We examine the formation of giant elliptical galaxies using their globular cluster (GC) systems as probes of their evolutionary history. The bimodal distributions of GC metallicities in such galaxies are often cited as evidence for the formation of giant elliptical galaxies through mergers involving gas-rich spirals, with the metal-rich GCs forming during the merger process. We explore an alter...

We study the stability of the giant gravitons in the string theory background with NSNS B field. We consider the perturbation of giant gravitons formed by a probe D(8− p) brane in the background generated by D(p− 2)D(p) branes for 2 ≤ p ≤ 5. We use the quadratic approximation to the brane action to find the equations of motion. The vibration modes for ρ , φ and r are coupled, while those of xk’...

Paying off the mortgage, once a widespread rite of passage for homeowners approaching retirement, has become less common in recent years. Concerns are mounting that the increased prevalence of housing debt among older homeowners could compromise financial security in retirement by expanding housing affordability problems, crimping essential nonhousing spending, increasing vulnerability to home ...

conclusions optimal wc values for defining mets were 91.5 cm and 85.5 cm in men and women, respectively. the cut-off values recommended by world organizations are not appropriate for an adult population living in ahvaz city. results the cut-off points of wc, according to a maximum sum of sensitivity plus specificity for detecting at least two components of mets were found to be 91.5 cm and 85.5...

A Chebyshev or Fourier series may be evaluated on the standard collocation grid by the Fast Fourier Transform (FFT). Unfortunately, the FFT does not apply when one needs to sum a spectral series at N points which are spaced irregularly. The cost becomes O(N2) operations instead of the FFT's O(N log N). This sort of "off-grid" interpolation is needed by codes which dynamically readjust the grid ...

The wavelet transform-domain least-mean square (WTDLMS) algorithm uses the self-orthogonalizing technique to improve the convergence performance of LMS. In WTDLMS algorithm, the trade-off between the steady-state error and the convergence rate is obtained by the fixed step-size. In this paper, the WTDLMS adaptive algorithm with variable step-size (VSS) is established. The step-size in each subf...

In design and fabricate drive shafts with high value of fundamental natural frequency that represented high value of critical speed; using composite materials instead of typical metallic materials could provide longer length shafts with lighter weight. In this paper, multi-objective optimization (MOP) of a composite drive shaft is performed considering three conflicting objectives: fundamental ...

We apply the dressing method to a string solution given by a static string wrapped around the equator of a three-sphere and find that the result is the single spike solution recently discussed in the literature. Further application of the method allows the construction of solutions with multiple spikes. In particular we construct the solution describing the scattering of two single spikes and c...

purpose: to determine the accuracy of photorefraction and autorefraction as compared to cycloautorefraction and to detect the repeatability of photorefraction. methods: this diagnostic study included the right eyes of 86 children aged 7‑12 years. refractive status was measured using photorefraction (plusoptix so4, gmbh, nürnberg, germany) and autorefraction (topcon rm800, usa) with and without ...