Euler solutions using an implicit multigrid technique

A coarse-grid correction algorithm has been implemented into an implicit upwind Euler solver and tested for transonic airfoil problems. The Euler solver uses split-flux formulation and penta-diagonal scalar equations, respectively, for the explicit and implicit operators. The multigrid sequence starts at the fine grid level, then steps down to each coarse grid level to smooth error components using implicit operators. Estimate of residuals can be obtained by two approaches, which differ in the level where the residuals are collected. Both approaches will lead to a work reduction factor of 12 for a Mach 0.75 flow at 2 degrees incidence on a 65x26 grid. The work reduction factor is found to increase proportional to the number of grid levels

On the limits of measuring the bulge and disk properties of local and high-redshift massive galaxies

A considerable fraction of the massive quiescent galaxies at \emph{z} $\approx$ 2, which are known to be much more compact than galaxies of comparable mass today, appear to have a disk. How well can we measure the bulge and disk properties of these systems? We simulate two-component model galaxies in order to systematically quantify the effects of non-homology in structures and the methods employed. We employ empirical scaling relations to produce realistic-looking local galaxies with a uniform and wide range of bulge-to-total ratios ($B/T$), and then rescale them to mimic the signal-to-noise ratios and sizes of observed galaxies at \emph{z} $\approx$ 2. This provides the most complete set of simulations to date for which we can examine the robustness of two-component decomposition of compact disk galaxies at different $B/T$. We confirm that the size of these massive, compact galaxies can be measured robustly using a single S\'{e}rsic fit. We can measure $B/T$ accurately without imposing any constraints on the light profile shape of the bulge, but, due to the small angular sizes of bulges at high redshift, their detailed properties can only be recovered for galaxies with $B/T$ \gax\ 0.2. The disk component, by contrast, can be measured with little difficulty

Chinese approaches to institutionalizing regional multilateralism

Over the last few years, China has promoted all kinds of regional and sub-regional cooperation in Asia. However, the extent of China’s drive for institutionalization of cooperative regional multilateral processes is limited by two realist considerations: I) Distribution of power among the forum participants, and whether the major players are well-disposed towards China or not so and II) the importance of the issues that the specific forum is set up to deal with, particularly to the political, economic or security interests of China, but also that of other participating states. China has successfully pushed for a high degree of institutionalization with the Shanghai Cooperation Organization (SCO) because the only other major participant (Russia) is a friend, and members have a salient accord in pursuing the aims of anti-terrorism and trade promotion. The Six-Party Talks (6PT) is minimally institutionalized because, although the issue of nuclear disarmament of North Korea is important to China, there are many heavy players with their own agenda in the forum (U.S., Japan, and Russia), North Korea itself is a maverick, and the participants have yet to take concrete steps in resolving many issues pertaining to North Korea giving up its nuclear weapons program. The semi-institutionalized character of the ASEAN+3 reflects the consultative nature of the forum that leaders of the Association of Southeast Asian Nations (ASEAN) and China, Japan and South Korea have decided upon, and competition for influence between China and Japan. To increase cooperation with ASEAN without the presence of foreign powers, China has worked towards institutionalizing a separate China-ASEAN axis within the rubric of ASEAN+3

Redshift Evolution In Black Hole-Bulge Relations: Testing C IV-Based Black Hole Masses

We re-examine claims for redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole (BH) mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained with Triplespec at Apache Point Observatory. In support of previous work, we find a large scatter between Balmer and UV line widths, both Mg II lambda lambda 2796, 2803 and CIV lambda lambda 1548, 1550. There is tentative evidence that C III]lambda 1909, despite being a blend of multiple transitions, may correlate well with Mg II, although a larger sample is needed for a real calibration. Most importantly, we find no systematic changes in the estimated BH masses for the lensed sample based on Balmer lines, providing additional support to the interpretation that black holes were overly massive compared to their host galaxies at high redshift.NASA Hubble Fellowship HF-01196NASA NAS 5-26555Astronom

Textbook Readability and Student Performance in Online Introductory Corporate Finance Classes

This paper examines whether the choice of a more readable textbook can improve student performance in online introductory corporate finance classes. The ordinary least squares regression model is employed to analyze a sample of 206 students during the period from 2008 to 2012. The results of this study show that the student’s age, student’s major, student bachelor’s degree obtained, and number of hours a student works are significant determinants of student performance. In contrast to my expectation, I find that the choice of a more readable textbook does not improve student performance

Hybrid Versus Face-to-Face: Evidence From Introductory Corporate Finance Classes

This study examines whether there is a difference in student performance between hybrid and face-to-face introductory corporate finance classes. The ordinary least squares regression model is employed to analyze a sample of 194 students at a four-year state university in the Appalachian region. The results show that students who receive in-class lectures and take online exams in hybrid classes perform better than those who take in-class exams in face-to-face classes, but is not statistically significant. The implication is that instructors for face-to-face classes can consider substituting in-class exams with online exams because neither do online exams change the rigor of the course nor harm student performance. The results also show that student’s major is a significant determinant of student performance