22,763 research outputs found
Nuclear Structure in the UCOM Framework: From Realistic Interactions to Collective Excitations
The Unitary Correlation Operator Method (UCOM) provides a means for nuclear
structure calculations starting from realistic NN potentials. The dominant
short-range central and tensor correlations are described explicitly by a
unitary transformation. The application of UCOM in the context of the no-core
shell model provides insight into the interplay between dominant short-range
and residual long-range correlations in the nuclear many-body problem. The use
of the correlated interaction within Hartree-Fock, many-body perturbation
theory, and Random Phase Approximation gives access to various nuclear
structure observables throughout the nuclear chart.Comment: 9 pages, 3 figures, invited talk at the 2nd Int. Conf. on "Collective
Motion in Nuclei under Extreme Conditions" (COMEX 2), Sankt Goar, German
Vibration
Physiological and biomechanical responses of humans to vibrations during manned space flight and threshold data on tolerances to various vibrational modes and condition
Sound and noise
Sound and noise problems in space environment and human tolerance criteria at varying frequencies and intensitie
Nuclear Structure and Response based on Correlated Realistic NN Interactions
Starting from the Argonne V18 nucleon-nucleon (NN) interaction and using the
Unitary Correlation Operator Method, a correlated interaction v_UCOM has been
constructed, which is suitable for calculations within restricted Hilbert
spaces. In this work we employ the v_UCOM in Hartree-Fock, perturbation-theory
and RPA calculations and we study the ground-state properties of various
closed-shell nuclei, as well as some excited states. The present calculations
provide also important feedback for the optimization of the v_UCOM and valuable
information on its properties. The above scheme offers the prospect of ab
initio calculations in nuclei, regardless of their mass number. It can be used
in conjunction with other realistic NN interactions as well, and with various
many-body methods (Second RPA, QRPA, Shell Model, etc.).Comment: 3 pages, incl. 2 figures; Proc. Int. Conf. on Frontiers in Nuclear
Structure, Astrophysics and Reactions (FINUSTAR), Kos, Greece, Sept.200
Continued fractions for some transcendental numbers
We consider series of the form , where and the integer sequence satisfies a certain non-autonomous recurrence of second order, which entails that for n?1. It is shown that the terms of the sequence, and multiples of the ratios of successive terms, appear interlaced in the continued fraction expansion of the sum of the series, which is a transcendental number
Statistical properties of online auctions
We characterize the statistical properties of a large number of online
auctions run on eBay. Both stationary and dynamic properties, like
distributions of prices, number of bids etc., as well as relations between
these quantities are studied. The analysis of the data reveals surprisingly
simple distributions and relations, typically of power-law form. Based on these
findings we introduce a simple method to identify suspicious auctions that
could be influenced by a form of fraud known as shill bidding. Furthermore the
influence of bidding strategies is discussed. The results indicate that the
observed behavior is related to a mixture of agents using a variety of
strategies.Comment: 9 pages, 4 figures, to be published in Int. J. Mod. Phys.
Recommended from our members
Tree of Life Synagogue Shooting in Pittsburgh: Preparedness, Prehospital Care, and Lessons Learned
On Saturday, October 27, 2018, a man with anti-Semitic motivations entered Tree of Life synagogue in the Squirrel Hill section of Pittsburgh, Pennsylvania; he had an AR-15 semi-automatic rifle and three handguns, opening fire upon worshippers. Eventually 11 civilians died at the scene and eight people sustained non-fatal injuries, including five police officers. Each person injured but alive at the scene received care at one of three local level-one trauma centers. The injured had wounds often seen in war-settings, with the signature of high velocity weaponry. We describe the scene response, specific elements of our hospital plans, the overall out-of-hospital preparedness in Pittsburgh, and the lessons learned
- …