168 research outputs found
Longevity of 68 Species of Drosophila
Author Institution: Department of Biological Sciences, Bowling Green State UniversityAdult longevity of Drosophila is dependent upon many factors. In this study the differences in longevity caused by species, strain, sex, and mating status were examined for 68 species (89 strains) belonging to the D. obscura, melanogaster, and willistoni species groups. Both inter- and intra-specific differences in adult longevity were observed. In most species studied, females lived longer than males. In general, the longevity of unmated females exceeded that of mated ones, while the longevity of mated males was greater than that of unmated ones
Social cognition in schizophrenia: factor structure, clinical and functional correlates
Social cognition is consistently impaired in people with schizophrenia, separable from general neurocognition, predictive of real-world functioning, and amenable to psychosocial treatment. Few studies have empirically examined its underlying factor structure
Real measurements and Quantum Zeno effect
In 1977, Mishra and Sudarshan showed that an unstable particle would never be
found decayed while it was continuously observed. They called this effect the
quantum Zeno effect (or paradox). Later it was realized that the frequent
measurements could also accelerate the decay (quantum anti-Zeno effect). In
this paper we investigate the quantum Zeno effect using the definite model of
the measurement. We take into account the finite duration and the finite
accuracy of the measurement. A general equation for the jump probability during
the measurement is derived. We find that the measurements can cause inhibition
(quantum Zeno effect) or acceleration (quantum anti-Zeno effect) of the
evolution, depending on the strength of the interaction with the measuring
device and on the properties of the system. However, the evolution cannot be
fully stopped.Comment: 3 figure
Accelerating, hyperaccelerating, and decelerating networks
Many growing networks possess accelerating statistics where the number of links added with each new node is an increasing function of network size so the total number of links increases faster than linearly with network size. In particular, biological networks can display a quadratic growth in regulator number with genome size even while remaining sparsely connected. These features are mutually incompatible in standard treatments of network theory which typically require that every new network node possesses at least one connection. To model sparsely connected networks, we generalize existing approaches and add each new node with a probabilistic number of links to generate either accelerating, hyperaccelerating, or even decelerating network statistics in different regimes. Under preferential attachment for example, slowly accelerating networks display stationary scale-free statistics relatively independent of network size while more rapidly accelerating networks display a transition from scale-free to exponential statistics with network growth. Such transitions explain, for instance, the evolutionary record of single-celled organisms which display strict size and complexity limits
Quantum Zeno effect and parametric resonance in mesoscopic physics
As a realization of the quantum Zeno effect, we consider electron tunneling
between two quantum dots with one of the dots coupled to a quantum point
contact detector. The coupling leads to decoherence and to the suppression of
tunneling. When the detector is driven with an ac voltage, a parametric
resonance occurs which strongly counteracts decoherence. We propose a novel
experiment with which it is possible to observe both the quantum Zeno effect
and the parametric resonance in electric transport.Comment: 4 pages, 2 figure
Color Variability of the Blazar AO 0235+16
Multicolor (UBVRIJHK) observations of the blazar AO 0235+16 are analyzed. The
light curves were compiled at the Turin Observatory from literature data and
the results of observations obtained in the framework of the WEBT program
(http://www.to.astro/blazars/webt/). The color variability of the blazar was
studied in eight time intervals with a sufficient number of multicolor optical
observations; JHK data are available for only one of these. The spectral energy
distribution (SED) of the variable component remained constant within each
interval, but varied strongly from one interval to another. After correction
for dust absorption, the SED can be represented by a power law in all cases,
providing evidence for a synchrotron nature of the variable component. We show
that the variability at both optical and IR wavelengths is associated with the
same variable source.Comment: 11 pages, 9 figures, 4 tables, accepted for publication in Astronomy
Report
Continuous quantum measurement of a double dot
We consider the continuous measurement of a double quantum dot by a weakly
coupled detector (tunnel point contact nearby). While the conventional approach
describes the gradual system decoherence due to the measurement, we study the
situation when the detector output is explicitly recorded that leads to the
opposite effect: gradual purification of the double-dot density matrix.
Nonlinear Langevin equation is derived for the random evolution of the density
matrix which is reflected and caused by the stochastic detector output. Gradual
collapse, gradual purification, and quantum Zeno effect are naturally described
by the equation. We also discuss the possible experiments to confirm the
theory.Comment: Extended version (6 pages) of quant-ph/9807051, published in PR
Macroscopic quantum damping in SQUID rings
The measurement process is introduced in the dynamics of Josephson devices
exhibiting quantum behaviour in a macroscopic degree of freedom. The
measurement is shown to give rise to a dynamical damping mechanism whose
experimental observability could be relevant to understand decoherence in
macroscopic quantum systems.Comment: 7 Pages; Plain REVTeX; 3 Figures available upon request; to be
published in Phys. Lett. A 229, 23 (1997
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