Enhanced off-center stellar tidal disruptions by supermassive black holes in merging galaxies

Off-center stellar tidal disruption flares have been suggested to be a powerful probe of recoiling supermassive black holes (SMBHs) out of galactic centers due to anisotropic gravitational wave radiations. However, off-center tidal flares can also be produced by SMBHs in merging galaxies. In this paper, we computed the tidal flare rates by dual SMBHs in two merging galaxies before the SMBHs become self-gravitationally bounded. We employ an analytical model to calculate the tidal loss-cone feeding rates for both SMBHs, taking into account two-body relaxation of stars, tidal perturbations by the companion galaxy, and chaotic stellar orbits in triaxial gravitational potential. We show that for typical SMBHs with mass 10^7 M_\sun, the loss-cone feeding rates are enhanced by mergers up to \Gamma ~ 10^{-2} yr^{-1}, about two order of magnitude higher than those by single SMBHs in isolated galaxies and about four orders of magnitude higher than those by recoiling SMBHs. The enhancements are mainly due to tidal perturbations by the companion galaxy. We suggest that off-center tidal flares are overwhelmed by those from merging galaxies, making the identification of recoiling SMBHs challenging. Based on the calculated rates, we estimate the relative contributions of tidal flare events by single, binary, and dual SMBH systems during cosmic time. Our calculations show that the off-center tidal disruption flares by un-bound SMBHs in merging galaxies contribute a fraction comparable to that by single SMBHs in isolated galaxies. We conclude that off-center tidal disruptions are powerful tracers of the merging history of galaxies and SMBHs.Comment: 17 pages, 8 figures; Typos are corrected to match the published version in Ap

Low-complexity Noncoherent Iterative CPM Demodulator for FH Communication

In this paper, we investigate the noncoherent iterative demodulation of coded continuous phase modulation (CPM) in frequency hopped (FH) systems. In this field, one important problem is that the complexity of the optimal demodulator is prohibitive unless the number of symbols per hop duration is very small. To solve this problem, we propose a novel demodulator, which reduces the complexity by applying phase quantization and exploiting the phase rotational invariance property of CPM signals. As shown by computational complexity analysis and numerical results, the proposed demodulator approaches the performance of the optimal demodulator, and provides considerable performance improvement over the existing solutions with the same computational complexity

The apple of China

An equity research involves analyzing a company’s financial information and forecasting it with the intention of making an investment recommendation of either buy or sell its stock. The goal of this paper is to analyze Xiaomi Corporation’s financial information, forecast the company’s value in the future and, though that, make an investment recommendation about whether it is better to buy or sell Xiaomi Corporation’s stock by comparing Xiaomi Corporation’s market stock price with its theoretical target price. For that effect, the DCF valuation method was applied and the investment recommendation was to buy Xiaomi Corporation’s stock

Exploring Health Education Delivered to Patients with Acute Coronary Syndrome and Type 2 Diabetes Mellitus Admitted to a Shanghai Hospital

Introduction Patients with both acute coronary syndrome (ACS) and type 2 diabetes mellitus (T2DM) are the focus of this thesis. Together these conditions represent a substantial burden of illness within Western and now Eastern countries. Patients presenting with multiple conditions are frequently encountered within clinical practice, with often poorer clinical outcomes than those with a single condition. The challenge of delivering health education is substantial when patients experience two or more health conditions. Within China, health education is provided principally during the acute admission period, often for ACS. In this unique cultural setting, there has been little research about the delivery by health professionals of health education to patients with both ACS and T2DM. Aims The aims of this research are to gain an understanding of the current health education delivered by health care professionals and received by patients with ACS and T2DM within Shanghai. In particular the impact of such education on patients’ behavioural change, clinical outcomes, and self-efficacy and self-management was examined. Methods An umbrella systematic review was conducted including 51 eligible reviews (15 for ACS and 36 for T2DM). This was followed by a qualitative study of 15 health professionals’ experience of delivering health education to this patient group (Study 1). Finally, a mixed methods study of delivering health education to this patient group (Study 1). Finally, a mixed methods study of patients, including a cross-sectional survey (n = 160), patient health care record audit of clinical outcomes (n = 160), and two interviews with patients at discharge and at follow-up (n = 21) in the community, was conducted. The study setting was a coronary care unit (CCU) within a major referral hospital within Shanghai, China. Data were collected from July 2016 to March 2017. Perceived health education received was measured using a visual analogue scale (VAS) ranging from 1 (little or no education) to 100 (comprehensive education) in the survey for patients. The survey for patients was followed by a semi-structured interview before discharge and a telephone-based follow-up interview up to four weeks after discharge from hospital. Twenty-one of the 160 patients completed the survey and participated in the two semi-structured interviews

