The Role of Primordial Kicks on Black Hole Merger Rates

Primordial stars are likely to be very massive \geq30\Msun, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range 10^{6}-10^{10}\Ms. Such early black holes, at redshifts z\gtsim10, could be the seed black holes for the many supermassive black holes found in galaxies in the local universe. If they exist, their mergers with nearby supermassive black holes may be a prime signal for long wavelength gravitational wave detectors. We simulate formation of black holes in the center of high redshift dark matter halos and explore implications of initial natal kick velocities conjectured by some formation models. The central concentration of early black holes in present day galaxies is reduced if they are born even with moderate kicks of tens of km/s. The modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the lower mass black holes as compared to those still embedded in their parent halos. Therefore, merger rates may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N--body simulations we quantify the role of natal kicks of black holes formed from massive metal free stars on their merger rates with supermassive black holes in present day galaxies. Our results also apply to black holes ejected by the gravitational slingshot mechanism.Comment: 12 pages, 9 figure

Bohr's inequality revisited

We survey several significant results on the Bohr inequality and presented its generalizations in some new approaches. These are some Bohr type inequalities of Hilbert space operators related to the matrix order and the Jensen inequality. An eigenvalue extension of Bohr's inequality is discussed as well.Comment: 13 pages, to appear in a Springer volume edited by P. Pardalos, H.M. Srivastava, and P. Georgie

LISA Observations of Supermassive Black Hole Growth

Based on a high resolution cosmological n-body simulation, we track the hierarchical growth of black holes in galaxy clusters from z=20 to z=0. We present a census of black holes as function of redshift and will determine their mass assembly history under a variety of assumptions regarding the importance of gas accretion in black hole growth, from early supercritical Eddington accretion to gas-poor hierarchical assembly. Following a galaxy merger, black holes are expected to form, inspiral and merge after strongly radiating energy via gravitational waves. For each binary black hole inspiral and merger, we determine the expected gravitational wave signal for the Laser Interferometer Space Antenna (LISA), and calculate the LISA event rate as a function of time. We will calculate the black hole mass assembly history for several black hole growth scenerios, so that we can explore tests to characterize each model observationally. In particular, we will study how well LISA observations will be able to distinguish between these very different assembly scenarios.Comment: 5 pages, 11 figures, proceedings, Sixth International LISA Symposium, June 19-23, 2006 Goddard Space Flight Center Greenbelt, Marylan

Risk reality vs risk perception

Here we explore new tools to improve risk communication within built infrastructure procurement by considering quantitative engineering risk and perceived risk associated with groups of stakeholders. In particular, the perceived risk is assumed to be dependent on motivational values that individuals identify with. The motivational values are evaluated using 40 questions Swartz Portrait Value Questionnaires. Ten hazards are considered in a survey to identify two dimensions, fear and unknown for a specific group of stakeholders. From the outcomes, it was identified that using a hybrid approach to establish the motivational values and risk perceptions for the stakeholder group risk communication could be improved. Furthermore, the outcomes could be used to target information to stakeholders or intervene to ensure that infrastructure performs according to expectation. As a result, it could become possible to revise what are currently inconsistent acceptable risk levels that have been embedded in regulatory documentation

Risk perception vs. risk reality

Here we explore the feasibility of a rationalized approach to risk within construction procurement by considering explicit engineering risk and perceived risk that selective group of stakeholders share. In particular, the perceived risk is assumed to be dependent on motivational values that individuals identify with. The motivational values are evaluated using 40 questions Swartz Portrait Value Questionnaires. 10 selected hazards are considered in a survey to identify measure of fear and unknown that stakeholders recognize and data analysed. From the outcomes it was identified that by using the alternative approach to establish risk perception the priorities for the stakeholder group in terms of risk can be recognized. Furthermore, the outcomes could be used to target information to stakeholders or intervene to ensure that infrastructure performs according to expectation. As a result, it could become possible to revise what are currently inconsistent acceptable risk levels that have been embedded in active regulatory documentation

The role of translation in undergraduate medical English instruction

For most of its history of undergraduate medical English instruction at Belgrade University, translation was a major part of teaching and assessment. Educational reforms in the early 21st century resulted in a shift towards content-based instruction with the focus on reading comprehension and less translation. The paper analyses the new role of translation in the reformed Serbian curriculum. A brief history of Medical English instruction is outlined. The role of lexicon and the level of discourse within the teaching of English translation in the Serbian curriculum are explored. Some suggestions for the improvement of medical English translation in the Serbian curriculum are offered. It has been shown that translation is a valuable skill to be mastered. Translation exercises allow instructors to recognize language-related comprehension problems. Furthermore, teaching translation is important in that future medical professionals are able to recognize different medical genres and structural differences between English and Serbian

The Law of Treasure in England and Scotland

This article explores the development of treasure law in England and Scotland, tracing its evolution since the time of Edward the Confessor to contemporary legislation and recent revisions. Literature on the subject is not extensive and treasure law has, at times, been ridiculed; as such, this article seeks to properly chronicle the development of this unique and intriguing area of both historic and contemporary law in England and Scotland