338,562 research outputs found
Survey of aircraft electrical power systems
Areas investigated include: (1) load analysis; (2) power distribution, conversion techniques and generation; (3) design criteria and performance capabilities of hydraulic and pneumatic systems; (4) system control and protection methods; (5) component and heat transfer systems cooling; and (6) electrical system reliability
Unified description of pairing, trionic and quarteting states for one-dimensional SU(4) attractive fermions
Paired states, trions and quarteting states in one-dimensional SU(4)
attractive fermions are investigated via exact Bethe ansatz calculations. In
particular, quantum phase transitions are identified and calculated from the
quarteting phase into normal Fermi liquid, trionic states and spin-2 paired
states which belong to the universality class of linear field-dependent
magnetization in the vicinity of critical points. Moreover, unified exact
results for the ground state energy, chemical potentials and complete phase
diagrams for isospin attractive fermions with external fields
are presented. Also identified are the magnetization plateaux of
and , where is the magnetization saturation value. The
universality of finite-size corrections and collective dispersion relations
provides a further test ground for low energy effective field theory.Comment: 13 pages, 4 figure
Drell-Yan process in soft-collinear effective theory near end-point
The Drell-Yan process is analyzed in soft-collinear effective theory near the
end-point region. It is assumed that the relevant final-state hadron energy
where is the momentum fraction transferred to the virtual photon
is the typical hadronic scale , thus no intermediate scale exists.
It is shown that this setup successfully reproduces the full theory results. We
also discuss the factorized soft Wilson lines for the Drell-Yan process.Comment: 18 pages, 6 figures. More discussions, references added. PRD accepted
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Quantitative absorption and fluorescence studies of NO between 1060 and 2000 A
Synchrotron radiation in the 1060 to 2000 A region was used to measure the average absorption and fluorescence cross sections of NO and to determine approximate photodissociation quantum yields. Several vibrational levels of the D(2) sigma(+), E(2) sigma(+), and B(2) delta states have high fluorescence quantum yields. The C(2) and B(2) states do not fluoresce when the excitation energies are above the first dissociation limit, in accord with previous experiments. In general, the fluorescence yields decrease with increasing photon energy. The quantitative measurements are compared with spectroscopic observations and are found to be reasonably consistent
Macroeconomic Stability, Governance and Growth: Empirical Lessons from the Post-Communist Transition
Using panel data for the period 1989-2006 we revisit the empirics of economic growth in the context of the post-communist transition. We pay particular attention to the mechanisms of causation and to the potential endogeneity of the macroeconomic stability indicators considered to be important in the existing literature. Carefully employing a variety of econometric techniques we consistently find that macroeconomic instability is bad for economic growth. We find some evidence that institutions of governance are important for economic growth through their influence on the macroeconomic environment. That is, good institutions are conducive to macroeconomic stability which in turn positively impacts upon economic growth. We also find, in contrast with other work, that investments in education have had a strong positive impact on growth in transition while other 'standard' economic growth determinants remain less important. These findings are shown to be robust to a variety of econometric approaches, specifications and time spans
Stochastic control system parameter identifiability
The parameter identification problem of general discrete time, nonlinear, multiple input/multiple output dynamic systems with Gaussian white distributed measurement errors is considered. The knowledge of the system parameterization was assumed to be known. Concepts of local parameter identifiability and local constrained maximum likelihood parameter identifiability were established. A set of sufficient conditions for the existence of a region of parameter identifiability was derived. A computation procedure employing interval arithmetic was provided for finding the regions of parameter identifiability. If the vector of the true parameters is locally constrained maximum likelihood (CML) identifiable, then with probability one, the vector of true parameters is a unique maximal point of the maximum likelihood function in the region of parameter identifiability and the constrained maximum likelihood estimation sequence will converge to the vector of true parameters
Comparative Aspects of Mating Behavior Patterns in Six Species of Stink Bugs (Heteroptera: Pentatomidae)
Mating sequences were analyzed for six species of stink bugs using video- tapes. The results consisted of qualitative descriptions of the precopulatory activities of the pairs and quantitative analyses of the number and direction of mating sequences, including the latency to and duration of copulatory lock. It was possible to quantitatively characterize each of the six species tested. In addition, certain infrequent behavior patterns, e.g., head butts, were observed for some species and not others. The results extend the previous information on mating activities in stink bugs, particularly for Euschistus. We interpret our findings with regard to reproductive strategies in different species of stink bugs, and consider the use of behavior as a taxonomic tool
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