5,455 research outputs found
The modular method: Milkfish pond culture
The modular method of milkfish culture (Chanos chanos) described in the manual is an improvement over the traditional extensive method. The manual is intended for the use of fish farmers and aquaculturists, extensionists, and students of aquaculture not only in the Philippines, but also in other milkfish-producing countries in Southeast Asia and the world. It covers the following: Interesting facts about milkfish -- biological characteristics, artificial breeding of milkfish; Design and operation of modular pond system -- pond preparation, stocking in the nursery or transition ponds, stocking in the rearing ponds, care of stock, pond utilization and production schedule, harvest and post-harvest; and, Economics and costing
Mudcrab, Scylla spp, production in brackishwater ponds
This manual covers the specifics of grow-out operation — site selection, pond specification, pond preparation, source of juveniles, transport and stocking, care of pond and stock, feeds and feeding, harvest, postharvest.
Also includes costs-and-benefits analysis and a list of useful references.Mudcrab (Scylla spp) production in brackishwater ponds is now gaining popularity, especially in communities that need to supplement their income. The manual covers the following: Distribution; Grow-out operation in ponds - site selection, pond specification, pond preparation, source of juveniles, transport and stocking of juveniles, care of pond and stock, feeds and feeding, harvest, post-harvest; Production and profits; Cost and analysis. It is hoped that the manual will be of use to fishfarmers and aquaculturists, extensionists, and students of aquaculture not only in the Philippines but also in other mudcrab producing countries in Southeast Asia
The Anisotropic Bak-Sneppen model
The Bak-Sneppen model is shown to fall into a different universality class with the introduction of a preferred direction, mirroring the situation in spin systems. This is first demonstrated by numerical simulations and subsequently confirmed by analysis of the multitrait version of the model, which admits exact solutions in the extremes of zero and maximal anisotropy. For intermediate anisotropies, we show that the spatiotemporal evolution of the avalanche has a power law `tail' which passes through the system for any non-zero anisotropy but remains fixed for the isotropic case, thus explaining the crossover in behaviour. Finally, we identify the maximally anisotropic model which is more tractable and yet more generally applicable than the isotropic system
Atomistic simulations of structural and thermodynamic properties of bilayer graphene
We study the structural and thermodynamic properties of bilayer graphene, a
prototype two-layer membrane, by means of Monte Carlo simulations based on the
empirical bond order potential LCBOPII. We present the temperature dependence
of lattice parameter, bending rigidity and high temperature heat capacity as
well as the correlation function of out-of-plane atomic displacements. The
thermal expansion coefficient changes sign from negative to positive above
K, which is lower than previously found for single layer graphene
and close to the experimental value of bulk graphite. The bending rigidity is
twice as large than for single layer graphene, making the out-of-plane
fluctuations smaller. The crossover from correlated to uncorrelated
out-of-plane fluctuations of the two carbon planes occurs for wavevectors
shorter than nmComment: 6 pages, 7 figures
An ultrahigh-speed digitizer for the Harvard College Observatory astronomical plates
A machine capable of digitizing two 8 inch by 10 inch (203 mm by 254 mm)
glass astrophotographic plates or a single 14 inch by 17 inch (356 mm by 432
mm) plate at a resolution of 11 microns per pixel or 2309 dots per inch (dpi)
in 92 seconds is described. The purpose of the machine is to digitize the
\~500,000 plate collection of the Harvard College Observatory in a five year
time frame. The digitization must meet the requirements for scientific work in
astrometry, photometry, and archival preservation of the plates. This paper
describes the requirements for and the design of the subsystems of the machine
that was developed specifically for this task.Comment: 12 pages, 9 figures, 1 table; presented at SPIE (July, 2006) and
published in Proceeding
Finite size effects in nonequilibrium wetting
Models with a nonequilibrium wetting transition display a transition also in
finite systems. This is different from nonequilibrium phase transitions into an
absorbing state, where the stationary state is the absorbing one for any value
of the control parameter in a finite system. In this paper, we study what kind
of transition takes place in finite systems of nonequilibrium wetting models.
By solving exactly a microscopic model with three and four sites and performing
numerical simulations we show that the phase transition taking place in a
finite system is characterized by the average interface height performing a
random walk at criticality and does not discriminate between the bounded-KPZ
classes and the bounded-EW class. We also study the finite size scaling of the
bKPZ universality classes, showing that it presents peculiar features in
comparison with other universality classes of nonequilibrium phase transitions.Comment: 14 pages, 6figures, major change
Universality and Crossover of Directed Polymers and Growing Surfaces
We study KPZ surfaces on Euclidean lattices and directed polymers on
hierarchical lattices subject to different distributions of disorder, showing
that universality holds, at odds with recent results on Euclidean lattices.
Moreover, we find the presence of a slow (power-law) crossover toward the
universal values of the exponents and verify that the exponent governing such
crossover is universal too. In the limit of a 1+epsilon dimensional system we
obtain both numerically and analytically that the crossover exponent is 1/2.Comment: LateX file + 5 .eps figures; to appear on Phys. Rev. Let
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