2,421 research outputs found
Bergin, Anthony and Hall, Robert, eds. Intelligence and Australian National Security-, Canberra: Australian Defence Studies Centre, 1994.
The Steady State Distribution of the Master Equation
The steady states of the master equation are investigated. We give two
expressions for the steady state distribution of the master equation a la the
Zubarev-McLennan steady state distribution, i.e., the exact expression and an
expression near equilibrium. The latter expression obtained is consistent with
recent attempt of constructing steady state theormodynamics.Comment: 6 pages, No figures. A mistake was correcte
Investigation of the difficulties associated with the use of lead telluride and other II - IV compounds for thin film thermistors
The fabrication of thermistors was investigated for use as atmospheric temperature sensors in meteorological rocket soundings. The final configuration of the thin film thermistor is shown. The composition and primary functions of the six layers of the sensor are described. A digital controller for thin film deposition control is described which is capable of better than .1 A/sec rate control. The computer program modules for digital control of thin film deposition processing are included
An expression for stationary distribution in nonequilibrium steady state
We study the nonequilibrium steady state realized in a general stochastic
system attached to multiple heat baths and/or driven by an external force.
Starting from the detailed fluctuation theorem we derive concise and suggestive
expressions for the corresponding stationary distribution which are correct up
to the second order in thermodynamic forces. The probability of a microstate
is proportional to where
is the excess entropy change.
Here is the difference between two kinds of conditioned
path ensemble averages of excess heat transfer from the -th heat bath whose
inverse temperature is . Our expression may be verified experimentally
in nonequilibrium states realized, for example, in mesoscopic systems.Comment: 4 pages, 2 figure
Interactions between parental traits, environmental harshness and growth rate in determining telomere length in wild juvenile salmon
A larger body size confers many benefits, such as increased reproductive success, ability to evade predators and increased competitive ability and social status. However, individuals rarely maximise their growth rates, suggesting that this carries costs. One such cost could be faster attrition of the telomeres that cap the ends of eukaryotic chromosomes and play an important role in chromosome protection. A relatively short telomere length is indicative of poor biological state, including poorer tissue and organ performance, reduced potential longevity and increased disease susceptibility. Telomere loss during growth may also be accelerated by environmental factors, but these have rarely been subjected to experimental manipulation in the natural environment. Using a wild system involving experimental manipulations of juvenile Atlantic salmon Salmo salar in Scottish streams, we found that telomere length in juvenile fish was influenced by parental traits and by direct environmental effects. We found that faster-growing fish had shorter telomeres and there was a greater cost (in terms of reduced telomere length) if the growth occurred in a harsher environment. We also found a positive association between offspring telomere length and the growth history of their fathers (but not mothers), represented by the number of years fathers had spent at sea. This suggests that there may be long term consequences of growth conditions and parental life history for individual longevity
A dynamical theory of homogeneous nucleation for colloids and macromolecules
Homogeneous nucleation is formulated within the context of fluctuating
hydrodynamics. It is shown that for a colloidal or macromolecular system in the
strong damping limit the most likely path for nucleation can be determined by
gradient descent in density space governed by a nontrivial metric fixed by the
dynamics. The theory provides a justification and extension of more heuristic
equilibrium approaches based solely on the free energy. It is illustrated by
application to liquid-vapor nucleation where it is shown that, in contrast to
most free energy-based studies, the smallest clusters correspond to long
wavelength, small amplitude perturbations.Comment: final version; 4 pages, 2 figure
Phase diagram and universality of the Lennard-Jones gas-liquid system
The gas-liquid phase transition of the three-dimensional Lennard-Jones
particles system is studied by molecular dynamics simulations. The gas and
liquid densities in the coexisting state are determined with high accuracy. The
critical point is determined by the block density analysis of the Binder
parameter with the aid of the law of rectilinear diameter. From the critical
behavior of the gas-liquid coexsisting density, the critical exponent of the
order parameter is estimated to be . Surface tension is
estimated from interface broadening behavior due to capillary waves. From the
critical behavior of the surface tension, the critical exponent of the
correlation length is estimated to be . The obtained values of
and are consistent with those of the Ising universality class.Comment: 8 pages, 8 figures, new results are adde
Shorter juvenile telomere length is associated with higher survival to spawning in migratory Atlantic salmon
The risk of mortality associated with a long-distance migration will depend on an animal's physiological state, as well as the prevailing ecological conditions. Here we assess whether juvenile telomere length, which in endotherms has been shown to be a biomarker of physiological state and expected lifespan, predicts whether wild Atlantic salmon Salmo salar successfully complete their marine migration.
Over 1800 juvenile fish were trapped, measured, PIT-tagged and a tissue biopsy taken when migrating as juveniles down-river towards the sea. Survivors of the marine phase of the life cycle were then re-trapped and re-sampled when returning to the river to spawn as sexually mature adults, 1.5-2.5 years later. Most individuals experienced a reduction in telomere length during the marine migratory phase of their life cycle. While the relative rate of telomere loss was greater in males than females, telomere loss was unrelated to growth at sea.
Contrary to expectations, salmon that had the shortest telomeres at the time of the outward migration had the greatest probability of surviving through to the return migration. This effect, independent of body size, may indicate a trade-off between investment in readiness for marine life (which favours high glucocorticoid levels, known to increase telomere attrition in other vertebrate species) and investment in telomere maintenance. Survival was also significantly influenced by the seasonal timing of outward migration, with the fish migrating downstream earliest in the spring having the highest probability of return.
This study reveals that telomere length is associated with survival, although in ways that contrast with patterns seen in endotherms. This illustrates that while telomeres may be universally important for chromosome protection, the potential for telomere dynamics to predict performance may vary across taxa
The law of action and reaction for the effective force in a nonequilibrium colloidal system
We study a nonequilibrium Langevin many-body system containing two 'test'
particles and many 'background' particles. The test particles are spatially
confined by a harmonic potential, and the background particles are driven by an
external driving force. Employing numerical simulations of the model, we
formulate an effective description of the two test particles in a
nonequilibrium steady state. In particular, we investigate several different
definitions of the effective force acting between the test particles. We find
that the law of action and reaction does not hold for the total mechanical
force exerted by the background particles, but that it does hold for the
thermodynamic force defined operationally on the basis of an idea used to
extend the first law of thermodynamics to nonequilibrium steady states.Comment: 13 page
Hot Brownian Motion
We derive the generalized Markovian description for the non-equilibrium
Brownian motion of a heated particle in a simple solvent with a
temperature-dependent viscosity. Our analytical results for the generalized
fluctuation-dissipation and Stokes-Einstein relations compare favorably with
measurements of laser-heated gold nano-particles and provide a practical
rational basis for emerging photothermal technologies.Comment: 10 pages, 5 figure
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