Minorities in Tech: Disparities and Explanations

The world of African Americans and Hispanics in tech is small. This paper attempts to gauge exactly how small and expand on the two predominant explanations of potential disparities as well as potential solutions

Dislocations in Strained-layer Semiconductor Heterostructures.

The reliability of semiconductor devices depends upon the stability of the constituent materials. Strained-layer semiconductor structures contain a layer whose lattice constant differs from the surrounding layers, resulting in a misfit strain. As dislocations are the main failure mechanism in semiconductor lasers, it is essential to establish whether the stability of these structures is affected by the lattice mismatch and the possibility of relaxation by the formation of misfit dislocations. In this thesis, dislocations in strained-layer semiconductor structures are investigated. Relaxation of strained-layer GaAs/InxGa1-xAs/GaAs heterostructures through the formation of misfit dislocations is found to occur in stages. Firstly, generation and elongation of misfit dislocations on threading dislocations during molecular beam epitaxy (MBE) growth have been demonstrated with increasing strained-layer thickness. The onset of this stage has been shown to occur at strained-layer thicknesses below those predicted by the Matthews-Blakeslee (M-B) model. The second stage of relaxation is marked by the formation of a network of 60° misfit dislocations. A third stage of relaxation has been discovered, in which pure edge (i.e. 90°) misfit dislocations are formed in addition to the existing network of 60° misfit dislocations. Different mechanisms are found to be responsible for the three stages of relaxation. The M-B model describes the transformation of threading dislocations to generate 60° misfit dislocations. As this affects individual dislocations, it results in only local relaxation. A separate mechanism, which remains unclear but is not dependent on the interactions of dislocations, dominates the formation of a 60° misfit dislocation network. The edge dislocations responsible for further relaxation of the structures are produced by vacancy-producing jogs. These protrude from pre-existing 60° dislocations and trail edge dislocation pairs as they climb. It is shown here that as-grown structures with strained-layer thicknesses below the theoretical prediction can be relaxed by the formation of a 60° dislocation network during post-growth thermal processing and bending. Thus the first two stages of relaxation are dependent on both the strained-layer thickness during fabrication, and on the temperature and applied stress of as-grown structures. Finally, dislocation motion in strained layer structures has been shown to be slower than that in unstrained structures. Thus the misfit stress acts as an additional resistant force to the displacement of atoms in non-misfit dislocations, even though it drives the formation of misfit dislocations

Holographic thermalization with a chemical potential in Gauss-Bonnet gravity

Holographic thermalization is studied in the framework of Einstein-Maxwell-Gauss-Bonnet gravity. We use the two-point correlation function and expectation value of Wilson loop, which are dual to the renormalized geodesic length and minimal area surface in the bulk, to probe the thermalization. The numeric result shows that larger the Gauss-Bonnet coefficient is, shorter the thermalization time is, and larger the charge is, longer the thermalization time is, which implies that the Gauss-Bonnet coefficient can accelerate the thermalization while the charge has an opposite effect. In addition, we obtain the functions with respect to the thermalization time for both the thermalization probes at a fixed charge and Gauss-Bonnet coefficient, and on the basis of these functions, we obtain the thermalization velocity, which shows that the thermalization process is non-monotonic. At the middle and later periods of the thermalization process, we find that there is a phase transition point, which divides the thermalization into an acceleration phase and a deceleration phase. We also study the effect of the charge and Gauss-Bonnet coefficient on the phase transition point.Comment: 23 pages, many figures,footnote 4 is modified. arXiv admin note: substantial text overlap with arXiv:1305.484