie groups and generalized here to conformal field theory. This simple fact has a number of interesting consequences. One consequence is a reevaluation of a mod two condition appearing in asymmetric orbifold constructions. We also briefly discuss the implications for the idea that T-duality and its generalizations should be thought of as discrete gauge symmetries in spacetime.Comment: 47 pages, claims regarding $Z_4$ valued cocycles remove

LIGO vacuum system study

A laser interferometer gravitational wave observatory (LIGO) is being developed with sensitivities which will have a high probability of detecting gravitational waves from astrophysical sources. A major component of LIGO is a total of 16 km of 1.2 m (48 inch) diameter tube at a pressure of less than 10 to the minus 8th power torr. It will be of 304L stainless steel procured directly from the steel mills with the initial hydrogen content specially reduced. Projections of the outgassing rates of hydrogen and of water vapor as a function of time are given and the uncertainties discussed. Based on these, a preliminary analysis of the vacuum system is presented

Loss underreporting and the auditing role of bank exams

Using a unique set of banking data containing both originally reported and subsequently revised financial variables, we study the incidence of adverse revisions to accounting statements. As might be expected, our findings indicate banks are more likely to underreport financial losses when their financial performance is substandard. In addition, we provide evidence that supervisory exams have an important role in uncovering financial problems and ensuring bank accounting statements reflect them. Specifically, our estimations point to a significant auditing effect, through which exams can lead to a restatement of financial results to reflect a greater degree of financial difficulty than originally reported. Interestingly, this auditing role of exams is evident not only for institutions previously identified as supervisory concerns, but also at highly rated banks, where financial problems are only just emerging. Because a banking downturn would increase not only the number of problem institutions requiring additional supervisory attention, but also the incidence of loss underreporting at highly rated banks, our findings stress the value of efforts to maintain or bolster the supervisory system's capacity to expand exam activity quickly and substantially.Banks and banking - Accounting

Landscape Evolution of Titan

Titan may have acquired its massive atmosphere relatively recently in solar system history. The warming sun may have been key to generating Titan's atmosphere over time, starting from a thin atmosphere with condensed surface volatiles like Triton, with increased luminosity releasing methane, and then large amounts of nitrogen (perhaps suddenly), into the atmosphere. This thick atmosphere, initially with much more methane than at present, resulted in global fluvial erosion that has over time retreated towards the poles with the removal of methane from the atmosphere. Basement rock, as manifested by bright, rough, ridges, scarps, crenulated blocks, or aligned massifs, mostly appears within 30 degrees of the equator. This landscape was intensely eroded by fluvial processes as evidenced by numerous valley systems, fan-like depositional features and regularly-spaced ridges (crenulated terrain). Much of this bedrock landscape, however, is mantled by dunes, suggesting that fluvial erosion no longer dominates in equatorial regions. High midlatitude regions on Titan exhibit dissected sedimentary plains at a number of localities, suggesting deposition (perhaps by sediment eroded from equatorial regions) followed by erosion. The polar regions are mainly dominated by deposits of fluvial and lacustrine sediment. Fluvial processes are active in polar areas as evidenced by alkane lakes and occasional cloud cover

Stitch: A Release Management Application

The Stitch web application is a custom tool for use by the Release Management team at Amway to plan and track software releases and infrastructure projects. There are many systems used at Amway to track feature development and infrastructure changes across applications. The goal of this application is to “stitch” all of the disparate data into one system allowing our release team a common interface into all changes associated with a release. In addition, a calendar view allows for visibility into when and where events are scheduled to occur, providing an opportunity to detect conflicts. Stitch was developed using the .NET MVC 4 framework, separating business logic, data, and presentation elements, with code stored in a Git version control repository and tracked in the cloud using Microsoft’s Visual Studio Online

Comparison of ESN, urea, and aqua ammonia as sources of nitrogen for corn production in Iowa

Three nitrogen response studies were conducted in Iowa to compare the effect of a controlled release fertilizer, ESN, to urea and aqua ammonia (AA), on corn grain yields, biomass yields, and soil nitrate (NO3 --N) and ammonium (NH4+-N) concentrations. Experiments were conducted at two sites from 2003 through 2007 for the spring-applied ESN/urea study, two sites from 2006 through 2007 for the fall and spring-applied ESN/AA study, and one site from 2006 through 2007 for the spring applied ESN/AA study. N rates in the studies were 0-202 kg ha-1 in 34 kg N ha-1 increments in the ESN/urea study and 0-202 kg N ha-1 in 67 kg N ha-1 increments in the fall and spring-applied ESN/AA studies. Four of nine site-years in the ESN/urea study had significantly higher corn grain yields due to ESN. One of four site-years in the fall and spring-applied study had higher grain yields to either fall or spring application of ESN. Neither year of the spring-applied ESN/AA study had significantly higher grain yields due to ESN. Biomass yields, the above ground portion of the plant minus the ear, were also collected at physiological maturity. None of the nine site-years in the ESN/urea study had a positive response to ESN. One of the four site-years in the fall and spring-applied ESN/AA study had a positive response to spring-applied ESN. Neither year of the spring-applied ESN/AA study had a positive response to ESN. Soil samples were taken to measure NH4+-N and NO3--N concentrations at the V-6, V-15 growth stages, and also post-harvest at a depth of 0-30 cm. A 31-60 cm soil sample was also taken at post harvest. Throughout all of the studies, ESN treatments usually had higher concentrations of soil NH4+-N and NO3--N. Higher concentrations of residual N left in the soil after harvest can be subject to loss overwinter