7,458 research outputs found
Financial signal processing: a self calibrating model
Previous work on multifactor term structure models has proposed that the short rate process is a function of some unobserved diffusion process. We consider a model in which the short rate process is a function of a Markov chain which represents the 'state of the world'. This enables us to obtain explicit expressions for the prices of zero-coupon bonds and other securities. Discretizing our model allows the use of signal processing techniques from Hidden Markov Models. This means we can estimate not only the unobserved Markov chain but also the parameters of the model, so the model is self-calibrating. The estimation procedure is tested on a selection of U.S. Treasury bills and bonds.Bonds
Potential markets for a satellite-based mobile communications system
The objective of the study was to define the market needs for improved land mobile communications systems. Within the context of this objective, the following goals were set: (1) characterize the present mobile communications industry; (2) determine the market for an improved system for mobile communications; and (3) define the system requirements as seen from the potential customer's viewpoint. The scope of the study was defined by the following parameters: (1) markets were confined to U.S. and Canada; (2) range of operation generally exceeded 20 miles, but this was not restrictive; (3) the classes of potential users considered included all private sector users, and non-military public sector users; (4) the time span examined was 1975 to 1985; and (5) highly localized users were generally excluded - e.g., taxicabs, and local paging
Cold Collision Frequency Shift of the 1S-2S Transition in Hydrogen
We have observed the cold collision frequency shift of the 1S-2S transition
in trapped spin-polarized atomic hydrogen. We find , where is the sample density. From this
we derive the 1S-2S s-wave triplet scattering length, nm,
which is in fair agreement with a recent calculation. The shift provides a
valuable probe of the distribution of densities in a trapped sample.Comment: Accepted for publication in PRL, 9 pages, 4 PostScript figures,
ReVTeX. Updated connection of our measurement to theoretical wor
Adolescents care but don't feel responsible for farm animal welfare
Adolescents are the next generation of consumers with the potential to raise standards of farm animal welfareâto theirsatisfactionâif their preferences and concerns are translated into accurate market drivers and signals. There are no published data about adolescent views of farm animal welfare to allow meaningful design, implementation, and evaluation of educational strategies to improve consideration ofâand behavior towardâfarm animals. Knowledge of farm animal welfare, as well as beliefs and attitudes about farm animal welfare and behavioral intention relevant to it were determined in a sample of ukadolescents, using a survey incorporating an extended version of the theory of planned behavior and novel assessment tools. Our results indicate that adolescents have only a limited knowledge of welfare problems for farm animals and welfare-relevant product labels. Intentions to identify welfare standards for the animals from whom their food was derived were weak. Although they cared about farm animal welfare and agreed with fundamental principlesâfor example, the provision of space and the absence of pain and sufferingâlike adults they held limited belief in the power and responsibility that they possess through their choices as consumers; responsibility was often shifted to others, such as the government and farmers
Understanding the Role of Relationship Maintenance in Enduring Couple Partnerships in Later Adulthood
Intimate relationships in later adulthood are understudied despite their positive association with health and well-being. This cross-sectional mixed methods study sought to redress this gap by investigating relationship maintenance in later adulthood. Our international sub-sample comprised 1,565 participants aged 55â+âand in an ongoing relationship. Results from hierarchical multiple regression indicated that overall happiness with the relationship had the largest effect size on relationship maintenance, with 53% of the variance explained. Content analyses of open-ended questions identified companionship and laughter as some of the âbest likedâ aspects of the relationship. Housework/cooking and saying âI love youâ were among the behaviors that made participants feel appreciated. Results illustrated the types of maintenance behaviors adults in later adulthood who are in enduring partnerships employ
Age and Waist Circumference Modify Discordance of Body Fat Measurements in Adults with Obesity
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Bias spectroscopy and simultaneous SET charge state detection of Si:P double dots
We report a detailed study of low-temperature (mK) transport properties of a
silicon double-dot system fabricated by phosphorous ion implantation. The
device under study consists of two phosphorous nanoscale islands doped to above
the metal-insulator transition, separated from each other and the source and
drain reservoirs by nominally undoped (intrinsic) silicon tunnel barriers.
Metallic control gates, together with an Al-AlOx single-electron transistor,
were positioned on the substrate surface, capacitively coupled to the buried
dots. The individual double-dot charge states were probed using source-drain
bias spectroscopy combined with non-invasive SET charge sensing. The system was
measured in linear (VSD = 0) and non-linear (VSD 0) regimes allowing
calculations of the relevant capacitances. Simultaneous detection using both
SET sensing and source-drain current measurements was demonstrated, providing a
valuable combination for the analysis of the system. Evolution of the triple
points with applied bias was observed using both charge and current sensing.
Coulomb diamonds, showing the interplay between the Coulomb charging effects of
the two dots, were measured using simultaneous detection and compared with
numerical simulations.Comment: 7 pages, 6 figure
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