8,017 research outputs found
Self-Duality and the KdV Hierarchy
We derive the entire KdV hierarchy as well as the recursion relations from
the self-duality condition on gauge fields in four dimensions.Comment: 7 page
Near infra-red spectroscopy of V838 Monocerotis
Near IR, multi-epoch, spectroscopic and photometric observations of the
enigmatic, eruptive variable V838 Mon in JHK bands are reported. One of the
unusual features is the detection of several strong neutral TiI lines in
emission in the K band. From the strength of these lines, the mass of the
ejected envelope is estimated to be in the range 10e-7 to 10e-5 M(sun). The
spectra also show the strong presence of the first and second overtones of 12CO
bands seen in the K and H bands. The CO bands show a complex evolution. Deep
water bands at 1.4 and 1.9 micron are also seen later in the object's
evolution. Blackbody fits to the JHK photometric data show that V838 Mon has
evolved to temperatures between 2400 - 2600 K by approximately 130 days after
outburst. The spectra at this stage have the general characteristics of a very
cool M giant.Comment: 7 pages, 5 figures, to appear in Astronomy and Astrophysic
Internet Access and Use by Farm Households
The Internet is a strategic technology because it has found application across virtually all sectors of the economy. The Internet has become an everyday part of rural life and is an important new technology in U.S. agriculture. This study uses information collected through the 2004 Agricultural Resource Management Survey (ARMS) to explore the adoption of computers with Internet access and Internet use by farm households. Results from this study suggest that adoption of computers with Internet access is positively related to age and educational level of the operator, off-farm business income, presence of a spouse, and regional location of the farm. Further, large farms and part-owner farms are more likely to adopt computers with Internet access. Internet use for the farm, household, or both is strongly related to the educational level of the operator and spouse, presence of teenagers in the household, farm size, and regional location of the farm.Research and Development/Tech Change/Emerging Technologies,
Policy Reform and Off-farm Labor Supply by Operators in the Delta Region: A
Off-farm employment has been an integral part of the emerging structure of production agriculture in the South. Government farm program payments, farm structure, and strong non-farm economy have important impact on labor allocation, farm and non-farm labor, decision of farm operators. The objective of this investigation was to evaluate the determinants of off-farm labor supply for farm operators in the Delta States. Results show that off-farm work, educational level, presence of teenager, and farm tenure positive and significant impact on ff-farm labor supply by farm operators. On the other hand, farm size, household wealth, decoupled and couple farm program payments, and degree of farm diversification have a negative and significant impact on off-farm labor supply by farm operators. the semiparametreic functional formulation of the farm size and household wealth variables were found to perform better than the linear functional form.Off-farm labor supply, Delta region, Tobit, semiparametric, government farm program payments, education, Farm Management, Labor and Human Capital,
Patching up the monopole potential
It is well known that a vector potential cannot be defined over the whole
surface of a sphere around a magnetic monopole. A recent claim to the contrary
is shown to have problems. It is explained however that a potential of the
proposed type works if two patches are used instead of one. A general
derivation of the Dirac quantization condition attempted with a single patch is
corrected by introducing two patches. Further, the case of more than two
patches using the original Wu-Yang type of potential is discussed in brief.Comment: 6 page
Near-Infrared and Optical Studies of the fast nova V4643 Sgr (Nova Sagittarii 2001)
V4643 Sagittarii or Nova Sagittarii 2001 was discovered in outburst at 7.7
mag. on 2001 February 24. Here, we present near-infrared results of this fast
classical nova obtained in the early decline phase in 2001 March followed by
optical observations about one month later. Subsequently we also present
near-infrared spectra taken later in the nova's evolution, about four months
after the outburst, when V4643 Sgr had entered the coronal phase. The spectra
in the early decline phase are dominated by emission lines of the HI Brackett
series and also the Paschen beta and gamma lines. We study the cause of the
excitation of the the OI line at 1.128 micron and discuss the variation in its
strength with time after outburst. We discuss the role of optical depth effects
on the observed strengths of the hydrogen Brackett and Paschen lines and
discuss possible reasons for the puzzling behavior of the Br gamma line
strength and whether it is correlated with the OI 1.128 micron line behavior.
An optical spectrum is presented which shows that HeII lines are the most
prominent features - after HI - to be seen in early 2001 April. We present and
also discuss spectra taken in 2001 June and August which prominently show
coronal lines of [Si VI] and [Si VII] at 1.9641 micron and 2.4807 micron
respectively.Comment: Accepted in MNRA
Simulating the Effect of Pay Table Standard Deviation on Pulls Per Losing Player at the Single-visit Level
While holding par constant, changes in the standard deviation of the pay table produced an inverse effect on pulls per losing player (PPLP), across six different virtual slot machines. This result establishes the standard deviation of a game as a crucial determinant of a slot player\u27s experience. Three different single-trip scenarios were examined via computer simulation, with 50,000 players engaging each game. For example, virtual players began with 100 units, terminating play at bankruptcy or 200 units. As players focus on the outcome of single visits, understanding the determinants of PPLP (or time on device) will help management engineer desirable customer experiences at the trip level. In part, this can be achieved by altering the product mix to better match the expectations of the clientele. Given the remarkable bankruptcy rate of the trip simulations, proxies for value such as PPLP serve as crucial evaluation standards in the satisfaction process
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