20,449 research outputs found
Properties of Microlensing Central Perturbations by Planets in Binary Stellar Systems under the Strong Finite-Source Effect
We investigate high-magnification events caused by planets in wide binary
stellar systems under the strong finite-source effect, where the planet orbits
one of the companions. From this, we find that the pattern of central
perturbations in triple lens systems commonly appears as a combination of
individual characteristic patterns of planetary and binary lens systems in a
certain range where the sizes of the caustics induced by a planet and a binary
companion are comparable, and the range changes with the mass ratio of the
planet to the planet-hosting star. Specially, we find that because of this
central perturbation pattern, the characteristic feature of high-magnification
events caused by the triple lens systems appears in the residual from the
single-lensing light curve despite the strong finite-source effect, and it is
discriminated from those of the planetary and binary lensing events and thus
can be used for the identification of the existence of both planet and binary
companion. This characteristic feature is a simultaneous appearance of two
features. First, double negative-spike and single positive-spike features
caused by the binary companion appear together in the residual, where the
double negative spike occurs at both moments when the source enters and exits
the caustic center and the single positive spike occurs at the moment just
before the source enters into or just after the source exits from the caustic
center. Second, the magnification excess before or after the single
positive-spike feature is positive due to the planet, and the positive excess
has a remarkable increasing or decreasing pattern depending on the source
trajectory.Comment: 12 pages, 3 figures, accepted for publication in Ap
Site Response Analysis Using Forced-Vibration Tests on Hydraulic-Filled Soil Deposit
Forced vibration tests and detailed site characterization were performed at a geotechnical experimental site in Yong-jong Island where Inchon International Airport being constructed. The vibratory motions generated by the combination of hydraulic hammer compaction and dynamic compaction were monitored by 3-component velocity transducers in the down hole array as well as on the ground surface. Spectral analyses of the recorded vibratory motions were performed to evaluate the resonant frequencies of the experimental site. The linear analysis and simplified method were also performed to evaluate the resonant frequencies of the experimental site based on the results of detailed site investigation. The resonant frequencies of the experimental site evaluated by spectral analyses based on forced vibration tests were in good agreement with those of the linear analysis and the simplified method
Effects of Increasing Concentrations of Corn Distiller’s Dried Grains with Solubles on Chemical Composition and Nutrients Content of Egg
Four diets were formulated to contain 0, 17, 35 or 50% corn DDGS. A total of 240 54-week-old single-comb White Leghorn laying hens were assigned to one of four dietary treatments and fed for a 24-week experimental period. Two sets of the experimental diets were formulated and each diet was fed for 12 weeks. Chemical composition and nutritional components in egg yolk were measured. Egg yolk from hens fed DDGS-containing diet tended to have higher fat content and lower protein content. Total polyunsaturated fatty acids were significantly increased by DDGS diet. The contents of choline and cholesterol were initially higher in 50% DDGS treatment group, but were not different in the later period, especially during last 4 weeks. Lutein content increased linearly as DDGS level increased. The results indicated that feeding high level of DDGS can increase the content of lutein and polyunsaturated fatty acids in egg yolk, but may not affect the content of cholesterol or choline
When Are Power Shifts Dangerous?: Military Strategy and Preventive War
This article explains why shifts in the balance of power lead to war in some cases, but not in others. I argue that the declining states military strategy is the key determinant of whether power shifts will result in war or pass peacefully. If the decliner has a maneuver strategy, then war is likely; if it has an attrition strategy, the power shift will pass peacefully. I test the plausibility of my theory and three prominent alternatives by taking a sample of twelve power shifts among great powers over the period 1860-1945 and establishing correlations between the indicators used by all four theories and the incidence in each case of war or peace. This article finds that for the large majority of the examined cases, the decliners military strategy correctly predicts the power shifts political outcom
Americas International Leadership in Transition: From Global Hegemony towards Offshore Leadership
This article aims to help make sense of the change which Americas international leadership has undergone by performing two tasks. One is offering a focused (as opposed to comprehensive) assessment on US international leadership of the post-Cold War period. The appraisal reveals that Washingtons strong will to lead is a mixed blessing for both itself and others: while contributing crucially to global public goods provision, US leadership occasionally exacerbates certain international problems as it overreaches itself (particularly in inland areas such as Iraq and Ukraine). The other task is analyzing an emerging strategy that Washington has been formulating in its effort to adjust to the transforming strategic environment brought forth partly by its excessive will to lead. The key point here is that America is developing an offshore leadership strategy: it aims to remain the most influential (albeit not sole) leader by establishing its sphere of influence firmly over maritime and coastal regions (while trying to avoid inland interventions).This research was supported by a Korea University Grant (K1421291). The author thanks Ronald Pruessen and three anonymous reviewers for their helpful comments
A Planetary lensing feature in caustic-crossing high-magnification microlensing events
Current microlensing follow-up observations focus on high-magnification
events because of the high efficiency of planet detection. However, central
perturbations of high-magnification events caused by a planet can also be
produced by a very close or a very wide binary companion, and the two kinds of
central perturbations are not generally distinguished without time consuming
detailed modeling (a planet-binary degeneracy). Hence, it is important to
resolve the planet-binary degeneracy that occurs in high-magnification events.
In this paper, we investigate caustic-crossing high-magnification events caused
by a planet and a wide binary companion. From this study, we find that because
of the different magnification excess patterns inside the central caustics
induced by the planet and the binary companion, the light curves of the
caustic-crossing planetary-lensing events exhibit a feature that is
discriminated from those of the caustic-crossing binary-lensing events, and the
feature can be used to immediately distinguish between the planetary and binary
companions. The planetary-lensing feature appears in the interpeak region
between the two peaks of the caustic-crossings. The structure of the interpeak
region for the planetary-lensing events is smooth and convex or boxy, whereas
the structure for the binary-lensing events is smooth and concave. We also
investigate the effect of a finite background source star on the
planetary-lensing feature in the caustic-crossing high-magnification events.
From this, we find that the convex-shaped interpeak structure appears in a
certain range that changes with the mass ratio of the planet to the
planet-hosting star.Comment: 14 pages, 4 figures. Accepted for publication in Ap
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