29,005 research outputs found
Identification and evaluation of educational uses and users for the STS. Educational planning for utilization of space shuttle ED-PLUSS
A planning and feasibility study to identify and document a methodology needed to incorporate educational programs into future missions and operations of the space transportation system was conducted. Six tasks were identified and accomplished during the study. The task statements are as follows: (1) potential user identification, (2) a review of space education programs, (3) development of methodology for user involvement, (4) methods to encourage user awareness, (5) compilation of follow-on ideas, and (6) response to NASA questions. Specific recommendations for improving the educational coverage of space activities are provided
Frequency Dependent Specific Heat from Thermal Effusion in Spherical Geometry
We present a novel method of measuring the frequency dependent specific heat
at the glass transition applied to 5-polyphenyl-4-ether. The method employs
thermal waves effusing radially out from the surface of a spherical thermistor
that acts as both a heat generator and thermometer. It is a merit of the method
compared to planar effusion methods that the influence of the mechanical
boundary conditions are analytically known. This implies that it is the
longitudinal rather than the isobaric specific heat that is measured. As
another merit the thermal conductivity and specific heat can be found
independently. The method has highest sensitivity at a frequency where the
thermal diffusion length is comparable to the radius of the heat generator.
This limits in practise the frequency range to 2-3 decades. An account of the
3omega-technique used including higher order terms in the temperature
dependency of the thermistor and in the power generated is furthermore given.Comment: 17 pages, 15 figures, Substantially revised versio
Deconstructed Higgsless Models at LHC: The Top Triangle Moose
We describe a deconstructed Higgsless model in which electroweak symmetry
breaking results largely from a Higgsless mechanism while the top quark mass is
generated by a topcolor mechanism. The top quark mass arises from a Yukawa
coupling to an effective top-Higgs which develops a small vacuum expectation
value. Both the heavy partners of the electoweak gauge bosons and those for the
SM fermions can be light enough to be visible at LHC.Comment: 5 pages, 3 figures; from the Proceedings of the 2010 Rencontres de
Bloi
Inflation expectations and risk premiums in an arbitrage-free model of nominal and real bond yields
Differences between yields on comparable-maturity U.S. Treasury nominal and real debt, the so-called breakeven inflation (BEI) rates, are widely used indicators of inflation expectations. However, better measures of inflation expectations could be obtained by subtracting inflation risk premiums from the BEI rates. We provide such decompositions using an estimated affine arbitrage-free model of the term structure that captures the pricing of both nominal and real Treasury securities. Our empirical results suggest that long-term inflation expectations have been well anchored over the past few years, and inflation risk premiums, although volatile, have been close to zero on average.Inflation (Finance) ; Treasury bonds
The Top Triangle Moose
We introduce a deconstructed model that incorporates both Higgsless and
top-color mechanisms. The model alleviates the typical tension in Higgsless
models between obtaining the correct top quark mass and keeping delta-rho
small. It does so by singling out the top quark mass generation as arising from
a Yukawa coupling to an effective top-Higgs which develops a small vacuum
expectation value, while electroweak symmetry breaking results largely from a
Higgsless mechanism. As a result, the heavy partners of the SM fermions can be
light enough to be seen at the LHC.Comment: To appear in proceedings of SCGT09, Nagoya, Japan. 5 page
The Affine Arbitrage-Free Class of Nelson-Siegel Term Structure Models
We derive the class of arbitrage-free affine dynamic term structure models that approximate the widely-used Nelson-Siegel yield-curve specification. Our theoretical analysis relates this new class of models to the canonical representation of the three-factor arbitrage-free affine model. Our empirical analysis shows that imposing the Nelson-Siegel structure on this canonical representation greatly improves its empirical tractability; furthermore, we find that improvements in predictive performance are achieved from the imposition of absence of arbitrage.arbitrage, Nelson-Siegel, term structure, factor models, forecast accuracy
Educational planning for utilization of space shuttle (ED-PLUSS). Executive summary: Identification and evaluation of educational uses and users for the STS
The development and application of educational programs to improve public awareness of the space shuttle/space lab capabilities are reported. Special efforts were made to: identify the potential user, identify and analyze space education programs, plan methods for user involvement, develop techniques and programs to encourage new users, and compile follow-on ideas
Extracting deflation probability forecasts from Treasury yields
We construct probability forecasts for episodes of price deflation (i.e., a falling price level) using yields on nominal and real U.S. Treasury bonds. The deflation probability forecasts identify two "deflation scares" during the past decade: a mild one following the 2001 recession, and a more serious one starting in late 2008 with the deepening of the financial crisis. The estimated deflation probabilities are generally consistent with those from macroeconomic models and surveys of professional forecasters, but they also provide highfrequency insight into the views of financial market participants. The probabilities can also be used to price the deflation option embedded in real Treasury bonds.Deflation (Finance)
White matter hyperintensities and within-person variability in community-dwelling adults aged 60–64 years
Estimates of white matter hyperintensities (WMH) derived from T2-weighted MRI were investigated in relation to cognitive performance in 469 healthy community-dwelling adults aged 60–64 years. Frontal lobe WMH but not WMH from other brain regions (temporal, parietal, and occipital lobes, anterior and posterior horn, periventricular body) were associated with elevated within-person reaction time (RT) variability (trial to trial fluctuations in RT performance) but not performance on several other cognitive tasks including psychomotor speed, memory, and global cognition. The findings are consistent with the view that elevated within-person variability is related to neurobiological disturbance, and that attentional mechanisms supported by the frontal cortex play a key role in this type of variability
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