1,486 research outputs found

    Triaxial Analytical Potential-Density Pairs for Galaxies

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    We present two triaxial analytical potential-density pairs that can be viewed as generalized versions of the axisymmetric Miyamoto and Nagai and Satoh galactic models. These potential-density pairs may be useful models for galaxies with box-shaped bulges. The resulting mass density distributions are everywhere non-negative and free from singularities. Also, a few numerically calculated orbits for the Miyamoto and Nagai-like triaxial potential are presented.Comment: 9 pages, 4 figures, accepted for publication in PAS

    Prospects for quarkonia production studies in U+U collisions

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    Collisions of deformed uranium nuclei provide a unique opportunity to study the spatial dependence of charmonium in-medium effects. By selecting the orientations of the colliding nuclei, different path lengths through the nuclear medium could be selected within the same experimental environment. In addition, higher energy densities can be achieved in U+U collisions relative to Au+Au collisions. In this paper, we investigate the prospects for charmonium studies with U+U collisions. We discuss the effects of shadowing and nuclear absorption on the J/\psi\ yield. We introduce a new observable which could help distinguish between different types of J/\psi\ interactions in hot and dense matter.Comment: 13 pages, 10 figure

    Electric-field induced dipole blockade with Rydberg atoms

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    High resolution laser Stark excitation of np (60 < n < 85) Rydberg states of ultra-cold cesium atoms shows an efficient blockade of the excitation attributed to long-range dipole-dipole interaction. The dipole blockade effect is observed as a quenching of the Rydberg excitation depending on the value of the dipole moment induced by the external electric field. Effects of eventual ions which could match the dipole blockade effect are discussed in detail but are ruled out for our experimental conditions. Analytic and Monte-Carlo simulations of the excitation of an ensemble of interacting Rydberg atoms agree with the experiments indicates a major role of the nearest neighboring Rydberg atom.Comment: 4 page

    Using the eSana Framework in Dermatology to improve the Information Flow between Patients and Doctors

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    Mobile devices are becoming ubiquitous in every day\u27s life; their time and place independence are reasons for using them in different areas. One such area is electronic health, where patients can install small applications on their mobile devices that help or guide them in the management of their disease. The eSana framework offers a set of tools and approaches that allow the transmission of discrete physiological values electronically in order to evaluate them by medical experts. This paper presents an application scenario in the field of dermatology. It illustrates the information flow between patient and dermatologist including all transformation services. One speciality is the combination of binary image data and structured information about a given condition sent over a mobile network. The main goal is to show a set of necessary components in order to support the relationship between patients and their dermatologists by using medical standards

    EEG and behavioural correlates of different forms of motor imagery during action observation in rhythmical actions

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    Recent studies show that participants can engage in motor imagery (MI) and action observation (AO) simultaneously (AO + MI), indicating a capacity for dual action simulation. Here we studied the electrophysiological correlates and behavioural outcomes of two forms of AO + MI, along with pure MI and pure AO control conditions. In synchronised AO + MI, participants imagined performing a rhythmical action in synchrony with an observed distractor action. In contrast in static AO + MI, where the imagery served to conflict with AO, participants imagined holding a static hand posture during AO. Following synchronised AO + MI, rhythmical execution was strongly biased toward the cycle time of the previously observed rhythm (‘imitation bias’), whereas a weaker bias was found following pure MI, and particularly for static AO + MI. In line with these findings, event-related desynchronisation (ERD) in primary sensorimotor and parietal regions was more pronounced in synchronised AO + MI compared to both pure AO and pure MI. These ERD amplitudes were, however, highly similar for static and synchronised AO + MI; suggesting that, regardless of co-represented content, both AO + MI states produced stronger motor activations than single action simulation. In contrast, synchronised AO + MI produced significantly stronger ERD in rostral prefrontal cortex compared to the other three conditions. This specific rostral prefrontal involvement most likely reflected additional cognitive processing for aligning dual action simulations. Together these results provide an important empirical validation of different AO + MI states, in that the imitation bias was strongly modulated by the content of the AO + MI instructions, and that synchronised AO + MI produced stronger behavioural and neurophysiological effects compared to pure AO or MI

    Scale invariance and viscosity of a two-dimensional Fermi gas

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    We investigate the collective excitations of a harmonically trapped two-dimensional Fermi gas from the collisionless (zero sound) to the hydrodynamic (first sound) regime. The breathing mode, which is sensitive to the equation of state, is observed at a frequency two times the dipole mode frequency for a large range of interaction strengths and temperatures, and the amplitude of the breathing mode is undamped. This provides evidence for a dynamical SO(2,1) scaling symmetry of the two-dimensional Fermi gas. Moreover, we investigate the quadrupole mode to measure the shear viscosity of the two-dimensional gas and study its temperature dependence
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