5,972 research outputs found
New aircraft instrument indicates turbulence intensity
System consists of accelerometer, indicator, and necessary electronic circuits for summing and averaging accelerations. Averaging-time feature enables pilot to see large values of accelerations over a short time or smaller accelerations over longer period of time
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The Impact of Industry Collaboration on Academic Research Output: A Dynamic Panel Data Analysis
The aim of this paper is to analyse the impact of university knowledge and technology transfer activities on academic research output. Specifically, we study whether researchers with collaborative links with the private sector publish less than their peers without such links, once controlling for other sources of heterogeneity. We report findings from a longitudinal dataset on researchers from two engineering departments in the UK between 1985 until 2006. Our results indicate that researchers with industrial links publish significantly more than their peers. Academic productivity, though, is higher for low levels of industry involvement as
compared to high levels
Quantum Inhomogeneities in String Cosmology
Within two specific string cosmology scenarios --differing in the way the
pre- and post-big bang phases are joined-- we compute the size and spectral
slope of various types of cosmologically amplified quantum fluctuations that
arise in generic compactifications of heterotic string theory. By further
imposing that these perturbations become the dominant source of energy at the
onset of the radiation era, we obtain physical bounds on the background's
moduli, and discuss the conditions under which both a (quasi-) scale-invariant
spectrum of axionic perturbations and sufficiently large seeds for the galactic
magnetic fields are generated. We also point out a potential problem with
achieving the exit to the radiation era when the string coupling is near its
present value.Comment: 30 pages, RevteX, epsfig, 5 figure
Dilaton Brane Cosmology with Second Order String Corrections and the Cosmological Constant
We consider, in five dimensions, the effective action from heterotic string
which includes quantum gravity corrections up to (a')^2. The expansion, in the
string frame, is in terms of |a'R|, where R is the scalar curvature and uses
the third order Euler density, next to the Gauss-Bonnet term. For a positive
tension brane and infinite extra dimension, the logarithmic class of solutions
is less dependent from fine-tuning problems than in previous formulations. More
importantly, the model suggests that in the full non-perturbative formulation,
the string scale can be much lower than the effective Planck mass, without the
string coupling to be vanishingly small. Also a less severe fine-tuning of the
brane tension in needed.Comment: 19 pages, 5 figures LaTeX. Accepted for publication in IJMP
Skyrme models and nuclear matter equation of state
We investigate the role of pressure in a class of generalised Skyrme models. We introduce pressure as the trace of the spatial part of the energy-momentum tensor and show that it obeys the usual thermodynamical relation. Then, we compute analytically the mean-field equation of state in the high and medium pressure regimes by applying topological bounds on compact domains. The equation of state is further investigated numerically for the charge one skyrmions. We identify which term in a generalised Skyrme model is responsible for which part in the equation of state. Further, we compare our findings with the corresponding results in the Walecka model
Entropy of generic quantum isolated horizons
We review our recent proposal of a method to extend the quantization of
spherically symmetric isolated horizons, a seminal result of loop quantum
gravity, to a phase space containing horizons of arbitrary geometry. Although
the details of the quantization remain formally unchanged, the physical
interpretation of the results can be quite different. We highlight several such
differences, with particular emphasis on the physical interpretation of black
hole entropy in loop quantum gravity.Comment: 4 pages, contribution to loops '11 conference proceedings; 2
references added, a sentence remove
Eigenvalues of the volume operator in loop quantum gravity
We present a simple method to calculate certain sums of the eigenvalues of
the volume operator in loop quantum gravity. We derive the asymptotic
distribution of the eigenvalues in the classical limit of very large spins
which turns out to be of a very simple form. The results can be useful for
example in the statistical approach to quantum gravity.Comment: 12 pages, version accepted in Class. Quantum Gra
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