611 research outputs found
Fukushima plutonium effect and blow-up regimes in neutron-multiplying media
It is shown that the capture and fission cross-sections of 238U and 239Pu
increase with temperature within 1000-3000 K range, in contrast to those of
235U, that under certain conditions may lead to the so-called blow-up modes,
stimulating the anomalous neutron flux and nuclear fuel temperature growth.
Some features of the blow-up regimes in neutron-multiplying media are
discussed.Comment: 15 pages, 8 figures. (v2: numerous corrections and style
improvements). arXiv admin note: substantial text overlap with
arXiv:1207.369
Mechanism of Deep-focus Earthquakes Anomalous Statistics
Analyzing the NEIC-data we have shown that the spatial deep-focus earthquake
distribution in the Earth interior over the 1993-2006 is characterized by the
clearly defined periodical fine discrete structure with period L=50 km, which
is solely generated by earthquakes with magnitude M 3.9 to 5.3 and only on the
convergent boundary of plates. To describe the formation of this structure we
used the model of complex systems by A. Volynskii and S. Bazhenov. The key
property of this model consists in the presence of a rigid coating on a soft
substratum. It is shown that in subduction processes the role of a rigid
coating plays the slab substance (lithosphere) and the upper mantle acts as a
soft substratum. Within the framework of this model we have obtained the
estimation of average values of stress in the upper mantle and Young's modulus
for the oceanic slab (lithosphere) and upper mantle.Comment: 9 pages, 7 figure
Lamellar bone is an incremental tissue reconciling enamel rhythms, body size, and organismal life history
Mammalian enamel formation is periodic,including fluctuations attributable to the daily biological clock as well as longer-period oscillations that enigmatically correlate with body mass. Because the scaling of bone mass to body mass is an axiom of vertebrate hard tissue biology,we consider that long-period enamel formation rhythms may reflect corresponding and heretofore unrecognized rhythms in bone growth. The principal aim of this study is to seek a rhythm in bone growth demonstrably related to enamel oscillatory development. Our analytical approach is based in morphology, using a variety of hard tissue microscopy techniques. We first ascertain the relationship among long-period enamel rhythms, the striae of Retzius, and body mass using a large sample of mammalian taxa. In addition, we test whether osteocyte lacuna density (a surrogate for rates of cell proliferation) in bone is correlated with mammalian body mass. Finally, using fluorescently labeled developing bone tissues, we investigate whether the bone lamella,a fundamental microanatomical unit of bone, relates to rhythmic enamel growth increments. Our results confirm a positive correlation between long-period enamel rhythms and body mass and a negative correlation between osteocyte density and body mass. We also confirm that lamellar bone is an incremental tissue, one lamella formed in the species-specific time dependency of striae of Retzius formation. We conclude by contextualizing our morphological research with a current understanding of autonomic regulatory control of the skeleton and body mass, suggesting a central contribution to the coordination of organismal life history and body mass
Galactic Cosmic Rays - Clouds Effect and Bifurcation Model of the Earth Global Climate. Part 2. Comparison of Theory with Experiment
The solution of energy-balance model of the Earth global climate and the
EPICA Dome C and Vostok experimental data of the Earth surface
palaeotemperature evolution over past 420 and 740 kyr are compared. In the
framework of proposed bifurcation model (i) the possible sharp warmings of the
Dansgaard-Oeschger type during the last glacial period due to stochastic
resonance is theoretically argued; (ii) the concept of climatic sensitivity of
water in the atmosphere, whose temperature instability has the form of
so-called hysteresis loop, is proposed, and based of this concept the time
series of global ice volume over the past 1000 kyr, which is in good agreement
with the time series of delta O-18 concentration in the sea sediments, is
obtained; (iii) the so-called "CO2 doubling" problem is discussedComment: 19 pages, 4 figure
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