42 research outputs found
A New Concept for Direct Imaging and Spectral Characterization of Exoplanets in Multi-planet Systems
We present a novel method for direct detection and characterization of
exoplanets from space. This method uses four collecting telescopes, combined
with phase chopping and a spectrometer, with observations on only a few
baselines rather than on a continuously rotated baseline. Focusing on the
contiguous wavelength spectra of typical exoplanets, the (u, v) plane can be
simultaneously and uniformly filled by recording the spectrally resolved
signal. This concept allows us to perfectly remove speckles from reconstructed
images. For a target comprising a star and multiple planets, observations on
three baselines are sufficient to extract the position and spectrum of each
planet. Our simulations show that this new method allows us to detect an analog
Earth around a Sun-like star at 10 pc and to acquire its spectrum over the
wavelength range from 8 to 19 {\mu}m with a high spectral resolution of 100.
This method allows us to fully characterize an analog Earth and to similarly
characterize each planet in multi-planet systems.Comment: 10 pages, 12 figure
Physical fitness components associated with performance in a multiple-sprint test.
PURPOSE: The 5-m repeat-sprint test (5-m RST) measures resistance to fatigue after repeated bouts of short-duration, high-intensity activity. This study determined the components of fitness associated with performance in 5-m RSTs. METHODS: Speed (10-m and 40-m sprints), strength (bench press), agility, strength endurance (pull-ups and push-ups), and aerobic power (20-m shuttle-run test) were measured in male provincial- or national-level rugby (n = 110), hockey (n = 59), and soccer (n = 55) players. RESULTS: Subjects with either high (HI) or low (LO) resistance to fatigue in the 5-m RST differed in body mass (76.9 +/- 11.6 kg vs 102.1 +/- 18.9 kg, HI vs LO, respectively, P < .001), agility (14.55 +/- 0.41 seconds vs 15.56 +/- 0.30 seconds, P < .001), bench press (86 +/- 20 kg vs 114 +/- 33 kg, P = .03), pull-ups (13 +/- 4 vs 8 +/- 5, P = .02), push-ups (56 +/- 12 vs 39 +/- 13, P = .002), and 20-m shuttle-run test (20-m SRT; 133 +/- 11 vs 87 +/- 12 shuttles, P < .001). Body mass, strength, and aerobic power were the best predictors of 5-m RST performance: 5-m RST = -1.274(mass) + 0.756(1RM bench press) + 2.053(number of 20-m SRT shuttles) + 549.409 (R2 = .66). CONCLUSIONS: Performance in the 5-m RST is predicted best by a combination of factors including body mass, strength, and aerobic ability, rather than by any single component of fitness
Metodi di regressione non parametrica additiva e il caso "Projection Pursuit Regression"
This article presents a review of recent non parametric additive regression techniques that are appropriate for high dimensional data sets. These methods are related by the fact that they all use some type of additive approximation to describe the underlying regression model. The estimation of the regression function is obtained iteratively through backfitting procedures and the use of smoothers. The second part illustrate the Projection Pursuit Regression method by applying it to various data sets. Sample reuse techniques like bootstrap are used in order to study the particular problem of inference
Errore di predizione e selezione di modelli in Projection Pursuit Regression
Projection Pursuit Regression is a method for non parametric regression dealing with smoothed approximation of the response surface. For this approach we develop the problem of model selection. The suggested criteria of choice are derived and studied using sample use techniques like bootstrap and cross-validation