1,304 research outputs found
Alien Registration- Grass, Daniel G. (Mars Hill, Aroostook County)
https://digitalmaine.com/alien_docs/33909/thumbnail.jp
On five-dimensional non-extremal charged black holes and FRW cosmology
We consider static non-extremal charged black hole solutions in the context
of N=2 gauged supergravity theories in five dimensions, and we show that they
satisfy first-order flow equations. Then we analyze the motion of the dual
brane in these black hole backgrounds. We express the entropy in terms of a
Cardy-Verlinde-type formula, and we show that the equations describing the FRW
cosmology on the brane have a form that is similar to the equations for the
entropy and for the Casimir energy on the brane. We also briefly comment on the
inclusion of a Gauss-Bonnet term in the analysis.Comment: 27 pages,5 figures, references adde
On Subextensive Corrections to Fluid Dynamics from Gravity
We use the fluid-gravity correspondence to compute subextensive corrections,
proportional to the shear tensor, to the energy-momentum tensor of fluids on
three-spheres. The dual configurations we consider are charged black hole
solutions of N = 2 gauged supergravity theories in five dimensions.Comment: 26 pages, LaTeX, added comment
EOS: A project to investigate the design and construction of real-time distributed embedded operating systems
The EOS project is investigating the design and construction of a family of real-time distributed embedded operating systems for reliable, distributed aerospace applications. Using the real-time programming techniques developed in co-operation with NASA in earlier research, the project staff is building a kernel for a multiple processor networked system. The first six months of the grant included a study of scheduling in an object-oriented system, the design philosophy of the kernel, and the architectural overview of the operating system. In this report, the operating system and kernel concepts are described. An environment for the experiments has been built and several of the key concepts of the system have been prototyped. The kernel and operating system is intended to support future experimental studies in multiprocessing, load-balancing, routing, software fault-tolerance, distributed data base design, and real-time processing
The mathematics of ageing:
Age is a crucial variable in social sciences and particularly in population dynamics. In this paper, we link methods from formal demography and Operations Research to investigate age-structured models to study the greying of academia. As scientific productivity is usually found to decrease at advanced ages, there was a vivid discussion on the ageing among tenured professors and faculty staff of universities. We investigate population ageing in academia from two perspectives. First, we propose a two-state optimal control model to explain the substantial variations of scientific production over the life cycle of researchers. We identify conditions under which typical hump-shaped age-specific patterns of scientific production turn out to be optimal for individual researchers. The second part of the paper deals with the dynamics of the age structure of scientific institutions. Similar to the university professors, many European learned societies experienced a rapid ageing of their member population, where they face the dilemma that keeping young, i.e. electing young entrants, has the drawback of reducing the replacement rate of members. It turns out that electing a mix of young and old members delivers the optimal solution of the problem, i.e. guaranteeing a young age structure, while ensuring a high recruitment rate
On the Matthew effect in research careers: Abnormality on the boundary
The observation that a socioeconomic agent with a high reputation gets a disproportionately higher recognition for the same work than an agent with lower reputation is typical in career development and wealth. This phenomenon, which is known as Matthew effect in the literature, leads to an increasing inequality over time. The present paper employs an optimal control model to study the implications of the Matthew effect on the optimal efforts of a scientist into reputation.
The solution of the model exhibits, for suffiently low effort costs, a new type of unstable equilibrium at which effort is at its upper bound. This equilibrium, which we denote as Stalling Equilibrium, serves as a threshold level separating success and failure in academia. In addition we show that at the Stalling Equilibrium the solution can be abnormal. We provide a clear economic interpretation for this solution characteristic
On the Matthew effect on Individual Investments into Skills in Arts, Sports and Science
The paper describes the process of capital accumulation subject to the following characteristics: (i) convex returns to (human) capital; (ii) the need to self _nance the investment. This set up is applicable to explain some peculiarities in arts, sports and science, inter alia, the \Matthew effect" coined in Merton (1968) to explain why prominent researchers get disproportional credit for their work. The potential young artist's (or sportsman's or even scientist's) optimal strategies include quitting, or continuing and even expanding one's human capital in a profession. Both outcomes are separated by a threshold level in human capital. In addition, it can be optimal to stay in business although consumption falls and stays at the subsistence level (we call this outcome a \Sisyphus point")
On the importance of hydrodynamic interactions in polyelectrolyte electrophoresis
The effect of hydrodynamic interactions on the free-solution electrophoresis
of polyelectrolytes is investigated with coarse-grained molecular dynamics
simulations. By comparing the results to simulations with switched-off
hydrodynamic interactions, we demonstrate their importance in modelling the
experimentally observed behaviour. In order to quantify the hydrodynamic
interactions between the polyelectrolyte and the solution, we present a novel
way to estimate its effective charge. We obtain an effective friction that is
different from the hydrodynamic friction obtained from diffusion measurements.
This effective friction is used to explain the constant electrophoretic
mobility for longer chains. To further emphasize the importance of hydrodynamic
interactions, we apply the model to end-labeled free-solution electrophoresis.Comment: 15 pages, 7 figures; accepted for publication in J. Phys.: Condens.
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